Rb25 S14 Advanced Timing

[Vq350z]

Hi everyone.

im coming to this forum in need of great assistance lol

ive been reading posts from all over the forums about rb's.

ive tried putting this question on Zilvia.net but no one could help

so here it is.

i have a 96 s14 with an Rb25det Series 1.

im using wiring specialties harness .

Freddy intake

FMIC

MBC.

Rb20 FLASHED ECU

now for some odd reason my car has poor performance at 15 degrees timing

it drives fine idles ok and there are no hickups to the powerband other than it being rediculously slow.

now i have fully advanced the timing and it runs OK. i can barely pull from my buddys stock 350z when im running 12psi.

at stock psi its still slow lol

things ive tried:

Checked timing belt at least 5 times to be sure it wasnt a tooth off.

replaced maf cause i had a bad one.

changed plugs gapped down to .26

waiting to try my buddys CAS so see if mine is f'd up

i havent had a chance to see if my ecu is pulling timing when high revving with a timing light

my main concern is why do i have to run fully advanced timing ?

btw at 15* if i try to run 12 psi it detonates like crazy.

there are no ecu codes

no vacuum leaks

no boost leaks.

my buddys stock 1jz s13 is way faster than my rb. wth

any help greaty appreciated

[jiffo]

Check knock sensor harness continuity.

What's happening with the VVT and the 20 ecu?

[blind_elk]

I think .26mm plug gap is WAAAAYYYY to small. Your engine should be capable of using near stock gap of 1.1mm. Maybe 1mm should be the least you would need.

Some timing lights give a reading double the actual timing. The safest way to get a proper timing is to use an old spark plug lead inserted between #1 coil and #1 spark plug, then set the timing "old school".

And was the ecu flashed on a dyno, or is it something someone says worked in another car?

[White GTS-T]

Surely he meant 26 thou? (.66mm)

[89CAL]

I think .26mm plug gap is WAAAAYYYY to small. Your engine should be capable of using near stock gap of 1.1mm. Maybe 1mm should be the least you would need.

Some timing lights give a reading double the actual timing. The safest way to get a proper timing is to use an old spark plug lead inserted between #1 coil and #1 spark plug, then set the timing "old school".

And was the ecu flashed on a dyno, or is it something someone says worked in another car?

These were pretty much my thoughts

You dont have the locator broken off the cam and have the CAS a tooth out?

The ECU was flashed to run 12psi? If it were me id get a 25 ECU and see if that improves things. Sounds like it would run better with a stock ECU anyway. Turn boost down to around 7psi

Edited April 5, 2015 by 89CAL

[Vq350z]

I've tried running with the stock ecu and it

Idles horribly rough to where it stalls.

But driving it on stock boost it feels Ok.

Yes that is how I checked timing.

I inserted a plug wire into coil #1 and set at 15* after disconnecting the tps

As far as the vvt I haven't checked anything for that yet.

This ecu is just flashed to run stock rb25 but I'm using a boost controller to creep the boost to 12 psi.

Yes I'm waiting to try another cas maybe tomorrow cause my buddy has an s2 rb25.

The harness continuity should be good since I'm using wiring specialties harness, but nevertheless thats not to say it can't be f*d up haha

Another thing I'm going to try is the knock sensors, maybe its sending a false signal to the ecu.

Compression ratios are

130

130

130

135

129

130

I don't remember if that was warmed up or not lol

[Got a Pulsar]

Blocked Cat?

[jiffo]

Wet or dry, those numbers are way low for stock engine/stock cams.

Never going to be startling off boost.

[GTSBoy]

What's happening with the VVT and the 20 ecu?

This! Latest Nistune stuff will allow RB20 ECU to run VCT, but as far as I know it is not possible to make it happen without Nistune. Ergo this RB25 is running without VCT. And that means that the fuel and timing maps both are not optimised in the half of the map where VCT is not working properly. Therefore it is not running "stock" maps in quite the way that it would run them if VCT was working. This might not explain all of this engine's problems, but it would certainly explain why it doesn't drive nice.

Edited April 6, 2015 by GTSBoy

[jiffo]

That's interesting about the newer Nistune. Did not know that.

I noted it ran OK with the stock ecu, just had poor idle.

Sometimes the front facing plenum install may not be the cleverest, often a cause of poor idle etc if the AAC circuitry isn't properly thought through.

[KiwiRS4T]

Replace the chip with a Nistune chip and get it tuned properly with VCT operating. Compressions are low but don't indicate any major fault.

[Clickyclick]

i have removed the Catalyst and im running a 3" straight pipe from the turbo back

yes it did run a little better then the rb20 ecu, sounded quieter and felt like a tab bit

more power.

then with the stock ecu i moved the timing to 15* and it ran super slow as hell and idles like shit.

my check engine light was even blinking lol i didnt even know it works lol

so only fully advanced does the car feel ok.

im going to try a CAS tomorrow

[Clickyclick]

i was thinking of getting emanage ultimate .

im hoping i could get rid of the problem with that.

but first i want to try to fix it myself haha

[ido09s]

don't buy something in an attempt to try to fix a problem until you have worked out what the problem is, its not worth the effort and it will more than likely end in tears