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MG Midget and Sprite Technical - EFI
| Has anyone tried Electronic Fuel Injection for the Spridget 1275 engine? Or other A series engine? I'm interested in converting a '69 Sprite to fuel injection for improvements in gas mileage. IF you've tried this, does it improve gas mileage? Bruce H (twinCarb 69 Sprite) |
| B C Hamper |
| Its not really possiable because of the siameise head....some have done it to a degree....the best way to do it is get a 7port speedwell head....There are some interseting articals here and about ...cant find them right off where they are using sleeves and re-porting to make a "D" shaped port...but I guess it screws up the airflow even more.... I also found an artical along ways back where a guy split the head horizantilay put in new ports modified water jacks using the 2 backend fresse plugs on the engine and taped a hole on the backside of the head and put a tube to connect...not sure what he did about the oil ways but welded it back togather....I never did hear if it worked or not...Im guessing not cause the artical was pulled and I never heard anyting agian. but its something to play with in the back of your mind. BTW....DId you show john your fenders yet...what did he say....are you still going to keep them as is??? prop |
| Prop |
| Thanks for the EFI comments. Guess I'll put that idea to rest for a while! I really wanted to get better mpg in my trips around town and thought fuel injection would be the answer. I'm sticking with the fender arrangement as is; one turn signal up and one down. It's a minor thing and gives the car character. How many crosseyed Spridgets are there? Winky lives on! For those who don't know what Prop is taking about, see photo! Bruce H (Winky the crosseyed Sprite)  |
| B C Hamper |
| Bruce, I looked your car over pretty good at Spridget 50 and never caught that. It's such a beautiful car that I never noticed any differances and I doubt very many people ever would unless you or Prop point it out. Rik |
| Rik Hogan |
| Actually stefan has the same situation....Im not sure if he changed it or not. But for gas millage, Id say put a 5 speed in the easist way to increase by 25% prop |
| Prop |
| I do not know if EFI would increase mileage to a large extent, but it can certainly be done. It is not a simple matter to do port injection, but throttle body injection should prove no more difficult than putting a throttle body on any other engine. |
| Trevor-Jessie |
| Later UK Minis (from around '93?) used EFI... should be worth investigating. A |
| Anthony |
| EFI on the A-series engine with std head is possible. The mini's have had a spi (single point) mpi (multi/twin point) from 1993/4 up til 2000 and it worked fine. The reason it was used in the mini's was the improvement in the exhaust department (eu inviromental rules) and with it came a little improvement in gas mileage. So go for the 5 speed for better gas mileage. the spi/mpi system's are so expensive you can get a lot of fuel for that. |
| o Könemann |
| I run a supercharged EFI 1275. I use the Megasquirt to control as well ignition as fuel. If tou buy yourself the HIF 44 manifold, you can bolt on a Thtottle Body Injection unit as a alternative for the HIF44, You need a return fuel line, the Megasquirt, a wideband afr sensor, a high pressure fuel pump and some patience. |
| arnold |
| http://www.kmnet.demon.co.uk/arnold/ I don't agree with fellow Dutchman. A late Mini S(ingle) P(oint) I(njection) unit, including everthing will cost you 100-200,- euro. You might go for that, but you cannot tune it anymore as you use the stock ECU controler and you need ignition control as well then (I am not fully sure about that for the SPI units) |
| Arnold |
| if you want to tune forget about the stock ecu that is a hopeles piece of junk. |
| o Könemann |
| I didnt realise the heads off a 1993/4 mini would fit an A-series 1275 from the early 70's in order to do multi port injection....Do the heads have 7 or 8 ports.., that would be so cool cause I could trash the EFI system and run 4 SU carbs, one for each clyinder ...NOW that would be cool....any website or source to find info for making that kind of conversion??? As to a single point injection system...the question is ...WHY??? after all the HIFF 44 is way more tunable as to AFR...(air/fuel/ratio) then a computer chip prop |
| Prop |
| "HIFF 44 is way more tunable as to AFR...(air/fuel/ratio) then a computer chip" True if you had a convenient way of logging the throttle position and needle height. But even then you can not file the needle while driving down the road, then add material back if it goes too rich. SU may be infinitely tuneable, but they are not as easy to tune as a computerized SPI. |
| Trevor-Jessie |
| AH ......And there lies the classic debate..... Old school DONE it all old farts ""Verses"" Computer KNOW it all young kids yeah you make a good arguement...but Id rather trust my fingers and ears then a computer chip....thats why I keep all my money in the matress instead of banks LOL prop |
| Prop |
| Prop calm down 5 port heads all the way to the end of the production run shame huh? you want four carbs you need this seen on a "BMC Works Mini" at Silverstone Classics weekend in July four ports in four ports out!  |
| Bill |
| Oh that is SO COOL ....adds to the cool factor by a multiple of 12 easily....I love it... NOW I got to get a 7-8 port head... Im in love... prop |
| Prop |
| 8 ports on that one here's the exhaust end too  |
| Bill |
| many ways to skin that cat too They must have spent years trying to get over the 5 port head at BMC comps This was individual mechanical injection on each port I think I'd be happy with the four Amal carbs myself I spent rather a lot of happy time looking at the BMC specials on display I really ought to have been watching racing happening just a few hundred yards away...  |
| Bill |
| I wonder why no one ever bought the rights and started making the mowag 8 port heads....as an aftermarket head...afterall someone took the risk by making the aluminum heads ... granted the mowag head needs its own cam cause of the way the valves are set up...but hay why not just set up an aftermarket mowag head based on the A series valve train design what car did those Mowag 8 port heads originally go on to??? prop |
| Prop |
