hey guys, its almost time for a turbo rebuild, everyone was saying i should have had them done when I remanned the engine but I was strapped for cash and holding out for something better. That something, i eblieve, it a GT35r kit. I love the feel of my FD and how quick the seq. twins spool up but I want more power than they can provide for me. My goal is above 400whp on pump gas. My question is, do you guys think the GT35r is capable of producing such numbers?

 

YES! T4 1.0 will offer great reponse and allow for better flow up top.

 

That's gonna be my turbo upgrade also, except I'm going to rebuild with 9.7 compression rotors to further improve low-end and drive-ability. That combination should make up for the loss of my seq set-up down low.

 

i did the high comp's with a t3 gt35r. spooled great, but egt's were crazy up top, so i held it back to ~375whp.

 

Dave, just wondering, why'd you go with a T3 setup? What was the A/R of the housing?

 

[ My goal is above 400whp on pump gas. My question is, do you guys think the GT35r is capable of producing such numbers?[/QUOTE]

Yup you can, Spool up is great as well. I dynoed 407rhp with a small hot side (ATP T4 .82).....

 

What is the spool up like with that .82 hotside? I'm looking at going with the same A/R on mine, but I wasn't sure if it would be too small or not. Also, what boost did you hit 407whp at? Thanks in advance.

Zach

 

Spool up is great....full boost by 3600 rpm, 407 was at 15psi. I tracked( road race) the car at 10psi and it was flawless.....

 

I don't think you can go wrong with that setup.

As an alternative, I recommend you also look at BNR Stage 3s set up sequentially. The response and low end spool is identical to stock, and you'll be able to make your 400 rwhp goal on pump gas.

http://www.bnrturbos.com/3rdGen.htm

 

a/r was 1.06
because only a handful of places have the t4 turbine housing. most of them don't have an a/r large enough, one has it, but it's basically a t3 hotside with a t4 flange re-casted, and the last pace was about $400 more for the turbo and they acted like dicks when i asked if they sold just the turbine housing.

 

At what boost were you getting that power? Also, at what rpm did you hit that boost?

 

actual hp was like 373 @ 12.1 psi. i was trying for 10psi and ~350 whp, but it crept up to 12. torque was nice and flat, but just angled upward a bit. 10psi came right after 3krpm with shitty boost control. i had 4psi at like 2200rpm, though.

 

I have an A-spec T4 (divided) GT35R w/ 1.06 hot side...street ported by Rotary Performance...everything to support it.

Power? Spool up?

I will let you know in about 2 weeks after it is tuned and dynoed. I am building it for a road race application.

 

DOH! I was so sure I was getting the GT35R, I was positive it was the way to go, nothing could sway me, but now......... I find out their is a possibilty to reach my goal on twins and keep the low end spool

Now its a decision. Lets see, factors I can include are

1. Price
2. Engine space
3. Spool Up.
4. Max potential
5. Installation difficulty.

As for price, I think the BNRs are cheaper with my core and y pipe, Engine space I think the GT35 takes it there but im not sure, spool up is what the twins are known for, Max potential ?? (No Idea), Installation difficulty? (No idea either)

Thanks for the input so far guys, what d'ya think?

 

6. efficiency
7. simplicity


-S-

 

As much as I like the BNR's, I am on ZeroR's side here. For overall reliability, simplicity, and efficiency a single will always be the way to go.

Zach

 

8. uniqueness .

on a serious note, I will not argue #7, a single will clear out your engine bay quite a bit vs any seq twin setup.

Efficiency, not really sure what to say. I run 16-17 psi regularly on the street and my intake/engine temps are always rock solid.

Regarding spool up, the seq BNRs will kill the 35r, hands down.

max potential is similar on pump gas, on race the 35r will make probably get you closer to 500. I haven't pushed to the edge of the envelope with my current setup so not sure how high it will get me, definitely not much past 450.

install difficulty, any single wins that one.

As far as driveability, do you want great boost at 3000 rpm or at 3500 rpm? Imagine how a modded stock twin car drives, then add 20% (the BNRs are a full 20% larger than the stock rotating assys). Of course, the single will give a more linear power delivery than a seq setup. It's all a big give and take

 

dude get some traps for that thing. fyi... i will be at etown on sunday with my buddies.

 

You have a very understanding wife, lol.

I have been spending most weekends wrenching on either the vert or the FD. It's time for me to spend some quality time with the girlie

 

I was refering to effiency as a whole unit. I'm sure the BNR's are efficient on the compressor but the exhaust manifold is killing them. And replacing parts on that manifold get harder every day. I'm glad to see your having good experiences from them though.


-S-

 

I have the A-spec T4 flange 1.05 hotside GT35R kit. I just did my first rough in pass on the load map for my Microtech. With conservative timing and 11.5:1 or worse AFR I pulled 459 at the rear wheels at 18 lbs boost. This is going to be a road course race car, so I am swapping a lower pressure spring into the wastegate and increasing the size of the wastegate signal line. My master plan is to try for 350-375 hp at the wheels at a very trackable 7-10 lbs boost. It is nice to know that if I want I can dial it up and make some big numbers though.

-Trent

 

Nice! How do you like the response of the larger turbine housing?

-S-

 

I would like to know this as well.

Sean,
What sort of turbine housing would you recommend for your 500R. I have the 35/40 w/ the 1.06...I was just trying to think ahead. You did say one of your 35/40 kits could be upgraded to the 500R correct? or am I mistaken...