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-   -   Running without a DV- benefits other than noise..? (https://www.scoobynet.com/general-technical-10/757268-running-without-a-dv-benefits-other-than-noise.html)

t7srt 05 April 2009 06:54 PM

Been running No DV with a VF23 for 6 months now, 3 hard track days and all is fine, With the front mount there is a very load chirp much like the big powered cossies and gear changes are very direct,

Only down side seems to be on track where the wastegate doesnt know what to do on part throttle, other than that its much better than a dump valve,

slipstream_uk 05 April 2009 07:06 PM

Is it hard fact that the early VF's cant cope or is it just urban myth ?
Its not a dig at anyone, just trying to find out.

harrisard 05 April 2009 11:29 PM

hi ive got a 03 wrx still runnin standard turbo with i fink iz a td04 can these cope avin no dv?cheers

banny sti 06 April 2009 08:30 AM

Personally I would not run an early VF without a dv but its up to you if you want to risk it. A TD04 should be ok with no dv as the TDs are a lot stronger than the VFs

Banny

coops78 06 April 2009 09:03 AM


Originally Posted by banny sti (Post 8623492)
Personally I would not run an early VF without a dv but its up to you if you want to risk it. A TD04 should be ok with no dv as the TDs are a lot stronger than the VFs

Banny

Thats answered my question :thumb:

jasonius 06 April 2009 10:05 AM


Originally Posted by Puff The Magic Wagon! (Post 8621947)
My "blanking off" plate is a small length of "emergency hose" from Halfords and sink/washing machine waste pipe blank on the intake and a length of Samco and another on the i/cooler pipe :D

I did think of brass blanks but thought "weight saving" ;)

Can't beat a bit of plastic diy plumbing for weight saving..!:lol1:

Hadn't thought about those washing machine 'bung's, are those the ones that taper and about 3" in length..?

Once I'm certain I'm happy with no DV I've got some thin ally bar that I can Knock a plate out of. The intake end I hadn't thought about yet, but it looks like a trip to B&Q is in order..:D

Can anyone tell me what the internal diameter of the intake to DV hose is..?

New_scooby_04 06 April 2009 11:57 AM

I've been converted to running no DV. I was actually advised to by several highly regarded experts when going to the FMIC, but people considering it should be aware of one downside on maf based ECUs: it can make the car judder a bit when doing on and off throttle transitions. AFAIK this is because the maf registers air coming back the "wrong way over the sensor" and just erroneously adds fuel.

My squirrel blender sound is rather on the loud side as I have a FMIC and K&N cone filter; certainly gets the attention of people in the car ;)

For what it's worth, the advice I've always been given (again, by tuners and mappers) is VF30 onwards fine with no DV, earlier than that and you're risking it! Take it or leave it :)

chrisdicko 06 April 2009 12:38 PM

I've actually found my car is a LOT smoother with no DV compared to the BOV I was running. I am still running the MAF as well.

subaruturbo_18 06 April 2009 12:58 PM

What could I use with a phase two classic uk engine? Would I have to have a plate made up as the intercooler is different from the earlier classics?

Puff The Magic Wagon! 06 April 2009 01:23 PM


Originally Posted by jasonius (Post 8623603)
Can't beat a bit of plastic diy plumbing for weight saving..!:lol1:

Hadn't thought about those washing machine 'bung's, are those the ones that taper and about 3" in length..?

Once I'm certain I'm happy with no DV I've got some thin ally bar that I can Knock a plate out of. The intake end I hadn't thought about yet, but it looks like a trip to B&Q is in order..:D

Can anyone tell me what the internal diameter of the intake to DV hose is..?


BUNG!!!

New_scooby_04 06 April 2009 01:32 PM


Originally Posted by chrisdicko (Post 8623863)
I've actually found my car is a LOT smoother with no DV compared to the BOV I was running. I am still running the MAF as well.

VTA per chance? If so or with some aftermarket recirculating ones, that'll be why ;)

I went from the std recirculating one.

Ns04

jasonius 06 April 2009 02:50 PM


Originally Posted by Puff The Magic Wagon! (Post 8623966)

So I take it the oe hose is 32mm..?:wonder:

That will do very nicely..:cool: Just need a short piece of 32mm hose, as I don't want to cut original, just in case I decide change back at some time.

FWIW, after more evaluation today :D, the response after up-changes is much sharper. With slick changes the power is almost seamless with no appreciable dip, even when short shifting.

Looks like I'll be staying DV free..:)

Finally, I've not noticed any juddering (yet) and car does seem smoother, this was after removing OE DV BTW..;)

New_scooby_04 06 April 2009 02:54 PM

Litmus test: Motorway: 5th gear, get the car's boost building and at about 3.5k back off and see if you get some judder! :D

Davros 1979 06 April 2009 03:57 PM

Did you get anymore over boosting?


Originally Posted by jasonius (Post 8624147)
So I take it the oe hose is 32mm..?:wonder:

That will do very nicely..:cool: Just need a short piece of 32mm hose, as I don't want to cut original, just in case I decide change back at some time.

FWIW, after more evaluation today :D, the response after up-changes is much sharper. With slick changes the power is almost seamless with no appreciable dip, even when short shifting.

