VR4 450cc injectors

[CLuTZ]

Hey guys i've got this new daily driver- '90 Galant GSR:

Rebuilt JDM 4G63T
Big 16g with new exhaust housing
GTpumps manifold
2.5" cooler plumbing with 600x300 cooler
3" all the way
Single board ECU (non eprom)
Walbro pump

Yesterday I fitted a turbotech boost controller, and dialled in 12psi. I took it for a blat, and sure enough it hit what felt like boost cut.

I know that its not actual boost pressure that sets off boost/fuel cut but mass air flow, but on 12 psi?

I removed the boost controller and it went back to the 9psi that it runs without any boost control. I did a 2nd gear pull and logged it earlier, and i'm getting 46 advanced timing @1800rpm, with 0 knock, and at 6700rpm its at 30 advanced with 1 count of knock, which to me sounds A.O.K.

What gets me a little alarmed is that the 450cc injectors are at 94.5% duty. On 9psi? The car goes REAL well, which has led me to think that when the engine was rebuilt, it had its compression raised.

I'm getting the car dyno'd tomorrow morning, so i'll have a graph i can share.

I know its a hard question to answer, but at around about what power do VR4 450cc injectors get maxed out at?

Is there something that i'm missing in this equation?

 

[matress]

with the bigger cooler pipes, intake, big 16g you'd be flowing a fair bit more air than stock... my car used to hit the boost cut at 14psi with stock intake, cooler pipes, cat back exhaust and big 16g front on a 14b turbo.

 

[CLuTZ]

yeah ok I can live with that, but 94% injector duty on 9psi?? :shock:

 

[DOUGMO]

yeah ok I can live with that, but 94% injector duty on 9psi?? :shock:

94% does seem a bit high,

is it running very rich?

does it still have a standard pump and regulator?

dirty injectors?

is the duty only that high at high revs or through
the midrange?

they are a few things to look at anyway

 

[CLuTZ]

yeah ok I can live with that, but 94% injector duty on 9psi?? :shock:

94% does seem a bit high,

is it running very rich?

does it still have a standard pump and regulator?

dirty injectors?

is the duty only that high at high revs or through
the midrange?

they are a few things to look at anyway

Its got a walbro pump with stock reg, that could possibly be it? false reading?

At 2000rpm the injector suty is at 10%. It steadily climbs through the rev range, hitting 40% at 3500rpm

 

[DOUGMO]

seems like it may be a false reading or its tripping out.

unless the injectors are working overtime because they
are dirty or there is a restriction up high,
its hard to say for sure

 

[CLuTZ]

seems like it may be a false reading or its tripping out.

unless the injectors are working overtime because they
are dirty or there is a restriction up high,
its hard to say for sure

Im planning to swap them out for some 560cc's anyway, so i'll keep an eye on it and keep you all posted

 

[Entaran]

Walbro overfuelling the stock reg.

Mine did. Fixed it with an SX reg

So much black smoke now gone. And it doesn't spit raw fuel out the exhaust pipe at idle. (Anyone got a gutted cat?)

 

[CLuTZ]

Walbro overfuelling the stock reg.

Mine did. Fixed it with an SX reg

So much black smoke now gone. And it doesn't spit raw fuel out the exhaust pipe at idle. (Anyone got a gutted cat?)

Surprisingly it doesnt run overly rich or blow copious amounts of black smoke out of the cannon.

I'm getting the AFR's checked with the dyno tomorrow- i'm trying to spend as less cash as possible on this car so if I can get away with the stock reg then i'll be happy.

If not, then my proposed stage 2 mods will include a sard fpr

 

[rob323]

It might be a bit late now, but pressurise the intake to check for leaks before you dyno it. I could be blowing a crap load of air out somewhere (eg. blow off valve) and dumping fuel in cause it thinks its doing the right thing.

 

[AUSVR4]

Yeah your problem is the stock FPR with the Walbro. Get the base fuel pressure back down again and it will run as rich as stock - but at least it won't hit fuel cut at 12psi!
Chip the thing!

 

[rob323]

chip chip chip chip chip chip chip chip :twisted:

My car with walbro and std fpr would hit fuel cut at 11psi. I then fixed all my leaks (bov and injector seals) and it would then hit fuel cut at 14 psi.
:?

 

[VR-4Squid]

hmm, odd - my jdm vr4 was hitting fuel cut at 16psi with Big16G, 450's, walbro, stock cooler/piping/inlet and 3" from the o2 housing.

 

[Entaran]

hmm, odd - my jdm vr4 was hitting fuel cut at 16psi with Big16G, 450's, walbro, stock cooler/piping/inlet and 3" from the o2 housing.

I cracked open my ecu and it doesn't look chipped at all.

Aspec with 070 16g, 650's, dual pumps, -12an fuel lines, FPR, jspec cooler w/custom pipework, bigger TB elbow, 3inch turboback, etc. No boost cut upto 1.8 bar so far. Might be chipped and I missed it... or it might be broken. heh.

 

[CLuTZ]

Okay well here goes~>


We got the car on the dyno and it hit 129.3kw @ 9psi. It felt alot more powerful than that, but I think its because i'm used to 4WD turbo, and not FWD.

We figured out that when I had it on 12psi, it probably wasnt hitting boost cut at all, it was possibly leaning out so hard it was fucking out due to not enough fuel.

What was disturbing was the fact that it is running so lean. Normally our cars run rich, and I would have thought it be even richer due to a larger fuel pump being fitted.

The richest point on the graph is 12.5:1, but it averaged around about 13.0:1, and on 9psi- there's something not right there.

I'm going to re-wire the fuel pump, and also change ECU/AFM/injectors so hopefully we can get it to run richer in order to screw some more boost into it so we can see some more power.

Any opinions are welcome


(graphs up as soon as my digi cam charges)

dre

 

[EVO85]

I was running 190KW's at the front wheels using the 450cc injectors (16psi) with similar mods + aftermarket computer. The injectors were totally maxed out at that stage.

 

[CLuTZ]

You can see the AFR's curving down nicely around the 115kph mark and then suddenly it decides to start running lean as all hell.....




I have a feeling that the fuel pump isnt getting its full voltage.

It could be causing un-usually low fuel pressure which is in turn making the injectors work harder to get the fuel into the cylinders, which in turn could be making it run lean on W.O.T??



thoughts??

 

[Entaran]

I think the pump's fucked.

Wanna walbro? I have one in my shed that slinkovic never got around to coming and picking up. Actually, I think it's at jerome's place... depends if slinkovic ever picked it up from there or not. Might still be there.

 

[CLuTZ]

I think the pump's fucked.

Wanna walbro? I have one in my shed that slinkovic never got around to coming and picking up. Actually, I think it's at jerome's place... depends if slinkovic ever picked it up from there or not. Might still be there.

I might take you up on the offer, but considering its got a walbro in it now, i'll see what voltage its reading before I make a decision wether or not to replace it.


thanks lorrie




dre

 

[Entaran]

If you want it, go and get it. You can sort me out later. I'm in no hurry.

The walbro at j's place is brand new still in packaging and a genuine one. Pull yours and see if it's one of those knockoffs, might be causing the issues.

My vr4 has a walbro in it and you can hear it about 3 metres away from the car. It's FUCKING LOUD.