| Prop MOWOG is the official logo of BMC, I will not bore you with the technical reason for the name but I bettcha someone does, wait for it! Anyway the search for the 8 port cylinder head has been ongoing for as many years as the Mini has been on the road. About 50 years in fact. In that time we have had many incarnations of the idea, sadly none of them have been successful. The main reasons being reliability and the need for major engine modifications to make it fit. I suspect the one shown on the Mini by Bill probably need a different cam and other block mods. The latest efforts are trying to adapt the BMW head will tell if this becomes a worthwhile effort :-) To answer your question this head was never used on a standard car |
| Bob (robert) Midget Turbo |
| I'm sure you are right Bob I seem to remember Dave Gilbert had a sooper cam operating his Arden head with its Amals I was very interested to see both of those comps Minis at The Silverstone Classics though, and some of the other fabulous machinery. All of the good stuff wasnt in the Paddock, by any means |
| Bill |
| Ive seen the head face, It would definatly require a diffreant cam and things...the valves are set up as EI EI EI EI instead of EI IE EI IE Im not much of a big fan of the BMW head conversion beyound that of a modification marvel....granted Im sure it screams aand does wonders, but to me it goes beyound "The spirit" of the A-Seris 1275... esentially its a low rev limit V-tec engine with a distubtor.... which I absoutly love a true Vtec engine...if lucas and kimberly were still building midgets today no doulbt they would be using Vtec plants....to me it dosnt make any sense to make a frankinstine engine of a Vtec top with a weaker bottom half 1275(compared to a full V-tec) To me the 7-8 port A-series heads are in range of the "spirit" but if you want a Vtec then save a few dollar and go a full Vtec, and reap the rewards of a safe running 9xxx rpm engine prop |
| Prop |
| why the hell go for an 8 port?!?!???!? when there is a 7 port available! http://www.minisport.com/acatalog/Mini_7_Port_Cylinder_Heads.html pro's? -std exhaust patern (no down side siamees port is more eficient than the 4 seperate) -std cams -std rocker gear so it is a bolt on piece 8 ports never are the have different valve positions so you would have to make a special cam and a special exhaust which is expensive and difficult |
| o Könemann |
| 8 ports heads are available for long time from Elder company (http://business.fortunecity.com/lerner/445/head.htm), sold also via MiniMania and other retailer. Not cheap but... And also EFI shouldn’t be a to hard challenge (http://www.emeraldm3d.com/em_projects_Aseries.html) |
| toni |
| Please note that I ordered a 7 port head on 5th Jan this year and was continually told that the casting would be ready....for the next 6 months! This is why I am going down the BMW route. There is some custom MS code to run siamesed ports with a great deal of sucess but this is not an 'elegant' solution. Trust me, ever since BobT got his EFI running I have been looking at the different ways of EFI'ing a 1275. Please feel free to get in touch off the bbs as I do not get internet access at work so am not on here as much as I used to. |
| Toby Anscombe |
| thanks Ok and toni.....wow pricy uh. seems odd that they are offering a 10% summer discount on those 7 port heads but they still havent delivered tobys head 8 months later and counting... prop |
| Prop |
| A bit off topic but have few questions for Arnold. 1. First about fuel pump, do you have double pumps solution (SU pump to swirl pot and from there on hi pressure pump)? Where is located hi pressure pump? 2. Then air delivery, do you have some kind of duct to deliver fresh air, or you engine use hot under bonnet air? 3. Spark distribution goes via distributor or you have installed coil pack? If yes, are you using toothed trigger wheel? 4. Are you using TPS signal or MAP signal? 5. How much boost is producing SC? 6. Your bypass valve release air to atmosphere or is re-circulating? What is idea of re-circulating air, it is already hot because of compression, so why would be good to send it again to SC? 7.You installed throttle in front of SC – does position of throttle affect response of engine? toni |
| toni |
| 1. First about fuel pump, do you have double pumps solution (SU pump to swirl pot and from there on hi pressure pump)? Where is located hi pressure pump? Bosch 3 bar EFI pump located where the stock one, near the rear axle 2. Then air delivery, do you have some kind of duct to deliver fresh air, or you engine use hot under bonnet air? I placed the airfilter right next to the rad justr behind the hole where the air hose for the heater (was) located 3. Spark distribution goes via distributor or you have installed coil pack? If yes, are you using toothed trigger wheel? I use Crane Fireball XR700 ign, dizzy is locked and spark is controlled by the Megasquirt 4. Are you using TPS signal or MAP signal? Both, Megasuirt uses both sensors, MAP sensor is fitted into the Megasuirt, TPS is located on the throttle body 5. How much boost is producing SC? At the moment (still tuning) about 0,3-0,4 bar), I do have a smaller pulley will raise till about 0,5 bar 6. Your bypass valve release air to atmosphere or is re-circulating? What is idea of re-circulating air, it is already hot because of compression, so why would be good to send it again to SC? I have recirculating valve, this is needed because otherwise I would get 'false air'. The idea of this valve is to let the blower spin free when cruising. Before I fitted this valve the blower would heat up REALLY, now it stays pretty cold. A hot blower heats up the inlet air (which is bad). A MUST 7.You installed throttle in front of SC – does position of throttle affect response of engine? Throttle was behind the blower, but this resulted in a throttle valve being blown open, so the engine would decelerate anymore. Also I did not want fuel to travel through the blower... So I had to. Throttle response is perfect, decelerating is still a bit a problem, when revving without driving Arnold |
| Arnold |
| I must add that the throttle might be placed upstream now that I use a bypass valve |
| arnold |
Regard fuel pump, do you hava filter also in front of pump? Don't you have problem with fuel delivery without swirl pot? |
| toni |
| yes filter, no swirlpot (no need) |
| arnold |
This thread was discussed between 02/08/2008 and 07/08/2008
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