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Discussion Starter · #1 ·
I posted a similar question a few times on other boards but with no luck with a good answer.

Here is problem. I have installed a bunch of things on my truck (full exhaust, 4lb, 2.8upper, power plenum, idler, accufab, SCT, ported blower and so on...)

I did the port pretty soon after I bought the truck, so I do not honestly know what kind of boost I was seeing when I bought the truck. But I did dyno it before I did any mods and it dynod at 388rwhp (with 4lb and chip)

I did the port and after that I saw about 10-11lbs consistantly... i think i MIGHT have seen a 12 once or twice...I dynod it and got 397hp. Not the 25-30 most are claiming but at least a gain..... i didnt think much of it and went on...

well recently along with the 4lb, iv added a 2.8 upper, power plenum which are both supposed to add about 1-2lbs each... and also added an idler to prevent slippage... well Im now still only seeing 10-11lbs boost at WOT.

I went to dyno last week and dynod again with EVERYTHING on it... I was fully expecting to see at least 420hp.... well I didnt even break 400... I hit 399.... same dyno as previous times and almost identical weather....


so now with full exhaust, power plenum, 2.8 upper and idler Iv added 2hp... and still only seeing 10psi... I thought something must be wrong. I contacted my porter and he said he would be more than happy to fix the problem if it is indeed the port. Since then, iv been comparing pics of my port to numerous other ports by him... they are IDENTICAL... i really dont think the problem lies within the port, I think its elsewhere... but WHERE??

i looked at the actuator, and it seems to be working properly.... I looked at my vacum lines and they seem hooked up correctly.... truck is running fine, just not enough power or boost....

does anyone have any ideas on what to look for? before I go out and take my blower off and send it away to get checked out, i wanna make sure iv covered EVERYTHING... but im out of ideas....

btw, i have no boost bypass installed, its back to stock.... would that cause a problem like this???
 

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Discussion Starter · #2 ·
ohh, forgot to mention. I called JDM and told them I needed a re-tune because Iv added all this stuff. They saw my 399hp dyno chart and said it looked really good as far as the A/F is concerned.... said it really doesnt need a new tune... but could maybe tweak a little???..... but he agreed that I am defenitly missing about 20-30hp with the mods that I have... and I should be seeing more boost for sure...

the A/F was 12.1
 

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I'm not sure what the factory limits are on the Lightning boost bypass, but mine would fully open and put me into limp mode after about 14psi. I could only peak at about 5 psi then.

As you say the mods should be making more boost and the only way I don't see this happneing is with your boost bleeding off somehow, which will affect your overall power of course.
 

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00bolt said:
i looked at the actuator, and it seems to be working properly.... I looked at my vacum lines and they seem hooked up correctly.... truck is running fine, just not enough power or boost....
Those are the only two things I can thing of other than mabey the blower, hopefully somebody who know's more about this can chime in. Good luck with it.

later
brain
 

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what kind of effects would the boost actuator have, if you took it off, and put it back on at a wrong the wrong angle or how it is not supposed to be? when i took my s/c off to paint it, i removed the acctuator, and when i was done, i put it back on, but didn't pay attention to how i put it back on, i just tightened it back on, didnt know there was suppost to be a certain way it goes on.

i see you checked that, but have you checked the other lines?
 

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Maybe a vaccum leek somewhere? because with my basic mods I'm right there with you on RWHP. A friend of mine has the same problem he added additonal mods and he's slower by almost a half second and he's peeved too.
 

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The ignition system is a common reason for disapointing results.
It could be that at 11lb or 399hp you're simply running out of spark energy, it just can't light the fire at those pressures and its not something you can "feel", and unless its pretty bad you won't see it on a dyno either.
 

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You know, I had kinda wondered the same thing, except my truck is basically stock with a PSP FASTair. From what I remember, everyone had said in cold weather with a -crap, I just got attacked by a mosquito- FASTair or other setup, the boost would go into the black, and mine doesn't even hit 10PSI.

Can't wait to dyno this truck. It seems like it might be low on power... My best of 14.6 at 92mph would kinda indicate that as well. Even with a crappy 2.2 60' time.
 
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