Idling with ITBs

redjetta · Post by **redjetta** » Mon Feb 20, 2006 11:29 am

I'm rebuilding a motor (4-banger VW) and doing a couple of cheap internal mods, and one or two expensive ones. MegaSquirt is certainly going in. I am considering ITBs, but just figuring some stuff out first.

I haven't seen or bought any ITBs just yet; I am considering the Suzuki GSX-R setup as it seems to be popular and reliable, and cheap. My question is about the idle. How is it adjusted? I have thought about the stepper motor setup with MS-II, but it seems expensive, and difficult to do with ITBs. A solenoid bypass also seems difficult. If you have Suzuki ITBs, how is your idle air adjusted?

nobbi1977 · Post by **nobbi1977** » Tue Feb 21, 2006 4:18 am

Sorry i thought i posted here yesterday.

Most bikes just control how far open the butterflies are for idle. There is an adjuster that comes out under the frame that adjusts much like an old carb.

You can it on the left of the photo in this Ebay add.

these Kawasaki TBIs look to have take offs for MAP aswell

redjetta · Post by **redjetta** » Wed Feb 22, 2006 2:47 am

so, to pull/push this lever, i would also have to source a solenoid from these bikes? your answer certainly helps - now i know how the idle is controlled on the bike - but how do you guys with ITBs and MS control your idle?

nobbi1977 · Post by **nobbi1977** » Wed Feb 22, 2006 12:54 pm

Its more a case of fix the idle and leave. I am going to use the ignition timing to hold my idle on my cbr600 bodies

Are you talking about controlling the fast idle (warm up)?

redjetta · Post by **redjetta** » Wed Feb 22, 2006 1:12 pm

nobbi1977 wrote:Its more a case of fix the idle and leave. I am going to use the ignition timing to hold my idle on my cbr600 bodies

do you mean playing with the low end of the ignition table until it idles smoothly? i'm still new to megasquirt. volkswagen digifant 2 management has a stabilizer valve that is constantly adjusting the idle speed, which is why these cars are constantly "hunting".

http://cwpc.ca/mk2bentley/FU01/ch7.3.2.html

Are you talking about controlling the fast idle (warm up)?

yes, my question was really trying to cover both idle adjustment and warm up air. would i even have to deal with a fast idle valve, or are warm-up fuel enrichments in megatune plenty enough?

GeorgeGt · Post by **GeorgeGt** » Sat Mar 04, 2006 4:12 pm

if i would go for ITB`s setup , i would not use fast idle/idle control at all. On my last setup , i didnt use any idle controlling and it was fine(in winter and in summer). That was on 2.0L 4banger opel with PAS , never had any problems. And idle was perfect , only dropped by 100 rpm when u turned the weels at idle

redjetta · Post by **redjetta** » Sat Mar 04, 2006 7:28 pm

interesting. thanks for the input.

bcal · Post by **bcal** » Sat Mar 04, 2006 11:53 pm

For warm up I just used a simple anti diesel soleniod off an old carby.

Works a treat

For hot idle I just used the suzuki adjustment which has a short cable with a knob on the end. This was real handy because a screw adjustment would have been difficult to access.

The suzie TBs also have screw adjustable air bleeds on the underside. If these are closed the engine may stumble coming off idle. Mine worked best at 1 1/2 turn open.