Rwhp vs engine dyno

[metcoll]

From research my engine should have 500 to 520 flywheel hp..but when went on the dynojet I put down around 360 to the wheels..my combo is a 440, 2355 pistons,rpm heads ported flow282 @ 600,cam is a hydraulic 240/250 520/547 lift,rpm intake,850 dbl. pump carb,msd ignition and 13/4 headers going into 2.5 exhaust...as for the rest it is an auto with a 4200 stall and 4.56 gears...compression is 170-180 psi..my question is do you lose that much power through the drivetrain

[cdr]

air filter, exhaust, fan blade, water pump, alternator, power steering pump & THEN the drive train. most engine dyno's dont have these parasitic items hooked up while running them, there is NET HP at the flywheel & there is Gross HP at the Flywheel. a;so a REAL 500hp fywheel , is a badass street car. take it to the track & see what it runs.

[cdr]

lets say you are making 500 Gross BHP, take approx 60 hp off for the items I mentioned, could be more or less a lot depends on the type of muffler you have, 500-60=440, lets say 14% drive train loss, 440 x .86 = 378 rwhp Dyno Jet tends to read higher HP that a Mustang

[metallicareload99]

From research my engine should have 500 to 520 flywheel hp..but when went on the dynojet I put down around 360 to the wheels..my combo is a 440, 2355 pistons,rpm heads ported flow282 @ 600,cam is a hydraulic 240/250 520/547 lift,rpm intake,850 dbl. pump carb,msd ignition and 13/4 headers going into 2.5 exhaust...as for the rest it is an auto with a 4200 stall and 4.56 gears...compression is 170-180 psi..my question is do you lose that much power through the drivetrain

Your 440 is similar to mine and the fastest I went at the track last year was 106 mph.  According to the Moroso calculator and based on my weight I was making 375 HP or so

[BSB67]

....my question is do you lose that much power through the drivetrain

Probably not.  But I don't know if I would necessarily believe the 500-520, nor the 360.  And seriously, I would not get too wrapped up on either of them.  I also think that Charlie's explanation is pretty good too.   

If you're concerned about track performance, go to the track and start dialing-in the car.  If you are not interested in the track, and you're happy with the way it runs, I suggest you move on and enjoy the car.  You'll chase yourself in circles on this horsepower thing.

My gut feeling is that 360 RWHP will put down a pretty decent number at the track, although my limited experiences are with Mustang dynos.

[BSB67]

From research my engine should have 500 to 520 flywheel hp..but when went on the dynojet I put down around 360 to the wheels..my combo is a 440, 2355 pistons,rpm heads ported flow282 @ 600,cam is a hydraulic 240/250 520/547 lift,rpm intake,850 dbl. pump carb,msd ignition and 13/4 headers going into 2.5 exhaust...as for the rest it is an auto with a 4200 stall and 4.56 gears...compression is 170-180 psi..my question is do you lose that much power through the drivetrain

Your 440 is similar to mine and the fastest I went at the track last year was 106 mph.  According to the Moroso calculator and based on my weight I was making 375 HP or so

I do love the Moroso Calculator.  For me its what levels the playing field for comparison purposes.  You can also use Mopar's published "Dragstrip Dyno".  It does the same thing as the Moroso Calculator, but the results are a littler higher.  So if your looking to rationalize a higher hp, use the Mopar calculation. It also has a nice narrative that is educational. 

Despite popular belief, the Moroso calculator is not RWHP.  MPH is was you use for estimating hp (not et).  If you use the track mph, and race weight, the slide rule will give you a net, actual flywheel hp.  If you correct the mph to standard conditions, the slide rule will give you net corrected hp).  Then, as Charlie stated, the remaining difference between the a true dyno corrected gross flywheel hp and the corrected net hp will be the items Charlie stated above.The best you can do is estimate these.

My experience is if you start with a not to happy dyno, these numbers line up pretty well, and consistently.

[INTMD8]

.my question is do you lose that much power through the drivetrain

You can lose quite a bit with a loose converter. 

Look at the dyno run in mph instead of rpm, calculate what mph would be with no converter slip at peak rpm to figure out slip on the dyno.

Inefficient converter is converting power to heat vs putting it to the tires.

High numeric gears (such as yours) also contribute to inertial loss. (If you had a 2.73 for example you accelerate the mass at a slower rate)

Agreed on, bring it to the track and go from there.

[firefighter3931]

Chassis dyno is mainly a tuning tool, in my opinion. Good for dialing in the timing & fuel curves. The track will tell you how much power it's really making. All you need is the MPH and raceweight as mentioned above....then it's just math, pure and simple. 


