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MG Midget and Sprite Technical - Best location for ECU - EFI 1275

This thread is directed to the small universe (constellation?) of midget owners who have fuel-injected their Midgets (stock motors or K-series), or have pondered the task.

I am about to put my harness together, so need to determine the length of the wires from the ECU plugs (GM ECU) to the motor. I was going to put the ECU in the passenger footwell, but when the heater is on full blast I am afraid the ECU will get cooked. The air coming out is HOT. Computers don't like heat.

If I had a Bugeye, it'd be simple: just put the thing on the outside of the footwell, and it'd be easily accessed with the bonnet swung up. Not so easy with a Midget. The trunk seems too far, and atop the little package shelf behind the seats would subject it to shock from plunking down grocery bags, my briefcase, etc. I guess under the front of the passenger seat might be okay... any ideas?

Joel.
JM Young

Ive always seen them passanger side top of foot well inside the engine compartment... just have to move stuff around is all till it fits

Granted ... I havent seen many of them

Prop
Prop and the Blackhole Midget

put mine on the parcel shelf. K Midget omex ecu
J Austerfield

Prop - I really don't want to put it inside the engine compartment; too bloody hot. Also, I'm using that space for relays and the updated fuse block, which comes in two sizes. I will probably use the smaller one: http://www.amazon.com/Blue-Sea-Systems-Blade-Block/dp/B000THQ0CQ/ref=sr_1_2?ie=UTF8&qid=1409012474&sr=8-2&keywords=blue+sea+fuse+block. Thank you, though.

J. Austerfield - when you say 'parcel shelf,' do you mean the little one just under the dash, or what I was calling the 'package shelf' behind the seats? I hadn't had the former installed for a while, and having slipped it into place just now, that might be the ticket. I think it might shield the unit from the hot air pouring out of the lower vent.

Incidentally, the project will be on the web sometime this fall or winter (the way things are going at work). The website, dormant for now, is www.buildingabettermousetrap.net

Thanks again.
JM Young

If its an automotive ecu it'll cope with heat just fine.

Mines in the top of the engine bay just tucked under the wing above the fuse box and has shown no ill effects at all.

Have seen them both on the bulkhead where the heater is and on the "knee shelf" in front of the passenger. Both are OK.
Rob Armstrong

Sorry, the little one just under the dash/knee shelf
J Austerfield

I have a Rover Vitesse, the V8 kind, I mention this because the lower power models were carb and only the higher power models got the ECU - so in effect it was an after thought.

Think of an angled plate for the passenger to put their feet on - then put the ECU on the underside of the plate.

Malc
Malc Gilliver

- slightly off topic warning -

I've got a metal under dash shelf that would easily take the weight of a piece of electronic equipment, either on the shelf or hanging from it, such as what we used to call a "stereo" or "radio"

my heater gets hot and particular with the footwell flap open under the metal shelf in the passenger footwell

do others think that if a CD player "stereo" is fitted hanging from the shelf in line with the full heat it would continue to operate properly?

Nigel Atkins

Duno Nigel. Both the "modern" cars we've had have suffered from heat soak through the centre console stopping the CD player from working after about 2.5 hours. Don't have any music in the midget.

Didn't range rovers have the ecu under the seat? Perfect for soaking water up when offroading. Wherever you put it it'd be handy to be able to take it out for security.
Rob Armstrong

Wow, you guys are great - thanks for all the advice.

Rob - it is an old, OBD-I GM ECU, so I hear you about toughness. I guess I'm just defaulting to what GM did, which is typically mount them somewhere in the passenger compartment. Maybe they did that for some reason other than heat, and I'm just being over-cautious.

As for the location you suggest, I'm thinking of using up that space with the newest Blue Seas Systems split-bus fuse block (out this winter--forget the above-listed smaller one) and some relays. Here's the nifty fuse block, http://www.bluesea.com/products/5032/ST_Blade_Split_Bus_Fuse_Block

HOWEVER, your suggestion makes me think about making some longer, aluminum 'J' brackets with rubber pads that would effectively dangle the ECU down behind the wing. That would cure the lack of Bug Eye-esque access to a unit in that locale, and at least keep it out of the prop wash (no offense intended, Prop).

