80 rabbit 1.6L (EGT ?'s)

hey guys,
Got the new car out to the track this weekend. First off let me say our friend that supposedly knows alot about VW's set the timing by ear. This was because I read that some rabbits had flywheels with incorrect stock timing marks. OK so we set it by ear. Anyway we get to the trrack and at WOT the rpms stop climbing and the car sounds like its missing. barely revs higher. when only having the one butterfly open the car will rev freely to anywhere you want. (negating timing issue right?) We verified the fuel pressure of system and did all of thevarious pressures your supposed to get. they all checked out fine.

To somewhat correct the problem we adjusted the screw connected to lever on diaphram. We riched it up to the point where it was smoking from being so rich. This somewhat remedied the problem and seemed to rev better.

The EGT's on this last run were in the 1600 degree range. Is this close to the danger zone? Also what kinds of #'s are you guys running.

Why did we have to richen the crap out of it so that it would rev??

Any help is appreciated.
Ron Davis

Ron,

1600 is way high on the EGT, and would indicate that you're running very lean. Do you have a wide-band O2 sensor w/ an A/F gauge? If not, I would suggest that you install one. Especially if you're trying to time this thing 'by ear'. I also suspect that you've got the timing too far advanced.

As Bill mentioned, you need to do better with your timing. Why not verify the flywheel by setting Top Dead Center on your number 1 cylinder and see what marks on the flywheel you have? It seems all the gremlins I have had to deal with happen under load (WOT at the track), never revving it in the paddock or driveway. A motor can have all kinds of issues but sound fine when "free wheeling".

See if you can elimate timing as an issue, verify that the ignition system is okay and look for causes of fuel starvation at high demand (so easy to say and so tough to figure out!!)

good luck

Too lean is the most likely but it could also be due to timing too retarded. Fuel doesn't all burn in head so it keeps burning in the exhaust.

However, it does sound like you are too lean since richening it seemed to help. My first recomemdation is to time it using the flywheel since it should be more accurate than most people's ear method.

Make sure your frequency valve is buzzing if you have the newer FI. I don't think the 1.6's came with the O2 loop though. You can probably enrich the mixture by insulating your warm up regulator. Take it off the motor and insulate it from the engine bay heat which will keep the mixture richer until the regulator heats up.

1375 is where I shoot for EGT's on my 1.8 LP GP motor.

Even with an adjustable timing light, you can set your timing to a "static" mark @ 5,000 RPM and don't worry about the timing marks.

I set my LP GP Wabbit to around 28-32 degrees @ 5,000 rpm. At least that's what I remember. It's been a couple of years, but I recall that's where it should be.

First off, get the car timed properly. getting an engine running by timing it by ear is one thing, for performance you need a timing light.
What revs is it bogging down at?
Open exhaust or stock?
EGR plug still in the Throttle body?
Are the points new?
Fuel filter?
Air filter?
What's been done to the engine?
Cam properly timed?

My 1.6 would rev freely to 8000 all day long, my egt was 1450 to 1500.

I would get the manual and go through everything engine related. It doesn't sound like your friend knows as much about VW's (or cars) as he's telling you.

Quote:

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Originally posted by Mark LaBarre@Nov 2 2005, 06:53 AM
First off, get the car timed properly. getting an engine running by timing it by ear is one thing, for performance you need a timing light.
What revs is it bogging down at? ANYTIME AT WOT
Open exhaust or stock? 4 INTO 2 INTO 1 THEN STRAIGHT PIPE
EGR plug still in the Throttle body? YES
Are the points new? PUT IN COMPUFIRE ELEC IGGY
Fuel filter? NOT SURE GOTTA SPARE, FP DOESN'T DROP
Air filter? ALSO NOT SURE, CHEAP ENOUGH TO REPLACE
What's been done to the engine? NO IDEA WON THE CAR IN A RAFFLE
Cam properly timed? GONNA CHECK TOMMOROW =)

My 1.6 would rev freely to 8000 all day long, my egt was 1450 to 1500.

I would get the manual and go through everything engine related. It doesn't sound like your friend knows as much about VW's (or cars) as he's telling you.

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I answered you questions in your quote. FP stayed constant the entire time. I really think it's timing is retarded. to compensate for retarded timing it we would need to lean it out so it idle (becuase of late spark) As the revs increaseit leans out. We then richen it out like a mother, smokes at idle but because spark is so late, alot of energy is exhausted, resulting in EGT's .

Why oh why can't induction be simple like a first gen rx7 =)
I'll let you guys know how it comes out tommorow.
I really appreciate all of your responses!

Thanks,
Ron Davis

Thanks for all the help everyone. We were set at about 1 degree BTDC. The "rich" mixture isn't all that rich when your running 9 BTDC. We found records and the old owner ran that. EGT's are low now so lookin good.

Ron Davis