I apologize now for the long post but I appreciate everyone who responds with their feedback!!

What kind of boost do you guys see on your trucks? Another member posted a video of a truck smoking the tires and I swore he had a programmer because my truck wouldnt spin the tires in a car wash. Other users talk about insane power with their trucks so I have started paying attention to things a little more and want to share my observations to see if they are in line with other trucks. BTW, its not my goal to do burnouts, just trying to determine why my truck seems down on power. Also, just had the reflash and that didnt change anything.

I can hit 20 psi pretty easily. On a longer pull (like 0-70 without lifting) I can hit 28-30 psi in certain gears. I thought this truck hit closer to 40 when it was new but maybe thats when I had the trailer on it?? Maybe because it was warmer then??

As I am accelerating at part throttle I will be at 20 psi and say around 2,000 rpms. Then I can floor it, the engine revs up to 3,000 rpms (no downshifting) but the boost remains at 20. I can hear the engine rev up, It is accelerating, but the boost doesnt change with the rpm. Eventually it will if you stay in it but on my previous trucks, more pedal usually meant more boost.

For argument sake, I tried to do a burnout. I held the brake and built 20 psi boost. Then I floored it and released the brake and managed about 2 feet of black marks. Again, this isnt my goal with the truck, but I did it to prove a point about power.

They checked the truck for any codes today before I had the flash done and there were none. Help me out. Am I just expecting too much? Are your trucks seeing more boost? Does your boost fluctuate (seems no matter what I do I am between 20-25)?

 

Mine will boost almost up to 40 psi, even empty if i am getting on it.

I usually see in the 10-20 range on normal driving, but if I start to go up a long hill, say empty with the cruise control on the boost will increase to maintain the speed. It can easily go up to 30 or 40 or somewhere in between. As for the reflash, mine was a big difference, I have a job 3 as well, but had a bad TCM replaced at 600 miles. That TCM was a wrong one even though it worked good. So with the latest flash they had to give me the correct TCM. Big difference now.

 

My experience is pretty much the same as CAPRANG. I don't usually push the truck very hard, but the max boost I have seen is a little over 20. I have never even seen it approach 30, but then again, I don't push the truck that hard... bone stock

 

mine hits 30 when you step on it. Empty or towing. i'm bone stock

 

wehn my truck was stock i could hit 34 in 4th and 5th gear

 

I see a difference between when the engine is hot or cold. In the morning when the engine is cold (cold here is 35 degrees F), I see the boost stay at least 10 and as much as 20 even when taking it easy. Once the engine warms up, up to 10 with average driving, 20 if taking off from a stop light. I have not seen more than 25, but have not floored it yet. Have 1400 miles on a 08.

 

Under normal accleration its between 15 and 20 sometimes alittle more, when I floor it the most I get is between 30 and 40 but alot closer to the 30 mark

 

mine will run 20-30 most all the time and 35 once in a well if pulling hill with trailer on, I live at 7000 ft elevation it may make some difference, the one in shop would hit 36-38 when it is running this other one is not that much

 

I mostly tow about 15K to 16K with mine and I definately get close to 40 PSI when I am getting the rig up to speed to get on the highway or pulling hard.

I really can't remember exactly what it does empty but I want to think it was up to 25 PSI when i'm getting it done. Next time I drive it empty I'll update.

 

Caprang, I hear what you are saying with the power. I find the truck in stock form is kind of lazy. Under normal driving condition, pulling away from an intersection I am at about 2000 rpm and 20 psi boost. At this rate most people are accelerating past me. You really have to get in it to keep up. I would like to hear how other people find that truck in its stock form when it comes to power.

 

There is definately an initial lag on the stock 6.4 trucks. This of course is due to the wonderful EPA mandated emissions s**t. However, once the initial lag is over I have all the power I need.

I have a 4.30 RE and don't know if that makes a difference but I am sure someone smarter(just about anyone on this site) will chime in and set things straight.

 

First of all thanks for all the replies, keep them coming. I have always complained about the initial lag. When you arent used to that and arent expecting it, that can be really dangerous. I have adapted for that now. But I would swear this truck used to get close to 40 psi and now even in a 0-70 run I can only hit 30. Im not trying to race the truck but I think this could be an indicator that power is down.

2 things got me thinking about this. 1st, I went to pass someone on a 2 lane road a while back. I had lots of room so I nailed it and went for the pass. The truck down shifted one gear but didnt have that grunt I was expecting. I quickly realized that I wasnt going to fly around this car like I thought I would. At the time I thought I must have been at that perfect speed where it would only down shift 1 gear instead of really digging for the next one. I tried it a 2nd and 3rd time and I never got it to really take off. It would just smoothly accelerate at 20 psi.

2nd, my truck would barely spin a tire in a car wash. Not what I bought it for and just thought it was the lag (because my 6.0 would burn rubber at will). Then I see a 6.4 truck doing a burnout that would make the michelin man jealous and I think "thats impossible" but when I talk to other 6.4 owners I hear comments about how fast they are, how the power is incredible, etc.

My goal isnt burnouts and Im not saying I have something wrong....yet. But if others are getting 40 psi and I can barely hit 30 then I think there may be an issue. I was hoping the reflash would show some result but it didnt.

I find it interesting that half of you hit 35+ and half only hit 25+. Maybe a secondary question is "what is your boost and are you impressed with the power".

 

Now you got me curious. I am taking the 06 tomorrow but maybe I will take the 08 on Thursday or Friday to check this out. What would cause you not being able to pass? I know I have never had a power problem when I was up to speed.

 

It would accelerate but it was like I just gave it half pedal. It down shifted out of OD but I expected it to jump down to 3rd. I was doing maybe 50? This was my attention getter that something might be wrong. So I started running tests to see how much boost I could get. Im not 100% sure there is a problem but I dont know what else to test. No codes according to the dealer so what else could make some of these trucks barely hit 30 psi and others cruise closer to 40. And again, I remember seeing 35-40 last summer because I was shocked it went that high. Dealer said to bring it back if I felt there was a problem and the reflash didnt fix it. But I want to have some real data before crying something is wrong.

 

Not being able to pass at 50mph is definately a problem. I hate to tell you this bud but I think something is wrong.

I can't remember the boost but I can honestly tell you I have never had a problem with power when I am up to a decent speed. I know I am being repetative but something doesn't sound right. Maybe the dreaded regen?