Might not be too hot down in that space, as I could put it a fair ways down and perhaps take advantage of the thermocline. Would make for a nice, short harness, too. I seem to remember shoving a shop vac hose down there to remove some piñon nut shells when I rescued the thing from behind the Sandia Moutains (huntavirus concerns in these parts). So, perhaps there's plenty of room.

Do you have a photo of your install? Is yours a K-Midget or 1275?

***

J Austerfield - thanks for the clarification. I just reinstalled mine after repairing a tear with woodworking glue (worked wonderfully), and was thinking of putting the ECU there. Alas, I might not have sufficient room to stash my Walther PPK, bow tie, and driving gloves...

***

Malc - I think the plate idea is very tempting, but I am 6'2" and my brothers are taller, so every inch in the footwells, longitudinally speaking, is precious. I actually moved my dimmer switch from the driver's side floor, so I can stretch out my clutch leg on longer drives. BIG difference in comfort.

***

Nigel - I have the original Midget radio box that mounts ahead of the shift lever. I actually thought of stuffing the ECU behind that, especially as the positive earth radio won't work anymore, but then there'd be no room for a 'new' stereo--as I will always call those things.

***

All - I'll be posting numerous pages on the dormant, 'better mousetrap' website this winter, or whenever I finally get the experiment done, and will put a heads-up on this BB. It will have a step-by-step install with photos, parts list PDF download, etc. The newly released novel has slowed me down a bit: http://www.amazon.com/Lion-Door-Joel-Matthew-Young-ebook/dp/B00JMV2Y9S

T.T.F.N. - Joel
JM Young

Hi Joel,

I have a Megasquirt ECU bolted up to the underside of the passenger side (UK) footwell where you originally suggested. Previous to this I had a Megajolt ECU in the same place, this was necessary as I had changed the engine to a Vauxhall XE engine. In changing the engine it brought the exhaust out of the engine onto that side of the car, but I ran that setup for over 2 years on the road and on multiple track days without issue.

The reason for the Megasquirt was the decision to turbocharge the XE engine, this has SIGNIFICANTLY increased under bonnet temperatures. The ECU is still mounted in the same place, and I have no issues from the heat entering through the heater flap with the ECU. The heater is long gone, to make room for the engine, but the air from the engine bay is far hotter, than a heater could ever manage if left open, as the exhaust is now within inches of it and at speed the airflow works it's way through there.

In the attached photo I have highlighted the bolts to show the location of the Megasquirt under the panel. One thing I will say though, is that I have had to make an aluminium heat shield (not shown in image) to protect the smaller fusebox you see in the image and the relay as well as the brakeline which passes very close to my home made exhaust manifold. The plastic coating on the female spade terminals was actually melting around the fusebox terminals prior to this!!!

So basically I don't think the ECU will be too much issue inside the footwell, even with the heater on maximum. A 1990 Honda accord has the ECU under the passengers feet with the heater fan outlet directly above it, and these suffer no issue because of it. But be very wary of under bonnet temperatures and the locality of wiring, fuseboxes and relays with a direct line of sight to your exhaust manifold.

Hope this is of some use.

David

D Prince

Hi, David.

Yes - your experience is indeed helpful, and the photo is greatly appreciated.

I was just rethinking my behind-the-wing idea on the way home today, as I watched a moronic NM driver sail through a red light and spin a Toyota around 360 degrees. The Tercel's concave, right-hand wing made me reconsider the relative safety of the passenger footwell!

Luckily from the standpoint of under bonnet heat, I've fought off the urge to swap engines, though I did pull a Suzuki Samari tranny from the local yard the other day, which mates up nicely to the 100hp Swift 1.3L DOC http://www.ado13.com/dohczuke/dohc.htm, as I'm sure you know. So, for now the Maniflow LCB header is opposite the passenger footwell on my North American-spec '67 1275.

