Hey guys, does anybody know what boost I should be seeing out of a 475 over stock kit on a LB7. Im seeing about 35 psi with spikes of 38 psi at WOT. Is this normal or should it be higher? Thanks :thumb:
Boost psi with s475 over stock
- Thread starter dieseladdiction23
- Start date
Rob is trying to work out the tuning now, but that was with twin tuning but the maf is still not dialed in and that's what he is working on now. The maf shouldn't take away from boost should it?
If the maf doesn't know how much air the motor is consuming then it doesn't know how much fuel to give it. Which could cause low boost.
Def seems like it should be a bit more... Don't know from personal experience but just from what I have seen!
This kit has been fighting me since it showed up on the porch, even hurt my back lifting it :roflmao:. I guess I check it over again, but im not sure what it could be besides the maf, its only idling at 27-30 g/s, and from what everyone has told me it should be 40 g/s.
I was seeing around 28 with a boost increase valve, I have a gauge for the big charger just haven't installed yet, im just reading total boost right now. It basically acts like the stock turbo is not even in play when I take off with zero smoke, once the big charger lights it goes like it should with moderate smoke which seems normal and egts get up to about 1400 degrees. Right now I can power brake it and it doesn't really want to climb past 1500 rpm, takes about 15 seconds for it to get up to 2000 rpm and that's when the big turbo starts to spool. Im at a loss
You big turbo should be pushing 1/2 of the total boost. On a stock fuel truck on an all out race tune, you should see 45- 50ish psi total boost.
Ok guess I need to figure out if its a exhaust leak or boost leak, and where. Or if its tuning and the maf is causing it to limit fuel.
That's exactly what I have been thinking. and I believe I would hear or see soot under the hood if there was a exhaust leak.
tuning? man i was getting 36 psi on my stock charger and stock fuel with one of nicks tunes. btw, my maf is disabled.
where's your gauge plumbed in at??? Jason's kits have a provision on the tube going to the y bridge if I remember correctly.
Can you hear the 475 spooling up? When I did my twin kit I didn't move my boost gauge and I only saw 30ish but that was because I was only reading the boost from one turbo.
Can you hear the 475 spooling up? When I did my twin kit I didn't move my boost gauge and I only saw 30ish but that was because I was only reading the boost from one turbo.
Can you adjust the wastegate on the stock turbo? Like did his kit come with a adjustable regulator for the wastegate. I know Trent sent one out in his kit, my buddy has one and we had to mess with it quite a bit to get it dialed in cause all it'd make was 35psi s475/stocker LB7