97_ek

iTrader: (5)

Ok so I am in the middle of a 4.8 sbe turbo build with a Huron Speed AC T4 kit, and I have two turbos that I have pretty much narrowed it down to. I would like to have something like a PTE 7675 or a Turbonetics 7875, but cost is a big factor at this point, and both of those would actually be a little more than I need for my goals.

I have it narrowed down to a Turbonetics TC78 brand new from Huron Speed, or I can get a Turbonetics q-trim 7671 ceramic ball bearing locally from a guy that has it on his Mustang. His Mustang has gone 5.7x in the 8th, which shows it will be more than enough turbo for me since I won't get anywhere near those times. The used turbo has about 10k street miles on it with zero shaft play and it is also ceramic coated on the hotside.

I'm leaning toward the used 7671 since it will probably spool faster, and I'll be running a 6 speed. This is a 99% street car by the way. Very few track visits, just something fun to cruise in. Looking to make 600whp or so. The motor will has a LJMS Stage 1 turbo cam.

And go...

SPRAYED 01

iTrader: (22)

Go tc78 hands down. New turbo and will produce more power. Spool will be super fast.

97_ek

iTrader: (5)

I like the fact that it is new, but I'm not sure it's capable of more power actually. The exhaust wheel is pretty small on the TC78 which might choke it out up top. I would think the small wheel will help with spool up, but so will the BB on the other turbo. All the max power talk is probably pointless anyways though since I wont max either of them out any time soon. Thanks for your input. Anyone else?

LJMSJohn

the exhaust wheel in the TC78 should be the F168.... A q trim wheel is actually 68mm on the exducer as well.... and the newer designed F1 wheel will flow more. out of those two options... i would probably do the Tc78... ideally I'd probably look at 7875 if they were in budget.

97_ek

iTrader: (5)

Thanks John. I'll probably have to go with the TC78 to start with and maybe upgrade next year. Budget is running out quick since I decided to rebuild my suspension the same time I'm doing my build. I'll go with the TC78.

SPRAYED 01

iTrader: (22)

I vote tc78 if we are talking about the 78/75.

97_ek

iTrader: (5)

TC78 is not the same as a 7875. The 7875 is a ball bearing unit with a 75mm exhaust wheel. The TC78 is a journal bearing with the smaller 68mm exhaust wheel. About a $500 difference in the two.

RedRocketZ28

iTrader: (19)

Why not rock an On3 7875 if you plan on changing things up that soon?

97_ek

iTrader: (5)

I wanted to, but Jon at Huron Speed recommended against it due to the fact that they had some failures out of them in the past. I thought they had gotten a little better, but I don't know. I know the price is nice..

Superman09

iTrader: (65)

TC78 will work excellent for your set-up and goals, I would recommend that!

rotary1307cc

iTrader: (5)

Tc is a waste of money imo

97_ek

iTrader: (5)

So many different opinions...

I know Turbonetics has an excellent warranty, and I know the TC78 will provide plenty for my power goals with a relatively low price.

I wish I had real world data on how long the ON3 units are lasting now. I know for a fact the 7875 ON3 will make plenty of power. If it would last a year plus some, I'd be just fine with doing that. At this point im just teady to get it going. Car season is well underway. This build is sort of a "sloppy-style" build anyways except for the Huron Speed kit. I didn't mind forking out some money for a properly fitting setup with quality piping.

RedRocketZ28

iTrader: (19)

My old car started off with an On3 76mm and it did 606 rwhp on 13 lbs. Turned it up past that a few times but it was too small for the 6.0L. Beat on it for a few months, then switched to a Turbonetics 7875, and sold the On3 to a buddy who ran it on his Silverado. He then sold the On3 to someone on the forums who is now running it. Seems to be holding up well, and there are quite a few others running them without issue. For a budget minded build you really can't go wrong with one. Won't be out too much when you upgrade to a better unit.

skinnies

iTrader: (33)

I'll disagree, we have used A LOT of those turbos without one failure. Very reliable, and have made over 700rwhp on jy setups without an issue, for the price and only wanting 700rwhp or less it's a great turbo.

slowride

iTrader: (3)

Everybody hates it for the wheel size mismatch and it is set up more for something like a supra or something with smaller displacement and high boost, but it still works well. I'd be curious to see the difference in the other turbonetics compressor wheel sizes (66, 72, 76, 78, etc) with that same f1-68 exhaust wheel. I know in my friends 6l build the 7575bb turbonetics spools just as well as the 7268 he replace (or its to close to call). A TC uses a slightly smaller S size compressor cover vs the full t4 turbonetics. A manual corvette guy made around 1500whp with two tc76's so it's not like a turd or anything.

At the price point I'd have a hard time not trying the On3 7875 though.

95bowtie

I think he is saying waste of money because of the 68mm turbine. Not cause of failures that's for sure, turbonetics seem to be very reliable. Had the tc7875 myself for 2 years, now it's on a buddy car. Still very minimum shaft play.

To the OP I would honestly get with Viren at vsracing and pick a china 7875 up. You can find him on here or on FB.

I can't remember the last time I seen a china 76 or 78 fail. Or even a china gt45...last china turbo I seen go was matts pt88 clone but that was definitely due to the glitter in the oil from a failing motor.

transam69230

iTrader: (49)

Don't get a 76/68 or a 78/68 , and any TC unit with a 68 turbine wheel that has a larger compressor wheel.