Drizzy

What turbo are you guys running on 370s for street only trucks? Have a 11:1 370 with a 212/218 or 218/223 cam, can’t remember right off hand. Currently running a billet VS 7875 .96ar. Put down 575 @ 12psi, but fell off at 5700 rpm. Looking to go big T4 or T6 w/ 3.5” or 4” down pipe and turn to 6200 rpm without choking up. Looking to be in the 600-650 hp at 12psi with running to turn up to around 700-750. Thinking the next gen VS 7875 83/75 1.25ar divided or S475 or S480 (turbine size/housing recommendations?)

94heritage

If you are going to change the hot side just go straight to an s475. The 171702 part number has made over 800 tire hundreds of times and is hard to beat at 600 dollars and change. If you think you are going to want more in the future go with an s480 and be done.

Drizzy

I figure the s475 will get me where I want. Anyone with input on experiences they had with different turbine sizes and housings? Feel like 96mm 1.32ar may be too big for what I’m looking to do with it.

03sierraslt

iTrader: (22)

What fuel are you running with 11-1 at that boost?

Drizzy

Flex fuel tuned and spraying boost juice. On E70 95% of the time.

94heritage

Using the box stock s475 with the 132 housing 96 turbine on a good flowing hotside we have noticed very little change in spool from say an s480 with an 83 turbine and t4 1.10 housing.

3 window

I’ve got an s475/83 t4 1.25 on my sbe 5.3, 243 headed, JFR 218 cam and I saw only 1.65:1 backpressure at 18 psi of boost (2 psi post turbine with my wastegate recirculated into the downpipe). I recently changed the wastegate to a screamer pipe and now I see only 1.3:1 backpressure at the same boost level. Pretty happy with that.

3 window

Sorry just realized it was a 370.

chris99gmc

What Heads are you running with that setup? I don’t know from experience, but from some of my previous turbo builds and from what I’ve read, you might be able to pick up some gains up top(while keeping your low end response) by going with a slightly larger cam and some higher flowing heads. If I had to guess, you’re running stock cathedrals.

i just ordered a Billet VS7875 for my 370 / T56 Magnum build that’ll be going into a 2wd 93 Toyota pickup truck. This truck will be driven strictly on the street, just like your’s..



I’m haven’t ordered a cam yet because I’m having a hard time deciding on whether to use 243 heads or 823 L92 Heads. After reading your post, I starting to lean towards the Gen 4 side, considering the power drop off at the top you mentioned.. I already have both pairs of heads with matching intakes in the garage. Any input?

chris99gmc

I read one your old posts with your Dyno numbers. From what I gathered, you were having issues with getting it tuned in SD mode and had to get it tuned with the MAF. IMO that could easily be the issue with why your power is falling off up top.