marovetsm

iTrader: (24)

The 112 on my 4.8 came with a 3.9” making 5 lbs (with completely bone stock engine, exhaust, etc…) and now Im running a 3.3” which maxes out at about 9.5-10lbs with LT’s and small cam. Currently running 91 octane and meth which starts at about 7-8 lbs.

After next week Im gonna run E85 and no meth and I was wondering if I can/should go down to like a 3.1" when I switch over. I figure this would put my peak boost around 12lbs. Or could I go even more than that? My tuner does TONS of E85 vehicles with turbos/superchargers so I know the tune will be almost spot on.

Questions are-
What is the ‘sweet spot’ of a 112? Would the extra boost be offset by more heat?
How much of a gain would I see? Would it be worth it?
Will 6 rib and stock tensioned be sufficient? (this is not a daily driver)
With a stock bottom end is 12lbs+ too much with a roots type? I wouldn’t be worried at this level if I had a turbo.
If it was your truck would you do it or just stay at 10lbs and keep it 'safe'? Opinions/comments please

loloone

iTrader: (4)

I'm curious about E85 Radix setups as well!

Gadgetized

iTrader: (9)

Don't forget boost is basically the restriction in your engine. The more boost, the more heat, and less timing you can run. The best thing you can do is make your engine breath better so that it moves air in and out easier creating less heat. Has anything been done to the engine? I have a 2.9 pulley with all my mods in my sig. I am interested to see what a boosted engine is like with E85 too. Post up your differences in timing from 91 with meth vs E85 when this is all done.

scooter k

iTrader: (22)

Who's your tuner?

marovetsm

iTrader: (24)

I have stock heads, LT's with full exhaust, and a 217/219 cam with .533 lift. I want to take that out and put in a GT2-3 cam but that wont happen for a little while yet.

Tuner is Excessive Autosports in Sioux Falls, SD.

smokeshow

iTrader: (16)

If you're running E85 and a good tune, I wouldn't be afraid of putting 12psi to it. With E85 running properly, you essentially eliminate all possibility of detonation with stock compression ratio. You should be able to run all the timing you want. Like you said though, belt slip might be an issue at that point. Should be a fun ride.

quicksilverado

iTrader: (8)

e85 will compensate for a **** ton of heat. Over on ls1tech guys are running 20 plus psi and are running so much timing they are losing power and having to reduce the timing.

AKlowriderZ71

iTrader: (22)

I ran 11-12 psi on 90 octane for almost 2 years, on my 5.2(now has 150,000 miles). I kept the AFR in check, and the timing in check. No problems at all(besides the transmission).

If I had the fuel system for E85, and the fuel supply(can't buy the stuff up here), I'd switch over in a heartbeat, crank up the tune, crank up the boost, and see how far I could take it.

If you have the fuel system to support E85, do it. Don't worry about 12 psi on your 5.3, you'll be just fine.

marovetsm

iTrader: (24)

I think Im gonna pick up a 3.1" if I can find one in time, my tune is next Friday (5/6). Finding these is kinda tough since its the press on style instead of keyed. Im gonna call Magnuson today and see if they can hook me up. Last time I called the only size I could get was the 3.3 which is what I got. Anyone else know where I can get one? I know I can get a hub with quick change pulley setup but would rather just have a regular pulley if possible.

Ill be posting numbers and hopefully a dyno video next week after the tune.

EDIT: Just talked to Magnuson, 3.3 is the smallest you can get without switching the nose. So I ended up ordering a quick change unit with a 3.1 pulley. Ill doubt Ill switch pulleys much/ever but oh well it was my only option.

hellbents10

iTrader: (10)

I run a 112 and 3.0" pulley on mine with E85. I went from 450rwhp to 500rwhp just switching fuel and getting more timing into it. Also it is very consistent at the track with heat soak. Mine is a 5.3l with a 224 cam.