Engine/Transmission (1994 - 1998) flat spot on the top end

[NBowlin]

im running a 215, 4k gsk, 0 plate/no plate, 370's, 19. 5* timing, 50+ for boost, and my engine seems to pull really hard up to a point (im not certain if its rpms or boost though) then it doesnt fall off a table persay, but it has a deffinite leveling off. now as far as smoke it smokes pretty heavy at the bottom and ends up top with more of a haze. i have ordered lasercuts from Piers hoping to fix this, but they are back ordered.



do you guys think they will fix my problem, or is there something i am over looking? thanks

 

[KennyM]

Sounds like you need twins, or a larger single charger.

 

[chrleb1]

Sounds like on top end you have more fuel than air, and it just starving. I would get a turbo setup before the DVs. I bet when you power falls off your egts are climbing like crazy.

 

[Forrest Nearing]

at 50psi I'd hope he's running a pretty large single or twins!



but yes, a larger hot side will definately help out w/ the top end charge.



might need to give it a little more timing

 

[NBowlin]

i run a usb1, and i am not sure as to what i run for boost, i need a new gauge. all i can say is that is gets to 50 in a hurry, then who knows where after that. i am not actually sure as to where the waste gate is opening though. i have an inline regulator that was provided backed out as far as i could get it. i dont want to block the it until i can see where it actually goes.



crap i didnt want to here i had a turbo problem. i just got this thing. way it goes though huh



can the usb1 be used in a twins get up? with a 3b perhaps?



keep talkin guys i appreciate the help

 

[Forrest Nearing]

when you say inline regulator, I'm assuming you're talking in the boost reference line to the wastegate? is there any sort of bleed orifice? I'm assuming you're saying that you've got as much boost going to the wastegate as possible, right?



because if it WAS blocked off/not opening, that could explain why it's choking off up top... and would definately be a situation you need to look into if you've only got a 50psi boost gauge!



I wouldn't guess you've got turbo problems at this point... could you just be getting used to the performance and wanting more?



also, if the power curve changed, it may actually be pulling as hard up top as it used to be, but the acceleration in the mid range is so violent that up top seems soft comparatively?



just shooting in the dark



Forrest

 

[NBowlin]

the regulator deal is between the afc and the wastegate. Pius included it with the turbo. i may be infact blocking it off entirely though cause i never hear it. i will try backing it down until i can get a respnce out of it. i know it works cause i turned it the wrong way at first and it went at 30psi.



so if the wastegate dont come open it would choke up the ole motor huh. i hope that is it. cause this turbo is spose to be good for quite a bit of power.



i completely understand what you are saying about getting used to it. i think that is what the stinkin bombing road is lubricated with.



thanks.

 

[chrleb1]

Air flow is key for making power on a diesel. I'm not sure what size exhaust housing the usb1 comes with, but having a small housing will limit your flow. Thats why wastegates are nice. If you are hitting over 50 lbs you could be out of the effective range of the turbo. The best thing to do is call Pius and ask them for the most effective boost. Like an hx-35 becomes inefficeint after 34 lbs of boost. So when you get that number from Pius, try and set your wastegate for that boost level. Also if it has a small housing it could be used for twins.

 

[Forrest Nearing]

I think once you get that 'gate set up right, you'll find your missing top end.



might be time to get a boost gauge that reads above 50psi



Forrest

 

[NBowlin]

the usb1 accourding to pius is good to 52 or 57 i dont remember which. yeah the 35 poops out at 24-27 isnt it, but it will hold 35ish. i know these usb's are being turned higher than 50's.



the outlet off of the hotside is 4" rather than what ever that little 35 was. i am not actually sure what the housing size is. there is a picture of it side by side with the 35 in my readers rig deal.



i know i need a new gauge. who makes a white faced 100# guage that uses a red light? it should be interesting to see where its actually going. when you are moving down the road it comes from 7-10psi to pegged in maybe 2 seconds. you think the gauge could be messed up?



i wish i wasnt where i am right now. it is making things more difficult than they need to be. any of you guru type needing a vaccation and dont know where to go? i hear iceland is nice this time of year i cant wait to get this truck back to the states where someone who knows what they are doing can fix everything i am cobbling up. i think it has a lot of potential.



you guys are great thanks for working with me. i will take all the help i can get.