Uranium238

Going to be building an LR4 twin turbo motor for a 944 swap. Motor will have 317 heads and an LQ9 cam (given to me for free).

I can't decide on what turbo to use. Given the cam choice, top end power is limited to about 6000. I guess this means I should be going with a quick spooling turbo for a biturbo setup.

Any recommendations on turbos and piping sizes?

When it comes to power, ideally I'm aiming for a low boost 450HP give or take 10HP.

Cwarta

iTrader: (12)

The vs t3 61/63 .82 are are worth a look. $300 for billet, $200 for cast

Uranium238

It's a cheap build. Will have a look at the cast.

Are 60 lb injectors adequate to feed to boosting 7-8 psi?

Cwarta

iTrader: (12)

On pump gas I would sure think they would be.

chiaj144

iTrader: (4)

Unless you already have the 60's I would just decap the stock ones and run them.

JoeNova

317s are going to make power/spool TERRIBLE. Put the stock 4.8 heads back on there. LQ9 cam is OK, just make sure its an LQ9 cam and not an LQ4 cam.

Ebay 50mm T3s work very nice on a 4.8. You can get them for like $98 shipped without internal wastegates. Add $15 with internal gates.

roastin240

iTrader: (13)

If you want cheap and reliable, just grab a couple T3 turbos off a junkyard car. Run twin 0.63/0.60 T3's, would spool intantly and do 450whp but not much more

Could also run twin Grand National turbos, they have a 0.63 T3 with a T04 compressor. 2 of those would do 600whp max but comfortable at 450whp.

Could also go twin HY35 holset turbos. Those would do 700whp with 2.

And ya dont run 317's. The truck heads with more compression and smaller ports make more power on the 4.8 and 5.3...it was dyno proven back to back

gametech

iTrader: (1)

I am unclear as to why you think you would be limited to 6000rpm. The 4.8 likes to spin. Even the factory baby cam isn't choking too bad at 6k. Some boost isn't going to change that. That being said, don't lower CR for low boost, as it will hurt low end and spool without helping much else.

Uranium238

The LR4 I am looking does not come with heads. I wanted to make the 317s 'work' hence the turbo choice questions.

I will up the boost to 14 if I have to. Car will be using 91 pump but want to flash tune to 96 for Sonoma Raceway.

Choosing FITech for the EFI

mOtOrHeAd MiKe

iTrader: (8)

Doing ported stock GN turbos here.

JoeNova

317s on a 4.8 is 8.39:1 compression. Thats a full point lower. Spool, power, torque will suffer considerably. Get stock 706/862 heads and put back on it. They're cheap, and everywhere. I have probably 5 sets that I can't even give away because they're so abundant.

I still stand by my suggestion of cheap ebay 50mm turbos for $100/each. I put two on a buddies 4.8 S10 and it made 600 at the wheels. They spool almost instantly. There are 4 on the 4.8 in my corvette and I'm very happy with their reaction and power output.

gametech

iTrader: (1)

Since you are already halfway there, why not get 8 even smaller and cheaper turbos, then fab 2 brackets to mount them directly to the exhaust ports on the heads?

jordoza

Then run the exhaust from each turbo straight out the side like top fuel zoomies. You can be like street outlaws kamakazi. Lol. Youd probably get like ten million followers and your own show on discovery. No disrespect intended just saw the 8 turbo post and it popped into my head and i literally laughed out loud. Then the wife is like whats so funny and i explained just to get the well i guess you had to be there comment.

JoeNova

The ebay 50s are the perfect balance of availability/cost/output.

Good for ~400 HP each, use standard T3 turbines with 2.5" V-band downpipes, and cost $90-140 depending on options (Standard/anti-surge, either available in polished, all 4 of those options available both internal gated or not). All of the smaller turbos either cost more or use OEM 2/3 bolt compressor and turbine inlets and flanged downpipes.

Besides, who is to say I haven't been working on something like an 8 turbo big block concept, or triple supercharged LS?

gametech

iTrader: (1)

While we are all cracking jokes, OEM's really have explored individual turbos per exhaust port options with current direct injection setups. There just isn't currently any scenario where cost and complexity don't outweigh benefit. I still think individual turbos feeding ITB's would make for an outrageous show car, though.

Uranium238

Joe a 5.3 LM7 popped up on Craigslist near me. This one has heads on it. Should I use the 5.3 heads instead of the 317s off the LQ9 motor given to me?

I have changed my mind on the turbo. Going single T72 0.96 A/R P Trim, Dual Ball Bearing from CXRacing given the displacement bump. The LQ9 cam keeps the torque I will need where I need it on the course (not a drag car but a DE and potential SM class competitor in SCCA ST if the rules haven't changed against these swaps).

gametech

iTrader: (1)

This is just getting ridiculous. Please post your requirements (if class racing) and your expectations in detail. The more detail you provide, the more correct the responses to your questions can be. If your requirements are very specific, then also post a projected budget, time frame, and amount of personal involvement. The right questions get the right answers.

Uranium238

Just need help with the engine. This is my first swap but not my first track car. Came from racing 944s and now I want a much faster one after getting wind of swapping. So many choices.

The engine build will take a year and I want to cap my build price at 2500 including motor price and machining. I will assemble myself, NOT including the turbo stuff in that price which is probably another 1500.

Power goal is not to exceed 500HP on 91 but will remap to 96 if I get the gas at the track.

As for class... I will defer to SCCA for this.

gametech

iTrader: (1)

I don't have your answers, but you just opened the door for a lot of other people who might know them.

Uranium238

Glad to know I came to the right place. I need the education before I build the monster.