5.3 Twin On3 70mm's
 

So my Precision 62/62 went out again. So in 1 year, I have one rebuilt twice and now the other one needs rebuilt. At $500 a pop this gets old. So here is my question. I know some people have had good and bad luck with the ON3 turbo's. Precision is supposed to be a good turbo also and I have spent way too much money on them. With that said, would the twin 70's here be a good match for a 5.3?

http://www.ebay.com/itm/3-Performanc..._Parts&vxp=mtr

On the PTE62/62's the car ran a best of 118mph! My 62/62's had an Exhaust AR of .58. These On3 70's look as though they would bolt right onto my kit. I just run stock 5.3's with no upgrades except the ls9 head gaskets, Chinese Head Studs, Patriot Gold Springs, and the XER273 224/230, .581/.588 on a 114. I run E85, no intercooler, and 50/50 water meth. My IAT's are never 200 degrees. Since I am using junk yard engines anyways, I thought these would be worth the risk as long as it is a good match. If one goes bad, $250 later a new one is at the door.

-This is a daily driver but mainly local and strip performance is just as important to me as street manners. Willing to give up a little performance on the street.

I also run a trans brake.

that changes my perspective on precision... lol. freeman is doing twin 70's on his 5.3, theirs a mustang on here that has twin 70's on a 5.3 also. im still pondering on doing that with my lq4 also since im not too trustworthy of the other ebay turbos besides the gt45, but, the ar is too big on them. if you do twin 70's on yours ill do twin 70's on mine. like sarg said, they have pretty small turbine wheels so i think we would both spool pretty good.

I say do it!

what are you doing with your 6262's then? are both trashed or just one?

I'm saleing the one good one that was just rebuilt. Pm me if interested.

Thanks all, I think I am going that route. I just wanted to make sure they weren't too big for a 5.3.

It may be the turbos are defective but id look into why u keep trashing turbos. If you bolt these on and they take a shit then somethings wrong somewhere on the car. Whats happening to the 6262s? Wheel touching case, toasted seal, broken shaft? Sorry for makinf u explain it again if you already have. I heard precisions warrantee is garbage and some folks have been having issues but 3 in one year seems odd

How can "HE" be trashing turbos...??? All you do is bolt em on, feed em clean oil and make sure you have good drain back.... His turbos are mounted high so draining isnt an issue... he is not pushing serious boost on them so impeller speeds are definitely in range...As long as BOVs are working and he is not surging the compressors, the turbos should keep working and for a long time.

Basically, the turbos he is getting are just junk from Precision. I agree he should be getting a lot more use of his turbos... I have had a T3/T4 cartridge style turbo on my busa for the last 3 years and 7k miles, pushing 14-20 psi through it and never have had an issue.

Seems to me that Precision needs to step up and resolve the issue.

He has a diff thread explaining his set up and issues with the turbos, check it out for your answers

If you go this route, I'm certainley interested in your results. Good luck man.

Yeah thanks all. Yes, I have done everything required to not have any issues but they keep going to shit. I have -10 drain lines with no restrictions, turbo's are level, I have -6 oil feeds (recommended by precision) and they keep going out. The warranty only held up once but I still ended up paying $500 for a rebuild. While the one is still good and rebuilt I don't want to throw it on.

It looks as though we agree the 70's specs would be okay for the 5.3 so we shall see what how they will perform.

Still running methanol?

Not methanol but E85. It is normally around 85-90% Ethanol. My cousin has the same set up and his twin turbo's (Not precision) has been running fine for over 3 years.

I thought you were on Methanol, im sorry, lol.

Oh, and no worries, im a FIRM believer in Ethanol and its abilities, i dont believe we need need intercoolers either, lol

My roommate is running two one 76mm turbos and seems to spool them just fine with his stock LS1 and T56. Im running a single on3 76mm on my 5.3 truck and love it, but Im considering buying another and building a twin setup

I would think the 76's would be too big for a 5.3. It's too bad the GT45 isn't smaller or I would get them in twins. They are even cheaper and free shipping.

I would think 70's is as big as you could go on a 5.3, hence the thread to make sure I wasn't getting myself into trouble.

That's crazy that two 76's spool pretty good even with that t56. Its hard to believe that would be streetable. But i guess the smaller turbines help street all. I'll definitely be doing twin 70's on my setup now

I agree. Well, if anyone is interested I will be saleing the one PTE62/62 that I just paid $500 to have rebuilt. Only asking the cost I paid to rebuild it since I don't trust at some point it could still go bad on someone else. Have the rebuild sheet also.

Any idea on when you think you might do this?

If I can get the money together, I plan on ordering and having it running for next weekends TNT.

I might try twin gt45s on a 5.3 with ls9 cam next year. I mean. How late can they come in? 4500 rpm or so.
Hell, ill just restall my stall ;)