What's wrong with an atmospheric dump valve on a 2.3T? [Archive] - SaabCentral Forums

: What's wrong with an atmospheric dump valve on a 2.3T?


Obelix
15th August 2003, 01:45 PM
A few posts in these forums get me under the impression that atmospheric dump valves (aka blow-off valves) are not to be fitted to current Saab turbos.

I have a 2000 Aero and would like to know if this valve (or a similar one) can be fitted to my car:

http://www.forgemotorsport.co.uk/images/products/fmdv004.jpg

http://www.forgemotorsport.co.uk/saab.asp?cat=saab&product=FMDV004

murphwiz
15th August 2003, 01:56 PM
They can be fitted...

BUT will possibly cause long term engine damage...

T7, the cars computer uses an air mass meter to govern fuel mixture..
By venting to atmosphere, the air already metered and accounted for is lost, leaving the computer zlightly confused and having to alter its program, but its too late by this point, so the engine runs rich then lean...

You will get a check engine light within a short time, and it could lead to engine damage.

Eddie
18th August 2003, 07:48 AM
They can be fitted...

BUT will possibly cause long term engine damage...

T7, the cars computer uses an air mass meter to govern fuel mixture..
By venting to atmosphere, the air already metered and accounted for is lost, leaving the computer zlightly confused and having to alter its program, but its too late by this point, so the engine runs rich then lean...

You will get a check engine light within a short time, and it could lead to engine damage.

What happens if i was to fit this valve to my 1985 aero, would i still get engine damage in the long run??
regards Eddie

Matthew
18th August 2003, 08:24 AM
Excuse the imposter :wink:

T7, the cars computer uses an air mass meter to govern fuel mixture..
Didn't T5 see AMMs dropped in favour of MAP sensors? Or am I completely wrong :roll:

By venting to atmosphere...
Is the solution then to use a recirculating dump valve?

Alex
18th August 2003, 08:39 AM
T5 cars run with a MAP sensor, however T7 run with an AMM for emissions purposes.

Running an atmospheric dump valve does depend on the make and type. Both Forge and Bailey produce a dump valve that is designed for use on cars with an AMM and which don't open when at idle or cruise. The only time that the mixture is slightly affected is during gearchanges.

murphwiz
18th August 2003, 10:23 AM
Running an atmos dump valve on T7 will cause in the very least check engine light..

It is only recommended to run re-circ, Forge 007P fits and works fine.

XAAMOTTOMAAX
18th August 2003, 06:44 PM
Does anyone have any experience with Abbott's anodized recirculating dump valve? I just ordered one and was wondering if anyone had any pros/cons.

2000 9-5 Aero auto trans
Chipcenter Stage 1 ECM
JR Filter
just ordered and waiting on delivery...
Abbott high flow turbo delivery pipe
Abbott anodized recirculating dump valve

murphwiz
18th August 2003, 06:55 PM
Yes its fine..
made by Forge.. and cheaper from froge direct.

XAAMOTTOMAAX
18th August 2003, 08:08 PM
Looks cheaper at Abbott....
125.50 at ForgeMotorsport website
120 at Abbott
Are there any other products on Abbott's website that are just resold items from other manufacturers?

murphwiz
18th August 2003, 08:17 PM
is that Forge USA site?

Forge UK list at 80.50
http://www.forgemotorsport.co.uk/products.asp?cat=TUNDV&product=FMCL007P
Abbott list at 120
Both prices plus VAT @17.5%

PFS list it at 89.99 inc.
http://www.partsforsaabs.com/product_info.php?cPath=28_168&products_id=1128

XAAMOTTOMAAX
19th August 2003, 07:10 PM
So I'm getting the "stubby"?
Rats!

murphwiz
19th August 2003, 07:20 PM
The 007P is the only on that will fit in the space available! even more so with the larger diameter delivery pipe!