Sienna PI Posted August 25, 2011 Posted August 25, 2011 Can anyone point me to a thread about possible problems with Petrol Injected Triumphs running at altitude thru' Alpine passes etc.Many thanks!
JohnD Posted August 25, 2011 Posted August 25, 2011 Can't remember what threads, but you might search the 10CR posts.The problem is that Pi modulates the amount of fuel injected according to the pressure in the inlet manifold. As the throttle opens, the pressure falls and more fuel is injected. At altitude, the low atmospheric pressure causes the whole range of throttle opening to be shifted towards more fuel, so that the mixture becomes richer and richer as you ascend. On the 10CR, Bin and I in his SuperSix could only just get over the Col 'd'Iseran, at 2770meters the highest road pass in the Alps.Adjusting the standard metering uinti is posisble, in theory, bit far from easy even in your home garage - to do so at the road side, and progressively as you ascend would be very time consuuming.Lucas produced for Triumph some special 'Alpine' M/units, but they are rarer than a hair on Kojak's head today, but you can pick one out easily - see pic.JOhn
thescrapman Posted August 25, 2011 Posted August 25, 2011 If your car is totally bog standard PI, you will probably be OK climbing the hills, might get a bit breathless, but you should make it, just keep the revs up!Everyone that has had major issues in previosu years has had a car that is non-standard in some way.CheersColin
jonnyk5614 Posted August 25, 2011 Posted August 25, 2011 Non PI I know but my Spitfire was so rich and down on power on the Iseran that she couldn't hill start on more than 1/3 steering lock! You'll all make it over but the cars won't be happy.
Sienna PI Posted August 28, 2011 Author Posted August 28, 2011 Thanks to all your replies-Hopefully see some of you at the top then!!!!!!!!!!
andy thompson Posted August 29, 2011 Posted August 29, 2011 I think if you have a well set up PI - ie capable of high 20's to low 30's mpg on a run then you will have no real issues just the usual lack of go and slightly rich at the top of passes. My PI went over Gross Glockner on a Munich beer fest trip and was better than a 1.8 Mk1 Golf GTI we were chasing once above 2000m ;).That car was good for 32mpg cruising at 75-80mph so set up just right. If you have a 22mpg slurper you will be fouling plugs at the top of the big passes.
Sienna PI Posted August 29, 2011 Author Posted August 29, 2011 Not really sure what the mpg is now - sure goes better since Moordales tuned it a couple of years back! I have plenty of spare spark plugs that i will now take with me!!!
david langrick Posted August 29, 2011 Posted August 29, 2011 i agree with andy T. MPG is the key, it gives you an idea of how rich/lean you are at at sea level. On the 2007 event up the Stelvio my PI 2.0 litre was unaffected by the altitude as it is set fairly lean . The other PIs of Shackford and Andy's brother Doug richened up quite a lot but still ran OK. I think JS had to clean his plugs afterwards.
andy thompson Posted August 29, 2011 Posted August 29, 2011 Not long now - European decoke session awaits - currently drinking Heineken at Toronto Airport - quick trip to Manitoba then 10CR LOL
TRTOM2498 Posted August 29, 2011 Posted August 29, 2011 My TR6 was fine in 2005, but this is a different TR6, with different cam. We shall see. I removed a plug a Mallory, and looked a little lean. Now richened half a turn, will check pug colour tomorrow, see what we have. Hope to not have to mess about with plugs to be honest !
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