smaller pulley

[Sandy 0]

Hello Folks,

 

I was wondering I am running a 70mm pulley on my G60 which I am thinking about changing to a 68mm. I am running a mild shirck cam (bad spelling) would ma C still run OK or would I have to change my AMD chip etc.

 

Sandy G60

[GazzaG60 0]

depends on fueling

 

68 is maxxing on injectors so it maybe better to go with so reds and SNS

 

have a word with Henny as he's after some reds and you may be able to sort a deal with him as they come in 8's. expect to pay around 110 for them.

 

maybe darren or bilal or the pitstop guys can tell us what boost differences you can expect between say a 70, 68 and a 65

[h100vw 0]

It would probably run ok.

 

 

 

 

BUT!!!!! You don't want to go melting pistons which WILL happen if you have inadequate fuel for the amount of boost you are generating.

 

 

 

Best policy, like Gazza says, is get some bigger injectors and a chip to suit the pulley. Better safe than sorry.

 

Gavin

[W3RKD 0]

hello there sandy what boost are you running at the moment ? sould be expecting to see around 13-15psi on a 68 and on same charger with 65mm looking at around 16-17psi ..

we can supply red tops for £115 per set and get chips to match from bilal.

[Sandy 0]

No sure wit boost I am getting fae the 'charger (re-conditioned it myself a few months ago) but it feels fine. I've got an adjustable FPR installed on ma G60 already. Someone told me ma cam wouldn't work well with a smaller pulley is this true.

 

PS ah noticed someone (cannae mind who) wiz selling ah 68mm pulley on the forum and ah thought a few horses for little bucks but if ah need to upgrade other bits I will probably just wait as need some respraying.

 

Cheers fir the advice

 

Sandy

[Dubcharged 0]

You wont need bigger injectors unless you make at least 16psi boost. Stick a boost gauge in and go for the 68mm pulley.

 

Not sure what effect the smaller pulley will have on the chip. Assuming it was mapped for the 70mm pulley then you'll need to change the chip also.

 

Using a smaller pulley wont mean your cam will not work as well. G60 aftermarket cams are mild and give you that bit extra at around 5800-6000 rpm. The smaller pulley just means you gotta change gear earlier in the rpm range. WIth the 68mm you should change at 6300rpm so the cam will still do its job.

[Furkz 0]

blimey im pretty close to 16psi on a std setup lol

[GazzaG60 0]

a standard pulley wont make 16psi unless the crank pulley is different and even then..

 

id check your boost gauge to see if its working proper

[PhatVR6 0]

I've got a 68mm pulley and Jabba chip for sale.

[Sandy 0]

what kind of power increase would I be looking at with the smaller pulley roughly ??

 

Sandy

[PhatVR6 0]

I've heard it takes it up to 190, but I've never used it as I've never ran a G60, it came with a load of bits I bought to rebuild a G60 lump I had.

[Sandy 0]

I've already got 217bhp (din pwr)

[PhatVR6 0]

that's 190 on a standard G60 of course..

[beavis 0]

General rule of thumb. All G60's running a 65mm pulley should be running on reds, if you are not obtaining at least 16-17 psi on a 65mm /ported then you should be looking for boost leaks or the integrity of the charger itself.

 

A well ported charger in good condition can also pull in the region of 16psi on a 68mm, strong cars on 68mm can use up the max fuel provided by the greens, again red tops should be considered.

 

Another factor is cams, although only 14-15psi may be displayed on the boost gauge it has to be considered that this is just manifold pressure displayed and not what is in the combustion chambers, so you are not getting a true picture of what is going on. A simple way of looking at it is there is going to be more air in the cylinders on a cammed engine with a which will need more fuel to keep the A/F ratio in equlibrium. Again Red tops should be considered as greens will be streched or not providing enough fuel.

 

Invest in a A/F gauge or get a wide band lamba test done on your car if you are in doubt.

 

One factor people overlook is that the orginal injectors are getting long in the tooth now (although they are pretty reliable) and are starting to give up the ghost. We have seen several G60/G40's the latter part of last year go on meltdown on one piston though a injector dying and running the particular cylinder lean. The cars were all of variying specs aswell, completly standard to tuned to the nuts. Those sticking with greens should consider getting their originals rebuilt and flow tested for peace of mind.

 

Red tops expand the safety margins, they are well within safe working parameters in a g60 lumps, where as the greens are running at their limits.

[h100vw 0]

Red tops expand the safety margins, they are well within safe working parameters in a g60 lumps, where as the greens are running at their limits.

 

Red tops at 115 quid are a bargain really. Ok you need a chip to go with it but that still only another hundred or so. IMHO its not worth having your std injectors fettled with those prices. Assuming of course you can do the work yourself.

 

Most folk have got pulleys and ported chargers already. Why not go that extra mile :?: Check with Henny the cost of a basic rebuild on a blown engine! :oops:

 

Gavin

[PhatVR6 0]

Why fit bigger injectors? why not just fit a 4.0 bar FPR?

[beavis 0]

Why fit bigger injectors? why not just fit a 4.0 bar FPR?

 

There is only so far you can go upping the pressure, the injector atomises the fuel as it fires. When upping the pressure too much you risk just turning the injector into a hose pipe and just jetting fuel in un atomised. This leads to a poor burn in the cylinder

[Dubcharged 0]

Also the standard fuel pump runs at its maximum on the 3.5bar fpr. The 4 bar would push the 8v pump too far. To run a 4bar fpr reliably you'll need to uprate the pump to a 16v one.

[nikosg60 0]

i am trying to find a reason why he have to change the green injectors?

my car is running on a 65mm pulley without probs at all.i have only put a 3.5fpr and thats all.i would recomend to put a halmeter together with a boost gauge before you do anything.

cheers.

 

 

****MOD EDIT***** post de-capped-vr6storm

[W3RKD 0]

i am trying to find a reason why he have to change the green injectors?

my car is running on a 65mm pulley without probs at all.i have only put a 3.5fpr and thats all.i would recomend to put a halmeter together with a boost gauge before you do anything.

cheers.

 

 

****MOD EDIT***** post de-capped-vr6storm

 

have you put a wideband on your car ?? i think this will expalin all to you.. :lol:

[beavis 0]

Think of it like a absailing rope, prefer to dangle off a cliff with a rope that is only caperble of supporting 14kg if you weight 12kg or a rope that is caperble of supporting 30kg. Both ropes do the same job, just bigger safty margin in the latter, so if somthing goes tits up then you have a bigger net.

[andycowuk 0]

Sandy, regarding the extra kick u are looking for........

 

I noticed on a copy of your rr print from the 1/12/03, that you have not done anything with your ISV. You hit 0.8 bar by 3k, and it goes no higher. Unless u sort this, there is no point putting on a smaller pulley.

 

Sorting this out alone, will give u a bit more power.

 

HTH

[Sandy 0]

What do I need to do to sort the isv out ??

 

Sandy

[andycowuk 0]

a one way or check valve to stop the isv leaking the excess boost, but still allow it to perform its idle functions.

 

I havnt looked into suppliers myself as i dont break 0.8 bar (yet). this may also have implications on your fueling. Check with darren or steve.

[Sandy 0]

Fuelling shouldn't be a problem as I've got an adjustable FPR installed. Does anybody sell a kit/parts for this and how much would it cost ???

 

Cheers

 

Sandy