Hi guyz,
I heard every MCS '02 to 06', there is leaking bypass valve,

Is that true??!?!

 

not leaking...it just doesn't fully close


-and its not EVERY car, just most


I gained 2lbs of boost when I installed my Detriot Tuned BPV

 

DTBPV - the only way to go.

 

detriot tuned dpv?
what is that ?

Can we actually DIY ?

 

Is it possible that it starts to happen after 30k ??? And if so , does that result in slightly bad gas mileage ??

The reason why I am asking is because my gas mileage suddenly dropped and I heard that it might be the bypass valve .

Thanks .

 

Totally, I did the R&R myself.

Call, DT, they are a great help and have great insructions.

Get to it!

 

No. Your mileage might get better because you make less boost and consequently consume less fuel. The DT valve will give slightly worse mileage but provides other advantages wrt boost onset and the dreaded yoyo effect. I believe this to be a relatively simple DIY install.

 

in helix website i saw DT, is that replacement of the throttle body ???
Sorry, I'm not very good at engine .. :(
what does DT do ?

 

go to the vender list and click on "Detroit Tuned"

 

Can someone describe what exactly the "yo-yo" effect is?

 

boost drops off, lose boost

 

how does boost droping off produce a Yo Yo effect.

I'm relating a yo yo effect to an up and down or surging feeling of the car when holding the throttle at a partially open setting.

Would this be correct?

 

Yep

 

Interesting...I've wondered why my car does this. It is particularly annoying in second and 3rd gear around 3500 -4000 rpm's

 

My car yo-yos sometimes when it's between 5 and 10lbs of boost. Basically, the bpv butterfly is wavering between open and closed, and the boost gauge needle swings back and forth a few lbs. The vacuum diaphragm and the return spring in the bpv are having a tug-of-war with the butterfly. I don't really feel it too much in the car, but I can tell that the power delivery doesn't feel as smooth or strong when it's happening.

 

Actually my milage didn’t drop at all and may have been better as there simply was no real boost. Try this. Accelerate hard up to the redline. Do it where there is no one around and you have plenty of room and a shoulder on the road. If it goes to the redline fine you BPV is probably OK. If it all of a sudden shuts down and goes into limp mode, roll off and shut it off. It will be OK when you restart it but that is what Artoo did when the valve was bad. I couldn’t tell unless I was on it hard.

Rich

 

Vivi, the bypass valve allows a way to vent boost pressure from the intake tract. Improving overall gas mileage. As well preventing any over boost situation from damaging the engine. The throttle body is an entirely separate animal. Everyone says DT, because, Detroit tuned (DT) is the company that modified the stock bypass valve, to get the after market part that many install. And, I must add DT is an excellent company to order from.

 

This is probably THE most annoying issue on my GP!! 3/4 throttle in 3-4-5 gears. Vroooooooooooooom.........vrooo-ooo-ooooom.....vrrrroooooo-ooooo-oooooom

 

Yep. You've go.........Yo-Yo

 

Detroit Tuned rocks. I am planning on installing their valve on mine next week (hopefully!)

 

Made a HUGE difference for me ... I didn't have much Yo yo as i am usually WFO but it really did geve better biist . I run the BPV and the VGS mod together ... WOW !
I think I have a photo of my BPV ... i'll look

 

Or you can just adjust the limit screw on the stock bpv so it closes, put a restrictor in the vacuum line to it and even move the vacuum line to the same port as the fuel pressure regulator.

 

Yes a screw adjustment can sometimes be needed and if done fix the issue.
The Detroit cahnges the spring as well ant this gives boost "earlier"
The VGS mod (search it here) moves the origin of vaccum