Engine mods with no gain in performance?

[Inspector71]

My question was actually posted on a sportscar forum where I am a member. I can't post it there again because the answers I received made no sense. My question was, by adding headers, an improved induction system, and improved exhaust system this car's engine should be able to generate up to 50 more horse power. Other mids would take it up even more. So, I asked, how much would this improve 0 to 60 times, top speed, and so forth. The answers from other members was the mods would greatly improve horsepower but would not alter the standards of measures I listed above. I couldn't believe what I was reading. So, I asked, if all those mods substantially increase horsepower but have no impact on performance, why waste the money? I never got an answer.
I have a 68 Charger that will eventually receive a stroked 383 with headers aluminum heads, and other mods and I can't believe all that would make no difference in performance. Am I missing something here?

[c00nhunterjoe]

More modifications will mean more power yes, giving the potential for better performance. There are 2 factors that ultimatly limit your performance irregardess of your horsepower: traction and the driver

[ChgrSteve67]

Its all derived from a power to weight ratio.
More horse power and torque will affect your performance.

Here is a 0-60 calculator you can play with.
http://www.060calculator.com/

Here is a 1/4 mile calculator
http://robrobinette.com/et.htm

[HPP]

My question was, by adding headers, an improved induction system, and improved exhaust system this car's engine should be able to generate up to 50 more horse power. Other mods would take it up even more.

50 horses as proven out on a dyno or drag strip pass or 50 horses by manufacturers claims and adding up each component's advertised maximum? One will show a change, the other is probably overstated by 25 horses.

So, I asked, how much would this improve 0 to 60 times, top speed, and so forth. The answers from other members was the mods would greatly improve horsepower but would not alter the standards of measures I listed above. I couldn't believe what I was reading. So, I asked, if all those mods substantially increase horsepower but have no impact on performance, why waste the money? I never got an answer.
I have a 68 Charger that will eventually receive a stroked 383 with headers aluminum heads, and other mods and I can't believe all that would make no difference in performance. Am I missing something here?

Influences to the cars ability to accellerate, top speed, 0-60 also have variables of drive ratios, drive train loss, traction coefficient, drag, air density, driver skill and others. It could potentially be faster, but not by a huge amount, if at all. What is the base line to start with as well. 50 horses on a 200 horse mill is a lot. On a 500 horse mill, not so much.

So why waste the money if it doesn't change performance, dunno, thats up to each individual. Typical answers may be "because I want to, I like the way it looks, "I" think it performs better."

[BSB67]

What exactly is your question, as it is not clear.  Is the question....1) "if I add 50 hp, what should I expect in quarter mile performance improvement?", or  ....2) " If I added headers, better exhaust, and induction system, what would be the quarter mile performance improvement?" These are completely different questions.

With some qualifications, the answer to #1 is easy.  #2, not so much.  For #2, the details of what you have, and what you change could result in anything from no gain to possibly 50 hp.  Therefore, assuming that those changes will net 50 hp improvement is not a great assumption.

Have you made this change, and do you have some track data?

[Inspector71]

Let me try again because apparently I my question was confusing. I belong to another forum for sports cars. The forum features many adds for performance modifications. The forum members post pictures of their cars and various levels of modification. The modifications range from mild (intake/exhaust modifications) to more radical from turbos to super chargers. Obviously each level of modification costs more. Naturally, I wanted to understand if each level was worth the work and expense. In other words, how did the modifications translate into improved performance? Simple standards to start with are 0 to 60 times, quarter mile, top speed. I asked a simple question on this forum, what were the changes in those measurements based on each level of modification? The answer was none. I couldn't believe that such modifications resulted in no change in performance, asked for clarification, and was told by forum posters, none. I asked why the work and expense for nothing and received no answer. I have played around with cars for years and find this hard to believe. I hope this makes more sense.

[myk]

I find it hard to believe that there was no effect on performance; parts will either improve or hinder performance based on how well thought out the parts and installation are, and power numbers should reflect that more or less...

[440]

This question seems open ended and subject to many variables. I wouldn't necessarily call it levels of modification but more a "package."

Changing exhaust or the way an engine exhales won't make a difference if the engine can't inhale.

Part "A" might not work without part "B". A big cam could likely hurt performance until correct heads are added etc.

Power to weight ratio is the best measurement of performance in my opinion.

[John_Kunkel]

"Back in the day" I ran a '63 Dodge Max Wedge car. At first it was basically stock so I tossed the factory cast iron exhaust manifolds and installed a set of fender well headers; this gave better breathing and eliminated 75 pounds from the front of the car but the change in ET was zero. The reason....traction, or lack of it because of the mandated 7" slicks.

[firefighter3931]

Increasing power will make the car go faster (MPH) but that might no translate into better elapsed times due to other considerations such as traction and weight transfer (suspension)

If the changes net a higher MPH at the track it is making more power, period ! 

Here's a good thread on a 383 build with incremental engine modifications and track results to back up those improvements. 

http://www.dodgecharger.com/forum/index.php/topic,91213.0.html


Based on your comments regarding the responses from the other car forum it's be safe to say those guys don't know much about cars and even less about making power ! 

As mentioned above ; 50hp on a 300hp build will be quite noticable but on a 500hp build not so much. In either case the increased power will show up on the timeslip but on the higher HP build the improvement will be more modest.



Ron

[FLG]

Agree with all above..just to add.

You need to think of an engine, transmission, differential and everything that goes in-between as a whole.

Everything needs to work together.

You need to think about what your going to do with the car, and build it around that.

Than you need to match the cam and heads, if its a street car you need some idle quality and possibly enough vac to run power brakes, you also need to make sure your cams power band comes in correctly with the gears your going to be running. You also need to have the correct size heads, if the ports are too large your going to lose velocity and thus power, too small and she wont breath very well.

If your running a auto you than need to further this by ensuring the flash on the converter comes in with the power band of the motor.

You need to have the correct size headers and exhaust to further match this, if the headers are too big your going to be losing power (specifically torque), exhaust is also important...a well designed exhaust with an X-pipe will help.

So all in all, its not as simple as adding bolt on's and expecting huge gains without doing further work. There are some bottle necks that will help out (headers, x-pipe) but on a stock 318 id expect small gains, on a hot 440 those gains will be much more.

[BSB67]

Okay.

A pretty accurate general rules of thumb for a 3500 lb to 4000lb, 13 second car: 10 hp = 100 lb = .1 second = 1 mph,  and still fairly accurate well into the 12s.  

If it is a street car that can spin the tires off the line, the 60ft does not change with hp as it is dependent on the traction, not the power.

The increase in power is directly tied to the increase in mph.  If the 60 is the same, it will also produce a lower et.  If you add power, but you 60 ft time is worse due to tire spin, the mph will still go up, but et will likely get worse.  If you remove 100 lbs from the car, the et/mph will improve the same as if you added 10 hp.

Adding additional hp equipment that does not generate a better mph can be due to several factors:  1) The track DA between the two test sessions is different, 2)the wrong or mismatched parts were added or installed incorrectly, 3) The tune is incorrect with the new equipment, 4) inconsistent driving technique, 5) something else with the motor is going south.

A muffler gone bad, or slightly inadequate fuel pressure will take 3 or 4 mph out of a car instantly.

If you add 10 hp, and the track atmospheric conditions are the same, the car will mph better.

[HPP]

Okay, maybe we need to dissect this piece by piece.

Let me try again because apparently I my question was confusing. I belong to another forum for sports cars. The forum features many adds for performance modifications.

Yes, many forums accept sponsorships from companies to pay for expenses. Not all of them out their operate as cleanly as DodgeCharger.com. with minimal outside influence. Can this impact readerships, membership, postings and other traffic, yes. Does that mean these companies have "pumpers" logging in to push their products. Maybe, I can't say for certain, but it is a possibility.

