KeithC2Turto

Again I have a Stratmoshere Adjustable CBV.

Just retested it. At the lightest setting it opens around 5 Hg, at tightest setting it opens at around 10Hg of vac.

Idle on my car is in the 9 to 10 Hg when warm

Thus, it idle it is possable that the vac signel would keep the valve open at most settings. As soon as the vac goes away the valve 'should' close.

Anyone know what the vac is at cruse?

Just reset it at is't lightest setting and turned the valve orintation so boost in the intercooler will betrying to push it open.

Also, when I put a mini vac gauge on it that the pistion did not move as smoothely as I expected it to. Also confirmed that the tip part of the valve that has the small vac/boost line hocked to it has a much biggger piston than the oppisite side. Maybe a 3 to 1 effective difference so I am not concerned about leakage when mounted this way on boost.


First impression is that it works pretty darn well at keeping the boost up between shifts.

If I recall right, even w sporty shifts at high rpms my boost would drop down to near .3 or .4 bar on the factory gauge and could count quickely to three befor the boost felt like it was tottaly back.

Now w my boost set a .9 bar, when I sport shift it at higher rpms I can keep my factory boost guage peged at .7 bar and the boost feels like it is back imediately.

I am not sure but I may have lost some low end boost. I will have to do a 3rd gear high load test from 2000rpms to tell for sure.

On a cool morning I remember seeing first boost near 2k and bosost building by 2.5k.

If I lost some early boost I may have to try increasing the spring tension and retest it.


Keith

KeithC2Turto

WOW!

First, I double checked and I still have my low end boost. I am gettint .7 bar by 2800rpms w first indication and around 1500 under load (brakes on to stall motor).

For me in my application reversing my CBV has made a big change.

As noted above, now when I sport shift at near 6k rpm my boost dose not drop below .7 bar. Used to drop to around .4 or .5 bar.

Also, if I cruse at 4000rpm I show .1 bar on the factory gauge. If I floor it it no longers goes to .3 bar , then .5 bar, then .5 bar.

Now it instantly goes to .7 bar in less than one sec!!!

Ya!

Thanks for the thread as it made me think about how these things work.

For comparsion my build is. stock turbo, 4 inch recored intercooler, SC cams, B&B headers, Borla muffler, Powerflow, custom fueler that instantly reduces control presure for faster metering plate movement & accel fuel, light weight flywheel, and EVC.

Keith

John McM

Just received the new OEM CBV, an exact replacement for the old one.

I cut the old one open and I can see why they fail so readily. As the cut away shows, the diaphagm edge is wedged into a join between the body and cap and therefore seems very susceptible to wear and tear when you consider the number of times it would open in everyday driving.



With the new CBV installed I can notice a real difference when coming off the throttle on boost; mainly in the form of a much slower decline on the OBC Bar readout and more boost being there when I nail the throttle again. Can't say I can hear the CBV working though.

69COU

Forge Motorsport FMDV007P
Fast Road Closed Loop Diverter Valve (piston)

Fitted last week nbut could not test drive due to crap weather.

Took the car for a test drive today now that all the snow has cleared up and the roads have dryed out.

Holds boost up at 0.7 in between shifts for immediate boost when changed up a gear.



Not very scientific but the car was running great this morning and remined me why i love it so much. Getting a feel for the new suspension setup as well also. Car is driving great.


Next little project ( I am going to fit the RS short shift kit)
Well i have the parts sitting in the garage.

Think i need to get under the car for this (Lowered this could be fun)
Trying to find out of i can get some wide car ramps somewhere as i dont like car up on jack. Where do you guys place your axle stands when jacking up???