yeah just wondering but I bought an autoguage boost guage, seems pretty acurate, reads 0 when car is off, -20 at idle, but I'm only seem 5-6 psi during full throttle, 1-2 gear only 5, 3-4-5, gears olny 6? WTF, the person who I bought the car from had an ACV-R and S-aFC, could this have screwed the ecu boost controller?? the wastgate spring is at 5.5 psi correct? should I just pay $30 for an mbc for the time being just so I can se 7-9 psi? check my mods in my sig, though without the FCD I hit the fuel cut, yes at 6 psi, don't understand maybe you do, any input is greatly appricaited

 

yes I have a pre-cat and no main cat, so I don't have a down pipe yet, but didn't the stock TII boost to 7-8 psi?

 

The S4 has no ECU-controlled boost control, it's purely mechanical. Max boost for as S4 is 6.5psi, but a stock car won't hold that to redline. I'd find out why you can't get stock boost first. I only have a pod filter and a cat back (no cats) and get 8psi. My bet is the pre-cat is clogged to hell. That's not right. Check to see if the restrictor pill is in the pressure sensor vac line. If it's missing you can hit fuel cut early. If it's there, I'd doubt the gauge.

 

I am in the same boat...I can only get 5-5.5 psi...I have 71k on my car, I just bought it last weekend, so I have some investigating to do...I am planning on putting a 3 inch DP and removing the cats...And Dynomax mufflers at the rear...Of course I will need the FCO hack and a better air filter too...

The mufflers on my car are even smaller than stock, so I think my lack of boost is due to the bottleneck there....

Stock boost is 6.8PSI....

 

where would the restricter pill be located? near the pressure sensore or closer to the engine?

 

not to mention I'm getting 180-220 miles per tank, I don't drive too crazy usally go to 6800 rpms 1 or 2 times a day at the most..........

 

What if the pill is not in the vac line? My car has silicone vac lines on it, and I don't believe the pill was put in. How do I go about finding one?

 

I have a full stock exhaust with a few leaks! I could not build more then 8 spi with a boost controller? so i pulled the vaccum line off the wastgate and pluged it! my T2 runs about 9.5 to 11 psi. I'm sure my cats are cloged up with 140K

 

Are you still running like this? If so, your motor will die soon. Start looking for another motor.

 

Isnt stock boost 5.5 psi?

 

It's at the manifold end of the line; mine was about 1.5" down the line. You can feel it by squeezing the line.

 

According to the FSM it’s 6.56psi, but a stock car won’t hold that to redline.

 

I just want to say to BlackRX7 that youve got awsome vacuum at idle. How many miles? Where does the car idle at? What does it pull if you are standing still, and you rev the car up to say like 3500 and then let off quick?

My car only pulls about 14-15 inches at 750 rpms.

Oh man!!! Try this. My autometer guage is a pos. I have to tap on it to get it more acurate because the needle sticks. Try that on yours!!

 

If you really want to test the boost guage and you really think its only displaying 6psi, then pull off your fcd and see if your car hits fuel cut.

Edit: Oh nevermind. you already said your car hits fuel cut if you unplug the fcd. Sounds like your autometer guage is sticking or just sucks.

 

I have a j-spec being built by pineapple Why is my motor going to die?

 

Its going to die from everything. You are prolly surging your turbo up the *** and overheating the intake temps higher than tollerable. Plus your original 140k miles means thin apex seals and most deffinately major turbo shaft play because of the miles and compressor surge.

Are you hitting fuel cut??

 

Okay! my car has 140k on the clock!! i dyno'd it @ 5psi 182.5 hp and 172 fp. the turbo is in great shap! NO shaft play, NO oil in the I\C and no smoke. The car has a blow off valve! and electric fan, water wetter,co2 intercooler sprayer. The seals seam fine? they hold boost.

 

Without any fuel mods, you must be running on the ragged edge of detonation. Many people have popped motors running that much boost of the stock fuel system, so a full-boost run on a hot day could be all it takes to kill yours. You have been warned.
To be only getting 11psi with no wastegate control means your cats must be plugged solid. You turbo and engine must be working incredibly hard to overcome this, meaning much more heat is being generated in the engine than is necessary (this will make the problem above even worse). Get those cats removed or replaced ASAP. And make sure you reconnect the wastegate first. One WOT run without it will probably see 16psi or more and will toast your engine.

 

Sorry i forgot to add i'm running 100 octain avation gas. I now every here on this board is vary helpful! I bought this car to drift,drag and rip the canyon! This is not my daily driver so i'm trying to have all the fun i can The car just isint fast @ stock boost.

 

My town is @ 5000 feet above sealevel witch is like running two or three less pounds then sealevel! Rx7.com web site states that 10psi is ok for the stock fuel system on pump gas

 

I have an autogauge and its pretty acurate when the car is off is sits right on 0,

Though I don't understand what your saying "what does it pull if...."
Awsome Vacuum? this motor has roughly 36k on it I bought it with a rebuilt engine, it idles after is warm right under 1k

 

Just checked no restricter pill at all, can you buy these at the autoparts store

 

If your gauge says 10psi, then that's what's in the engine, regardless of atmospheric pressure. Your turbo is just doing more work to get pressure up from the 12.2psi atmospheric pressure where you live than it would at sea level (14.7psi).