Rb26 Gtr

[donkeypunch]

hey all,

as my previous post about plugs fouling etc, have LINK G4, no AFM's, -5's.... was trying to figure out why car running so bad till it warms up, hesitation/popping/backfiring

have figured out it starts backfiring only when making boost

any help would be great

cheers robbie

[DJMGTR]

Mine does that as well, think i just need a bit of a better cold start tune though. Only happens for the first 5 minutes of driving anyway.

I have a haltech e11, and apparently they are hard to get the cold start perfect.

[donkeypunch]

Mine does that as well, think i just need a bit of a better cold start tune though. Only happens for the first 5 minutes of driving anyway.

I have a haltech e11, and apparently they are hard to get the cold start perfect.

hey cheers for reply,

yeah apparently the cold start hasnt been set up on mine yet?

have been driving it around for last 3 months and has been sweet though, changed the plugs when they fouled and it worked mint, but then started running like crap about 50 km later, maybe running really rich and fouling when cold? i know my tune is set to run quite rich too?

[STATUS]

Mine does that as well, think i just need a bit of a better cold start tune though. Only happens for the first 5 minutes of driving anyway.

I have a haltech e11, and apparently they are hard to get the cold start perfect.

back fire during warm up is due to it being lean.

[donkeypunch]

back fire during warm up is due to it being lean.

hmmm wouldnt it have been doing this from day 1? its taken about 3 months to start the backfiring?

[(OO)SKYLINE(OO)]

Backfire is an explosion produced by a running internal combustion engine that occurs in the intake or exhaust system rather than inside the combustion chamber.

An explosion in the inlet manifold, carburetor/throttle body or air cleaner of an internal combustion engine will typically occur when the intake valves are not shut prior to fuel combustion.

The same term is used when unburned fuel or hydrocarbons are ignited somewhere in the exhaust system.

A visible flame may momentarily shoot out of the exhaust pipe.

Backfire in an automobile engine typically results from various malfunctions related to the air to fuel ratio.

Backfiring can occur in carbureted engines that are running lean where the air-fuel mixture has insufficient fuel and whenever the timing is too advanced.

As the engine runs leaner or if there is less time for the fuel to burn in the combustion chamber, there is a tendency for incomplete combustion.

The condition that causes this is a misfire.

The result of a misfire or incomplete combustion is that unburned fuel or flammable hydrocarbons are delivered to the exhaust manifold where it may ignite unpredictably.

Another backfire situation occurs when the engine is running rich (with excess fuel) and there is incomplete combustion during the Otto cycle, with similar results.

- http://en.wikipedia.org/wiki/Back-fire

Just did some Wiki reading for ya!

So it can be common for Turbo Charged cars, in your case, your R32 GTR having Twin Turbos.

My car sometimes gives a few "Pops" and "Pongs" with my high flow cat and standard catback exhaust.

[donkeypunch]

hey thanks for that

but when your car dosent almost get up a hill because of the backfiring when its cold when coming on boost seems to me a bit excessive, and considering it never did it before kinda frustrating aye

[(OO)SKYLINE(OO)]

^^ Yeah no worries!

Whats your turbo set up?... -5?

How much boost you running? I assume higher then standard with the -5's

You got an aftermarket ECU?... No AFM, are you running an APexi De-jetro?

Upgraded Injectors?

What Spark Plugs you got? You got the right Gap measurement?

[donkeypunch]

^^ Yeah no worries!

Whats your turbo set up?... -5?

How much boost you running? I assume higher then standard with the -5's

You got an aftermarket ECU?... No AFM, are you running an APexi De-jetro?

Upgraded Injectors?

What Spark Plugs you got? You got the right Gap measurement?

hey sorry 2860-5's, 15lbs low boost, 18 lbs high (about to go up to 22lbs) LINK G4, 770cc injectors, NGK 8mm gap

cheers

oh yeah, had the same problem before with standard turbos, power fc, AFM's, exhaust etc

both times car ran sweet, then as soon as i got it to queenstown where i live slowly started runnig like crap, fouling plugs?????????????????????????????????????????????

Edited May 19, 2009 by donkeypunch

[(OO)SKYLINE(OO)]

hey sorry 2860-5's, 15lbs low boost, 18 lbs high (about to go up to 22lbs) LINK G4, 770cc injectors, NGK 8mm gap

cheers

oh yeah, had the same problem before with standard turbos, power fc, AFM's, exhaust etc

both times car ran sweet, then as soon as i got it to queenstown where i live slowly started runnig like crap, fouling plugs?????????????????????????????????????????????

Ok...

Gee that's a fair bit of boost you running on low, just over 1 Bar and 1.2 Bar on high.

So LINK G4 is your ECU..? I am not familiar with that, just the standard ones and a few Japanese ones...

8mm gap... I can't remember what the standard gap is but I know that when you run high boost you need to gap the spark plugs wider... 8mm sounds wider than standard so should be ok...