The forum members post pictures of their cars and various levels of modification. The modifications range from mild (intake/exhaust modifications) to more radical from turbos to super chargers. Obviously each level of modification costs more. Naturally, I wanted to understand if each level was worth the work and expense. In other words, how did the modifications translate into improved performance?

Okay, I think that is a reasonable place to start. Certainly they have a right to be proud of their rides.

Simple standards to start with are 0 to 60 times, quarter mile, top speed. I asked a simple question on this forum, what were the changes in those measurements based on each level of modification? The answer was none.

Okay, this single action called them out. The key to being able to communicate the change resulting from modification implies that you have created a baseline on your car with which to gauge all future changes. Lets call this baseline X. Odds are that few, if any, if them ever did this. They simply read the magazine articles, bought in to the marketing hype and by adding up all the manufacturer claims said they added Y amount of power and now had X+Y amount of power.  Without the baseline, there is no way they could validate whether they made more power or not. I'd also venture a guess to say they did not test as each change was added, but they simply ran up teh credit card then spent a couple weekends changing out parts. Again, a situation that makes changes difficult to track because so many variables we altered at one time. I also have no idea where you are at or these other posters were located. Physical and density altitude have a tremendous impact on a cars performance. If they did not adjust for these changes to create an normalized, then again we have faulty data. Of course it is all moot if you never knew what the base lines was to begin with.

I couldn't believe that such modifications resulted in no change in performance, asked for clarification, and was told by forum posters, none. I asked why the work and expense for nothing and received no answer. I have played around with cars for years and find this hard to believe. I hope this makes more sense.

Yup. If you don't know something, either keep your mouth shut and make up stuff. You already called their bluff, they weren't going to make up more lies. I'd say leave it at that.

[Chryco Psycho]

Spending your $$ smart is the key , you can blow a lot of cash with little result , often advertizers will sell their products as the next best thing when the truth is far different . case in point I spent a lot of time porting a set of 452 castings , my friend decided the Eddy heads would be the hot ticket . We ported the Eddys, spent over 2 k , had to fly cut the pistons to clear the valves as they are not positioned exactly the same , had to re-fit 2 tubes on the headers for the slant plugs , the rockers didn't over the valve tips properly either so we had to shim up the rockers .
Net gain using a RW dyno , the same dyno before & after was 305 RWHP with Iron heads , 308 with Eddys , hardly worth the 2k+ spent for 3 hp .
Talking with people who are not selling anything but have the experience first hand will get you a long way .

[Cooter]

This question seems open ended and subject to many variables. I wouldn't necessarily call it levels of modification but more a "package."

Changing exhaust or the way an engine exhales won't make a difference if the engine can't inhale.

Part "A" might not work without part "B". A big cam could likely hurt performance until correct heads are added etc.

Power to weight ratio is the best measurement of performance in my opinion.

Exactly...No one is gonna "Guarantee" you see a "Worthwhile" performance gain from anything you buy, or install.

unless you have the $500/day for dyno time, you will not know how much power/performance those brand new hedders you just paid $1000.00 for will net you in performance.

[Inspector71]

Let me see if I can try one more time. The responses are excellent and reveal and incredible degree of knowledge when it comes to not only performance but why various parts perform the way they do together. Their synergy. I get all that but to some degree, the answers are a little "over-engineered" in relation to what I was asking. Again, I don't want to offend anyone because I want the opportunity to continue to pick your brains about how best to set my car up and you folks know your stuff. If you can suffer me a little longer, let me explain it this way. The Forum is for fans of the new Nissan 370. The mods discussed were not those discussed and promoted by the manufacturers of various performance components but of the car owners themselves. Just like this forum, they have thread after thread in which they discussed adding cool air intakes, headers, changing exhaust systems, and mufflers. In other words, fairly standard bolt-on's. I simply asked how these parts, and they are not cheap, improved the performance of the 370Z. The answer I received was more horsepower. Hey, who doesn't want more horsepower, right? So next I asked how that translated into increased performance using standard yardsticks like 0-60 times, top speed, and quarter mile. Since I am not interested in rally racing, I kept to those measurement protocols. The answer I received was "No difference." I'll be the first to admit I am far from being an authority and have managed to corner the market on ignorance in many areas but it made no sense to me. So I tried asking the question several different ways and got the same answer. Then I asked what would be the sense of spending past $3K for no more performance? I could drive the car stock and save the money. A few other people asked the same question and one poster said it would sound better. At that point I gave up and was hoping you all could help.

