ive got a sc 14 running a su and it is idling really funny ive talked to a few people and they say there is to much air gettin forced in at idle it runs fine one i take off.. i need to no how to fix it asap any help would be good thanks johnny t

its blowing to much air on idle how can i fix that???

NickZ is the man you wanna talk to, his bro has a charged 4k! thats injected however.

 

Couple of things I can think of though are: is the butterfly closing all the way propperly??

also do SU's have air bleeds like webers etc?? could these possibly be a bit too big!?

have a look at what the piston of the SU is doing at idle. you should be able to feel it/see it with the air cleaner off. does it flutter up and down, or does it lift up a fair way?

 

it could be lack of oil (or too light) in the dashpot. the dashpot spring being to light. the mixture may be set wrong.

 

what type of SU is it?

Edited July 14, 200620 yr by Felix

This is Rolla_Boy's old setup.

This is Rolla_Boy's old setup.

 

so is this on a 4k!? cause rolla_boys was a 5k! correct??

Felix, it's the Saab Stromberg....and I had it on my 5K, and I also had it on my standard 4K in my KE30 and it ran fine. From what he has told me, it's just idling up and down like all SC cars do....It probably could use some more oil in the dashpot though. Mine used to idle up and down like that too, if I had to sit at lights for AGES, and it was pissing me off, I used to just turn the SC off, and it would idle normal. Or just accelerate a little.

ok, didn't realise it was your old strommie Rolla__Boy. the CD strombergs don't have a dashpot, they use a diaphram, but work on a similar principle.

 

i'd try maybe having a play with the idle mixture, to see if that helps things. could possibly be a bit rich and starts to foul the plugs a bit when it sits for a while. also as Rolla__Boy stated, a lot of drawthru supercharged engines do lope a bit on idle, maybe it has something to do with pulses from the blower.

 

you could always get it dyno tuned....

and if that don't work, ill be happy to buy it haha,

i can put of with a dodgey idle, lol

hey um had my car looked at it and the diaphram had a hole in it and it kept flooding its self.. its gettin fixed atm but he has to find a diaphram because they dnt make them new nemore!:hammer: so my car could be off the road for a while.. yeah I'm gonna get it dino tuned and hopefully it will be fixed!!

i'd maybe look into converting it to an SU. much easier to find bits and pieces for. pretty sure they have the same mounting flange as the CD strombergs.

Mine had a dashpot dude

I had that carby apart not long before you bought it and the diaphram was perfect. You can buy those carbies complete for $66 delivered, and they are so easy.

hey yeah i got it fixed new diaphram ,needle and seat and dino tuned and it still idles like it did but not as hard..i just turned the idle up so it runs with the supercharger on they said the only way i can fix it is to fuel inject it!but i dnt have the $$$ to do that also it probably isnt worth doin it...dunno see what hapens johnny t