RB25 ...HELP. HELP. BOOST ?'s

[96rbs14]

alight guys here's a quick rundown. rb25 s2, 96 s14, stock internals, stock turbo, stock everything except intercooler,piping, z32 maf, electronic boost controller (HKS EVC-S Boost Controller), timer. exhaust (apexi dual n1) APEXI AFC NEO air fuel tuner


ok my problem is i cant boost 13lbs without having some sort of cut out. not sure if its fuel, air, mixture, spark knock.... i have no clue.............

stock boost runs great, 10lbs runs like a champ, drives, idles, starts, cuts off like a damn new car, drive the car everyday but cant seem to boost over 11lbs without some kinda problem....

please help me, i want to see what she does on more boost...

thanks and any advice will be appreciated

[Sileighty_85]

does it misfire or fall on its face?

[96rbs14]

when driving normal on 10lbs or 6lbs it runs great man, when at 13lbs it acts like it stumbles a lot... then it will cut back down to about 11lbs,

i can be balls to the wall at 10-12lbs or so and it pulls like no other but when i set the boost controller at 13 or higher it jumps,jerks,stumbles how ever you want to call it, would love for someone on here to direct me the right way so i can feel the power of 15lbs...

hopefully im describing it correctly to help you solve my problem

[Sileighty_85]

sounds like a miss fire

What plugs and Gap are you running?

[96rbs14]

NGK BRK6E gapped at .025

[Sileighty_85]

Try opening them to .26 - .28

6's seem a little hot, I would drop it to a 7

[96rbs14]

You think that would make it hold more lbs of boost? I'll pull the plugs out tomorrow and switch to the 7's

Could it be anything else.

[Rabboni]

I think you might be blowing your spark out, so try what sileighty said. Anyways, What are your A/F ratios when it starts to cut? Have you tuned the ecu to run 13 psi, or did you just turn it up and hope for the best?

[!!chuy!!]

check your plugs...i was thinking it could be ur coilpacks but if your car runs like a champ at 10lbs then they should befine.....defenatly close the gap a bit or gett colder plugs

[96rbs14]

Never had it tuned, it's the wife dd and I get in and turn the boost up lol. 10lbs I can out run my 03 mustang gt with 315 rwhp. So it runs very strong on 10lbs boosts pretty quick. It's just around 12.5 13lbs it's like WTF. Lol. It would be a beast if I could run 14-15lbs when out running around on the weekends.

I'm not sure how to tune my air fuel apexi tuner?!?!?! It shows all the rpms and then Shows a table to set fuel hi and low throttle. Anyone have this kind of tuner and setup I have to help me tune for the better???

[redline racer510]

From what I hear and read 12 psi is pretty close to the stock rb25 turbo peak efficency range so pushing more boost on that turbo is going to create uneccesary heat and minimal hp and tq gain, maybe im wrong. As far as the hesitation, stumble symptom it is most likely what sileighty explained as spark blow-out, switch spark plugs and turn up the boost and keep us posted. BTW you might want to start thinking (and reading) about getting some kind of ems to tune for the higher boost.

[youradumb1]

go ngk 3330 stock gap...take the coil cover off..make sure your controller is working corectly...best way is run up the street with no hood so you can see if theres any boost leek near the syl..

[96rbs14]

ok its raining today and don't have the luxury of a garage yet, will change plugs but so far ive heard of two different plugs to choose from, which ones would be better for boost?

everyday driving with me which consists of boosting the turbo whenever i get the chance to, when i drive it the car stays roughly anywhere between 176-190 on sunny day around 80 degrees, before i had two e. fans the car ran 200+ on the days it was 95 outside so i know how it feels when you build up heat and it doesn't want to make the power it should, as of now it feels like when i turn up boost it turns up power like it should, as long as i don't turn it up past 13lbs

definately going to change the plugs but once again whats best for the rb?
this is my first import ive ever owned, don't hate me lol ive owned mustangs after mustangs, but i love this car like no other, jump in and go anywhere and outrun most on the way....

reason y i said this is my first b/c i have no clue about the tuning of my apexi, how to set my E. boost controller the correct way for 13lbs????
anyone with the same setup? if so please share the knowledge on how to set the controller the right way and the same for the apexi tuner....

