Yesterday at etown i trapped 114.5 @ 14psi. So tonight being that it was much cooler out (maybe 30 degrees less) i decided to make some pulls to see how she felt. I was getting a solid 15psi all the way to redline. My intake temps were 34 degrees C as oppose to yesterday at etown which was 60 C. What a fricking difference!My car fells fast as hell tonight.
But i am feeling something above 6800 rpms. Im not sure if it is simply that my car peaks out in horsepower at this point or if i am getting alittle break up. But, the acceleration doesnt feel as smooth after 6800. It isnt rough feeling just not as powerful and smooth. What does this mean? Do i need tunning up there, or an ignition amplifer, or is it simply that 6800 rpms is my peak horsepower? I am not sure what "high rpm break up" feels like. Does it actually feel like the car sputters or is it just not as clean feeling. My car doesnt sputter at all...just feels less clean/smooth.
I am trying to decide what route i need to take next. Is it more tunning up top or an ignition amp that i need...or both?
thanks for the help.

 

your car should pull smoothly to 8500 rpm even with stock ignition. my car did and it had as many mods as you did. even with blown coolant and water seals. tuning tuning tuning

 

oh yeah mods are:
full exhaust, intake, m2 med ic, power fc, 1300cc inj, fuel pump, act street/strip and 9.5 flywheel.

Thanks vosko...i guess you are leaning towrds more tuning....like you have been telling me.
What does break up actually feel like...is that what i described above, break up?

 

opps

 

if you get break up sometimes it feels like a loss of power if its really bad the car will studder and misfire

 

Check your spark plug. They might be fouling out. Also get cold plugs! Just some advice!

Jp

 

Have you checked your AFRs? I'd suspect your mixture is off up there (too rich maybe?).

Brian

 

well i did notice that my injector dudty cycle jumps up a bit up there.
I have been tuned by dave at KDR. But he lets off early around 68-69 rpms. I think i should go on a dyno around CT and see what my afr's are way up there. If my afr looks good above 6800 does that mean that i do not need tuning? Or can a tuning issue still exists even though afr are good and not over rich?
thanks

 

another question....if i do get on a dyno...and i am rich...i think i will be. Can i reduce fuel via lowering the pim volt for the given rpm range? Or is this sort of rough tune not specific enough for this high in the rpm range.

 

Matty, I get the same "slight" hesitations above 6500 rpms - they're not really hesitations but not completely smooth - I'm sure it's tuning since Dave although being an awesome mechanic and installer, he's a conservative tuner. I didn't seem to feel the unsmoothness when I was non-seq but it's definitely not a super clean pull to redline - especially in 3rd and 4th gears. I think an ignition amp would help smooth it out - colder plugs like 10s or 10.5s would help some. We need Steve Kan to tune our cars

 

that is exactly what i told matty..... steve kan is coming for rotorfest on the 29th, he is gonna tune some cars..... can't wait to see a 25psi dyno sheet from my car

 

i havent doubted you bro..i put stock in what you say...i just need a kick in the *** sometimes.

 

Well, here is another foot kicking you in the ***....

Yes you need to be tuned, this is how I see it. Dave "tuned" your car up to 6800 so if he made changes it obviously needed the changes....so why wouldnt it need similar changes above 6800.....IT DOES, he's just scared to do it.

Sooo, here is my advice, get a ignition amp and install it the day before Steve tunes your car. Dont get under boost after installing the amp till Steve goes over everything cause if you happen to be border line a/f in some areas the amp can make you lean.

With borderline tuning your traps are great, especially with 60C ******* degree intake temps. **** man, I dont ever get on my car if they are out of the 40's. I'll tell ya this though I doubt your actual intake temps were 60C, you air temp sensor was prob just heatsoaked since its mounted in the uim. This will however throw your tuning all off since the PFC makes timing and fuel changes based off that sensor's readings.

You have a lot left in your car that can be accessed with realitivy little money (compared to a single turbos conversion) so I'd just keep what you have, add a amp and get Steve to tune it.

STEPHEN

 

Great....which amp? the msd is much cheaper no?

 

hks twinpower is expensive but you plug in and go no cutting nothing

 

Matty,
Your duty cycles WILL go up as the RPM rises, even if your throttle is relatively stable. This is because as the RPM goes up, the amount of time that the injectors have to fire in goes DOWN because the rotor is whooshing past even faster and faster. So the car has a very small amount of time in which to get the gas in there!

This is why you tend to notice your injectors are too small at 7000+ rpm, but not at 6000 or whatever.

On my car, when I first had the "XS Eng T04S Base Map" loaded in my PFC, my AFRS were mid-high 9s above 7000. That is so rich that it was losing power, stuttering, and just generally not feeling crisp and clean up to redline. I have removed quite a bit of gas and I am tuned at around low 11s at 1 Bar boost and the car pulls so nicely now all the way up to 8000. Very clean and smooth.

I recommend you get the AFRs checked with a good sensor (not one of those cheap 50 dollar add-ons to the stock O2 wire!) like you might find at a dyno. It doesn't cost that much, and wouldn't it be good to know where you stand?

Regards,
Brian

 

Matty,

I had the same problem as you had right after I got my car back from Dave in May. Car ran strong in low boost setting which was set at .92 ish... Then at high boost 1.06 it would break up around the same rpm as yours. Then I install the HKS twinpower, things smoothen out. I decided to have Steve Kan to retuned it anyways.
Steve took all the neg split out and in comparing the map from Dave, every cell on the map was rich, not too bad but can be better. Steve also smoothened things out at boost controller off (Profec B) which is set to 7psi. If you talk to Ihor on the forum, he will tell you the horror story about Dave's map on low boost. Good Luck, spend the $300 for Steve to take your 7 to its full potential.

Ken

 

thats what i am gonna do i guess. ALthough i cant take part in kans tuning for a little while...i have dumped alot of money into the car and need to wait alittle before i can spend 400 on an ignition and 300+ on tuning.

I was kinda of hoping that i could just add an ignition for the meantime ....you really think it is dangerous? will it really lean me out? I am running all 9s.
i am almost there...so close i can taste it!