Ron

[c00nhunterjoe]

Chassis dynos are good for chest pounding in my opinion, Which is why you are upset by the number. So i ask, what does that number actually mean to you for your car? What does it matter if it is higher or lower? The dyno and dyno operater can manipulate the readings from car to car. You may make 350 on 1, go to the next one and make 400. So who cares? Just my 2 cents. Take it to the track as others have stated, but dont forget to get the weather conditions at the time of your run to get your corrected numbers as well. If you do not have a weather station, here is a decent site to use.
https://airdensityonline.com/track-results/Cecil_County_Dragway/

[flyinlow]

Educate me please;

car A race weight 4250 with 400 Hp ,2.76 axle and a 727TF  goes   XXX mph in the traps

car B race weight 4250 with 400 HP, 4.10 axle and  ZF eight speed goes the same mph?

Is that simple of a calculator accurate.

[cdr]

Educate me please;

car A race weight 4250 with 400 Hp ,2.76 axle and a 727TF  goes   XXX mph in the traps

car B race weight 4250 with 400 HP, 4.10 axle and  ZF eight speed goes the same mph?

Is that simple of a calculator accurate.

They would be a couple of MPH within each other, but does the ZF use more or less HP, it would take testing to find out.

[c00nhunterjoe]

Educate me please;

car A race weight 4250 with 400 Hp ,2.76 axle and a 727TF  goes   XXX mph in the traps

car B race weight 4250 with 400 HP, 4.10 axle and  ZF eight speed goes the same mph?

Is that simple of a calculator accurate.

The 2.76 and 4.10 have no bearing on mph, only et, assuming the preloads on the bearings are the same but we are splitting hairs there. If the car with the zf has the same mph as the 727 car and the cars were run at the same track and same weather conditions, then the car with the 727 makes more hp as a stock 727 takes more hp to turn the zf.

[metcoll]

Has anyone here had there vehicle dynoed on a chassis dyno & engine dyno

[c00nhunterjoe]

If someone wants to pay for it, i will put mine on the rollers. Lol. I have engine sheets.

[flyinlow]

With out the transmission our Charger engines are just expensive battery chargers. It is hard to believe that the gear box has little to no effect on trap speed.

Lets say in the earlier example car A and car B engines both peak Hp. is at 5500rpm.

A CVT transmission would allow the engine to sit at 5500rpm for the whole run.  Best run ?

Lets say that car A has a manual Valve Body and you put the car in 3rd. (single speed trans, I have done this with the '70 Charger , is pretty lame performance below 80mph ) worst run ?

Car B's 8 speed lets it stay at peak (or very close to) rpm for most of the run.  pretty close to CVT transmission maybe better with a good converter.?


Just hanger flying here.

[BSB67]

In extreme cases like in your example, there would be some difference.  Probably less than you think.

There are actually two formula for for manual and automatic trannys.  But they are close. 

Changes in rotating mass and rolling resistance will make a difference too. 

These formula are empirically derived and represents best fit of a lot of data.

To me it is still better for comparative purposes.  Even knowing that the formula are not perfect, I would trust it far more than anyone posting a dyno sheet on a forum.

[BSB67]

Has anyone here had there vehicle dynoed on a chassis dyno & engine dyno

yes

[cdr]

In extreme cases like in your example, there would be some difference.  Probably less than you think.

There are actually two formula for for manual and automatic trannys.  But they are close. 

Changes in rotating mass and rolling resistance will make a difference too. 

These formula are empirically derived and represents best fit of a lot of data.

To me it is still better for comparative purposes.  Even knowing that the formula are not perfect, I would trust it far more than anyone posting a dyno sheet on a forum.

This ^^^^^^^^^^, I have seen many 700hp Dyno sheet cars that run at the track like a 550hp engine.

[c00nhunterjoe]

In extreme cases like in your example, there would be some difference.  Probably less than you think.

There are actually two formula for for manual and automatic trannys.  But they are close. 

Changes in rotating mass and rolling resistance will make a difference too. 

These formula are empirically derived and represents best fit of a lot of data.

To me it is still better for comparative purposes.  Even knowing that the formula are not perfect, I would trust it far more than anyone posting a dyno sheet on a forum.

This ^^^^^^^^^^, I have seen many 700hp Dyno sheet cars that run at the track like a 550hp engine.

And the reverse- i can give you a 580hp dyno sheet that puts a 69 b body into the 9s....at stock weight.

[INTMD8]

With out the transmission our Charger engines are just expensive battery chargers. It is hard to believe that the gear box has little to no effect on trap speed.

Lets say in the earlier example car A and car B engines both peak Hp. is at 5500rpm.

A CVT transmission would allow the engine to sit at 5500rpm for the whole run.  Best run ?

Lets say that car A has a manual Valve Body and you put the car in 3rd. (single speed trans, I have done this with the '70 Charger , is pretty lame performance below 80mph ) worst run ?

Car B's 8 speed lets it stay at peak (or very close to) rpm for most of the run.  pretty close to CVT transmission maybe better with a good converter.?


Just hanger flying here.

Yes it makes a big difference.  Gearing to maximize your ability to keep the engine at/around peak HP maximizes rear wheel torque at any speed. 

