mike barrett Posted March 24, 2015 Report Share Posted March 24, 2015 Would be interested in other peoples fuel consumption. Yesterday I did a trip from Cambridge to Doncaster (to see the Vulcan - great) and back. All on the A1 at 70~75 mph and got 23mpg, there and back with the top down. I was hoping for a bit higher mpg. My TR6 is a 150 bhp 1973 with OD. It seems to be running well with lots of grunt but does seem to be running a bit rich (going by the plugs and exhaust). cheers mike Quote Link to post Share on other sites
RobinTR6 Posted March 24, 2015 Report Share Posted March 24, 2015 25\26 is about mine, may get it bit more with a bit less right foot. Managed near on 30 in my previous TR5 but that was down to Southern France probably averaging high 50s mph. Had a SU carb Tr6 that easily did 30+....not quite as muck poke tho. Quote Link to post Share on other sites
Guest ntc Posted March 24, 2015 Report Share Posted March 24, 2015 Your missing 4/ 5 mpg so you are running rich. Quote Link to post Share on other sites
Graze Posted March 25, 2015 Report Share Posted March 25, 2015 Mike My 6 is running rich also (awaiting new throttle bodies) and I got about 26 mpg on a round trip Brisbane, Sydney, Brisbane - about 1250miles graze Quote Link to post Share on other sites
mike barrett Posted March 25, 2015 Author Report Share Posted March 25, 2015 thanks for all the comments. Seems that it should do more than 23! Will have to think about the metering unit (thanks Neil). cheers mike Quote Link to post Share on other sites
Marc R Posted March 25, 2015 Report Share Posted March 25, 2015 Just a stupid question from a continental “Frog” (l./100 Km) , when you are talking about mpg between guys from UK, Australia & NZ and US (not yet the case in this post but it may happen) is everybody consider Imp. mpg (vs US mpg) ? As fare I know in Australia & NZ they use liters, in UK Imp. Gallons (4,55 l) and in US US Gallons (3,8 l). BTW please find a useful link for car enthusiasts w/ direct conversion concerning consumption (Imp. mpg, US mpg, l/100 km), vulumes (Imp. Gallon, US Gallon, Liter), speed (mph vs kmh)…. : http://www.tdiclub.com/misc/conversions.html For the distance it is ok no issue w/ land miles (1.609 m.) vs nautical miles (1.852m)… unless we are in contact with a Triumph enthusiast owning an amphibian car w/ a Triumph Herald engine. Regards Quote Link to post Share on other sites
mike barrett Posted March 25, 2015 Author Report Share Posted March 25, 2015 Marc. sorry old school. In my case miles and UK gallons. I understand the problem, I work in the Oil industry which still works mostly in imperial units. Very strange to get drawing in inches! but you get used to it. I had a report recently of a bit thread that used units of 1/64 inches...... Mike Quote Link to post Share on other sites
Graze Posted March 25, 2015 Report Share Posted March 25, 2015 Marc Yes kms and litres here now ( although mpg and miles when I started driving). My '75 TR6 has km and miles per hour on the speedo. Graze Quote Link to post Share on other sites
AlstrMK Posted March 25, 2015 Report Share Posted March 25, 2015 (edited) reminds me of when I got my first job working for the UK Foreign Office. I was spending some time in a metal shop and someone brought in a drawing of something they wanted me to make out of box steel. I made it as per the drawing and then phoned the guy to tell him it was ready and that me an a couple of guys could help him put it on a truck for him. He replied "no, need I'll just stick it in my boot".....I was confused.... until someone pointed out that 140 meant 140 millimeters...not 140 centimeters...my introduction into more precision work!! It's important to make sure you are both working in the same mesurements Edited March 25, 2015 by AlstrMK Quote Link to post Share on other sites
simonjrwinter Posted March 26, 2015 Report Share Posted March 26, 2015 On a long steady (70-ish mph) from Essex to Exeter and back, my TR6 averaged 29mpg That's a mildly tuned 3.5 V8 with a Stag gearbox (28% O/D) Simon Quote Link to post Share on other sites
Peter Cobbold Posted March 26, 2015 Report Share Posted March 26, 2015 On a long steady (70-ish mph) from Essex to Exeter and back, my TR6 averaged 29mpg That's a mildly tuned 3.5 V8 with a Stag gearbox (28% O/D) Simon .... and with properly lean cruise mixture and spark advance appropriate for lean, part-throttlle running. Neither of which can be enjoyed by the PI 6s. Peter Quote Link to post Share on other sites
Lockley210 Posted March 28, 2015 Report Share Posted March 28, 2015 I Fitted an Innovate MTX-L Air / Fuel ratio gauge and wideband o2 sensor. Adjusting the meetering unit myself has now improved my mpg to 28 on a decent run. Added bonus is that my clothes dont smell of exhaust fumes anymore. Mark Quote Link to post Share on other sites
JohnG Posted March 28, 2015 Report Share Posted March 28, 2015 Is there an idiots guide to adjusting the MU? I need a leaner mixture and would like to take a crack at it myself, if it is considered within the capabilities of the common man Quote Link to post Share on other sites
Marc R Posted March 28, 2015 Report Share Posted March 28, 2015 reminds me of when I got my first job working for the UK Foreign Office. I was spending some time in a metal shop and someone brought in a drawing of something they wanted me to make out of box steel. I made it as per the drawing and then phoned the guy to tell him it was ready and that me an a couple of guys could help him put it on a truck for him. He replied "no, need I'll just stick it in my boot".....I was confused.... until someone pointed out that 140 meant 140 millimeters...not 140 centimeters...my introduction into more precision work!! It's important to make sure you are both working in the same mesurements Same issue on my side, student summer job in the Us in a warehouse w/ a big mistake to build up partitions. Regards Quote Link to post Share on other sites
