I really like the VGS Mod. and the instant on boost that's possible. For me, treating the G pedal with finesse while being aware of RPM and selected gear puts me more in touch with my MCS. I find it's better to roll on the gas till I reach about 3,200-3,500 RPM before floor boarding it (saves tires some). It's still easy to modulate without going into boost or just controlling how much boost I want. I can take it up to red line without going on boost if I like.
Some of that awareness is also the audible feedback from the OBX header and MagnaFlow CAT back exhaust since I changed and quieted down the intake.
Logged 33,000+ miles with VGS and I'm not going back.

 

it's not a cheese grater!!!!!

 

you just went where i was dying to go but didn't have the heart. but seriously ;i've found that if you just run the i/c up and down your face for a while there's really no need to do your knuckles.

 

why knows why the cars respond differently, but that they do. I was swapping VGS/no VGS and modded BPV/Stock BPV. My car is definantly the best with both items on the car, without a doubt. But remember what they do:

VGS gets the vacuum from post SC. When the BP valve is closed, that means the VGS sees higher pressures so will open a bit later on lifting throttle, but as the valve opens, it will open REAL FAST as the higher pressure post SC is dumped back to the pre-SC intake..... When the BP valve is open, the vac levels are closer, and the BP valve will close at a sightly lower vacuum, but once again, posative feedback will accelerate the closing of the valve. FWIW, some turbo/sc tuning and building books actually have this as the "standard" routing, with what Mini gave us as abnormal.....
In the stock case, the pressure chages with motion of the BP valve fight the change..... Depending on tune and the drive by wire stuff, this leads to the yo-yo, but even if it's not present, it is a slower closing of the valve, delaying the onset of boost generation. But once closed, they don't make any difference, and you won't see any power differences, as both cases are identical.

The modding of the bypass valve affects the vac level (read throttle position) that the valve closes at. Stiffer spring needs more vac needs a more closed throttle. The spring constat tells you what vac level (if any) the valve will go to full open at. I think Andy Smith did measurements that showed the Ryephix II valve opened much at much higher vacuum, and never really got to full open. But once again, in a fully closed position, the stock and DT valve are the same (Assuming they close, that is) so you won't see any difference in peak power or torque.

Both of these work on the transition to boost, and you won't see much (maybe some shape changes down at 3000 RPM or so) difference in the dyno curve, and no difference in peak power or torque.

These two mods are independant, and while they may "talk to each other" via the drive by wire stuff that controls the throttle body, they do different things completely.

Hope this helps....

Matt

ps, when I went back to stock I hated it so much that it didn't last the week. Go figure! Maybe it's the ECU tune? I'm based on 39. something....

 

Yep. I like mine. VGS and adjusted OEM bypass valve.
I does take a while to get used to and throttle inputs needs to be better modulated.
Another thought too is that Johan for instance runs, I'm pretty sure, a higher boost level than I do. Based on how the bypass functions that may make the difference between acceptable and unacceptable behavior.

 

It made a huge difference with my car – prior to the vgs mod the car was a pig – now it runs nice and smooth, its been about a year and a half now without any problems

 

Dr Obnxs vbmenu_register("postmenu_1196702", true);
6th Gear
Join Date: Sep 2004
Location: Woodside, CA
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Gallery
To adjust the stop
just remove the valve, and turn the set screw. In later valves, they use some good thread lock, so you have to apply a little heat to get it to give.

To modify the spring, I took the diaphram apart, and then stretched the stocker. IT's not the same as the spring in the DT valve, but it gives you some of the effects (earlier closing, but it will open all the way, and doesn't slam closed as much under light throttle driving). Taking the diaphram apart is a bit of a pain, and having 3-4 small jewelers screwdrivers helps (flat blade, not Phillips!). I think the Yo-Yo Chronicals has info on this as well. But that is a novel of a thread!

The VGS won't trash the spring.... Vacuum is what fights to open the spring, and boost forces it more closed. Higher boost doesn't really move too much in the diaphram... Sound like his just gave it up, like many have before!

Matt
__________________
'02 CR/W S, Bunch of fun mods...
'65 Mustang Convertable, 5.0 EFI, 5-sp, 3.55 8.8", GR-350 Suspension, 271 WHP and a big effin' grin!


I must try it, Sunday

 

I have put it out.

Why?

At about 60mph cruising my accelerator was "dead" it was very slow. It's feel like turbo lag.
The OEM setup is much more responsive. And for hard driving the jerk at VGS was very anoying when let off accelerator.

Just for cruising it's OK but it's feel like the turbo lag. It's very easy mod so there is no problem if you do not like it.

Bye