Burbles and pops

[jamesdennison]

6 Cylinder 2000 engine with twin strombergs

 

I have lots of burbles and pops when lifting off the throttle at any speed.  Sounds cool for a bit, but does this hint at an incorrect set-up?

 

Full sports exhaust (bell) 

Tappets at 010

Timing at 10 BDTC

Electronic ignition

Colourtune is dark blue which in theory means the mixture is spot on

Carbs balanced using air meter

Checked for pinholes in diaphragm - looks ok

 

My guess is that this is just a consequence of the full sports exhaust?

 

James

 

 

 

 

[Clive]

Quite normal 

 

My understanding is that the butterflies shut, stopping virtually all air entering the engine. Lots of vacuum pulls excess fuel into the engine, and some of that ignites in the exhaust, or sometimes as it leaves the exhaust. My old car on dellortos was great at that, go down a country lane at night with the overhanging trees, and lift off. Nice flame out the back easily visible lighting up the tree canopy, accompanied by the obligatory pops/bangs.

Not that I condone this behaviour of course (well, not in a built up area)

The later SU carbs had an over-run valve in the butterfly to help stop all this. Spoilsports.

[jamesdennison]

I assure you that my car is anything but normal 

 

Thanks for the reassurance.  Not noticed flames, but sounds like an excuse for an evening run with a friend following.

[Clive]