Rb25 fueling.

[Clicky]

i have a series 1 rb25 into a s14. all stock except for a freddy intake and a boost controller. im running 11 psi
i just ran against a buddy who has a completely stock 2003 350z.
we were neck to neck. meaning, i wasn't pulling on him nor was he pulling on me. whoever had the jump stayed in the lead.
NOTE: i did have a passenger who weighs shy of 260 lbs.

for a while my car feels like its being forced. like its loosing power at top end. feels like i doesn't have that oomf that a rb25 should have. shouldn't i have beat him pretty easily since im running 11 psi?

i was thinking maybe my stock s14 pump isn't providing enough fuel. has anyone had a power difference when changing the pump?

I've changed:
MAF sensor
02 sensor
checked timing. although i think i did not set it up right since i didn't disconnect the tps.
anything else i should do? i believe a stock rb25 240sx should be running 13.5 quarter mile. am i correct?

[AS240]

You need to get a tuned for the increased boost. You're almost doubling stock boost. On my old rb25 @ 12psi, I pulled HARD on 03 350z, and if I ran a 350z HR from a 40mph roll, I would have about 4 lengths on it to the top of 4th gear.
On a mustang dyno, I made 315whp @ 12-14psi tuned on a SAFC2(intake, freddy plenum, fmic, 3" exhaust). I would say at a minimum, get a walbro 255. Even on stock boost, your fuel pump probably couldn't supply enough for that motor.
Bottom line, you need to get tuned. SAFC,AEM,PFC. Put the boost back down to stock until you can get a tune on it, because you are most likely running lean.
Btw, with that old setup, I ran a 13.0 at the track on bald tires spinning through 2nd. From a roll, I would pull on proven low 12 second cars.

Weren't my best runs of the night but the first was a 13.2 and second was a 13.4....spinning
https://www.youtube.com/watch?v=0uo0QcilqSM

[BigKriss]

"i was thinking maybe my stock s14 pump isn't providing enough fuel." :facepalm:

Your kidding, right ??:picardfp:

[supersayianjim]

and, your passenger is way too fat,loose them and the spare tire and you have some real weight reduction.

[spools420a]

your s14 stock pump is super maxed out dude,walbro 255lph will be perfect and cheap.also check for boost leaks while your at it.

[Clicky]

Hmmm my car seems really slow at stock boost.
And yea kinda was kidding. more like fishing for someone to tell me *no shit*

Haha anyways yea I know I had a fat dude with me but cmon. I should have still smoked him pretty bad.


Yea I just dont have the funds for a tune atm.
I was thinking about what fmu I should get? As of now I couod probably only afford a cheapy one.
Btw yo set timing it should be -5 0 5 10 15 20 right?
Cause Ive searched and theres different answers on where 0 tdc is.

[Kingtal0n]

The stock pump will not even suppose 180rwhp. I am surprised it even runs like that.

Furthermore, if it does run, then it should make more power. engines that run lean tend to produce more power because of the additional heat produced. They also tend to fragment the pistons, blow the headgasket, pit the head and deck, and can permanently ruin the engine.

I think you have more problems than just fuel- but start with fuel because that is perhaps the second most important thing... the first being clean oil.

[BoredEE]

Get a wideband, fix fueling issues

Then:

Get rid of the stock ECU, Nistune is the cheapest solution, but only get one if you know of a tuner that'll touch nistune.

[Clicky]

Yea I do believe I have more then a fueling issue. I turned the boost all the way down Till I get a walbro and pressure regulator. No wonder I couldnt boost passed 12 psi. Lol would start detonating hahahaha

How much would a nistune cost? Is it a programmable ecu? Motherboard?

[Kingtal0n]

I know people are going to come into this thread and tell you otherwise, however I feel it is my responsibility to alert you to this,

The factory RB25 engine you have there is not very stout. I would not change the computer, or upgrade anything on the engine for that matter. I have been able to destroy that engine with only 10-12psi from the OEM turbocharger in the past, several of them. The piston rings seem fragile, more than an SR20's rings for some reason.

I see you having low compression on several cylinders in the near future if you turn up the boost to anything more than 12psi, and having to replace the engine. And if you attempt a rebuild you will probably fail at it; these are just unfortunate facts from years of experience.

My advice is to leave the boost at 7-8psi and enjoy the car like that (with a proper fuel pump). If you want more than 8psi, that is, 12psi~ I recommend you upgrade your injectors, and go the SAFC route. Yes the SAFC is a band-aid and a "bad idea" In general, however, with only 12psi you should be safe, and furthermore it will save you the hassle/time/cost of going the stand-alone tuning route. If you retard the timing at the CAS about 2-3* and keep using only good 93 octane fuel the engine should survive for a while.

