Fuel injection of A Series in Practical Classics magazine

Post by **paulhumphries** » Tue Jan 01, 2008 4:46 pm

In case people haven't already seen Practical Classics is covering the conversion of an Austin A40 to fuel injection using late model Mini parts.
The articles can be seen in last months and current issues (Jan & Feb 2008)

Paul Humphries

Post by **bmcecosse** » Tue Jan 01, 2008 4:49 pm

Crikey - most Mini folks are desperate to convert their injection Mini engines back to carbs !! Easy enough with the SPi - not so easy with the MPi.
The alternative - which does get some following - is Megasquirt which includes fully mapable injection and ignition and can give good results, although it's not cheap!

Post by **paulhumphries** » Tue Jan 01, 2008 5:00 pm

I THINK they are using a SPi system but I don' know anything about the Mini to be able to identify the parts one way or another.
I haven't read last months article yet but this months says rolling road shows brake horsepower at wheels up 22% but slight decrease in torque so adjustment needed to improve fueling at lower revs.

Paul Humphries.

Post by **MoggyTech** » Tue Jan 01, 2008 7:05 pm

Yup read the article and decided the reason I like the Moggy is the simplicity of it's design. I don't really want an ECU and another dozen or so 'modern' components just waiting to go wrong.

Likely to make insurance company jump up and down as well, and insists on better brakes. Big tuning is like a tube of Pringles, once you pop, you can't stop.

Post by **bmcecosse** » Tue Jan 01, 2008 7:12 pm

The Mini ecu is completely non adjustable - which is why Mini folks want away from it! You don't say what size engine they are converting - but SPi Mini engines made no more BHP than the carb models. Any power increase will just be down to easier air flow into the engine - which can be more easily arranged by fitting a larger carb ! It's not called 'Pratical Classics' for nothing!

Post by **minor_hickup** » Wed Jan 02, 2008 12:25 pm

I was more interested to read about how a chap fuelled his supercharged 1380cc mini engine using K-jetronic injection in PPC. It was scant on details though and I'm assuming he used a 7 or 8 port head. Could you use two injectors for one port? If this is possible it seems a very easily tuneable and cheap way of fuelling a heavily moddified or blown engine.

Post by **Orkney** » Wed Jan 02, 2008 12:27 pm

Could you use two injectors for one port?

Isn't that whats commonly called multipoint injection on a lot of modern cars?

Post by **MoggyTech** » Wed Jan 02, 2008 1:01 pm

Orkney wrote:
Could you use two injectors for one port?
Isn't that whats commonly called multipoint injection on a lot of modern cars?

Not quite. Multipoint injection usually just means an injector for each cylinder that injects fuel at just the right time for that cylinders intake stroke. Singlepoint injection is really just a fancy carb. Mpi injects fuel right onto the inlet valve, while Spi just squirts fuel into the inlet manifold.

Post by **jonathon** » Wed Jan 02, 2008 1:08 pm

I thought most mini injection ideas are now based on Bike systems. SPI was and still is a complete waste of space, so go mpi and fully mappable if anything. Omex is our prefered ECU supplier.

Post by **Orkney** » Wed Jan 02, 2008 1:43 pm

Ah i was thinking efi one injector per cylinder, multipoint 2 per cyl

Post by **minor_hickup** » Wed Jan 02, 2008 10:23 pm

So does anyone think feeding one port from two injectors (bearing in mind they are constantly fuelled) would be an acceptable way to run injection.? It seems from the picture of the car in question it is using a standard head.

Post by **eastona** » Wed Jan 02, 2008 10:32 pm

why? seems a little pointless, better off spending on other mods.

Post by **jonathon** » Wed Jan 02, 2008 11:14 pm

Twin injectors are often used on highly modified engines, to increase the amount and spray pattern of an increased fuel supply.

Post by **minor_hickup** » Thu Jan 03, 2008 12:19 pm

eastona wrote:why? seems a little pointless, better off spending on other mods.

I see what you're saying, but its been used and I was wondering how it had been done. Perhaps an answer to Picky's fuelling problems? I hear its cheap as chips to buy a K-jet system.

Post by **MoggyTech** » Thu Jan 03, 2008 2:16 pm

Well the final results are in after the 2nd part of the PC article. It uses an ECU by Camens EMS. They got a 22% increase in BHP at the wheels, but not until the 3,400 RPM powerband (5%) and not hitting 22% till 4,500 RPM

The car was an Austin A40

Oh and they managed to get less torque at sensible revs due to having to tweek the fuel system to get smooth running. They then discovered that better brakes are needed, wow what a surprise. The words "Two Short Planks" spring to mind.

Total waste of time and money. Who wants to drive an Austin A40 at 4,200 RPM to get the extra horses working? Mildly tuned head, better camshaft, bigger carb and better exhaust would do the same if not better.

PC Mag is like a car with no brakes, going downhill rapidly, and about to lose another subscription

Post by **chickenjohn** » Thu Jan 03, 2008 3:19 pm

At 4500RPM with an A series engine you are ready to change up a gear. Seems completely pointless to me, unless there was a huge fuel consumption benefit. Like MT, one of the (many) reasons I was drawn to the Minor was simplicity- including the SU carb. Oh and torquey power delivery.

That magazine has gone downhill so much in recent years I don't buy it anymore. I now only read my old copies from 2003 or before and glance at the latest in the supermarket. Classic Practical classic issues before they started featuring rubbish 80's hatchbacks.

Post by **minor_hickup** » Thu Jan 03, 2008 3:41 pm

I haven't got the copy with the second part yet. However I'm sure it was done as an engineering exercise. It sort of goes with the idea of enjoying and modifying cars for use in the modern day world. Personally I wouldn't have bothered, the idea of using old mini parts and all that effort just for less maintenance does nothing for me. EFI for fuelling a performance engine is far more interesting, but thats what PPC is for! It does seem Practical classics is moving forward in no particular direction and upsetting both the purists and the people looking more open minded to modifications.

Post by **jonathon** » Thu Jan 03, 2008 3:58 pm

Totally agree, should have gone to throttle bodies and a proper ECU. These would have increased both torque and bhp and reduced fuel consumption. Were they running a lambda sensor and/or cat, I'd have thought not if they had little control at idle. PPC much better magazine.

Post by **Gareth** » Thu Jan 03, 2008 4:43 pm

I noticed this article when I was browsing the periodicals in the library petrol station.

I thought that it seemed an interesting, if not a good, idea and was intrigued to see how they'd done it. By the end of the article, I was wondering not how they'd done it, but why they'd bothered.

Did make me wonder how many horses Phyllis has left - that A40 had only got 29!

Each to their own, I suppose. I've noticed over the last five years or so that most of the classic car magazines have altered and their focus has shifted away from the sort of thing I'm interested in, essentially old cars that can be used every day, old cars that can't, and things that are interesting. I've stopped buying Classics and Practical Classics so the only magazine I usually buy (but it's only occasionally that I do buy a classic car mag) is Classic and Sports Car.

Post by **paulhumphries** » Fri Mar 07, 2008 9:48 am

I've been reading the Practical Classics forum this morning and it seems the injection converted A40 had broke down.
They managed to get it to "limp home" but nothing said since.
Best they wished they'd stuck with the SU

Paul Humphries