blackout

just wondering if anyone else has run into this, or any suggestions for a potential quick fix. here's the situation- runs perfectly fine at 10 lbs boost pressure; no hesitation, sputtering, nothing. but once i raise the boost to 14.5 lbs, it sputters. nothing really obnoxious, but i know it's not supposed to run like that. i also smell fuel real strong... not like the rich smell i've almost gotten used to, this smell is like pure gasoline. i haven't changed the plugs since i got the car in august, and it could probably use a new fuel filter as well, but i'm just sort of curious as to why it doesn't act up until i raise the boost. btw this is a very basic setup, all stock save for exhaust, fmic, and an aftermarket mine's vx-rom tuned ecu. my boost controller is a greddy profec b, if that helps any.

Junon

hm.. 14.5 is a little high i think (the turbo passes its efficiency range at 15). your ebc could be overboosting. i ran into a similar problem with my old sr, it would sputter/bog at peak boost, and when it tapered off and held, it was fine.

basically, try running it at 13psi, if you have the same problem. then you have a big fuel issue. SR's as it is run rich, so grab an SAFC =P

in all honesty, theres no point in pushing past 12psi on that setup. the stock wastegate cannot handle past that to my knowledge (maybe even less, i didnt pay much attention to it).

sorry for the jumbled post, at work and my mind is fried.

blackout

i've heard mixed reviews on running that much boost, so i pretty much leave it at 10 lbs 90% of the time. but it does not happen all the time, i've run it at 14 plenty of times before and it was fine.

if all else fails then of course i'm going to drop the boost though.

WarriorBlaZe

Definately need to upgrade that fuel pump if you haven't already. The stock 370cc injectors can't keep up with that much boost either. You're running the risk of locking one up.

NX2KDET

Could it be your plugs, are you using NGK BPR7E and gapped at .028

240dreams

I've been running 14.7 psi in my SR for a looong time now. Change the plugs to one step colder (heat range 7) and gap them to .028.

blackout

my bad, i have a walbro fuel pump, can't remember the specs. i think 100 liters per hour. actually ma motorsports warned me about the injectors as well but i've personally witnessed several people running 14-15 lbs on stock fuel delivery with no problems. it's a fairly rare occasion that i boost that much.

not sure about the plugs either, but that's my first step. are these part numbers correct for the rwd sr as well? (assuming you have a fwd motor...) i'm sure they could use being replaced anyway. along with the fuel filter, and a quick inspection of all the fuel lines.. i was just wondering if anyone's seen it before. thanks for the input guys.

Moriar

if its the 100lph, then its a stock replacement, u want the 255lph.

I reccomend changing fuel filter to the 300zx twin turbo fuel filter, and plugs.

blackout

that's it, the 255. thanks for the refresher!

i'm wondering if it doesn't already have a z filter... again, thanks for the reminder. all things that will likely be done tomorrow- but definitely before track time sunday.

john 89

Mine did that when i raised the boost, it was the spark plug gap. try taking your plugs out and regapping them to something smaller. also, i ran 14-15 psi all day long on my stock turbo/injectors and it was FINE