boost problems? a3 1.8t sport

[argyle89]

hey all. i got my boost gauge wired in to see if the car was boosting right! so just wondered what psi it is standard? when it boosts it only hits the 4th notch between 0 and 10 so i think its not boosting right

 

[patTTpoa]

That isn't very clear, what's the maximum PSI you have seen?

Pat

 

[argyle89]

the 5th notch inbetween 0 and 10 on the gauge is the highest its been (its in psi.) sorry it didnt make sense i wrote it quick!

 

[Prawn]

there are only 9 units between 0 and 10! something is a bit off there. cheap guage I assume?

On idle you should be around -20ish in teh vac scale, on boost, above 2500rpm you should be just over half way beween 0-10 going clockwise, so around 6-7psi of boost.

 

[argyle89]

was about 35 quid i think mate lol! it stays at 0 on idle!! have i wired it in wrong? have used the t-piece at the top of the standard dv. maybe ive split the pipe that was already on the dv befor or something???? i could hear hissing but thought that might of been normal due to the t piece?! if that makes sense?


could ya reccomend me a good boost gauge?

 

[Prawn]

it's VERY normal for them to read 0 on idle mate when you've recently got the car.

I'd say almost 100% that if it's got the standard DV fitted still, the diaphram will be split.

When you back of the throttle, do you hear a faint flutter sound?

mine read 0 when I first fitted it many years ago, and that was the first I knew about my DV being broken!

I'm yet to see a standard early car without a split DV when first bought.

Change that, and it'll drive loads better, and usually give better economy. Split DV will also cause a slight boost leak too, so you're losing power as well!

 

[argyle89]

you sir are a ledgend!! yeah i heard/hear the flutter when i back off the throttle... thought it was broke ive bought a 007p from someone on here so as soon as that arrives il get it on! do you know the pipe that goes on the standard dump valve....the funny material one?! can that be replaced by silicone vac hose? as its hissing like its leaking abit!?

 

[Prawn]

Yup, it's rubber surrounded in fabric, rip it Off a d replace with silicon ASAP.

Also, in the middle of your inlet you'll find a short pipe, 6" long and about 8mm internal (12mm external) diameter, it's part of the Pcv system, thatll almost certainly be split too and costIng you power. Almost every agu I've seen has a split in this pipe costing you boost, fuel, and power!

 

[argyle89]

Yup, it's rubber surrounded in fabric, rip it Off a d replace with silicon ASAP.

Also, in the middle of your inlet you'll find a short pipe, 6" long and about 8mm internal (12mm external) diameter, it's part of the Pcv system, thatll almost certainly be split too and costIng you power. Almost every agu I've seen has a split in this pipe costing you boost, fuel, and power!

any chance of a picture of that? dont know if ive seen it tbh. do i have to replace it or take it out? i know theres the one from the dv to under the inlet. ?(can i remove the entire pipe?) and the one next to it to the fpr? above?!

 

[argyle89]

well been and fitted the vac hoses this morning! the gauge now reads 20 on the vac and boosts to the same pressure, about 4-5 psi! now the engine hunts a bit, sometimes more than often when im sat at lights, or when i put the clutch in, the revs drop right down to 500 and 750 and it feels like its hunting!? any ideas?