Marc R Posted March 28, 2015 Report Share Posted March 28, 2015 Is there an idiots guide to adjusting the MU? I need a leaner mixture and would like to take a crack at it myself, if it is considered within the capabilities of the common man +1 w/ John/ wjgco maybe not a lean mixture but a leaner one ! Any guidance ! I see a lot of information, charts... available on the web but no real advise on how to do it/ at least basic stuff. Regards Quote Link to post Share on other sites
Peter Cobbold Posted March 29, 2015 Report Share Posted March 29, 2015 (edited) We're at risk of forgetting that mixture and spark timing go hand in hand. There's not a lot of point in leaning the mixture without also advancing the spark. A typical engine at cruise rpm will need around 45-50BTDC to compensate for a leaner mixture that burns slower. The carb saloon mixture and timing will be a useful guide, with vac advance operating, because the cylinder head etc is near identical.. But the PI cannot be leaned properly without encountering the pinking upon flooring the throttle: that lean spike. Running lean without advancing the spark wont improve consumption much. Because, for a lean mixture, the spark will come too late on standard TR6 disy, the flame ends up chasing the piston down the bore not pushing it properly. Peter For those wanting to try, set the AFR to 15, a typical crusie mixture for older engines, and see what happens to mpg when the vac capsule is connected to the throttle edge. Edited March 29, 2015 by Peter Cobbold Quote Link to post Share on other sites
Clarkey Posted March 29, 2015 Report Share Posted March 29, 2015 I get at least 30mpg on my PI even two up and all the gear needed for Le mans Quote Link to post Share on other sites
JohnG Posted March 29, 2015 Report Share Posted March 29, 2015 Peter Good morning I understand the basic link between mixture and ignition advance / retard For those wanting to try, set the AFR to 15, a typical crusie mixture for older engines, and see what happens to mpg when the vac capsule is connected to the throttle edge. AFR? Help a simple steam man Given that the ignition adjustment is simple, how is the MU adjusted? On my PI the vaccuum capsule (advance / retard?) is not connected. I assumed that this is the case for PI '6's Quote Link to post Share on other sites
peejay4A Posted March 29, 2015 Report Share Posted March 29, 2015 John, Before attacking the metering unit I would read and understand Technicalities Section L. If you don't although you might get lucky you risk a whole load of grief. The vacuum advance is not connected on PI cars. Quote Link to post Share on other sites
astontr6 Posted March 29, 2015 Report Share Posted March 29, 2015 John, Following on from what the 2 Pete's have said! Have you done a compression check? Have you done a vacuum check? Have you done an A/R check on the exhaust? The first 2 items have a major effect on the A/R mixture. Unfortunately TR PI's have to run rich by modern standards. Bruce. Quote Link to post Share on other sites
JohnG Posted March 29, 2015 Report Share Posted March 29, 2015 Bruce A/R? I know that, in full running condition, currently, hydrocarbons are up at 8000ppm whilst CO is within MOT emissions limits Compression test has been on the cards for a month or so, but, other things keep getting in the way, not least the need for a 2nd body to crank the engine. These are particularly rare in my family. The ones that do exist, always seem to have other vital things to do Apologies to Mike, I think there is some topic highjacking going on here I can start a new one, if needed Pete Regarding knowing what I am doing . . . . The Technicalities Section is a definate destination. Whether I understand what I am reading or not, is a different issue! Hence the 'idiots guide' request Quote Link to post Share on other sites
peejay4A Posted March 29, 2015 Report Share Posted March 29, 2015 There's no idiot's guide that I'm aware of John. That would be down to too many interactions between the various adjustments that can be made I imagine. Even a skim read of the Technicalities section will give you an idea of what you're in for. If you do make any adjustments, document them so you can go back however many steps you need to to get to a sensible situation. Quote Link to post Share on other sites
Peter Cobbold Posted March 29, 2015 Report Share Posted March 29, 2015 (edited) http://t2000.kvaleberg.org/t_pi.html#intro Edited March 29, 2015 by Peter Cobbold Quote Link to post Share on other sites
Cew Posted March 29, 2015 Report Share Posted March 29, 2015 Are your spark plugs showing a correct colour i.e a straw colour? If not then you can start looking for rich/lean mixture. My car regularly does 30+ on a run that you described in your original post,push on a bit though and it will drop quite dramatically,driving style is a big factor as are weather and traffic conditions. The Jaguar will also top 30mpg on a long run with the cruise control set at 80/85mph,pretty good for a 4ltr V8 auto,use the sport button and right foot and single figures are possible! Quote Link to post Share on other sites
keith1948 Posted March 29, 2015 Report Share Posted March 29, 2015 Just to make everyone gasp.... I have a TR4A with standard engine, tuning and overdrive. Fully laden with two people in it we got about 36mpg to Nice in the south of France and back over the Alps. Regularly get over 30mpg. Don't know how it does this. Not running lean or anything. Just before anyone says check your calculations we went to the Dordogne area with a fellow TR owner and his wife in their TR4A which had a race tuned engine. They used far more fuel than we did for the same journey. Keith c'est la vie! Quote Link to post Share on other sites
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