Power/turbo question
 

I know this has been covered numerous times, but, everyones mods are different, so...........

I have an S4 Jspec, Walbro, Microtech lt8, 720 sec's, MBC, stock top mount, K&N, 3" single turbo back. What's the most power I could get to the wheels fairly safely with this setup on stock turbo? Also, what turbo would be reccmended for between 300-330 rwhp at abo0ut 15 p.s.i.? And if it's reccomended I go for a whole aftermarket turbo instead of a hybrid, what would I need to install it? i.e. manifold/wastegate, etc...

And, as far as tech. aspects of turbos goes. I don't understand the whole A/R, trim, etc... What's the diff. between a t04b/e/s etc...? Any and all info would be awesome. Thanks.

Stock 4 x 550's good for 240hp at the wheels safely.
Increase of fuel capacity from 550 to 720 is +31%.
Upgrade to 2 x 720's in secondaries only in secondaries is +15.5% in fuel capacity.
Thus, 240hp +15.5% = ~275hp at the wheels.
The Walbro will tend to bump up the fuel rail pressure, so this number will get close to 300hp at the wheels.


-Ted

Thanks Ted, youre a wealth of info and an asset to the entire community. Does anyone else have any more info on what I should get/do?

Answers for the rest of your questions...

A T04B H-trim will be right at the edge to make those numbers.
The next size up is a 60-1, TS04, or T04E "60".

This depends on your budget.
The full turbo + aftermarket turbo exhaust manifold + external wastegate is superior in flow and power output, but it costs a lot more money.
The hybrid of compressor upgrade option is very economical, and allows you to keep the stock turbo exhaust manifold, downpipe, and oil and coolant lines.


In general, the T04B is an older design.
The T04E is a newer design.
The T04B has the older 2.5"(?) inlet, and the T04E has the larger 4" inlet - this really doesn't matter, but people jizz about the inlet opening for some odd reason. :)
If the "T04S" you're talking is is a Garrett T04S04 or TS04 (for short), it's basically the same as a 60-1 or T04E "60".
All three turbos make about the same amount of power.

Ignore "compressor A/R".
Turbine A/R dictates power band (where the boost hits), and as a rule, try to stay around 1.00 A/R.


-Ted

So, say I wanted to go hybrid to get to about 300. What would I upgrade the compressor side to? It's going to stay stock port, I don't know if that makes a difference. Thanks for the info, again.

Anyone have any suggestions?

www.rx7store.net has the bnr and if you where to get any I would get stage III because they are all so close in price and the stage III give 350rwhp.

H-trim would do 300 at the wheels.
In general, the compressor upgrade will do about 10% to 20% lower power output versus a full turbo upgrade.
So while a full H-trim turbo would do about 350 at the wheels, the H-trim compressor upgrade will do about 300hp at the wheels.
The next size up is the 60-1.


-Ted

Just want make it more specific...

T04B compressor housing:
2.75" inlet only

T04E compressor housings:
2.75", 3", 4" inlets available

T04S compressor housing:
4" inlet

Most people know the "T04S turbo" to be a "T04B 60-1 turbo". In other words, they are the exact same things. Keep in mind, the wheels have different designs between the T04B and T04E. However, the 60-1 wheel (the wheel in the "T04S turbo") is more similar in design to the T04E wheels.

A TS04 and a T04E 60-trim are different turbo's from the T04B 60-1 and from themselves. I agree that the TS04 and T04B 60-1 should make roughly the same amount of power @ 15psi on our motors, but the T04E 60-trim will need around 20psi to make near the same amount of power. This can be a big enough difference that it will require switching from pump gas levels to race gas.

As for the hybrid thing, I would go with either a T04B V-trim wheel with a T04B compressor housing or a T04E 50-trim wheel with a T04B compressor housing. Both should meet your goals of 300rwhp @ 15psi on a stock-port motor. If you go with a bigger compressor wheel, I would suggest at the very least, clipping the turbine wheel as well.

Thanks for all the awesome information guys. I'm thinking about going with either the BNR stage 2 or 3 hybrids. It's just not worth it for me right now tp soend thousdands on a full turbo upgrade as opposed to 800 for a hybrid, fmic, and injectors. So, either one of those are on my wish list. Again, thanks for the info.