Engine Drivetrain 2nd Gen S Most liked posts in thread: Audi/VW Diverter Valve in a R56 S or JCW

It's not necessary to purchase a new OEM diverter valve for this modification, only the VAG unit, and at low on-line prices for the VAG piece it's a bargain compared to an alternative aftermarket Forge valve. The O-rings of a Forge diverter valve also must be lubricated at 10-15k mile intervals, no maintenance of the VAG/MINI hybrid is required. As an alternative, there may be an application where the all-metal body and stiffer spring of the Forge DV has an edge, as yet TBD.

The photos aren't working. Photos of this conversion are available here. The lower rear bolt can be seen by looking over the valve rearward. A magnetic wand will help retain bolts while removing, and right angle long needle nose pliers are good for inserting the bolts in the holes to start.

 

Great to know. I just ordered one along with 2 others from this town, so we did a 3-way split on the shipping and saved a bit. I thot the 3 bolts weren't that hard to take off. Any special tools req'd?

 

I've got a few of those valves, but the cost is the downer when you put the two together.

 

This mod is simply put Awesome. For some people it may be a disappointment though. Why? Because they will loose the nice hiss on release. It also smooths out the car so much that it almost seems like it is slower. I feel like the car lost power because it is less snappy but the power is still there, boost is higher and it is almost instant now.

A cool thing about it is how fast you can do it!

 

I only moved the intake. I didn't touch the coolant tank or the brake line.

 

Fixed the image. I made some changes to the site yesterday and I'm still working through a few issues.

 

I agree, smooth is quite fun!

 

I have noticed an big decrease in fuel efficiency since I did this. I swapped the original back in to see if my suspicions are founded.. More to come.

 

Ok, seems like my MPG is back up where it was before. I have had on the last 2 tanks about 7mpg less than with the stock DV.

Anyone want the VAG DV? I'll box it up and send it US flatrate for $60. Any takers?

 

Hey Dwight, I own one of the valves sold by Way. Much better then stock. Would I see an advantage here? and I'm assuming i could hybrid Way's unit rather then my stock one?



Sorry just realized you upgraded Way's unit and not the stock one...Thanks!

 

Boost does not equate to power in all cases. It has a proven leak in its closed position.The computer can control the waste gate to help build boost, but pressure is leaking back into the intake from the DV. Although it's beyond an efficient level for the boost being made, the top end power will stay the same as the turbo is being spooled and the target boost is met. Low-mid range power however suffers as it takes time for the turbo to basically over boost to over come the leak. As a result the car is actually slower and is why it feels smoother.

Several people have made post in similar threads confirming this. I even had it and can tell from first hand experience the car was not was strong. At first i was impressed as it did quiet things up a lil and shifts were smooth, but it didn't take long to notice the performance loss. I'd advise sticking with the JCW, 2010+ MCS, WMW DV ( all the same ) or get the Forge unit.

 

Quite the contradiction, the waste gate will ensure targets are met, but power suffers.

 

Only when thought of in such plain terms is it a contradiction. For any given boost level the turbo has an RPM level in which it hits what is considered the most efficient speed for that target. When all things are working right it should maintain its relative efficacy up to it's max efficiency rating.

Think of it like blowing into a drinking straw with the other end sealed. You will pressurize the straw pretty fast and with little effort. Now if that same straw had a pin hole in it what would happen when you blow on it? It would take more effort to bring it up to the same pressure level and maintain the level as the straw that is sealed completely.

In the the case of the VAG DV the leak is like the pin hole. It's not so great as to throw codes and such, but its large enough for the target boost level not to be met under normal conditions. The ECU will in turn close the waste gate off enough to spool the turbo faster to meet the goal it normally makes at lower speeds. This is like the extra effort needed to pressurize the straw with the hole.

What happens as a result is that the turbo basically ends up just pushing more hot air as it is spinning faster then it is required to under proper conditions to meet it's boost target. As most people know hot air is not known for helping build power. Also since it now takes longer to spin the turbo to it's new speed it will take longer to build power. Hence the loss of power from basically introducing turbo lag and increasing the temps of the intake charge. Now it is not a HUGE power loss but it is noticeable and can be felt. The feeling of this is actually what people believe to be redeeming qualities when in fact their car is just slower.

 

Thank you Grim for the thorough explanation. Now I understand. One thing I'm curious about, the WMW and JCW DV's basically have a stronger spring. What is the benefit of that, relative to how the car performs?