Vac pipes 'n' stuff.

[TNT ANDY]

Looking at getting my c1j finally dressed now, with just a few more bits to do. I have yet to connect all the vac pipes up, but was wondering which was the better setup? Where is it best to take the following pressures from?

1. Map sensor - Above / below throttle position - I guess below so as to see -ve pressure?
2. wastegate - Direct from compressor housing via boost controller?
3. FPR - ???

The reason I ask is because I would imagine there is a difference in pressure above and below the throttle position and would ideally like to get this spot on before mapping begins.

TNT

[Miller]

1. Map sensor - after throttle plate-
2. wastegate - i have mine connected after the the throttle plate.....i do not think it makes any difference but please correct me if i am wrong.
3. FPR - after throttle plate to reduce fuel pressure when at idle.

chris

[Big Jim]

Taking the wastegate signal from after the throttle plate means that at certain times the turbo will be working very hard, as the wastegate isn't seeing the full boost pressure being produced.
My personal preference is to take the signal from close to but before the throttle

[TNT ANDY]

1. Map sensor - after throttle plate-
2. wastegate - i have mine connected after the the throttle plate.....i do not think it makes any difference but please correct me if i am wrong.
3. FPR - after throttle plate to reduce fuel pressure when at idle.

chris

Cheers Chris - Schoolboy stuff I know, but I've never really got the hang of this part. BTW I see good things ahead for the 11. Ross is on a mission.

[TNT ANDY]

Taking the wastegate signal from after the throttle plate means that at certain times the turbo will be working very hard, as the wastegate isn't seeing the full boost pressure being produced.
My personal preference is to take the signal from close to but before the throttle

With you there Big Jim

[Miller]

Taking the wastegate signal from after the throttle plate means that at certain times the turbo will be working very hard, as the wastegate isn't seeing the full boost pressure being produced.
My personal preference is to take the signal from close to but before the throttle

Interesting Jim, what difference do you think i would see if i changed over to what you have suggested?

This is on a car that has EFI so no pressure lose through the venturi, that you would normally see on a c1j.

Cheers
Chris

[Big Jim]

To be honest probably the only difference you'd notice is a slight (and I mean slight) increase in lag. It's just that at certain larger part throttle conditions the turbo may be making boost but the pressure drop across the part closed throttle plate means the wastegate can't see it. The compressor will be creating more heat than it needs to and if you're marginal on intercooling then that heat may affect charge cooling when you need it.
If you've got a big front mount then it'll probably make naff all difference.