Max stock boost?

[abrankod]

Hi all, I keep hearing a lot of guys talking about 40+ lbs of pressure on stock turbos etc, but my truck doesnt ever seem to top 30 lbs. It will spike at about 32 lbs and then fall back to 24lbs as the wastegate opens. I'm running the smarty on program 5 right now. No complaints about power, just curious as to the differences in readings from people, and if there is a reason, how do I make it produce more pressure?



Thanks,

Dan

 

[Bob4x4]

The smarty is able to produce good power at lower boost#s than other boxes at the same power level. On my 05 running a juice with the trailer I could see 42psi at 1/4 throttle. With the smarty same hill same speed same trailer 34psi.



Bob

 

[Mark1si]

Ive hit 50 with smarty on 4 and tst on 3/3 and thats with the plastic intercooler. SCARRY!!!!

 

[cerberusiam]

Hi all, I keep hearing a lot of guys talking about 40+ lbs of pressure on stock turbos etc, but my truck doesnt ever seem to top 30 lbs. It will spike at about 32 lbs and then fall back to 24lbs as the wastegate opens. I'm running the smarty on program 5 right now. No complaints about power, just curious as to the differences in readings from people, and if there is a reason, how do I make it produce more pressure?



Thanks,

Dan

The ECU opens the waste gate at about 32-34 lbs and holds the boost in the high 20's unless you over ride that behaviour with a box, DL'er, or boost fooler. There are a bunch or reasons for this that have to do with emissions, etc, that just causes a long discussion so I won't go into it.



Quadzilla makes a very reasonable boost fooler that will make 40 psi on a stock turbo and fueling and keep the EGT's in check. I think BD also has one on the market that is about the same in functionality and price.



I used the Quad fooler and it took 200+ degrees off the top EGT's under the same conditions and really made the mid-range and top end feel stronger. I have seen 41 psi with stock fueling and am sure it would make more with fuel.



I am also running a drive pressure gauge and watching it is really interesting. At 40 psi boost I have hard pegged a 60 psi pressure gauge. The drive pressures have got to be running 1:2 at that level. :-laf

 

[Elsbury]

I have the quad B/F on mine also. With the latest factory flash from DC my truck is runnin fantastic. I flashed her with the triple dog but went back to stock as the torque down low just feels better, especially with the boost fooler.

 

[JEstes]

OK, so the '07 defuels at roughly 32, but what does the '03 defuel at? Seems like I've heard 21 somewhere...

 

[PRawls]

My max has been 30psi. I can boost that through my Banks kit but it had one of those "do at your own risk" pages to go through first. I guess it limits it through fueling??

 

[cerberusiam]

OK, so the '07 defuels at roughly 32, but what does the '03 defuel at? Seems like I've heard 21 somewhere...

No, it doesn't defuel. The boost is limited by opening the turbo waste gate. the 03's should peak in the mid 20's give or take a few lbs.



The turbo on the 03's and early 04's is a bit different than the 04. 5+ and doesn't take the higher boost numbers well. Over 30 psi and it is out of its map and pushing hot air.