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You'll want a large quantity of wire and a Brother D610BT label maker that prints on heat shrink tubing.
Being able to print on heat shrink tubing is a nice touch when making harnesses, we have one of these: https://buyheatshrink.com/kroy-k4350-printer
We put clear heat shrink over the label heat shrink
Being able to print on heat shrink tubing is a nice touch when making harnesses, we have one of these: https://buyheatshrink.com/kroy-k4350-printer
We put clear heat shrink over the label heat shrink
High end! I'm intrigued by the "Bartender" software that comes with it. Custom straws?
I'd pay up for a machine that prints on both sides, since the printed side is always twisting out of view.
I invite people to play with the calculator linked above to explore the effects of aerodynamics. Definitely non-negligible at highway speeds in the context of EV range. I know, an engineer making calculators can really spoil the fun, but that's the way it goes.
My original comment about aerodynamics and drag was not meant to imply they are entirely negligible even at motorway speeds. It was in relation to the comment that improvements in vehicular aerodynamics were the sole cause of range increases in BEVs, which they are not.
Never heard the Ferrari V12 F1 engines in person, but I did hear the later 19,000 RPM V10's up close. Next time you find yourself standing next to a grand piano with the lid up, pluck the middle C strings; that's about how fast the pistons go up and down. …
From my time working with Honda, I have 2 very distinct memories of noise.
Back in the '70s we organised some special Honda Festivals at various race circuits around the country, allowing customers to actually ride/drive on the track. This was pretty groundbreaking at the time as there were no such things as track days back then and although obviously supervised, it was the first opportunity the public had to drive on the famous tracks. Anyway…
It was decided to bring over some special show vehicles for demonstration on track. One was the 1.5L V12 that I think had won an F1 race many years before. On arrival it was parked in our Training Workshop and a bunch of Japanese engineers who accompanied it set to work preparing it to run. Extraordinary looking engine with small diameter high pressure Fuel Injection hoses snaking all over it. Eventually they finished and simply started it up. This workshop was directly attached to the offices and the banshee shriek of this V12 being warmed up (never do that at tickover) soon had the entire office staff craning their necks around the door to see what on earth was going on. With 12 exhaust pipes like spaghetti, but short and simply exiting direct to atmosphere, in an enclosed building, the sound was painful. In fact I seem to recall the engineers wore ear muffs. We of course had no such luxury.
At around the same time, also for a Festival demonstration, they shipped in one of the RC166 race bikes. For those who don't know, this was an air cooled 250cc straight 6 Grand Prix racer that Mike Hailwood (and some others) rode.
In fact Mike was also going to ride the demo laps at Brands Hatch where that Festival was due to take place, but someone had to start it first. Unfortunately (Ha) our Race Team was unavailable and so myself and a colleague from the Training School were designated to perform this 'onerous' task and had to be taught how to start it - in that same workshop that had also seen the F1 V12 started.
Starting required a powered roller and 2 persons. One to hold the bars and operate the throttle and the other to lean over the back of the bike to keep the wheel in contact with the spinning roller. First of all the Japanese engineers demonstrated how to do it. Once it had fired up, warming it up between 10 and 12k rpm which horrified me and almost made my ears bleed. Then it was our turn and I was first on the rear wheel which meant literally leaning over the seat to put as much weight as possible on it while putting ones ears in close proximity to the 3 exhausts on that far side. The rollers spun, I leaned and the first pipe crackled, then another, then another and then the others chimed in and I was inches from the loud end of those megaphones while my colleague kept it revving above 10k rpm. Unnecessary I thought as I was sure it would actually tick over without any bother. Then it was my turn on the throttle.
With my colleague leaning on the seat, the rollers spun and it started up. I was grateful to be a little further from the noisy end and also let the revs drop to just over 1,000 rpm at which it ran quite happily and I was feeling very pleased with myself for proving it was possible and demonstrating this to the others. At which point one of the engineers rushed over and took over the twist-grip from me and again 'blipping' the throttle to keep it revving between 10 and 12k rpm. Gesticulating to me in no uncertain terms I was doing it wrong by letting it tickover.
