Dyno numbers of 500 cui stroker OK ?

[wildtom]

Hi !

I need some input here ..

I have a 1970 superbee and my machine shop have done a new engine with following specs

sis 440RB Block
500ci Stroker Kit mit 4.15 Hub
H-Beam Rods 6.760
Ross Pistons
Compression 10.5:1
Edelbrock Aluminium Heads
Competition Cams 225-4
mechanical Lifter
Competition Cams Roller
Manton Pushrods

TF727
Converter TCI 142200 Hemistyle with 2400rpm stallspeed


I did a dyno run yesterday on a dynotech and we came out with max 387 HP on the wheels @ 4200RPM and a tourque of 560lb @ 2500RPM

I need some input here. Are the numbers ok ? I would have expected approx 500 HP on the wheels. So i am dissapointed - my engine shop sayd that the numbers are ok and that the engine itself delivers approx 500HP due to the loss of approx 25% through the driveshaft

So what di you think ?
Ok or not ?

Thanks !

 

[Kern Dog]

I don't know the cam that you have listed, but my 493 made 369 at the tires with the unported Edelbrock heads and the MP 509 cam. I was pissed with my number as well.
Old style Torqueflites must be much less efficient as compared to new transmissions. I hear of dyno tests on late model cars where the numbers to the wheels are closer to the flywheel ratings of the engines. Automatics will show a lower number compared to manual transmissions anyway. Your torque number is great though. If this is a street car, you'll probably love the setup as-is. The power will be right in the rpm range where you spend the most time. Big power from 3500-7000 is for the guys that only drag race their cars, not street cars where we often idle at stoplights, run at 65 on the freeway, etc.

 

[wildtom]

Hmm .. Thanks !
How much does the carb matter ?
I have a six pack on it ..

Really need some suggestions here ..

Thanks !

 

[wildtom]

Yeah its a street car - i dont race ...
If it is what it is - ok

I just need to know if the numbers are ok and make sense ...

Would be the numbers better with a manual shifter?

Thanks

 

[benno440]

seems a little low to me, I recently got my 505 done, it has stealth heads, less compression and hydraulic lifters and made 400 at the rear wheels, which seems very low as well

 

[terzmo]

seems low....

 

[eric383]

I thought I remember hearing awhile back that different brands of chassis dynos gave varied results. Maybe someone more knowledgeable can comment. How does the car drive? Is it responsive and are you happy with it? At the end of the day these are just numbers and how it drives is really all that matters. Cheers.

 

[Hemirunner]

Given the combo, it's probably pretty close. RPM heads and relatively small cams in a 500" engine aren't going to make big HP.

 

[HYRDGOON]

This is the exact reason my buddy said he hated running cars on the chassis dyno at work for customers. Great tool for tuning but he said 9 times out of 10 nobody was happy with their results because everyone thinks their number should be higher to the wheels. He said 25-30% loss is to be expected to the tires... My 522 made 530hp so at a 30% loss to the tires it would be 371hp.

I'd be happy with that

 

[demonram]

The 451 in the satellite puts 370 HP and 460 ft lbs to the tires. 484 cam, stealth heads, performer RPM, 750 edelbrock, 10.5 comp, 17/8 headers w/21/2exhaust, 2800 stall, with 355 rear and 275/60's. I'm super pleased with the power and drivability. I am thinking of going to a 3" exhaust, almost too much torque ( yeah right ). I can't keep it from spinning if I give it any quick pedal. I'm thinking it might balance the numbers. Take care

 

[lewtot184]

some people use percentages to figure loss, some use a fixed number. a torqueflite by itself will eat about 45hp. generally you will lose 20-22% for a near stock converter auto and about 15% for a stick. some say a flat 90hp for an auto,...? loose converters loose more and aren't very efficient with high torque engines.

