chevellepowered

iTrader: (37)

im not fully sure on the comp yet.. but i have done some research and found out that it will be in between 7.9 - 8.2 /1 ratio.. is that to low ??.. i have a twin turbo set up.. it will have full boost at 2,000 rpm,, kkr330 turbo's.. small.. what psi could i run safely on pump gas,, i will add meth down the road.. thanks..

Sluggish

iTrader: (10)

If its that low you should be able to make a ton of power on pump gas. I would think 800+rwhp would be easy on pump.

Darren P

iTrader: (1)

I am 8.25/1 and twin 20G's with the APS kit, 403 cid and it runs great. I am only running 9 to 10 pounds of boost and I figure about 725 to 750 at the rear tires. I havent figured out an easy to stop the inlets from collapsing or I would run more boost. I think my car drives great. I have been daily driving it for about 2 or 3 months. When I was building the engine people told me it needed more compression but it feels pretty good. Off of boost it feels much stronger than the stock engine felt.

DevonsZ

iTrader: (20)

if u have some good rods and crank 800 should not be a problem
im on e85 and my engine runs really nice around town and stays cool 180 190 on 80 90deg day
on e85 u wont have spray anything just cruise

chevellepowered

iTrader: (37)

yea i already have crower i beam rods 6.125.. i am using stock crank,, now i am looking at a single big turbo.. s400-75 t6-83... my turbo's only support up too 330hp a piece.. so 660 hp maybe 700 hp.. t6-83 support's 950 h.p..

Pro Stock John

iTrader: (34)

I was 8:1 and I think you could hit 800rwhp on pump gas with careful tuning, but I'd look at what timing you should run down low and in the mid range to minimize lag. I think a big single + 8:1 could get laggy if stock cubes, mine was.

MY99TAWS6

iTrader: (3)

On advice of my engine builder went to 9.5 on my 408. He did recommend that I run full time alc injection which plan on and e85 if we get it down the road.

I think the 9.5 makes it a bit less doggy and pretty sure can run 15psi or so on the alc with good timing and afr. Also more power from the higher compression if you can run the same boost level as the lower compression. I have no interest in running much over 20psi ever and likely should be able to run as said maybe 15psi and hit the hp goals I was looking for. Goals were 800rwhp on auto and 850 rwhp on m6. Still might upgrade the turbos not 100% sure yet. Then likely could hit goals at maybe 12psi or have more power in reserve if change goals.

darren I think you can stent something in there..Or just get the upgraded inlets .we spent this much whats another couple hundred?

I would like to see someone dyno with no inlets on there. it won't hurt for brief dyno runs.

I may try that next season .Would be nice to see just what these smaller aps turbos can do on my 408.Put some theories to the test.

Phil99vette

iTrader: (11)

Way too low. If your trying to run 10-12psi, I'd shoot for 9-9.5:1, gives you alittle room for more boost in the future. My motor we run 25psi and its @ 8.5:1, we're upping it to 9.75:1.

John_D.

iTrader: (2)

I'm running 8.7:1 currently, and it takes the first 5 psi of boost to make up for it... Well almost. I used to make 385 na, and with the low-comp block and the turbo I make 407 at 5 psi. Same heads and cam, same intake and exhaust, only differences are a low-comp block and a turbo in the exhaust stream.

At 11psi I'm making 543.

(those are all rwhp numbers)

Crowder

iTrader: (6)

x2

EPP

iTrader: (22)

Check out this build. http://www.exoticperformanceplus.com...Car.php?car=39
It runs a lot better than I thought it would with this much compression. Bob