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tuning the XU5

Posted: 12 Dec 2011
by scooters
Just completed 420 high speed miles in the Meteor speed hitting over a ton on the empty bits through a nasty storm...car was.faultless.

I'm thinking about squeezing a few more horses out of the 16...

I don't want to compromise the reliability so think the best route would be twin carbs....the sole I have is a single with double barrel.

I know that twins on a 16 was an early option...any ideas what to fit? Probably be cheaper to buy that gti on eBay just now!

Re: tuning the XU5

Posted: 13 Dec 2011
by docchevron132
Weber 45's would give it some epic grunt if tuned for the rev range properly. Which can be a faff. I did it to a mates ages ago, years ago in fact, it went like shit off a shovel and returned high 20's round town.

Re: tuning the XU5

Posted: 13 Dec 2011
by Vanny
replace with 1.4d and turbo charge. Mr Allard has a book on the exact subject!

Re: tuning the XU5

Posted: 13 Dec 2011
by Philhod
It rather depends on how you want the horses to respond. Twins give great acceleration but can be a pain to keep balanced. A larger jetted twin choke weber will give a good push and increase top end... a lot, without the need for trueing up once a month.

Re: tuning the XU5

Posted: 13 Dec 2011
by mnde
Hi Rich - PM sent.

Mark.

Re: tuning the XU5

Posted: 13 Dec 2011
by mnde
On the subject of tuning, what I *really* wanted to do was to get the BX on a rolling road to find out how many horses it had, and find out exactly why it was still pinking under certain conditions (on 95 with octane boost), why the flat spot on lifting off during harsh acceleration - e.g. onto a motorway, and why the flat spot/bogging down at low revs - e.g. trying to squeeze into a gap on a roundabout in 2nd and climbing steep hills - steep enough to require the 2nd choke in 2nd gear I guess... and what I could do to liberate any lost horses.

I never got a chance to test the vacuum adv was working properly for instance, or fine tune the mixture.. and with the spare Solex to rebuild, you'll be able to fine tune all the settings to perfection. I certainly knew if I'd got the timing in the sweet spot - but I think there are other forces at play. My previous Meteor's engine felt immense (to me it didn't feel far off the output of the 2.0 Mk1 Mondeo my dad had at the time) - and that was standard.

Mark.

Re: tuning the XU5

Posted: 13 Dec 2011
by Philhod
Swap your spare Solex for a spare Weber and build to spec and you will feel a difference