i searched this topic and found no difinitive answers. here is my question. i have a 4 lb lower and 2.8 upper and an apten port job. when i am on the highway (70 mph) and i punch it the needle goes directly to 8 lbs and slowly climbs to 12 lbs. this is like in 95 degree weather. i have replaced my boost actuator and done the boost bypass mod. what is keeping me from getting 13 lbs as soon as i go WOT? does a tune control the boost levels at a certain position? my last trip to the track i ran a 13.8 at 100 but i had a slight headwind and humidity was high. the altitude here is around 3500 feet. also i have the jlp ram air system. what gives? is it the heat? sorry for all the questions but this has me puzzled

thanks

 

I have about the same setup and have been trying to take it out and make a similar run, but we've been having thunderstorms and every time I have time, it is wet.

Tomorrow's weather looks better and I will post a response as soon as possible.

 

thanks, was wondering if anyone actualy read my post

 

Yes we did

Your boost sounds a bit low. I have pretty much the exact setup...Apten port, 4lb lower, 2.8 upper...When I stomp it my needle goes way over into the black...i would guess around 15-16psi. I think I need to hook up my Phantom boost gauge now and see what it really is.

 

Hey Bryce,

Sup Pal
I see you replaced the boost actuator and did the boost bypass mod, I'm assuming the heat and humidity is playing a part in your troubles As you know I have a 4 lower + 2 Upper + Wasp Port,
I swear to you that I can go 1/8-1/4 pedal and get 10+ in a mili-second (at low mph). And If I go WOT (AT ANY MPH), I will INSTANTLY get at least 15/16 maybe more, (like ShockTherapy just said he does)

Temp DOES play a part, but I've never seen mine slowly climb AT ANY THROTTLE POSITION if I go WOT ???. Last night I went out for a niiiiiiiiice ride, thermometer was reading 69 (WOO HOO) and at any MPH all I had to do was give it a quick stab and WAM, the needle flew waaaaaaaaaaay past 10.

If you take it out at night when it's cooler and there's less humidity, do you get the same results ???

 

same setup 2\4 combo and port.

Yesterday morning when temps were at 69 I punched it and hit 14# very quickly. I shut her down at 80. Not sure if it would have climbed more or not. It hits about 12# immediately and then within a second or two hits 14#.

In the heat it is slower. It will hit 12-13 and barely hit 13 1\2. In hot 95deg weather 13# is about as good as it's going to get for me.

I will say you should hit well above 8# when you punch it. Maybe the boost actuator needs adjusting?

-Rich

 

Thought i had the same problem 4lb lower 2.8upper apten port and long tubes. I'm in Very southern louisiana and temps are about 95 here too with 70% humidity. If i go WOT i see 10lbs and if i let it climb into the 5500 range i'll see 11 or 12. You seem lower than me and i thought i had a problem. Check you boost actuator and make certain the butterfly is closing properly.

 

what would be the easiest way to do that? i've screwed with it when the charger was off but havent done anything while it was on the truck. i havent tried it in cooler weather yet, still hot here in texas. i have never seen more than 13 psi but i dont usually stare at my boost gauge either, should have gotten the electric boost gauge like i had planned to. thanks guys, and Rob begining to wonder if you got a fluke lightning (one that was never meant for the public) but you got it anyway later

 

check all your vacum lines, maybe one got loose when your blower was put back on/taken off, only think I could think off besides what everyone else said. Hope you get it worked out. My L will hit 13 with in a sec and climb to barely 14 when it's cooler out. By the way you gonna make FFW...later man.

Paul

 

Could it be that Rob's Lightning got a fluke.




TEAM PSP
____________

Don

 

There is a big variable that we have to eliminate before we can compare notes. That variable is kickdown. The rpm at the blower is obviously a direct function of engine rpm. If I bring mine up to 70 mph and go WFO, the truck downshifts and the boost goes off scale. If however, I give it all the throttle I can without making it downshift, it goes to about 9 pounds (since the motor is only turning about 1900) and it climbs from there as the revs go up. The kickdown function is one that gets a bit scary. I nailed it at about 65 and it downshifted far enough that it went right to 5200 rpm and was climbing from there. It is no wonder that engines have died from freeway kickdown. I'd like to know if there is a way to alter the program to prohibit any downshift that will exceed about 4500 rpm.

Oh, there is nothing in the chip or ECU that limits boost. Boost is pretty much a function of blower speed, efficiency and throttle opening.

Are you seeing 8 pounds before or after kickdown?

 

Bryce,
Honestly, if you are at 13 now in hot weather then you will get a minimum of 1# of boost more in cooler 65-70deg weather. You are probably ok for total boost. The slow build up though.....

When I adjusted my B\A (boost actuator; tired or writing that out)
I loosened the front bolt just a little and then went to the back hidden bolt and loosened it. I bumped up the B\A about an 1\8 of an inch and tightened it down. I Took it out and did this a few more times, even going way up. My finall setting was moving it up about an 1\8th of an inch.

Another thing, the slow boost build up could be belt slip. Before getting a aux. idler kit. I put on a 1\2" smaller belt. It did get me
1\2# that I was missing.

-Rich