Very well - I think I've settled on the upper footwell for the ECU. Suspending it from the sheet metal above the package shelf will at least leave room for a ham sandwich. Served warm, naturally.

Thanks again.

Joel.
JM Young

Joel,

Another thought ...what about behind the passanger side dash its self.... might be a little but it might be wortha look, the only thing behind it is the wiring harness ...so there should be some good gaps of space

Also.. if you convert the radio to a plug and go smartphone... that would free up alot of space in the radio consel


Yes. I love that susuki set up, if I went that direction id do 4) SU hs1 carbs / or amel carbs and a ford eids crank crank trigger ignition system ... I think that would be so much easier to set up as well as a space savor under the bonnet to make everything fit nicer

Prop
Prop and the Blackhole Midget

Prop,

Thanks for the suggestion. I fiddled around with that location last night, and these old GM OBD-I ECUs are too long in one dimension for that configuration. They're considerably longer than a Megasquirt, for instance.

David's suggested location, if you look at his picture, is about as close as you can get to a behind-the-dash installation, and these GM ECUs are pretty flat, only about 1.5" tall, so they don't take up much knee room. I think the top of the footwell, as far toward the dash as possible, looks like the best bet.

Huh - I had never thought of ditching the idea of a separate stereo unit altogether. Aesthetically, I'd have to figure out what would go in those holes for the knobs and dial. They do make USB and MP3 player plugs, for sure, and maybe the 'slot' for the dial could somehow accommodate a smart phone. Let me ponder that. I think the GM ECU would fit back there absent any stereo guts. Hmmm...

Ah, yes, the Swift motor. It's the smallest DOHC at or above the size of the 1275 I have yet to encounter, and with 100hp out of the box, as it were. Actually, now that I have the tranny, my main problem is finding a good used engine in the USA, or via one of those importers. I have looked exhaustively, and the only importer who purported to have one wanted $1,100. Ridiculous - and without the OEM ECU and harness! A complete engine at the local pull-n-pay is $250 (no alternator but with manifolds), a harness is $28, and an ECU is $36. I just can't see paying nearly three times that. The pull-n-pays out of state won't leave their offices to inspect a Swift and see whether it's got the DOHC engine, and a single trip to see for myself would cost what I'd pay for the engine.

My other problem is, well, my blushing bride. She L-O-V-E-S the sound of the 1275--something about performing a heart transplant on a perfectly healthy patient. Also, she finds it fascinating and uniquely satisfying that I might successfully fuel inject the lump with no mapping adjustments (yes - that is the goal of the 'better mousetrap' EFI conversion).

I'm not resisting those positions too hard, as the only solution to her quandary that I can come up with is to buy a second Spridget for purposes of the engine swap. "Don't throw me in the briar patch, Brer Fox." Also, she really wants a classic Mini, and would like that fuel-injected, too. So, the 'global' solution is to get (or build--she's handy with a nail gun) a pad with a free-standing garage at least the size of the homo sapiens quarters. I think the evening she nodded thoughtfully in response to that suggestion was when I proposed to her. Go figure.

Joel.
JM Young

I'd put it under the seat. Safe and cool
tim
T Dafforn

Tim,

That's an option I hadn't considered. I will check it out. Obviously, it would have to be as far forward as possible, due to the diaphragm-style seat.

Thanks for the suggestion.

Joel.

JM Young

Joel

This is where my stereo and my Emerald ECU on my K-series Midget went. Pic taken in the middle of wiring it all up.

I wouldn't put it under the seat - could be painful on landing if you get air over a jump...

http://i72.photobucket.com/albums/i178/lloydiemac/IMG_0025_zps1a81894e.jpg

Cheers, Lloyd
L McInally

Hi Joel. Mines a K series conversion and there is plenty of pics on www.kmidget.com.robsmidget.co.uk.
Rob Armstrong

Lloyd,

Ah... this is the location Prop must have been referencing. I misunderstood, imagining he was talking about behind the dash over the package shelf. Cool, I'll scope this location out tomorrow as well. Thanks for posting the picture.

