Hi all,

Have been looking through the threads and am seeing the pros and cons of each of these turbos and on paper they seem to make similar power. What i cant find is where the power comes on with these and where it drops off.

So what i am trying to decide is which would you all prefer given the choice?

Also on a side note for either of these turbos would you recommend the Tial 44mm or 46mm wastegate

This is going to be for a street car which i plan on running in the low 11 second quater mile

Here are the specs of the two turbos i am trying to decide on which would you choose and why?

t61mm .7ar p trim 1.00ar
GT35/40 .7 ar 1.06 ar

Look forward to your thoughts

 

That GT35/40 has a smaller exhaust housing (it's close to a T3 size, whereas the T61 you have listed has a T4 exhaust housing). With that hotside, the GT35/40 can make 15psi at about 3500 rpm. The T61 with a 1.00A/R housing will take until about 4300rpm to hit 15psi.

You should be able to make more power with the T61. I don't think it's necessary to spend the extra cash on the 46mm gate - the 44 should be fine.

 

I have a GT3540R and love it. I have been in a car with a T61 and it was nice too. The extra 1000 or so RPM of power is really nice if you do anything other than drag racing/highway racing with your car. I have over 400rwhp and serious power from 3500rpms to 8500 rpms. The GT3540R feels almost like stock twins if they actually had some nuts.

The T61 "feels" faster though because when the power kicks in it slams you back in your seat. The power delivery on the GT3540R feels very linear.

I guess it is all about what you are going to use the car for. If it is going to be auto-X, road course, moutain runs, etc. then I would go with the GT3540R. On a street port motor you will be "stuck" in the 400-430whp range with the GT3540R turbo. If you are going for more high end power for drag racing/highway racing then the T61 might be a better choice being that you can get an additional 10-15whp.

Low 11s are a snap on either turbo. You problem will be traction not power.

 

Porting helps low end *AND* early spool up, right?

How the hell does that work? And, is the off-boost responce changed or hurt?

 

I have never had the turbo with out the porting. I see positive manifold pressure very fast and my off boost response is super fast. If I tap the accelerator it hits boost. I can do a typical auto-X course in 2nd gear and it is fairly easy to keep the turbo spooled the entire time.

 

GT35R=GT35/40 is a very fun turbo with great useable power, very fast spool-up and minimal lag.

 

855m0no:

Where did this "STUCK" in the 400-430 range come from on a gt35r. I made that power with stock ports on a gt35 at 15psi. So your telling me that I wont make anymore power once I street port. hmmm... not sure about that.... GT35r is good for 500rwhp.. thing is that no one here runs more than 20psi... the gt35r dosnt feel alive until after 15psi...

 

I was being facetious. 400-430 whp at 15-16psi is a lot of power. I am sure that someone could get 500whp running lots of boost. I am to chicken to run more than 16psi. I am sure that the turbo is insane at 18+psi but I don’t think I will ever know. I only dynoed this setup once and I was having major fuel issues. I put down 370whp at 11psi at 6000rpms. I started running lean so I stopped the tuning effort until the fuel issue could be fixed. I keep meaning to go back to the dyno and see what I am putting down now. I conservativly guess it is in the 420-430whp range being that I have seen many other GT3540R setups in that range with 15 or so psi of boost.

 

Just so there’s no confusion, the T61 is NOT the same as a 60-1 (aka: T04S, T60-1, T04B 60-1 etc). The 60-1 runs off its most efficient map island after approx 45 lbs. per min. at around 2 bar (15~17 psi) were the T61 (T-series big shaft T4) can flow over 50 lbs. per min. at 3 bar. These two turbos are very different.

The 60-1 and GT35R compressors are a closer comparison and people get similar results between the two. The GT35R does flow slightly less then the 60-1, but is more efficient at higher pressure ratios.

~Mike................

 

And now that we can get a GT35R with a T4 hotside, there really shouldn't be much of a comparison at all. But then again, that's just my viewpoint.

Zach

 

Better, but not "ideal". Check out the turbine efficiencies- The T61 wins. Having said that, I like the hell out of my 35R.

Gene

 

i have a t61 with a 1.0 exhaust side. so just about exactly the same turbo your talking about.

The lag is pretty heafty IMO, and i have a ported motor. I have never been in any other single turbo fd though so i have no basis for compairison.

Mine is setup running between 16-17 psi and soon as the boost peaks it continues to pull like crazy until I shift.

on a street ported motor with 12 psi this turbo put down 356rwhp on my car.

 

fast spoolup AND minimal lag? cool!

 

Sorry bud but 2 bar does not equal approx 15-17 psi. 1 bar=14.7 psi, 2 bar = (14.7X2). Just wanted to clarify that...... :-)

 

There's no way in hell a GT35R will ever see 500rwhp. Maybe if you overspin it and overheat it at some 30psi and two weeks later the oil seals puke on ya.

Its a TINY, PUNY, EEENNY, WEENNIEE, turbo! Reason nobody runs more boost is because it falls out of its efficiancy range. Same reason nobody runs more than 15psi on stock twins. 20psi would be the max on the GT35R as far as "good" power is concerned, but you are right, there probably isn't a better "street" turbo.

 

He was probably speaking in terms of ABSOLUTE pressure, not RELATIVE pressure. If not, yes, he mistyped.

 

You mean to tell me 400-430 WHEEL horsepower is teeny puny eeny weenniee? You really must be more insane than I am, especially considering how light a RX-7 is LOL. You, sir, are a god among men.

 

I believe that 15psi on the GT35R is about the maximum you can squeeze out of it using 93-octane pump gas.

 

Originally Posted by diesel power
Sorry bud but 2 bar does not equal approx 15-17 psi. 1 bar=14.7 psi, 2 bar = (14.7X2). Just wanted to clarify that...... :-)


Sorry for not clarifying, but as rynberg said, I was reffering to absolute as what is shown on compressor maps (presure ratio, inlet verses disscharge).

FWIW, I still think some people are confusing their 60-1 with the T61.


~Mike............

 

mine is def a t61, see you can kinda read it written on the compressor housing

"no surge t61"

 

Def a T61, it has 6 paired impellers and whats the "no surge" mean? Usually anti-surge housings have a ported shroud, yours is a standard Garrett T04S comp housing (used on most medium/large compressors).

~Mike.............

 

What's the difference between a 60-1 vs T61?

Is the T61 that much larger?

 

my shop ordered the turbo for a wrx 2.5l project car. The wrx had a gt35r on it before that kept surging, so this turbo was the solution to the surging problem. the turbo builder (agpturbo) thought it would be cute to sharpie a happy face and no surge t61 on it :P

we ended up changing out the cams and i think went with a different turbo too, I was planning on getting a t61 anyways but this one was on the shelf so I just swapped the exhaust housing and used it on my setup

 

The difference is these are two totally different compressors.

60-1:
Inducer: 2.324"
Exducer: 3.000"

T-61:
Inducer: 2.382"
Exducer: 3.544"



I tried pasting the comp maps, I dunno if they'll appear {edit, no they didn't}. If they don't just look them up and see the differences in their maps, quite different.

Looking at the two, the 60-1 has 7 paired impellers while the T-61 has 6. Also, while the 60-1 can be purchased with the large shaft option, the T-61 comes standard with it. Both come standard with a T04S .7 A/R 4" inlet and 2.5" discharge comp cover.

~Mike.....................

 

exact opposite.