Dyno Day RESULTS!

[Zoom This]

Ok guys, it's time to show your hands. A great day of "run what ya brung" at Scott Performance speed shop in Santa Clara. Eight of us strapped our rides to the dyno rollers while dyno operator and owner Ted put each of the cars through the paces. Congratulations to Chris for guessing closest to his actual RWHP and taking home the entire pot!

Bill - 418W stroker - estimated RWHP 448 - Actual RWHP 478
Rich - 468 Shelby Alum stroker - estimated RWHP 447 - Actual RWHP - DNF due to lean conditions during pull.
Chris - 428 - estimated RWHP 382 - Actual RWHP 372. HP pool winner!
Randy - 460 - estimated RWHP 400 - Actual RWHP 385
Tom H - 350 Chevy - estimated RWHP 280 - Actual RWHP 267
Tom B - 427W, Rousch - estimated RWHP 427 - Actual RWHP 468
Greg - 427W - estimated RWHP 415 - Actual RWHP 427. Hey Greg, you should get some kind of prize for the magic number!
Nathan - 392W stroker - estimated RWHP 365 - Actual RWHP 390


Hey, we gotta do this more often!

[Randy Rosenberg]

Had a great time. Thanks for coordinating this event, Greg, and thanks again for breakfast.

I must say that I'm a wee bit disappointed with my 385 RWHP, but at least my carb was in tune (not too rich or too lean, no pinging, etc...). I should have done a pull with my air-cleaner removed, as I'm sure it's choking my engine.

Again, had a great time, and I'm looking forward to doing it again.

Thanks,
Randy R...

[nblumberg]

Thanks guys - really a pleasure meeting all of you. Very informative day, and I thought the shop was good. I'm really impressed by those roush 427w motors.

Final numbers for me from my stock 392W Ford Crate was 390.1rwhp@5500 and 377.7lbs. It appears the crate has a somewhat conservative advertising by ~20hp. Should have thought about that before handing over my ten bucks!

-Nathan

[Tom Howland]

Thanks Greg for the breakfast and dyno. Had a great time. Here is a picture at breakfast at Country Inn.


Here at the dyno shop.

[cobrasnake]

Greg - Thanks to you and Ted for arranging a GREAT day! I saw nothing but smiles on the faces of all the guys. It was also nice to see some new faces (ie. Daryl and Nathan) - welcome aboard. Thank you again for breakfast - you really know how to throw a party.

Zoom - thanks also for giving pointers and helping us all out - that new motor is schweeeeeet. It is people like you that make this such a great group of guys to be associated with.

Tom B.

[Greg tripp]

Thanks to everyone!! I had a great time and the fellowship is what it's all about, after all, it's the people that make the cars so much fun!!!

Thanks again and hope to see ya all soon!!
Greg

[badrich]

Thanks very much for a great breakfast and setting this up with Ted, Greg. And the donuts, Tom. I think. We all had a great time, and while I was disappointed that my engine's lean conditions necessitated a shutdown at 5K RPM, I learned what is necessary to get ready for another visit to Tony's for some final tuning. I also learned why they call them things "turkey pans." After I remove it, along with the Holley 850, I'll do some jet changes and get the engine running optimally before reinstalling it. Some of this "original" crap, while looking cool, can be a pain in the ass. And thank you, weather god, for giving us a beautiful day [at last]! Rich

[dlang14]

I had a great time. I just wish I had made it to breakfast so I could have chatted with more of you. Hard to talk during pulls

I'm really looking forward to attending more bay area events once I get my car done (still looks like April).

I'll have to get my car in there for a dyno pull after its got a few miles on it. I'm more impatient than ever!!!!!


Daryl

[greg schroeder]

very cool info! Thanks!

Any idea about were the alum. stroked bb would have come out?

curious...? what kind of dyno?, elevation, weather? Corrected HP?

[Randy Rosenberg]

1. Dastek Chassis Dyno
2. Elevation - I'd guess that it's under 100ft.
3. Weather - beautiful. Sunny, clear, dry. It was probably in the high 50's when we started in the morning, and probably in the high 60's (maybe 70 even) by the time ended.

[nblumberg]

It was in santa clara, CA elevation is pretty much 0 (150ft), and temp outside was ~55 for the earlier runs, and maybe 65 by the end. it was a load bearing chassis dyno, but no idea as to the specific model.

ack... randy beat me.

[Zoom This]

Rich's stroker aluminum big block had big expectations. Rich can probably provide more information on it. I think he mentioned that it has an engine dyno sheet from Shelby at around 550 hp at the flywheel. Tell us more Rich!

