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I'm looking to get the new GT25 series of turbo's from Garrett. I'm unsure of what compressor and turbine sizes to get. There are a bunch available. I can't find much information on these new turbochargers either. I can't find a place that sells them for a decent price either. I can find a ton of information on T25 turbo's though. Anyone done some research on these particular turbo's? Maybe you know of another turbo that's well suited to out engine. I want 75% or higher efficiency and small size. I don't know what I'll be able to boost to, but I think that 15psi maximum before efficiency suffers is allright. Anyone know? I need to pick a turbo!!!

 
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on a stock engine your not goin to be able to run 15psi. you can safely run 6psi, 8psi with an intercooler, timing retard, and a different map sensor. alot of guys i know use the map sensor from a grand national.

 
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EvilDave666: I have a general idea of what I'de like, but I wanted to see if anyone else on this forum has sized a turbo to our car yet.

01civ01: I know that I'm not going to be running 15psi on a stock engine. Maybe I should have explained better. I want a smaller turbo that will work for me at lower boost levels (3-4psi). I do want one that is capable of about 15psi though. That's 'cause I will be a "boost junkie". Modifying my car and increasing the boost. 3-4psi is what the stock fuel system can handle (according to HKS) with a horsepower increase of about 30-40hp. The map sensor issue will be resolved with a Missing Link check valve. Lookey here: Synapse Engineering

Now, if anyone knows of compressor and turbine sized for the GT25 series of turbo's, then please help me out...

Thanks

 
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I can ask down here in Mexico, they would be chaper cause the make em' here and send em' to the US, just give me the size and i'll give em a call for ya.....

 
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Oh seriously? They make them in Mexico? I had no idea. Allright. I will tell you everything I need...

I want a GT25 series from garrett. The following information is what a GT2510 from HKS has.

COMPRESSOR:
-Wheel- 63 Trim - 47.7 Inducer / 60.1 Major
-Housing- 60 Inlet / 50 Outlet - 0.60 A/R
TURBINE:
-Wheel- 62 Trim - 53.0 Major / 41.7 Exducer
-Housing- GT25 inlet / Internal GT25 oulet - 0.64 A/R

I want a T25 Flange.

I want it to be ball bearing. Actually, the GT series is dual ball bearing as far as I know.

No internal wastegate. I will use an external one.

I want the water cooled option. Not air cooled.

I also want the VNT turbine flow control option. If possible.

I hope I gave you enough information? If you could find out anything for me regarding this series of turbochargers, then that would be great. Thanks in advance...

 
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Grey, how did you learn so much about turbos?

 
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The net baby! The net. I just use www.google.com and search for anything on DIY turbo's. Then I read. Plus this site was helpful when I knew nothing at all. Sometimes I look through other forum's for information. It seems like not many people have a clue about turbo's though. The information is kinda scattered all over the place. It's up to the DIYer to bring it all together. I'm thinking of putting together a DIY turbo page for the 7th gen civic. Stay tuned. Concept stage first, then application stage. Hehe...

 
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Grey, you are my new role model[IMG]i/expressions/laugh2.gif[/IMG] For real though, thanks for the sources!

 
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Grey, the basic philosophy of sizing a turbo is to choose the turbo with a flow map as close as possible to the engine flow map.

There are several books which can help explain this better:

something like this perhaps

I have a more advanced 2001 automotive (engineering) design book, that explains the real deal, from the chemistry and stoichiometrics of fuel all the way to the tires. It is very detailed, I will get you the name of it shortly.

It's an EXCELLENT resource, compact yet exhaustive. It is quite costly. The book is roughly $110 to $125.

Name to follow.

-m

 
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Yeah, I tried this thing a while back: TurboFast - TurboMap
Now I get that I should be using a T3 "Super 60". I'm estimating various psi's at various rpm's though. Plus I have no idea what VE's our engines have at various rpm's. I'm guessing that they're pretty efficient at 3,000rpm's though. Past that I think the efficiency drops. With a new camshaft that would change though. New exhaust would change that a little bit as well. Hell, new intake as well. It's tough to know what size to use.

 
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as for me, my turbo project is gonna begin with internals first.... then work my way over to the actual turbo compressor/turbine, etc... i spoke to the local machine shop today, and he mentioned to me that building up ur engine first is a better idea, that way u dont tear up ur internals when u install the turbo. just remember, that your engine has to be prepared for the extra power, meanin ur gonna have to beef up ur pistons, bearings, rings, cam, etc... before adding a turbo running higher than 5 psi or so...
im doing a lot of research into this, so i'll let you know wut u i come up with. u can email me at bluenvy@attbi.com for more direct conversation/info about this topic...

 
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Yeah, I realize that I'll have to modify the internal eventually to allow me to run more boost. For now my goal will be 3-4psi. We don't have internals available for our cars yet, so that's a mute point. I hear pistons are coming out in December though. [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

 
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Another turbo DIY thread? VNT? What is this? If it is a variable gear turbine housing it wouldn't really be necessary on our cars, if going with a T25, cuz spool time would be nearly instantaneous as is.

 
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Yeah, sorry. I love talking about turbo's!

Um, I would like bragging rights that I have a VNT turbo. That would rock I think. Plus it'de spool up quicker and a wastegate wouldn't be needed. Some sort of boost controller would have to be hooked up to it instead. Interesting stuff though. You're right though, it would be overkill. Hey, overkill is good sometimes though. After all, our cars are made to be rather efficient. Why not go with an efficient turbo?