fuel cut.....with lex and 550's....

[gixxer750]

I just installed a lex replica from supra sport, presion turbo 550 cc injectors, and a walbro 255 in the tank. I'm still hitting fuel cut at 13 psi......? What the hell....

ooopsss.....I got a j tube to take off, gotta go!

I'm sure thats not the problem though....

 

[RacerXJ220]

Damn, I didn't hit my fuel cut with that setup until 28PSI. Is there a screw in the Lex replica? Perhaps take it all the way out? You also may have a boost leak. Too many things to tell.

The J-tube may be causing you to run rich rich rich, possibly too much to spark. Hope that helps.

Jeff

 

[mk3ukr]

I used to hit FC at 1.97bar boost pressure with Lexus/Riemer upgrade when my wastegate stuck closed.
It depends how much air you bypass through the unmetered chamber of AFM. I am sure you know this. Good write up is here http://www.suprasonic.org/public_html/lexusriemer/lexusnotes.html
Remove sealed factory adjustment screw of the AFM and fabricate your own. Use it to adjust fuel cut level
HTH
Vladimir, 89T

 

[Blue87T(Dan)]

I was under the impression that the Lex raised fuel cut to somewhere between 17 and 20 psi.

I have been kind of counting on fuel cut as a safety mechanism.

As for hitting it at 13 psi that seems strange. Is that with the stock turbo?

 

[MDCmotorsports]

Dan:
You're on a sp63 though aren't you?

The AFM's IIRC calculate FLOW not PRESSURE.

Also, sounds like you might have a boost leak some where....

 

[Blue87T(Dan)]

Dan:
You're on a sp63 though aren't you?

The AFM's IIRC calculate FLOW not PRESSURE.

Also, sounds like you might have a boost leak some where....

SP61GT actually, would the psi of fuel cut be increased or decreased with a larger turbo?

I realize I should know this but it is easier to ask.

I was basing my statement of 17-20 psi on a stock CT26.

Dan

 

[MDCmotorsports]

Dan, IIRC the psi goes down and flow goes up....

 

[GrimJack]

MDC is dead on the money. Pressure goes down and flow goes up with the SP61. By quite a bit, actually.

 

[gixxer750]

I'm running a 57 trim ct.... I got the supra sport replica housing that has the huge adjustment screw in it. the screw is turned all the way in. I drilled my j tube out now, but still have the problem. There is about half an inch gap in the bypass area with the screw all the way in. I guess I gotta adjust on it a little, but I still have no wideband.....

That could be a problem.

 

[RacerXJ220]

If you want to raise the fuel cut limit, you want the screw in there to be out, to allow maximum air to bypass.

Screw in lowers fuel cut. But it still should not be stikin 13PSI...

 

[thevork]

If you want to raise the fuel cut limit, you want the screw in there to be out, to allow maximum air to bypass.

Screw in lowers fuel cut. But it still should not be stikin 13PSI...

If the screw is in the whole way, it is possible that BC occurs before 13 PSI, because it will be just as restrictive as the original AFM.

Just take out the screw and the problem should be solved.

 

[gixxer750]

it should be nowhere near as restictive as the stock afm....its much larger inside.

 

[thevork]

it should be nowhere near as restictive as the stock afm....its much larger inside.

Well okay, maybe not just as restrictive, but as the mod relies on unmetered air entering your intake (and in this case it just doesn't) there should be no huge difference.

Correct me if i'm wrong.

 

[MKIIINA]

running 15-18psi daily on my lex and 550s with an sp61gt....hummm sounds like a hole somewhere...

 

[91T breezen']

I left the screw alone (about 1/2 way in) on my Lex. With stock injectors and a vfpr, happily boostin' about 14lbs on 92, all the way to 17lbs. with 110, fuel cut, no where in site!