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MG Midget and Sprite General - Aldon RR day out
| Just arrived back to dark and slightly damp Devon after a morning at Aldon Automotives for the RR day. Thanks to James, Dennis, the guys from Aldon and everyone else who was there. Some interesting runs and Blackie survived although with a new dizzy and leads reqd it might be a bit more money yet needed from SWMBO!!! Dave |
| Dave Price |
| Come on Dave we want to see your graph - how many horses !!! Any pics ? R. |
| richard boobier |
| the more I use it the more I can reccomend the 123 full electronic dissy, great response throughout the rev range particularly noticeable good pick up at motorway speeds I found last week I had an Aldon igniter head in my old dissy so new electronic at the top married to an old and probably worn dissy parts below make an ideal Xmas present from a loved one (and mine came with a set of HT leads free) have some fun and photoshop the graph - I did :) |
| N Atkins |
| Yes it was great to meet up with you all. Faces from the past and faces new. Dennis, James and Aldon gave us a super day out. I was not expecting much from the MGB for its bhp, but in fact it returned 86 which was excellent news. However, I am rather wandering if the recorded 140ish lb-ft torque was a tad enthusiatic considering the standard factory engine produces about 100 ft-lb. Anyhow apart from the engine idling rich, but correct when on power, it seems that the setup I had applied to the engine prior to coming was OK. Roly |
| Roly Alcock |
| Hey Roly, Singer Le Mans next year then! Neil PS Missed it this year. |
| Neil K |
| Richard - you seem to imply horses as a plural instead of horse!!! Well - the chaps tinkered with the carbs - well out of balance and adjusted idle etc so the screens were green re gases etc. what for it... . . . . . . . Max 59 - 38 at wheels at 3931 but as I had no idea anyway its 58 more than I thought!!! seems like the dizzy needs work to it and I seem to be getting through the oil so Mr L Slater et al may be getting some questions or the very pleasent Antony Cutler who I met today may be asked for info re K series!!! Dave |
| Dave Price |
| my first RR with this Spridget was 66 and 44 at the wheels, a few changes and many services later it's a few more different RR give different figures so you need to go back to same RR for comparision figures on the second RR with this Midget I didn't even bother with a print out as I could see the dials were well over reading Peter Burgess is my man, with his new rolling road, I don't expect to see much if any increase in the figures when I go back next year, might even show a small drop, who knows, as long as the car's set up best it can the actual maximum figures don't worry me |
| N Atkins |
| My thanks as well to the guys at Aldon and the organisers. Having initially said the graph looked just like the last one (and yes it does) they did a bit if tweaking and found another 4 horses in there, so the similar lines are all higher up the vertical axis whilst looking similar on the horizontal. I'm well pleased with the lower tick over and hopefully an improved mpg, sounds so much better as well. John 
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| John |
| To echo what the other guys have said; the Aldon guys looked after us well and gave everybody their time & help in equal dollops in a friendly yet professional manner. I enjoyed the day very much and would reccommend it to anyone. Special thanks to Dennis & James for organising the day. Not forgetting of course it was good to check out my car and find every thing in good health; 77@flywheel 59 @ wheels and good flat torque curve. Ian |
| Ian Webb '73 GAN5 |
| Dave I can recommend the 123 tune too. Fantastic piece of kit. Expensive, but nothing to wear so it should last a lifetime and can be set to any advance graph you like. Mine engine needed 40 degrees at 2000 revs and 32 at 4000. This is easy on the 123. Try to get that on weights and springs in a normal dizzy. Dave |
| Dave Brown |
| Yep fabulous day Ian just a point about your hydraulic hand brake forgot to ask As you are using the original lever did you disconnect the normal wire actuator and now simply have hydraulic? |
| Bob Turbo Midget England |
| Blooming heck Dave 40 degrees at 2000rpm, are you sure that is right??? All the engines I have ever had would have destroyed themselves almost instantly with such timing??? |
| Bob Turbo Midget England |
| Had a great morning at Aldon, I'm sorry that I couldn't around a bit longer but I had to be back in Cheltenham before lunchtime. I'm not sure if they fiddled with the tickover on mine or if the foot to the floor excercise has mucked something up but since coming away from them my tickouver has gone from just under 1000 rpm to 2500 rpm. I haven't had a chance to check it yet as the car went straight into the garage once I got back to London. Here is my printout for those whio are interested. 1bhp more than I was expecting. 
