With 104 Octane (zero KR) and at a A/F of 12.7 on the dyno with the Fuel Trims Zero'd...I am not convinced that dropping the A/F 1/2 a point will do anything. I think the 104 offers some safety with its higher resistance to detonation. There are Turbo Applications running motors with a static compression ratio of 14:1 with high octane fuel.

 

Shinobi, I hope you know we just don't want you to break.

16psi + 104 octane (+ alky?) is aggressive. I would like to see you scale back your WOT A/F to 11.7:1.

 

No I know PSJ...I have gathered you guys aren't blowing smoke. I have been at this a while too but mainly I just no how to "monkey wrench" to the point where I have taken my own motor out in my garage without a lift on my Vette and put it all back together and it started the first crank..phew.

Anyway I don't have a laptop or LS1edit..I am thinking since I am all into this..I should start looking at getting that setup. Right now I don't really have a way to fatten it up. It would probably be easier to take 2 degrees of timing out of the program above 5500 rpms or switch to some AFR 76cc heads or have more material taken out of my LS6 heads...which if I am lucky would get to about 75cc. Either option would drop my current CR down from 9.67:1 to 9.3-9.4 perspectively. Than I would be at less risk. All my internals are forged (except for the crank of course). You really think I need Alky with 16lbs of boost an 104 at 12.7 Air/Fuel, 15 degrees of timing, and 0 KR?????
I appreciate the help.
Kevin

 

I would like to address several things on this thread if I may.

#1 With graphite gaskets you can either o-ring the block OR the head, not both, if you o-ring both the heads and the block the heads will "stand up" above the block and leak water like crazy.

#2 As far as I know, Rob was going through Cometic gaskets like underwear, once we 0-ringed his heads he never lost another gasket, Rob?? is this correct?

#3 Putting a receiver groove in the block is a band aid for an improperly o-ringed head with a copper gasket. If the o-ring is out of the head too far the heads will "stand up" off of the block and leak water, putting a groove in helps this, but if the wire is out the proper distance a receiver groove IS NOT needed.

#4 The cost for o-ringing the heads is $125 which includes surfacing the heads with a PCD cutter to obtain a smooth surface. (the web site is getting updated)

#5 Dyno disscussion, I have been running dyno's since my employment at Holley in 1993. We had a Superflow load dyno that would accelerated the engine at what ever speed you wanted i.e. 300 rpm/sec, 600 rpm/sec, etc.
The faster you accelerate the engine the less the load and the less the fuel that is required, consequently the slower the acceleration (due to the dyno loading the engine harder) the greater the load and the more fuel is required.

There are pros and cons to load (mustang) vs inertia (dynojet) dynos. You must understand that when you accelerate a Dynojet roller you are accelerating a given mass, we feel that this mass is roughly equal to 3000 lbs. If we tune a 2600 lb bracket car on our dyno to 12.5-13:1 it is too rich at the track, due to the dyno loading the car more then the track (3000 lb dyno load vs 2600 lb real load) Conversely if we tune a 3600 lb street car at 13:1 it is too lean at the track (3000 lb dyno load vs 3600 lb real load). With that being said a 3040 lb Z06 can run at a little leaner tune then a 3500 lb F-body. But I wouldn't run leaner then 12:1 on anything boosted, when I went 9.80's and was making 600 RWHP the A/F was at 10:1, when we went to the nitrous heads and made 690 RWHP, it was at 10:1, o-ringed heads, studs, broke everything in the car, $3000 Rossler trans, $1200 rear end, still didn't hurt the engine. I'm convinced if the tune is good you can make 700 RWHP with a stock shortblock for a long time. I hope my rantings help someone

 

Thanks Brian!
I think I heard the gavel drop after that post.

 

Great response.
I hope not to sound redundant but if my tune on the Z06 is 12.5 with Sunoco 104...do you think it is too lean of a tune if all the fuel tables are Zero'd on the Dynojet 248??? my fuel pressure is 54lbs and there was zero KR.

 

JamMasterJ,

You can get the ARP head studs for $240 from Summit Racing. The LS1 main studs are $157 i believe.

 

What you are asking here, I have seen you post this a few times, is the tune too lean if you short and long term fuel trims are zero'd out...

If the trims are like 1-2% then that's great, but your AF is still too lean for a blower or a turbo car.