So final drive, how many gears and if auto, the torque converter all comes into play to achieve this.

As your example, you can see how many cars with similar engine horsepower are much quicker/faster in the quarter when they moved to 6 then 8 and 10 speed transmissions.

The lack of ratios in older transmissions can in some part be overcome by a loose converter but now you are converting some more power to heat rather than making it's way to the tires.

As to the question of, has anyone ran their engine on an engine dyno vs a chassis dyno, the answer is yes and still would vary on a case by case basis as the power loss would be different from car to car unless they were all using the exact same components from the flywheel back.

[BSB67]

Yes it makes a big difference.  Gearing to maximize your ability to keep the engine at/around peak HP maximizes rear wheel torque at any speed. 

So final drive, how many gears and if auto, the torque converter all comes into play to achieve this.

As your example, you can see how many cars with similar engine horsepower are much quicker/faster in the quarter when they moved to 6 then 8 and 10 speed transmissions.

The lack of ratios in older transmissions can in some part be overcome by a loose converter but now you are converting some more power to heat rather than making it's way to the tires.

As to the question of, has anyone ran their engine on an engine dyno vs a chassis dyno, the answer is yes and still would vary on a case by case basis as the power loss would be different from car to car unless they were all using the exact same components from the flywheel back.

What are you calling a big difference?  Do you have some data or examples to show this big difference?   How does this wash with the popularity of the powerglide?

How does max horsepower maximize torque?  What does maximum torque maximize?

I'm not saying that minimize the engine rpm around the peak power doesn't have some benefit, but your statements seem a bit arbitrary.

[BSB67]

With out the transmission our Charger engines are just expensive battery chargers. It is hard to believe that the gear box has little to no effect on trap speed.

Lets say in the earlier example car A and car B engines both peak Hp. is at 5500rpm.

A CVT transmission would allow the engine to sit at 5500rpm for the whole run.  Best run ?

Lets say that car A has a manual Valve Body and you put the car in 3rd. (single speed trans, I have done this with the '70 Charger , is pretty lame performance below 80mph ) worst run ?

Car B's 8 speed lets it stay at peak (or very close to) rpm for most of the run.  pretty close to CVT transmission maybe better with a good converter.?


Just hanger flying here.

If you have a car start is second gear verses 1st (manual valve body), it will mph about the same.  If you have a car with a 4.10, and switch to a 3.23, it will mph the same.  If you have a run where the tires break loose and you have a 3.5 sec 60 ft time verses a normal 1.8 60 ft time, the mph will be the same.

[INTMD8]

Allow me to repeat myself.

Keeping the engine at/near peak horsepower maximizes -wheel- torque which maximizes acceleration.  

Once again, this can be achieved with many gears, or a loose converter and less gears. (except loose converter loses efficiency to heat).

See a lot of powerglide cars with a stock torque converter run well?  

Do you see what the new 8 and 10 speed auto cars run compared to the old 2/3/4 speed autos with similar power to weight ratio.

I have no problem explaining this in depth but not going to waste my time if you want to dismiss it as arbitrary without trying to understand what is being said.

[cdr]

Allow me to repeat myself.

Keeping the engine at/near peak horsepower maximizes -wheel- torque which maximizes acceleration.  

Once again, this can be achieved with many gears, or a loose converter and less gears. (except loose converter loses efficiency to heat).

See a lot of powerglide cars with a stock torque converter run well?  

Do you see what the new 8 and 10 speed auto cars run compared to the old 2/3/4 speed autos with similar power to weight ratio.

I have no problem explaining this in depth but not going to waste my time if you want to dismiss it as arbitrary without trying to understand what is being said.

Hellcat with a 8 speed runs just what it should for the HP the engine makes, no reason to be an ASSHOLE

[cdr]

An 8 speed trans has 7 shifts, each shift takes time to make the shift, a power glide has one shift that takes time to shift, easy math. between each shift the car slows down & then picks back up. yes the time is in milliseconds but they add up over 7 shifts

[INTMD8]

Ok, instead of having a discussion just skim over what I wrote and call it arbitrary. THAT is being an asshole.

Want me to program my Hellcat to run through the quarter in 2 gears soo you can see the difference?

Never mind power glide is the best. Launch in high gear to save yourself the wasted time of that shift 

[cdr]

Ok, instead of having a discussion just skim over what I wrote and call it arbitrary. THAT is being an asshole.

Want me to program my Hellcat to run through the quarter in 2 gears soo you can see the difference?

Never mind power glide is the best. Launch in high gear to save yourself the wasted time of that shift 

LMAO !!! you are the one not getting it, talking about MPH, not et

[BSB67]

Sorry.  I'm really slow.  

"Keeping the engine at/near peak horsepower maximizes -wheel- torque which maximizes acceleration. "

I don't understand this statement.  I'm looking at my engine dyno results and my chassis dyno results.  My engine makes peak hp at about 5600 rpm. On the chassis dyno my tires are making peak torque at about 4000 engine rpm.   Can you explain why my max wheel torque does not match my peak engine power like you say it should?


