Black RX7. I still say your boost guage may be inacurate, or maybe theres a leak in the line somewhere. Is everything tight on the line? Try hooking the guage to something else.

If you are hitting fuel cut w/o the FCD then that means you are above stock levels. Depending on the car, usually fuel cut is around 8.6 psi but Im sure some can atest to different levels.

20 inches of vacum is a lot of vac. Not to say your motor isnt that strong, it could be but 20 is a lot for a rotary. i hear 20 is like a brand spankin new motor, not a rebuild. Sounds like you either have a really strong motor or a faulty autometer guage.

Again. Try tapping your finger on the guage. It sounds like your needle is sticking to me. Autometer guages are SOOO inacurate.

As for the restrictor pill, its not going to help you one bit if you have a fcd. The pill just restricts an ocassional spike in boost on a completely stock. Its kind of like a buffer for the boost reading and has no effect on performance. The pill is designed to keep fuel cut and compressor surge to a minimum. I wasted 15 bux shipped for the stupid piece of crap. You'd be better off getting that pos off a junk yard car, or just making your own out of a piece of plastic and a suing needle. (Heat the needle so it goes through the plastic. Thats all it is really.

 

well I'm sorry I lied earlier when I'm at idle it sits in between -20 and -15, I think I'm just going to get my self an mbc and be done with it

 

My fuel cut is ~ 8.6 PSI. I unplugged my FCD and drove around with it for a couple of days and I never hit fuel cut, but my boost didn't go above 8 PSI. I plugged the FCD back in for security purposes since I don't have a restrictor pill.
My car at idle pulls 12 inches of vac.

 

When i had that t2 man, It boosted 8 psi with stock dp and when i put that aftermarket one i had it 10psi but i was scared of that much psi and also it bothered me that smell. I remember that it idled at -17 also if you do get the downpipe you'll have some crazy boost spike if i remember corectly.

 

quick question if your still reading this, I'm planing on installing and s-afc, the older model with ****, then one I'm buying doesn't have a wiring aharness how hard will this be to hook up? Yes but weren't you using a boost controller?

 

well the new s-afc that i had was pretty easy to install. I took me maybe like 15-20 min. Tunning was pain in the a$$. I did use boost controller but i needed to turn the boost down, cause it was boosting 10psi and i was getting worried. I don't know much about the old s-afc but i think most of the wiring should be the same.
You should check the apexi web site and look at the manual, i don't think it should take you long.

 

I also have boost problems on my 90. You may want to replace all or most of your hoses. If I remove the IC and reinstall it i get perfect 18-19in/mer. But I only boost to 5 psi after the throttle plates. If I Tee into the vacume line right after the compressor I get 7 or 8 psi. Im assuming a line is leaking under boost. You may have the same problem. Dont forget the hoses are usually neglected and our cars are old and turbo<hot under the hood>. I think its a good investment to just replace every line all at once.

 

well i'm getting rid of the stock exhaust! Orderd the dual n1 Apexi cat back racing beat 3" down pipe and rx7.com test pipe. Has anyone built a front mount piping out of 2.5" J bends from hooker headers?? I found a sweet deal on a spearco core 18"x8"x3" brand new $525

 

NZ,
I found my restrictor pill right at the bottom of the boost sensor nipple. Would it make any difference if I took it out and put it closer to the manifold? The vac line goes from the boost sensor and T's to the BOV valve, then T's again to the boost gauge and finally goes to the manifold. Should I change the way this is run, or is this ok?

 

that is exactly how I have my setup

 

If your after market boost guage reads 5psi when you hit fuel cut then you either have a bad guage which is highly possible or you have the guage in the wrong place. Try relocating it. Mine is between the manifold and boost sensor before the restrictor pill and it reads fine.


You havent told me a reading after wacking the guage. Tap on it for me.

 

when I tap it it stay at 0, I haven't tryed tapping it will I'm boosting yet, yesterday I took out the crappy vac line (clear) that came with the boost gauge and put a real one in, same results, well I'm not sure excatly if I hit the boost cut at 5psi, because it jolted on the freeway when I was coming back from picking my car up, it did this when I droped it to 4th and tried to accelerat going about 60-70 mph, that scared the crap outa me so I slaped the fcd on and all was fine....so basically I havn't taken the fcd since I've had the aftermarket gauge.....is there a way to test the gauge with an air compressor?

 

Saabguy,
Which side of your boost line is your restrictor pill? Manifold or boost sensor? I can't tell by what you've said.

Like this:
Manifold, pill, boost gauge, boost sensor?
OR
Manifold, boost gauge, pill, boost sensor?

I also have to have the BOV line in there somewhere.........

Juat wondering if it matters where the pill is or not as long as it's there somewhere.

 

I've got the pill far after the aftermarket guage. The pill is 2 inches from the stock boost sensor.

The guage is tapped into that same line very close to the manifold.


I still say the pill is useless.

 

well I made my own restricer pill out of a small vaccum hose connecter, small enough to fit in the pressure sensor lines, I put it in mine which it was missing......no effect, so I said I'll go for broke and put one in the wastegate actuator line........no efffect, I think I have come to the conclusion the precat is extrremly cloged, should I gut it, I know I need a down pipe I just don't have the money for it right now, I guess it's fine for now, I'm not planning on taking it draging any time soon, so I guess this is "safe" for the time being, thanks for all the help

 

noooone carress. lalallala