[FLG]

You wont offend any of us, we'll probably offed you first 

Cold air intakes, mufflers, and headers on such a car honestly is most likely for "sound" more than anything, probably minor hp gains but nothing a butt dyno would probably notice.

Add those things up and throw in a tune...yes you will feel and see a difference without a doubt.

The car has 332hp at 7k and 270ft/lbs at 5200rpm

In all honesty your probably looking at maybe 5-10hp? maybe a bit more from exhaust and intake...and knowing how people are "bigger is always better" throwing headers on such a car probably hurts your torque...theres hardly any to begin with down low and at 3200lbs curb weight the car isnt exactly light.

Id say for that car its best bet is intake, exhaust, and a tune. Leave the manifolds alone.

[HPP]

Heck, on that car I seriously doubt the aftermarket has come up with any parts that are going to seriously outperform the factory stuff in street applications. On top of that, these guys were doing all the traditional modern "hot rod" hop ups that are are still in the realm of folklore. That car is still way too new with too small an "installed base" to really science out the changes these shadetree guys are working on. Even the LS chevy guys will tell you that on their modern engines, there are probalby only a few headers designs out of a hundred that are actually better than stock and mufflers, exhaust, and intake stuff only yields results when you start pushing much higher power levels and working with things as a system rather than a few bolt on parts.

I agree with FLG, they are buying into a sound and image and THINKING they added 50 horses cuz marketing said they were.

[Paul G]

So I tried asking the question several different ways and got the same answer. Then I asked what would be the sense of spending past $3K for no more performance? I could drive the car stock and save the money. A few other people asked the same question and one poster said it would sound better. At that point I gave up and was hoping you all could help.

I think you already have the answer to your own question here.

I believe when the aftermarket "go fast" parts suppliers decide on what "additional horsepower number" to put on a specific part, they do it like this; They build out an engine adding all the known "go fast" goodies. Dyno the engine, then remove say, a larger throttle body, and put the stock one back on. Dyno the engine again and loose 15 horsepower, so there it is, you gain 15 horsepower with our bigger throttle body. But, not truly the case. If you added that same throttle body to an otherwise stock engine you would see almost no gain. No gain without all the rest of the go fast goodies to go along with it.

So, adding up the advertised gains of each part by itself, or just a couple of them, is not going to net you any where near the advertised gains. Not without building out the engine to the complete package.

Lots of people spend lots of money on "go faster" parts to find they actually went slower, but sounded better doing it! And looked so cool on cruise night.

[Challenger340]

These are just my opinions only.....
I think the problem with discussing individual modifications, relative to HP increases that "each" should deliver towards a TOTAL gain, is an absolutely MOOT POINT...
because none can be determined or guaranteed as "positives", or "negatives" unless how they are working together is a KNOWN ?
The COMBO works together !

The DEFICIENCIES in an Engine combination, must be addressed KNOWN first, that can then be addressed for a GAIN, without simply throwing parts where no gain is needed, or can be taken ADVANTAGE of by the Existing parts.....
Lets try explaining it a different way....
If an engine has sufficient camshaft / exhaust /etc., etc., to be able to "efficiently" utilize 300cfm Heads, what is the point installing 350 cfm Heads if the extra 50cfm can NOT be used by the engine efficiently ?
Indeed,
many times, this exact rationale gets employed from an uneducated standpoint...only to find out later, that performance stays the same, or even DROPS due to a drop in port velocity and A/F fuel quality.