"Do you see what the new 8 and 10 speed auto cars run compared to the old 2/3/4 speed autos with similar power to weight ratio."

No, I don't see.  Can you show me?  Preferably same car and engine, two different trannys.

[INTMD8]

Sorry.  I'm really slow.  

"Keeping the engine at/near peak horsepower maximizes -wheel- torque which maximizes acceleration. "

I don't understand this statement.  I'm looking at my engine dyno results and my chassis dyno results.  My engine makes peak hp at about 5600 rpm. On the chassis dyno my tires are making peak torque at about 4000 engine rpm.   Can you explain why my max wheel torque does not match my peak engine power like you say it should?


"Do you see what the new 8 and 10 speed auto cars run compared to the old 2/3/4 speed autos with similar power to weight ratio."

No, I don't see.  Can you show me?  Preferably same car and engine, two different trannys.

I didn't say wheel torque matches peak engine power. I said gearing the car to keep the engine at/near max HP maximizes wheel torque.

Gearing is calculated on any chassis dyno.  This is why you don't see 3000ft/lbs to the wheels if you made a 1st gear dyno pull, gearing is calculated automatically as it knows mph and with an RPM input can automatically calculate overall gearing.

You will see variances in measured wheel hp depending on what gear you run it in as the higher the gear the slower the rate. (RPM per second).  If you are in a lower gear and accelerating 1000rpm/sec you lose more parasitic to accelerating mass, or inertial loss.   Higher gear and 400/rpm sec is less inertial loss.  The other variant is gearing efficiency as 1-1 is generally the least amount of loss vs an under or over drive gear.

As for keeping the engine at/near peak hp. (you want to be at the same horsepower before/after the shift,  when leaving one gear and moving to the next, this keeps it in the highest average hp going down the track). 

More gears equals a narrower window and the ability to keep it closer to peak hp.  Wider gears do the opposite. Of course as mentioned a loose converter will achieve this as well but in the way of slippage (and slippage converts crank hp to heat in the way of heating the transmission fluid, it is power lost that could have went to the rear tires).

Here is a calculator you could use to get a general idea though it will only give you real results for a manual transmission or locked converter. (as rpm drop would be much less than calculated with converter slip)    http://glennmessersmith.com/shiftpt.html

As for a comparison, lets take the Mustang GT.

2017 GT with 6 speed auto has 435hp, 3,800lbs  8.73lbs per hp and runs 12.8-13.0 at 110-112mph

2018 GT with 10 speed auto has 460hp, 3,860lbs  8.39lbs per hp and runs 11.8-12.0 at 118-119mph


You would think the addition of 25hp and 50lbs curb weight might result in 2 tenths/2mph faster but it is much much faster.

There was a drastic jump in performance with only a slight hp gain in the F150's as well when going from 6 to 10 speed.

Of course adding a converter to the 6 speed auto car would narrow the gap but as it is I would say that's a big difference.

You guys seeing zero difference in mph going from very low to very high numeric ratios, that does not mirror my experience unless again, it was compensated for by converter slip or the change to a higher numeric ratio put the engine well past it's optimum shift rpm through the traps.

[c00nhunterjoe]

The bottom line is horsepower dictates the mph, not the transmission or rear gear ratio. The transmission and rear gears can effect the e.t. that is fact across the entire mathematical board.

If your arguement is valid, then refresh my memory of how many gears are in the tranmission of top fuel cars and what temperature they run at?

[c00nhunterjoe]

170-180 mph in the 1/4. Count the shifts in supergas..... so why dont they run 10 speeds?
https://youtu.be/ZD1xX4UR2-U

[c00nhunterjoe]

Your 707 hp hellcat has 8 gears and 150 more hp then my friends roadrunner with only 3 gears and he is a full second faster then your hellcat in the 1/4 mile. Why? You have 5 more gears then him?

[INTMD8]

If those are your actual questions it's clear you've read nothing I've written. Continuing to discuss this with you is pointless.

[BSB67]

Thank you.

I don't dispute the variances in both engine and more so chassis dynos.

I don't dispute the narrowing the engine rpm around peak power improves performance.  I think I've said that twice now.  Bigger improvement in et, less in mph.

I'll further concede that the amount of change in mph will also be a function of that particular engine's power curve.  The narrower shift recovery on the A833 helps a 340 more than a 440 more than a 500 in motor.

Thank you for the example comparison.  However, I'm always a skeptic.  Are those HP figures factory, or on your dyno?  Factory HP numbers are not necessarily apples to apples, even between same model but different years.  Second, they are different cars.  Two different cars with two different motors with two different transmissions are enough variables for me to question the conclusion that the sole reason for the mph increase is the additional gears. Third, were the two track runs corrected to common standard atmospheric conditions?

