how much boost do you guys make with your first gen 12valves? mine with an auto i see about 2psi driving around town. on the highway towing a big dual axel trailer i saw maybe 10-14psi. is this normal? this fall im going to put in my turbo out of my 2006. for now gonna swap exhousings and run it. just wan to know if its normal. thanks!

 

I probally see 0-5psi while cruising, 5-10psi on highway, maybe alittle higher and 40psi when I put the hammer down. Although Im pretty sure I hit 45psi the other day

 

With no mods to your truck its not far off but i think it's a little low. My 93 would boost 18 with a load. Did the pump mods and now its up to 27 with a load. The pump mods and the 351 turbo will wake it up. Oh sorry your pump is tweaked so I think real low. You sure you don't have a 92 model turbo with the big housing? Just remember you need gauges badly. My 92 would only boost 12 or 14 after a lil pump mod, then i cranked it on up and 20/21 with the auto trans. but towing it will get toasty. So gauges are needed. Good luck with it. Oh check your hump hoses and i/c for leaks.

 

60+

 

With only the AFC turned I could hit 18-23 PSI unloaded on the freeway but after I installed my GDS 60mm upgrade I can get 56 PSI almost instantly so I have to watch position of my right foot.

2 PSI you should be getting good mileage.

Jim

 

jim, is that under stock fueling? what mods to the afc do you mean when you say afc turned? just the starwheel or what? i wouldn't believe you could see 56psi under stock fueling with just the 60mm upgrade. if so, i'm gonna need head studs

 

Well YEA Bobby with your setup...LOL

 

Yes stock fueling, the only thing I had done to that point is to turn the fuel pin to the deepest side, when I upgraded my turbo I also built my 3" crossover and turned up the fuel but I have since turned it down about 2 1/2 turns.

This is a video I took before I upgraded my turbo, watch the Boost Gauge.





And then this was after the upgrade; I think it even sounds different.





And I have probably the only silent turbo they offer.

Jim

 

38psi with the stocker, 56psi with a HTT 60mm and nitrous. Non-intercooled though, so my boost will be higher than the intercooled stuff.

 

I'd say it's about time you intercool "Rustbucket."

To the OP, towing, with stock fueling, you should see more boost than that. Have you checked for a leaky intercooler?

 

it sounds like it's a bit deeper of a tone. and the olny reason the turbo is "silent" is because your cab is very well insulated to the point of being bulletproof did you change turbine housings or are you still running an 18cm? you sure buried that boost gauge. is that a 35psi? i'm gonna have to watch my right foot too when i upgrade to the 60mm.

 

Yikes What is too much boost for a stock turbo assembly... I mean will the internals of the stock turbo hold up to the 60 mm wheel with out over boosting? Not to mention the head gasket... I was thinking of going with the 60 mm upgrade at some point and a 16 cm non-wg housing but would it be smarter to go to a 14 cm wg housing?

 

40 psi is safe. for the HG and the turbo

 

16cm for you. because your truck is an auto.

You'll see a BIG BIG difference over the stock 21cm.

 

i see about 5 cruising but i have 4.56 gears in a 3 speed so it will be higher. but with the intercooler i am installing at the moment it will be dropping i imagine. 40 psi at wot at 1300 egts.