Upon closer inspection , I realized that my pair of turbos are actually Precision Turbos and not Garrett . I am very upset about this , 'cause I specifically asked for Garret units , since I never had any bad experiences using them , the foreign supplier says that they are made for Precision by Garrett and it 's the same thing , now I heard that before and the turbo only lasted one month !! . The price that I paid was for Garret units which are more expensive at $1250 vs the cheaper $1100 Precision units . What should I do , this is keeping me back from completing my car ! .
I already sent them back to my local supplier and told him to send them back , what do you think. Anyone have any bad experiences with precision ??. This is the exact turbo the sent me .

 

I think carl had his pt67 die after 3 dyno pulls, he has a thread in this section about it. That is just 1 turbo though, I havent heard of many if any failures at all? Usually ive heard about the turbonetics BB units failing.

 

PT turbos are Garret based turbos.
PT cast their own turbine housings but will use (though not always) standard Garret comp housings and chra's though.

 

the picture contains an i.d code SC34.

www.nolimitmotorsport.com lists all the Precision Turbos.

under SC34.. there are two.

SC3431 which has a TO4E 57 trim compressor ( 2.23 X 2.95) and a T3 hot side that is a .48 A/R turbine housing w a stage 2 ( 2.559 X 2.228 ) turbine wheel. $742.


SC342 has the same compressor w either a .48 or .63 turbine housing but w a smaller stage 1 wheel ( 2.559 X 2.121 ) same price.

49 lbs/minute times two turbos 1418 cfm or 738 rw rotary hp max.

but not w either of those hotsides..... way too small. you need the .82 A/R hot housing w a stage 5 wheel.

realize that you won't have alot of midrange w these turbos.

as to Precision, a well known person who literally wrote "THE" book on turbos has them on a short list of excellent turbo vendors. 'nuff said.

you just have the wrong hotsides. i know as i have already done that... huge backpressure and v high egts.


good luck,

howard coleman

 

Actually , They are not theSC34 , what I have is supposed to be GT3071R's , I just put up that pic to show what they looked like . Howard , aill the .63A/R on the GT30's be too small too?.

 

Not if your running 2. I'm running 2 Percision GT3071R's on stock ports. Both are a .63 A/R on the turbine side. I went with a t3 inlet, 5 bolt discharge without the internal wastegate hole.

-Alex

Edit: BTW, Precision has been around for quite some time. I've never heard of any issues with the company. Like someone already stated, they are all based of Garrett turbos. They just use their own turbine or compressor housings. The rest of it is all from Garrett.

 

I wont be running stock ports , I did a semi pp on my motor with whole new intake (pro-jay) too . How's it work whend do they boost ? , whats the power like ? , any problems with the turbos ? , they said that their BB CHRA is original Garrett and that just the housings are Precision.

 

I don't have the car up and running quite yet, but I should have some results by the end of the month. I only have ~20k on the stock motor, so I didn't bother pulling it just to have it ported. Anywho, I'm going with a custom intake manifold made by myself, it will be similar to the Hogans 20b intake manifold.

Kevin went with 2 Turbonetics T04E turbos on his half bridge. I think he went with a .64 a/r, so you should be just fine. I think the next step up is .8 something, which would be to large IMO. Try giving Kevin a PM, and he should be able to answer any questions you have.

I havn't had a chance to go over flow charts of the GT42RS, but I think my results will be very similar to it. 1 GT3071R is slightly over half the size. From what I hear the spool up on the GT42RS isn't that bad, and the twins should spool faster. Try searching for a post from Xcessive in the single turbo section. He has a post about a GT42RS on a large streetport. The HKS T51R SPL is probably a better comparision though.

-Alex

 

Yep , I'm thinking that a pair of GT30 turbine wheels will be large enough and a .63 a/r per rotor is good too , actually I did get some specs from a former racer (who has since gone over to the Mustang camp) who ran a half bridged motor , he recommended t3/t4 turbos with 56 trim compressor wheels and stage 3 turbine wheels in 0.63 a/r housings.
I used a 1.22 a/r on my previous half bridged motor without ANY problems , so I figure a 1.26 a/r (0.63 X 2 ) should be better ..........., less backpressure , more power with great response .

 

PM'd you...

howard coleman

 

i loved my pt67, was great, and by friends bought another 2 with excellent results.. I cant wait to get my gt35/40R from precision.. oh yea precision turbos are garrett .

 

But Howard , correct me if I'm wrong , but isn't the stage V wheel almost the size of a P trim wheel ? , and you're saying to use two of these in 0.82 a/r housings ? , those will be wayyyy too big ! , there are people here using one P trim wheel on their single !!. No wonder you're saying "realize that you won't have alot of midrange w these turbos" , those turbine are taking forever to get up to speed ! .
I got your pm , I appreciate your help , but I think the original turbine / wheel spec . that I got from the other member will work well for me , the main reason that I went with twins is because my car is to be primarilarly a street machine , I desire the power of a big single with good boost response and drivability (the response of my last turbo was good , but it could have been better) , twins usually producer an earlier and wider power band with similar peak power to a single , because the smaller lighter turbines spool faster, going with such a large turbine on each will definately negate all these benefits .
The only change I may consider is maybe the larger 0.82 a/r housing , with the Gt (stage III) wheel which flows more than a similar sized T series wheel, the guy who recomended these specs tried and experimented for more than a year before he came up with the combo. , he made well over 550 WHP and ran 9's , I think he may be right about what he said , thanks all the same.

 

I decided to keep the Precision / Garrett turbos after I was given a 12 month warranty. I'll let you'll know how my build turns out.

 

i will be refiring my car by mid week and will post the results. i am going w .82 housings and stage 3 wheels.

howard coleman

 

I happened to put one of the turbos in front of a fan in my bed room and guess what ! ,......... the turbine began to spin !!!! , is it supposed to do that at such low pressure and flow ?? , I'm wondering now it I'll get boost too soon with the port I'm running !

 

Well when I blow into the turbine side with my mouth, it spins! So yea, it's normal. That's BB's for ya!!

-Alex

 

Yep , mine do that too !!

 

Are these the same turbos ryan woom uses in his supra? (percision)