That is kinda what it feels like,The 75 spools like a mofo but the boost is half of what it should be and I know this thing has more jam in her,What do you suggest?big head or bite the bullet and find a new ihi?
LB7: lb7 475/stock low boost issue
- Thread starter dirtydmax
- Start date
That is kinda what it feels like,The 75 spools like a mofo but the boost is half of what it should be and I know this thing has more jam in her,What do you suggest?big head or bite the bullet and find a new ihi?
You could just out a new stock wastgate on the IHI. Or contact Yellowchevy on here and let him trick out your current ihi
There is no fixing a broke wastegate flap if that's the cause and generally is. Hopefully if it did break, it didn't go through your big charger. Your going to need to pull the hot pipe off the back of the stock turbo, grab a mirror, a magnet on an extendable rod, and then while using the mirror to look at the back of the turbine, use the magnet to see if the flap will move open or closed easily. It should not move unless the arm does. If it does move with the magnet, time for a new/used turbine housing with a good wastegate flap.
I found this out about them breaking as well as mine broke not long ago and what your describing sounds a lot like my case.
I found this out about them breaking as well as mine broke not long ago and what your describing sounds a lot like my case.
Whats your egts reading and does your truck smoke like a freight train. I would think running a max tune set up for twins if that was the true amount of boost you were getting that your egts would be way high and the smoke would never clear up.
Also when you tested the waste gate with your air comp was it going through the regulator or was it hooked up directly to the gate.
Also when you tested the waste gate with your air comp was it going through the regulator or was it hooked up directly to the gate.
Egt's are high,while cruising with 1-5 psi I can be 700-900 and smokes quite a bit.I can hit 1500 easy on a big tune wot.When I used the comp I put the air directly to the gate bypassing the reg,I can hear the flap squeeking in there but il have to inspect.If the flap is ok could I put a big head on to fix the issue and ditch the reg?
Something else is wrong if that's the case. The reg on my stock wastegate works just fine and I'm driving a lot of fuel through my twins.
You won't be able to tell from the outside or by noise. Even taking the c clip off the arm and trying to turn it for resistance can give you a false feeling if it's good or not
You won't be able to tell from the outside or by noise. Even taking the c clip off the arm and trying to turn it for resistance can give you a false feeling if it's good or not
Pulled the dp and flap is still sound and attached,What else could it be?Also lubed the linkage and all works as it should but cant break 28 psi.Maybe a big single or a 66 for the 75 is in my future if I cant figure this out,I am getting a low voltage maf code as well as high volt fuel somthin,not sure if related.
You need to track down your codes first and get that out of the way. Could be your problem..
I was seeing 38 and spiking 40 with no regulator. Something else is going on. I'm now getting north of 50 easily and 1300.
The codes are po102,po113 and po463.The 463 ait is a new one but the maf voltage low has been there since the twin install,Think it's maf related?
Ok,I checked the maf pid and it's reading 3-5 g sec and from what I understand it should be 40+.Can I calibrate my maf or is it in the tune?My tunes are locked so I hope I can fix this without playing phone tag with my tuna,Thanks for all the great posts and Helping me fix this thing:hug:
I'm not sure on what the spec is for the maf gs.. But I believe to rescale it it's actually in the tuning. Prolly just call your tuner tomorrow.
Did you have any maf problems before the twin install? Check the maf and make sure it's facing the correct way. Should be where the cut out in the side of the maf is facing the air filter. If it's backwards it's not gonna work. Get some maf cleaner from the parts store and clean it while your making sure it's facing the correct direction.
Got some new tuning from Kory and while the truck feels a lot stronger I am still only making 29 lbs boost so im at a loss,dont have a clue what to check next.Could it be a weak cp3 not making rail in the upper rpm where I need it to make the boost? Suggestion's?even wild ones?
having an edge insight is handy in this situation. Have you checked rail pressure during a wide open run? I can check and see what my insight says about the MAF reading if you would like. Running the same set up with the same tuning.
That would be great,So nice having a diagnostic tool like dd and everyone on it:hug:
yes. I used the wrong type and it didnt work for me. I ended up going and buying a more expensive one. I think it was like 30 bucks. But still, you should be higher than 29 psi even with a wide open tube going to the stock gate.
Woops
manual boost valve but open or shut doesn't make a difference,this is what is fu*kin me up.Dont know if im getting boost from the atmo or ihi to try and pinpoint the prob.Tested the system and no leaks.