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View Full Version : Hmm... dissapointment



A20A1
08-13-2002, 05:35 PM
Well in search of extra off the line boost I decided to dig deeper into the advancing system.

I've used vacuum restrictors before but I never knew how much vacuum they held and how fast they could cycle from 0 - 20 inches of vacuum.

I figured if the cycling rate was slower the the throttle rate you would still have vacuum advance engaged under hard acceleration. Which turned out to be true, but the maximum flow semed to limit the vacuum signal to about 8 - 10 inches.

even when I snapped the throttle closed the vacuum signal wouldn't rise. So acceleratiohn ended up worse in some cases.

but the idea is sound...

If I used a one-way check valve to supply vacuum to help quicken the cycle time, then a restrictor running parallel to the check valve could be used as a vacuum bleed, so that vacuum advance wouldn't always be on under wot, but would still delay the drop of vacuum to 0".

POS carb
08-14-2002, 03:25 PM
if you run a check valve along with the restrictors on another line you can have it so vacuum is applied quick through the check valve and has to escape through the restrictor.

A20A1
08-16-2002, 09:35 PM
yeah that was the idea... but I'm all out of check valves.... hey I'm getting the jets and adapter plate for the carb soon.

POS carb
08-16-2002, 09:37 PM
i can get u some, what's your addy

A20A1
08-16-2002, 09:45 PM
oh dude you're alive... hehe I haven't seen you post nonsence in the off-topic section in a while...
Still want the weber stuff? paul aerodeck has been asking for the part # for the plate.... the damn thing cost $50. I think hes using the 38mm synchronous. They should mount on the same plate though yeah?.

Anyways I can just drop by the store and pic a check valve up for $3.00. or I can dunp out my storage bin and see if one fell to the bottom.

Oh I had a dream I mated a accelerator pump from a holley or eddlebrock to the keihin... and I mande lots of $$$$ :D :D

POS carb
08-17-2002, 11:32 PM
lol

well I hope they are the same cuz I was going to get a 38/38 but I guess I could start with a 34/36 progressive

88LXi68
08-18-2002, 01:13 PM
A20A1 I think its time to convert to 5spd to help off the line.

A20A1
08-18-2002, 01:40 PM
Oooooookay... had some fun running in and out of checkers getting vacuum "T" fittings.

Well anyways I hooked it up and it's sligtly better... Slammin the gas vacuum drops to about 2" and then slowly goes to 0"

The delay is almost enough to cover the low vacuum from my high duration cam at low rpms.