We have a couple of old supercharged MG TDs (1950 & 1951) running the old single SU carb. Air/fuel ratio control is not precise whatsoever and erratic very lean on acceleration, deceleration and at highway speeds.
I've looked at MS over the years and have contemplated the addition of Megasquirt to one engine this winter. I say addition because I can keep the carb intact and switch on a fuel pump to go back to carb at any time in case of fuel injection problems (have 2 electric fuel pumps plumbed in and switches under the dash... for reserve fuel and as a backup pump since the old SU pumps used mechanical points and fail frequently). I have a pretty good idea of what directions to go, but would like to poll this forum for good suggestions.
Here's the nuts & bolts of the cars in question- currently running 1250CC engine with 4 lbs boost, but the one of this discussion will bump up to 1450cc and maybe up to 10 lbs boost. We're still only looking at modest 75 hp. This is primarily for street running, but they've been out on Michigan International Speedway, and will be back there in the future, as well as road racing courses, but no serious racing. Intention is to run a single injector, and set up as a single cylinder engine so there's fuel injected sequenced for each ignition pulse. Engine sports electronic ignition, so the Megasquirt will only be expected to deal with air/fuel. Already has a narrow band O2 sensor for the air/fuel ratio gauge.
All suggestions welcomed.
MG 1950 supercharged candidate for simple Megasquirt
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
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Re: MG 1950 supercharged candidate for simple Megasquirt
Just a couple of general points. I had an XPAG engine in a TC fitted with a supercharger and single SU many years ago, and it ran very well. So it can be done.
SU fuel pumps are reliable if in good condition - and most spares are still being made. One worthwhile mod is to fit a diode across the points which extends their life even further. Or the points can be replaced with an electronic switch.
Personally I'd go for the 1500cc overbore (will likely need liners), ditch the supercharger, used twin SUs modified to injection, and mapped ignition. With a little head work you could easily exceed your 75bhp target. And keep it looking pretty standard.
However, that's just a personal preference.
But if you do go for single point injection with the charger I'd also consider mapping the ignition.
SU fuel pumps are reliable if in good condition - and most spares are still being made. One worthwhile mod is to fit a diode across the points which extends their life even further. Or the points can be replaced with an electronic switch.
Personally I'd go for the 1500cc overbore (will likely need liners), ditch the supercharger, used twin SUs modified to injection, and mapped ignition. With a little head work you could easily exceed your 75bhp target. And keep it looking pretty standard.
However, that's just a personal preference.
But if you do go for single point injection with the charger I'd also consider mapping the ignition.Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
Re: MG 1950 supercharged candidate for simple Megasquirt
I have attempted several times over the years and on several vehicles to use a narrowband O2 to tune a carb system.
When they say narrowband they mean narrowand. so narrow as to be useless. When I build my MS I am gunna run a wideband!!
When they say narrowband they mean narrowand. so narrow as to be useless. When I build my MS I am gunna run a wideband!!