Rick@Synergy

iTrader: (5)

Did you have the block decked when you had it machined as well? Sometimes people assume they are flat from the factory, which is far from the truth.

Rick

01Bird_of_Prey

Well, I going to pull the head off and have it checked. I'm running a 3.40 s/c pulley through the twin intercoolers. I dyno'd it orignially at 10psi and made 610rwhp and floated the head then, too. But I have not dyno'd it since 17psi.

My fuel system consists of twin 255's msd boost-a-pump, 1/2" all the way up to aeromotive rails through motron 60's, return aeromotive boost ref regulator 3/8" back to the tank. I don't think that fuel delivery is a problem, but after speaking to my tuner guy he thinks that it could be detenation and that I need to run race gas with this much boost. Now I'm thinking that I want to back the boost down to 14psi.

If anyone has a larger 8 rib sc pulley for sale - let me know.

By-the-way, the sdce 8 rib setup is unbelievable - I have fought for 2 years just trying to make 11psi and keep the belt from slipping. I highly recommend it - Don't waste your time and money on anything else.

Thanks for everyones help on this post.

Pro Stock John

iTrader: (34)

With a smaller engine, I have held 21psi with GM MLS 6.0 head gaskets and a set of ported 6.0 heads. No o-rings.

But we are dynoing with C16.

What was your peak timing? I hope it was like <15 degrees with the D1sc twin lil' coolers.

383LQ4SS

iTrader: (33)

Danny...pull the heads and check for a good surface, put new gaskets on, and redyno at 17 psi using a high octane gas. I bet you they will not lift.


BTW..I made 750 Tq for a year and a half on the same gaskets. Its all about detonation control and good gas. If u have ZERO detonation...you will get away with more than you ever thought. Look at Harlan.

Rick@Synergy

iTrader: (5)

Not sure if anyone has mentioned this yet, but if you had a problem at 10PSI floating the head, what made you upgrade to 17 PSI? I think there is more going on than you think. This could get bad on the motor real quick if this is the second time. Its not time to pulley down, more like time to check the deck and the heads. Dont o-ring your setup. That is a bandaid to a problem right now and it wont cure it. Are you getting knock on your runs?

Rick

MelloYellow

How many Torque sets on the ARP studs?
How much Timing are you running?
Engine C/R?
Do you have a FP gauge?
What are IAT's under boost?

Pro Stock John

iTrader: (34)

Lot's of potential culprits here:
-poor deck to head clamp; redeck block and cut the heads
-improper torquing of head studs
-detonation due to total compression requiring less timing or more octane

Questions for you:
-How compression is the engine?
-Peak timing?
-93 pump gas?
-Cam?
-IAT's at the top of a dyno pull?
-Twin ATI intercoolers, the stock ones?

Rick@Synergy

iTrader: (5)

The other thing I Would do is ditch that twin ATI setup. That is killing your IAT's and your potential very badly. And if you are under 17PSI, those IC's wont even come close to working well.

We sell an FMIC kit if you like...

VINCE

iTrader: (1)

Interesting.. I would also contact APE to get some of those L-19 studs. I have them and I have hit my car pretty good on the spray on pump gas and I have not lifted the heads. I have seen 700rwhp on my first stage with no sign of lifting the heads on pump gas. I would pull that head, clean the surface, change gaskets, retorq it back down,add 100 percent 100 octane, and redyno.

Pro Stock John

iTrader: (34)

17 psi + those small 'coolers + 93 pump gas is really a stout combo, pump gas does not have infinite octane power like some folks seem to think.

VINCE

iTrader: (1)

I agree John.. Danny lives local to me. Most of the cars around here like to claim pump gas, but to reach the power levels we want you will need race gas. I tested my nitrous on pump gas first to see what she would do b4 detonation. 700rwhp is the limit on pump for my combo. To go any further I need atleast a race gas mix or reduce more timing. I am sure Danny will figure out what the problem is soon enough.

SDCE

sent ya a pm......

Armageddon

iTrader: (41)

I would like to know this also...
Sounds like detonation, find your problem before you blow your crap to pieces!

Pro Stock John

iTrader: (34)

17psi with a 408ci + stock baby 'coolers + 93 pump gas sounds problematic (was my comment above which may be a little vague). That does not sound like a safe combo, unless the engine compression is super low.

01Bird_of_Prey

I pulled the heads off yesterday - definetly something went wrong. The bottom side of the gasket looked as if it was movig around. I will try to get pics and post.

As for your questions - compression is 9.1:1 I think. I have 30cc dish pistons, 60cc heads, a 4" bore. Peak timing was 22 degrees, 93 octane gas. I'll have to get cam specs. IAT's have not dyno'd the car. It does have twin intercoolers (stock).

I did not want to run this much boost anyway, so what is the most boost that I can run before falling off the edge??? Originally, I only wanted to run 14 psi peak.

LSs1Power

iTrader: (5)

14psi should work with your setup really great OR get a alky/water injection to aid the stock Intercoolers to allow you to run the 17psi you want to run. I think 17psi, 22 degrees on pump gas with the stock intercooler cooling the air that is going into the 9:1 C/R is too much. Did u ever log your IAT at that level? How about knock?

gator's 99TA

iTrader: (2)

wow 22 degrees of timing, small intercoolers and 93 octane? damn that is a HOT charge! i understand teh coolness of pump gas and all that. esp on teh streets of tampa, but i dont see many people making that kind of power on 93. esp if you want to make the power consistently.

Pro Stock John

iTrader: (34)

22 degrees sounds like way too much.

I was running 23, Griffin FMIC, ~20 psi, and 110 and now C16.

I'm thinking you need to pulley up for less boost, or run race gas, or start off next time at like 14 degrees of timing.

Armageddon

iTrader: (41)

I agree with John. Your playing with fire.

Pro Stock John

iTrader: (34)

It's possible the heads lifted right during the first dyno pull. I think you want to keep the IAT's well below 150F.