How do I determine what size Turbo I need?

starscream5000

Senior VIP Member
Aug 23, 2006
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Hot and Humid, KY
Ric said:
Why not? Everyone else in the MKIV world does, and they seem to have no problems roasting everything on the road.

Maybe this guys doesn't want to "roast everything on the road" and wants a fun powerband to play with. Waiting until 5K RPM to all of sudden tire roasting torque is no fun. I'd rather have a car making boost at 3-3.5K RPMs with a max power of 500 HP versus a car making the same HP, but with power coming online at 5k RPM anyday of the week.
 

OneJoeZee

Retired Post Whore
Mar 30, 2005
5,721
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aboard the Argama
Ric said:
Why not? Everyone else in the MKIV world does, and they seem to have no problems roasting everything on the road. 3 liter 2JZGTE's with GT4788's are running low 9s all day long without the laughing gas. Even if you have a GT35R, you still won't make power til 4500. Whats another 500rpms to get 100 more whp on pump gas?

If you don't like turbo lag, stop playing with 2.5 and 3 liter motors. Your installing a blitz twin kit thats going to make less WHP and lag worse then my 4088


Responses like this is are exactly why I should remember to not even bother trying to argue with you.

1. Not everyone with a MKIV has a huge turbo. Don't even try to say they do. TONS of people actually took time to choose a turbo that is right for their goals. There are tons of MKIVs with 61mm and 63mm turbos.

2. I'm not even to say anything about your response trying to shift the focus onto me. My car has nothing to do with the topic here.

I'm done this time. (seriously)
 

starscream5000

Senior VIP Member
Aug 23, 2006
6,359
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Hot and Humid, KY
Comparing dick sizes now? :3d_frown:

I'm done here too.

/OT

To the OP, according to the more knowegable people on here with experience on Garrett turbos, you should be good for what you want on a GT35R and it's variants.
 

Blackfin

Beach Bum
Jun 16, 2005
205
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John's Pass, Florida
starscream5000 said:
Comparing dick sizes now? :3d_frown:

I'm done here too.

/OT

To the OP, according to the more knowegable people on here with experience on Garrett turbos, you should be good for what you want on a GT35R and it's variants.

Too funny.

I was just trying to be on the conservative side of things.
 

foreverpsycotic

Back in the game!
Jul 16, 2006
3,171
12
38
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ATL
Ric said:
I was talking about GT4088R comparable to a GT35R. The GT4088R is only 2mm bigger then the 35R. The non BB GT4088 is 1mm bigger then the 4088R.

and? it would land him within his power goal correct? bigger isnt always better.
 

tte

Breaking In - in progress
Mar 30, 2005
940
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Northern California
Ric said:
It's FREE...

Jesus if anything get a GT4788R and sell it for 2 grand, and you can buy two 35r's

I dont think the company would like it.

He is doing them a good favour and they are repaying him with another good favour. If he gets too greedy and does that and they learn about it I do not think they will like it.

They will think he did this trade to make money off them.

Cheers,
Roy
 

figgie

Supramania Contributor
Mar 30, 2005
5,224
16
38
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Twin Cities, Minnesot-ah
This is assuming he can infact get it free.

Garret does not giveaway turbo jsut because!

They are either sponsored which means there is a clause in their contract not to resell what was given to them or the items are hot.

With that said,

Turbo for a web page design. Man that better be some real hot shit with custom coding in the back.

On a sidenote.

a 2.5L 1jz + a gt42r? 5500 spool up if you are lucky. That is GT47 territory on a 2jz but they have .5 liter more than the 1jz. Oh well there is always the "bottle" to help on the bottom end.
 

Neodeuccio

Addicted to boost...
Sep 30, 2006
846
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Schenectady NY
Wow, there are a lot more resposes that I thought I'd get...

I really should give a bit more info though. The webpage I'd be doing is for a college auto club, and the college has a deal with Garrett. Even if I could convince them to manipulate the system to get some monsterous expensive turbo to turn around and resell, the guys in the club are my friends, and I don't want to ask that of them.

As for what I'm looking for, the Supra will be my summer daily driver, so pump gas is a must. Also, though I love the straights, I like the corners more, so I'd like to spool as low as possible. I'm thinking 3k rpm or thereabouts. And I don't know if the deal with Garrett covers BB turbos, so for the time being, I'm going to assume not.

It sounds like the Gt35R (or it's non-BB equivalent) is the best liked for my concept. Also, if anyone could fill me in what A/R's are and hows they effect, well, anything, that would be a huge help. I always expected I'd have a lot of time to learn all this stuff before I needed to make a decision and now it's getting thrown at me faster than I'd like. Of course, for a free turbo, I'll do it anyway...
 

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
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I come from a land down under
A lot depends on the whole combination to which AR you end up with, when I bought mine I was revving the motor hard (8000+) so wanted a turbine housing that wouldn't choke the motor so chose a 1.06ar.

As a manual I was seeing 1 psi in 5th @ 1900 rpm and since changing to the Auto I get 2.5psi and the same rpm (Convertor isn't locked doing this test so it'll flare a little when nailing it)

I run a 12x24x4: IC and 3" pipes.
 

dbsupra90

toonar
Apr 1, 2005
2,374
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indiucky
yeah 500hp is a little vague. pump gas boost or race gas boost? a gt35r can make 500rw, but not on pump gas boost level.

be careful throwing around turbo sizing. a gt4088r and gt4088 are not the same size, nor is the gt35 and gt35r.

the bigger the turbo, the more hp at a given boost level, but at the expense of more lag. you can offset this somewhat by a smaller turbine wheel and/or smaller turbine a/r.

also to note, a bigger turbo wont nec outshine a smaller turbo at modest boost levels. example: a 61mm turbo and 67mm turbo will make around the same hp at 15psi. now, crank it up to 25psi and the 67mm will well outperform the 61mm.

id say, for 17psi or less for 500rw get a 67-70mm turbo.

for mid 20psi range for 500rw get a 61-64mm turbo.
 

logan

3 laws safe
Oct 4, 2005
109
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U.S-U.K
You would be better off just learning how to read a compressor map . Half the fun in modding a car is learning new stuff anyway.

Your typical choices would be IMO, gt35r , gt4088r and the t04z .
 

F_T_F

C2H5OH
Nov 12, 2006
255
0
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fort fun, colorado
the GT35r will be a little more responsive at the cost of power while the GT40 and bigger will be able to make that 500 RWHP but it wont spool untill later RPM's. it boils down to what you want
 

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
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I come from a land down under
ARGHHHHH the plain Jane GT4082 is SMALLER than a 3540R so flows less it's not until you step up to a 4088 that it flows more at the expense of slower spool/response...

People see "35" and think it's smaller than "40" when in reality it has the 40 Compressor section mated to a smaller Hotside making it a hybrid.