what do you guys think

[riverslide]

we turboed the car last thursday. it runs 7 to 8 pounds of boost. stock injectors, walbro, and vortech way to rich fmu (10:1). start the car in the morning runs fine for short drive. return to home let it set for 20-30 minutes get back in and starts to miss and splutter but will idle just fine.Has anyone had a problem like this, I just ordered the 7:1 disc for my fmu to see if the fmu is just loading the poor motor up and causing it to do this. The spark plugs by the way look decent not fouled. any help would be greatly appreciated.

[Chezedik]

We need more info. Maybe you have a dirty or fouled IACV.

[Florida240sx]

Where are oyu getting the A/F rati0o from? What kind fo wideband? Where is it at on your downpipe? What is your sparkplug gap?

[riverslide]

i'm confused by what the vortech fmu 10:1 actually means, i know that's not what the air/fuel ratio is (its gotta be worse ), no wideband, the spark plug gap itself is set at .030

[Chezedik]

10:1 means that for every pound of boost, the FMU closes the orifice and raises pressure 10 pounds. So if you have 7 psi, then your fuel pressure will be 70psi+43psi or 113 psi. This is why many people do not like them. But for a beginner it is fine for low boost.

[riverslide]

update:

we found 2 things that have contributed to my missing and spluttering issue. one, the t that i had used for the pcv valve was messing with the vent tube from the valvecover (to close together i guess). second, we have changed the fmu disc to a 7:1 and things run alot better. things are running fine now aside from an occasional intercooler pipe blowoff. we will be dynoing the car today to see just where everything is at. oh and for you guys in the dallas fortworth metroplex there is now a dyno here at one of the shops at motorsport ranch. thank you for all of ya'lls help, i love this site!

[KATwo40]

Glad you got it straightened out. Please, make sure you don't run more than about 7-8psi on that system. The injectors WILL get stuck shut because they cannot pull out of the pintle seat as a result of the incredibly high fuel pressure (100+psi is too much).

The reason Honda guys get away with this is that Honda injectors push downward off the pintle, rather than lift upward against the pressurized fuel.

[riverslide]

just got off the dyno roughly an hour ago.219hp @ 5500rpm257ft/lb @4400rpm11.7:1 a/f across the board@ 9lbs of boost on a GT25R

[Chezedik]

Try a little hairspray on the joints of your IC piping. It will help keep it from blowing off.

[Jookmasta]

post up ur dyno chart and congrats on the numbers. ur running stock timing? also whats ur gap set at? must feel nice to have no lag........

[riverslide]

gap right now is set at 35. stock timing yes. i had set the gap at 30 before and it retarded the timing a touch. but when trying to find my studder problem i changed the gap. i will get my dyno chart today. and try to post it. i'm still going to post pics of the car we just painted the roof last night.

[KATwo40]

Changing the gap does not retard timing, just so you know.

[emperor_lunchbox]

Riverslide:I am thinking about running an FMU. I was wondering what part you purchased to take your 10:1 FMU down to 7:1. Would a 8:1 be too rich.

I went to the vortech site and saw that they have a 7:1 recalibration disk for 7:1, but it says that this item is for use with cars that have 19 lb. injectors?Is that what you purchased?

also, what is your set up?

[riverslide]

i ordered the recalibration kit which consisted of a different disc and seat for the fmu. as for my set up it is as follows:

'95 kaGT25R Garrett Turboebay manifold and downpipevortech fmu now 7:1walbro 255greddy type s bov2.5" intercooler piping20x11x3" fmic