MOD SHACK MOD: Boost improvements for $.16 cents (DV Tuning!).........>>
06-10-2002, 08:25 AM
#1
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MOD SHACK MOD: Boost improvements for $.16 cents (DV Tuning!).........>>
<center><img src="http://images.fotki.com/v5/photos/7/7305/112601/modshacklogoalt-vi.jpg"></center><p>
One of the things you discover as you add more mods and instrumentation to this car is sometimes things don't work the way you assume they should. Take Boost for instance. Adding the boost gauge gave me a window into how, when and how much boost was developing over a variety of condidtions. I was surprised how much throttle was required to put the car "on boost" and how soon boost dropped out with slight relaxation of the pedal. Hmmm....Maybe time to grease the DV (Forge 006, Green spring, aluminum, piston). Upon dissassembly everything looked fine. Began to think how and why the piston operates. Boost pressure bleed, spring tension and vacume affect whether the piston remains seated (and holds boost) or not (and bleeds boost). I figured increasing the spring tension would keep the valve seated longer. Off to Lowes for some washers (shims). I placed 2 washers (35mmx2.5mm) into the piston for a total of a 5mm shim, inserted the spring and bolted it back together. Guess what?
Boost now comes on with slight throttle tip in, holds longer, and is more linear in it's delivery. Not a bad improvement for 16 cents! One you can feel and see on the Gauge.
Here's the DV with shims (er....washers). Just slip them into the piston, insert spring, and bolt back together.
<img src="http://images.fotki.com/v3/photos/7/7305/119364/DSCF0103-vi.jpg?1023724992">
The washers fit the older Blue plastic piston as well:
<img src="http://images.fotki.com/v3/photos/7/7305/119364/DSCF0104-vi.jpg?1023725017">
Current set-up with APR Chip and FMIC is showing a peak of 18PSI (1.24 BAR) on the gauge. It pulls strongly into redline in every gear with no power drop-offs. All in all, a pretty good boost for the buck...
Steve<ul><li><a href="http://public.fotki.com/ttschwing/diverter_valve_stuff/">More DV stuff here</a></li></ul>
One of the things you discover as you add more mods and instrumentation to this car is sometimes things don't work the way you assume they should. Take Boost for instance. Adding the boost gauge gave me a window into how, when and how much boost was developing over a variety of condidtions. I was surprised how much throttle was required to put the car "on boost" and how soon boost dropped out with slight relaxation of the pedal. Hmmm....Maybe time to grease the DV (Forge 006, Green spring, aluminum, piston). Upon dissassembly everything looked fine. Began to think how and why the piston operates. Boost pressure bleed, spring tension and vacume affect whether the piston remains seated (and holds boost) or not (and bleeds boost). I figured increasing the spring tension would keep the valve seated longer. Off to Lowes for some washers (shims). I placed 2 washers (35mmx2.5mm) into the piston for a total of a 5mm shim, inserted the spring and bolted it back together. Guess what?
Boost now comes on with slight throttle tip in, holds longer, and is more linear in it's delivery. Not a bad improvement for 16 cents! One you can feel and see on the Gauge.
Here's the DV with shims (er....washers). Just slip them into the piston, insert spring, and bolt back together.
<img src="http://images.fotki.com/v3/photos/7/7305/119364/DSCF0103-vi.jpg?1023724992">
The washers fit the older Blue plastic piston as well:
<img src="http://images.fotki.com/v3/photos/7/7305/119364/DSCF0104-vi.jpg?1023725017">
Current set-up with APR Chip and FMIC is showing a peak of 18PSI (1.24 BAR) on the gauge. It pulls strongly into redline in every gear with no power drop-offs. All in all, a pretty good boost for the buck...
Steve<ul><li><a href="http://public.fotki.com/ttschwing/diverter_valve_stuff/">More DV stuff here</a></li></ul>
06-10-2002, 08:59 AM
#6
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Awesome steve.. Could you do some vag testing for the lazy people?`
Id love to see some data backing up your findings.. Should have never told people about this, you could have took another companys design, changed a thing or 2, add the spacers, call it a day and then market it as your own DV.. 
When you say power drop offs, are you talking about the boost drop at 6200ish rpms?? Im still running the stock chip and Ive noticed the boost drops off at 6200rpms (about).. It actually starts to increase at about 5800 then peaks, then at 61 or 6200rpms it drops big time..
When you say power drop offs, are you talking about the boost drop at 6200ish rpms?? Im still running the stock chip and Ive noticed the boost drops off at 6200rpms (about).. It actually starts to increase at about 5800 then peaks, then at 61 or 6200rpms it drops big time..
06-10-2002, 09:02 AM
#7
Wow, after MichaelTT's post ealier regarding his DV, and thoughts that mine might be sticking...
I'm off to get these washers, and dis-assemble my Forge.
I'll report back later.
I'll report back later.
