Is this an auto car? and are you locking it up?

 

Car is a 6 speed.

Things just got worse. Dyno was uncorrected. Corrected it reads:

379 rwhp
370 rwtq

I will speak to race-prep and work out the situation, I'm sure it will be resolved.

JIm

 

Ouch...

you guys must check that...

Sorry for saying, but its not the first time someone has been dissapointed at race prep...

Ask chuck97ss

I am a bit worried now...

330cfm must yield over 450++++++ rwhp...

from calcs.. taht is what a 260cfm head would yield in power.

 

What cam and what TB?

 

my cousin's 96 TA M6 made 444 rwhp corrected (457 uncorrected) a couple of weeks ago with a stock-rod 383, ported stock heads, and the XE 236/242 cam.

it made 414 uncorrected on the first pull and made 457 on the 5th pull. putting together the right heads/cam combo, and tuning are the 2 most important things if you wanna make big power.

if i had a set of high dollar AFR heads and my badass stroker engine made ~390~ rwhp, i'd go postal on somebody...

 

As taken from his signature

New Motor DONE
Fully forged 383
AFR 220's, flows ~330 cfm
Cam Specs 230/245 @ 050” lift is .622/.640 w/1.6 and a 114 lsa

 

Who picked the cam for you?

 

yeah...i'd love to hear somebody explain why that huge split in duration is needed with those heads.

 

I dont think its the real reason you are off 50-80rwhp...

You will just have to spin the engine quite a bit...

I was wondering though what rpm range you had that power...

It looks like a blower cam.. has 2º overlap...

 

Uhhh, my math puts that cam at 10deg of overlap at .050 and on a 383 that cam is not out of line, if it's a SR it's a pretty mild street cam and if it's not advanced too much it should peak in the mid 6000 range. Then again as a street cam it's not a bad choice if it's a driver.

As for the split, that much split makes more sense to me than 3 degs of split which I have seen. We have 23 deg heads here, that amount of split might be WAY off on his heads since those intakes are probably not that strong.

My guess is if he even has 330cfm the .400 number is pretty weak for those heads and the average flow of them is not very good. Just a guess from a 370rwhp number. I'm not going to get into the pissing match of IF they flow 330cfm or not.

If that's the case that the heads are not making good average flow then the the cam's split was made for a good flowing intake and a standard 23deg exhaust then it's not going to be even close when the intake is down from what the cam designer was told.

BTW not my cam design in that puppy.

A huge split is not a bad thing on cams guys, sometimes it's what the motor needs sometimes it's not. It's even more foolish to think that you can tell from a E/I ratio, that's only one of the determining factors to cam selection.

IMHO that motor is missing A LOT of flow and some parts that just don't go together. Makes me sick to see guys going all out and not getting 400rwhp, makes you want to sell the LT1 and put a LS1 with a 232/240 cam in there and call it good. Same power less hassel. OTOH it's not that hard to get a driveable 420+rwhp out of a 383.

Bret

 

I believe Jim has plans for using nitrous... Thus explaining the split.

Jim baby, 370 rwhp in a 6 speed vette? I'm not even going there... Let me know if you need any help picking that car up. We would be happy to get your motor running the way it should be.

Good luck

Chuck

 

You are correct.. i divided by 114 instead of substracting 228.. I get 9.5º overlap.. correct... sorry

All im saying is that ... a change in cam might yield 15rwhp... i dont think it will make the difference between 480-380 as we should be seeing...

Im not sure, but I agree with you on that its not flowing correctly..

Even if they did flow the 330s and bad low lift numbers the car should have had around 450 uncorrected in his case.

 

You would be suprised on how little a duration change would make on that camshaft.

BTW Chuck, is either you or Eric a engineer? From what I can remember you can get sued if the title of your company includes engineering and you don't have a engineer on staff. I do but it's not going in my companies name. Just a tad bit of advice to you.

A race car builder by me had it happen so I'm not just running my mouth. So be carefull because it can happen. I don't know about you but I'm not willing to lose what I earned in my life over a name.

Bret

 

Maybe someone in the legal department could clarify this... I know I could probably name a few shops with Engineering in the name that do not have engineering degree's...

 

Well someone should tell them the same thing. Hey america's favorite hobby is the legal system.

When people assume I am a engineer I correct them, when people assume that my mother is a doctor she corrects them (BTW she is a nurse practitioner) personally I don't want to take credit for something that I am not, maybe that's just me though. A engineer is not something that falls out of the sky, it's something someone worked very hard to earn and I personally respect that.

I wouldn't get too revved up about the engineering thing anyways, it's not like I have met that many of them that actually know WTF is going on. The ones you do meet that know are rare and a great addition to any real automotive discussion. Luckily we have a few of them here (i.e. Fred and the older stroker)

Bret