Single turbo sizing

[WDBi]

So ive been looking into buying the doc race manifold which should be out soon here or having a custom one made and putting on a turbo i am happy with. My goals are 750-800whp. I want to do this on just e85. I have been looking at the gtx3582r, 6466, 6766, 7175, and the gtx4088r which will be released in a few months.

I want to make 750-800whp with the fastest spooling turbo but i also want a turbo that makes that power efficiently. The gtx3582r will max out at 750 so it will spool very quickly but ill have to run more boost than say the gtx4088r. Are there any turbo sizing gurus out there who could help me out here?

[MDORPHN]

Can't reply intelligently without knowing how you plan to use the car. Street, 1/4 mile, road course...

Neil

[WDBi]

Can't reply intelligently without knowing how you plan to use the car. Street, 1/4 mile, road course...

Neil

street maybe with a few 1/4 runs here and there but mostly street car/ highway killer

[bigdnno98]

Look into the forced performance HTA3586r. Short of a Borg Warner twin scroll the HTA will be the best turbo you'll find

[bigdnno98]

You're going to have to decide between fast spool and max power. You said you want 800hp. Be advised, 800hp turbos do not spool fast. Everything is a compromise. Twin scrolls are made to reduce lag while compromising little HP up top. Gt40s will get you there but be laggy as hell. That HTA3586r with 1.02 turbine housing is one of your better options I think. I'm personally not a fan of precision turbos.

[Payam@BMS]

http://www.full-race.com/store/turbo...374-turbo.html

http://www.compturbo.com/products/ct4billet/ct4_6465

http://www.precisionturbo.net/Street...-CEA%C2%AE/480

Still will depend on where the turbo will sit and exactly how much room you have. 800whp will need a big turbo, so you need to put that into consideration.

[bigdnno98]

http://www.full-race.com/store/garre...86r-turbo.html

[benzy89]

If you're looking into a 750-800 WHP car running on E85, I think you need to make sure you have the necessary fueling system to achieve those goals before you worry about which turbo would best fit.

BUT I think you'll have a lot more fun with a GT35R since it'll give you a wider, more driver friendly powerband instead of the quick, spikey power you'll prob get with a GT40. Obviously a lot more factors to consider like the turbine, ball bearing, etc etc. Obviously the only way to get the best answer is speaking to someone who's qualified, specifically who knows the N54 really well & can read compressor maps.

[rudypoochris]

I think you're spool will be so long at that power with an ST that its going to be quite tough to be a highway killer unless you plan to brake boost all the time. I would look to a twin scroll with a quick spool at least.

[bigdnno98]

+1 I think you fastgti and I all agree twin scroll Borg Warner would be first choice. Quick spool kit would be a nice little toy too.

I think you're spool will be so long at that power with an ST that its going to be quite tough to be a highway killer unless you plan to brake boost all the time. I would look to a twin scroll with a quick spool at least.

[WDBi]

I understand it wont spool quickly but i would just like it to spool the fastest a turbo making that power can.

I have come to a decision that a 35r is too small i want the turbo to be able to make 800whp and i dont want to be maxing a turbo out. There is alot of good word about the 6466 http://www.supraforums.com/forum/sho...precision-6466

so right now im between the 6466, 6766 but i think i would prefer a 6466 over the 6766, That borg warner efr 8374 looks nice but arent those turbos alot bigger than a equivalently sized precision?, and maybe a bigger hta?

[bigdnno98]

I understand it wont spool quickly but i would just like it to spool the fastest a turbo making that power can.

I have come to a decision that a 35r is too small i want the turbo to be able to make 800whp and i dont want to be maxing a turbo out. There is alot of good word about the 6466 http://www.supraforums.com/forum/sho...precision-6466

so right now im between the 6466, 6766 but i think i would prefer a 6466 over the 6766, That borg warner efr 8374 looks nice but arent those turbos alot bigger than a equivalently sized precision?, and maybe a bigger hta?

Borg Warner and Forced Performance quality are so leaps and bounds better than precision that its not even a fair comparison. Most people run PTE turbos because they're cheap. Period.

[bigdnno98]

Full race is widely known as the best turbo kit maker in the business. They don't sell precision turbos for a reason.

[WDBi]

Full race is widely known as the best turbo kit maker in the business. They don't sell precision turbos for a reason.

hahaha well ok so i feel like a noob here but ive never known what a qsv is my mind is blown now...

i now want a turbo that could possibly make 900whp maybe just 850whp just so im not maxing out a turbo. Put down around 800whp with a divided housing and a qsv that was i have a turbo thats spooling as fast as it can in that hp range and then im making it twinscroll and qsv and all i would do is run a bit bigger a/r to make up for the top end loss

[bigdnno98]

hahaha well ok so i feel like a noob here but ive never known what a qsv is my mind is blown now...

i now want a turbo that could possibly make 900whp maybe just 850whp just so im not maxing out a turbo. Put down around 800whp with a divided housing and a qsv that was i have a turbo thats spooling as fast as it can in that hp range and then im making it twinscroll and qsv and all i would do is run a bit bigger a/r to make up for the top end loss

Sound like a plan. Just keep in mind more ar=more lag. I'm currently looking to switch from .82 to .63 to gain some spool. Since I'm not maxing the turbo out up top I don't think ill lose much top end. You won't have to worry too much about that with twin scroll.

