What is REAL horsepower?

[skip68]

I'm building a 500-525 horse 446 motor.(That's what the shop says) And I've heard alot of guys talk about real Horsepower. Does this mean I'm not going to have it all??? Help me understand please!!! THANKS.    Chuck.................................

[firefighter3931]

There's real HP and there's theoretical HP.   Real horsepower is measured on an engine dyno and can be quantified with actual numbers. A lot of folks think their engine is making 500hp when in reality it's making around 400 or so. A 500hp 440 is a pretty stout combo and that means a very good set of heads...max ported iron or aftermarket aluminum castings, a solid cam with a lot of duration, big headers and a single plane intake manifold and 800cfm carb. If the shop claims it to be a 500+ hp build have them dyno the engine for you ; otherwise it's speculation at best.

Ron

[Ghoste]

And some are going to say it's chassis (rear wheel measured) as opposed to an engine (at the flywheel) dyno.

[skip68]

Ok thanks guys, I've got Mopar 509 cam, Roller rockers, 850 Holley, Ross Race pistons,Dart custom cast heads w/port work,Single plane torker intake I beleave, and ect... OH, I might be wrong on the carb but my friend said that's what it looks like. Well thanks for helping me with a dumb question .... Chuck......................

[Ghoste]

That wasn't a dumb question at all.

[skip68]

Yah I know, but I'm starting to learn more about cars a little late in life (36yrs) to some of my friends. They were playing with cars while I played the music scene. I've been bagged more than groceries. I've always paid for work done to my cars but I'm trying to build my 68 myself. Well, ok not the motor but what I can. It's something I really want to do so I can take more pride in it. And yes, I do get dirty. But I enjoy it and sometimes I think I should know more than I do. THANK GOD for this site, I can get help and an education minus the bagging THANKS,        Chuck......................

[cudaken]

 I kind of started the real HP stuff from a posting about 2 months ago. But Ron pretty much summed it up. Thread was about adverstised HP (from Ma Mopar) vs what they really made.

I am not a big fan of the 509 cam any longer. Are your Roller Rockers adjustable? If so I would look at the MP 528 soild cam, P4120659. Pulls way better at lower RPM's and reeves like hell. If you have not bought the 509 you can have mine if you live close by. You have to help pull it, and drink some Cam 2 as well.

What kind or roller rockers do you have anyway? If they are made by C A T throw them away.

                     Cuda Ken

[skip68]

Hey Ken, Got the 509 last week at the summit store on a Reno trip. My rockers are the crane gold series, adjustable? I don't know. Sorry man, I've got it all written down somewhere Thanks for the offer though. I was going to go with the eagle cam but my mechanic talked me into the mopar 509. It should run just fine for my needs he says. So I guess I'll see. But if you still need me to take out your cam Start the BBQ, and if I can get there in 20 I'll get'er done. Thank you sir, Chuck.............

[cudaken]

 If you mean 20 hours and doing the Cannon Ball Run, better have 2.76 gears, wing and a nose Send the 509 back and get the 528 stick!

Your mechanic is propley right, will work and run just fine. I don't think you are looking for fine! I have drove a 440 with the 528 stick and last thing it was, was fine! It was F--king great. I have the 509 in my Runner and it is the worst cam I have yet to run. Now, if my 383 was bulit like your 440 I may not be saying this. But the 440 was bulit like my 383 and beside the extra C I there was way more driffreces than the 57 C I should have made.

509 does the following well.

1 Sounds like a can full of rocks at idle and will scare off most at the stop light.
2 Make power out the ass after 3500 RPM's to 6000 where I back off.

Weak point's. Under 2500 it is a dog, need to pull gear to move in traffic.

528 Cam
1 Starts making power at 2500
2 Pulls like hell to 6500 PRM's
3 More foot pounds when you need it on the street.

528 Weak points?
1 Sound's way milder at idle than the 509 cam.
2 Need to adjust the rockers every 5,000 to 10,000 miles.

Ask you mechanic about the 528 cam. If he knows Mopar I think he will say it is a great cam as well.

                                         Cuda Ken

[skip68]

I'll ask if he's put it in yet. If not, then I'll try to grab a 528 then. I hope I get my real HP numbers at 500 give or take.   Thanks CudaKen,  Chuck.........................

[Chryco Psycho]

Hp is tough , Ron has the best description , but even that will vary , different dynos will give different #s , there is also gross HP exaggerated by the factories , net Hp which is more realistic & was supposedly engine HP at the flywheel from the fractory &   dyno proven hp at the crank & dyno Hp at the wheels
I had a customer come to me with a 440+6 engine with a claimed 450 RWHP garanteed by the builder........ it got 205 at the wheeels on a Mustang wheel dyno my customer went back & asked where they put the other 1/2 of the engine , I built a similar engine for a different customer & hit 312 RWHP on the same Mustang dyno & it has stock intake heads & exhaust manifolds

[cudaken]

 As far as the real 500 HP, well more than likely you don't really want it in the long run. 500 HP breaks stuff fast, like the car bodys!

What kind of ET have you ran? Shit happens fast and burtal at 500 HP. Your body is not stock right?

                                                  Cuda Ken

[firefighter3931]

I had a customer come to me with a 440+6 engine with a claimed 450 RWHP garanteed by the builder........ it got 205 at the wheeels on a Mustang wheel dyno my customer went back & asked where they put the other 1/2 of the engine , I built a similar engine for a different customer & hit 312 RWHP on the same Mustang dyno & it has stock intake heads & exhaust manifolds

Yep, it just goes to show that the combo of parts is EVERYTHING. Vegas Mike just went through the same thing with a poorly matched combo that ran like a dog....it's making very good power now with a little tweaking.  

