How to Fuel Inject a Classic Mini - First Start and Overview

[@JB-ll5br]

Nice overview of what's needed to inject a Mini with a throttle body. I'd like to emphasize something you covered which is the need to have a throttle body with 2 injectors and the need to have them firing every 180 degrees of engine rotation, alternating between the 2 injectors. This allows you to have injectors small enough to be able to tune the idle and low load region as well as provide enough fuel at high load/high RPM when the 2 injectors fire together (pulse widths of more than 180 degrees). Trying to use a single injector for a turbo setup would make for a very hard to tune setup, especially if fired every 180 degrees. So no matter which throttle body you use or which ECU you use, you will want to have a setup with 2 injectors close together and you will need to have an ECU that allows you to do the 180 degrees alternating injection setup. Anything else will be impossible to tune to get an adequate fuel distribution between all the cylinders. A port fuel injection with separate ports and injectors is possible and can provide an even better result but the complexity and learning curve is in a different league. A second point I'd like to make is your assertion that you don't need an intake temperature sensor. I have no idea how you could do this unless you use a MAF (which is not your case). The intake temperature is essential to let the ECU know how much fuel to inject and this is even more essential with a turbo setup where the temperature can vary wildly. It's simple physics where you use the intake pressure and temperature (and RPM) to compute the air mass and then compute how much fuel is needed to get the desired air-fuel ratio. Without the temperature, the ECU can't compute how much air there is so can't compute the actual fuel needed. Just as a note, I'm the guy who added features to the Megasquirt 2 code to cover the needs of port injecting the Mini siamese-port engine. So I am familiar with the issues with injecting a 5-port Mini engine either through port injection or throttle body injection.

[@classicminidiy]

Thank you so much for taking the time to write this, as this information was incredibly helpful. It is going to lead me to tweak some of the settings in my ECU and hopefully get this running in a much happier way. I am going to share this entire writeup in full with my tuner so he has it when we get the car on the dyno in October.

[@KevinBuckham1]

Regarding the lack of an intake air temperature sensor, at idle speeds coolant temp can work very well for controlling fueling. This is probably due to fuel pooling and vaporization more tied to manifold wall temperature which tends to match coolant temp at low airflow. One possibly might get away with coolant temp sensor to control idle fueling and run somewhat open loop at higher RPM. (Not that I'd do this, just pointing out it's possible.) I personally use and would recommend an AIT as well, but merely mentioning it's possible in one region of operation.

[@rennkafer13]

JB, any reason not to use the MPI manifold/throttle body/appropriately sized injectors? Already has an idle stabilizer.

[@JB-ll5br]

@@rennkafer13 Port injection is much more involved and the MPI setup is not adequately sized for a turbo setup but could be used for a middle of the road naturally aspirated setup. In a port injection setup, you need to have an ECU that will allow you to tune the injection timing as a function of load and RPM. And you need to monitor the exhaust (oxygen sensor) independently per cylinder to assess if your injection timing and your injection pulse widths are correct for the entire load and RPM range. There's a lot more to it than this short overview. There's also a lot more about the theory and issues of port injecting a Mini and many different setup examples on the TurboMinis forum.

[@chelee6302]

Hi, JB from my understand, the siamese code for port injection is all about the injection timing vs rpm which is way more important than the wet wall setup, my question is, if I change the cam to a hotter one, I assume the timing will need to be adjusted to match the in/out duration, is this correct?

[@TheGentlemensMotorRacingTeam]

this is amazing info for anyone wanting to fuel inject their classic mini - thank you

[@MikeAarset]

Going to watch this vid a second time. Really great info. I think a lot more peeps would be interested in what you are doing if this Throttle Body you had created fits in other A-Series cars like Morris Minors or mg midges or Sprites. I know it would bolt in but hood clearance might be an issue. I own a 1960 bugeye sprite and wanted to do a EFI and a electronic ignition for a while now. That A - series engine sounded so nice when it started up. As much as I like SU carbs I think it would be so nice to not have to fiddle with them as the seasons change. Keep up the great work.

[@classicminidiy]

Thank you I really appreciate the kind words. I actually think it likely wouldn't have a clearance issue as this is shorter than the original HIF44 even with the fuel rail. Would def love to see someone give it a go and if you wanted to try it out and it didn't fit I would totally be fine accepting a return (just saying) :-) Thanks for watching!