REDLINE RACER 510---- what ems should i go with, without hurting my bank account, take in the fact im a newly wed, just bought a home, etc etc lol!!!

thanks guys for your advice, and not treating me like im some dumba*s.
please keep posting suggestions

[redline racer510]

Well in your current financial status I would just play it safe and run no more than 10 psi.When you do have money I would go with apexi power fc and take it to a reputable tuner or have steve shadows send you a base tune until you can get it tuned properly Just remember that there isn't too many options for tuning the rb25 exept for a a few like aem,apexi which are piggy-back units. Can anyone else chime in?

[Tenchuu]

http://i2.photobucket.com/albums/y19/Tenchuuk/1276042437696.gif
1. clean coilpacks and seal up gaps
2. gap plugs properly

now that that is out of the way... i notice that you didn't have an engine management. Mine went into rich and retarded mode where it missed and robbed me power when my manual boost gauge creeped up from 10 to around 12.

also from what i have read that 10-11 is max safe stock boost. any more than that causes undue wear and tear on turbo (ceramacis go boom) but this is just my reading of others opinions and experience. as soon as i turned it back down to 10ish, my car runs great again.

[OBEEWON]

Get that mess tuned ASAP. If you can get off the SAFC as well. If it is blowing spark out drop down to .22. Honestly it should not be blowing spark out at .25 though. I agree go to a colder plug as well. Also check your timing and make sure it is on point.

[96rbs14]

yea ive read that 10-12 is safe, but ive also heard of people running 14 on stock turbo all day long and didn't mention anything about a ems... my next big upgrade will be a ems then following that a q45 tbody and greddy intake.... but thats after christmas,

i cant tell yet if mine runs rich when above 12lbs, but like you said TENCHUU it acts like a tard and misses and almost any other car can come around me when hookin up

whats the ussual horsepower on a rb @10lbs, i have no clue on estimating power from the turbo... we have a decent dyno and a good tuner (from what ive heard of) in atl so hopefully i can get down there between now and christmas...

[Tenchuu]

Here are pics of a dyno day on mine at 6 and 10PSI. all i have is a pop filter, one piece driveshaft, OEM 300Z clutch on OEM flywheel, generic godspeed FMIC with leaks in the couplers and a turbo back exhaust with a test pipe.

http://i2.photobucket.com/albums/y19/Tenchuuk/car/dynoday002.jpg

http://i2.photobucket.com/albums/y19/Tenchuuk/car/dynoday001.jpg

as you can also see this was before i cleaned my coilpacks, the gaps are misses it was having.

Search Results (http://www.skylinesaustralia.com/forums/search.html&CODE=show&searchid=31507e28c6d80dc6be2cb673132c5aed&search_in=posts&result_type=topics&highlite=%2Bcoil+pack+fix)

i would highly suggest search here for more in depth answers. i con't find the link right off hand, but taking apart the coilpacks and cleaning the brass contacts between the pack and the boot, as well as cleaning the boot to plug contact and taping up the pacs works wonders for a high RMP miss.

[96rbs14]

man.... thanks you all are very helpful on trying to solve my dam* problem...

[Tenchuu]

just my opinion, but without a management option and tune i would only shoot for 10PSI. especially with a budget. it plays happy with the stock ecu at that level, and will be reliable for years. once boost gets turned up you run into issues of it blowing out the spark, but from what i have always read you end up hitting the stock ECU rich and retarded mode far before that, and i would put money that is what you are hitting. if that isn't what you are hititng a good cleanup of the coilpacks would probably let you hit it.

[96rbs14]

ok def. clean up coil packs this weekend, read over the posts and tell me which plugs are better for the rb25...ive had two different suggestions on plugs and gaps.....

[silviaSGP06]

RICH & RETARD!!!!! enough said.

Confused that you have come across the "14psi all day long stuff" and never come across the R&R stuff but its ok, the subject has not popped up in a long time even on the Nico rb section. People just say "go after market ecu!" without saying (or knowing) why.

