i have the tvs and and recently switched from the 2.9 pulley to the 2.7 pulley.i made 22psi on the 2.9 and was hoping to pick some boost up with the 2.7 but i still only make 22psi.the 2.7 makes more boost earlier but dies off above 5k rpms and maxes at 22.with the 2.9 i made 299 whp and 257 wtq on a 75 deg day and only made 287whp and 267 wtq on a 95 deg day with the 2.7. i know the heat hurt the numbers but i dont get why im hitting this wall.i dynoed on the same dyno both times so its not that.any ideas of why im not picking up any boost or power when dropping pulley size.iat's were maxed at 130 on the 2.9 and the 2.7 was 135(it was also 95 degrees.)mods are in sig. im also in the process of putting 3 inch piping in to see if that helps any.ideas?

 

clogged cat perhaps?

 

maybe but i would think the boost would increase

 

if you were running a 2.5 cutout and exhaust, there's no way your exhaust was restricting that

 

its the factory exhaust with 2.5 cutout before the muffler

the car only made 1hp less with the cutout closed which i thought was weird.

 

oh you've got it way back there.... have you looked into belt slip? are you running a shortened belt or oversized tensioner pulley?

 

yea i have the stg 2 belt and the tensioner

 

Tune?

 

the tune on the 2.9 was 11.5 afr and 22.5 degrees timing w/ no knock.so when i went to the 2.7 i went 11.9 afr and 18 degrees timing w/ no knock. i could maybe run more timing but we just called it a day thinking it would be safe and still make more power on the dyno.

 

im thinking belt slip or the boost regulator is holding you back... i thought the 2.9 was supposed to make 25psi stock... so you should have been above that... someone will chime in with the correct answere but this is something to look into

 

Are you using a mechanical gauge or the stock electric gauge? Our sensor maxes out a 22psi (2.5 bar) therefore, a mechanical gauge is needed to be accurate. Hell, it's needed anyway to be accurate

Just throwing that out there....

 

its not the the boost bypass already tried pulling the line off and plugging it so that the computer couldnt cut boost or anything.the 2.9 i believe is 22.5 psi and the 2.7 25 psi give or take a little. isnt 2 bar like 29.4 or something, plus im going off what hp tuners says not the gauge if it makes a difference im not to sure about that one

 

HPTuners reads off the MAP sensor, which is the one Wicked was referring to. Get a mechanical gauge and you should see the correct boost.

2bar is 14.5 PSI boost, 3bar is 29 PSI boost. Pretty sure our cars run 2.5 bar sensors (21.75 PSI).

 

well im not gona get a mechanical gauge just to accurately see what my boost is, but the power difference still doesnt make a whole lot of sense.does 12whp less on a 20 degree hotter day seem right to you guys when dropping 2 pulley sizes, even tho iat2 was only 5 degrees hotter on the 95 degree day.

 

Bah, I need more sleep. Yes, stock sensor is 2.5 bar. Thanks Dainslaif

Humidity. Temperature. Tune. Dyno. All are factors to dyno numbers.

 

you changed your tune... changed afr and timing... thats where the hp went. and something isnt right with your tune, or your setup. you should be well over 300whp