Exhaust Popping

[New2 7's]

I know most of you out there have Duratec or Zetec motors, while I'm still running a Crossflow.
But maybe this is a common question; after hard acceleration when I being to slow down the exhaust pops, is that a timing issue, to much fuel pressure or running the carbs to rich?

I've been working on the fuel mixture on my carbs and I hope to clear up the issue soon.

Scott

[magnusfeuer]

You are probably running the too lean. I suck pretty royally at carbs, but a speculative guess from my side is that you need larger idle jets. There are, however, probably much more carburator-versed people than me on this forum who can help you out.


/Magnus F.

[slomove]

I suppose popping exhaust on carbs, especially with a crossflow is just normal. There have been dozens of posts on Blatchat about that and while some people hate it, most consider it part of the character and some complain when their new fuel injected engine upgrade does not do it anymore.

When my Zetec was still running on carbs it was popping and banging like a good one. Now with throttle bodies I have the choice :)

Gert

[New2 7's]

Never new the popping sound was a regular thing with other owners. There is a road that runs near LAX and goes down to the beach area. I was on it today pushing my motor hard after adjusting the carbs to see how they would respond and as soon as I was off the throttle it would pop, not loud like a back fire.... I'm thinking about going the throttle body route something I can switch over to a duratec or zetec motor when I finally switch.... my gas mileage isnt very good, approx 15 mpg city if I drive conservatively which I dont do very often.

[SkinnyG]

My 4AGE gives one solitary pop when lifting off the throttle. Sounds just like hitting a cone. The cone chasers keep looking for the mysterious un-touched cone....

G

[johnh]

I'm still running a Crossflow.

Me too. Mine sometimes pops like this, I've been told I'm a little lean. I've played a little with the jets but haven't done any serious tuning. On PNW2007 I made if from Vacaville to Corning on one tank of gas which is about 165 miles via the route we took, so I'm getting around 20 mpg, not too bad I think, how much does that stock Caterham tank hold, anyway?

[Elv15]

John, IIRC 7 imperial gallons.