If I get air over a jump! In New Mexico, the city streets are so rough that it's all I can do to keep my butt in the seat and head away from the hood bows. And to think I was going to use my book royalties to emigrate to the UK and enjoy your superior roads... :)

Rob,

Thanks very much. This is kind of like Christmas, getting all these cool pics. One of the two videos on the home page of 'better mousetrap.net' when it's reactivated will be a 0-60 mph of the internally stock 1275 with the EFI setup and Maniflow LCB as the only mods. I'm sure it will be a modest improvement, but an interesting experiment, nonetheless. Any idea what a non wheel-spinning 0-60 time is for your K?

Joel.
JM Young

Joel,

There is a efi system already made for the 1275, its on a 1990s era, but rhe problem is, its not very good...I want to say those were a single point injection

I think the real problem is the simese head design was just never quite right for efi

I know others have done this, but it takes alot of re-mapping... its not a plug and play set up.

What is it your hoping to gain by going efi

On the susuki engine... wow, I had no idea, I thought those were as common as ants to a pie eatting contest...I think GM used the same susuki engine in there geo metros soit might be a good idea to research the suski engine and see where else it was used

Prop
Prop and the Blackhole Midget

With the amount of work and expense of doing an efi

What about rebuilding the engine pretty much stock except for some high quality pistons and installing a bmw super charger blower to it....if your girl loves the sound of the 1275, she will probably go orgasmic hostile when she hears the cork screws pump some serious pressure into the engine for a good 100 -125hp

I doulbt it would be all that much more expensive then converting a 40year old engine into efi.

Prop
Prop and the Blackhole Midget

Prop,

Sorry - I had done a thread on why EFI in 2011. http://www.mg-cars.net/mg-midget-sprite-technical-bbs/fuel-injection-for-the-a-series-2011021303053527555.htm Got lots of great feedback and questions--including from you, if memory serves.

Short version is I'm not doing it for increased power, though I expect ~10% increase due to the usual mixture and ignition benefits of a good EFI system, plus improved charge flow speed from the intake I've dreamed up, plus the Maniflow LCB on the other end. Really, though, it's about drivability at high/variable altitude, and the engineering challenge.

As for cost versus installing a supercharger, I don't think it's comparable--and my goal is different, as I've said. My preferred route to super-duper power is an engine swap, like David, Lloyd, et al., and that's going to be on another car. The present Jenny keeps the 1275. As you'll see when my website is up later this year or early next, my DIY EFI setup is roughly $800 with mostly used parts, closer to $1,700 with mostly new parts. Easy to reproduce no matter where you live.

As for fuel and ignition mapping, that's the challenge I wanted to overcome--but we'll see. Doing a bunch of math and scribbling notes is one thing; firing her up and running up a long hill without burning a piston is quite another. As for details, please wait until I finish the website, which explains everything in great detail with lots of pics.

On the Suzuki engine availability - the particular Swift GTI twin-cam used in the 'Bugzuki' conversion I linked to above, the G13B, is very hard to find in the states. Tons of single cam versions and later (heavier) twin cams out there, but this extremely compact and light DOHC 100hp 1.3L was only used on a handful of models for a few years. I've been trolling for a while, and they're tough to find in the U.S. The one importer who had one on the dock last year wanted more than a grand. As I've said, the multi-state pull-n-pay with an outlet in ABQ wants $250 for any engine they stock. I'm going to bide my time.

Joel.
JM Young

It should be an interesting build, im certianly looking forward to following its progress


Will it be a single point injection system or a multipoint injection

Being that your doing efi and if you go the single point direction, it might be worth a look into a small turbo, it wouldnt be that hard or extra expence id think, esp is good used
Are you planning on using a mega squirt system?

