FYREANT

Some of you have been following my build and my quest to be able to beat a stock Z06 with my S-trim supercharged C7. Saturday night, that was ALMOST a reality. Previously I raced this same car and it pulled on me up top by a good margin. I swapped pulley, added more meth, and we retuned. I also mounted some Nitto NT05R's for traction. Saturday night's race was SOO close. We raced twice, both from a 45 roll. The first time he got the jump by a split second and held me off all the way until we let up. The second race we got a perfect even start and we were DEAD even all the way up to 125 when I let off. My new drag radials have a lot of sway which scared me so I let off. (my first set of drag's). Also, my car is apparently not running right which I have another thread about. I was told it's breaking up bad, possibly due to too much meth or a plug issue. So I wasn't running my best, and I was dead even with him. Man I am soo close to my goal! hahaha

SquatchMachining

Im surpised you are having a tough time keeping up with a stock Z06. A blower/meth/header C7 will make north of 700whp easily. It shouldn't even be a close race. Guess im a little bit confused by that. Especially with drag radials. Im not familiar with your exact setup but I would think you would walk a stock Z.

FYREANT

I assumed as much as well. Not sure why. Once I get my issue resolved with it running a bit off I will re-race him.

My setup is:
A&A V3 Si @ 10PSI (3.47" pulley)
Alky Control dual meth
ARH Long tube catless headers
NPP exhaust
Weapon X ported TB.
170* Tstat
LMR Breather tank

was custom dyno tuned by FSP in Bradenton. Pulled 639HP and 618TQ on a mustang dyno. Most of the cars that are pulling 700+ are doing that with the ECS 1500 kit. The V3 S trim I am running is a bit smaller of a blower.

leadville1

Maybe the Supercharger profiles make a difference too, on a dig a roots based charger is going to have more available torque and the Centri will out pull it up top.

I noticed on my car that at 6800 rpm it seemed to be breaking up too, wondering if the plugs are shot at 13k miles.

SquatchMachining

They raced from a 45 roll though, the screw blower has zero advantage at that point. And even from a dig, unless that Z has GOOD drag radials on it, its just gonna blow the tires off.


I would step up to a Ti blower and wake that thing up. Or jump straight to a YSI if you have plans to build a forged engine.

blue_bomber697

I pull on stock Hellcats with just ECS and Headers. And Hellcats and Z06's are quite comparable on a roll. Im running 586/572. You should be very easily pulling on a stock Z06... Something is definitely wrong.

SquatchMachining

That was my thoughts as well. Making the power he is, it should be a easy win...

C7BB

Yeah brother.., it's not running right. My car EATS Z06's! I've raced a couple. One even had headers, CAI and was tuned. Wasn't even close to 135mph or so...

FYREANT

I've only had the SC on there for about 6K miles so far though. Hope im not fouling plugs already. They were a brand new set of NGK 6510's.

Thought about swapping to a Ti trim. Have to hold for a while though. Have already spent a lot of money this year on the car. No plans to forge the bottom end at this point.

I haven't raced a hell cat yet. And the Z that I raced is supposedly stock. Only way to know for sure would be for me to race another one.

Kakashi

I hate to be the bearer of bad news.... but there is something wrong with your setup.

A&A V3 Si @ ~9psi + TSP Headers + Single Nozzle Meth

I have a similar setup and it walks stock C7Z06's (and even lightly modded ones). Stock C7Z06's at my track run 11.3-12.0 123-126MPH in the 1/4 and stock C7's run 11.8-12.3 @ 116-119mph (don't blame the car, blame the drivers and climate ). For comparison's sake mine ran a 10.56 @ 131MPH with only 560rwhp on a mustang dyno (620rwhp on a dynojet) and did only ~370rwhp (mustang dyno) when stock

Before you keep modding on... try to resolve the problem or you will keep dragging it and under-performing no matter how many mods you add.

