Atlmethevo

I had a Evo MBC installed and it spikes 23psi and tapers at 16 at 7500 and yes the boost gauge is good it was a dyno. I dont have it hooked upto the turbo but now everyone says it will fix the problem. Others say the 9 tapers hard no matter what. Any ideas?

03redtype-s

iTrader: (41)

do you have it ran to the turbo? If so then try hooking it through the bov. Cap off the turbo outlet nipple tap into the bov line nad run the other line to the wastegate. Seems like people have alot less taper issues that way.

Matt

tony gibson

iTrader: (1)

I actually had less taper going to the turbo on my Evo VIII....Then I got a forge bov and MBC (versus a dejon tool) and the fp wga and the car won't boost below 18psi! If you don't want boost taper get a bigger turbo lol...It is the only real solution because our high strung motor out runs the litttle 16g. An EBC would also fix the problem but then you don't have the nice low end torque spike....

Twisted IX

iTrader: (2)

I have the Hallman Pro Rx on mine and it is hooked up to the BOV line, the turbo side is capped. It is set @20 psi and I have ZERO taper to redline. Hope that helps.

Atlmethevo

I will try this, thanks guys.

tony gibson

iTrader: (1)

BTW the IXs tend to hold boost slightly better than VIIIs...especially MRs because of the metallic bov.

Warrtalon

iTrader: (6)

No, IXs don't hold boost better. In fact, they tend to taper more due to the MIVEC, and the MR is not any different. The JDM MR VIII had the metal BOV, which is why we called it the JDM MR DV, but now all the IXs have it regardless of trim.

Twisted, the Hallman Pro is great, but you do not hit 20psi and hold it flat to redline in every gear. That just simply is not possible, but many people like yourself love to say they "hold XX boost to redline" without every putting a MAP sensor on it to log the boost and see what it really does. Once you do that, you'll realize why saying such a thing is foolish, because you'll see that our boost has a constant drop after the initial spike. Lower boost like your 20psi won't taper as much as something like 23psi, because it's already closer to max efficiency and can keep up with the flow of the motor, but it still tapers nonetheless...

Atlmethevo, your taper does seem excessive, but it has nothing to do with your pressure source. It could be a boost leak or some other mechanical issue, so I'd check everything out thoroughly.