i'm looking into these two turbos by Garrett, the GT35R and the GT40R. both are Ball Berring turbos and from the maps it looks as though the 40 has the exact same spool time but with higher flow than the 35... am I looking at these graphs wrong?

I created these overlays to show my point. the comp map displays the 40 in blue and the 35 in red. the boost graph displays the 40 on the top 4 lines and the 35 on the bottom 3.

my question is would the 35 create positive pressure before the 40 with a 0.86 A/R???

My goal is only about 350whp from an S4 engine. (with supporting mods of course) but I want it to spool as fast as possible to reduce lag without the risk of choking the engine at all if any up top.

thank you for your help,
TR

 

thats too much of a turbo if you're only looking for 350whp

 

I really have alot to learn about the turbo upgrade i want to do.

thank you,
TR

 

fwiw, if you're looking for 350whp, i'd go with a t04b or e 50trim or 54 trim. you can make 350whp on pumpgas with that without much fuss.

 

If you are looking at a T04E than I would look at nothing smaller than a 57-trim . A 50-trim is too small for a rotary.

 

he has stock ports and he only wants 350whp max.

i have a v1/v2 (which is close to a 50trim) t04b and i made 330whp@13psi. the 50 trim wheel and bigger E housing should be plenty for 350whp.

however, yes, a 57 trim would get to 350whp more easily.

 

You have to add a bit more info.Your dyno was on a street ported motor with a large 1.15a/r hotside,correct?

 

Go bigger than you plan. If you think you want 350rwhp, you're going to get used to it, and want 400rwhp. IMOP, 400rwhp for a street car is very nice. CJ

 

yea exactly wwhy i am going with a gt42r, i plan on 450-500, but you never know, if c16 falls in my hands> turn it up to 550-650

 

ok so the general concesus from multiple people I have been talking to is T04 e 57-60 trim with .84-1.00 A/R... what the hell is A/R? the only thing i know it as is the radius from the turbine shaft to the housing wall... so it would dictate the physical size of the turbo.

thank you all for taking the time to confirm everything, and helping a SEVERE turbo NOOB out.

a fine point: again I'm not looking for a turbo to kick me in the @$$ at 5,000rpm a want the turbo to start generating posative boost as early in the rev band as possible with making the 350WHP i want on stock ports and minimal if any chocking of the engine up top... no detrimental back pressure.

thank you all again,
TR

 

If you want early early boost response then you don't want a GT40R. There are versions of the GT35R now that will give you really early spool up with great power potential. You could also use the standard T3 hotsided GT35R and easily hit the numbers you want. Or you could look into the Apex'i RX-6 turbo. That spools up very fast and shouldn't have any problems hitting 350rwhp. If you weren't as worried about spool then I would say go with a regular 60-1. That would easily hit the power numbers you want, but I don't have enough experience with them to tell you the spool characteristics of it. Good luck to you.

Zach

 

I agree with a lot of the comments made in here including the solid answer made by Zach other than the 60-1 part (which he DID say he wasn't that familiar with it).

The nice thing about the 60-1 is that it is relatively inexpensive, has a T4 flange which will mate directly to the also inexpensive HKS cast manifold and will provide you with the power you're looking for. I ran mine with a 1.15 hotside on a stock ported motor and I loved it.

If you want a faster spool and still be able to hit your power goal, go with the .96 hotside. I would say the .84 for even faster response, but I'm honestly not sure if that would curb you just shy of your 350whp.

IMO, for the money, that's the way to go. If, however, you decide to go with the ball bearing turbo, the GT35 is a great choice. I'm not intimately familiar with it but I know of a good number of people who have had great success with it.

My $.02

Reese

 

Go with the 35r with the T4 flange, even with the stock ports. Then when you port that a little bit you'll be into the 400's. Aspec RS based 35 would be better on a ported engine I would think.

Don't do the 40r on a stock ported engine with low boost or HP goals.

 

 

My mistake on that point. I didn't realise the 35 could be had with a T4 flange. If cost isn't the issue, that would be a good choice.

 

Reese, I've told you about that T4 GT35 variant before. You don't listen!! I would have to say that if you have the money that turbo seems to be the one to beat these days!!

 

Do you have a refrence to purchase this T4 turbine housing for a GT35R bb turbo? I asked Innovative, but they don't have any idea where to get a T4 housing for a GT35R. I have a T3 and would like to have the option to bump the housing up bigger.

 

www.atpturbo.com

 

I just bought a GT4067, not an r, it has a 67mm inducer at compressor housing, 4" inlet .58 A/R,,,,,, turbine housing T4 flange .95 A/R, but the exducer size measures as a Q wheel, I would have preferred a P wheel turbine, what might be expected from this turbo. its brand new never used. and finding P trim wheels and housings for GT40s aint easy, and probably cost more than another turbo. looking for 500whp FD. any opinions??

 

pushing this back to the top.

 

why?

 

want to know if anyone knows anything about the precision gt4067.