# what size turbo??



## Roop (Sep 5, 2003)

Okay, so I know a T28 is a good size turbo for a GTiR but how do I match the turbo code (T-???) to my size of engine?


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## chimmike (Oct 17, 2002)

you don't really match turbos to engines. you could use pretty much any turbo you want.

I'd suggest searching, getting a little more information would help you.

or check out www.sr20deforum.com and read thru the turbo section there.


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## Crazy-Mart (Jul 14, 2002)

like chimmike said you can take rather any turbo you want ... the pro use the flow charts of the turbo to calculate rather its well matched or not ... a nice turbo for small displacement engine to get low lag should be a 14b or a T25 with low A/r ration going to boost around 7-10 lbs... for bigger engine like the 2liter ... still a t25 with 64ar and t28 or a 16G are very nice match to the engine ... if you want major power gain take the turbo for the next sized displacement ... like swaping a t28 from a gtir to a 1.6litre but lag will be more present ...


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## boost_boy (May 25, 2002)

Turbocharger matching is very important or you'll probably be hating your car after you've put a big/stupid turbo on it. You do not want to put a T3/T04E stage 3 on a GA16DET or you'll be sorry. You do not want to put a T3/T04E stage III on a CA18DET and call yourself a street racer or you'll be sorry. It's best to do some homework on your motor's characteristics before chosing a turbo for your application. And you definitely don't want to put a 60-1 on a QG18DE(T) or you will be sorry without a spool-up kit .


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## chimmike (Oct 17, 2002)

ahahahahaha where'd you hear that from boost boy? lol


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## boost_boy (May 25, 2002)

> ahahahahaha where'd you hear that from boost boy? lol


 Research, trial and error! I just did that to my girl's CA18DET powered 90 sentra and I hate it on the street, but on the highway, bring it


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## chimmike (Oct 17, 2002)

no, I mean the comment about the QG with a 60-1 LOL.........you couldn't do 7psi on the QG with that turbo without blowing the engine


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## boost_boy (May 25, 2002)

I was actualy being truthfully sarcastic I definitely know the QG, QR nor the GA series would be happy with that turbo on the street because non of these engines will happily accept you revving them past 7500rpm without giving you some fuss. The displacement of the QG and CA will probably put them on the border line, but you're right in the fact that the QG might just pull an up-chuck with it's internals. When I had the 60-1 in my old sentra, that thing didn't start coming to life until around 46-4800rpm which is 70-80% of you guys' rpm range, but when it came in "Whoa lil moma". A good turbo for those would be T3/T04B stage 1, but you still may see some lag.


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## chimmike (Oct 17, 2002)

hey now, my rev limiter is at 6700  wanna fab some internals for me? I could use some pistons and rods 

THEN I could make some reasonable power...250 or so, without risk of blowin a rod, hahaha


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## Roop (Sep 5, 2003)

Okay, then; where can I find tech spec for all the turbos on the market. You guys are talking code numbers I've never heared of.


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## chimmike (Oct 17, 2002)

ummm.......try www.garrett-turbos.com or something......................there should be a good turbo dealer in your country......I'm assuming you're not in the states?


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## Roop (Sep 5, 2003)

I'm in the UK. Turbos are not really popular on petrol cars, here. Turbo diesels are much more common. I've thought about one from a diesel but would it work? I mean, a large capasity, low revving engine?? Would that work on a small capasity (1400cc) 6500 revver?
My buddy's 1900cc TD's power has packed up and gone home by 4K. Mind, saying that, it does seem to come in at about 2500 rpm's.
Whadda ya think? a goer??


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## chimmike (Oct 17, 2002)

what engine are you running?


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## mpg9999 (Nov 22, 2002)

Break out your calculator and start reading: http://www.gnttype.org/techarea/turbo/turboflow.html
here is my condensed version:

Ok, I thought Id post how to match a compressor to your engine. All of this info is taken from part x of suck squish bang blow in the sept. 2001 issue of SCC. 
First you need to figure out the pressure ratio. What basically determines this is what boost pressure you will run. This number will be plotted on the Y axis of the compressor map. To find PR: Pr=boost pressure (lets use 10)+14.7(atmospheric pressure)+1.5(intercooler pressure drop), then divide all that by 14.7. so, (10+14.7+1.5)/14.7=1.7823. 
Now we have to find out the the Intake air density, or Di. Di is equal to: (boost pressure+atmospheric pressure)/(R constant x 12 x (460+intake temp). R is equal to 53.3. so, Di=(10+14.7)/(53.3x12x(460+130)=.000065454. Just use 130 as the intake temp. 
From that number we need to find out the Mass Flow Rate, or MF. This is how much the engine will flow at x rpm. You will need to use this equation a few times using different rpms, ranging from 4000 to 7500. We will use 7500 in the example. So, Mf=DI(what we just did) x displacment in CI x (rpm/2)xvolumetric efficency. the displacment of an sr20 in CI is about 122, and you can just use .9 for volumetric efficency. So, Mf=.000065454 x 122 x (7500/2) x .9=26.951. 
Almost done. One more equation. We need to find Corrected Mass Flow, or CMF. CMF= (1/(14.7/13.95))xMF. so, CMF=26.951 x (1/(14.7/13.95))=25.576. Ok, No more math. Just do that again with some different rpms, and try different boost pressures too. You just plot the pr and the cmf on the compressor map. Some compressor maps can be found here,http://www.turboneticsinc.com/comp_maps/fig1.html . 
I hope I got all that info right... 
You can also find compressor maps at www.turbobygarrett.com

-Mike


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## Crazy-Mart (Jul 14, 2002)

that make sens


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## seRpwr (Jul 30, 2002)

im running a T25 at 9.5 boost... its a small turbo, but great for the street. its nice to smoke hooked up mustang GT's.
If you want good street power, go with either the T25/ T28. T28 uses the same housing as the T25, but has larger internals for the turbine and compressor.


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