HotRodV6

iTrader: (6)

Ok, im in the process of gathering parts to build a 383 going into my Sonoma GT project, i have a 5.3 block that im gonna bore out the 3.905 with a callies 4.00 stroke crank and 6.125 rods.

Im gunna run some run some 317 6.0 heads, LS2 intake and 90mm Nick Williams TB, and plan to run atleast a single turbo setup, maybe twins, cant make up my mind on that part just yet.

Im planning to run E85 exclusively, and am building the engine with around 12.5 or 13.0 to one CR to get everything i can out of the E85.


My question concerns the cam for the setup, not sure what would be the best, im not going to be spinning the engine past 6500 and im gonna run a T56 trans with 4.56 rear gears and 29" tall rear tires, and i want all around good power, if i do a single turbo setup the exhaust will be a single 3.5 or 4in exhaust from the turbo back to the back of the truck. with a cat and muffler.


Thanks for the help.

HotRodV6

iTrader: (6)

TTT Little Bump

HotRodV6

iTrader: (6)

Ok, heres some specs on a couple cams im thinking about, the first one the same one im putting in a iron block 408 im building to go into a friends 96 S10 with a T56 trans

.550/.550 218/218 @.050 117 LSA

The other one is

591/581 228/232 @.050 114 LSA

Im leaning more towards the second one, and this place in dallas were my buddy got some of his parts to build the 408 calls it an F1 cam, not sure if its an off the shelf comp grind or anything.

Im thinking it will do well with the turbo, running 15 psi.

Any thoughts?

hammertime

iTrader: (1)

I don't know man, 12.5 or 13:1 sounds awful high. You do know E85 is only 105 octane, right? I checked an online boost compression calculator, and 12.5:1 with 15 lbs of boost comes out to 25.26:1 - way too much!

Also, 317 heads have a 72cc chamber, and even on a 383 will not get you anywhere near the compression you're talking about without a serious dome. 59cc heads would get you a 12.68:1 static compression ratio, but even with E85, you can't boost it the way you are suggesting. You'd make plenty of power N/A with the second cam you chose, but I don't see it working with boost.

I would recommend you call one of the board sponsors who deals with turbocharging on a regular basis and get some first hand info, they can probably recommend a camshaft as well.

JakeFusion

iTrader: (7)

I'd aim for 8.5:1 CR and run more boost and timing. That'll make more power in the end. Be warned, though, that iron blocks don't allow the same amount of timing as the aluminum block brethren if it at all matters to you (even though it's less of a concern with the LSx platform as it responds differently to timing versus other engines).

Certainly 15lbs is doable with 93 octane at that CR, so E85 may support upwards of 18-20psi with the same timing (but I'm not sure - not in an area where E85 is even available, so I've never experimented with it).

Good turbo cams are generally single pattern... but I'd probably bump it up to a 224/224 114 or so and maybe even more for the 383.