After it stopped and we could again converse, I was told that it absolutely HAD to be warmed up between 10 and 12k rpm. It was NOT to be allowed to run slowly. Obviously I asked why. "Ah", they said. Then "no oil pump".
That little 6 cylinder 250 racer used no oil pump. Lubrication was entirely by splash and at less than 10k rpm, there was not enough. Splash that is. So letting it idle as I had demonstrated it could do, perfectly well, was a very bad idea and would result in it seizing rather rapidly. Oops.
So armed with the full knowledge of how to start it, we awaited the day of the Festival to start it up in pit lane at Brands Hatch for Mike (Hailwood) to ride a few laps. As it turned out, the Race Team miraculously found they could spare some people and they were determined that THEY would perform the start up. Ok, my ears were pleased. But on the day, my colleague and I were in pit lane watching from a safe distance as thousands crowded around the little gem of a bike. We grinned at each other, knowing what was coming and as it fired up, you've never seen a thousand people take 10 steps back so quickly.
So all in all a fascinating experience and something I will never forget.
For those who don't know, Mike Hailwood, brilliant rider and multiple motorcycle World Champion and who was instrumental in pulling a fellow F1 driver (think it was Niki Lauda) from his burning car (and saving his life) years later when Mike raced in F1, was finally killed while driving his car on a simple run to pick up some food for the family and someone in a truck/lorry did a U turn in the road right in front of Mike, killing him and I seem to recall his daughter also (but I'm not 100% on that last).
Some members on here have a Honda CBX which although 1,000cc is a direct descendent of that little 250, the CBX's design being overseen by Soichiro Iramajiri who designed the RC166. An air-cooled straight 6 with DOHC and 24 valves. Of relevance here is that Porsche had never been able to do this. They had been unable to manufacture such a cylinder head so their flat 12 racers of the time always had to employ water cooled heads (2 x 6 cylinder) despite wanting them to be air-cooled only. When Honda announced the CBX, Porsche were so keen to know how Honda were able to make such an intricate cylinder head, I believe they made a special request to Honda, asking how they had done it. I don't know the outcome, but I am absolutely sure Honda would have obliged.
Despite any manufacturing complexity, the CBX is a brilliantly simple and delightful engine to work on. Even now, 40 years later, I could probably rebuild one with my eyes closed. And yes, it makes a glorious sound and yes, I still have one. I'd love an RC166 as well, but I suspect close to a million for even a replica. Oh well.
Some Honda reminiscences, but with a Porsche link at the end. I hope it was of interest.
My original comment about aerodynamics and drag was not meant to imply they are entirely negligible even at motorway speeds. It was in relation to the comment that improvements in vehicular aerodynamics were the sole cause of range increases in BEVs, which they are not.
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The you misread my comment which was “Most EVs achieve their range because of improved aerodynamics. Convert a classic and you’ll need a lot more juice to achieve the same”
Didnt claim it was the sole cause of range increase, my point was that at speed it’s the largest factor impacting range. Convert a barn door to an EV such as a hummer and the range is seriously impacted using the same battery capacity, as is a classic car with poor CD which won’t achieve the same range of a slippery modern EV.
Knowing that would enable you to compare the torque it'll give you at the back wheels compared to the 928's V8 in each gear.
Hi Ken
1st gear 2.217 and final drive 3.5, what they call a "speed ratio" of 7.761
Motor max revs = 10,000rpm. They quote 105kw and 350Nm but I don't have power and torque graphs.
Tyre size is 215/55/17", so a rolling circumference of almost exactly 2.1 metres
By my calculations if motor at 10,000rpm, driveshaft rotating at 1288 rpm, or 21.47 rps.
And therefore 45.1 metres/second across the ground. Which equals 162km/h or the good old fashioned imperial ton. I think the car is software speed limited to 150km/h. So that gearing sounds correct.