Good case in point offered above about a guy listening to bad advice from media and buying Eddy's as "better".
Better at what ??
IMO,
obviously here....
the Heads were not the problem, and either the 452 Heads were Flowing equal to the Eddys...
or,
if the Eddy's were Flowing more, the Engine/parts combo could not take advantage of the extra Flow ?
Either way....IMO,
it could be misleading to think Eddy's are no good ? or conversely, that ported 452's are better ? unless the comparison criterion data is known, ie; actual Flow data on BOTH Heads, and WHAT the compressor underneath could UTILIZE efficiently for the comparison on THAT combination of parts?

IMO,
Any modifications to an engine, must improve "weaknesses" in the combination, without detracting from the "strengths" already present, or the net gain, may be nothing.
Therefore, the particular Strengths and Weaknesses of a  Engine combination must be a known, from either experience or data, BEFORE parts are thrown at an Engine Combination.

[Dino]

Apples and oranges

The 370Z is already a high(er) performance car, a few bolt ons will more likely mess up the engineers tuning efforts instead of making it go faster.  I'm sure a lot of those guys spend a bunch of money and came out with a slower car, not very noticable I'm sure but the dyno would show it.  I don't think I'd spend a few grand to have a better sound, better being objective by the way...

Now on a not so efficient dinosaur of a 383, there's lots of goodies out there to make it run better, faster, cleaner.

You WILL be able to get that 383 kicking butt left and right and you WILL see a great improvement in 0-60 and 1/4 mile times.

If you need to pick a place to get the better engine related answers, you may wanna stick around here!

[HeavyFuel]

Let me see if I can try one more time. The responses are excellent and reveal and incredible degree of knowledge when it comes to not only performance but why various parts perform the way they do together. Their synergy. I get all that but to some degree, the answers are a little "over-engineered" in relation to what I was asking. Again, I don't want to offend anyone because I want the opportunity to continue to pick your brains about how best to set my car up and you folks know your stuff. If you can suffer me a little longer, let me explain it this way. The Forum is for fans of the new Nissan 370. The mods discussed were not those discussed and promoted by the manufacturers of various performance components but of the car owners themselves. Just like this forum, they have thread after thread in which they discussed adding cool air intakes, headers, changing exhaust systems, and mufflers. In other words, fairly standard bolt-on's. I simply asked how these parts, and they are not cheap, improved the performance of the 370Z. The answer I received was more horsepower. Hey, who doesn't want more horsepower, right? So next I asked how that translated into increased performance using standard yardsticks like 0-60 times, top speed, and quarter mile. Since I am not interested in rally racing, I kept to those measurement protocols. The answer I received was "No difference." I'll be the first to admit I am far from being an authority and have managed to corner the market on ignorance in many areas but it made no sense to me. So I tried asking the question several different ways and got the same answer. Then I asked what would be the sense of spending past $3K for no more performance? I could drive the car stock and save the money. A few other people asked the same question and one poster said it would sound better. At that point I gave up and was hoping you all could help.

Help with what, dude?

Okay...let's see if I got this, you've reworded the same grip three times, not gotten the answer you want from the many knowlegable motorheads from this sight, so you just keep trying.

Let me give it a shot, even though I don't know squat about making HP.

THE GUYS ON THE OTHER FORUM DON'T KNOW SHIT, AND YOU SHOULD IGNORE THEM.  Mods ALWAYS equal measureable horsepower gains!

There.  Are you happy now? 

