Ever think about replacing the factory fuel injection with some classic SU carburetors? Well, you have come to the right place.
One of our message board regulars had that same question, and we know a guy who did that very swap: Norman Garrett, one of the main engineers on the original Miata. We pinged Norman, and he explained the …
I've often thought a set up like the pic above would be the perfect swap for an MGB. Especially if you sourced one of the square, ribbed rocker covers from and Escort or Protege, then mill off the words and replace with the classic MG Octagon.
In reply to Adrian_Thompson :
I like it!!
In reply to Knurled. :
It gets better. My ultimate fantasy, scrub that, let's call it a daydream instead! Anyway, my 'daydream' was to use the SU dash pot dome to hid an injector and use MS to run it so it looks like carbs, but is in fact FI. Not sure how MS would like only two injectors running split port intakes thought.
Adrian_Thompson said:In reply to Knurled. :
It gets better. My ultimate fantasy, scrub that, let's call it a daydream instead! Anyway, my 'daydream' was to use the SU dash pot dome to hid an injector and use MS to run it so it looks like carbs, but is in fact FI. Not sure how MS would like only two injectors running split port intakes thought.
Eh, it wouldn't care. It would be like dual TBI units or a single ITB feeding a 4-cylinder. Things just don't happen that quickly on a domestic motor where the timing of that would make a noticeable difference on that type of fuel injection.
MS wouldn't be able to do it, not without custom code, and I don't know how well it would work. You'd either starve the second cylinder in the firing order or overfuel the first, or maybe vice-versa.
I know Subaru didn't bother trying to do port efi with single port engines. The XT and Turbo EA82s had two intake ports per head.
Adrian_Thompson said:In reply to Knurled. :
It gets better. My ultimate fantasy, scrub that, let's call it a daydream instead! Anyway, my 'daydream' was to use the SU dash pot dome to hid an injector and use MS to run it so it looks like carbs, but is in fact FI. Not sure how MS would like only two injectors running split port intakes thought.
SU and Zenith Stromberg using our Bespoke Adaptors
Systems for SU H2, H4, H6, H8
Stromberg CD150 and CD175With our bespoke adaptors you can easily convert your existing SU or Stromberg equipped vehicles to fuel injection.
These adaptors are our own unique design and fit between the inlet manifold and existing carburettor providing a simple and almost " original look " method of mounting the fuel injectors.
Using these adaptors in conjunction with our kits virtually any vehicle currently fitted with these carburettors can be converted to fuel injection.
In reply to Adrian_Thompson :
Hiding FI injection inside SU bodies has been done on a '75 TR6. I believe it was Rick Patton that did it. I believe he also supplied the setup to Bob Danielson.
http://pattonmachine.com/TBI-Main.htm
http://tr6.danielsonfamily.org/index.htm
For the full British Car Experience, why not just use bits of the Lucas fuel injection from a TR5? 
I researched it a lot, adding two SUs with injectors to a 4 cylinder, thinking about doing my B20 that way. Either you need a trick manifold, which do exist for some applications, or use the SUs as throttle bodies and add port injectors.
This seems like fun if you hadn't earlier in life contemplated self harm after having to actually deal with SU carbs on a regular basis.
With that same idea, why not go all out with a 4bbl carb! :)
I personally would use a pair of Keihin Flat Slides, granted it doesn't look British but being the best carbs ever made they would offer an advantage.
I used Hitachi SU carbs on my race car from 1992 until around 2007 and found them very user friendly. I only ever made minor adjustments to them based on weather conditions in att,to to get the last couple of horsepower. If it had been a street car I seriously doubt I would have bothered.
In my "tuning the BMC A-series engine" book by David Vizard, he tests SU carbs against Weber DCOE and finds the hp difference between the two very negligible. Like "error in the dyno" small.
SU carbs are actually very simple and easy to tune. What takes forever to figure out is that they are all worn out a couple of years after leaving the factory and hence can't be tuned because they leak air all over the place.
More recently, setting the float levels has become an issue because the chinesium parts do not work as described in the manual and fuel levels in the jets do not end up where they need to be.
ShawnG said:In my "tuning the BMC A-series engine" book by David Vizard, he tests SU carbs against Weber DCOE and finds the hp difference between the two very negligible. Like "error in the dyno" small.
That just says the bottleneck is elsewhere.
On the other hand, I read an interesting article about port design that used the reflection wave from the first IVC event in a port to supercharge the second intake port. You wouldn't be able to do that with DCOEs, I don't think. I really wish the article had pictures...
SU canoes?
In reply to alfadriver (Forum Supporter) :
I am frankly surprised that nobody has made the "constant depression" joke yet
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