Boost cut.

[Loofee95SE]

I'm trying to tune my car for this Friday Dyno schedule, ok not tune but trying to raise boost and have it stable all the way to red line. BUt I'm having problem with boost cut/ fuel cut. I've seen it run as high as .9 bar which is about 14 psi, and as low as.83 bar ( 12 psi). what give I'm just confuse about the situation. I'm not using the stock pressure regualtor at all ( u know the thingy by the ignitor). so what gives?? C

[Akihisa]

Do you have the stock ecu? If not than is the boost cut eliminated on your ecu. If it is just try running less gap on your plugs.

[Loofee95SE]

my gap is @ .7 mm right now cut from .9mm which is when i saw the .9 bar of boost, it seems like it got shorter.8 bar when i close the gap..I'll regap it to .8 mm tonight and see if I can see any difference. C

[pulsar gtr]

The humidity plays a good roll in the amount of boost. If it is very humid out there, you won't get the full boost as if you have a dry and lower temperature.

Do you know if both 12psi and 14psi were measured on the same day? Also, did you do any thing different before and after you measured 14psi?

Good luck,

RafiPULSAR GTR

[c-rad]

Keep in mind, if the temps drop, you will max out the maf quicker. Is it fuel cut or ignition break-up? Fuel cut is like hitting a brick wall, blowing out the spark will just create some studdering...

[capwred]

he also is running the stock maf like me.and im hittting 98, 99 % when i go to 13.5 psi with the smic.but he has a fmic if that helps.and he has the factory ecu with nothing done to it.

[float_6969]

with the FMIC, he's actually gonna max out the MAFS at a lower pressure than you running a SMIC. It's about the MASS of air, not the pressure.

[Loofee95SE]

good, then the Z32 I'm getting this Friday just before the dyno session should help. cos I can wire it up in a min. but yeah the amount of boost was done in 2 different days, because i had to order me a new set of plugs and wait for it after I install the BC. anyhow wish me luck for this Friday I'm hoping to make 200rwhp before the year is over with. mods : Sr T25 .80 a/r 3" test pipe and cat back Greddy FMIC Walbro 255 and Apex-i S-AFC II Power Enterprise hybrid Boost controller

C

[Loofee95SE]

well I finally got me a Z32 maf N60 from a Maxima doing the wiring on it right now, just waitting for a friend to get here with some pipes so that I can check it out..Hopefully this will solve my early boost cut and give me more boost so that I can hit that 200whp mark this Friday. wish me luck C

[float_6969]

good luck. let us know how it goes. Don't forget the dyno pics!

[Loofee95SE]

question to those that have Z32 maf and Apex-i SafcII. the air flow reading now read about 32% @ idle!!! when it was only reading about 2% with the stck CA maf..I have not yet to take it out for a drive, But it idle sooo Solid actaully idle beter than the the stockers. but I have the concern about the %tage..maybe I should take it out for a spin, just wanted to share...Happy thanks giving. C

[datsunboy]

thats because you dont have a Z32 MAF....Z32 MAF's are N62.....not N60.N60 MAF's flow around 320HP????....same as on RB20/25's

[r34 gtr]

my z32 maf (n62) reads about 0.5%-0.9% at idle depending on how the car is running/air temp/etc. im surprised that you actually managed to get the car running with that other maf! my z32 was a huge pain (partly because im not using the right connector).

i would love to go to the dyno with you guys tomorrow but i dont know if i can afford it just yet. which one are you going to, and what time are you planning on going?

- Tim

[Dattebayo]

You will be fine with the N60 mafs. Just make sure you have it in the SAFC as a Maxima/RB20-25 instead of a 300zx sensor. Thats why you are reading so high at idle...

It is the same one I have and plan to run! BTW, how much did you pay for your N60 MAFS?

Oh yeah, and 320 is exactly correct for its upper end.

Im sure that you can idle it at 32%, but if you punch the gas at all, your engine will just stumble and die. Change the data already!
Modified by 2BN_S13 at 8:43 PM 11/24/2005

[capwred]

r34, we are got to be there at noon for c's run and mario is going to run after him and then im going to dyno again.you should come down and just hang out.should be leaving his house around 11.

[Loofee95SE]

from 2nd test run: I install some colder plugs in and set my Safc to 4 7, and it now running perfect, idle perfect, running about 10.5 psi..didn't want to up it anymore until I get it on the dyno. THANK YOU GUYS VERY MUCH. hopefully I'll hit 200whp @ 1bar of boost tomorrow..Will report back tomorrow night. C
Modified by Loofee95SE at 9:12 PM 11/24/2005

[Loofee95SE]

Good news: I made 208whp and 198 tq, on 10 psi.which is my goal for this year.Bad news: I only enjoyed it for about 2 hours..I over reved the engine and now its sound like I have a handfull of sand in my engine...something on cylinder #1 gave out and it won't idle..car is parked...I'm sad, depress...need to take it apart and see what the @#$% I've done to my baby. I hate life..C

[float_6969]

That sucks. I'm sorry man!

[capwred]

well i dynoed mine with loofee and i only made 181 this time.the only thing that loofee has that i dont is a fmic and a maxima maf.so its time to order a fmic and fine a z32 maf.

[Dattebayo]

One of you guys should bolt on a KA sohc throttlebody and see what it does for your power... I'd be very interested in the results.

[float_6969]

I'm running one, but I'm not very close to stock either. I got 198rwhp @7psi.