I ordered my new turbo for my winter project im working on heres what I got. TO4B with 60-1 compressor and 0.84 divided turbine housing with the big shaft option and a polished compressor housing. The guy from Turbonetics said the compressor will support 550hp at 1 bar and the turbine will support 700hp. He said this is probally my best bet for streetable hp and still be able to run good numbers at the track, whatcha think?

 

nice turbo! need a manifold?

 

HaHaHa! You do have a really nice manifold for sale and wouldn't mind having it but I already have mine in the process, mine should cost me about $100 to make out of SS. Im trying to fab everything myself to save some money. I already have spent a **** load of money so I need to save where possible. Thanks though.

 

great idea, but shhhh dont let too many people hear you, they might get ideas

 

OK, I am certainly no expert, but I can't see how an exhaust housing with a A/R of 0.84 can support 700hp on a rotary. Maybe it can on a piston car or something but I think a rotary wouldn't even be close. Not that that number realy means much anyway.
I would tend to go for something a bit bigger, around a 0.9 or 1.0 on a car that is mainly driven on the street. I am pretty sure that a 0.84 exhaust housing is smaller than a standard series 5 exhaust housing.

They are just my thoughts. Anyone else agree or disagree?

 

I had that same thought myself, I was just quoting what the tech from Turbonetics had told me. I was going to go with a bigger exhaust housing but was erged to go with the 0.84 housing because of the quick spool-up I will get, without harming the hp goal I want to reach.

 

I know of many rotaries that are making over 680rwhp without nos running .81 and .84 turbine housings!
Anything is possible. It's the whole combination that matters not just one single part!
The reason the guy from Turbonetics said that was because he sells turbos too many of these guys.

crispeed
87TII
9.20@150mph

 

Well that puts me back to square one when it comes to my knowledge of turbo sizing.
These turbos that are supporting 680RWHP+ do they have a very large compressor and a very large wastegate? From everything that I have read on these forums I wouldn't think that a turbine housing of that size would flow that much gas, but if a large wasegate was used then all the excess gas could go down it.
If a small exhaust housing can support so much hp why do so many people have much larger ones?

Sorry for asking so many questions but this has really confused me.

 

Hey RX7SV: You also have to take in consideration the turbine wheel not only the housing. An O-trim in a .84 housing is completely different then a Q-trim in a .84 housing.

 

I don't care what turbonetics say, the facts are if the engine exhaust side is restricted then this will cause too much back pressure on the engine...in a turbo's case the pressure differential between the intake and exhaust will be an abortion.

When you run the system sized correctly you will end up with a positive intake pressure ratio around 20% higher than in the exhaust manifold. How you do this is up to you (ie large well designed by pass "wastegate" or a large a/r housing) THE OTHER IMPORTANT THING is that the housing a/r in conjunction with manifold length tunning affects where your peak power happens and WILL affect your torque characteristics.

I believe in large style rear a/r's ...but I do not have a torque peak in the below 7000rpm range (with street port) THIS IS THE DIFFERENCE

How much HP you have and where and how you make it and with what boost pressure and what spec engine it is mated too are ALL different issues.

Needless to say no matter what anyone else may tell you the engine with the least intake/exhaust pressure difference will result in the MOST power for any given boost pressure and will be kinder on the turbo not to mention the engine as well.

A case in point is most of the BP runners on this forum have torque peaks around the 6500rpm range, my PP turbo has a torque peak at 9000rpm....different strokes for different folks

 

Also get the frame size right, a 0.81 a/r in a t04 frame size will not support 680rwhp....unless of cousre there is some extreme wastegate setup.

However in the t045 size family this is a much larger housing and cannot be compared to a t04 family housing.

The housing I am using on the PP is a 1.0 but it is large cause it is a different familiy of turbo even though it is called a t04/5....as enzo250 said there are lots of other factors as well such as wheel trims.

 

Quick question for you Rice Racing.

Dou you even need a wastegate on your setup for the FB? I think I remeber you saying you get peak torque in the 7200K range and rev it to 8500 sometimes. Seems to me there would be almost none if any exhaust to bleed off with your set up.

I know I'm probably wrong but I was thinking about this on my way home from work so I figured I'd ask

Cam

 

Yeah I still need the gate, the gate actually starts to work around 6000 rpm at which point I have around 90% of whatever boost setting I am using.

If I only reved it to 6000rpm I would need no wastegate, your method of thinking is pretty right

 

Kinda sound like my last dyno run posted here!
The only thing was that at 6500 to redline the boost pressure dropped by 5psi! You think that would have made a difference?
How about the torque curve being almost flat from about 6000 to about 8800 rpm only varying by 20 ft-lbs and the power from 6800 to 9300 also not varying by more than 20 hp!
I know for a fact you have not seen that dyno run on this forum!
There ain't notting like high power and high RPM's!
Drop the clutch at 9400 rpm and shift at 9500 rpm and cross the traps at 9000 rpm plus in high gear at 150mph! Can't wait for this weekend!

crispeed
87TII
9.20@150mph

 

Anything is possible with the right combination!
A lot of people make claims with no hard facts to back it up. Most people just go by word of mouth or just try to duplicate what they read or saw and think it works. Everyone can use a different combination of parts and acheive the same gold. The secret is to know the right combination.
I have to agree with Peter's(Riceracing) point!
You have to strike the right ballance between intake and exhaust pressure to make power efficently!
The people I was speaking about that run the small housings are some of the top 1/4mile racers in this part of the world. That's the combination that work for them in their situation. You have to decide what works for you. This is their point to the matter. They are getting the same and even better results than the people who are running with the larger housings. Most of the times the people with the bigger housings have to run with NOS to match the performance that they are getting without. That's their view and point as a dragracer.
A road racer would have a different point so will the average street racer or user.
Basically it all boils down to what you want and is satisfied with.

just my opinion.

crispeed
87TII
9.20@150mph