i have a 383 sbc serious turbo motor 1500hp liquid to air gt47 88mm turbo and running race gas and need to know where i should run my timing it will be locked i have 632 lift cam and about 25 or so psi maybe more blowthrough carb from csu thanks i wanna start my car this week and try it if you guys could get back toi me it would be great

 

what hp goal, compression, convertor stall ,specific fuel, timing control system?

 

How do you have a 1500hp engine and don't know what timing it runs?

 

my thoughts exactly

 

I read it as he has a 1500hp intercooler.

 

Small block usually likes 32°-36° initial and start out pulling 1.2°-1.5° per pound of boost. Watch the plugs and give it what it wants.

 

I run my turbo sbc on e85 @ 32.5 degs under full boost 22.5 psi. About 11.3afr. I don't pull any timing!

Do yourself a favor & google search mark sullens on yellow bullet, and read up on some of his tuning advice on sbc e85 & boost. I think he talks some about racegas too.

My personal experience with my car was that it hated less then 28deg on e85. It would pop n bang out the exhaust with that kind a timing in it. I'd say, with good fuel & good air temps, you'll be around the 30-34 range, Sbc's love timing!

Do your homework, read plugs, start on low boost..

 

I think he is "Drag Chevette" on the bullet. He is an interesting guy with a different view on tuning E85. I dont have the guts to use his method.

 

Yup pretty sure that's him, he builds carbs for a living. I was timid at first too, told him he was crazy. But after 3 years of abuse, I'd say his tuning methods are solid.

A buddy of mine said, your nuts, no way you can 32.5 deg @ 22 psi. He had a fresh solidly built sbc, probably capable of 1100-1200hp last two 1/4 hits. Running something like 36deg initial pulling around 16-18 deg under boost. It grenaded @ 140mph, put a huge hole in the block. I think, because of the lack of timing, the exhaust valves got glowing red & bent, then the piston smacked them, the rest was history!

IMO, when you pull that much timing, it creates a retarded combustion event in the cylinder, & the exhaust valve is open, exposing the valve to extreme heat. Its my understanding the valve needs to be closed, & remain closed for a period of time to allow for complete combustion & cooling, before exiting. To do this, it's gotta have some timing in it. On reg pump gas, you might get away with that, but a good race fuel or e85, I think your asking for trouble.

 

You can run near n/a timing when inlet temps are at or below ambient.
I have seen many forced inductions cars with gen 1 sbc with water/air ic run lots of timing. And thats where they ran good.

Assuming you are gonna run c16 as your "race fuel". I would lock at 35-36 deg. Under boost I would start at mid 20s timing and work your way up watching plugs and performance data. Ive seen guys over the years that where non ic on c16 and would go to air/w ic and try and make pulls at the non ic timing they had the car tuned at.
The car would run badly. Some where in the low 20s timing and 20 psi non ic. By the time they had it running good it was in the low to mid 30s timing at same boost and bunches more power with the IC.