My comments on final gear ratio come from a lot of personal experience, and confirmed often by others I trust that have well vetted cars that spend a lot of time at the track.    My two very best examples are with me and two of my race buddies.  Similar stories, but ill tell one. Side by side race all the time. My car was slightly quicker, and faster.  He changes gears. Back to side by side racing following week. He hole shot me big time.  Instead of being even up with him, I was a car back.  That all happened in the first 100 ft or so. Then it turned into the exact same race we always have, except instead of me being even, I'm behind a car length. At half track, I start to catch him, which is exactly where I normally start to pull away. At the traps, I recover about fender, the same distance I'm usually ahead.  The time slip shows the same 1 mph difference we've seen in the previous 50 passes together.  We probably made 4 more passes the day, same result.  The beauty of this example is it neutralizes a bunch of variables.  I'll add that neither of these cars are back in their converters on shift recovery.

Anyways, I'll stand by my earlier statements regarding the mph/horsepower relationship.   And when using it to compare similar cars, the delta HP is pretty solid.  I'll add that as the cars become significantly different from on another, the relationship deteriorates.

[INTMD8]

I agree with a lot of what you are saying.  I'm not trying to say an 8 or 10 speed is the -ONLY- way and will make a 10 second car an 8 second car, but it does make a significant improvement.

Agreed that power curve plays a big part in how much it matters, very peaky/high rpm is going to need to stay in a narrower window.

Take the 213ci engine in my other car which makes peak power at 8350, remove the 4.35 final drive and close ratio box and replace it with a 2.35 and wide ratio box, it would be an absolute slug. (you won't realize the potential trap speed vs peak hp if you are going through the traps 4000rpm under peak)

The example was essentially the same car one year later.  Factory numbers, I have not dynoed them.

Another example is an LS2 corvette. Exact car and engine but 4 speed auto in 05 and 6 speed auto in 06.  6 speed auto is 1-2tenths 1-2mph faster even though the final drive went from a 2.73 in the 4 speed to a 2.56 in the 6 speed.

392 Challenger went from a 5 speed to 8 speed and was about 3 tenths 3mph faster.

The potential for quicker times is not always realized as much as the Mustang example that goes through the traps in 7th gear.

Hellcat goes through the traps at around 5000rpm in 5th gear as it has a 2.62 final drive.  With a relatively flat torque curve due to the positive displacement blower I wouldn't expect it to pick up much/any trap speed with a gear change vs a naturally aspirated car.

Agreed again it's hard to compare very different combo's.  (Like a top fuel car basically using the clutch as CVT).

As for your race, I don't know any of the details but the combinations I've seen pick up trap speed is a gear change that puts it through the optimum rpm through the traps. Like a 4th gen f-body with a cam, tight converter and 2.73. Go to a 3.73 and put it right at peak horsepower through the traps and it picks up several mph.

If it was 2.73 with a 4400 converter the difference would be less with a gearing change because the rpm difference through the traps would be less due to converter slip.

Would I bother putting a ZF8HP in a 60's Charger? Hell no, probably wouldn't bother trying to put it in anything but still will stand by the fact that more speeds can and in many cases does equal a measurable performance improvement.

[c00nhunterjoe]

A 213 ci 8350rpm peak power engine is not a very good comparison on a 2nd gen charger site.
The ls2 and srt392 comparison is more relative and i would like to know if those 2 runs were made at the same time at the same track? My car's mph will vary as much as 8 mph depending on what track i travel to. While experimenting with my car early on, i had 2.76s in it. I changed to 4.30s and my mph did not change, only my e.t.. runs were made the same day with gear swap done at the track.

[INTMD8]

A 213 ci 8350rpm peak power engine is not a very good comparison on a 2nd gen charger site.

It was a point in response to power curves/gearing obviously.

Please link me to forum members top fuel 2nd gen Chargers 

As for the 392 5 vs 8 speed it's been proven a billion times. Try google.

[flyinlow]

First ,sorry Metcoll did not mean to jack your thread.

So I can take away two statements;

If I input the weight of the .race car and it's Hp. The formula will give me the maximum mph trap speed I should see assuming I have an efficient power train ,tire and I drive it well.

If I I input the weight of the race car and it's trap speed. the formula will give me the minimum Hp. The engine makes.

[c00nhunterjoe]

A 213 ci 8350rpm peak power engine is not a very good comparison on a 2nd gen charger site.

It was a point in response to power curves/gearing obviously.

Please link me to forum members top fuel 2nd gen Chargers 

As for the 392 5 vs 8 speed it's been proven a billion times. Try google.

The top fuel reply was in direct response to your statements. That makes it relevant. Your claim of comparing the power curve of a small cube, narrow band high rpm engine to a b body mopar engine and drivetrain need is absurd. As to your 392 5 vs 8 speed. I see no back to back time slips of exact cars. I see no transmission dyno sheets from mopar dictating the hp used between those 2 engines. This is your claim, and your responsibility to prove. And you cant. If the 8 and 10 speed are the way to go, then the no budget, high dollar race teams would all be running them.