[@stuartbradley1142]

Who supplied your intercooler set up or was it something you put together… Very interested in one for my turbo build!

[@classicminidiy]

It was made by The Car Kitchen as a kit to pair with the turbo setup.

[@MiniMattTV]

Yes!

[@classicminidiy]

Yes!!!!

[@danl458]

Hi, do you have info on the vw coil you used? I can't find any info saying it has internal ignitor? How can you tell it does? Thanks

[@classicminidiy]

Hey this is the coil in question. amzn.to/44Aw7Lx

[@scottmartel9184]

Will this set up suit a 998 Moke

[@gimmefuelgarage8339]

Some great info in here! something i had considered doing with my 850 was fuel injection. this gives a great break down of how i would do this. I wonder what kind of gains i would get. in both driveability, reliability and power

[@classicminidiy]

Thank you! I havent seen an 850 injected before but I think it could be an interesting project. I don't imagine you would see a ton of difference in power but driveability could be improved. Although the 850's are already really reliable runners when it comes to these engines.

[@gimmefuelgarage8339]

@@classicminidiy Its really food for thought, i want to make my 850 a cool modified little engine. I also have a few 1275 engines carb and mpi to play with... So all your info is very useful :D thank you. one i will most definetly refer back to when building :D

[@austingato]

I made my 850 fuel injected..55hp at the wheels.

[@gimmefuelgarage8339]

@@austingato that’s great any other supporting mods?

[@KevinBuckham1]

Very, very impressive! I'm curious why your idle was so rich? Was it still in a warm up routine, or perhaps the funky port configuration requires the extra fuel to idle nicely?

[@KevinBuckham1]

I looked again and it looks like the coolant temp is still low (109F). Super slick! If I wasn't D16 swapping mine, I'd be buying this.

[@classicminidiy]

Thank you! No reason other than I haven’t got it all dialed in yet. Leaned on rich side to get things working and then leaning it out and refining over time.

[@luizf.1692]

Please, answer my question as 2nd time. My Mini is Spi. Can I use the same ECU, sensors, etc??? Need to adjust the fuel mixture every time that I go to Technical Control here in Spain below 0.5%Co with your fuel injection body. Know that few things nerd to be done. Please, clarify. Also, you should get a normal Mini with carburator and to show how to install your fuel injection. Your MINI is not what the majority of us have. My 2nd Mini, 1978 1100CcI has twin carb and does not pass the T. Control with higher than 3.5%Co. Looking to install your fuel injection, ECU, sensors, etc in order to comply with the law. Thanks.

[@classicminidiy]

Hey Luiz I didn't see this question the first time you asked. However, the original SPI or MPI ECUs do not work with our manifold. Those ECUs require a very specific configuration with their sensors and hardware. In order to swap to the newer modern EFI throttle body, you would also need to use a different ECU(Speeduino, Haltech, Megasquirt, etc.). The new ECU can use many of the original sensors as long as you set the scaling details in the ECU map to match them. I may try to find another car to swap to EFI in the future however the changes made to my car are the same as it was carburetted and moved to EFI. So the sensors, and hardware I talk about in this episode would be the same required on any car.

[@generalsquirrel9548]

Funfact the later models (1991 or 1993 onwards) actually came with injectors dual to emmision standards appearing

[@Dagowly83]

Late 91-96 was Single Point Injection (SPi), 96-00 was Multi Point Injection (MPi). Although MPi is technically TPi, and the system is incredibly clever to inject for each port in a specific/custom timing.

[@user-du8cs8sn2v]

So.... Looks like you've figured out why you couldn't get the Holley EFI working - Siamese port head! :)

[@Dagowly83]

Siamese port/charge robbing is almost irrelevant to the Holley set up as the air and fuel are mixed prior to being boosted and create a wet manifold set up. There were many other issues with the Holley that caused it to be unsuitable.

[@ToddDunning]

Hmm, marriage or EFI?

[@classicminidiy]

You can only have one.

[@tokecolding7568]

Easy. If you have found the right person for you, you will know that this person feels the same about you, when you choose marriage and that person choose EFI.

[@franciscomelendez3894]

Add a flip front-end

[@classicminidiy]

Haha no I dont think I want to chop up the shell of a 1960 mini for that. Though it would make access ALOT easier!

[@Thecarislife]

oh no, i did it wrong!

[@classicminidiy]

Dangit! Time to redo everything!