Help With Rb25

[copycutter]

Hey everyone, as the topic title suggests i'm having a few dramas with the rb.

Its kind of strange, because I initially thought it was boost cut. But i didnt think that r33 stock computer's cut at 10psi :S ?

Anyway the car only has a front mount, cat-back exhaust, a pod, and a plazmaman plenum.

I think the same spark plugs are in the car as was at the wreckers where i purchased the half cut.

Anyway, i've had the car at 11psi and when i try to bring the car onto boost in a tall gear like 4th, the car suddenly stops accelerating. Its like me hitting the brakes and brings you out of your seat. It was rough enough for me to think it was a boost cut.

But then after i've given the car to a mate to have the rocker covers removed and polished with fresh gaskets, as well as tidying up some of the brackets, hoses and fittings in the car (as well as fix a cut radiator hose which happened right as i parked it there ). Anyway when i drove it in 3rd at stcok 7psi and wind it right out it sorta sputtered a bit atabout 6500rpm, but it wasnt as rough i dont think. It was more like the misfiring my mate's r33 is notorious for. Then i tried turning the boost back up to 11 and winding out through 2nd, 3rd and 4th. It 'misfired' through 3rd heaps and 4th so i concluded i'd need some new copper 0.8mm NGK plugs which ill do this weekend and im wanting to nitto tape the coils but i have no idea how to.

When i try to build up 11 psi in 4th at night it does the 'hard cut' though...so im wondering if its a combination of boost cut and misfire

Is this sounding like the correct solution to this problem?

PS: I tried searching this sub forum but none of the thread's matched my specific problem and the sticky thread about fixing the coils with tape i couldnt understand.

Thanks, Nick

[benl1981]

See if you can borrow a mates PFC. SOunds like you are getting R&R (Rich and retard) due to increased ariflow. My car did this, looked into coils etc. As soon as PFC went in it ran the 10-11psi fine.

[paulr33]

it stock boost cut, turn the boost down, get a piggyback or stand alone ecu to fix it properly.

its actually excess airflow protection, it has nothing to do with boost and it's not based on PSI

[copycutter]

really? i thought r33 stock computers allowed more airflow (boost) than this before cutting. Ah well if its not misfire, then ill save for a pfc once i get my clutch and exhaust.

[copycutter]

Today I pulled out my spark plugs which seemed in good condition and replaced them with some NGK copper plugs at 1.1mm. Is this the correct gap level for the rb25, as i've read some of the spark plug threads and everyone was saying 0.8mm was more the go... I plan to get these copper ones changed every 5-10,000km which is easy enough. While I did this I also got some Nitto electrical tape and went over the whole head of the coil packs and cleaned them with a towel. I did it blind because I have absolutely no idea what I was supposed to tape up, so I taped the whole head of it up, as I assumed if the electricity was earthing out, it would do so on the metal plate that you screw the coils into....

I took it for a quick drive up and down the hill near my mates house to see if it still 'cut' at low rpm with higher boost - it still does so this means the car is hitting boost cut. The good news is that when I boot it throughout the rev-range now the car doesnt seem to misfire, and it might be my imagination but the car seems to pull a tad better in 2nd also.

Then i rectified the boost cut problem by turning the set level on channel 3 down to 10.0 psi and the car seems fine doing the "boost cut" test at about 2000rpm in 4th gear and booting it, and she didn't cut.

Now i'll just have to see if the cold nights make any difference, and then get off my lazy ass and set the gain and manual duty cycle levels for better boost control with the iD III, something again that i'll have to wing it on. B)

Edited February 24, 2006 by tuna_144

[BHDave]

the ebc you are running has a boost cut. check where it is set and what the gain reduction is at that point. it sounds like your problem

Edited February 24, 2006 by BHDave

[copycutter]

Hey everyone, just got back from nissansilvia.com Bayside Performance dyno day in Cleveland. My car was hitting boost cut in 3rd on the dyno at 10psi unfortunately so i had to turn it down to 9psi, and it made 146kw atw. It's a little under what I thought the car would make - as i've heard of completely stock r33's making about 150 ish, but most of the cars seemed about 10-15kw under what they should have been - like a 180 with a black top gt3040 powered sr20 on 1.5bar only made 224kw.

It also appeared to misfire a little again, and the guy operating the dyno asked me what plugs i was running. He told me that the 1.1mm was far too much gap for the rb, and i should be running colder plugs than standard - the '7' range. I think the copper ones i threw in yesterday were BCPR5ES11, so the 5 indicates they are on the more hot side of the standard 6 types i think. I'm gonna get a mechanic friend over and use my new feeler gauge to try re-gap these plugs to about 0.9mm and see if it helps - but the AFR's were crazy rich, and went off the charts at under 10:1

As for the boost controller, the blitz iD-iii i run has got 2 boost control features; auto and manual. Manual allows you to set the duty cycle of the turbo for better response. Since im lazy and havnt spent an afternoon hooning up and down a road testing the various duty cycles and gain levels i've opted to use the auto setting. I had it set at 11psi, then 10, and now 9psi because it was cutting on the dyno. But i think i've got the gain set at 0, because i also didnt know how to properly set it up...

Any inside info or advice anyone?