Do not think for one second that just because it made a # in the dyno, the car is "set". Real world conditions affect the car differently. I bet it is working perfectly in low / mid RPM giving you the impression of a fast car, but falling flat at high RPM's due to pulling of timing / knock (false or real) / rich / lean AFR when the meth kicks in, etc.

Kakashi

First thing I would do, is take your car to the 1/4 mile and see what it does. The MPH will tell it's own story on how it is really running.

Steven Popham

I am still saying your flooding it with meth, your rings are not going to last for **** in that car, I would bet your flowing double to 2.5x the level of meth you need. I would say your plugs are shot, change them and then turn one nozzle off and go to 5-6 on the single nozzle setting

FYREANT

That is some pretty sound advice. For comparison my car ran 12.2 in the 1/4 mile on two different occasions when it was stock. Track prep was crap, but still gives a baseline. I have not had it back to the track yet. Was planning to go next Sunday for Runday Sunday test and tune if I can get the bugs worked out. I don't think it's pulling timing though, we actually put more timing into it on my last tune because it was taking the timing well. We tuned on a very hot day. Inside the shop was probably like 100*. Timing gets up to 16* in some areas of the power band. I can post the dyno if it helps. As for AFR, when we did the latest tune session, after I added the second meth nozzle, we cranked the meth up to 8 on the gain and it was pig rich so we turned it back down to 6, where it was to begin with and it was running fine. I txt'ed my tuner already so hopefully we will see what he thinks may be the issue. I do not have a wideband in the car, but after this last weekend I think it would be a good idea to get one.

Kakashi

Another thing, I just noticed you are using a 3.47 pulley. Doesn't this put the V3 Si over it's efficiency range? I know with that my drop from 3.8 to 3.6 pulley did increase the PSI from 7 to 9, but did almost nothing for an increase in RWHP as it was a blowing volcano of hot air. Check your IAT's! I bet they are over 140 and increasing as time goes on (this will drop your power big time via pulling of timing).

(Crank Pulley Size / Blower Pulley Size) * Step Up Ratio * Max RPM = Blower Speed
(7.65 / 3.47) * 3.6 * 6600 = 52,527 RPM

robert miller

I put money you are putting down to much meth on the car man. With it cutting out on the top end I had the same thing in the c5 set up with two 15 shooting full at WOT. I had to cut it down to a setting of 7 at WOT. If it is the plugs it will get so bad that it will not even start on start up with that meth on them so bad plus will start cutting out the more you get into it on top. Are that is what my c5 did..

FYREANT

I spoke to Josh at A&A about pulley size and they advised the 3.47 is the lowest I can go and still be within efficiency range on the V3 Si. That puts me at max impeller speed. I think Andy actually posted the speeds for the different pulley's in another thread. I'll try and find it..


EDIT: Here is the post where the sizes and speeds are being referenced:

https://www.corvetteforum.com/forums...post1590908976

Kakashi

Not arguing on it being the lowest pulley you can go, but at that speed you will be blowing out a lot of hot air. Just giving you ideas on things to check (in this case, your IAT's)

robert miller

If you think those 19 in the rear are back on the street I had 15,s in the rear & up at 125 some times I was going to shi* in my pants on the road at 140 plus & run into a dimp r dimps in the road.Azz end starts going from side to side like crazy. I know the feeling on that one.

Josh@AandASuperchargers

My advice:
-Pull a couple easy to reach plugs and see how they look. Change them all if fouled out.
-Hook up WBO2 and go data log some street pulls. Run it like you did against the Z.
-Crunch the data from the street and find out if afr is off, if timing pull is too aggressive based on IAT's, if actual throttle is closing even tho pedal is WOT, etc.

Josh

CDH76

I agree you should be pulling on him as well and I'm betting you have a plug problem. If so your car is probably pulling timing. However if your car is pulling timing there is no way you would not feel that power loss.

Everyone needs to remember that not everyone is running the same setup, octane, etc.

Did your tuner turn off the knock sensors or adjustment and keep them on?