expected boost with 65mm pulley

[dannyb.G40]

This has been an ongoing problem for me, so i am looking for a definitve answer.

With a 65mm pulley, still running twin v-belts how much boost should i be seeing?

I know different components such as gt inlets are going to affect this, but analogue boost gauges don't tend to be that accurate and im not asking to decimal figures lol.

I only get 10psi and maybe 12psi in fourth and fifth, tried two different gauges and still get the same figure. I don't think this is enough, i can't find any boost leaks or anything and before i take it to a garage i want to check im not looking for boost that isn't there!

Thanks for the help, Danny

[hayesey]

the belts are probably slipping and stopping you getting more.  With toothed belts I'd expect to see about 15psi.  Is the charger standard or ported?

[dannyb.G40]

stage 4 ported about 5000 miles ago by jabba

because i get higher boost levels in fourth and fifth when the crank speed isn't accelerating as quickly, like you said that probably points to it being the belts slipping doesn't it haysey?

I remember reading ages ago about something you could spray on the belts to make them more grippy, any ideas what it might be? The belts are as tight as i can get them at the minute

[hayesey]

yes I'd say that sounds like belt slipping.  You can get belt dressing stuff yes, I can't remember what it's really called.

[G40supercharged]

Do you have an induction kit? The original unmodified airbox will massively limit the maximum boost with 65mm pulley/R1. I got about 15psi maximum with 65mm V belts, R1, big cone filter, standard manifold/throttle body.  Mine would show 10psi by 3000rpm.

[scotsjohn]

yes I'd say that sounds like belt slipping.  You can get belt dressing stuff yes, I can't remember what it's really called.

Any Bearing/Belt supplier will stock dressing at about £7 a can, but it's pretty messy stuff which doesn't last very long. Think about a toothed belt,really works well and much less wear on charger bearings.

[dannyb.G40]

Cheers for the replies

G40supercharged: I have a cone filter but it is tiny, nowhere near as big as the Jabba one for example. I might see if i my mates have got a different filter i could try.

Scotsjohn: I think your right, i aren't gunna bother with the belt dressing. Toothies are the next thing on my list!

Has anyone had any experiece of the kit that is constantly on ebay?

[Ä‘uro]

Cheers for the replies

G40supercharged: I have a cone filter but it is tiny, nowhere near as big as the Jabba one for example. I might see if i my mates have got a different filter i could try.

Scotsjohn: I think your right, i aren't gunna bother with the belt dressing. Toothies are the next thing on my list!

Has anyone had any experiece of the kit that is constantly on ebay?

I bought it nd hd slight problem with belt - it was to big (1000 mm) nd cos of that hd to put tensioner. For 65 pulley belt should be 985 mm but it's not in production. After putting tensioner everything is ok!

[PeteG40]

our supplier can get 960mm belts


6n g40 has one on here and said with a 1000belt it was too tight really (hard to get on) and that was with a 60mm pulley

[josé]

I just bought one off ebay its a quality bit of kit considering its steel pulleys they've got a right nice whine when you put your boot down i definately noticed a difference going from v-belts to toothed belts,

only thing i had to do was change the timing marks on the bottom pulley

[NealPeal]

I got some belt spray from local bearing shop, and it stopped the audible slip at high revs on v-belts.
Well worth a go for the £5 it cost.. It was called "Belt Dressing Spray" and makes everything pretty tacky..
NEAL

[Glader Poison]

Cheers for the replies

G40supercharged: I have a cone filter but it is tiny, nowhere near as big as the Jabba one for example. I might see if i my mates have got a different filter i could try.

Scotsjohn: I think your right, i aren't gunna bother with the belt dressing. Toothies are the next thing on my list!

Has anyone had any experiece of the kit that is constantly on ebay?

I bought it nd hd slight problem with belt - it was to big (1000 mm) nd cos of that hd to put tensioner. For 65 pulley belt should be 985 mm but it's not in production. After putting tensioner everything is ok!

Do you have the direct link to the sale on ebay?

G-reets,
Bruno

[dannyb.G40]

Update with this problem, I recently fitted toothies partly to see if it resolves my boost issues but also cos its the next sensible mod.

Unfortuntely it didn't really make any difference with me still seeing about 10psi (.7 bar) through the majority of the rev range, peaking at about 12 (0. in the later gears.

I have tried a different boost gauge,
tested (crudely) for boost leaks and as far as i am aware there aren't any,
checked the BRV and it is closing fully
and had the charger rebuilt and ported to stage 4 5000 miles ago.

Since having the car i have changed the timing belt. If this was out, say a tooth, could this affect boost? The car revs freely but doesn't idle very well and nearly stalls when the throttle is lightly pressed. Both symptoms I had prior to changing the belt.

If it is not this i am running out of ideas, should i be worrying there be something wrong with the charger? Brian said it was fine when i went to collect it and there has been no change between before and after the rebuild.

Any and all suggestions are welcome, maybe im looking for something that isn't there.

Thanks for reading

Danny

[Alexiskayak_7]

You had the same or even more boost before rebuilding the charger?