vacuum readings are these normal?
 

I just installed a VDO boost/vac gauge this weekend.

At idle I'm at 20mm of mercury on the vac side.
At easy accelleration I'm at 10mm of Hg.

Under boost I'm maxing at 6psi.

When I turn the car off the gauge returns to slightly below 0 psi.

The only hitch is that my AEM H20/Alc. injector controller is on the same line as the boost gauge.

I don't know if having the boost line "teed" and running about 12" of vac hose over to the injector controller would effect it so I thought I'd ask.

Next step will be diagnosing the seq. turbos.

boost not normal, vac normal :)

Sweet. I was hoping for a boost issue. Been feeling left out of all the turbo problem threads.

I think I'll probably just start fresh with new rats nest lines, check valves and check all the solenoids.

how is 20mm Hg of manifold vacuum (relative not absolute) normal?? Something's gotta be messed up with your gauge or with your car.. 20mm is less than one inch Hg of vacuum. 25.4mm per inch.

even if it was 200mm it would still be low unless you had a bridgeport. vacuum readings can vary a lot, but I can say that you're looking for a minimum of 250mm for a street ported engine--that's about 10 inches.

in/mercury. Gauge reads in/Hg, not mm. My typo

Stock engine, runs great otherwise, 40k miles.

Ha! huge difference. 20 inches is what I would expect from a healthy stock motor.

Now I just have to figure out why I'm only getting 6psi on primary. I think that is keeping secondary from coming on at all. Doing a lot of reading on vac hose replacement and turbo troubleshooting. Leaning towards the y-pipe coupler right now.

I can hear a rushing air noise when I boost. I first noticed it after I installed the HKS downpipe. Not sure if this could have anything to do with it but on my first drive since the DP and ever since I hear this noise once the boost builds. I asked the forum about the noise and everybody said it's normal to hear the turbos more without the precat but I think I'm hearing pressurized air leak as well.

boost leak tester for twins: http://www.fighters-garage.com/rx7.html scroll to the bottom

I have pretty much the same problem as adamrs. idles at 15mm, can roughly boost to 4 - 5lbs, but feels like very little power, just did block off plates and checked my vac lines, everything looked ok. Eliminated acv unit, split air pipes, double throttle, Isc, and aws tube. Helped with pressure a little but still runs the same when boost builds, can now boost to roughly 6-8 lbs but still very little power.Sounds like turbos are getting overworked. Here the same rushing air sound as well.

Mods are, dp exhaust with resonators, intake intercooler. How does the boost leak tester work?

It looks like the boost tester just pressurizes the turbo system and then I listen and look for leaks.

I'll probably go that route

Got a Mityvac silverline plus on the way so I can test all the checks and solenoids.

I did a full block off plate job and vac job along with daleclark check valves. Now I'm gonna chang my stock spipe out Last time I try spraying brake cleaner. On it while at idle. After spraying the brake cleaner the idle whould idle like shit for a few second. So I'm aiming to that. For
boost leak.

I just made my leak tester from a pvc cap and a valve stem, works like a charm and under 4 bucks haha.

What size of plumbing do I need?

Just measure the inside of your i/c piping cause mine is gonna be different cause I have a FMIC .

I'm thinking about cutting to the chase and just re-doing the rats nest, testing all solenoids, check valves, and get a silicone turbo hose kit. I would think this would cover it.

Wouldn't be a bad idea :)

how do you test the solenoids? And do you need a compressor to the boost leak tester? Could a faulty bov be part of the problem as well? I have a knock off one right now.

I'm pretty sure you'd need a compressor for the boost leak tester. It'll shoot air into the system then you try to figure out where it's leaking by listening or spraying carb cleaner.

you can try to access the leak visually without one but the stock vacuum stuff on these cars looks like a nightmare to me.

do a search. there are quite a few write ups on what tools are needed and exactly how to do it. you'll need a mityvac silverline plus. I just bought one for $70 off the internet.

I would use soapy water over carb cleaner. I don't think carb cleaner is what you need to use to find a leak. Also it's not good for paint, plastics and some rubber so I'd stay away from the carb cleaner for finding leaks.

back in business
 

The coupler from the y-pipe into the plastic intercooler entrance pipe was totally loose. The plastic pipe had popped off the coupler. I knew the air leaking noise was coming from somewhere. Now I'm getting 10-8-10. Sweetness again