i think these 500 cube strokers that most guys put together for street cars are somewhat dismal and don't seem to have longevity for a street engine. 500hp from a stock displacement 440 shouldn't be a challenge considering today's parts. i have a friend who did a 508 rb engine, did his homework on it, blew some $$$, and made 465hp at the wheels with cast iron exhaust and torqueflite; think it was around 570hp at the crank. the car ran some 11:60's at 121mph with a 3.23 gear in 4150lb 67 charger. unfortunately the engine didn't last; no fault of the builder, in my opinion just taking things to the edge.

before the current engine in my 65 coronet i had an iron headed (good heads) 6-pak engine. i think it was 475-500hp, 500+lbsft of torque at the crank (,020" over 440, 9.3:1 comp, small solid). the car was so violent in 1st gear it just wasn't fun to hammer. i just don't see the need in the strokers for something to drive.

 

[IQ52]

We've run in chassis dyno contests all across the nation. I don't think you realize how much 387 HP to the rear wheels really is. When you start to get into the 500 HP to the rear wheels with a normally aspirated engine you will be making more horsepower than most power adder cars. In the normally aspirated class, when at the DynoMax Power To The Wheels Dyno Contests in 2008 and we were making 511-528 RWHP, we were in the top 10 in the nation, not the top 10%, the top 10. In the past seven years things may have changed somewhat, but not that much.

 

[mentor70]

welcome to the world of NET horsepower...you didnt list the carb and intake you have on the engine, i think that there may may be some power left on the table, but not much.

 

[inri]

A couple of questions:

What intake do you have, a dual plane or single?
Are the heads ported/polished or out of the box? Are they port matched to the intake?
Were you able to tune the car on the dyno? A mismatched carb that is too big or small can eat hp.
I really think IF you want more HP it's easily within reach.

I've read online that rule of thumb is 18% for drivetrain loss. So your just under 500hp at the flywheel, maybe 480-490 ish.
Getting 550+ hp from a 440 is relatively easy now a days. Your heads may be the limiting factor...

This could make all the difference.

 

[coloradodave]

"before the current engine in my 65 coronet i had an iron headed (good heads) 6-pak engine. i think it was 475-500hp, 500+lbsft of torque at the crank (,020" over 440, 9.3:1 comp, small solid). the car was so violent in 1st gear it just wasn't fun to hammer. i just don't see the need in the strokers for something to drive."

Plain and simple, Lew: bragging rights. On the street drivability and the ability to hook up are what makes a car fun to drive. Those huge horsepower and torque numbers are for the guys that like to impress by cruising around the car shows, not the guys that like to actually DRIVE their cars. Not knocking it; to each his own...

 

[lewtot184]

"before the current engine in my 65 coronet i had an iron headed (good heads) 6-pak engine. i think it was 475-500hp, 500+lbsft of torque at the crank (,020" over 440, 9.3:1 comp, small solid). the car was so violent in 1st gear it just wasn't fun to hammer. i just don't see the need in the strokers for something to drive."

Plain and simple, Lew: bragging rights. On the street drivability and the ability to hook up are what makes a car fun to drive. Those huge horsepower and torque numbers are for the guys that like to impress by cruising around the car shows, not the guys that like to actually DRIVE their cars. Not knocking it; to each his own...

i tend to agree with you. is it a "numbers" game, maybe the fad,.....? anyhow, tomorrow i go search for a machine shop to start building my next engine; stock stroke pump gas 440.

 

[Hemirunner]

Until you've driven a car with a dead flat 600+ ft/lbs torque curve on the street, you just won't understand what it's all about. It's like crack....

 

[HYRDGOON]

I put a lot of miles on my big stroker and I know I'm not the only one. I think the call for the big strokers isn't as much "ego" but ppl wanting to get as much out of a build as they can and the availability of Stroker Kits now.

I agree with Hemirunner I had a mildly warmed up 383 before the crate that's in there now and I could never take a step back.... Guess that's why I'm procharging this big Stroker

 

[theman440]

Seems low - my .030 over 440 put 485 to the wheels.

 

[SlinktRR]

The peak horsepower seems low at 4200rpm. Every bb mopar dyno curve I have seen builds to 5000 at least before falling off.