I wonder if you couldnt get the same benifits for an up hill moutian climb using an pair of SU HS 4 carbs... they certianly breather better and you could re needle them for more air and then add more restriction to the venture of the carb

Just thinking off the top of my head....if im thinking correctly you want more air and less fuel and a faster charge at the elevated altidudes

Prop
Prop and the Blackhole Midget

Another thought for dealing with high altitude that would be cheap.and easy

An old persons oxgen tank... you could easily splice it into the intake manifold and have NOS valve set up for turning it on and off and callabration....that would certianly give you the extra air you need to fight a thin atmospher in a mountainous region

Prop
Prop and the Blackhole Midget

Whoops, seems like the link I put is a weird amalgamation of www.kmidget.com and www.robsmidget.co.uk. I blame my phone. Still, you seem to have worked it out. I've only ever done 2 full bore starts because Ive still got std half shafts and I'd like to keep them in one bit, but I timed the second one at about 8 seconds. Can't get straight line wheelspin in the dry now with the 185 tyres on.
Rob Armstrong

Prop,

Yes, throttle body fuel injection is the easiest way to avoid charge-robbing, and what I plan to do. As I was telling Rob above, I'll initially be using an old GM OBD-I ECU. If I can't make it work, then I'll likely switch to a Megasquirt, since they are preconfigured to use the same GM sensors and IAC stepper motor that I will already have installed.

Really don't want a turbo or supercharger. Again, my aim is seamless operation regardless of altitude or ambient temp.


Rob,

I think you should indeed blame your 'smart' phone for the amalgamated linkage situation type thing. I blame mine for all kinds of things.

Yes - I've settled on a variation of J. Austerfield's location--that is, under the parcel shelf, as I like keeping that space free for gloves, iPads, etc. I whipped up some brackets this morning ($15 including mounting screws and locknuts) that suspend the ECU and diagnostic port nicely underneath the shelf (image attached below).

It goes far enough back to be invisible unless you crane your neck to see under the shelf, and when you do, all you see is an aluminum strip with the port at one end. Had I mounted it all the way back, there would be limited room for my size 13 shoes.

Eight seconds is pretty snappy. I have to confess that one reason I want to build the second, Suzuki-powered Midget is to put my fiancé in her place (politely, of course). Her stock, turbocharged Volvo C30 does 0-60 in just over 6 seconds, and she's likes to make me eat her dust up the onramps. I had forgotten about the half-shaft concern. Ah, well. I'll cross the bridge when I come to it.

Thanks again.

Joel.

JM Young

Joel

That will look very sharp

Another thought I had, I wonder if you cant just gut the carbs out ... namely the floats and jets and configure the injectors into the bottom of the carbs, that way it still containes the loom of an su carb, without looking like its efi, and the air is still controled by the butterfly this way you dont have anything extra to work around

Prop
Prop and the Blackhole Midget

Prop,

Yes - that is what Rick Patton does: http://www.pattonmachine.com/TBI-Main.htm. He does not have a kit for HS2s, however (the TPS gave him fits), and his setup requires data-logging and retuning of the chip via the post--mine will not, at least in theory. Also, his solution is not aimed at performance--mine is.

Again, I'll be posting elaborate pics, info, and test results (too much to reproduce here) on the website whenever I can find the time to finish the project. This winter, I would hope--assuming the darned thing actually runs. I'll post a link on this forum when that happens, so you can surf the site.

Joel.
JM Young

Joel/Prop

Just got my K back together after a rebuild - the engine ran at 190bhp odd before the recent work (upgrading pistons, rods and liners). I threw a fair bit of cash at the transmission so it wouldn't break.

I've owned the car for 21 years and have restored it twice and wanted it to be the best it can be now I can afford to spend money on it. The next person who restores/modifies it will be my 6 year old son (or maybe my 5 year old daughter!).

Just shaking it all down, but foot 'slipped' off the clutch at the lights this evening - just lit up the rear tyres, sat down and effed-off down the road!

