Sideways7

iTrader: (7)

I hate asking another "Help me size my turbo" thread, but I can't find what I'm looking for. Feel free to blast away, but I'm lost!

First, the car: S4 J-spec block, fully balanced s4 turbo rotating assembly, half-bridge from BDC, HKS log manifold, 3-inch full exhaust, large v-mount intercooler, Megasquirt MS3X, 550/1680 injectors.

Long story short, I destroyed my turbo. I took it to the local turbo shop (Majestic Turbo in Waco) and he told me that there was so much axial shaft play the the only thing salvageable was the turbine housing. Needless to say I'm in the market for a new turbo.

My goal is 500-550 RWHP eventually. I had a Masterpower T-70 (basically T-67 inducer, T-70 Exducer) with a .96 a/r. Based on my limited experience with it I was pretty happy with it. It hit 1 BAR at 4700 RPM - the spool could have come quicker, but I think that's partly a tuning issue and partly because I had a catalytic converter. Peak boost was at about 6k then it trailed off.

I'm wanting to keep things on the cheaper end of the spectrum. The shop does all manner of hybrid/custom turbos, so I'm pretty open on my options. I'm just trying to get a handle on what different sizes will do. Mostly, I'm trying to get a grasp on how the bridgeport effects the turbo characteristics as I'm reading conflicting information.

Should I stay with a p-trim wheel, or bump up to something like a GT40? I felt like it was being choked a little up top, but again that could have been tuning and the cat.

On the compressor side, with a p-trim wheel, he was recommending either a t-67 or t-70. Do you think I could get to my goals with a t-67, or is that pushing it? If I go the the t-70, is there really that much later spool?

If I go with a GT40, will that basically shift my powerband further up, or will it have similar spool? Then I run into the problem of those only having divided housings with my undivided manifold.

Help!

Shainiac

iTrader: (7)

I didn't see any mention of added studs or upgraded bolts. I would reconsider your power goals with that S4 block.
Also, what is your budget? That's probably the biggest factor.

I would avoid the GT40. They're old tech by todays standard and there are better options for less money. I had a GT40R and was not impressed with response. After moving to an EFR 9180, the GT40R flat out stinks.

Sideways7

iTrader: (7)

Sorry, not sure how I left that out - the engine does have a stud kit.

When you say that there are better options for less money, what are they? My budget is the less the better. I really don't want to spend over $1000, and it would be awesome if I could find something less than that.

I would love an EFR, but it's outside my price range. What about a S366? With my un-divided manifold it appears I'd have to go with a .88 a/r housing, but the turbine wheel is larger than the p-trim on my old turbo I guess that would partly cancel it out? I just want to make sure that wouldn't choke the engine up top.

rodney007

Hi would recommend the following:

Borg Warner s300sx - Model: #177281
Compressor
Wheel inducer 66mm
Compressor outlet 3.00
Compressor inlet 4.00
Turbine
Exducer 73mmTurbine outlet 4.00 V-band
Housing T4 open flow .88 A/R

Borg Warner Turbocharger SX S300SX3 S366 66mm T4 .88A/R 320-800HP 177281 | eBay

I am using this turbo and am very happy. I am laying out a responsive 400hp at the wheels at only 14psi and
best of all its very responsive and has minimal lag.

Its also capable of well over 600HP. Just make sure you have at least 5000cc of fuel NET (1600cc/1000cc combo works good with little to almost no secondary change over).

This turbo is very cost effective and reliable, cant say enough good things about it and its very commonly used with our setups.

I would also recommend a 50mm (at minimum) external gate. I have a 50mm pro-gate and it holds 14psi perfectly with no spike or drop at all.

If you need any more help with your setup PM me and I am happy to helpout as much as I can.

Sideways7

iTrader: (7)

Thanks! That's exactly the one I was looking at. I have decided to go with the. 94 AR divided, though. From what I've read there's little /no penalty in using with with my undivided manifold now, and will be better whenever I can afford a better manifold.

As for the gate, I have a 46mm precision unit. I'm going to cross my fingers that it works! I'm staying down on power for now until I get more injector. I'll be very happy with 400 for the time being, I just want the room to bump it up once I finally go e85.

rodney007

The gate should be ok and you have plenty of fuel for 400HP on that turbo.

What kind of power were you putting out before on your old turbo setup? has your block been studded yet?

Anything close to 500HP is v.risky without it on s4 block.

WANKfactor

iTrader: (1)

You can run a split pulse turbo on an undevided manifold. Just sayin.

Sideways7

iTrader: (7)

Yeah, that's what I'm going to do. I thought I had read not to somewhere, but a quick search showed that was wrong.

Yeah, its studded. I previously had a BNR stage 4 that was running 18 psi. Never dyno'd, but guess around 350 at the wheels. Meth controller failed and popped the motor, rebuilt and it ran well, but lost faith in the AI controller. Then it sat for a while (2-3 years) until I figured out what I wanted to do.

It's only had the masterpower on for less than 500 miles and I was still tuning it so I never got to take it above about 6k at full throttle. It felt nude around town, but I think thats because the megasquirt is so much better than the E6X I previously had.

GoodfellaFD3S

iTrader: (213)

Which meth controller failed? Run water injection (windshield wiper fluid) with an AEM setup, they've proven to be bulletproof. Enough for low 500s at the wheel on 93 octane with your proposed setup

Howard Coleman

iTrader: (6)

"Run water injection (windshield wiper fluid) with an AEM setup, they've proven to be bulletproof. Enough for low 500s at the wheel on 93 octane with your proposed setup"

100% agree.

water or water/meth works fine. 500 CC or thereabouts reduces/eliminates detonation while cleaning your internals.

"Meth controller failed and popped the motor"

i prefer 100% methanol for 500+. since methanol is a fuel the AI system should be top notch...no plastic lines. i have run the Alkycontrol system since 2003 with no system failures. the proprietor of Alkycontrol, Julio Don, is a certified Electrical Engineer and the system reflects it. besides high quality electrical, all the plumbing is braided stainless steel.

running 900 CC of meth (nearer the higher end of our needs), should you lose delivery you would experience a 10.7% uptick in AFR from 10.7 to 11.4 at the 500 hp level and an 8.8% increase at 600 hp, from 10.5 to 11.42.

meth atomizes in the UIM taking IATs down to the point that the UIM is cold to the touch after a pull. like water, methanol squelches detonation and cleans engine internals.

run water, run water/meth, run meth.

as to turbo, either the S300 63 (177283) or the S300 66 is an excellent budget choice.

Sideways7

iTrader: (7)

Devils own. There was no obvious indication that it had stopped working. I warrantied it, sold it, and replaced it with an AEM unit, which worked great. However, I was using it to get more power out of a hybrid turbo which was too small anyway. Decided I could get the same power more simply with a proper turbo and down the road when I want more I'm going to go e85 as it is readily available around here. MS3X has flex fuel capability, so I'm not reliant on finding it.

The other reason for being rid of it is that I plan on running the car in HPDE, and possibly some NASA, events and even at below 50% meth it was an extra headache I didn't want to mess with.

Edit: thanks Howard; I actually got started on aux injection from BDC who showed me that exact setup. I remember being VERY impressed with it when I was in his car but chose not to use it because of the difficulties of running it on a racing circuit. I absolutely love the idea of meth injection, but for my needs straight e85 it's just going to be better suited.

arghx

iTrader: (3)

HKS cast Manifold? That thing sucks, get a better one before you look at turbos. Boost control is horrible on it, wastegate runner is undersized.

Sideways7

iTrader: (7)

Yeah, Its not great but it works until I can afford something better. Any recommendations on a better manifold? I cant afford the Turblown unit right now, and don't want to waste my time on ebay crap.

Edit: there's and RE-A manifold up for sale. I'm about to jump on it unless someone knows of a problem with those.

Sideways7

iTrader: (7)

Well, I couldn't risk someone else getting the manifold so I grabbed it. It looks functionally identical to the greddy/feed manifold I've seen pictures of. I'm just going to have to get a new wastegate flange welded on and hopefully my downpipe is close. A bit worried about it hitting my newly located v-mount, but I'm cross that bridge when I get to it.

I also ordered the turbo. Thanks for the help and advice! Also, I think it's quite funny that it is the exact part used on a John Deere tractor.

Blaster5337

iTrader: (7)

I'm going to run s366 on my half bridge with aem water meth. 366 is great for a budget under 1000 and with the appropriate fuel system should have no issues putting you in the 500s on hp. I would go full twin scroll manifold with dual 44 mm gates to prevent boost creep at higher rpms. Rotary werks and turblown engineering makes a really nice twin manifold. Or you can go with gleasmen for that super sexy manifold.