Does that all sound right to you? I look forward to pulling the gearbox apart to see how lubrication would work if the thing is upside down.
I gather there's no oil pump and it's a simple splash (1.3 litres 75W90 ATF) I hope we just need to reverse the breather and drain.
Cheers
Stu
Knowing that would enable you to compare the torque it'll give you at the back wheels compared to the 928's V8 in each gear.
OK, part 2. Having just done the numbers for the puny MG motor, let's look at the Porsche's mighty 4.7l 300hp V8.
Now the donor car was originally a 3-speed automatic 928, so we might actually compare with that, rather than the manual box, which is actually quite tricky to get off the line smoothly.
3 speed auto : First gear is 2.306 and final drive 2.75, so total ratio of 6.34
5 speed manual : First gear 3.601 and final drive 2.75, so ratio of 9.903
And the Porsche motor can't match the 353Nm of the MG until it reaches 3000rpm, by which time it's doing 47 km/h in first gear (auto) or , and taken a lazy 3.6 second to get just that fast. Or if a 5 speed manual, 35 km/h in about 2.7 seconds.
At 2500rpm, the lock up speed of the torque converter at WOT, it's only pushing about 300-320 Nm.
So it would appear that the gearing, plus the flat torque curve of the EV motor - IMHO - are likely to give it an acceleration advantage at speeds up to 70-80 km/h over the automatic 928 and quite probably also over the manual box car at speeds up to 50-60 km/h.
I have plenty of petrol 928s here, so I really look forward to the real world drag race against them all. 3-speed, 4-speed and 5-speed!
Bring on 2024!
Knowing that would enable you to compare the torque it'll give you at the back wheels compared to the 928's V8 in each gear.
And a final footnote - the Porsche's tyre circumference is 1985mm, a little less than the 2099mm of the higher-profile but narrower tyres on the MG.
So that also works to the advantage of the EV-powered 928 in terms of rear wheel torque. I neglected that in my first calculation.
I think you need to also consider the effect of the torque converter off the line which will probably double the wheel torque. Comparing my EV and 928, I find the accelaration figures don't tell the whole story. When you stomp on the pedal the EV response feels instantaneous, a real world measure would be from when the driver decides to gun it and how quickly the car gets to the speed he/she wants.
I think you need to also consider the effect of the torque converter off the line which will probably double the wheel torque. Comparing my EV and 928, I find the accelaration figures don't tell the whole story. When you stomp on the pedal the EV response feels instantaneous, a real world measure would be from when the driver decides to gun it and how quickly the car gets to the speed he/she wants.
Absolutely right about the instant torque of the EV compared to an ICE. However, a torque converter doesn't really increase torque, apart from in some situations allowing the engine to rev higher (making more torque), so more to the rear wheels then if it was direct drive to that same ratio in the gearbox. But then there's the inefficiencies of a TC doing that so it all gets very complicated and simpler to ignore it, as if it was a manual car with those ratios.
Stu, we can ignore wheel sizes. They wouldn't be part of MG's claimed output figures and if we want to compare 928s (i.e. ICE vs EV) we can assume same wheel sizes.
I have the same figures for the Porsche gearing. This results in the following torque to the wheels:-
From the above it can be seen that the MG motor will put more torque to the rear wheels then a 4.5L 3 speed 928 in first gear at optimum rpm. So it WILL be quicker, even without factoring in the broad spread of torque from an electric motor.
A later 5L S4 fares better in this comparison as it 'can' put more torque to the wheels than the MG, but only in first and when the rpm is optimal for torque which almost never occurs. Once in second, even the S4 at optimal rpm cannot match the MG's torque . In truth, the way an electric motor produces max. torque instantly and over almost its entire speed range will likely make an MG powered 928 quicker off the line even than an S4.
So that makes using the MG motor rather appealing, however I have serious reservations about running it upside down. There are quite possibly special channels to catch splashed oil and direct it into e.g. bearings and when inverted, they will do no such thing. It would be of concern to me that trying this might amount to an extremely large can of worms.