The key is the camshaft.....too big and it murders the bottom end power. Fwiw, i'm not a fan of the 509 in a heavy street car.   Ken is right on the money with the 528 solid recommendation.  

Ron

[Runner]

the 528 will be a noisy cam though.

[firefighter3931]

the 528 will be a noisy cam though.

Good point Mike. I'm sure we could come up with a nice tight lash Comp grind that would perform just as well.  

Ron

[skip68]

Never ran at the track, but will give it a try. As for the car, I'm adding the frame supports to stiffin up the car and, I'm not hard on cars. I'll push it but not to the point of abuse. And with the looks of this info I've got a feeling my motors going to be in the 400 to 450 hp range Who knows, I might get lucky We will see, I'll get it on a dyno sooner or later...........Chuck.................................

[Ghoste]

Ahhh, screw the dyno.  Until they can accurately measure fun per minute, there's only one number that counts... e.t.!

[Runner]

a dyno should be used to get the tune up right. sometimes a fair bit of power is left on the table by not optimizing the tune. i wish we had a wheel dyno close, because id be using it.  the closest one is 110 miles from me, the car still might see that dyno at some point.

[Ghoste]

Oh I agree absolutely for tuning.  Don't misunderstand that post at all.  I just think that we often get too hung up on the final number when the important thing is the change in numbers as you alter engine characteristics.

[G Force]

My engine builder stated my 440 -6 would produce just over 500HP. When the rebiuld was finished and the car didn't perform to my expectations I brought it to a Mustang dyno, It produced 266 HP at the rear wheels. I am not sure what pecentage is lost throught the drive train ( if someone knows please post it) but I know its not that much!  Now after some months of work with some dyno tuning my car produces 316 HP ( is this a good number?) at the rear wheels. Is there still More ?? I don't know, How would I know??

[Blown70]

My engine builder stated my 440 -6 would produce just over 500HP. When the rebiuld was finished and the car didn't perform to my expectations I brought it to a Mustang dyno, It produced 266 HP at the rear wheels. I am not sure what pecentage is lost throught the drive train ( if someone knows please post it) but I know its not that much!   Now after some months of work with some dyno tuning my car produces 316 HP ( is this a good number?) at the rear wheels. Is there still More ?? I don't know, How would I know??

I have heard # of loss up to 20% in the drive line.  This can be some what dependent on how well components of the drive line are working.  Most people worry about the flywheel forward and do not do enough to the flywheel back IMO.

316 I personally do not think is bad a the wheel,  I am willing to bet you could get slightly more again however depends on what you are using the engine for.

Tom

[cudaken]

 On a rear wheel dyno many things come into play. Rear gears, tires sizes (slipping and height) all effect the HP figuer. Dynos are for tunning for best HP and that is it. There is only one ture way to test what you have and it is 1320 feet long. So me a dnyo slip that says you have 350 Rear Wheel HP I would ask then "do you have a ET slip from the track"? No traction no action, but that is a driffrent posting.

For what ever reason (Car Mag's) 500 HP is the magic number people think they need to shoot for. Yeah, sound real cool for bragging rights, but engines like to break stuff at that range. Tran's, drive shaft's, rear ends and yes the bodys if you hook well and stock. I got to crack the windsheild in my Runner thanks to slicks, SS springs and snubber. Hum, need to replaces that some day, only been 20 years more or less.


  Skip68, the subframe connectors smartest thing you have posted about so far. ( I know it sounds like a smart ass comment but was not). They will make your car handle better, feel tighter and over all make it fun to drive.

But a real 500 HP, better get depends (dippers) good life insurances and $40,000.00 stated value policy on the Charger.

I would still look at the 528 cam, just work your way into the power. We don't need another Charger or owner wrapped around a pole.

                             Cuda Ken

[skip68]

Thanks CudaKen. No poles or trees for me. The street is not a race track to me so I'll be careful. I'll talk to the mechanic tomorrow and see if cam is in yet. If not, then I'm going with the 528  NOW, as to the subframe connector coment, I've heard alot of talk about how they stiffin the cars up, improve handling and help with body flex. So I figured that's a smart thing to do. I've read alot of your post, and I'm not trying to kiss ass, BUT I'm getting an education and appreciate all the helpful advice    Once again thanks for your time. Skip68...................

[Chryco Psycho]

316 is good for the Combo , the Mustang loses more power 316 would be close to 500 Gross hp at the flywheel
depending on the cam choice & if you are running headrs there should be more in there

[tecmopar]

  One thing you can do is read up on some of the magazine articles of different engine build-ups that were put on a dyno to get true results. Then you could use their tested combo and be pretty close with your numbers if you don't have access to a dyno. You can't believe any of the ads that tell you this is worth 20 HP and that is worth 30 HP, there mostly BULLS**T. My daily driver (now don't hate me guys) is a 2001 BULLITT edition Mustang and every part that I installed on it was immediately dyno tested and a few parts went right back because it stated "25HP gain" and only produced 8HP and so on. I've had quite a few arguments with the manufacturers because their excuse was "must have been a hotter day or raining etc etc". But that was always factored in and they took it back, what ever it was. I know It can get a bit expensive to do it this way but its the best way I know of to be sure.
  Now when someone asks me what the #'s are I can tell them it puts down 446 HP, 438TQ at the wheels and I have dyno sheets from 2 different dyno's to prove it and 11.59 time slips on street tires. It cost a bit to do this but it was worth it. I think I'm rambling on here so back to the original question. Using someone elses TRIED and TRUE set up is probably the best way to go, if he will tell you. And again, over the past years, there have been some great articles in just about all of the Mopar magazines on engine builds that are proven combinations. If I remember correctly, Steve Wann runs a 440-6pak Roadrunner in the mid 10's in stock class which is really haulin' ass for a big car. So good luck with what ever your trying to do.