slow ride

Thinking about ditching my 383 H/C stuff and doing a mild twin turbo build. I hate to dismantle a good running 383, but you know how it goes, things just get old. It's been running for 4-5 years and probably 3 at 500whp. It's either do this or go big cube, but I have a lot of experiance with FI and figured my block can take a little more abuse than I'm dishing out right now.

Plan is to sell the heads, Fast 90/90mm tb, headers, intake, etc to offset some of the cost. Might try the cam I have now (238 242 114) to see how it works, but it's a little big and I'd like to calm things down some. Run either a ls2 or 6 intake, cleaned up 317 heads, stock type manifolds and build from there. Either tuck them in or put the turbos out in the fenders.

I'll do all the work myself and it's a long list, but nothing I haven't done in the past. I've got hookups on turbos, pipes, fuel parts, etc so it's not that bad as far as parts prices, but lots of my own time. Not looking for crazy power as I don't feel like messing with all the drivetrain swapping, etc. 700ish on E85 and 600 something on pump would be fine with maybe a little room to grow. I want it to be responsive though so sizing turbos accordingly.

One thing I don't like to think about is not being able to run the car at track days due to heat managment. I'm wondering if you turn the power down some and run e85 to help with cooling if you could get by with mild tracking of the car as long as proper heat wrap is used and it's not really hot outside, etc. This would only happen from time to time as I don't get a chance to do it more than once or twice a year.

Sound crazy

jobberone

Be a lot simpler to throw a SC on what you have. What's your current CR?

You should put a bigger radiator in if you're worrying about heat. Running E85 is fine if you can get it easily. OW you're better off with 93 and meth.

DOUG @ ECS

We do it all the time here.

Corvette-Chris

I've done the exact thing.

A few years ago I wanted to go FI when I had ported AFR heads, ported Fast 90/90, big NA cam and all the nitrous goodies you could think of. I sold everything but my forged shortblock, including the heads, intake, cam, etc and bought stock 317's, stock LS2 intake, new turbo cam and the turbo kit.

I have never for a day regretted making the switch.

slow ride

Not looking for superchargers just because I like how the turbos quiet the exhaust and the midrange torque punch. Aside from the fab work on my part the cost will not be that bad after selling all my H/C stuff. I know they can be just as fast, but I want the ease of control over pressure, etc.

Any of you turbo guys still able to track the car at lower boost levels? I figured with e85 helping keep things cooler than gas and low boost it wouldn't be that bad, but I know how turbo stuff heats up and it's hard for non factory engineered parts to hold up over time. I'd use all the heat blankets, etc to make sure things don't melt around the turbos and go the extra mile to support everything so it lasts.

The shortblock is a mahle, compstar rods and eagle crank deal. Compression is 11.8:1 and will drop to 10.0:1 with 72 cc 317 heads (I might work them a little to drop that number a little more). The pistons are not a big boost piston, but I did build it with a little extra clearance for nitrous (which I never used) so I'm sure everything will be good at the lowish goals I have. I'm still up in the air over the whole deal, but one of these cold winter days I'm sure I'll just start gutting the engine just for something to do.

slow ride

Yea, E85 isn't a problem as I live in Iowa Just sucks I'll probably need 1000whp worth of fuel flow to support 700ish whp on E85, but I know I'll kick myself later if I don't set it up to run on corn.

marco383

I went from a 520 RWHP 427 (C5R block, ported LS6 heads, 11:1 C.R.) to a Procharger F1C setup. Wasn't cheap, since I swapped for LS7 heads and intake, blower pistons, billet rods, and a blower-friendly cam. I picked up 180 RWHP running only 8 psi on 93 octane without meth, and stopped there, not wanting to blow more money on fragged driveline parts.

I haven't tracked the car since going FI, but it runs cool on the street in 90 degree plus temps with a BeCool radiator and a 176 thermostat.

jobberone

I consider FI specific pistons and rings as vital to a build. If you run relatively low cylinder pressures then regular pistons will last for awhile but its not the best idea.

slow ride

Guys have made way more with stock junk (not that they will last forever either). I'm looking to make 6-700whp so I'm not that worried about it. If it breaks I'll fix it. Tunning is the most important thing.

jobberone

If you're into the engine I'd put FI rings and pistons in it. If you're just changing heads then I understand esp with low boost.

slow ride

Yea, not planning on opening the bottom end up. Pistons are Mahle 4340 with the standard Mahle ring pack found in the power pack. These are still going to be better than any factory ls piston (maybe not the ls9's). Rings are gapped a little loose and piston to wall clearance is .001" over the standard. Not to mention the engine has almost 15k on it. I'll look over things when I open it up, but if the bores look even just ok I'll run it for now.

