ShopTalk Forums | Aircooled VW Tech & Restoration Help

I'm reading this from my phone, which may be the problem, but I can't see any images in your last post Baz.

They where there but either a huge resolution or silly size....

... and I'm meant to know what I'm doing

Hey Baz, I can see your diagrams now. The short answer to your question is, I have no real theory as to how the set up of your vac lines could improve your performance, except, the slight possibility that there were perhaps some air leaks in your old setup......?

bazibbo wrote:Well, I gave up with the tyres. sadly a little too big

For some time I've been scratching my head as to the physics around boost and how it effects me, the car and more importantly, how it fills pipes.

I've been changing the boost referencing lines around because I was concerned about the 'daisy chain' effect of hanging everything off one single referance point. (My wastegate referance line comes off the cool side of the turbo.) I've done a quick diagram to show what I've changed.

Before...



What is suprising, and the reason I'm talking about it, is that the car is noticably faster after the change!

Any ideas? My guess is that the dump valve can react faster, possibly letting the turbo spin up a bit quicker, making it feel faster. Seems odd though.... does pressure take time to build along a pipe?

Do you not have any kind of boost controller on there as well?

Is your blow off pulling its reference before or after the throttle plate?

On my old mexican setup i ran a line from the big port below the throttle body to the pressure pipe after the turbo. This smoothed out some major flat spots.

no boost control other than the wastegate Richie, that's referanced from the compressor. Certainly no bleed off or electronic thingy.

Chip, that's a point, as now I'm using both the outlets, big and small, after the throttle plate. With the dump valve coming off the larger outlet and the 'rest' being referenced by the smaller outlet.

Chip Birks wrote:On my old mexican setup i ran a line from the big port below the throttle body to the pressure pipe after the turbo. This smoothed out some major flat spots.

Is that a line to the dump valve (in the pressure pipe after the turbo) or simply a kind of bleed / balance pipe between the two?

I'll take a closer look at my outlets tonight.. think there's 3 under the throttle plate... dunno.

I just used the big one as a balance pipe. If you look inside the tb, there is a hole that the butterfly sweeps over in the funky bend. This is attached to the big outlet. So it is not actually under the throttle plate. Kind of in the middle of it. I would connect the dump valve to one of the other two.

Ah.... I'm a liar

In the cold light of day I'm plumbed up slightly differently - not massively differently though...



Front on. You can see the big alloy spacer that's different from the original. Would this block the inner channels? I should really pull it apart and have a look.




Side view. You can see that I'm using the outer two outlet/ports. I'm describing the top, outer most outlet as 'the big one', though thinking about it, I think might have used a big pipe on a small outlet (confusion) but you can see what goes where now.




Close up on all 3 outlets / ports.

I've looked and I've plumbed the lower outlet to the dump valve, the top one heads off to the ECU, FPR and boost gauge.
The rear one is simply blocked... I suspect this is blocked by the large alloy spacer as well.

This is how I've plumbed mine too: big one blocked, small ones used for Blow off and ECU/FPR.
And yes the spacer is blocking the passage for the big one.

What is the throttle body spacer for? Extra plenum volume?

The Joe Bence roller throttle tube would really help where your cable exits the shroud. It takes about half the pedal effort with it vs without when running an angle like that.
edit; on second though it looks like a pretty straight shot. Anywhere, here is the tube I was talking about;
http://www.thesamba.com/vw/classifieds/ ... ?id=786740

Ta Yvre, nice to know my plumbing a ok.

My friends just fitted something pretty similar to his beach buggy Steve, he loves it. Think, as well as a new throttle cable, that'll be my next buy.

Don't know why it's got the spacer, but coupled with the modded butterfly I've no need of any air valve thingys, and it performs really well when I'm driving slowly.

Mine doesn't...

Easy fix.... Don't go slow

yvre wrote:Mine doesn't...

Does yours have a hard time transitioning? This is why I connected the big reference line to a port above the throttle plate. Made a huge difference.