[FLG]

Let me see if I can try one more time. The responses are excellent and reveal and incredible degree of knowledge when it comes to not only performance but why various parts perform the way they do together. Their synergy. I get all that but to some degree, the answers are a little "over-engineered" in relation to what I was asking. Again, I don't want to offend anyone because I want the opportunity to continue to pick your brains about how best to set my car up and you folks know your stuff. If you can suffer me a little longer, let me explain it this way. The Forum is for fans of the new Nissan 370. The mods discussed were not those discussed and promoted by the manufacturers of various performance components but of the car owners themselves. Just like this forum, they have thread after thread in which they discussed adding cool air intakes, headers, changing exhaust systems, and mufflers. In other words, fairly standard bolt-on's. I simply asked how these parts, and they are not cheap, improved the performance of the 370Z. The answer I received was more horsepower. Hey, who doesn't want more horsepower, right? So next I asked how that translated into increased performance using standard yardsticks like 0-60 times, top speed, and quarter mile. Since I am not interested in rally racing, I kept to those measurement protocols. The answer I received was "No difference." I'll be the first to admit I am far from being an authority and have managed to corner the market on ignorance in many areas but it made no sense to me. So I tried asking the question several different ways and got the same answer. Then I asked what would be the sense of spending past $3K for no more performance? I could drive the car stock and save the money. A few other people asked the same question and one poster said it would sound better. At that point I gave up and was hoping you all could help.

Help with what, dude?

Okay...let's see if I got this, you've reworded the same grip three times, not gotten the answer you want from the many knowlegable motorheads from this sight, so you just keep trying.

Let me give it a shot, even though I don't know squat about making HP.

THE GUYS ON THE OTHER FORUM DON'T KNOW SHIT, AND YOU SHOULD IGNORE THEM.  Mods ALWAYS equal measureable horsepower gains!

There.  Are you happy now? 

That is not true, mods do not = hp or tq

Mods that work with the rest of the combination will lend themselves to adding or freeing up hp/tq but bigger does not always equal better and some mods will cause a loss of hp/tq sometimes if they do not work with the rest of the combo.

[HeavyFuel]

Let me see if I can try one more time. The responses are excellent and reveal and incredible degree of knowledge when it comes to not only performance but why various parts perform the way they do together. Their synergy. I get all that but to some degree, the answers are a little "over-engineered" in relation to what I was asking. Again, I don't want to offend anyone because I want the opportunity to continue to pick your brains about how best to set my car up and you folks know your stuff. If you can suffer me a little longer, let me explain it this way. The Forum is for fans of the new Nissan 370. The mods discussed were not those discussed and promoted by the manufacturers of various performance components but of the car owners themselves. Just like this forum, they have thread after thread in which they discussed adding cool air intakes, headers, changing exhaust systems, and mufflers. In other words, fairly standard bolt-on's. I simply asked how these parts, and they are not cheap, improved the performance of the 370Z. The answer I received was more horsepower. Hey, who doesn't want more horsepower, right? So next I asked how that translated into increased performance using standard yardsticks like 0-60 times, top speed, and quarter mile. Since I am not interested in rally racing, I kept to those measurement protocols. The answer I received was "No difference." I'll be the first to admit I am far from being an authority and have managed to corner the market on ignorance in many areas but it made no sense to me. So I tried asking the question several different ways and got the same answer. Then I asked what would be the sense of spending past $3K for no more performance? I could drive the car stock and save the money. A few other people asked the same question and one poster said it would sound better. At that point I gave up and was hoping you all could help.

Help with what, dude?

Okay...let's see if I got this, you've reworded the same grip three times, not gotten the answer you want from the many knowlegable motorheads from this sight, so you just keep trying.

Let me give it a shot, even though I don't know squat about making HP.

THE GUYS ON THE OTHER FORUM DON'T KNOW SHIT, AND YOU SHOULD IGNORE THEM.  Mods ALWAYS equal measureable horsepower gains!

There.  Are you happy now? 

That is not true, mods do not = hp or tq

Mods that work with the rest of the combination will lend themselves to adding or freeing up hp/tq but bigger does not always equal better and some mods will cause a loss of hp/tq sometimes if they do not work with the rest of the combo.

I was giving the guy a little crap.....my comments were......wait for it..........sarcasm.

[FLG]

I guess i was half asleep, reading it now i get it