Cerra Kit update:

Cerra Racing T76 GTS Single Turbo Kit
A&A FMIC Kit
Stage II Heads
9.25:1 Compression
Stage II Heads
MTI B1 Cam
94 Octane and Torco

Just the facts:
14psi
648rwhp/638rwtq
12 psi
602rwhp/556rwtq


I just wanted to see what the kit could do before I started to lean on it (i.e. race gas and more timing). Its was 85degrees outside (probably a little hotter in the shop). Cool thing was I got no knock retard and 11.5:1 a/f up top. Hopefully if the weather holds(T-Storms forecast), I'll run it at the track tomorrow. It will only be on street tires until I can strengthen the driveline.

 

Not bad at all but I think you still have a back pressure issue. With 14lbs of boost and 98-100 octane you should be over 700rwhp.

 

I cant say yes or no on the bp issue. I do think the T76 is perfect for a stock cube motor. One thing to remember is that boost is relative. There are a couple of things that lead me to believe that I don't yet have a bp issue:
- at 14 psi, I would have expected some knock, due to elevated IATs even with a lowered CR. (I'm getting 0 kr). This is my biggest surprise. I wouldn't expect to be able to run 14 psi with no knock on pump gas.
- MY IATs only increase by 25-30 psi (on the dyno). This is true at 10 psi, 12 psi, and 14psi. Looking at the compressor map, I am not out of the window.


Relative to HP vs. Boost
Right now my timing is fairly conservative. I ran out of time (on the dyno), so I didn't have time to start tweaking the timing. Re: octane, I wouldn't agree that I am 100 octane, probably more like 96 or 97 or so. My A/F curve was pretty nice. My car makes peak hp at about 5800rpm and stays flat until I let off. I think this is a function of the cam. I have a turbo cam waiting to go in when the AFR 225's are ready. I think these two changes will improve efficiency.

 

Earl, Nice numbers!!!

 

Very nice numbers. Which shop are you dynoing at?

Mark

 

Actually, Based on the HP and Torque curves it is NOT exhibiting the tell tales of backpressure. In addition, based on the conditions and relatively stock configuations and current tune its very impressive.

Dont take the following comments the wrong way or personal (unless your guilty), but I'm sick and tired of "internet HP" dyno graphs and bench racing. Their were no short belts,no removed belts, electric WP's, no cold pulls, no ice on plumbing, no BS..
ITs HOT, MUGGY and was even driven almost an hour (well I think he drove from home) in the heat (upper 80s with 70% humidity right now), tossed on and flogged..

I see this car getting tossed almost immediatly at the track, even with a novice driver and BS tires.

Phil

 

Well it could be humity related but wouldn't the correction factor fix that on a dyno graph. 80* is not the hot out....even if his IATs are 115-120 that would still be descent IATs. I am not trying to take a way his results I think he has done great. But doesn't the Cerra kit utilize a log and crossover tube????? If so there is a potential issue right there as it is not a true header design.

Just for reference OpticZ06 made over 730/630 rwhp/rwtq with a D1 and 14lbs of boost...and then backed it up with the track times. LPE's TT 427 on my friends car only makes 11lbs of boost and makes 750/700 at the rears. Lets look at Rob Raymers Fbody Single on race gas, water/alky, and a Single Turbo making over 750 rhp rtq at 12lb of boost. That is the only reason I mentioned that there could be a restriction. You can only blow so much air through a straw...make the straw bigger and the air moves through it better...move more air in and out of the motor make more power...just some logic I like...doesn't mean I am right but seems to follow the principal of making power on a combustion engine.

I would expect about 15-18* of timing from your CR, Octane, Boost, and IATs.

 

Phil,

Are you saying that Earls 700 hp daily driver doesn't have the required safety equipment to run in the 11's? .