[INTMD8]

A 213 ci 8350rpm peak power engine is not a very good comparison on a 2nd gen charger site.

It was a point in response to power curves/gearing obviously.

Please link me to forum members top fuel 2nd gen Chargers 

As for the 392 5 vs 8 speed it's been proven a billion times. Try google.

The top fuel reply was in direct response to your statements. That makes it relevant. Your claim of comparing the power curve of a small cube, narrow band high rpm engine to a b body mopar engine and drivetrain need is absurd. As to your 392 5 vs 8 speed. I see no back to back time slips of exact cars. I see no transmission dyno sheets from mopar dictating the hp used between those 2 engines. This is your claim, and your responsibility to prove. And you cant. If the 8 and 10 speed are the way to go, then the no budget, high dollar race teams would all be running them.

My example is absurd but top fuel is relevant. I don't care what you believe. You asked for examples I gave them. If you don't want to believe it I simply do not care.

[c00nhunterjoe]

Ok, 3rd time. What is the horsepower consumption of the 5 speed vs 8 speed. And what were the exact track conditions of the 2 runs you reference,  but did not post slips on? Asking for validation of your claims is not absurd, yet you are getting angry. I have nothing to gain nor lose here. I beleive in facts, none of which you have produced.

[INTMD8]

Ok, 3rd time. What is the horsepower consumption of the 5 speed vs 8 speed. And what were the exact track conditions of the 2 runs you reference,  but did not post slips on? Asking for validation of your claims is not absurd, yet you are getting angry. I have nothing to gain nor lose here. I beleive in facts, none of which you have produced.

How would I know the power consumption? They are one year apart, not decades. I'll post some links later when I can get to my laptop.

[c00nhunterjoe]

2 completely different transmissions. Its your arguement, not mine. Like comparing a turbo 350 to a 4l80. Big difference. Also waiting on the time slips and weather conditions for the 2 cars quoted.

[c00nhunterjoe]

Given a brief google search as you suggested, the nag1 uses approximately 5% more hp to turn then the zf8. In your srt 392 example, thats 20 some horsepower... a pretty substantial difference which will account for your 1-2 mph difference between 2 identical cars as you stated, not the 3 extra gear difference. Parasitic loss is the answer to your claim in these scenarios.

[INTMD8]

Here is the problem with further effort on this conversation. If no matter what I say you want to drop the hammer on me what is the point? Gave examples of same car different trans now it changes to invalid because different trans. Really? If you keep raising the bar it's easy to see that you will teach a point I can't get to.

So to be real, obviously if we are comparing 5 vs 8 speed we are talking different transmissions. If that qualifies as not a valid comparison there's really nothing left to talk about.

Said in a different way, this would be more constructive if you were open to discussing the matter at hand instead of being on a mission to bury me.

So you want to talk about it great, but if anything I say or do is not considered or not good enough I'm good with agreeing to disagree.

[INTMD8]

Given a brief google search as you suggested, the nag1 uses approximately 5% more hp to turn then the zf8. In your srt 392 example, thats 20 some horsepower... a pretty substantial difference which will account for your 1-2 mph difference between 2 identical cars as you stated, not the 3 extra gear difference. Parasitic loss is the answer to your claim in these scenarios.

Not sure that's correct as you failed to link source as you placed so much importance on but the admittance of some advantage for the right reasons or not is a step in the right direction.

[c00nhunterjoe]

You said 2srt 392 challengers, identical cars but one with the nag1 and the newer with the fz8. That was your example. I googled the 2 transmisisons and sourced the relative improvement from the nag1 to the zf8. The difference justifies the 1-2 mph change between the 2 cars you posted about. I do not have dyno sheets. I have not tested the 2 cars. I googled the answer as you suggested i do. I am not trying to bury you. I continue to ask for real evidence to back up your claims and you continue to reply with google this and i heard about that. It does not help your arguement. You call me out for not posting offical sanctioned evidence yet every post and example of yours has been opinion?
   If you want to continue the discussion then im all for it. But if you wish to continue by sidestepping around giving factual answers then you are correct, its pointless and does not help your case.

[c00nhunterjoe]

From the manufacture of the transmission's website. 3% reduction in power loss over their previous 6 speed. Still researching the increase from the 5 speed. But i think the point is proven coming direct from the horses mouth. Even they specificly say that the parasitic loss reduction is their biggest improvement across the board.
https://www.zf.com/usa_canada/en_us/corporate/products_services_corporate/highlights_corporate/8hp_automatic_transmissions_corporate/index.html

[INTMD8]

Lmao, I've given several examples. If your search returned nothing relevant I can't imagine your inputs. Do you really think I will not be able to back this up? What you are requesting is not hard to find, pretty much common knowledge.