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| Gary & Gaps |
| Bob The standard handbrake mechanism is untouched, still completely as standard. Ian |
| Ian Webb '73 GAN5 |
| Please see attached the plot from Blackie. As a 'bog standard' 1275 does this ring bells with those who have a similiar model?? Dave |
| Dave Price |
| Dave: Don't forget to post your 'sheet. Ian: that's very creditable for a std 1275... would you tell us your secret(s)?! and post your sheet? Tim Dalton saw 194 bhp for his Kseries, some 13 up after fitting TBs... maybe I should bite the bullet and release the cheque book (but 'only' 155 lb-ft torque compared with 170 rumoured on another K...). I was there for the morning part of the session, and as usual there's a ton to learn about MG engines (from James and the very helpful Aldon crew) and their owners... Turbo Bob: would be great to see your sheet, too; must say the turbo installation very neat; loved the turned dash - very 20/30's! A |
| Anthony Cutler |
| Ant, that's odd. Dave's sheet was there last time I looked but now it's gone! |
| Gary & Gaps |
| Gents, Here's my sheet, scanned it this morning at work. The spec of the engine is: still 1275cc, maniflow LCB + twin box exhaust, K&N air filter, Vizard type flowing on the carbs & inlet manifold, head is just cleaned up, sharp edges deburred not opened up, standard compression ratio, all valves, pistons, crankshaft, rods, camshaft, are the originals for the 1973 engine, everything balanced as normal, rods and pistons have just a little smoothing out nothing extreme. I was more impressed by the torque curve than the power curve. Its done approx 70k miles so nice and loose, I think thats the secret Ian 
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| Ian Webb '73 GAN5 |
| Ian Interesting. I saw 72 bhp some years back at Aldon with cleaned up head & manifold, Vizard'd HS2, LCB, RC-40 etc on engine with around 80K (new shells but orig bore&pistons). I looked a little disappointed, but 'the man' said he'd expect around 60 bhp from std engine so I should see it in that light. Yours does even better! Were I to go the ASeries route again (don't panic! I'm talking about another Midget, not removing the K from BRB...) I'd definitely hone a few though thou further than the rebore to reduce friction... I'm a big believer in the 80/20 rule, e.g. small mods can each release some few hp easily and the next step in hp becomes increasingly expensive and so on. So my approach is release the easy hp before shelling out the £££s for diminishing returns. Can/would you share outline of mods to piston and rods? A |
| Anthony Cutler |
| Lets try again!!! Dave 
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| Dave Price |
| OK Ant here is mine So lets see a bit of A SERIES grunt!! LOL Here was the chart for basic running on low fuel pressure from fuel supplied by the cube. :) 
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| Robert (Bob) Midget Turbo |
| Then I showed him where the button was!!! I love it LOL :) 
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| Robert (Bob) Midget Turbo |
| Feeling a little sw*nky after the run I turned around to see the results Expecting 150/160 boy was I shocked!!! at 117!!! Sh1t what was wrong?? try again so I can see what is not right please mister?? Finally breathed a sigh of rlief on the next run when I could see boost pressure only reaching about 12psi somewhat less than 1 bar and a lot less than designed! Obviously my control gear is not reliable and needs attention but it is worth seeing on the power chart where the turbo stops at 12/13psi at 3800RPM at which point torque packs up rising. If that had continued to how it ought to be then power would be 160BHP at 5000rpm and torque would be approaching 200ftlbs But all that is speculation and next year hopefully will be the test. In the mean time Ant I will settle for 150ftlbs at 4000rpm! mate LOL. |
| Robert (Bob) Midget Turbo |
| Yes... 150 lb-ft is just over twice standard 1275, so the boost is working... will be interesting to see if you can extend the rev range... as you say, power will climb. AS it is, similar to a Kseries under around 4K or so. I have performance prediction (I hope this will format well when posted): PERFORMANCE COMPARISON ANALYSIS 1. A MG MIDGET STD 2. A MIDGET 1275 TURBO DVK Car Number 1 2 --------- --------- Time to Speed 0-30 mph.... 3.2 2.1 0-40 mph.... 5.7 3.6 0-50 mph.... 8.0 5.5 0-60 mph.... 11.9 6.8 0-70 mph.... 16.2 9.2 0-80 mph.... 22.8 11.4 0-90 mph.... 37.4 14.7 0-100 mph.... 21.2 Time to Distance 0-100 ft..... 3.6 3.2 0-500 ft..... 9.8 8.3 0-1320ft..... 18.4 15.3 @ mph .... 74.0 91.3 Top Speed.... 96 106 5-60 mph, 1st Gear Start... 11.8 7.8 30-50 mph 2nd Gear..... 4.2 2.0 3rd Gear..... 5.9 2.9 4th Gear..... 8.6 6.6 50-70 mph 2nd Gear..... 3rd Gear..... 7.7 3.2 4th Gear..... 9.9 3.7 Hope you this interesting; btw if you car has/had 5th gear with .82, top-speed would be 114 mph; with 4 spds, the top-speed is way past peak. I'd increase boost in small stages to avoid creating a grenade... 150 already v high; what you really want is this level of torque at higher revs. Have you considered that high boost temps could be the problem? Maybe air-rad not cooled enough by the blower on the road? Do you have air-temp gauge? Would be good to see boost pressure and temp vs. revs to see correlation. A |
