Hi all,

 

Got a bit of a problem with the revs dropping below idle speed when slowing down - especially from 50mph+ speeds. It sometimes picks up again but often stalls (most embarrassing!). I can often avoid the problem by changing down through the box as I'm slowing down.

 

This problem is definately worse since fitting Blitz BOVs on hardpipes. I'm pretty sure I've ruled ouut any chance of a leak. I've capped the points on the intake where the original recircs connected, capped the outlets from the recircs and connected my vacuum lines to the recirc vac lines. I've left the recirc vacuum connectors open - do these also need capping?? The BOVs seem to work ok but I'm not sure if they need adjusting (they're not hissing at idle) - second hand units so who knows what pressure they're set to!?!

 

I've used the shortest lengths of vacuum hose I could get away with without any kinks but I'm wondering if the additional hosing is a bit excessive along with a good couple of yards for the boost controller as well. Must be something vacuum related as use of brakes and clutch seems to make it worse/more likely to stall.

 

Car idles perfectly when stationary

 

Any suggestions would be greatly appreciated.

 

Best regards,

 

RobH

I've been looking at fuel controllers - Apexi S-AFC and HKS Super AFR and both make a big point of correcting the problem of BOV's on cars with hotwire MAF's when you back off the throttle.

 

I presume this is the norm when you change to BOV's.

 

I think it just proves that recirc valves are far better performance wise and is probably why no car manufacturer ever fits BOV's to their turbo cars!

I don't think any rally cars use them either - you can hear wastegates chattering but no DV whoooshes!

Got a new baby to play with now though - Honda CR500 to put on the road ;-)

RobH

 

 

You bloody nutter! Good on yer! :dance: :) MENTAL bikes those. I took one out for a 'spin' once and thought it was a bit slow for all the noise it was making. Then my mate pointed out to me that I had a 20 foot rooster tail out the back! LOL! :p When it hooked up properly it went like a bullet! Leaning over round bends makes you feel like you're falling off the side of the world! :cool:

Hi all,

 

Got a bit of a problem with the revs dropping below idle speed when slowing down - especially from 50mph+ speeds. It sometimes picks up again but often stalls (most embarrassing!). I can often avoid the problem by changing down through the box as I'm slowing down.

 

This problem is definately worse since fitting Blitz BOVs on hardpipes. I'm pretty sure I've ruled ouut any chance of a leak. I've capped the points on the intake where the original recircs connected, capped the outlets from the recircs and connected my vacuum lines to the recirc vac lines. I've left the recirc vacuum connectors open - do these also need capping?? The BOVs seem to work ok but I'm not sure if they need adjusting (they're not hissing at idle) - second hand units so who knows what pressure they're set to!?!

 

I've used the shortest lengths of vacuum hose I could get away with without any kinks but I'm wondering if the additional hosing is a bit excessive along with a good couple of yards for the boost controller as well. Must be something vacuum related as use of brakes and clutch seems to make it worse/more likely to stall.

 

Car idles perfectly when stationary

 

Any suggestions would be greatly appreciated.

 

Best regards,

 

RobH

 

Was talking to someone who had this problem on there Z,was found to be overfueling,the same happend at anything below 50 when slowing up.

 

Tony

Tony might be right... a previous engine was had this problem big time and it turns out it was running monster rich.

 

New engine had the problem to a lesser extent - improved it again by adjusting throttle cable.

 

Still had an occasional will-it-won't-it moment - but all the connectors on the idle unit were dicky. I would have replaced those next...

 

I rarely come to a complete stop in town anyway, so I only noticed this coming off short slip-roads. If you're braking hard often in traffic then you need to improve your driving not the car. :rofl:

I am leaning towards the idea that the car has and air leak somewhere on the intake system, since if you take the air filters out it runs even worse. soon as the filters go back in the idle stabilises.

I heard if you tape up the bottom of your induction kit it solves it! I think it was on TT net, (sounds like bloody stupid advice to me though!) mine had a similar problem, until I enclosed the induction in a chamber, seems to be fine now.

 

I originally thought it was to do with the BOV's and in some cases I guess it might be, but I tried fitting a friends re-crics and sill had the same issue. Now the induction has a pannel at the bottom of it and is partly boxed in (mainly because my weather guard was missing, and I didnt want water getting in there) it never happens.

 

Weird eh? if someone can explain the whole taping up jobbie or find the post that would be pretty cool, I can't seem to find it at the moment.

ere you go, knew I heard it somewhere;

 

http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=838040&words=stalling%2c%3a%3atape

Sorted this problem with my Apexi's just wound down the screw to the reccomended depth of 4mm and no more stalling.

 

2 min job :)

Hi, I did similar with my Blitz valves but I'm a bit concerned that they don't vent as much/as easily as they should...

 

Anyone know what the screw height should be for Blitz valves?

 

Cheers,

 

RobH

give Racelogic a call, they will be able to give you the specified height :)

I'm a bit concerned that they don't vent as much/as easily as they should...

 

 

Because you are screwing them down you are making the BOV release at a much higher pressure, therfore higher boost will be required for it to dump as much as it did before.

Hi Chris, that's exactly my point, all that nasty pressure stays in the circuit at low boost - can't be good for the tubs...

hi Rob this problem is old news to me. happened as soon as i fitted my apexis at the recircs. the more i rev the engine, the quicker the revs drop and more likely to stall. i believe in the over-fuelling problem more than the others. i even fitted an apexi SAFC2 but it didnt make a blind bit of difference :mad: :mad:

the only advice i can give is that when the car dumps, i tap the throttle a couple of times (in either D or N) and it pulls the revs back to idle.

Dave have you tightened the thread on the bovs ?

Chris i found that loosening them actually reduced the problem slightly - ie. dumped under less pressure and less aggressively and led to less drop in revs after dump (!?!?)

I'll try tightening them but my money is on a very loud TISH ( :hyper: ) and dashboard lighting up like a Christmas tree :rolleyes: