boost too high?

[toecutter]

i have a '90 gsx basically stock, with a fuel pump and a mbc. its set to about 17psi, but at around 5,500 at w.o.t it starts to kinda fall off, i was wondering if it could be becasue the boost is too high, i hit fuel cut a lot also......just wondering should i turn down the boost and see if that helps, it never did it when i was running stock boost

 

[ricky_rockstah]

definitely doesn't seem to like the extra boost, I've got my MBC set to right around 15 psi in my '92 w/ my walbro and that seems to work the best w/ everything else still stock.


just turn it down a little until you can get something to tune w/

 

[DSM90AWD]

Free up your exhaust (porting of cast pieces and free-flowing exhaust) and you will see much better results.

For now turn the wick down, especially since no tuning devices/datalogger is listed

 

[boostinaintez]

Yes turn your boost down and free up your exhaust. Well put dsm90awd.

 

[toecutter]

well i have a full 2.5" turbo back. im just gonna try to turn it down to about to 13psi or so, till i but the 255lp in, i only have a 190 then i also need to get a fpr, but with the 255, the fpr and 550cc injectors and a 2g maf i really shouldnt have that problem right? because that all goes in soon, im just waiting on the afc

 

[DSM90AWD]

im just gonna try to turn it down to about to 13psi or so, till i but the 255lp in, i only have a 190

The 190 rewired will support 400WHP so is not hurting you at this point. Unless you already have the 255/AFPR may want to spend the money elsewhere (EPROM, Injectors, MAFT)

 

[toecutter]

the thing is, the guy "said" it was a 190lp, but im just gonna change it just to be sure ya know, but i already have all the things

 

[4g63t]

yes turn down boost and invest in a logger to make sure your not knocking and timeing is not being pulled then slowly turn boost back up after the upgrades.

 

[oldman]

Boost leak test, you shouldn't be hitting fuel cut at 17psi, fuel pump aside.

 

[toecutter]

it was very cold out that night, the guys i know with dsm's said that might of had a lot to do with it