Also, trying to adapt the existing wiring to fit into the 928 will I suspect end up being more effort than simply making a new harness where required and I hate to be disparaging, but the idea of having the MG's dash hidden in the glove box sounds dreadful (even if angled towards the driver). Ok perhaps for some boy racer's hot hatch with offensively loud exhaust, but not for a sophisticated GT like an electric 928 should be. However, that is JMO.
Putting the MG's dash in the 928's original binnacle would however be rather cool, even though it would no doubt offend the purists.
Not that I have any great love for Tesla, but I have a growing suspicion that going the Tesla route would be a much smaller headache.
For what it's worth, I entered some reasonable (?) values into my calculator (link above) for the MG's drivetrain placed into a 928. I could enter the low-speed 350 Nm torque, but could only guess on the high-rpm values (a simple two-line approximation is used - see the website for info about this).
It would appear that top speed will be limited by the gearing. At a 60 kW motor output, the model says you'd be going 174 kph at 11329 rpm. Note that the stated power of the motor (105 kW) is probably only for limited time. The motor I'm using in the Jaguar has as stated power of 120 kW, but that's a "peak" rating; the continuous rating is 60 kW. The only definition of "peak" I could get was that the inverter was good for 30 seconds at 120 kW. Other parts of a system can be limiting, such as the battery.
Predicted acceleration looks good to me, 6.2 s to 100 kph. Note the reported "theoretical" energy usage rate does NOT include all sorts of things.
The witty adage for engineering models like this one is "All models are wrong; some are useful." In other words, no need to tell me these predictions are wrong. Better input values would be welcome, however.
Those with the patience to read the full text accompanying the model on the website will be rewarded.
Absolutely right about the instant torque of the EV compared to an ICE. However, a torque converter doesn't really increase torque, apart from in some situations allowing the engine to rev higher (making more torque), so more to the rear wheels then if it was direct drive to that same ratio in the gearbox. But then there's the inefficiencies of a TC doing that so it all gets very complicated and simpler to ignore it, as if it was a manual car with those ratios.
Stu, we can ignore wheel sizes. They wouldn't be part of MG's claimed output figures and if we want to compare 928s (i.e. ICE vs EV) we can assume same wheel sizes.
I have the same figures for the Porsche gearing. This results in the following torque to the wheels:-
From the above it can be seen that the MG motor will put more torque to the rear wheels then a 4.5L 3 speed 928 in first gear at optimum rpm. So it WILL be quicker, even without factoring in the broad spread of torque from an electric motor.
A later 5L S4 fares better in this comparison as it 'can' put more torque to the wheels than the MG, but only in first and when the rpm is optimal for torque which almost never occurs. Once in second, even the S4 at optimal rpm cannot match the MG's torque . In truth, the way an electric motor produces max. torque instantly and over almost its entire speed range will likely make an MG powered 928 quicker off the line even than an S4.
So that makes using the MG motor rather appealing, however I have serious reservations about running it upside down. There are quite possibly special channels to catch splashed oil and direct it into e.g. bearings and when inverted, they will do no such thing. It would be of concern to me that trying this might amount to an extremely large can of worms.
Also, trying to adapt the existing wiring to fit into the 928 will I suspect end up being more effort than simply making a new harness where required and I hate to be disparaging, but the idea of having the MG's dash hidden in the glove box sounds dreadful (even if angled towards the driver). Ok perhaps for some boy racer's hot hatch with offensively loud exhaust, but not for a sophisticated GT like an electric 928 should be. However, that is JMO.
Putting the MG's dash in the 928's original binnacle would however be rather cool, even though it would no doubt offend the purists.
Not that I have any great love for Tesla, but I have a growing suspicion that going the Tesla route would be a much smaller headache.
