When I do a 3rd gear pull, it reads 28psi. When I'm at the drag strip, according to my Zietronix's log, max boost is only 25psi. Why the difference? Can it be that since I'm going through all the gears quicker, there's less boost at the dragstrip? So does it mean I'm only pushing 25psi and not 28psi? When you set your boost on 3rd gear pull, shouldn't you be able to hit the same boost pressure regardless of whether you're drag racing and speed shifting through all the gears? Am I the only one with this issue or is this common for tubo cars? Someone please enlighten me. Thanks

 

Boost in 1st and 2nd gear is always lower than the higher gears, unless you're using an electronic bc. Max boost on the stock turbo is seen around 3,XXX RPM depending on other mods. On the strip, max boost is only seen @ 3 grand in 1st gear and also depends on how well the launch is. After that, depending on your shift points, 6,500 - 7,500, your revs always stay well above that 3 grand mark. As I'm sure you know, the stock turbo cannot keep up 28 psi at high rpm's. Understand?

 

Yep, pretty much what Thegame said.

You see 28psi on the street is probabaly because you got WOT from a lower RPM, which place a higher load.

 

I have a 20GLT, sorry I didn't mentioned it in post above but I don't think that makes any difference on my boost question. The ZT has a feature that tells you what the max boost is that you hit per run. It only stores max boost that was hit regardless of which gear it was in. So this is normal then?

 

20G-LT is going to taper at higher RPM's. On the 3rd gear pull, you see 28psi at like 4000RPM and it tapers off to 25psi probably by redline.

At the dragstrip you never see 4000RPM.