need help with tunning rb25

[BuH]

so im new to the nico forums so let me say hello guys. im from tampabay florida and a buddy told me about the site. ive been on trforums since 05 anyway the juicy stuff:

so ive swapped in an rb25det series 2 into a 93 s13 coupe. ive had problems with tunning since it was finished. just woundering what other people anr using for tunning. local shops have suggested an aem setup which is hella exspensive, an apexi fc power commander which is rare and still on the pricy side, and finnaly the greddy emanage ult which is cheaper but requires me to splice the harness. woundering if anyone knew of an easier solution than these three. maybe a plug and play harness that can be spliced to the greddy?

anyhelp would be appreciated thanks in advance.

[Cjmartz2k]

Welcome to Nico! First off, what do you want to do with the car? What kind of power goals do you have? I personaly HATE e-manage. It's a piggy back, not a stand alone. Think over priced SAFC with some features. Other than that, I'd go with what you can get tuned. I'm not the biggest fan of Power FC, but it's what people can tune here, so I've got one.

[johnny butt]

i am getting an apexi power fc from one of my friends around here locally he used for maybe 600 miles.

I am interested in seeing what #s I can put down with it.My setup:Mostly stock, 7PSI stock turbo, with HKS EVC6 boost controller/solenoid. FMIC, and Apexi Intake.

Nothing special, mostly stock, but I'm wondering what HP/TQ #s I should expect?

[Cjmartz2k]

Quit trying to OT one of the better intro/first posts I've ever seen on Nico, but low 300'ish rwhp with your mods and a good tune and upping the boost to 10-11psi. Oyeah, and assuming you have an RB25 but you didn't mention. Get on SkylinesAustralia.com and look at there dyno thread. Now quit thread jacking

[BuH]

thanks guys. i atleast expected one newb thrown out there... lol still tring to figure out the search features on the site im sure this has been discussed over 100 times. anyway my set up is simple for now. just 3" exhaust, blitz bov, nismo clutch, and FMIC. mainly my problem is when im coming to a stop i have to give it gas or the rpms fall down to fast and the car stalls. ive heard that i should switch to a " blow through" sytem instead of having my maf by the filter. ir the apexi or aem is the better choice do u guys have anysite where i might find a cheaper one. im lookin at over a grand for an apexi fc right now and i really dont want to drop that much.btw thanks for pointing me twords skylines australia. ill check it out. any help is appreciated

[240z4u]

Does that price include datalogit software @300? Thats the only way to really log. Tuning without it is all but impossible.

Evan

[Cjmartz2k]

If you are running an atmospherically dumped BOV, recirculate it back into the intake. That's why you are stalling.

[eh?]

With the pfc prices the way they are now I'd recommend the AEM. If you work out the prices for a pfc + z32maf + ebc + datalogit vs AEM + gm 3bar map + gm boost solenoid the prices will be very close. Also tuners are bound to be more experienced with the AEM vs a pfc....

[johnny butt]

hahahahaha, anyways, I think I answered the OPs question. (Plus, your BOV should probably be recirculated)

I said:I am getting an Apexi PFC [he is now looking at getting an Apexi PFC]

His next question would have been "here are my mods, what should I expect, here's a simple problem i am having" and guess what...

if you want to call me a "newb" go ahead, I guarantee I've changed out more bolts & parts on this POS 240 and RB25 than you could count.

Thirdly, You will need the datalogit box. Most shops will not touch it without it. Luckily, I have a local shop with it already, but I plan on getting it as well.

Once I purchase the datalogic box I am going to use the laptop that is stored underneath my seat with an S-video out to an In-dash 7" touchscreen monitor. Pretty simple (ballin') setup, especially for a "newb [like myself]." My laptop will probably be running Windows XP and I'll control the music from there as well and won't need to carry an MP3 player anymore.

Now suck my d!ck for answering the OPs questions before he even asked them. It wasn't a thread jack, it was an "i've seen this thread 20000x times, so here's the next part."

Anyways, OP- welcome to Nico. Good luck with your build.