Ken, thanks for preparing that. The EV may not provide full torque at low speeds. A few of the EVs I've driven lately actually use software to prevent full torque at launch. The MG4 Essence and BYD Dolphin gave a relaxed take-off but many AWD EVs like the Genesis, Polestar, Volvo cars and the MG4 XPower launched hilariously briskly. Tesla M3P is of course the benchmark - quite ridiculous. It's quite amazing how fast modern family cars are compared to the supercars of last century like the 928. I will try to find an opportunity to launch the MG ZS EV just to see if it's intentionally toned down at the hit of the throttle. They only quote 8.5 seconds 0-100km/h. Hopefully without the crashed bonnet flying up and breaking the already busted windscreen. Or maybe just video it, as no doubt there would be plenty of schadenfreude if I get showered in glass.
Another thing - indications are that the 928EV will weigh under 1400kg using the current MG based battery setup. Even with all the batteries in the front (I believe they will fit with a 3L x 2W x 3H layout) weight distribution is still close to 50/50. Much of what you would expect to find up front ends up in the back of the car - charger, invertor, 12V battery (but not in its original compartment), A/C, DCDC convertor, and of course integrated motor, gearbox/diff. From a handling viewpoint I would prefer something closer to 45F/55R by putting some of the batteries in the rear but splitting the battery box is of course a bit more work.
Regarding the gearbox/diff, it's a very simple design inside as far as I can tell. Matt and I look forward to pulling it apart. I'm expecting that we won't actually be would be rotating it about 135 degrees, so the relationship between input shaft and output is more or less retained, with the input shaft still sitting higher and not submerged. It may be that only the breather needs to be relocated. Of course first we need to test position it in the 928 to check the diff housing clears the crossmember without crazy driveshaft angles to the hubs.
One thing is clear - the mechanical side is the easy part. Electronics and communications will absorb all the time.
Thanks again for you input.
A lot of what I'm doing with this car will offend purists but fear not, as soon as we chatted about it, the binnacle in the glove box sounded a clunky idea to me too. It would be a shame not use the beautiful original instrument binnacle, repurposing various instruments using digital to analogue mapping of CAN messages. Fuel guage => range, water temp => motor temp, oil pressure => HV battery voltage, tacho => power/regen. Really it's just the speedo that would retain its original function. And for registration, I need to retain a lot of warning lights - simple things like the handbrake. I also need an interference proof non-GPS odometer and speedo too (so they work in tunnels, again a rego requirement). But the centre section of the MG cluster is quite important for all the warnings it can provide. Merging the function of the dash technologies I suspect will be a very difficult.
For what it's worth, I entered some reasonable (?) values into my calculator (link above) for the MG's drivetrain placed into a 928. I could enter the low-speed 350 Nm torque, but could only guess on the high-rpm values (a simple two-line approximation is used - see the website for info about this).
It would appear that top speed will be limited by the gearing. At a 60 kW motor output, the model says you'd be going 174 kph at 11329 rpm. Note that the stated power of the motor (105 kW) is probably only for limited time. The motor I'm using in the Jaguar has as stated power of 120 kW, but that's a "peak" rating; the continuous rating is 60 kW. The only definition of "peak" I could get was that the inverter was good for 30 seconds at 120 kW. Other parts of a system can be limiting, such as the battery.
Predicted acceleration looks good to me, 6.2 s to 100 kph. Note the reported "theoretical" energy usage rate does NOT include all sorts of things.
The witty adage for engineering models like this one is "All models are wrong; some are useful." In other words, no need to tell me these predictions are wrong. Better input values would be welcome, however.
Those with the patience to read the full text accompanying the model on the website will be rewarded.
That's really useful thank you. I think you're pretty close with your torque estimation too. And yes, continuous power will be a lot less than peak power. This will be a suburban car, not an autobahn crusher. My weight balance model is pointing to a total weight under 1400kg, which would be a fantastic goal. It's amazing how much all the ICE-based stuff weighs in total.
And I'm currently 79kg, but will be 75kg by Christmas and do the performance test in a pair of speedos if that helps.
12-14-2023, 01:50 PM
