only good answer in here and is the correct one from back to back swaps I have done. not really any point in arguing rpm spool. If someone has a 37r that spools at 4700 rpm, that same setup would spool 35r at 4000. I have aem log of my 35r hitting 26psi at 4000rpm. from my test rides of many cars the 2.0/35r hits full boost at 5100 and the 2.0/37r hits full boost at 5800.

 

no one seems to be considering gear selection either. obviously its gonna hit full boost earlier in 5th then 3rd so I think everyone should be considering that

 

Please post this log that you have. Also what gear and was this on a dyno or street? Thanks.

I agree and along with that, please post what your "full boost" numbers are. Full boost means something different to everyone whether you're running 20psi on pump or 30psi+ on race gas. It also helps if you're getting these numbers from a MAP sensor log.

 

Not being an ***, I just like facts, sorry if you got offended. The truth of the matter is that I have never seen any type of log or Graph that says a person hits full boost from 4500-4700rpms. Its either one or the other never a range, with that being said it looks like speculation to me. This would mean that there is no graph at all to support this claim. We like facts not what people think,assume,estimate, or speculate. As a newbie or someone just getting into modding for the first time and we all have been there. I would like the most accurate info when spending this type of money on anything.

So when you post, please post facts that can be either backed up or that are believable.

Thanks,
Migsubishi

 

And for those who may find it interesting . . .

I had:

GT35R, 0.63 A/R T3 turbine housing


I went to:

PT67R, 0.70 A/R T4 divided turbine housing


The PT67R with the much larger, divided T4 housing spools quicker than the GT35R, and feels much more responsive. There are ways to have one's cake and eat it too . . .

 

Ted B, I would suppose then if one were to take a GT35r with a similar divided housing / twinscroll, they would make a little less power than you, but spool even earlier...

 

Where did you purchase this turno housing and can you pm me a graph supporting this claim. The only reason I left the 67mm is because of spool. What a/r is the housing?

 

It says .70, you can get the divided housings from ATP for the 35/30R series,and you can get the T4 divided housings from most places.

Scorke

 

That would be a logical assumption, but I don't know about the availability of a true T4, divided for a GT35R. Someone may want to comment on this. I think what I've seen look more like 1.06 A/R T3 housings with a T4 flange or something unusual. I'm sure Geoff knows more about GT35R possibilities.


Scorke answered part of the question. As to the graph, I haven't digitized it. We were having other issues, so I didn't bother. Rest assured that the dyno doesn't show just how much of a difference there is between a T3 and divided T4 at ALL throttle positions and rpm. The T3 feels dead. The divided T4 feels like it always wants to GO.

In fact, it works soooo well, that I am contemplating going a bit larger on the turbine side . . .

 

Ted, do you feel that going larger on the turbine side is easier because your now running twin scroll, and how do you expect that to effect the shape of your curve vs going with a larger compressor wheel?

Is the only real downside to the larger compressor the increased mass/inertia of the wheel, if not what else? I just feel that a larger turbine will kill some of what you gained over the 35R setup, no doubt with a lot more top end..

Can you stuff a 67mm wheel on/in a 35R compressor housing/center section? If not do you know anybody that does anything like that?

I remember Walker's buddy that lives in SC near me in Clemson (twinturbo240z) is his tag telling me about the Big Kahuna's they used to run, which I think was something similar to what I am asking about?

Scorke

 

I'm not sold just yet on the larger turbine side. I am only contemplating it, given the nature of the engine configuration that is going into the car in the next few weeks. Rest assured I'm not anxious to give up any response unless our pressure testing indicates we're likely to gain more than we give.

 

anyone with turbo knowlege will recomend a G35 all day long. best bang for the buck and quicker spool up about 300-500 rpm quiker than a 37

 

never had a 35r on the car but i can say my turbo is a pt67r with a .82 hotside. My block is a built 2.0 I am going to switch to a 2.1 soon. I start spool at about 4200 and hit full boost in between 5500-6000. It is a smooth powerband so the lag isnt annoying to me at all. I have been dd it these past couple of weeks and it works out fine. Hope this info helps.

PJ

 

subscribes.

 

That appears to be about right.

FWIW, to make a comparison with the very same turbo using a .70 A/R divided T4 hotside, full boost (25 psi on 93 oct) comes about 1000rpm quicker.