It probably does 0-60 in something around 5 seconds and is completely bonkers, but looks bog standard from the outside.

http://i72.photobucket.com/albums/i178/lloydiemac/IMG_1202_zpse9939590.jpg

In terms of reliable and value for money bang for buck the only way to go is K-series. If you're staying A-series based then choose two from three - fast, cheap, reliable...
L McInally

Well, bog standard-ish apart from ride-height and 14" wheels...
L McInally

L,

Very nice, and well.done, that photo could be a calader shot easily

Prop
Prop and the Blackhole Midget

Lloyd,

Wow. Five seconds is very quick. I'd be able to give my girlfriend's C30 a lesson in manners. Hmmm...

My '67 sits rather like yours--in the weeds, that is--and I replaced the wire wheel axle and stubs so I could mount minilites. Striking resemblance, but rrrred in my case and with the 'toothy' 'sixties grill, as in the image attached to my above email.

I will definitely consider the Rover K option, but I'd have to ship a motor (and possibly a trans) across the pond. That's one reason why I've been looking at the Suzuki G13B, which does occasionally surface in U.S. wrecking yards. And I've already got a serviceable Samurai tranny in the garage somewhere.

Until next time...

Joel.
JM Young

thing is, with the K series cars, it's not just about the 0-60, but the 30-70 overtaking and anything flat out in second gear, or indeed third sometimes, is bordering on lunacy. Mine 'only' has about 110 hp and is still capable of extremely rapid cross country runs.

good luck with finding one over there though!
Rob Armstrong

You're right Rob - I'm not that bothered completely nailing it off the line on the road all the time even with (supposedly) bullet proof transmission - harshest way to treat everything. Overtaking and accelerating out of corners is pretty devastating though and where it really shines.

As you can probably tell I'm loving it! It is laugh out loud bonkers.
L McInally

Rob and Lloyd,

Makes good sense. I didn't mean to give the impression that I am intent on building a drag-racer (after tackling the present, A-series EFI project). I focused on 0-60 only because it's a relatively easy way to measure performance without running afoul of the United States' low speed limits and overzealous police.

I like what Lloyd said about bang for the buck mated to reliability and, I assume with a fuel-injected K-series, drivability. I just can't see pouring $3K into a hot-rod, carbureted A-series, when I can spend less and get not only more power, but greater drivability.

As I've said in the earlier string to which I linked above, a daily trip in New Mexico can mean a 5,000 ft. variation in elevation and ~50 degree swing in ambient temperature. So, the 'controlled leak' OEM intake system, or for that matter any carburetor setup, just doesn't cut it.


Lloyd,

Yes - I can tell you are loving it, and when one "cast[s] a cold eye on life, on death" as it's presently unfolding around this shrinking world of ours, what could be more important than finding a benign source of "laugh out loud bonkers" enjoyment?

Case in point. I emerged from the elevator (I think you call them a 'lift') into the parking garage ('car park') recently, to find a 5'11" blonde in a designer business suit standing next to my Jenny. She was smiling and nodding to herself, and raised her eyebrows as I walked over and prepared to slip into my red Midget. I'm 6'3".

"Every time I see your car, it makes me smile," she said, returning her attention to the low-slung, topless red machine separating us. "Can you really fit into that thing?"

I hesitated for a beat, suppressed a smile, and nodded. "It takes practice, but, yeah, I can get in there."

She bit her lip, clinked her ring against her stainless steel coffee thermos a few times, then dropped her briefcase behind the passenger seat and looked me in the eyes. "Prove it."

I didn't bill many hours that day, but, man, what a ride.


Prop,

Here's a link to the promotion on the book you were interested in: http://www.amazon.com/Lion-Door-Joel-Matthew-Young-ebook/dp/B00JMV2Y9S

Have a lovely weekend, gentlemen.

Joel.
JM Young

Joel

Another thought might be th mazda rotory engine I think they call it a 13b

The thing that makes it tough now here in the states is the lack of small engine rear wheel.drive cars over the past 10-15 years, its surprising how many cars are now front wheel automatics

That high price tag for the swift engine isnt looking to bad anymore

Prop
Prop and the Blackhole Midget

This thread was discussed between 24/08/2014 and 12/09/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.