SchuttsR1

iTrader: (1)

Hey folks,
I was wondering if I could get some help with my rear mount set up. This isnt going to be going on a LS engine but there are many diy guys on here that I think I might be able to get the info Im looking for.
I was wondering if some one may have a formula to find the proper sized ar and compressor size for the boost I would like to run on this engine? Also whatt is the best return oil pump and warning system out there for the remote mount? Lastly what size wastegates are people using?
What I will be running is a 5.0L quad cam engine. I was looking at a master power T70 turbo a .68 AR with a 46mm wastegate. I was looking to run 6psi to start and would like to be at full boost by 3.5k. My red line is 7k on this engine that should give me a nice power band.
Let me know your thoughts guys.
Thanks.

jridenour31

I wouldn't use that turbo on a 5.0 being spun to 7000. A gt45 has a much better turbine to keep backpressure in check. How much power are you trying to make? If everything else I set up properly, you don't need to choke the motor with too small a turbo just to get it to spool.

SchuttsR1

iTrader: (1)

Looking for around 450rwhp at 6psi. Right now it sits at 320 Na.

HRHohio

I'm running an On3 Performance 76mm Ball Bearing turbo. I started off with a .96 housing, but ended up purchasing a .81 exh housing later. I'm pretty happy with the setup. Spools up pretty fast. I would avoid going any smaller than .81 AR to avoid choking the turbo at 7k. Also, best advice I got so far (and passing on) is to stick with stock manifolds and to wrap the exhaust from engine to turbo to keep the heat in. That helps keep energy/power going to to the turbo. I'd go with a 50mm wastegate.

SchuttsR1

iTrader: (1)

Thanks for the advise I may have to look into a T76 and a bigger wastegate. When are you seeing full boost with your setup? Im sure mine will differ as my displacment is smaller and I have a manual. I was planning on wrapping the factory exhaust and was going to keep the factory cats on the car. What pump are you useing to return the oil back to the engine?

jridenour31

The bigger compressor on those 76's is essentially useless because the turbine isn't big enough to support the power the larger compressor is capable of, especially if you're only after 450hp. The larger compressor will just add unnecessary lag. Also, I'd ditch the cats. They're just going to be a restriction and if one happens to come apart it is going straight into the turbo. Small piping that's wrapped like crazy will help spool a lot. A 46mm wastegate is more than enough, especially if it's getting priority.

HRHohio

How big a turbine do you think it needs to support a 76mm compressor?

jridenour31

At least a 75. Backpressure will be too high trying to max out a 76mm with a p-trim.

HRHohio

Keep in mind this is going on a rear mount. I think any of the mentioned turbos will work fine. I think the p trim will actually be better for a rear mount. If it were a front mount, I'd agree 100 percent. need that exhaust flow. The on3 76 is working fine on my setup, and that's going through stock manifolds and cats.

OP, I'm seeing 6lbs boost at the top of first gear. I get to 10psi early into 2nd. Works for me. I've also been plagued with boost leaks, so stay on top of that.

jridenour31

Yes, a p-trim will spool faster but I still wouldn't use one when trying to spin to 7000. As far as the 76 goes, there's no reason for that large a compressor when a: only looking for 450hp and b: using a p-trim. That bigger wheel is adding 100% unnecessary lag.

jridenour31

With a low power goal of 450, that 70mm with a .81 housing would be fine.

SchuttsR1

iTrader: (1)

Thanks guys. Its a high compression engine so I dont really want to press my luck with taking it higher than 6psi. Many of the other FI versions on this engine is for superchargers and there isnt any turbo information on it.
Do you guys run any filters in the oil feed line and any warning system when the return pump fails? Also if your using a wideband where are you placing them on your rear mount setup?

HRHohio

I agree. When I was doing mine, I knew that I would not be satisfied for long with only 450 rwhp, which is why I stepped it up to the 76mm Ball Bearing. This gave me room to grow. As you know... boost is addictive! I'm glad I went a step up, but that's just me.

No, not running any filters in the oil feed line, and no warning system for return pump fail. Billowing white cloud of smoke will be my pump fail signal. If it fails, it will be very quick and no need for another system. (my opinion).

Wideband - on my y pipe, drivers side, just behind stock O2 sensor.