770cc injectors!

Hows your fuel pump going? Standard or Aftermarket?

Have you dyno'd tuned your car?

[Beer Baron]

Ok...

Gee that's a fair bit of boost you running on low, just over 1 Bar and 1.2 Bar on high.

So LINK G4 is your ECU..? I am not familiar with that, just the standard ones and a few Japanese ones...

8mm gap... I can't remember what the standard gap is but I know that when you run high boost you need to gap the spark plugs wider... 8mm sounds wider than standard so should be ok...

770cc injectors!

Hows your fuel pump going? Standard or Aftermarket?

Have you dyno'd tuned your car?

no. when you run more boost generally you need to close down the spark gap. not make it wider. the standard gap is 1.1mm mate. and no 8mm will be out of this world. I think he means 0.8mm gap. no plug could give you an 8mm gap and no ignition system could give you a spark strong enough to jump that gap.

[(OO)SKYLINE(OO)]

no. when you run more boost generally you need to close down the spark gap. not make it wider. the standard gap is 1.1mm mate. and no 8mm will be out of this world. I think he means 0.8mm gap. no plug could give you an 8mm gap and no ignition system could give you a spark strong enough to jump that gap.

Ah ok smaller gap...

Thanks.

Yeah... Was just thinking that, 8mm is no way LOL!

0.8mm gap sounds right.

[donkeypunch]

hey there,

yes sorry .8mm gap, and yes have a nismo pump, and yes has been dynoed, my mechanic fixed problen it was the cold start not set up (i live in queenstown and was going to Aus for winter so it didnt get set up) and use 98 octane too

00skyline00 it runs the new LINK G4, its a new zealand company, been around for a while, robbie ward runs them too

cheers for your guys help

robbie

ps. its going back on the dyno tomorrow, cranking boost up too bout 22lbs

will let you know result tomorrow......

[(OO)SKYLINE(OO)]

hey there,

yes sorry .8mm gap, and yes have a nismo pump, and yes has been dynoed, my mechanic fixed problen it was the cold start not set up (i live in queenstown and was going to Aus for winter so it didnt get set up) and use 98 octane too

00skyline00 it runs the new LINK G4, its a new zealand company, been around for a while, robbie ward runs them too

cheers for your guys help

robbie

ps. its going back on the dyno tomorrow, cranking boost up too bout 22lbs

will let you know result tomorrow......

Yeah right!

LINK G4... Might just look into it for some info, thanks!

Good to hear you solved it. This was bit of a learning curve for me too. I wanted to find out and help you at the same time, but obviously it's a +1 for your mechanic. LOL!

Still good, now I know.

Yeah post dyno sheet up ASAP!

[donkeypunch]

Yeah right!

LINK G4... Might just look into it for some info, thanks!

Good to hear you solved it. This was bit of a learning curve for me too. I wanted to find out and help you at the same time, but obviously it's a +1 for your mechanic. LOL!

Still good, now I know.

Yeah post dyno sheet up ASAP!

sweet as....yeah should be interesting to see how much power comes out of it, those -5's feel pretty lazy on 18lbs, cant wait to up the boost!

[(OO)SKYLINE(OO)]

^^Lazy on 18 Psi... LOL!

That's high boost for you already, you want more?

Yeah why not..? Just up it that little more.

[donkeypunch]

^^Lazy on 18 Psi... LOL!

That's high boost for you already, you want more?

Yeah why not..? Just up it that little more.

yeah is kinda funney aye, i probably would have gone for the smaller -7 turbo's, i miss the low down pull of even the standard turbo's, i didnt really know much about tunning GTR's when i started.

but yeah (cue input from nismoid ) i think these turbos are probably a little big street use, because you have to wind them up to get the rush aye, i think 20lbs would be perfect though, will let ya know though.............

[(OO)SKYLINE(OO)]

yeah is kinda funney aye, i probably would have gone for the smaller -7 turbo's, i miss the low down pull of even the standard turbo's, i didnt really know much about tunning GTR's when i started.

but yeah (cue input from nismoid ) i think these turbos are probably a little big street use, because you have to wind them up to get the rush aye, i think 20lbs would be perfect though, will let ya know though.............

Yeah I was thinking that 20 Psi would be nice.

When does the boost start to kick in? What RPM and when does it hit Full Boost?

BTW Dyno sheet please...

[donkeypunch]

Yeah I was thinking that 20 Psi would be nice.

When does the boost start to kick in? What RPM and when does it hit Full Boost?

BTW Dyno sheet please...

i think its on full boost at 4800RPM, on 18lbs, it was tuned for torque not big horsepower, its sitting on dyno at the mo. standard cams, but with cam gears

[paulr33]

use the correction for water temp to richen the AFR's when the engine is cold (under 50 deg) and don't load the shit out of it when its cold (why would you?)

keep boost to a minimum when water temp is under 50deg (fairly obvious)