Recirc Dump Valves

[Adam K]

which one do people have and how much am i looking at for one??

i think atmospheric dump valves sound a bit barry and i don't really like creating loads of attention to myself. also my car runs like shít with an atmospheric valve for some reason, it's a rev1 tubby. any particular reason for this?

recently the current dump valve (an hks atmospheric valve) self destructed and i temporarily sealed the front of it so it can't vent air into the atmosphere. would this now be acting like a recirc valve or am i doing damage to the engine??

when i went on the rolling road my car was severely over fuelling, but i'm hoping all this is related.

[Stu8]

keep what you've got on then??

seems a waste of money buying somthing else.

I wouldn't seal the BOV up, because that air has got no where to travel and will cause damage to the engine/turbo due to back pressure.

however My HKS SSQV can be re connected back to the air intake, it still produces a slight noise. pointless doing really

[Adam K]

kept what you've got on then??

seems a waste of money buying somthing else.

it is broken, and i have just temporarily fixed it. i don't want a barry atmospheric valve anyway (even though this one doesn't make a noise anymore)!!

[midmotorsteve]

been doing LOADS of research on this the last couple of weeks going to all turbo car forums i can think off, overwhelming conclusion is go for the FORGE diaphragm racing recirc valve £110 + VAT and you may need a fitting kit £40+vat, but then as you already have an aftermarket valve you may already have one.

As far as blocking you've existing valve, that'll make it act like you don't have a DV at all so cause the turbo to stall after gear changes.

[Stu8]

I wouldn't seal the BOV up, because that air has got no where to travel and will cause damage to the engine/turbo due to back pressure.

sorry that only applies to the Rev 3 onwards, as they are usually connected to the intercooler intake pipe.

[Adam K]

i don't really understand what is being said in one of the stickys at the top of the page regarding atmospheric valves on rev1 and 2's........

is it saying that an atmospheric valve will make my car overfuel??

[Stu8]

only for 0.10 of a second.

honestly just put the standard system back on, if dont have one, I might sell mine to you, if it fit's a rev 1 that is.

[Bibbs]

if you want re-circ .. just get a Stock one .. HKS actually coppied it for their SSQV (and others).

[midmotorsteve]

I wouldn't seal the BOV up, because that air has got no where to travel and will cause damage to the engine/turbo due to back pressure.

sorry that only applies to the Rev 3 onwards, as they are usually connected to the intercooler intake pipe.

applies to all revs, they all have BOV on intercooler pipe :)

[KiwiMR2]

I second the factory bov idea......if you are happy without the noise then there is nothing better than the OEM unit :)

Cheers

KiwiMR2

[Jesus]

...except for it dumping ~100 degrees celcius air straight back into the air box!

[Bibbs]

...except for it dumping ~100 degrees celcius air straight back into the air box!

but when you have an AFM and are worried about the fueling issues .. what are you going to do?

[mattmr2]

Turbo Smart do a quite nice re-cuirc valve for the tubby - just another option....

[EarL]

Jim has an AFM on his (if I'm not mistaken, it's a rev 1 like mine), so how does he get around the issue?

[midmotorsteve]

...except for it dumping ~100 degrees celcius air straight back into the air box! 

but when you have an AFM and are worried about the fueling issues .. what are you going to do?

I've got this licked :) BOV after the Intercooler, my digging has found moving BOV to after intercooler is a standard mod on most ofther AFM cars inc Cossies, R5GTT's, All VAG 1.8T cars :)

[KiwiMR2]

...except for it dumping ~100 degrees celcius air straight back into the air box!

AFAIK when air is compressed, it does indeed increase the temperture (Its called "heat of compression) . But then it returns to the inlet side of the turbo (at atmospheric pressure) it loses the heat of compression. It is no longer compressed, so it is no longer hot.

Cheers

KiwiMR2

[Jimlad]

Jim has an AFM on his (if I'm not mistaken, it's a rev 1 like mine), so how does he get around the issue?

yip.. I have a rev with AFM and have had 2 different vent to atmosphere BOVs on my car with no issues.

Sure you can get the "stalling" problem etc, but you can actually rectify this by adjusting the preload on the BOV. It stalls because the BOV is actually sucking in a little bit of air. Adjust the pre-load spring and you can get rid of the problem all together.

I havn't experienced any other issues with having a BOV on a rev1 with AFM... the car runs fine.

[dj_davo]

but surely only cos of ur unichip jim?

[Jimlad]

Mmmm.... Maybe.

I dunno.

[KiwiMR2]

but surely only cos of ur unichip jim?

My old Gen I is running a turbosmart type one atmo bov & 13 psi....since around 127,000 km's to well over 200,000 km's today. No aftermarket ecu & no obvious issues :)

Cheers

KiwiMR2

[EarL]

but surely only cos of ur unichip jim? 

My old Gen I is running a turbosmart type one atmo bov & 13 psi....since around 127,000 km's to well over 200,000 km's today. No aftermarket ecu & no obvious issues :)

Cheers

KiwiMR2

That's what I wanted to hear guys. Thanks.

HKS SSQ here I come...

[Karma Supra]

I had an atmospheric on my supra TT. within 4 days I had taken it off, it caused the car to over fuel chronicly (washed bores hmmmmm) run like pooh, and sound like a chav mobile on steriods (it was sillily loud, *koff* bailey).

AS it was vacume operated there was a certain point (usually on the motorway) where I just have the throttle open a tiny bit, and the vac preasure caused the DV to stay open...... this totally confused the poor old AFM and mate the car splutter along when cruising on the motorway...

I'm suprised no one has mentioned the train of thought that no BOV is best!!!! its what the rally cars use... there isa theory that just before the compressers stall, there is a spike of boost, if you change throttle fast enough by the time you are back on the power the turbo has not stalled, but there is still a boost increase to "kickstart" progress in that gear....

Then again RAlly cars have sequential gearboxes, and probably get new turbos after every race :D

My Supra runs no BOV at all, (stock) but I'll be looking at adding a recirc one, as I indend to raise the boost!

P.S. any DV should be AFTER the intercooler!! so when you are on boost again the intercooler (large in vloume compared to hoses) does not have to "preasure up" again!!!!

[Jimlad]

Earl... just plop one on mate !

PS : Buy my Blitz DD BOV, I want a HKS SSQV !!!!!!!!!!!!!!!!!!!

[B7LER]

c`est...combien..?....Jimlad.................keyboard...is..knacked. :censor:

[Jimlad]

lmao...