[WDBi]

Sound like a plan. Just keep in mind more ar=more lag. I'm currently looking to switch from .82 to .63 to gain some spool. Since I'm not maxing the turbo out up top I don't think ill lose much top end. You won't have to worry too much about that with twin scroll.

i plan on just raising ar a bit due to the twin scroll and the qsv taking a bit of ar away just due to the division this way i get to keep my top end instead of loose it due to the qsv and the divided housing and then when the qsv is closed i still get fast spool

now to decide on a turbo

i guess precision is out the window so its down to GTX40 because the 35 is too small and borg warner?

[bigdnno98]

BW is your best bet. They are the twin scroll experts. Do not discount the HTA3586r. It is bigger than the standard 3582r but with the HTA technology it spools like the normal 35r. It'll get you to 800hp.
Here would be my list for a DD 800hp 335i twin scroll setup

http://www.full-race.com/store/turbo...374-turbo.html

http://www.full-race.com/store/garre...86r-turbo.html

http://www.full-race.com/store/turbo...-gtx4202r.html

you want to stay away from going bigger than you need. Get the size turbo you need and let the turbine housing ar decide low end or top end.

[WDBi]

BW is your best bet. They are the twin scroll experts. Do not discount the HTA3586r. It is bigger than the standard 3582r but with the HTA technology it spools like the normal 35r. It'll get you to 800hp.
Here would be my list for a DD 800hp 335i twin scroll setup

http://www.full-race.com/store/turbo...374-turbo.html

http://www.full-race.com/store/garre...86r-turbo.html

http://www.full-race.com/store/turbo...-gtx4202r.html

you want to stay away from going bigger than you need. Get the size turbo you need and let the turbine housing ar decide low end or top end.

i think a gtx42 is too big and the 35r im just still scared itll be too small i think the efr 8374 is ideal is there a reason they dont offer twin scroll?

[bigdnno98]

BW offers the 8374 twin scroll. That's how it's sold primarily.

[WDBi]

BW offers the 8374 twin scroll. That's how it's sold primarily.

Hmm another question... how would i run a wastegate and bov with this its all in the turbo?

[Snertz]

Hmm another question... how would i run a wastegate and bov with this its all in the turbo?

You could either utilize the gate setup that comes with it and convert the car to controlling it via boost, or adapt one of the N54 actuators to it and keep it vac operated. Should take just a new bracket to use the N54 actuator. In either case, you'll need a manifold that isn't plumbed for an EWG.

For the BOV you can just plumb the line that usually goes to the stock DVs to it and block off the ports on the chargepipe (maybe a N55 chargepipe would fit?), or get the blockoff plate for the turbo and keep the BOV/DV in the stock location.

I noticed that Full Race doesn't have the TS T4 housings listed anymore, I wonder if they're finally transitioning back to investment cast turbine housings from the sand cast ones.

[Payam@BMS]

I wouldn't want more piping and headache. I would love the fact the BPV is intergrated into it pretty much like the stock car is. It would probably be easier to tune the EFR because of that and the internal wastegate.

[bmw335iguy]

I wish you the best with your ST project! Is your car MT or AT? If its an AT good luck...

[rudypoochris]

Are you sure you want to shoot for 900hp? It was 800hp a second ago. Not to rain on your parade, you are biting off A LOT going for such a large turbo. Even with a quick spool, your spool is going to be horrible at over 300hp/liter. Horrible as in, you won't even hit full boost until 5k or so. Considering we don't have any options for cams/valvetrain, you are really just mismatching the motor in my opinion (you won't be able to use nearly any of the power you gained over going something a bit smaller). You should see if you can drive a similar car first. I highly recommend it.

[benzy89]

Are you sure you want to shoot for 900hp? It was 800hp a second ago. Not to rain on your parade, you are biting off A LOT going for such a large turbo. Even with a quick spool, your spool is going to be horrible at over 300hp/liter. Horrible as in, you won't even hit full boost until 5k or so. Considering we don't have any options for cams/valvetrain, you are really just mismatching the motor in my opinion (you won't be able to use nearly any of the power you gained over going something a bit smaller). You should see if you can drive a similar car first. I highly recommend it.

+1, this is quickly turning into a built motor project (which hasn't been done yet) & the tuning for the current single turbos (Vishnu, CB Performance, garage projects) haven't been "solved" on the stock motor. If the OP doesn't mind being a guinea pig, finding out what the stock limits of the N54 is & burning his bank account, I say go for it.