[metcoll]

Anyways what I was trying to get at since I have never dynoed this motor on an engine dyno,do you guys think this motor has 500 plus hp and tq..no tracks near by

[BSB67]

Anyways what I was trying to get at since I have never dynoed this motor on an engine dyno,do you guys think this motor has 500 plus hp and tq..no tracks near by

Based on 360 dynojet HP, no.

[BSB67]

If I input the weight of the .race car and it's Hp. The formula will give me the maximum mph trap speed I should see assuming I have an efficient power train ,tire and I drive it well.

If I I input the weight of the race car and it's trap speed. the formula will give me the minimum Hp. The engine makes.

You could interpret it that way considering that one is gross hp and the other is net hp.  However, based on my observations, I would say, generally speaking, statement number 2 gives something close to actual hp.  But you do need to make a reasonable adjustment for PS, alt, fan, full exhaust..., and that is likely the actual flywheel HP.

And statement number 1 is also generally true. (Remember, it's derived from empirical data), if you have good dyno data.  This is where I'm generally a skeptic.  I believe happy dynos are common.  That said, and in defense of engine dyno operator's,  they don't know what an engine/car owner does between the time that the engine leaves the dyno room to going down the track in a car.

Said differently, if you have a realistic engine dyno hp data, you don't screw anything up when you install the engine and make the car operational, statement 1 and 2 will generally show similar HP numbers.

And it is important to correct everything to std conditions, the best you can.

[c00nhunterjoe]

Lmao, I've given several examples. If your search returned nothing relevant I can't imagine your inputs. Do you really think I will not be able to back this up? What you are requesting is not hard to find, pretty much common knowledge.

You have given several opinions and statements about random cars and rough mph differences with no facts about the said cars you refer to in any statement. I provided the manufacturer's own data and website on the 2 different transmissions you refered to regarding a 1-2 mph difference in identical cars with the exception of the transmissions. Their efficiency data confirms the mph difference between the two cars you reference yet you dismiss the manufacture as irrelevant and still ramble on about it.

[c00nhunterjoe]

If I input the weight of the .race car and it's Hp. The formula will give me the maximum mph trap speed I should see assuming I have an efficient power train ,tire and I drive it well.

If I I input the weight of the race car and it's trap speed. the formula will give me the minimum Hp. The engine makes.

You could interpret it that way considering that one is gross hp and the other is net hp.  However, based on my observations, I would say, generally speaking, statement number 2 gives something close to actual hp.  But you do need to make a reasonable adjustment for PS, alt, fan, full exhaust..., and that is likely the actual flywheel HP.

And statement number 1 is also generally true. (Remember, it's derived from empirical data), if you have good dyno data.  This is where I'm generally a skeptic.  I believe happy dynos are common.  That said, and in defense of engine dyno operator's,  they don't know what an engine/car owner does between the time that the engine leaves the dyno room to going down the track in a car.

Said differently, if you have a realistic engine dyno hp data, you don't screw anything up when you install the engine and make the car operational, statement 1 and 2 will generally show similar HP numbers.

And it is important to correct everything to std conditions, the best you can.

Agree totally with the above.
As to the hp use of accessories,  the saginaw ps pump uses roughly 10-15 hp depending on the pressure output you have yours set at. A direct drive fan can eat 30+ hp at higher rpm, clutch fans in the 5-10. Alternators vary based on size and load, exhaust varies as well. Full through the tailpipes with freeflowing mufflers can still eat 15+ compared to open header and 18" collectors. Depends on case by case.

[INTMD8]

From the manufacture of the transmission's website. 3% reduction in power loss over their previous 6 speed.

3% reduction over the previous 6 speed not 3% of total engine output.  So if the old trans consumed 40hp the new one is 38.8.

[INTMD8]

Same car different trans. Certainly the manual doesn't consume more power than the auto.

And yet, traps 3.7mph faster with the 10 speed. 

If you still want to believe it doesn't matter, believe whatever you want.


https://www.motortrend.com/news/why-the-2018-ford-mustang-gt-automatic-is-so-much-quicker-than-the-manual/

[c00nhunterjoe]

Same car different trans. Certainly the manual doesn't consume more power than the auto.

And yet, traps 3.7mph faster with the 10 speed.  

If you still want to believe it doesn't matter, believe whatever you want.


https://www.motortrend.com/news/why-the-2018-ford-mustang-gt-automatic-is-so-much-quicker-than-the-manual/

Different final drive as well. It is about as close a comparison you can get, i will give you that. I have still seen identical cars run completely different times at the track side by side as far as mph goes. And even that article says in black and white that the transmission's extra gears are not the sole source of difference. The rear gears allow the mechanical advantage to change between the 2 cars. So again, comes down to the whole package, not justadding more gears. Also, why is a car trapping almost 120mph still in the 12s?

[INTMD8]

The bottom line is horsepower dictates the mph, not the transmission or rear gear ratio.

The rear gears allow the mechanical advantage to change between the 2 cars. So again, comes down to the whole package, not just adding more gears.

   I'm sorry, what's the bottom line again?    Yes I'm aware gearing influences trap speed.  (that would be trans and final drive) Thanks for playing.

