Thanks Greg,
That's only one of the things I'm working on today. Building a new dash and
rewiring, what a mess!
Cheers,
Rich
-------------- Original message ----------------------
From: gtwincams <gtwincams@pacbell.net>
> Hi Rich,
>
> That's a complicated question - are you going for really accurate
> tuning, or just close enough? If the former, you either need to have the
> car tuned on a chassis dyno ("rolling road" in Brit-speak), or get one
> of the AFR meters that are available. The cost can be high for the
> logging types, but they are worth it because you can download real-time
> data to a computer to show A-F mixtures at different RPMs, etc.
>
> In general, using tube headers requires adjusting your carb(s) for a
> richer mixture; headers are designed to be better at scavenging exhaust
> gas, which tends to increase vacuum, which can lean out the mixture
> through the carbs. More specifically however, unless you know that your
> carb was tuned correctly for your stock exhaust, the lack of baseline
> data will make further adjustments hit-and-miss, which is the "close
> enough" approach. Plug cuts can help but aren't really that accurate,
> particularly because cuts should be done at high revs, preferably under
> load, which is when these engines sometimes tend to run-over, defeating
> the test.
>
> I'm not an expert on DGVs - I've only tuned a couple - but there is some
> good info online. Try Googling "tuning Weber DGV", and you'll come up
> with several. The good news is that these are easier and cheaper to dial
> in than sidedraft carbs, wither Weber or Dellorto.
>
> Here's one site just for Spitfires and GT6s -
> http://www.triumphspitfire.com/weber.html
>
> I think you'll find that you can do a serviceable job of getting your
> carb close (fair gas economy, limited stumbling or flat spots, etc.),
> but it will take some reading and fiddling (suggest lots or reading
> first). Obviously, either an amateur or pro who has tuned for this carb
> on this engine with headers will have a better idea of where to start...
>
> Cheers,
> Greg
> _______________________________________________
> Nobbc mailing list
> Nobbc@autox.team.net
> http://autox.team.net/mailman/listinfo/nobbc
_______________________________________________
Nobbc mailing list
Nobbc@autox.team.net
http://autox.team.net/mailman/listinfo/nobbc
|