Do most of you guys have a smooth vac to boost trans?

if not, what happens

For the most part I did. If it was at like -18 on the guage and I was just cruising and fucking stomped on it then sometimes there was a very slight hiccup on the 0 to pressure transition.

icic... You said did? You don’t have it anymore?

When you say hiccup, it’s like your turbo is spooling, and the motor isn’t going anywhere, right? Then it catches up to it self right?

I think I kina was experiencing that tonight. I drove it for the first time tonight (the motor was just re-built). Mind you I cant go over 3000 rpm cuz I have to break in the motor. But my turbo is spooled about 2100 rpm, and im cursing about 2,200 rpm, and just for a sec I would hit the gas down more and it wouldn’t really go anywhere, then I kinda felt it but I backed off because I didn’t wana boost on the new motor.

Does yours do that, say your going about 25 mph, and at really low rpm (about 2100 rpm) then hit the gas, it will kinda bog over and not go anywhere for a second? Or is this not normal?

but hey, thanks for the help! :thumbsup

I have smooth transitions. The only problem I have in the vac to boost transitions is during cooler weather, I might get fuel cut at 1 psi (I've yet to build the radioshack FCD), so a hiccup would occur. I haven't gotten any fuel cut so my motors happy. :) Unfortunately, I don't know how to fix your problem...

edit: so when you say "the motor catches on to it self," are you making boost? I can hear my turbo spool at like 1 vac-0 vac, and of course the motor is not making boosted power yet. Then at 1psi, you begin to feel a difference.




-------jezreel
1998 GS with hrc stage 2, sfmu, ml, prokits, egt, boost gauge, apexi tt, haydans tranny cooler, costum dp, dr. uber groundwires, dynotune fp gauge. gst muff, turbo spoiler
Boostin since Aug 03.

nothing like driving with the windows down and the music low: i love hearing the turbo spool, swwwhhhttt!!!!
thanks for www.kaptainmyke.com for the sig hosting :thumbsup

I have a missing link, and the vac to boost transition is perfectly seamless. I am having problems with my car sputtering at peak boost under WOT conditions...

I think I have the same problem... sometimes the car just rides fine and transitions into boost without a problem. Sometimes, right around 2000-2500rpm, I can hear the turbo start spooling but the car almost bogs down and feels like it has no power. Sometimes it almost hiccups and jerks. As soon as the car transitions into boost, the car regains all the power and drives fine. I see it usually happens when Im at low throttle, maybe under 25%. I had a missing link and I didnt notice the problem with the ML, but I sold that and got the Star FCD. The troubles started as soon as the FCD went in.

Im putting in an e-manage soon... hopefully thier built in FCD will solve the problem.

Originally posted by xtrickedeclipsex
icic... You said did? You don’t have it anymore?

She's no longer turbo.

Originally posted by xtrickedeclipsex
When you say hiccup, it’s like your turbo is spooling, and the motor isn’t going anywhere, right?

No, to me it felt like slight misfires.




Breaking in a motor with boost? :wary

Yes before I got the missing link I experienced this crap. Right when I hit 0 vac the car would fucking buck like a horse whenever I'd ease into boost. If I punched it then the car would run fine, it only hicupped when I eased into it.

When I ran the SFMU/missing link setup, transition was always seemless, and perfect. Now, what I think you are describing, is that at times, when you spool up the turbo a bit, you hear it spool, and see the pressure on your boost gauge, but the car doesnt really seem to go anywhere? I have had that same issue, but only on occasion, def not all the time..I believe its a fuel issue, and also an ECU issue. Just seems like the ECU is not suppling enough fuel at first. Most of the time, when building low boost, the ECU is still in closed loop, and even though we are raising fuel pressure though the injectors, the ECU is still controlling pulse width out of the injectors, and can be "laggy" at times. I don't think there really is a way around this, it just happens becuase all the conditons are present at that specific point in time, which explains this only happening occasionally. If we could make the ECU go into open loop control at the onset of boost, then that would be a good solution. Back when my HRC FCD went bad, i ran the car without any form of fuel cut control. Transition was still seemless, and never got fuel cut until i stepped on it, and was around the 4000-4500 rpm range..I don't get why it never got fuel cut at 0 psi, but it didn't :shrug

Yeah I think I have this problem too... Answers my thread in the MTX forum ... It must not be my clutch slipping!! :eek

yea im pretty sure it was a fuel issue for me to... We checked everything again and the breather valve on the fmu was open to much, so it wasent getting enough fuel...

why did you take the turbo off!!!??!?!?

Originally posted by xtrickedeclipsex
why did you take the turbo off!!!??!?!?

Becuase I went and bought this: