Building boost and Atmospheric conditions

Onefast99gsx · 08-01-2005

Does the outside air temp and whether it's humid out have a direct impact on the amount of boost you build? The reason i ask is because the other day my MBC was set about about 22psi. The following day i cranked it over a 1/2 turn and tested the car and i wasn't building any more boost. Sunday was much hotter than Sat.

Thanks!

**JET** · 08-01-2005

What is your setup? Especially the turbo/wastegate.

Onefast99gsx · 08-01-2005

PTE 50trim, cut divider, internal wastegate(the newer internal gates). Hallman MBC,

Thanks.

**JET** · 08-01-2005

I am guessing your actuator isn't adjusted properly and the wastegate is blowing open. Either that or your MBC is sticking. You can clean it if it is older it may have carbon in it.

Onefast99gsx · 08-01-2005

I'll check both. Since i have 2 slimline fans the actuator is easy to get to. I'll loosen the actuator arm up, hold the flapper shut with one hand and retighten the 2 nuts with the other hand.

thanks much...

**JET** · 08-01-2005

Actually you will want to take the arm off the wastegate and extend the arm. Adjust it until it takes a little pressure to get the arm back on.

Jacek · 08-02-2005

In regards to the question, the air temp and air pressure have no effect on how much boost you build. For that is all with the boost controller spring compression.

niterydr · 08-02-2005

Quote:

Originally Posted by Jacek

In regards to the question, the air temp and air pressure have no effect on how much boost you build. For that is all with the boost controller spring compression.

Wrong.
Air temp can have a direct effect on how much 'boost' you can build. If your near the end of your efficency range, you can 'pin' what you can build for boost. (aka can't come up with the boost). Also if your tapped for your boost controller at your compressor cover, that'll change with weather conditions. Where is the boost controller tapped in at?
A boost controller is an item used for increasing demand on top of what the wastegate provides, pending how its hooked up. The boost controller can be influenced by outside temperature/pressure, and other motor/efficiency options, it just comes down to the setup most of the time.

**JET** · 08-02-2005

Swanny is correct. Usually you will see a small change though. I have seen a max change of 2 psi in a car depending on the weather.

Jacek · 08-02-2005

I apoligize, my text book did not go into the detail of efficiency. I guess I'm gonna call it a bad book.

niterydr · 08-03-2005

Quote:

Originally Posted by Jacek

I apoligize, my text book did not go into the detail of efficiency. I guess I'm gonna call it a bad book.

Real world experience. When John's talon had the 60 trim, the boost would range from 37psi (I guess we hit 40psi one very cold night out racing according to the aem) to some days it wouldn't make over 32. Its a slight swing, but since he is seeing a few psi swing, it could play into effect.

Pushit2.0 · 08-03-2005

On that note, it was only for about a 1000rpm then fell off on the top end. But man did that car pull hard at that 39psi. It was way faster then the 32psi at the track, on my 11.0 run....

94talonawd · 08-28-2005

i think ur boost will change 1-2 psi depending on whether. correct me if i am wrong