[BossCER]

It sounds as though you all had a great day!
I'm curious to know if any of you had dyno'd you engines on an engine dyno prior to making your pulls on the chassis dyno? If so, how big a difference in the numbers. I'm wondering how much I will lose in the drive train.
Thanks for the cool info.
Chris

[badrich]

I'm still trying to figure out how the dyno sheet from Shelby looked so good and why I ran out of gas at about 5K RPM on the chassis dyno. It was suggested that I go up two jet sizes and then retest, which I can do, but I am also wondering if I may have another problem. I am using the original Shelby high capacity mechanical fuel pump, which they said should be sufficient for my needs. I am also going to check out the size of my fuel lines to make sure they are large enough. I have wound the engine up to close to 6K RPM while autocrossing with no problems, although it did stumble when I floored it in second gear at about 2-3K RPM (I was looking at the course, not the rev counter), but a quick down shift took care of that, so even with a ton of torque it doesn't like low RPMs. Anything I have overlooked?

Anyway, here are some numbers from the Shelby Dyno sheet:

3500 RPM: 352.8 HP 529.5 Torque 12.74 A/F 422 CFM
4000 RPM: 392.6 HP 515.5 Torque 13.07 A/F 440 CFM
4500 RPM: 456.1 HP 532.3 Torque 14.68 A/F 505 CFM
5000 RPM: 509.7 HP 535.4 Torque 15.67 A/F 570 CFM
5500 RPM: 546.3 HP 521.7 Torque 16.83 A/F 644 CFM
6000 RPM: 558.8 HP 489.1 Torque 17.60 A/F 702 CFM

Looks like the S&H air cleaner will have to go into the car show only box, along with my nifty black and yellow '65 Dealer CA license plate.
Any suggestions? Rich

[Greg tripp]

Hey chris,
I have a 427w and on the stand it was 525hp at the flywheel and on the chassis dyno it was 427rwhp at 6000rpm. Should of used a 6500 chip instead as the numbers were on the rise when the rev limiter kicked in. Builder said power would curve at around 64-6500. he said could use a 6500 to 6700 chip no problem.

Greg

[BossCER]

So Greg...that's a loss of about 19% from the flywheel to the tires. Is that about what one could expect to lose on average?? Thanks for the info Greg.

Chris

[Zoom This]

Rich.... you are way lean past 4000 rpm. The A/F should stay around a good median of 12.5:1 to make safe power. I have no idea how Shelby made that kind of power numbers if the A/F ratio is true and accurate. HP looks very good and what I would expect, depending on cam specs, CR etc.

[Zoom This]

Chris. I didn't have my motor on an engine dyno, just Dyno Sim software prediction. Both Hot Rod mag and Popular Hotrodding and Horsepower TV did comparos between the Dyno Sim software and actual engine dyno results on the same motor. +- 1-2% was the error factor. My engine builder used this to predict 560 hp at 6k and 564 torque at 4500 rpm. Yah, 20% is about right. 15% for drivetrain losses and 5% for the sidepipes. Total of 20% parasitic loss.

[greg schroeder]

Originally Posted by badrich

I'm still trying to figure out how the dyno sheet from Shelby looked so good and why I ran out of gas at about 5K RPM on the chassis dyno. It was suggested that I go up two jet sizes and then retest, which I can do, but I am also wondering if I may have another problem. I am using the original Shelby high capacity mechanical fuel pump, which they said should be sufficient for my needs. I am also going to check out the size of my fuel lines to make sure they are large enough. I have wound the engine up to close to 6K RPM while autocrossing with no problems, although it did stumble when I floored it in second gear at about 2-3K RPM (I was looking at the course, not the rev counter), but a quick down shift took care of that, so even with a ton of torque it doesn't like low RPMs. Anything I have overlooked?

Anyway, here are some numbers from the Shelby Dyno sheet:

3500 RPM: 352.8 HP 529.5 Torque 12.74 A/F 422 CFM
4000 RPM: 392.6 HP 515.5 Torque 13.07 A/F 440 CFM
4500 RPM: 456.1 HP 532.3 Torque 14.68 A/F 505 CFM
5000 RPM: 509.7 HP 535.4 Torque 15.67 A/F 570 CFM
5500 RPM: 546.3 HP 521.7 Torque 16.83 A/F 644 CFM
6000 RPM: 558.8 HP 489.1 Torque 17.60 A/F 702 CFM

Looks like the S&H air cleaner will have to go into the car show only box, along with my nifty black and yellow '65 Dealer CA license plate.
Any suggestions? Rich

This is really a great thread guys. I love this kind of stuff.

I'm real curious were the power comes out for one of these engines once in the car. Could you share the info of air fuel and HP before the pull was shut down just to give us folks an idea of numbers?

I'm not familiar the type of dyno which was used, but is the dyno load adjustable to the estimated weight of the vehicle?

[CJ428CJ]

I put together a little table to compare the results I got off of the chassis dyno vs what DynoSim predicted for my 428. Roughly an 18% loss on average. Columns left to right are RPM, chassis dyno RWHP, DynoSim RWHP, % loss, chassis dyno torque, DynoSim torque, % loss.


2000 108 179 40% 283 470 40%
2500 172 223 23% 362 469 23%
3000 230 268 14% 402 469 14%
3500 276 333 17% 414 500 17%
4000 318 386 18% 418 507 18%
4500 350 427 18% 408 498 18%
5000 368 454 19% 385 477 19%
5500 372 461 19% 356 440 19%