what turbo? (450hp MAX, quick spool?)
 

Im changing the turbo in my FC drift car, looking for somthing a little more responsive at lower rpms. I currently have an Innovative GT70 BB turbo on a cosmo motor with a big street port, haltech e6k, 550cc primary, 1600cc secondary injectors... It made 410hp @ 13-14psi ( on a dynapack dyno). im looking for a turbo with max hp capabilities of about 450, and most efficient at about 380-400hp (where i usualy run the car). I know ill have to run more boost to make the same power with a smaller turbo, but i dont want to run more than 18psi... Any help would be appriciated. heres a link to my almost new GT70bb turbo for sale.

https://www.rx7club.com/showthread.p...=1#post5979093

Theres a few turbos that can offer that. I believe the best one would be Aspecs GT35RS from what I have read.

Yes, the A-Spec 500R kit will suit your needs just fine. It made 436rwhp at 14psi or so on a mild streetport FD so it will make the numbers you want all day on your motor. And it also spooled extremely early. That is the kit I would choose because you'll get a great product, a lifetime warranty on the manifold and DP, and some of the best customer service in the business. Just my .02 from my experiences with A-Spec tuning.

Zach

Thanks for the info guys! I dont need a whole kit though, i have a manifold, wastegate, and downpipe already (custom made). So all i need is a turbo by itself... Do you know if a-spec sells the turbo alone?

You always look into a dual bb PT63.....I don't think the aspec guys will sell that turbo seperately.

I sponser one of the local drifters here in NZ, Jt from Drift corp. hes new car for next season is an Fd 13b we will be running mp gt37 with .84 or even .7 ar housing and the new 70 trim mp gt turbine, which is slightly smaller than the conventional p trim. this combos should make massive responce and should still have enough increased exhaust flow over stock to not restrick power levels of the gt37 compressor.

He has driven one of the apex d1 fd rx7 from japan. its still here in NZ in storage until next event. But basicaly he claims there car make full boost at 2500 rpm, and this is what he want to achieve with his turbo combo.

id recomend you consider this as an option also.

I can't sell the 500R alone I have too high a demand for the kits, and I wont short change kit sales. I can get you 35RT4's and that would meet your goals in power and response.

HOw come you can't sell the turbo by itself? Couldn't you just get a couple of them build to sell? I'm looking for that turbo, but I already got the manifold, downpipe and wastegate and i just need the turbo.

I can't keep up with my kit orders on it as it is. 450HP MAX with quick spool a 35RT4 will do it. Also for cheaper than it costs me to make a 500R.

-S-

Thanks for the info bobybeach & Zero R. How do you think a .70 or .84 housing would work on the turbo i already have? would the compressor size difference be too much, or out of efficency range too far to work properly? I know the small exhaust housing would not be high rpm friendly, but since its for a drift car, the low to mid range response is far more important than if the power falls off at 7500rpm... Thanks!

Really nice response, I would go no smaller than a .84 divided on a divided manifold. Turbine A/r will not effect compressor efficiency and I bet you will be more than satisfied anything smaller will just hurt you.

-S-

a plain ol gt35r will get you there no problem

hurt him how? power falling off at 6.5k? 400hp at 16psi comapired to 400 @ 13psi?

explain a little more please if ya dont mind.

the smaller housing wont kill top end power. as long as your compressor is large enough to hold solid boost high in the rev you will still continue to make power in the high rpm
. the smaller housing will kill some torque all through the rev range but will make peek torque earlier than the larger housings. And if you have enough compressor flow you can just up the boost to compinsate any loss in power by going smaller housings.

Sorry that I didn't remember to mention you in this thread Oliver. I haven't seen you on the boards in quite some time and it totally slipped my mind. My apologies.

Zach

He is not going to be running a 70mm turbo, he wants to run something smaller. Going smaller then putting on the smaller turbine to boot is not going work. Find me a 35R sized turbo making 400whp on a .7x turbine A/r while doing it under the 18psi limit he is asking for. I don't see it happening. Running a split pulse .84 will give him quicker respnse than your standard .8x and still give enough room to hit the 400whp mark. 450 is another story. We run 35RT4's split pulse 1.0 and get about 440whp at about 14lbs. On street ported motors. This setup will get 1 bar by 3300-3400rpm. I see no reason to go any smaller than a .84 SP for his goals. No need for the higher back pressure when he can do it without.

-S-

I'm curious to see what one of your turbos will do with a .84 divided housing on it versus the 1.0 Sean. Anyone running one of those yet?

Zach

Not with the .84 no. I'm sure it would be a very fun car though.

-S-

actually he is thinking about keeping the 70mm turbo... thats why i asked the questions i did. The reason I care is because i also have a 70mm turbo.

There is someone on this board running a .70 on a t66 with great results. Im going to search and figure out who it is and ask him to chime in.

I was thinking about it, how the only reason to run a bigger housing (1.0 +) is to eliminate pre turbine back pressure so the engine can breathe freely at higher rpms... Heres my thought, if you run a .70 housing, the turbo will spool up very quickly, but then choke the top end. but if you have a large enough wastegate or 2 wastegates, bled into the atmosphere, that also is reliveing back pressure. I think the only time this wont work well is if you have a smaller turbo that maxes out its flow, by spinning the turbine too fast and stalls the compressor wheel, or just makes more heat. Are my thoughts correct, or am i missing somthing? My logic is that if you have 100 cfm that needs to be expelled from the engine, and your turbine/ housing can only flow 75 cfm (with reasonably low back pressure), and your wastegate/s can flow 60 cfm, then you can expell all your exhaust, and have room to adj. your boost via the wastegate/s... Any thoughts?

Thinking more about it, maybe it takes x amount of back pressure to operate different turbine housings, and the smaller one makes more back pressure to operate regardless of how much exhaust you displace with the wastegates...? Anyone?

yea something like that. there are lots of threads with people asking if they can just add another WG or get rid of that backpressure. The replys are always someting about like what you just wrote.

if the WG could relieve enough of the pressure it wouldnt make boost up top anymore.

It doesn't quite work that way, if you could bleed off more as you say, it would be pre-turbine, so all you would be doing is limiting your boost level by limiting energy transfered to the turbine. Not to mention running larger wastegates can add lag by being slower to respond, as well as more oscillations on power delivery. Smaller wastegates with stiffer springs will have a sharper boost rise and crisper response. You will need to be careful though, on how you control boost pressure.

-S-