[c00nhunterjoe]

The total package affects elapsed time. Common knowledge. Thanks for continuing to be an ass. Also explains why an 11 second car is only running 12s. I would bet there was launch control and traction control used on both cars thus pulling power on every shift of the stick car.. Pretty sad that a low 11 second car can only his mid to high 12s with almost 500 hp on tap. Thought that new 10 speed trans would help more but i guess not. Plenty of members on this site trapping the same mph with shitty 3 speeds and lower ets. You are clearly a troll, thus why noone else is even responding to you.

[c00nhunterjoe]

Anyways what I was trying to get at since I have never dynoed this motor on an engine dyno,do you guys think this motor has 500 plus hp and tq..no tracks near by

If you want bragging rights you could cheat the dyno. I would bet we could get 400 to the wheels for paper purposes. Drop the belts off the ps and alt. Remove the fan blade from the water pump. Swap the engine oil for some 0w20, dump the diff fluid and only run 1 qt for the dyno session, get the drivetrain good and hot before the dyno pull.

[INTMD8]

Instead of wanting to have a discussion I'm told I'm an asshole that doesn't know what he's talking about.  As for my attitude, don't be a prick out of the gates and I'll respond in kind.

The entire argument was that gearing affects trap speed to which you repeatedly disputed, then turn around and say "well, the gearing is different which allows mechanical advantage to change between the 2 cars"

Well no shit Chet!  Thanks for repeating what I've said all along as if this is some kind of news to me. 

Stock Mustang on a stock radial, should not be hard to figure out that it could ET better on a tire. Both cars are identical except for the trans/gearing. I'm not Ford's brand ambassador, simply using it as yet another example to prove you wrong.

So again to summarize, you argue gearing doesn't matter then when viewing proof of .5 second et and 3.7mph you turn around and say "well they are geared differently" and "I thought it would make a bigger difference".

Sorry but you are completely full of it.

[c00nhunterjoe]

Instead of wanting to have a discussion I'm told I'm an asshole that doesn't know what he's talking about.  As for my attitude, don't be a prick out of the gates and I'll respond in kind.

The entire argument was that gearing affects trap speed to which you repeatedly disputed, then turn around and say "well, the gearing is different which allows mechanical advantage to change between the 2 cars"

Well no shit Chet!  Thanks for repeating what I've said all along as if this is some kind of news to me. 

Stock Mustang on a stock radial, should not be hard to figure out that it could ET better on a tire. Both cars are identical except for the trans/gearing. I'm not Ford's brand ambassador, simply using it as yet another example to prove you wrong.

So again to summarize, you argue gearing doesn't matter then when viewing proof of .5 second et and 3.7mph you turn around and say "well they are geared differently" and "I thought it would make a bigger difference".

Sorry but you are completely full of it.

You like to manipulate statements to fit your agenda. Never seen a stick car out et an auto in any way shape or form on stock radials tires. No kidding the auto et's considerably better. The traction control will be cutting power and fuel on every shift in the stick car when the tires break loose. . What happens when you cut power? Oh, thats right, you lose mph. But thats irrelevant because you said so.

[c00nhunterjoe]

Another perfect example when comparing stick cars. This is a friend's shelby gt500 stick car. Nowhere near stock. Pulley, cams, program, headers exhaust... you name it, its on it.... yet look at the run when the computer is allowed to control traction and stability... whats that you say? Its slower then stock??? How could that be? A 12.40 out of a shelby? At 125mph no less.. So in your arguement, yup, installing the modern auto would drop almost 3 seconds off the et and add several mph, making your arguement technically true, yet still laughable. You would make a good politician.

https://youtu.be/AWjqNlJPZPs

[INTMD8]

You would make a good politician.

Amusing as you're the guy who did a complete 180 here.  Also love how you felt like you found the holy grail with trans efficiency difference before realizing you had no idea what you were talking about.

As for the stick mustang spinning and cutting power you're straight up making shit up.  You think the auto doesn't have torque management or have the ability to spin on a shift and get reeled back in with as you finally understand -even more mechanical advantage-?  Yeah the stick car is putting less torque to the tires, has the same exact tires and yet it's the one with the traction problem.  Graph of acceleration proves that is not the case.

Enough proof has been posted for you to essentially be quoting my remarks in your defense and you still don't realize you're backpeddling?

This was too easy but I'm growing bored of replying to your moving target of absolute nonsense so I'm out.    

[c00nhunterjoe]

I made up the video with the shelby? Your best arguement to date i must say. The holy grail was found in the last 3 words of your post.

[1974dodgecharger]

Cant you just get it on the dyno instead of guessing  I know the dyno scares so many people because they expect XXX amount of power and get way less.  So they get mad.....I been on the dyno many times and tune my own car and never gotten mad  lol....take it as a learning lesson and do better next time and stop guessing what is RWHP vs engine dyno blah blabh blah