Jetronic fuel injection

[Mark LaBarre]

So, Anybody willing to share their jetronic tuning tips? I just upgraded to an 86 jetronic from the CIS injection. Reprograming? Timing? MSD?
Mark

[Bildon]

CIS is Jetronic.
CIS-E is EJetronic

There is no programming to be done...it's mechanical.

MSD isn't needed. The stock Bosch ignition is fine for IT. Use colder plugs.

You do however want to spend some time on the dyno getting your high RPM fuel mixture and ignition advance settings right. There is a lot to be gained there.

Short of a dyno, get an EGT guage and an inline fuel pressure guage...then tweek pressures/advance and measure gains on a straight segment of your favorite race track... 3rd through 5th pulls.

....a Hot Lap timer on an open test day is good for this.

Good luck,

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Bill Sulouff - Bildon Motorsport Volkswagen Racing Equipment

[QB]

Bill, Please elaborate. Details, we need details

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Rory

ITB Rabbit

[machschnell]

Someone pointed me towards a website with a trick where you can install a potentiometer inline with the full-throttle switch, and vary the voltage to change the duty cycle of the cold-start injector.

Theoretically, you could tune the mixture from your dash while you're driving, as opposed to using the mixture wrench in the fuel distributor - not sure if it has the same effect... So you could do this on the dyno, or at the track. I haven't tried it yet, just need an hour or so for all the wiring, etc. You can get the potentiometer at Radio Shack for a few dollars.

http://www.geocities.com/turbogti2000/tech/fte.html

I've been thinking about an EGT also, I've seen some links to aircraft sites with cheap EGTs - problem is, I don't know how to use one. Couldn't find any info on the web either, least of all for watercooled VWs. Anyone?

PJ

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83 Rabbit GTI - future ITB

[This message has been edited by machschnell (edited January 04, 2002).]

[Mark LaBarre]

My 80 scirocco didn't have any electronics, and I was concerned with the O2 sensor, frequency valve etc on the 86. Don't have my Bently yet, but I seem to remember now that when the WOT switch makes, the rest is out of the loop.
Just don't wanna be slow.
Mark

[Eric Parham]

Trouble is that using the cold start at WOT primarily enriches the #1 and #2 ports. Not a good idea unless you mount a Fox manifold with the repositioned cold start to get a better distribution (for testing only -- would not be legal for competition).

[MSPERBER]

Bill, have a question, what are the recommended egt temps for a A1 GTI running in ITB. I have two egt meters hooked up to the header. We run a max of 34 degrees advance and the standard plug. What is the your recommended colder plug and brand of plug?

Originally posted by Bildon:
CIS is Jetronic.
CIS-E is EJetronic

There is no programming to be done...it's mechanical.

MSD isn't needed. The stock Bosch ignition is fine for IT. Use colder plugs.

You do however want to spend some time on the dyno getting your high RPM fuel mixture and ignition advance settings right. There is a lot to be gained there.

Short of a dyno, get an EGT guage and an inline fuel pressure guage...then tweek pressures/advance and measure gains on a straight segment of your favorite race track... 3rd through 5th pulls.

....a Hot Lap timer on an open test day is good for this.

Good luck,

[tderonne]

Hi Mike!
Is that your old Sentra on Ebay? It popped up when I searched for "SCCA".
Or is that a twin?

Tim.

[MSPERBER]

Scary, yes thats the car, it keeps on kicking. hope they sell it soon.

Originally posted by tderonne:
Hi Mike!
Is that your old Sentra on Ebay? It popped up when I searched for "SCCA".
Or is that a twin?

Tim.