| Anthony Cutler |
| My car does 0 - 1320ft in 15.5secs with a lot less power than a modified turbo midget! |
| Shawn |
| Hi Ant you seem to have misunderstood. I have been running the car at boosts above 1 bar for a good while now and it is not a problem. However for some reason the high boost part of the circuit decided to play up at that time and so a test could not be done. I am pretty happy about the extrapulation I suggested and hopefully next year will get it down on paper. A flat torque curve is fine but if you flatten the curve simply by reducing torque at higher revs then what was the point. An engine needs to be allowed to develop as much torque (and thus power) as possible irrespective if it is flat or not? |
| Robert (Bob) Midget Turbo |
| Surely with a 5 speed and a 3.9 diff 114mph is slightly on the pesimistic side. |
| Gary & Gaps |
| Sorry to bump this up again but what do you chaps think of the curves? The feedback from Aldon seems to have been wiped from my memory banks already!!! Dave 
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| Dave Price |
| Dave Your plots are very similar in shape to mine, which suggests the same standard camshaft, mine has a bit more power due to improved breathing but has otherwise standard but tweeked parts, (keeep in mind on my plot the dyno is not really reading anything until 2450rpm..whereas on your plot its reading much earlier from around 1900rpm) What sort of spec is the engine ? Assuming its all standard then you are just a tad on the low side for power. Ian |
| Ian Webb '73 GAN5 |
| I'd say... torque peaks at reasonable revs for std camshaft; the high value suggests good breathing / good compression. But torque falls away a little too quickly - engine would make more power if torque hung on a little later so power peaked at (say) 5K. If your breathing is good (and carbs giving OK mxture at top-end), I'd check the dissy to make sure it has increasing advance past 3K to a max of around 32 degrees total (static and mech advance added together; disconnect the vac advance) around 5K or so. (Mech advance gives max of around 13 dissy degrees which is 26 deg on the crank.) This check best done with strobe (like Turbo Bob is always endorsing!). If you never exceed 4.5K revs by much (road use) you could argue your engine is fine for purpose; maybe not for track-days and so on. A |
| Anthony Cutler |
| Dave let me try and help you understand just a little bit of power understanding. The torque line of your engine (the top one) is an indication of how much fuel/air is getting into the engine and being used to create the bang. The second line down or middle band is simply a multiplication of that torque multiplied by the RPM at which it occured and is power. It is the power at the flywheel. Going back to the torque curve the higher that is the maths dictate the higher the power will be. But more importantly, the longer that remains high the higher the power will be because again the maths will dictate torque multiplied by RPM = power so if torque remains constant but revs rise then so does power. To make the torque stay high for longer generally we use a hotter cam and that would be the effect of using a 276 or 286 or something hotter. Alternatively to get the value of torque further up the graph then perhaps porting the cylinder head would get more mixture into the cylinders causing a bigger bang and thus creating more torque and thus more BHP. We should look at our charts and understand that as the RPM increases then after optimum the power begins to fall. We should rightly assume from this that further revving will possibly be unwise and changing gear would put us back in the higher power area of our engine. All this is very simplistic but I have written many articles about this subject over countless years and each time I do I get more and more bogged down in detail. I hope this more simplistic approach has been of some benefit? |
| Bob Turbo Midget England |
| Good explanation Bob. It helps me understand the print-out much better. |
| Gary & Gaps |
| Dave here is my comparison from last year, this is what Bob means by saying <make the torque stay high for longer generally> Note the rev range and torque just keeps going with a highly ported gas flowed head and very free flowing exhaust and not to forget a small turbo strapped to the side! Yes well said Bob you have a very good way of explaining things, I know what I mean but just dont know how best to explain to other people. Should be fitting my intercooler over the winter, so next rolling road should be interesting. 
