NC Jeff

Bone stock 398 rwhp 385rwtq.

After installing V max throttle body;
389rwhp 376rwtq.

Temp for second run was 95.8 vs.94.4 degrees,
Humidity was 43% vs.35%.

Both runs on Dynojet WINPEP 7 all wheel dyno.

Not exactly what I was hoping for...

tomiboy

ouch!

0Mike@NorrisMotorsports

Hi NC Jeff,

Your results sound just the opposite from what we have seen on the LS3 cars. Not a lot of info in the post, but I am guessing back to back runs on the same day, bone stock no tuning ?? Any AF change from the base runs to the CNC TB runs??

Do you recall what the coolant temps were for each run?? I have seen on a stock LS3 on a hot day have the coolant temps go from 185-195 on a base run to 205-210 or higher on a second run and pull a bunch of timing. If you have any data logging like an HP Tuner log file it would be nice to look at to see whats up.

If you could I would say that you should give Pete a call at VMax at 813-469-4665 and let him know what is up. If this data is correct, I am sure he would want that TB back for testing and send you another.

Mike Norris

NC Jeff

Mike, Thanks for your quick reply. The dyno runs were actually done two months apart.. yes the humidity is definitely higher here in July, but I would have expected maybe no gain rather than a loss. I don't recall what the water temps were, and I don't believe any tuner was hooked up.

From your experience, should there be that much of a fall off in performance due to slightly worse atmospheric conditions??

FYI both runs were bone stock (other than the throttle body on second run) with no changes to AF or tune. First run car had app.6k miles, second run app.8k.

had2have-it

I have an '01 C5, do you do those TB's and if so, is there any question as to producing similar results that you have gotten for the C6s' ? thanks

0Mike@NorrisMotorsports

I am with you that I would expect if in a worst case scenario there be no gain. The weather dose seem similar so I would not blame it, but not rule it out to a point either.

But without any ECM data here is what I would guess.

If the engine temps got pretty high, which they can setting still with a stock ECM, it would hurt for sure. I have seen 10HP or so difference from 190*F and 210*F.

One other thing could be Intake Air Temps. At 95*F IAT's you will lose 1* of timing and that can be 3-5 HP. At 104*F IAT's you lose 2* of timing and that can be 6-10 HP. At 113*F IAT you will lose 7* timing which is a bunch, but a gradual climb, so at 109*F IAT you can lose about 4-5* of timing.

When we do our testing we are pretty strict with keeping the IAT's and ECT's the same or as close as possible to get a proper A to B test.

Hopefully this helps explain, at least possibly, why there was a loss. Without before and after ECM data it is hard to say. Also, if the car was strapped differently, that can make a difference also, but it would have to be done way differently for a 10 HP & TQ difference.

I did talk to Pete to let him know about this thread and he recalled talking to you after you had it installed and that he recieved the core back before the dyno test. He mentioned also that you felt a noticeable difference in the seat of the pants power as well as better throttle response. I am wondering if that seat of the pants feel is still there.

Hope this helps.

had2have-it,

I think I talked to you earlier and answered your questions, but if not, on the LS1 and LS6 cars, we generally see maybe 2-4 HP and TQ and most likely would not feel this while driving, but the throttle response is greatly improved for sure.

Thanks.

Mike Norris

NC Jeff

Mike, again I appreciate your prompt response. Its nice to see that some of the more knowledgeable Corvette enthusiasts are keeping track of these threads!!!
I'll try to keep this as short as possible....
I absolutely still feel the same of my "seat of the pants" dyno.. The car feels crisper across the entire RPM range. After installing the Vmax piece, we took a little road trip to a legendary two lane twisty in the NC mountains known as "the Tail of the Dragon" I can remember exclaiming to my wife/co-pilot, " this thing is just SO f*&#^ing strong!!!! It would pull effortlessly out of 15-20 MPH corners in 3rd or 4th gear!!! Which just magnifies my confusion at the dyno #'s.
I agree with you that temp can play a big factor.. After looking at the printout from the speedshop, I've come to a few conclusions.. I question some of the readings they came up with. I really doubt that it was 94 degrees on May7, but I could be wrong. I also think that there is more than 8% humidity diff. Both sets of runs were done with the overhead door open. Also, the car was left running while it was strapped down both times. With the stock thermostat, the car always runs 205 -210 so i doubt that coolant temp was a factor. I also have a problem with the A/F numbers as the graph goes off the chart between 5500-5750, which they did not have an explanation for, nor seem to be concerned about... So now we have so many variables, I'm doubting the baseline numbers... Anyway, I'm not driving a dyno # I'm driving the nicest car I've ever owned, and maybe I'll pick up some additional HP down the road due to the foundation I'm laying now..... Thanks so much for giving my post the attention it probably didn't deserve..

corvet786c

Why dont you guys just port your own and save your money. I thought there was a write up on this by sanding down the rough part of the throttle body and making it smooth, one of those DIYers. Just asking. I would be upset spending the money and not gettin the results.

0Mike@NorrisMotorsports

Thanks for the info NCJeff and it all seems to make more sense that the dyno info is not an accurate depiction of actual results.

It would be nice to have all of the pertinent data, but we do not so it is a moot point for sure. Now, if you you felt there was no seat of the pants difference and then a bad dyno, I would say we need to get you another unit. But it seems the dyno number aquisition is the issue, not the VMax TB or results.

Mike Norris

66yellowstingray

so what is the current pricing now? This thread started years ago and I don't want to read every post.

0Mike@NorrisMotorsports

Current pricing is $149 plus $9.95 shipping and handling. There is also a refundable $400 core fee. Indiana orders will incur 7% sales tax.

I believe I have moved about 200 of these and there have been 7-800 total sold.

Just let me know and thanks.

Mike Norris

Quick Silver Z

Mike, would the TB swap affect GMPP warranty in any way? I know the parts look the same on the exterior but your added markings might raise Goodwrench eyebrows, no?

Thanks and great work!

0Mike@NorrisMotorsports

I do not think there would be an issue with GMPP as the markings are in a spot that you can only see with the TB off. As of yet we have not heard of anyone having any warranty issues with our TB's.

Hope this helps.

Mike Norris