Looks like I'll be staying DV free..:)

Finally, I've not noticed any juddering (yet) and car does seem smoother, this was after removing OE DV BTW..;)


chrisdicko 06 April 2009 06:46 PM


Originally Posted by New_scooby_04 (Post 8623992)
VTA per chance? If so or with some aftermarket recirculating ones, that'll be why ;)

I went from the std recirculating one.

Ns04


Yep, was a VTA :)

jasonius 07 April 2009 11:10 AM


Originally Posted by Davros 1979 (Post 8624255)
Did you get anymore over boosting?

A little, but not what I'd call over boosting, just peaking a little higher longer..:norty: I'm going to try and get out today for a proper run down my local test route..;) I'll also try NS04's litmus test in 5th to see if there's any ruddering.

Will post back later..;)

joz8968 07 April 2009 11:22 AM


Originally Posted by jasonius (Post 8625871)
...to see if there's any ruddering

You wont need a car for that. ;)

jasonius 07 April 2009 11:33 AM

Highly regarded technical word is ruddering..:p

Sorry, I was replying to a post on xxx.net at the same time..:lol1:

chrisdicko 07 April 2009 12:49 PM

Here's a quick pic of the blanking plate I got made.

http://i16.photobucket.com/albums/b3...o/DSC00062.jpg

joz8968 07 April 2009 01:17 PM

chrisdicko, in addition to the two OEM bolts, did you also bond the plate to the flange by using some liquid metal glue too - for a perfect airtight seal?

jonny_693 07 April 2009 02:03 PM

I dont get it. Are you all saying no DV is better? That the DV does not stop the turbo stalling? Or is this just the placebo affect?

STiFreak 07 April 2009 02:14 PM

I may be wrong, but I assume that the benefit comes from not having to repressurise the intercooler pipework and core (this will be most apparent on cars with a FMIC). Yes the turbo would stall, but should get back up to speed very soon once you are back on the throttle.

New_scooby_04 07 April 2009 02:17 PM


Originally Posted by STiFreak (Post 8626307)
I may be wrong, but I assume that the benefit comes from not having to repressurise the intercooler pipework and core (this will be most apparent on cars with a FMIC). Yes the turbo would stall, but should get back up to speed very soon once you are back on the throttle.

That's what I was told If memory serves.

Ns04

StickyMicky 07 April 2009 02:26 PM

i ran an uprated recirc valve on mine, it was modified to give a higher clamping pressure and i would guess that at 90% of its life, it was shut, full boost/throttle changes would open it, the rest of the time it was clamped shut, and i suffered no ill effects.

joz8968 07 April 2009 03:20 PM


Originally Posted by StickyMicky (Post 8626342)
i ran an uprated recirc valve on mine, it was modified to give a higher clamping pressure and i would guess that at 90% of its life, it was shut, full boost/throttle changes would open it, the rest of the time it was clamped shut, and i suffered no ill effects.

Yeah, the above is probably a better solution...

When there's lots of really compressed, hot charged air between the DV and TB, then it'll be a bit kinder to the turbo thrust bearing/shaft, as the DV will actually open fully after those specific full boost/high load/WOT conditions.

jonny_693 07 April 2009 03:31 PM

Is it possible to put a stronger spring in the standard one? I have access to lots of springs at work? :norty:

New_scooby_04 07 April 2009 05:23 PM


Originally Posted by JONNY_693 (Post 8626474)
Is it possible to put a stronger spring in the standard one? I have access to lots of springs at work? :norty:

Zebedee? :Suspiciou :wonder:

http://www.cinema.com/trailers/wayto...ee1640x480.jpg

;) :D

jasonius 07 April 2009 05:47 PM

Tried the 5th gear test and no judder (or ruddering for that matter, lol..:D).

The car is much stronger through the gears, with instant power, not that I ever thought it wasn't previously, so quite impressed..!

The only thing that concerns me slightly is the peak boost of 1.7bar, up 0.1 on it's mapped target..! I've emailed Bob and awaiting his reply. As far as I'm concerned if the map needs tweaking then I'm prepared to have it done to ensure things remain safe. I've also noticed some surge (boost gauge fluttering a little) when going WOT mid-range in 4th and 5th. KL, so far has only shown greens once on a full bore up change.

NS04, I seem to remember you had surge issues, did this ever get fully resolved..?

New_scooby_04 07 April 2009 06:00 PM


Originally Posted by jasonius (Post 8626718)

NS04, I seem to remember you had surge issues, did this ever get fully resolved..?

Glad you're not getting judder......I wonder why? You're not using an aftermarket ECU or running a blow through maf are you?

Surge still there a bit on WOT sometimes in 5th, but that's due to the VF35 which is a "lively" turbo! :D

chrisdicko 07 April 2009 06:06 PM


Originally Posted by joz8968 (Post 8626171)
chrisdicko, in addition to the two OEM bolts, did you also bond the plate to the flange by using some liquid metal glue too - for a perfect airtight seal?

Joz, there is a small black gasket under there, which I think may keep it air tight.
Might try squiring some fairy liquid leak detecor on there to check though!! :lol1:


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