[Sforteen]

I know people are going to come into this thread and tell you otherwise, however I feel it is my responsibility to alert you to this,

The factory RB25 engine you have there is not very stout. I would not change the computer, or upgrade anything on the engine for that matter. I have been able to destroy that engine with only 10-12psi from the OEM turbocharger in the past, several of them. The piston rings seem fragile, more than an SR20's rings for some reason.

I see you having low compression on several cylinders in the near future if you turn up the boost to anything more than 12psi, and having to replace the engine. And if you attempt a rebuild you will probably fail at it; these are just unfortunate facts from years of experience.

My advice is to leave the boost at 7-8psi and enjoy the car like that (with a proper fuel pump). If you want more than 8psi, that is, 12psi~ I recommend you upgrade your injectors, and go the SAFC route. Yes the SAFC is a band-aid and a "bad idea" In general, however, with only 12psi you should be safe, and furthermore it will save you the hassle/time/cost of going the stand-alone tuning route. If you retard the timing at the CAS about 2-3* and keep using only good 93 octane fuel the engine should survive for a while.

Just curious, but do you always post completly useless and incorrect information?

people are going to say otherwise because you're 100% wrong. stop posting this non sense.

Stock Bottom end RB25's are known to hold 500whp without issue.

When they do fail, generally from a shitty tune or pushing the limits to far (600whp+) they don't break the actual piston rings, the pistons ringlands generally crack and it looses compression.

FYI, i pushed 12psi on a stock RB25 turbo with a Greddy intake and a FMIC thru STOCK S14 exhaust with a stock fuel pump, regulator and ECU. My car made 275whp and had a 11.7 AFR in boost.

[Sforteen]

The stock pump will not even suppose 180rwhp. I am surprised it even runs like that.

Furthermore, if it does run, then it should make more power. engines that run lean tend to produce more power because of the additional heat produced. They also tend to fragment the pistons, blow the headgasket, pit the head and deck, and can permanently ruin the engine.

I think you have more problems than just fuel- but start with fuel because that is perhaps the second most important thing... the first being clean oil.

I made 275whp on a stock OEM s14 pump, and stock rb25 fuel pressure regulator and ECU.

Engines that are lean, don't always make more power either.

[Sforteen]

These are just a few all stock bottom end RB25's, from 500whp to 700whp...

http://www.speedhunters.com/2011/11/car_feature_gt_gt_9_3_second_vc_commodore/

http://www.youtube.com/watch?v=RnsTW77tGdM

http://www.mercurymotorsport.com.au/2010/07/revenge-of-the-rb/

[Clicky]

Lol how would you know that I would fail at a rebuild? Lol useless post.

Anyways back to the topic.

Now ive double checked the ignition timing on it and its advanced at 23 degrees.
If I try to pushed anything past 12 psi the turbo starts popping. Like popcorn.

Now when I put the timing at 17 degrees it would start pinging at around 4k rpm with WOT At stock 7 psi boost.




Edit. Also at 23 degrees runs smoother than 17, which feels like its being held back
Idk what the F to do unless I tear it down which I really dont have the time to do

[BoredEE]

23degrees ignition timing?!?!??1

Base timing should be 15.

You are doing something wrong! Take a step back.

Download yourself a R33 service manual.

How are you picking up the timing signal?

[Clicky]

Picking up the timing signal with a timing gun.
Disconnected the tps.
Run a plug wire from the coil to the spark plug.

Car runs ok at 23 degrees. But feels weak after 5k rpm
Put it to 15 degrees and runs fine but feels reealllly slowww

[Clicky]

Bump somebody has to have info

[bboyclo]

Hit up Carl H for a rom tune, I personally don't have a rb25 I got a rb20. When in doubt about your fuel pump just change it out man.

[redline racer510]

You need a wideband

[Clicky]

Ok so I advanced the timing to maximum. I can spool passed 15 psi without detonation. For some reason I believe my ecu is pulling timing.

So ive decided to purchase an Emanage and just tune the sucker. F it.

Btw who is Carl H?

[bboyclo]

Ok so I advanced the timing to maximum. I can spool passed 15 psi without detonation. For some reason I believe my ecu is pulling timing.

So ive decided to purchase an Emanage and just tune the sucker. F it.

Btw who is Carl H?

Look him up he's pretty well known in the rb community he's on here and thats his user name

[Clicky]

Thanks bro. Will ask him a couple questions if he doesnt mind.