Issues while in higher boost

[koukiKA240]

I have stock ignition system with NGK wires and BKR6E-11s gapped to 32.

While i reach full boost (10psi right now) the car does not pull as hard and the exhaust note changes. It is a newly built motor with 5k miles on it. It pulls fine and acts fine other than around 8-10psi. I have checked all my IC pipes for a loose coupler and have not found any boost leaks. Any advise of where to go from here?? I plan on pulling my plugs and taking a look at them after work today.~Sam

[DRIFTEADOR]

Have you messed with different gapping? try a little lower. what about the coil, has it ever been replaced? i would say if base timing isn't retarded that could be a cause too, but apparently there's a few people that get away with it here.

[Structure240sx]

what kind of turbo are you running again?

also i have seen with the jwt ecu's that around 9psi or so total timing will go up to about 18 but after getting past the 10psi mark it seems to stay at 14 degrees

[koukiKA240]

its a T-60-1 turbo and my plugs are gapped to .032. I have never had this kind of problem and it is very intermitent. the last 2 days it has been more often than not. My base timming is still at 20 btdc my coil is "new" to me, but came off of a junkyard car as mine failed for some reason durring te build up.~Sam

[get_up_mark]

u need to start pulling timing after 8 lbs of boost.

[koukiKA240]

i can only pull base timing so im not sure it would do much.~Sam

[NateDogg]

Chances are your gap is too big for the stock ignition system. Take it down to .028 and then let us know how it is.

[fiznat]

I'm not sure that its an ignition problem. Plugs gapped to big, or a weak ignition usually cause misfiring or missing, not simply a general loss of power and exhaust note change. You would be getting backfires and generally rough running.

It does sortof sound like a boost leak, but it could be a million other things as well. Do check your plugs, but hmmm I'm trying to think of other poissible culprits. Maybe a turbo way too small? Restriction in the exhaust? What about a bad tune? There are quite a bit of possabilities for this one. Check your plugs, but tell us more about your setup and your tune.

[Jookmasta]

i think u need to definitely get a wideband to ur car to see what ur a/f's are at that rpm. that will pretty much tell you where to start. also whats the size of your exhaust housing on the turbo?

[get_up_mark]

are the plugs a stage colder? if you subract base timing you will lose performance off and lower boost but you may want to do it just to see if your car pulls from 8-10 lbs any harder. also when is your car hitting full boost?

[koukiKA240]

tomorrow i wil finally have time off to work on the car. Im gonna finally be putting my z32 brakes on, putting a new fender brace on, and working on this little motor issue im having.

as for turbo to small and other tuning issues. We tuned it with a wideband to 10psi and my water pump let go, i have yet to conjure the money to go back and crank up the boost. So the tune is awsome and i trust SGP racing here in houston. My AFRs were a solid 11.5 from 3k to redline. I think its ignition, cause it feels like a miss, and it would change exhaust note if one cyl wasnt firing.

If it is a boost leak than how come its only sometimes?

thanks for the help guys.~Sam

[Jookmasta]

ya try gapping the plugs smaller...............and also look at ur plugs.

[C-Kwik]

If your exhaust noise is changing, it's probably because it is missing badly. Typically, when the spark is blowing out, it will feel a lot like you hit a rev limiter. Go with a smaller gap and/or a stronger spark(goil or amplifier). The change in note occurs because the fuel mixture gets ignited in the exhaust system. I had this problem when I had run a divorced wastegate and it spit out flames under the car since the mixture was igniting in the exhaust manifold and exiting the wastegate dump pipe. The noise was distinctly different as well.

[koukiKA240]

i get a paycheck tomorrow, im gonna see if any of the old car places or truck places have an MSD blaster SS so i dont have to wait for shipping.

Ill do the plugs as well. When i get off work tonight ill gap the plugs down more and see how that changes things.~Sam

[Structure240sx]

advanced auto parts ( dont know if you have any around you) carry them, at least the one near me does