Help: S472 twins with LB7 stocker
- Thread starter $chultz38
- Start date
i run about 45 to 50 on my truck my eco tune hits 36 so either boost leak or tunning sucks. you have a big head or anything on stocker?
I am having fuel issuse and i had a manifiold come loose boost was down and running hot with just the s366.
It's not the tunning, I have tried a PPE vavle on the stocker but didn't like the drive psi. I guess I am also asking if a "out of the box" 171701 turbo will work as good as others. I am thinking of going to a 475 instead. Is the exhaust side of the turbo different 472 vs 475?
first off is your cp3 stock and if so you wont bend rods quite yet need more fuel than that. next do a big head wastegate on your stocker twins run good on a 1:1 ratio if your pushing 15psi on stock mostly only have 15psi on s475. bd waste gate come set at 27psi nice and safe for stock charger. if all fall through try a different tune. i can throw all the fuel my stock cp3 can make and my twins will clean it up. look up white lightning from dansvill 765wrhp stock lbz motor doing it off of air flow not just fuel.:thumb:
You can't bend rods on stock cp3 fueling:spit::rofl: Maybe you need to doing a little more research on that one
Not really with the model you're talking about. That turbo should work just fine if its T6 and a 96mm turbine.
need to pressure test the system and rule that out first , second I would need some info on what your running for tuning , depending on the fueling 30 psi may be very low or "normal" , who built the kit ?
I would not tune your waste gate strictly on your drive pressure readings , there are many more things to consider , Drive pressure isnt always as evil as some make it out to be , after all drive pressure is the engine behind the turbo , too much is no good , not enough is no good also , often times being 1:1 ratio wont even net you the most HP , or the best EGT's ( in a compound setup any way ) , and going to the S475 will have zero effect on boost numbers . If you want some help checking a few things out or dialing things in give me a call . Trent 801-599-3922
The are plenty of reasons to use a S472 , just depends on what your building the kit to do , I have built plenty of kits using Billet S472's for towing apps / street trucks , works excellent if you arent building for peak HP numbers ( under 700 hp ) , also consider the compressor wheel exducer is identical between the 2 , only a smaller inducer which equates to about a 5 - 7 lbs per minute loss , but the billet S472 flows 1-2 lbs more than the cast S475 so ..............
I built everything on the truck and I'm using Rob's tuning. Is the 171701 an 96 or 88 mm exducer ? That might be the problem. I had the 472 sitting on a shelf and use the truck for towing mostly. The two boost gauges read about 15 and a little over 30 at WOT so its close to 1 to 1. I am using a LBZ CP3 and a lift pump also so I should have the fuel. With the PPE vavle on the stocker the 472 made less psi and the drive psi was higher also.
It appears to be a 88mm turbine according to your part number. It shows to be a 1.32 housing to.
The exducer is a 88 , most refer to it as a 96 because thats the inducer size ( turbine OD ) the turbo itself is not the problem but not nothing else about the kit so its hard to help with out more detailed info , better start checking for leaks , and also checking to see what your commanding for fuel and make sure its actually fueling what it should.
x2 test for leaks
you could be seeing higher egt's cuz of a leak.
log a run and post it after checking for leaks.
To compare EGT's I would need to know what elevation your at and what size tune your running , get me that info and i can tell ya what we usually see under those conditions .
A little up date- I found a small boost leak at a clamp. But as I pressure tested, alot of air was coming out of the pcv vent is this normal? I had the tail pipe plugged and a cap and hose over the turbo inlet with a tire vavle steam in it and was putting about 40 psi on the system. The psi bleed off fairly fast but if I put my finger over it the "leak" stopped. The truck runs fine and doesn't build crankc ase psi when the truck is running so I can't have big problems right?
Thanks to everyone that has been helping on this, Trent is a hell of a guy!
Thanks to everyone that has been helping on this, Trent is a hell of a guy!