Daytona Driveability Problem

Moderators: 330GT, abrent

Dogdish
Posts: 11
Joined: Thu Mar 16, 2006 9:06 pm
Location: Denver, CO

Re: Daytona Driveability Problem

Post by Dogdish » Sun Nov 23, 2014 12:54 pm

Dyke,

Can you hook up an O2 sensor, like something from Innovate Engineering? I would really like to know if your stumble is a lean or rich condition. I assume lean, but you never know.

Also any intake leaks? Can check with some starting fluid (ether) and a fire extinguisher close by. :-)

I have a US car, but set up my carbs to Euro settings. My emissions are long gone. It doesn't have a stumble.

My old Queen Mother did though. It went lean….I think they wanted another progression hole drilled or larger holes, can't quite remember. It went lean on that fraction that the butterflies opened.


Bill
365GTB/4 14097

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sun Nov 23, 2014 3:37 pm

Bill: Car is converted to full Euro specs. Have tried too lean and too rich idle jets with little difference. I agree that the "location" of the progression holes, not the number is probably the culprit. The US engine was set up to idle on retarded timing, so when the timing is advanced to Euro spec, the throttle plates have to be closed to bring the idle speed back to normal. This moves the plates further away from the progression holes and could create the "off idle" lean condition and 'bog". I realize that numerous Daytona's have had the same retro-work done and do not exhibit this condition, but it may be that this particular car has a set of carbs with the holes just slightly higher by a few hundredths of a millimeter. That is all it would take.

Dogdish
Posts: 11
Joined: Thu Mar 16, 2006 9:06 pm
Location: Denver, CO

Re: Daytona Driveability Problem

Post by Dogdish » Sun Nov 23, 2014 4:08 pm

Dyke,

The only other thing I can think of is playing with the balance bleed screws to change where your butterflies are sitting when at the proper idle speed. I am running out of ideas!!

Bill
365GTB/4 14097

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sun Nov 23, 2014 7:02 pm

Bill: Good idea, but I have already taken that into consideration.The base setting for the air-bypass screws is "closed", so as to make the throttle plates more open at idle. I appreciate your thoughts, but I believe that I have over-emphasized the problem with this post, and it is something that can be easily "driven around" in the real world.

Timo
Posts: 215
Joined: Thu Apr 13, 2006 8:56 pm
Location: Riverside, California

Re: Daytona Driveability Problem

Post by Timo » Sun Nov 23, 2014 7:40 pm

DWR46 wrote: Car is converted to full Euro specs.
OK, could you perhaps elaborate with more details ? Which, if not all, components have been replaced or (how) modified as Euro ? It's just that your above statement prompted an theoretical idea, which may or may not have any effect, but I'd like to know more details before offering any further suggestions. If you prefer not, I understand, no big deal.
Timo

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sun Nov 23, 2014 8:55 pm

Timo: sent you a PM.

User avatar
John Vardanian
Posts: 1759
Joined: Wed Sep 04, 2002 12:13 am
Location: San Francisco Area

Re: Daytona Driveability Problem

Post by John Vardanian » Sun Jan 18, 2015 3:24 am

I was talking with someone about how disappointed he was with the performance of his Jag XKE after he changed the flywheel to an aluminum one. The symptoms he described sounded much like the Daytona in this thread. I thought I'd share this.

john
PF Coupe

DWR46
Posts: 539
Joined: Tue Sep 22, 2009 8:23 pm

Re: Daytona Driveability Problem

Post by DWR46 » Sun Jan 18, 2015 11:04 am

John: I agree with your comments about aluminum flywheels. I am not a fan of them for street cars due to exactly what you are talking about. The do not store enough energy to keep the car rolling initially. OK for race cars, but not so good for the street. This Daytona has a stock steel flywheel. However, we have some new things to try once spring arrives. I will let you know how they workout.

Post Reply