Looking at turbos in the t3/4 50/60-1 range, but not sure on the exhaust side. These are all close to the ttix kit size, they they are BB. Don't want the .63 a/r housings choking off the top end since it's going on a 383 so I'm not sure if I went with .82 housings would it still be responsive with the journal bearing? If I run the fender mount I could probably fit full t4 stuff so upgrades are just a swap away. I'll have to cross that bridge when I get there.

jobberone

I don't think you need bearings to be responsive. It depends on how long you plan to keep the car/turbos yada. I'd go with the T4 if I had a choice but smaller is ok as well for your use. Unless you're going to strip it a lot you can really only use so much HP on the street.

slow ride

Yea, being a 6 speed and running c5 trans/rear junk I know the drivetrain has it's limitations. Aside from the stock pinion support and c6z right shaft it's got all the good rpm c5 stuff in the trans and rear. I was close to buying a 6060/c6z drivetrain, but just don't feel like blowing the cash on it.

I'm sure if I de-cam the engine and with it still being 9.7-10.0:1 it will have plenty of low end grunt off boost. It will just be funny to see people look at me weird filling up with e85 at the pump

QUIKSILVERZ

i am in a similar boat. i removed my fast 92/ls2 combo, UD pulley and big N/A cam a month or so ago. Went back to stock ls6 intake/tb, stock pulley and put in a G5XB camshaft. It was nice calming down the street manners with the blower cam and picked up HP/TQ across most of the rpm until 6500 rpm. I am looking to install a ECS NOVI or A&A YSI supercharger kit though.

slow ride

I hear you about driveability and cams though. You want to go big enough to make the NA combo shine, then later on you start to think that jeez if I only went a few degrees smaller Seems like every car no matter the tuner can't make the big stuff perfect (at least from my experiance). Some people are fine with the little issues, but as I get older I just don't care for it. If you are picky you'll notice all the little things over time and different conditions.

I'll either sell my cam or have comp regrind it to something in the 225-230 range and use xe lobes for longer valvespring life. Car should pick up a lot of off idle response and still drive well since it's a little bit bigger engine than a stock 347.

MVP'S ZO6

Sounds like you have all this already planned out really.

slow ride

I guess I was checking for reasurance in moving forward. Something that requires more of my skill to develope and maintain. I wouldn't mind building some sort of drag car thats easy to work on and fit a larger single turbo, but don't really have the space for another toy right now and can't stand not driving the cars on the street a lot. I don't want to look back as say "damn I should have left it alone and enjoyed the simplicity of the NA setup". Lots of guys seem to sell there crazy setups and just buy a newer car that they can drive without worring about everything. I'm guilty of selling old projects in the past even if I had them running well and ironed out. It's different when you do your own work as you don't go broke fixing up any of the loose ends.

My other plan was a large cube NA deal, but thats not going to happen with very many of my current parts so I figured this way I could make use of some of the old stuff and end up with something a little faster with my own personal touches on it.

Feedback on turbo size that others have tried and being able to still track the car some were things I wasn't so sure about. My guess is that tracking will not be likely unless it's on a very cool day and lots of thermal protection. I have friends running e85 in stuff around here so I can tap into there experiance for tuning with it.

chevylad

I spun a bearing on the stock LS1 and bought a 402, but with a 63cc head and the compression was about 11:1. Now, I have a set of 317 heads and a slightly thicker cometic head gasket to bring my compression down to about 9.8:1.

A few years back it just wasn't good idea to run boost with a high comrpession ratio. With a meth injection and an intercooler it makes it easy to run high boost without detonation.

It's hard to beat the bang for buck with a supercharger. Ultimately, it was the cost of the Fast manifold that changed my mind on which direction to approach.

slow ride

Well, picked up a set of 317's that just had 30 passes on them since the light decking, SS valves and a valve job were done. Plan to clean them up, mild port/ bowl work and either run them or sell them. It's a start towards making the switch though

Corvette-Chris

Very cool man!
That's what I am going to do to my heads. I need to replace the valves and I'm going to do some bowl blending and then get a valve job and they should be good to go.

You're on your way...