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Getting ready to finally put the C6 Z06 on the chassis dyno (Dynojet) in February.
My car has a new 3.90 rear gear ratio (factory is 3.42), so it's going to skew the chassis dyno numbers down a bit.
With that said, let's see what people guess the final chassis dyno number is going to be
Engine is a LS7 based 468 ci engine, built by Horsepower Research.
The engine is going to be run with a version of the FAST LSXHR plastic tunnel ram, Performance Design's pTR carbon plastic tunnel ram, and a NW112 throttle body.
My engine dyno test was done with a pre-production FAST LSXHR, with a FAST 102 throttle body and Ignite 114 fuel ......... 761/635 was the initial numbers (4th pull).
It looks like the engine picked up an additional 5 HP and 6 ft/lbs on the last runs (24 pulls in total) when I was testing other intakes, but I don't have an official number with the FAST other than the 4th pull listed above as we didn't have time to re-run the FAST.
I also ran a billet top load Holley Hi-Ram with an Accufab 6500 throttle body, which made 780/645 , but I'm not using that particular intake
Car will be run on both E54 (best we have in AZ) and MS109 on the chassis dyno, instead of the Ignite 114 fuel used in the engine dyno test.
Take a guess at what the chassis dyno numbers will be........
Wow thats the info I needed! was that with same tb on both intakes? Looks like the fast bests the holley by 9 hp?
Yes, same throttle body, injectors, and fuel.......just replaced the manifold.
For my setup, the Holley Hi-Ram was very sensitive to the type of lid and throttle body size that was attached to it.
For instance, I ran a replacement carbon fiber lid on the Holley base and lost a few horsepower,
I then ran a custom billet lid and Accufab 6500 throttle body on the same exact base...no other changes, and picked up almost 20 crank horsepower......
Thank you for all the info/data! It is seriously appreciated. Was the fast ran with with the standard long runners they come with? Looks like I should be ordering the fast vs holley!
Thank you for all the info/data! It is seriously appreciated. Was the fast ran with with the standard long runners they come with? Looks like I should be ordering the fast vs holley!
I ran all three trumpet sizes on the FAST....the dyno run I posted was with the long runners which ship with the intake by default.
AS odd as it sounds, the mid and short runner trumpets made no difference on the engine dyno....peak power came in at the same RPM. We think this was mainly due to the 102 throttle body not supplying enough air at the upper RPM's....we saw significant kPA drops as we approached 6500 or so. Once I complete my initial chassis dyno sessions with the long runners and NW112 throttle body, I'm going to re-run the mid and short runner test again, albeit on a chassis dyno, to see what happens.
We were surprised that it didn't affect the power band delivery, even with the throttle body limitations.
As an added bit of info, the ported MSD ran neck and neck with the pre-production FAST with long runners........
I will be following along to see what your results/gains are! I was going to run my current 102 tb, but if there are significant gains I would change the tb size and the runners.
Will your chassis dyno be o the 102 or 112 throttle? Also confirming manual trans, 9 inch axle?
The NW112......... TR6060 manual transmission (ZR1 spec gearing), and my original, fully built OEM Z06 rear diff with the new Motive 3.90 ring gear set.
The 3.90's are going to bias the RWHP readings down a few HP...... I'm guessing somewhere between 10-15 RWHP.
It will be only the 112......I already saw what the 102 did, and you can see the potential difference by looking at the Accufab 6500 throttle body dyno test above.
I get questioned about the chassis dyno number drop with gears too, and while I haven't seen PatG post in a while, he had a great explanation of the phenomenon with respect to drum roller style dyno that is much easier to understand than me trying to explain it
"Higher ratio gears will give you lower chassis dyno numbers for a strange, but logical reason. In essence, the DynoJet calculates hp based on the time it takes to spin up the 2800lb roller assembly. It's basically work divided by time and rpm. Think about this: If you car is at idle in neutral and you stab the throttle, it will take time to accelerate to redline...let's say 1.1 seconds. Now let's say it takes 8.2 seconds for your car to accelerate the DynoJet from low speed to top speed with 3.23 gears and 7.3 seconds with 3.73 gears. Dyno printout says 355 rwhp with 3.23 gears and 346 rwhp with 3.73 gears...why?
Think aabout this: In the 8.2 seconds it takes to spin the rollers with 3.23 gears, it would still take the motor about 1.1 seconds to overcome its own inertia (idle to redline). There's about 13.4% of the work used just to accelerate the motor itself. With 3.73 gears, the time to reach redline decreases to 7.3 seconds. Divide the 1.1 seconds into the 7.3 seconds and you will see that overcoming the internal engine inertia costs 15.1% of the work with 3.73 gears. There is less hp available during this time period to spin the rollers so the DynoJet will read a slightly lower hp figure. Make sense, or did I lose you?"
im interested to see how this goes.
my car was dynoed in california somewhere on 91 and put down 638hp with the 3.42s. Unfortunately i never got a dyno sheet, just that peak number.
i swapped to 3.90s a week or two ago and its such a great change.
First want to say the motor seems very well built to sustain pull after pull like that. And I presume for one second to speak for the site when I say thanks for all the data.
My guess with the 102, I think you will be in 685-690 territory rwhp. No reason it would not clear 700 other than just playing the dyno and guessing at drivetrain efficiency.
With the 112, I cannot imagine it not clearing 700 with some room to spare.
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HPR 468.....engine dyno versus chassis dyno 