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| Rob Newt |
| Dave, I can thoroughly recommend 123 dissy to you and your SWMBO fully electronic no greasing or oiling good igntion leads are chep enough but if you're going 123 then the right angle dissy cap has push-on leads (not screw in cut end HT leads) treat yourselves to a visit to Mr Burgess to but a 123 and have it set up on his RR and a sandwich at the cafe service the car before the visit and subject to your carb wear you don't then need to mess with settings just drive the car Bob, am I reading Dave's print out correctly(?) about 95 lbft at about 2,800 rpm and 59 bhp at fly and 39 bhp at wheels at 3,931 rpm |
| Nigel Atkins |
| Hi Rob I was hoping you would post your chart. After comparison I note your curves are a little behind mine but certainly your boost goes on longer You can see on my chart that the boost flattens out at about 4000RPM. I noted that was about 13 psi if that. As I tried to explain had it been controlling correctly the boost would have continued to climb for another 40% so the torque figure would have continued to rise. I am disappointed that it did not do that and would like to have fiddled with it to make it work correctly. However I was the second to last on the rollers and it was getting very late so had no time. And there is always next year. :) What however I wanted to compare however was the fact that I knew you had a fully moddied head and so I have been keen to leave mine as standard, which it is which frankly amazes me that I can develop power earlier. I assume my turbo is boosting a little before yours, maybe? Hope you will be able to attend next year mate and I will keep my head standard. Not much of a problem as it frightens me to death as it is LOL. I am pleased that has proved useful as I said I must have written 8 articles describing power and torque understanding and at the finish of each I have thought well if that is simple I am a dutchman!!! |
| Robert (Bob) Midget Turbo |
| Thanks for the feedback above. Aldon said that the dizzy was worn and needs sorting, I am glad to hear that the engine itself looks fine regards power etc - thats all I was after at this stage. I think some thought s on a new dizzy are needed and may go for a traditional type at present due to costs and go from there. Will keep you all posted. dave |
| Dave Price |
| Bob, Thanks for putting into words the feeling in/on the seat. " -- understand that as the RPM increases then after optimum the power begins to fall. We should rightly assume from this that further revving will possibly be unwise and changing gear would put us back in the higher power area of our engine." I had a lively tuned 750 bonneville engine, and you could feel the additional acceleration come in and drop off as you got to and past that optimum rev range you talk about. I used to love keeping it in the range just so I could blast past people unexpectedly. |
| Lawrence Slater |
| >>changing gear would put us back in the higher power area of our engine. But don't forget, when you change up (e.g. from 2nd to 3rd), the torque multiplier in the box goes from 1.9 to 1.3... so choosing the optimum is a little more complicated than first sight. I have a program that uses torque curve (with rpm) and gearbox ratios to suggest change-up points. So using example above, for optimum accleration you should change up when the torque in higher gear (but at lower revs; remember x1.3) is higher than torque in present gear (higher revs, torque dropping off; but x1.9). For std Midget (3.9 diff; max power 5.8K, max torque 3K), they are: - 6.5K - 6.3K - 6.1K For David Price's curves (and 3.9 diff), it suggests: - 4.9k - 4.8k - 4.3k And for Bob (3.9 again; with boost): - 5.7k - 5.4k - 4.9k HTH A |
| Anthony Cutler |
This thread was discussed between 19/11/2011 and 26/11/2011
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