Graze Posted November 26, 2015 Report Share Posted November 26, 2015 Well today is the day I finally got my rebuilt TR4 running the way I want it to the last piece of the puzzle (in this case) was the fitting of dual 40mm Mikuni carbs to the new (1000 mile old) high spec motor The motor was the last one built by a guy called Ted Davis who has lived Triumphs most of his life here in Brisbane and in his last years specialised in building wet liner high performance engines for Targa Tasmania cars & other nutters (like me). Unfortunately Ted got very ill half way through the process of building my engine and passed away at the end of September so hasnt seen the end product. But i reckon he built a pretty good motor. specs Moldex steel billet crank, cryogenically treated 14lb flywheel balanced rods, cryogenically treated 89mm pistons & liners fro Ken Gillanders in the states facet fuel pump Wizard Cooling Aluminium radiator ceramic coated dual 2 into 1 extractors uprated water pump high output oil pump ported & flowed TR4A head custom Tighe fast road cam roller rockers electronic rev limiter (6500 revs) fiuel pressure limiter inertia cutout switch Mikuni 40mm slide carbies so attached is the dyno print out with the Strombergs vs the Mikunis for anyone interested Nothing else was changed 94hp at the wheels on the Strombergs, 106 with the mikunis, but the real difference in the 40 miles Ive done in it tonight is the torque band which stays about 20-40ft/lb higher than previously from4500 to 6000 revs I just cant wait to get it on the track or a twisty mountain road where that torque and free revving will be magic putting aside the investment in the whole motor rebuild, the Mikunis cost $1000 & bolt straight on, the rolling road including fitting & tuning the mikunis (& a little fettling of new linkages) cost $800 - so about 900quid all up in your money for a 12-13% power & performance increase not for everyone i know but enough to keep me smiling for a long time Graze 151126 - TR4 dyno.pdf Quote Link to post Share on other sites
RogerH Posted November 26, 2015 Report Share Posted November 26, 2015 Heavens Graze, that makes my rebuild look like a moped engine. I hope it does all you want it too - it sounds rather good. Roger Quote Link to post Share on other sites
Motorsport Mickey Posted November 26, 2015 Report Share Posted November 26, 2015 Confused now,...I always understood that normally because of the maths involved in calculating the hp after measuring the torque the torque and hp lines will cross at 5252 rpm, not just one engine but ALL engines that exceed the 5252 revs area. Sometimes I've seen graphs that don't show this and normally you can explain it by examining the scale on one side of the graph to the other where they show other information ie scale on left 275 scale on right 300 which misleadingly reduces the revs area where the line cross, however if you reference both the scales and redo the maths then they resume the link of 5252 rpm crossing (where graphs are concerned the 5252 area can "wander" about maybe a couple of hundred revs due to the graphics). However I can't see on this graph where there could be this problem, torque is shown in lb ft and I'm slightly mystified why it doesn't work, any ideas ? Mick Richards Quote Link to post Share on other sites
Graze Posted November 26, 2015 Author Report Share Posted November 26, 2015 thanks Roger Mick i dont know anything about the 5252 issue sorry - hope someone else can advise Graeme Quote Link to post Share on other sites
monty Posted November 26, 2015 Report Share Posted November 26, 2015 Well, I am confused as my TR4 with similar tune but with twin Webers gives a much lower torque but a better HP of 113.4 @ 4800 rpm? Am I missing something? Also, I thought that if you up the cylinders/liners to 89mm then the capacity will rise. The capacity shown on the notes show only 2100 cc! I am on 86mm pistons/liners which I think gives around 2168cc? Cheers. Quote Link to post Share on other sites
Graze Posted November 27, 2015 Author Report Share Posted November 27, 2015 monty you are right about the capacity they just inputted the original 2.1L - it should be 2.4L different cam and or different dyno might explain the power & torque differences? Graeme Quote Link to post Share on other sites
McMuttley Posted November 27, 2015 Report Share Posted November 27, 2015 G, with a spec like that, no wonder you are called 'Mr Spender'. Look forward to the video (with sound track) Quote Link to post Share on other sites
Motorsport Mickey Posted November 27, 2015 Report Share Posted November 27, 2015 monty you are right about the capacity they just inputted the original 2.1L - it should be 2.4L different cam and or different dyno might explain the power & torque differences? Graeme Nope, whatever the camshaft or the dyno the magical formulae says that ALL engines that can exceed 5252 will show graphs where the hp and torque ( lb ft) cross over at 5252. Check it out on the web, try this for an intro into it. http://trust-me-im-an-engineer.kinja.com/why-do-horsepower-and-torque-cross-at-5-252-rpm-1650651680 Loads of information on it, it's a function of the torque being measured and the hp being calculated from it by the revs. As I said sometimes where different sides of the same graph are used for different engines or cams for comparison it's one of the ways I always compare looking for the crossover to be in that same rev area, a quickcheck to make sure of like for like comparison. ie: As long as figures are lb ft and the rest of the info is scaled correctly the power and torque will always cross over at 5252, it's the maths, that's why it's puzzling me, I can't see why these don't ? Mick Richards Quote Link to post Share on other sites
MichaelH Posted November 27, 2015 Report Share Posted November 27, 2015 Looked back at the dyno figures on my car and the Torque /HP cross over at 5252 Gee I wish I had 300ft/lbs torque my car is only slightly more than half that!! old saying "BHP sells engines Torque wins races" Michael Quote Link to post Share on other sites
Ragtag Posted November 27, 2015 Report Share Posted November 27, 2015 (edited) Mick, you are correct. HP = Torque (Ft/Lbs) x Revs Divided by 5252. The lines cross because 5252/5252 =1 Rolling roads don't measure horsepower, they measure torque (turning force) and calculate HP from that. Edit: Just realised I have simply repeated the info contained in your link!!! Edited November 28, 2015 by Ragtag Quote Link to post Share on other sites
Graze Posted November 27, 2015 Author Report Share Posted November 27, 2015 Mick I'll go talk to the Dyno guys next week and see if I can get an explanation Graze Quote Link to post Share on other sites
monty Posted November 28, 2015 Report Share Posted November 28, 2015 Looked back at the dyno figures on my car and the Torque /HP cross over at 5252Gee I wish I had 300ft/lbs torque my car is only slightly more than half that!! old saying "BHP sells engines Torque wins races" Michael[/quote Looked back at the dyno figures on my car and the Torque /HP cross over at 5252Gee I wish I had 300ft/lbs torque my car is only slightly more than half that!! old saying "BHP sells engines Torque wins races" Michael Yes Michael, 160 at best with 113.4hp, both @ the wheels on a well respected dyno. Cheers. Quote Link to post Share on other sites
saggy Posted November 28, 2015 Report Share Posted November 28, 2015 Torque 337 ????????????? Cosworth figures! My injected aftermarket mapped and dynoed five litre V8 only did 338 Quote Link to post Share on other sites
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