408 Sleeper

I'm trying to figure out how far I can go with the power on the 408 Dodge.
The engine has 7:5-1 compression.
232-232 cam 110 LS, installed +4
Right now it is at 605 hp & 647 tq at 15 lbs of boost on 91 octane. The timing advance is at 36 degrees while in boost and still no detonation. Going past 36 degrees the power starts to fall off a bit. The advance in non boosted driving is in the mid 50's. I guess this is because of the low compression and the larger cam. I'm not really sure where to go from here. I don't know how much further I can crank up the boost? The factory block and cast Scat crank has me a little concerned though. Any Ideas?

Wilde Racing

iTrader: (26)

You are push much further than most have experiance in.... Once you hit the wall of timming gains it's time to crank up the pressure....

parish8

iTrader: (6)

i would crank up the pressure before the timing if your compresor has the flow but it sounds like you are keeping a close eye on things like when the power falls off and the knock sensor...

i would be interested in knowing what kind of power you would make at 15psi/36deg vs 17psi and something like 28deg.

how much power were you seeing as you bumped the timing from 30, 32, 34, 36? or whatever steps you went up in.

408 Sleeper

Each time the timing was raised from 28 degrees, the EGT's went down and the power kept going up. The turbo's are dialed way down and not even in the sweet spot yet. I just don't know how much more the block and crank will take.

parish8

iTrader: (6)

well. cant help ya with that one. turn it up and let us know

MikeGyver

iTrader: (5)

How much more obvious could it be? Turn up the boost until the first sign of detonation. Duh.
Seriously, how does your program indicate detonation?

408 Sleeper

The shop doing the dyno work uses EGT, wideband O2, the dyno and audible and years of tuning to detect detonation. They have never lost a motor so I assume they know what they are doing. Will I make the most power by advancing the boost as far as possible with the present timing, to just under the detonation point, or by going even higher on the boost while pulling the timing back?

parish8

iTrader: (6)

i can give some insight to an ls motor.

i tried 15deg of timing and as much boost as i could before knock. then i uped the timing to 19 or 21 deg and worked the boost up till i got knock. there was significantly more power at 15deg and more boost then 21deg and less boost.

i did gain power adding timing from 15deg up to 21 so it isn't that 21deg was just to much.

i think you could make more power droping the timing back a little are running more boost. that being said i dont know that i would try it. you are running parts that are as far as i know not proven at those power levels. it would be best to run some race fuel and ensure that there is no detonation and then turn it up. that way if it blows up you know you found the limit of the parts and it wasn't detonation that took them out.

if your set against race fuel then maybe some meth?

408 Sleeper

Thanks for the responses on this thread. I think that I will dial the timing back a couple of degrees and up the boost to 17lbs and leave it there for now. I have a new short block that is almost done. It is a Speedomotive U.M.B.R. It has Darton sleeves, Milodon 4 bolt mains, 3/4 hard filled and oiling and cooling mods. It will use a 4.185 bore with the 4" crank for a 440 cid small block. I have a Mopar Performance steel crank, Crower billet rods and some coated Ross turbo pistons. I will be raising the compression ratio from 7:5-1, to 8:25-1. The cam will be a milder 224-224 568-568 on a 113 LS and installed straight up. This combination should really allow me to crank up the turbo's to their sweet spot.

parish8

iTrader: (6)

^^^ with race gas i hope