Rise of the Phoenix

iTrader: (27)

Compression right now is roughly 11:1. I know with 93 octane and meth, that would be fine, but at the same time adding a meth kit just adds more money to the build. And if the additional flow of the heads isn't going to matter much on a boosted application, the 317's sound like a better option.

Tuskyz28

I wonder how a 317 head will do with a nitrous exhaust port deal on your turbo build.....

Game ova

If E85 is available where you live, I would skip the meth. Yes, you will need more fuel system....but it will be worth it in the end. And it would actually be cheaper to drive the car on E85. It's $1.59 here....and about $2.40 for 93 where I live. Yes, it does use more....but it's still cheaper.

Rise of the Phoenix

iTrader: (27)

Yes, fuel system will need to be addressed too. I'd like to do 80lb/hr injectors and some type of twin or bigger stock bucket pump. I'd also like to run stock fuel lines and regulator. Again, not trying to set any records with the setup, but realistically be around the 700 rwhp mark. I've read countless builds where it's been done by sampling using bigger injectors and an in tank pump.

ls1charged

iTrader: (8)

find a VERY good tuner cause 700whp is alot on a stock bottom 346, although it seems like people are doing it more frequently these days

Rise of the Phoenix

iTrader: (27)

The guy who will be doing the fab work will be my tuner as well. He's always tuned my car and does a damn good job. He and his partner have built and tuned the fastest LSx cars in the Mid-Missouri area and really know what they are doing.

Game ova

I see you are using a Monster stage 3 clutch. By the time you are done with your build, you may find yourself at the limit of your clutch. I believe it's good for 700ft/lbs. These turbo builds tend to be VERY torque happy...you may find yourself over 700ft/lbs. Which really is a good problem to have.

Rise of the Phoenix

iTrader: (27)

Yeah, the clutch has hardly any miles on it at all since the install, so it's just going to have to work until it either goes or I can afford a better one. I think it will be okay for a while.

SteenH

Yep spot on.

Dimeomboost

the 88mm is .96 ar just so u know its a perfect street turbo my wife is ordering one too stock block stock cube 346 man i just didnt like the on3 76 never tried the 78 but spec wise the 88 is near identical to alot of turbo manufacturers 76mm strwet strip budget 5-800 hp range

Game ova

I'm guessing the 76 made your ride feel flat on the topside?

Dimeomboost

backpressure was a big issue and like u said it didnt feel like it was gaining power after 5200 or so my 88 back halves like a beast of course its all 1/8 mile so not as impressive as others but still a 550$ turbi that fit under a stock hood on a t4 frame and 4" downpipe was pretty easy to work with now a pt88 or like turbo i could see being as u described as a street car but this little guy seems to love it

denmah

iTrader: (2)

7875
s475

do a pretty damn good job at 400$-650$

truckdoug

iTrader: (25)

anybody ever mess with that 77/83 Viren sells? not much info out there on it, been on the market a year.

been thinking about upgrading from my basic gt45 and not 100% sure I wanna chop up my up pipe for a t6 flange

ls1charged

iTrader: (8)

i had a ebay 7683 on my stock ls1 and traction was a joke, lightening fast spool! if you want crazy fast spool and less then ~550 hp thats the way to go on a stock ls1 IMO... only thing i didnt like was cruising on the highway at 80 in 6th gear if i breathed on the throttle i would see 1-2psi, if i did it over again id proli do a .96 and a small turbo cam to try to balance it out

JoeNova

Unless you have a 6.0 (and maybe even if you did), I would just go with the 7875. You can still make 750 wheel with a 6.0 and a 7875.

ls1charged

iTrader: (8)

agreed, a buddy had a 383 with a 7875 and was making ~650whp on 7psi

Rise of the Phoenix

iTrader: (27)

So on a 346ci, where would you see max boost with the ON3 78/75 and the ON3 88mm turbo? Also curious how much more the 88mm has over the 78/75 in terms of max HP.

JoeNova

I personally wouldn't bother with the 88mm for 700whp.
Its a copy of the old PT88 which is a pretty inefficient design. Big compressor wheel, small compressor housing, small turbine.

ls1charged

iTrader: (8)

i think the 7875 is plenty for your goal, id be more concerned about your motor living through it then the turbo size...