Installed Forge replica bypass vale = lower boost!?

[quattrojan]

Hi. i own a 95 RS2 with mtm Stage 1 chip. Installed a boost gauge 2 weeks ago and that peaked 1.6/65 in 2.gear and 1.7 in 3, 4 & 5.gear.

Today i changed all the vacum lines and installed a Forge replice bypass valve but i was unsure on what spring i should use (came with 3 different) so being a man i put the stiffest in and mounted it and all looks good.

Then for the Testdrive.... i do get boost a bit earlier then before. But it wont go over 1.5 in 2.gear and it sometimes peaks to 1.6 in the remaing gears.. But i now i've got the good sound when u go of the throttle, not the ricerocket pppsssssssjjjjjj but the one one thats sounds like friggin bird but that tells me that the spring might be a bit stiff for the car cause isnt that the sound when the bypass doesn't open and the air goes back to the turbo? or am i wrong?

Anyways, would this stiff spring cause a lower boostpreasure?

Thanks

[lind4hl]

yep, to stiff spring so it "flutters" ( the air goes back thru the turbo and the turbine is chopping upp the sund)

Edit: but less boost i dont think, or Im tired

[GazzaG60]

i know of many who replaced forge and baileys as they leak over about 1.2bar

[Jonas_R]

i know of many who replaced forge and baileys as they leak over about 1.2bar

What did they replace them with?

[s2_bo]

Turbosmart valves dont leak, and they are adjustable too. Your replica valve most likely cant hold over 1.5 bar even with a stiff spring so its leaking everything over that I wouldn't push it to hard with that valve fitted or you might do the turbo some harm as its desperately trying to get you back to peak boost.

I would recommend fitting a proper valve and not using some cheap copy or low build quality valve.

[Rusty]

Spring has nothing to do with boost, only with idle and reaction on/off boost. Leak will cause boost fluttering. Put OE valve back in an retest. If it's still low then it's not the valve.

[quattrojan]

Found this one and might try it out http://www.hoppenmotorsport.com/bypass.htm

[Rusty]

Someone was selling a Dahlback Racing valve Skala or something like that. Contact him.

[s2_bo]

The spring does effect the boost imo, for example if you tighten the turbosmart valve right up it doesn't open at all until you lift off at around .5bar if its on the loses setting the piston is moving a lot more especially between -.2bar and .5bar. It may not effect peak boost but it does effect how boost is built up.

[Rusty]

Yes Bo, I agree. Once the boost is applied tho the boost holds the valve shut. The complaint here is peak boost tho. You should have the softest spring / setting that you can to prevent compressor stall (chirping).

[s2_bo]

Yeah thats correct, - I was thinking though, say if the valve didnt open till .3 or .5bar drop. Would throttle lift off at .2bar really do any damage to the turbo with the valve staying shut? Such a low amount of pressure wouldn't really create any compressor stall would it?

I have mine set like this, it saves the excessive noise around town

[EspenW]

Mount the valve in the reverse direction, with boost hitting the underside of the piston. Pretty much all diverters hold a lot more boost that way.

[Jonas_R]

I agree with Espen on this one at least when we talk about Forge valves. I have made a small test setup where I can simulate the same conditions as the DV experience when mounted on the car. And my Forge can handle 2 bars without leaking when mounted in reverse. But had to use gas tape on the screws that hold the two parts of the wastegate together.

Would like to get my hands on a APR R1 DV and try it out should be rather good.

However I have tried to mount a Bailey Motorsport DV30 in reverse direction, and this leaked like hell.

[GazzaG60]

turbosmart, blitz/hks and gfb were the usual better items depending on what a customer wanted.

[quattrojan]

Hi. I did some testing today and mounted the bypass in rewerse direction so the boost hits the underside of the piston. Also used a kinda sealant tape on the top and the other pipe just to make sure that doesnt leak.. Well.. not gettin over 1.5 no mather what now but it now sounds like it "flutters" just a tiny bit on max boost but i am having a hard time believing its leaking more now then before??

When i let of the throttle now i get a whole other sound, it kinda screams and a little bit of psssjj. I now got the medium strenght spring and i am wondering if i should try with the softest spring. Any ideas?

on the first run i had forgot to connect the the N75 valve and that as you all know results in veeeery low boost... but shouldn't it manage 0,5-0,6 bar even with the N75 unplugged? i remember id did that on my S6 but on the RS2 i never got more then 0,3 bar..

Thanks for any help