The stock ecu isn't happy with stuff past 10psi, it sees a huge amount of air flow and thinks it needs to save you from overboosting. This is one of the stupidest things nissan has ever done and god knows why they did it on an RB ecu to begin with. It may have more to do with protecting the turbo more than the motor but w/e.
A SAFC may fix the issue at WOT but you may still encounter what your feeling at other load points aswell.

be happy at 10psi until you can afford something else. I have a PFC but if I had to do it again I would use Nistune on a re-pinned RB20 ecu

-Daryl

[Tenchuu]

RICH & RETARD!!!!! enough said.

Confused that you have come across the "14psi all day long stuff" and never come across the R&R stuff but its ok, the subject has not popped up in a long time even on the Nico rb section. People just say "go after market ecu!" without saying (or knowing) why.

The stock ecu isn't happy with stuff past 10psi, it sees a huge amount of air flow and thinks it needs to save you from overboosting. This is one of the stupidest things nissan has ever done and god knows why they did it on an RB ecu to begin with. It may have more to do with protecting the turbo more than the motor but w/e.
A SAFC may fix the issue at WOT but you may still encounter what your feeling at other load points aswell.

be happy at 10psi until you can afford something else. I have a PFC but if I had to do it again I would use Nistune on a re-pinned RB20 ecu

-Daryl

glad to see someone else knows about R&R on here.

why would you chose the RB20 ECU over a Z32 for nistune? i have been eyeballing these for a bit and it seems like the Z would be cheaper and come out the same in the end as you can pick them up from the junk yards here in US.

[96rbs14]

RICH & RETARD!!!!! enough said.

Confused that you have come across the "14psi all day long stuff" and never come across the R&R stuff but its ok, the subject has not popped up in a long time even on the Nico rb section. People just say "go after market ecu!" without saying (or knowing) why.

The stock ecu isn't happy with stuff past 10psi, it sees a huge amount of air flow and thinks it needs to save you from overboosting. This is one of the stupidest things nissan has ever done and god knows why they did it on an RB ecu to begin with. It may have more to do with protecting the turbo more than the motor but w/e.
A SAFC may fix the issue at WOT but you may still encounter what your feeling at other load points aswell.

be happy at 10psi until you can afford something else. I have a PFC but if I had to do it again I would use Nistune on a re-pinned RB20 ecu

-Daryl

Yea a buddy of mine had a similar setup with 6* timing and hit 13.7 all day long every time. He was puttin down 282 at the wheels.

Yea I'm def looking into a ecu. What do you think about a megasquirt? I know someone with a sr and he can run 14-16lbs daily or atleast that's what he's telling me.

Looking into a apexi fc. Just can't spend that kinda money any time soon. Would the megasquirt help until then? Could I resell the squirt ecu anywhere for what I paid for?

[sleeper108]

far less expensive than the A'Pexi unit, is the greddy e-manage. it's just a simple piggy back, but it will get the job done without hurting the bank as much. However it would be wise to upgrade at the first chance when you start doing a lot of mods to the engine

[96rbs14]

ok ill look more into the greddy unit tonight

[steve shadows]

AFC?

There is your problem

[redline racer510]

srry to thread jack but steve what kind of #'s have you seen on stock turbo with say fmic, exhaust just curious?

[steve shadows]

On stock RB25?

250 whp on stock boost with PFC installed on the Dyno Dynamics

we hit 300 WHp with a little bit more boost added a few times.

...now this was with PFC though....and also on a dyno that reads lowest in the industry...

The AFC really is a not a good choice imo because it obstructs your very critical MAF signal to the ECu and can Skew the way the ECU reads load and what amount of timing advance th ECu sends to the engine.

Timing is EVERYTHING in making good power, driving smooth and having linear efficient power delivery.

If it was me I would save up enough for a used PFC, or pick up the older Haltech E8 or E11 plug and play...

I know for a fact with stock turbos these motors can do 300 WHp on my dyno though...just need some direct EMS tuning with manipulation of the timing map directly...sometimes even 320...just depends if the turbo can handle it...

[Tenchuu]

I am feeling nice, so i put up a my own cleaning writeup based on the skylines aust one.

linky linky:
http://zilvia.net/f/tech-talk/354220-how-clean-rb25det-coilpacks.html#post3744157

[4-20sx]

yea i had that same problem with my SR. it was due to running rich and plugs werent gapped properly leading to "boost cutting".