Forge RS in BOV mode: Part 1.....>
11-06-2005, 11:44 AM
#1
AudiWorld Uber User
Thread Starter
Forge RS in BOV mode: Part 1.....>
Well....Plugged the Forge in today to see what this BOV stuff is all about. Despite the Naysayers, it CAN be done with a few caveats to be discussed down the page a bit.
The RS set up in BOV mode:
<img src="http://images15.fotki.com/v246/photos/7/7305/2835485/DSC04143-vi.jpg">
Installed:
<img src="http://images12.fotki.com/v236/photos/7/7305/2835485/DSC04145-vi.jpg">
<img src="http://images12.fotki.com/v238/photos/7/7305/2835485/DSC04144-vi.jpg">
<img src="http://images12.fotki.com/v242/photos/7/7305/2835485/DSC04147-vi.jpg">
After installation, the car started and idled fine despite Tight's reported problems. I ran it with the soft spring and 2 turns up from the full soft adjustment. The RS has whats called a "Dual Piston". In the BOV mode you use the set-up on the left above. The Piston, has an additional release plate on a smaller spring. This serves to provide a seal on light throttle on/off where vacuum is moving the big piston, but opens hard on a full boost, high throttle lift-off. It also seems to help maintain idle as typical idle vacuum would lift the single piston off the seat unless set very hard. The smaller spring loaded sealing diaphram keeps it shut even if the large piston has moved a bit from vacuum. I think this design is the only one to work well in BOV mode on the 1.8T. The Forge also comes with a full compliment of adapters, pistons, plugs etc. so it can be set up in either Normal DV mode as well as BOV mode..Very tunable and configurable..And typical High quality that we're used to from Forge.
<img src="http://images12.fotki.com/v242/photos/7/7305/2835485/DSC04147-vi.jpg">
During normal driving, the car behaved perfectly normally. Very slight flutter on lift-off, but nothing to lead you to believe it was in BOV mode. On high boost and high RPM shifts the nature changes dramatically. Anything over 12 PSI resulted in a sharp Psssshhhh BOV sound. Very crisp and loud. Throughout the experimenting today the car ran great. Boost easily held to 24PSI. When on the gas in higher gears it was amusing to lift an get the BOV sound. After about 15 miles I came back in and checked block 32 of the adaptation levels. Sure enough, there was a slight increase in Rich correction (-2.5 and -5.5) so the car does indeed run a bit richer in this mode. I think some adjusting with the Adjustable FPR could bring this in line and provide the correction necessary for long term use thoug I'm not sure where it will settle in and in fact may not be an issue at all. Experimenting with the Valve in Single piston BOV mode was not very satisfactory and this is also how most any other "BOV" valve would work. It appears the dual piston design is really the key to satisfactory BOV mounting on the 1.8. No other valve that I'm aware of is set up quite like this. In Normal DV mode this valve works very well indeed. The lage chamber and revised and larger valve release spills air quickly without a lot of piston movement. Response is quick as a result. The Forge worked very well in both modes and as advertised. A few more experiments and tune tweaks to come...All in all, a very nice piece of gear and the only way to go if you contemplate trying BOV mode on your TT.
The RS set up in BOV mode:
<img src="http://images15.fotki.com/v246/photos/7/7305/2835485/DSC04143-vi.jpg">
Installed:
<img src="http://images12.fotki.com/v236/photos/7/7305/2835485/DSC04145-vi.jpg">
<img src="http://images12.fotki.com/v238/photos/7/7305/2835485/DSC04144-vi.jpg">
<img src="http://images12.fotki.com/v242/photos/7/7305/2835485/DSC04147-vi.jpg">
After installation, the car started and idled fine despite Tight's reported problems. I ran it with the soft spring and 2 turns up from the full soft adjustment. The RS has whats called a "Dual Piston". In the BOV mode you use the set-up on the left above. The Piston, has an additional release plate on a smaller spring. This serves to provide a seal on light throttle on/off where vacuum is moving the big piston, but opens hard on a full boost, high throttle lift-off. It also seems to help maintain idle as typical idle vacuum would lift the single piston off the seat unless set very hard. The smaller spring loaded sealing diaphram keeps it shut even if the large piston has moved a bit from vacuum. I think this design is the only one to work well in BOV mode on the 1.8T. The Forge also comes with a full compliment of adapters, pistons, plugs etc. so it can be set up in either Normal DV mode as well as BOV mode..Very tunable and configurable..And typical High quality that we're used to from Forge.
<img src="http://images12.fotki.com/v242/photos/7/7305/2835485/DSC04147-vi.jpg">
During normal driving, the car behaved perfectly normally. Very slight flutter on lift-off, but nothing to lead you to believe it was in BOV mode. On high boost and high RPM shifts the nature changes dramatically. Anything over 12 PSI resulted in a sharp Psssshhhh BOV sound. Very crisp and loud. Throughout the experimenting today the car ran great. Boost easily held to 24PSI. When on the gas in higher gears it was amusing to lift an get the BOV sound. After about 15 miles I came back in and checked block 32 of the adaptation levels. Sure enough, there was a slight increase in Rich correction (-2.5 and -5.5) so the car does indeed run a bit richer in this mode. I think some adjusting with the Adjustable FPR could bring this in line and provide the correction necessary for long term use thoug I'm not sure where it will settle in and in fact may not be an issue at all. Experimenting with the Valve in Single piston BOV mode was not very satisfactory and this is also how most any other "BOV" valve would work. It appears the dual piston design is really the key to satisfactory BOV mounting on the 1.8. No other valve that I'm aware of is set up quite like this. In Normal DV mode this valve works very well indeed. The lage chamber and revised and larger valve release spills air quickly without a lot of piston movement. Response is quick as a result. The Forge worked very well in both modes and as advertised. A few more experiments and tune tweaks to come...All in all, a very nice piece of gear and the only way to go if you contemplate trying BOV mode on your TT.
11-06-2005, 12:01 PM
#7
AudiWorld Uber User
Thread Starter
Yes but...>>
Depending where adaptation settles in it will be a slight bit rich as speculated. An adjustable FPR will allow you to tune this out somewhat though...But A/F ratios need to be checked and verified to be within range at WOT if this is done. So far, the rich correction is still well within desired adaptation ranges, so it may just be fine....