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rockin' the JDM duct tape
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i keep reading about T61 and 60-1 and P-trim and GTQ and GT an BB and SPs and PHRs and garret and turbonetics and this and that. does someone have a good place for me to read up on what the difference between all of these are? why is a PTE67 bigger than a T78 and a GT42 is bigger than both of those? what the hell is going on here? how is anyone supposed to compare turbos?
 

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rockin' the JDM duct tape
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521 Posts
Discussion Starter #4
Craig King said:
i understand how turbochargers work. i just don't understand the differences in nomenclature. i have searched, and as far as i can tell the people on this board are either getting their information from somewhere else or are born with this knowledge. what search terms would you recommend i try?
 

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rockin' the JDM duct tape
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521 Posts
Discussion Starter #5
jtanner said:
The way most people compare turbos is:

http://www.moreboost.org

Jim
yeah, i've seen this site before. it's a great site, tons of good information, but doesn't seem to have been updated for some of the more recent turbos. any other good sites?
 

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I don't know much about turbos but I think I can help you out a little. The GT that you here about is a new wheel design that comes in P, Q, R, and S trims. These new wheels are supposed to have better designs that allow for better tradeoffs between power and lag. P gives the least lag, then Q and for larger turbos there are R and finnally S.

As for SP and Turbonetics and all these other companies, they are just who are making or selling the turbos. I think Garret, Turbonetics, Precision and ITS are the biggest manufacturers of the turbos. Places like PHR, BL, SP and everyone else just slap there names on them and sometimes modify them a bit. I think SP, PHR and BL all use Precision turbos in their kits.

BBs are different types of bearings used inside of the turbo. They are supposed to provide better spool and better midrange although people argue about whether it is true or not. i don't think BB turbos are rebuildable but I could be wrong.

The reason that the 67 is bigger than the T78 is because the numbers in their names are not representing the same things. In the PTE67, that 67 represents the size of the compressor wheel. The 78 in T78 doesn't, in fact I don't know what it stands for. I think the T78 has a compressor size of 66mm. The same thing goes for the GT42 which has a very large compressor wheel.

The best way to compare turbos is to compare their compressor/exhaust wheels and exhaust housings. Then you will also be able to see the differences that the newer wheels make when you compare an older style turbo with a newer style turbo that is the same size. Hope this helps, and please anyone feel free to jump in if I left something out or said something that wasn't quite right.
 

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VeilsideTT said:

As for SP and Turbonetics and all these other companies, they are just who are making or selling the turbos. I think Garret, Turbonetics, Precision and ITS are the biggest manufacturers of the turbos. Places like PHR, BL, SP and everyone else just slap there names on them and sometimes modify them a bit. I think SP, PHR and BL all use Precision turbos in their kits.

Actually Garret is the manufacturer of the turbos. Precision, ITS and Turbonetics just buy the parts from Garrett and assemble the parts. PTE, ITS and turbonetics also have some housings made to their own specs by casting companies. However the wheels and cartridges they use are mostly garret parts.


I believe PHR uses ITS turbos.

We use PTE. What we do is test and do the R&D on which turbos work best on the supras, then we have PTE build them to our specs. When they arrive here we go over them internally and do some porting on the housings and clean up the castings.


Hope this helps.
 

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VeilsideTT said:
I don't know much about turbos but I think I can help you out a little. The GT that you here about is a new wheel design that comes in P, Q, R, and S trims. These new wheels are supposed to have better designs that allow for better tradeoffs between power and lag. P gives the least lag, then Q and for larger turbos there are R and finnally S.

Actually this is not entirely true. P is the smallest turbine wheel while S is the largest but this does not always mean P has less lag. You must match the proper turbine wheel to the compressor wheel. For example a 76 Q trim will have quite a bit more lag than a 76 s trim. The Q trim turbine wheel is just not large enough to spin the huge 76 mm compressor wheel.
 

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Interesting. I assume that I made a decent choice in choosing the Q trim for a 67? I saw lots of people doing it so I figured it was decent setup. Is that wheel too big for that compressor? I have heard some people say that the P is beter suited for the 67 but that was after I bought my turbo.
 
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