Cheers,

Mark

 

Kevin,
Each setup is different (regarding boost). Rob really pushed the envelope but he didn't do it on pump gas and he ran an open exhaust (exhaust cutouts). He did go pretty far using alchohol injection. I do have a propane injection setup hooked up, but I have yet to tune with it. My 12psi pump gas only numbers are pretty close to his when using pump gas and thru a full exhaust.

Re: 427tt, well thats not even a close comparison..I'm doing stock cubes with moderately worked heads.

Re: Optic, well his car is just a FREAK! That guy has the keys to the city and he aint sharing. He must have some amazing heads and a well spec'd cam.

I went to the dyno today not to try to hit a huge number, but to do some testing. I recently decided to take my car in a different direction and I wanted to see if the kit could handle it. I've spent a year tweakin the kit and I believe that I have it "perfected". My coolant temps range from 180 (cruise) - 200, depending on the outside temps and if I am hammering on the car.

My whole purpose for posting this was to share info. A lot of guys have been emailing me asking about my setup. Cerra is no longer in business to offer this package as a kit, but it is representative of what can be done, with a good header, crossover, down pipe (3") and Andy's fmic kit. Twins are nice and are sometimes easier to package (this is debateable). A single, although its not without its own problems, is a viable option. Btw, its not a log style setup like Raymer's. If there is enough interest, I do know where I could possibly get a header or two made up (not a plug, just may be able to help a few fellow C5 owners).

 

Kevin,

Lets make it easy..

Raymers car had a fuel system that would not support 500hp on race fuel on a good day..you figure out where the rest came from.

427 cui@750rwhp is less per cubic inch than Earl made..

Earls car setup I feel will make 700rwhp on 14psi when its done..very impressive.Jee wizz 700rwhp out of a log.hehe Thats been happening for years.
He made his power on a heat soaked engine with inlet temps over 135 degrees on back to back pulls. The tune is a total cream puff with a very safe AF of 11.5 or lower and not a hole lot of timing.

You have to hand it to him, it's pretty stout.

Oh, and besides being heat soaked, the SAE correction factor does not handle boosted cars well at temperature..we have known this for a long time. They get hosed in the summer and a bonus in the winter.

And, just fror the sake of arguement..I had pretty much nothing to do with this car..Just making some point and sending some cudo's

Phil

 

Ya..right before I get the boot..They have really been leaning on us this year, even on our Milan track rental a few weeks back.
Hopefully Norwalk give us a break at the end of the month.
If I can get some spare time Im going to easy cage it for the Corvette forum Milan even in the fall. But, I dont think I have enough for Earl and another member with a 422 on spray.

Phil

 

Anyone who races on street tires at that power level is asking to smash their car up.

 

Haha..Cant argue with that one..The track I think he wants to go to would be the one to do it..Major IHRA events there and its big,wide and flat..But it should be fun to watch.

Phil

 

Well lets hope not...

 

Phil,
If you look back on my first post I did hand it to him. But we have had this conversation before in an earlier post regarding the Compressor Map...and I also think he could get 700rwhp out of the thing and I am just curious as to whether or not there is a restriction. Not measuring manifold backpressure during R&D, that is if one is looking or not..maybe they are satisfied and not worried about it. But if I was looking as to why it wasn't squeezing out as much as it is mapped for, I would start looking at exhaust restrictions..be it manifold design, down pipe, cam etc....and I would start by taking some manifold bp test just to get an idea what it was..so I would not be chasing suspected problems that are not really the problem. In any case good job Earl.

 

Kevin,
You made a blanket statement "I think you still have a back pressure issue. With 14lbs of boost and 98-100 octane you should be over 700rwhp."

And my response is basically look at the factual data supplied. Peak Torque level and at what RPM it occurred and Peak HP and RPM. Experience would tell you that it infact does NOT show the tell tale signs of an issue with back presure. There is to much arm chair quaterbacking and apples to orange comparisions on the internet that only lead to dissapointed people. My mission is to help provide information as to if there really something to be dissapointed about .

 

Good numbers Can't wait to see the time slip.