Hey guys recently done quad carb conversion to twin solex's.. wondering where i can run the Vacuum advance to now. help would be awesome!

 

 

 

You'll need to find somewhere on the carbs to hook the vacuum advance to.

Sidedrafts are not reknown for their fuel economy and were designed as performance modifications. Vac advance is a pollution/economy control. They are itb's and they deliver fuel through a pulse, unlike downdraft carburettors which have a consistent vacuum. This fact makes a vacuum advance circuit unreliable due to the chatter type action placed on the stator plate.

Sidedrafts are known to have poor progression from idling to running due to the lack of vac advance.

You need to run a manifold vacuum advance system, which is different to ported vacuum, if you want to keep it and have never even looked at something like that myself.

Edited July 10, 201313 yr by GJM85

A very much better idea is to get your distributor recurved to suit your specific modifications. They will remove the vacuum advance all together.

 

In Melbourne you would go to Performance Ignition in Mitcham.

 

http://www.performanceignition.com.au/

 

Presumably there is a Brisbane specialist however Performance Ignition do stuff by mail also. Give them a call.

Good luck finding anyone in Queenshole.

Can you read the maximum advance it goes to at the moment?? You will have to make some extra marks on the pulley with 'whiteout' or 'liquid paper' or simlar, as it should go out to 35degrees or so. It should hit the maximum before 3000rpm, it will be interesting to see if you are losing any power w/o the vac.

 

The idea of it was to advance the timing at low-throttle cruise when the mixture is so weak it doesn't burn well, then drop the timing back to normal for acceleration.

 

Having the dizzy professionally sorted for over a hundred bucks would be best, but you could have a crack yourself. I learnt a lot when I re-did mine.

Ke15 race car at AJD in June. Twin webers. No vac advance.

 

Ive never worried about vacum advance,just block it like mine has been for 20years.

 

It proberly hasnt worked for years any way!!

 

rob

That's because Gary's ke15 will be driven at mostly full throttle.

 

Also there is a bloke at Ipswich that does ignition curves.

Edited July 10, 201313 yr by Trev

If you've finished doing the cam/head jobs/exhaust then the guy Trev mentoned would be good. Also go electronic ignition if you ever plan to.

 

Get the breathing mods done then last of all get the best ignition curve it will handle.

Agreed, if not using it, just stick a bung on the pipe to keep dust out.

 

But far better to tune the advance curve to the engine specs. If you spend all that money on carbs, head etc, a $100 - 150 or so on a dizzy overhaul and recurve is money well spent.

Thanks heaps for the responses guys! So I gues when I put the car in the ge jetted chocked and tuned might as well ask for a recurve as well haha!! One more question has anyone had any experience with any carby shops in Brisbane area and recommend anything?

Yeah twin side drafts = delete vac advance + recurve mech advance.