Ade-TR4 Posted May 27, 2014 Report Share Posted May 27, 2014 Edited... But just think - 60DCOEs... BRRRRRRRRRRUUUUUMMMMMMMMMMMM! Quote Link to post Share on other sites
Paul Harvey Posted June 27, 2014 Author Report Share Posted June 27, 2014 (edited) OK - the results are in and attached. Black line is the best result we could get previously with 45DCOE Webers (with 34mm chokes) Yellow line is with 42DCOE fitted by me and jets guesstimated by Stuart (with 34mm chokes) Red (top) line is the final result after muchos trials and changes on Pete Burgess rolling road In all 3 cases it is the same engine & same rolling road - only the carbs were changed Summary - improved power and torque across the full rev range Huge improvement to power at idle and low revs (not fully shown on chart) Longer power band a higher revs with less drop off and now willing to rev happily to 6,000 rpm Indications are the mpg will also be significantly improved (based on a very flat air/fuel mixture profile at optimum levels) Peter Burgess did not expect to achieve these results from a relatively standard 4 pot TR engine Some of the changes to jetting and ignition timing were counter intuitive His conclusion is that these Webers are perfectly matched to the engine's characteristics in a way that cannot be pre-determined Basically, very efficient fuel delivery and atomisation across the full range Happy customer. Bloody good value rolling road. Long live Webers Please note I was not looking for the highest power - I wanted smooth instant response at all throttle openings This car now flies and gives me exactly the fast road vehicle I was looking for Edited June 27, 2014 by Paul Harvey Quote Link to post Share on other sites
Motorsport Mickey Posted June 27, 2014 Report Share Posted June 27, 2014 Good stab at the internals by Stuart, having seen what the 42s give over the 45s through the range I think Stuart will be tempted to stick with his 40s. Mick Richards Quote Link to post Share on other sites
Paul Harvey Posted June 28, 2014 Author Report Share Posted June 28, 2014 http://www.ebay.com/itm/TRIUMPH-Pair-NOS-Weber-Carbs-40DCOE18-w-NOS-Cannon-8809-Intake-Manifolds-/271532483337?pt=Vintage_Car_Truck_Parts_Accessories&hash=item3f3898e309 This looks like the set up Ade is using successfully Great price for NOS gear ready to bolt-on Quote Link to post Share on other sites
Don H. Posted June 28, 2014 Report Share Posted June 28, 2014 Paul, if I'm reading your data correctly, the best results are about +5% horsepower and +4% torque over your lowest (which I'm assuming is baseline). Probably mathematically significant, but how would you judge the payoff for the cost and effort involved? Seems like a lotta work for the gain looking at the numbers. Perhaps driving the car is a different experience? Quote Link to post Share on other sites
graeme Posted June 28, 2014 Report Share Posted June 28, 2014 Paul, Good result, maybe there is a case for the NSF to get some 42s remanufactured? I need to dust down my 40s and get them refitted. Cheers Graeme Quote Link to post Share on other sites
Paul Harvey Posted June 28, 2014 Author Report Share Posted June 28, 2014 The gain is very noticeable on the road - low down power and pick-up is instantly stronger Top-end 'urge' is noticeably better Strangely, cabin resonance around the dreaded 3,000 rpm mark is also very much reduced The curve print out only shows the basic summary facts The rolling road allows you to look at many other variables in real time, all of which have been improved There seems no downside from the swap - not even absolute top end power where I would have expected to lose a bit from the smaller carbs Whether the change is financially justified is another matter - I suspect fuel economy will be improved, but I never check that so I won't be able to tell you The engine just seems 'happier' and so am I Which is what it is all about :D PS. I suspect 40DCOE carbs would give similar results and I think those with 34mm chokes are probably the right choice for all but race and track TRs (and certainly for engines with smaller than 89mm pistons) It would be very interesting to bolt Ade's 40's onto my engine and see what the results were as a direct comparison on the same engine & same rolling road That might be cheaper than producing a batch of new 42's Quote Link to post Share on other sites
Motorsport Mickey Posted June 28, 2014 Report Share Posted June 28, 2014 That's a plan...Ade...err. Mick Richards Quote Link to post Share on other sites
Ade-TR4 Posted June 30, 2014 Report Share Posted June 30, 2014 I'd be interested too, but it probably wouldn't stop me grabbing the next set of 42DCOEs that pass my way... I think the rolling road charges would be rather prohibitive too! Anyone used RE Performance in Bury (M/Cr) for weber setup? They did my SUs a few years back and were pretty good. Cheers Ade Quote Link to post Share on other sites
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