[BuH]

thanks again for the advice. i didnt know the greddy needy so much more with it. from what ive seen many make it sound like it was self sufficient. and to jonny. i by no way was calling u a "newb" i was stating im surprised that no body called me one by only have 3 posts now. btw nice as hell set up. nico is by far the best forum ive seen. plan on being here awhile

also ive recirculated the bov and its still having the issue. its currently recirculated with the stock bov now. one thing ive noticed different from my build than others is i didnt get a walboro 255 fuel pump. i got a r33 gtst pump and it was installed in the s13 tank. could that be an issue? when purchasing it. i had read a few write ups that said it worked, now im just questioning my work is all. trouble shooting is always fun and im glad i have experienced people to turn to.

[johnny butt]

thanks again for the advice. i didnt know the greddy needy so much more with it. from what ive seen many make it sound like it was self sufficient. and to jonny. i by no way was calling u a "newb" i was stating im surprised that no body called me one by only have 3 posts now. btw nice as hell set up. nico is by far the best forum ive seen. plan on being here awhile

also ive recirculated the bov and its still having the issue. its currently recirculated with the stock bov now. one thing ive noticed different from my build than others is i didnt get a walboro 255 fuel pump. i got a r33 gtst pump and it was installed in the s13 tank. could that be an issue? when purchasing it. i had read a few write ups that said it worked, now im just questioning my work is all. trouble shooting is always fun and im glad i have experienced people to turn to.

It's cool, I wasn't taking a chance to attack you; everyone's pretty much here to gather research, socialize, and ask questions when need be, so it's not a problem. I just thought the other guy was being a d!ck since I was asking a pretty similar question with a similar setup as you --- I.E. What your goals on a "mostly stock" setup should be after a tune. I am tossing my **** together (ECU, new sensors, fixing my P/S, etc...) within the next few months and I will post up a dyno sheet / thread after my tune.

I doubt it's your R33 pump unless it's just a bad pump to begin with. Depending on age and condition, it could be. I went ahead and threw in a new 255 fuel pump because it was one less thing to worry about.

However, I'd check to make sure you don't have a leak in your intercooler piping or a vacuum leak anywhere else.

[scarboroughdub]

Im currently using a 300zx ecu from a 1991 twin turbo, it connects right to the rb harness and with a couple pin chages, it fires right up. Reason for using 300zx ecu is because it is chip tunable, rb25 is not as easy to tune.

Mind you the 300zx ecu now needs to be chip tuned to the rb motor.

Your other option is to use a rb20det ecu but it has no vtc control.

But your biggest criteria should be a tuner close to you and who is comfortable with a certain tuning system.



in this,

[Cjmartz2k]

LOL--settle down Johnny Butt. It looked to me like you did nothing more than post up your set up and ask how much hp you can expect to make. If you don't think so, fine, but don't get all rilled up about it.

BuH-as has been said above, the most important thing for somebody not shooting for rediculous hp numbers is how easy it will be for you to get it tuned. I'd find a shop where I could get it tuned first in your area and see what they can do/recomend and go from there. If you plan on 600+hp in the future though, you may want to be a bit more picky with what you get--i.e. I'm running into problems making my L-jetro Power FC work properly with a Z32 MAF in 100mm piping because I ran out of airflow on the standard Z32 MAF a long time ago. I wish I would have gone D-jetro 26 Power FC right off the bat.

There are some other EMS out there though like microtek, haltec, and vipec v44, etc. Those ones are kind of rare'ish though and it might be hard to find somebody to tune one. The 300zx ecu is also a good idea since, as has been mentioned, you can ROM tune it on the cheap and keep vtc. I think CarlH does ROM tunes. Ask him if he can do one with a 300zx ecu. That would probably be the cheapest option of all.

[meet07]

nistune looks pretty promising. I looked over the trial version last night and noticed that it accepts the ford maf sensors. One of them supports like 700 hp.

[johnny butt]

LOL--settle down Johnny Butt. It looked to me like you did nothing more than post up your set up and ask how much hp you can expect to make. If you don't think so, fine, but don't get all rilled up about it.

understandable. It was pertinent to his thread (My first three statements) and his initial question, however -- I just added an extra one so he'd know what to expect after tuning on a mostly stock setup.

Quote »BuH-as has been said above, the most important thing for somebody not shooting for rediculous hp numbers is how easy it will be for you to get it tuned. I'd find a shop where I could get it tuned first in your area and see what they can do/recomend and go from there. If you plan on 600+hp in the future though, you may want to be a bit more picky with what you get--i.e. I'm running into problems making my L-jetro Power FC work properly with a Z32 MAF in 100mm piping because I ran out of airflow on the standard Z32 MAF a long time ago. I wish I would have gone D-jetro 26 Power FC right off the bat. [/quote]So on a stock RB25, is the Z32 MAF going to be required? I have one I can pick up if necessary, but I don't feel like shelling out more $$ when I am picking up an "RB25 Apexi PFC" designed (and discontinued) for the RB25.

Or are you using the Z32 MAFS just for better airflow readings?

[240z4u]

So on a stock RB25, is the Z32 MAF going to be required? I have one I can pick up if necessary, but I don't feel like shelling out more $$ when I am picking up an "RB25 Apexi PFC" designed (and discontinued) for the RB25.

Or are you using the Z32 MAFS just for better airflow readings?

Its common knowledge that the RB25DET maf maxes out pretty early, I would just go ahead and do the z32 maf right off the bat and get it over with. I can almost promise you will need to at some point anyway.

[BuH]

good to know about the z32 maf. im going to look into running the 300zx rom tune more. this is news to me. if not ill have to give in and shell out the money for the apexi or aem unit. the problem with the rom tune is i dont know anyone local to florida that tunes rom tune. i remember hearing about it long ago, but its been years.

scarboroughdub- did u find a write up on the pin out for the 300zx or did u know somebody who did it? id be interested in that write up if u knew where to find it thanks.

[meet07]

http://ecu2.forumwise.com/ecu2-thread1825.html

R33 pin 19 to Z32 pin 34R33 pin 105 to Z32 pin 110R33 pin 110 to Z32 pin 105R33 pin 112 to Z32 pin 114R33 pin 114 to Z32 pin 112R33 pin 57: cutZ32 pins 29+55 : join (O2 sensor from R33 to single O2 input on R33)

ill spare u this time.

[Cjmartz2k]

So on a stock RB25, is the Z32 MAF going to be required? I have one I can pick up if necessary, but I don't feel like shelling out more $$ when I am picking up an "RB25 Apexi PFC" designed (and discontinued) for the RB25.

Or are you using the Z32 MAFS just for better airflow readings?

A single RB20/25 MAF is good for something like 300-350rwhp, and a Z32 MAF is good for around 500rwhp. Those numbers are just how much air it can measure before it maxes out at 5v. I ran out of flow on the Z32 a while ago. A Power FC gives you the option to simply select which MAF you are using (including a Q45 MAF).

You don't need to use a "bigger" MAF right now (they are the same physical size) with a stock turbo, but you might as well since it's so easy to do with a power FC. I don't know if the tune would need re-checking if you went from a RB25 MAF to a Z32 and just told the PFC which meter you had. I guess it would be fine though.

[BuH]

good to know. thanks meet. probably will still search for an apexi unit but intrigued by the 300 set up.

[zil40]

also ive recirculated the bov and its still having the issue. its currently recirculated with the stock bov now. one thing ive noticed different from my build than others is i didnt get a walboro 255 fuel pump. i got a r33 gtst pump and it was installed in the s13 tank. could that be an issue? when purchasing it. i had read a few write ups that said it worked, now im just questioning my work is all. trouble shooting is always fun and im glad i have experienced people to turn to.

if you're running the r33 pump you should run an adj. fuel pressure reg. to make sure your fuel pressure is stock. if not it could be rich, and causing it to stall.

[ANVIL]

A single RB20/25 MAF is good for something like 300-350rwhp, and a Z32 MAF is good for around 500rwhp. Those numbers are just how much air it can measure before it maxes out at 5v. I ran out of flow on the Z32 a while ago. A Power FC gives you the option to simply select which MAF you are using (including a Q45 MAF).

You don't need to use a "bigger" MAF right now (they are the same physical size) with a stock turbo, but you might as well since it's so easy to do with a power FC. I don't know if the tune would need re-checking if you went from a RB25 MAF to a Z32 and just told the PFC which meter you had. I guess it would be fine though.

damn, didnt know that about the stock rb25 mafs.... looks like to hit 400whp i need to get a new maf too... damn money pit

[BuH]

thanks zil40 and yes........ it is a money pit...lol