CasperCasper

Hey all,

Going to try and throw a turbo on my lq4/l92 over the winter. It's got a 225/230/111 with heads milled .030. Thinking of going with a 7875. Is this too much cam for this setup? I'm a bit concerned about the compression ratio as well. I'd appreciate your input.

Thanks

jasonsnova

i have a ljms cam specd . its almost identical to that , my car is a 6.0 with ls3 heads so almost identical. except im running a t6 s475.....it lights off great . im very happy with it.
with the 7875 it should come in even sooner.....

CasperCasper

Do you think the 7875 is a bit small for this application? Would an s475 make more sense?

ls3fox

7875 is gonna be too small for a motor that size i run an s475 it lights fast and makes more power then my 275 drag radials can handle at 12lbs

Jimbo1367

3pedals

iTrader: (3)

The 78 75 has too small of a turbine for a 6.0. Get yourself a Borg Warner S475/96. A 1.32 ex housing will work, but a 1.1 is available which will help it spool much earlier.
The 225/230 111 cam is not too big, but it has a bit of extra overlap that you dont need. I would degree it to a 109* intake centerline, and run it.
I personally had excellent success with a 227/235 114 cam in my 6.0 with LS3 heads, S480 combo.
Barrett

CasperCasper

Thanks for all the advice. Im green to FI and love to hear about your setups. I'm thinking I will go with the t4 housing option. Does this sound reasonable? Ultimately I want the power to come on early as possible.

CasperCasper

Also, where would you recommend purchasing from? I see a ton of these on ebay for 500 bucks or so.

ddnspider

iTrader: (26)

6 speed or auto? If 6 speed and you want power as early as possible, that turbo is not too small. It'll be great at lower rpm's and spool quick which will pair well with the stick.

truckdoug

iTrader: (25)

I used a six liter with the billet 7875 and it was awesome. Killer street combo. Eventually though it became limited by the turbine wheel and created backpressure ratios of 3:1 on only 16 psi.

But if I were shooting for a fun 600 wheel on pump gas and water/meth- I would not hesitate for a sec to run one again. I got bit by the s480 bug and while it makes a ton of power, it's not as snappy as the 7875.

3pedals

iTrader: (3)

Goals for the combo are certainly where the decision should be made.
My perspective is 800rwhp. If you are not looking for anywhere near that, then yes the 78/75 could work, but it will still choke the 6.0 up at higher rpm, which I don't like. I don't recommend it on any 6.0.
On my 6.0, s480 combo, I ran a 92mm turbine, 1.1a/r housing, and the thing spooled at 3K, and was an absolute blast to street drive with my 5spd on 10psi. That was 600rwhp.
​​​​​ It layed down 800rwhp on 16psi.
Barrett

CasperCasper

My goals definately lie at 600whp. The car is from 1973 and I know it wont hold up to much more than that. So now Im torn between the 475 and the 7875. I really like the idea of the snappy 7875.

btw i appreciate all the help. If any of you ever come to vancouver come by and we'll melt some tires

ddnspider

iTrader: (26)

600whp goal=7875 hands down. Will make a great street car.

Kfxguy

iTrader: (1)

3pedals

iTrader: (3)

I guarantee that when you turn the boost up and try revving it out a bit, you will see significant back pressure. This may not hurt you too bad if you plan to keep the boost fairly low and never push the combo.

ddnspider

iTrader: (26)

Nobody's arguing that at higher boost its out of the efficiency range....OP's goals do not require that.

Kfxguy

iTrader: (1)

Game ova

With a billet precision, my 6.0 made 820/908tq and that was at 21psi and 14 degrees (dropped to 765/900tq with the On3). For what his goal is, the 7875 will be fine.

CasperCasper

So once again Im back at the 7875. I cant forsee wanting more than 600whp. For starters ive got a stock 10 bolt posi. Car has a built richmond super t10 that I got from a race car guy so we will see how she holds. More or less mystery internals from a very reputable seller in NC. The bottom line is this car just wouldnt do well with a whole lot more than its got, hence why im shooting for a conservative power number. I will keep you all updated and make a vlog build thread, videos will be posted on my youtube channel ( westcoast wrenchin' ). Thanks again!

truckdoug

iTrader: (25)

link a video here and i'll sub you. I do the youtubes too and try and sub all ls1tech folks