hey been thinking about changing the twin turbos on my bat-was looking at a single turbo but thort may try something a bit different-was looking at two t28 ball bearing turbos off an s15 silvia -maybe if someone with a bit more turbo knowledge could help -would the 13b be able to support these turbos or other way round cheers

 

ive read on doing this.. and aspec lists something like this on there site.. after contacting them a while back they informed me they ditched the project as it was a pain and will be super expensive and wont give you anything extra that a larger single would give except maybe the cool factor of having two turbos..

i like the idea myself but when reality sets in is it really worth it for the hassle and money spent to custom make everything??

 

Check out my build thread in the n.w. section, I'm using gt30's with TiAL stainless housings. Building the manifold currently. Using 2 wastegates and 2 b.o.v.'s. Gt28's are undersized and restrict the exhaust I would think.

 

could you make a manifold that didnt have a wastegate to house two gt 30's etc?? if so I may be intrested in buyin one from you..

 

getting things made up isnt a problem -just wondering if the turbos would flow the exhaust needs of an 13b -i figured they would be a alrite choice considering the s15 had the two litre sr20 -so a pair could run it?

 

twin t 28's should be good...as long as you build the system to work with them.

read and do plenty of reaserch (maximum boost by corky bell, search on google for the pdf or buy it if you like)

I'm actually doing a twin k04 (which are just about the same size just a tad smaller) setup (getting ready to build the manifold) they are the stock turbos on the mazdaspeed 3 and 6 and the cx-7. the advantage of using a turbo with a built in wastegate is that it will simplify your manifold design quite considerably.

someone on the forums a while ago was thinking about marketing a twin gt/t28 manifold design for the fd but i guess it never went through, but you might be able to get some useful information off of the thread just do a search.

also i think that XS Engineering had a rx-7 track car that was a twin gt28 turbo car and it was putting near 700 to the ground. check out their webpage it might still be up on there.

best of luck and keep us posted on your progress.

 

I tried a twin kit a while back.

Looking back, id just go single. But if you are going to do it, keep this in mind:

1. Do internal gates. Make them work.
2. Think about heat in the engine bay. Twin turbos are going to produce ALOT of heat that will try to destroy everything. If you think you can plumb it easily, try to do water cooled chra. Think about your routing for oil lines while you are laying out the manifold and make sure they are protected from heat.
3. FD engine bays are small. When you make your manifold, think about how easy it is to work on. You are stuffing so much crap into a little space, so things will get tight. When I had my manifold made, I didnt stress that point enough. The stock twins are a bitch to work on. You dont need that all over again.
4. Think about what power you want very carefully, and dont get greedy. I sized my turbos way big because i wanted to make a ton of power, but i never really used it. Size your turbos out, talk to distributors, study compressor maps and make a solid choice.

Is this a street car? Go single. honestly, a few people have tried to make twin kits for retail. I dont know if the market just isnt there, but my shot at making a twin kit made me realize that it is just isnt worth the added complexity. I think I could build a much more functional and reliable kit the second time around now that i know what to look for. If you work on your car yourself, its better to keep it simple and reliable if you dont want to be tinkering. if you do, then go for it and have fun.

 

The stock S15 Silvia T28 turbos are pretty responsive.

I remember my friend had pretty good response on his s15 with Tomei Camshafts, Metal Head Gasket, mild head work, Trust Exhaust manifold and Trust Ti-Exhaust with the stock turbo. He put down close to 300 whp on 91 california **** gasoline with a Power FC.

He tried to upgrade the turbo to a slightly larger garrett turbo, but eventually they found out that the stock T28 outflowed the Garrett turbocharger ( i forgot which model/variant it was ), so he went back to stock turbo. The car ran REALLY well on it.

So, if you can make a 2 T28s work together on an FD3S, I think it could work theoretically. Power levels, and response will be good, however, i would imagine there would be a few special parts that would be needed, and a good standalone ECU to control everything.

 

the car already runs a stand alone microtech computer -that was the main decideding factor on t28s they are ball bearing and cheap to buy for me -plus internal gates make easy -anyone be able to tell me a place to look at t28 compressor diagrams to work out if suitable

 

Any shops in your area that modify S15s or Silvia's should have it. The S15 Turbo is a common upgrade for S13 and S14s as well. This information should be available in NZ, Australia or Japan. I know someone in california who would have the information, but i am out of town and cannot ask.