95 replies to this topic

[miniBrain]

 

 

Charge robbing is a huge issue with the SPI system, some say It's worse than a single SU set-up. Siamese port injection would solve this, but not worth the headache IMO. A 7/8 port head is the only solution. It would be easier to turbo with the SPI system though, very accurate and, relatively, easy to tune. Interesting build. Post some clips of it running.

 

Here's a clip -

 

 

Nothing exciting to see in the video, except now I can mash the pedal to the floor at any time and the engine just keeps accelerating without complaint. There's probably no gain in power but driveability is much much better.

 

 

 

I'm still super impressed that all this is built from nothing.... very good esp having to write the software etc.

 

 

 

Thanks, mate - I've had a bit of practise though, about 30 years! I'll get the hang of it soon!  

[monkey]

Looks awesome! I have been toying with the idea of trying to do something like this looks amazing!

[chuffed]

This seems like such a good idea, and i'd imagine it'd be pretty popular if you did it in a kit form! I'd certainly be interested!

Sorry if this sounds stupid, but how would it work on different sized engines (mainly 998's!) And how would you be able to tune it up with the system? Eg you wanted a facier set of cams/nice head?

Thanks

[spiguy]

This is superb. I fully agree with many of the posters here that the SPi setup is superb. Shouldn't realy be any worse issues of charge robbing, since the SPi is a wet manifold system and essentially just an electronic carburettor... As was said the turn the key and go performance is really nice, and you don't lose any sense of it being 'a mini'. Well done to you, and I am very interested in this especially as it is arduino based! I use arduinos at work in various custom pieces of test equipment. What are your plans for it in the wider sense? Do you plan to sell it or make it available as open source?

 

Have you had it RR'd to prove that there are no 'gaps' in the maps etc and it doesn't do anything untoward through the rev / load range?

 

Again, top work - really nice to see somebody investing in the injection setup as you usually see people who say the SPi is rubbish or too complicated, and converting back to carbs!

Edited by spiguy, 12 September 2015 - 07:19 PM.

[miniBrain]

Top work! I really like this, having a SPI myself I can even see the benefits of replacing the stock ECU for tuneability.

 

You should get some improvements as I understand that cars from the factory are de-tuned slightly to cater for low-grade fuels, etc.

 

Looks awesome! I have been toying with the idea of trying to do something like this looks amazing!

 

Go for it, I can guarantee you'll have a load of fun in the process!

 

 

This seems like such a good idea, and i'd imagine it'd be pretty popular if you did it in a kit form! I'd certainly be interested!

Sorry if this sounds stupid, but how would it work on different sized engines (mainly 998's!) And how would you be able to tune it up with the system? Eg you wanted a facier set of cams/nice head?

Thanks

 

For a different engine you'd need calculate the Required Fuel parameter then start with a best-guess VE map. If you wanted precise tuning, then you'd hire a rolling road session. Alternatively, you can drive it on the open road and try to gather Lambda data for all cells in the VE map, then adjust the VE Map accordingly - lean for economy, slightly rich for performance. It won't matter what cam/head/etc your're using 'cause you'll be developing a VE map for the specific engine.

 

Not thought about kitting it out yet but if it works reliably for the next 6 months throughout the winter, then I might give it a go.

[miniBrain]

This is superb. I fully agree with many of the posters here that the SPi setup is superb. Shouldn't realy be any worse issues of charge robbing, since the SPi is a wet manifold system and essentially just an electronic carburettor... As was said the turn the key and go performance is really nice, and you don't lose any sense of it being 'a mini'. Well done to you, and I am very interested in this especially as it is arduino based! I use arduinos at work in various custom pieces of test equipment. What are your plans for it in the wider sense? Do you plan to sell it or make it available as open source?

 

Have you had it RR'd to prove that there are no 'gaps' in the maps etc and it doesn't do anything untoward through the rev / load range?

 

Again, top work - really nice to see somebody investing in the injection setup as you usually see people who say the SPi is rubbish or too complicated, and converting back to carbs!

 

I'm running it with a Uno at the moment but its maxed out on memory, so for the "MkII" version, I'll move to the 2560. This will let me do more exotic things like auto-tune and multiport. When I get the 2560 version running and have some confidence in the design, I'll get some PCB's made and build a couple of "proper" units. I'd need to prove the reliability of the Arduino over a longer period before I can even think about making it available. That's what I'll be focussing on in the next 6 months or so. Having said that, I've had an Arduino in my TR7 for over a year (to control the fan and an electric water pump) and its never missed a beat.

 

I know there's gaps (i.e. areas that I can't reach in normal driving - e.g. high RPM + low load, low RPM + high load) at the moment - so I've just interpolated (aka guessed!) the VE values from the surrounding data. But to be honest if the engine doesn't go there in normal driving, then I'm not too worried about the accuracy of the VE in these areas. I haven't had it RR'd yet, but might do in the future.

 

Yeah I've read a lot about people converting to carbs but for me it's a backward step for daily driver. Just hate the thought of going back to a choke!

Edited by miniBrain, 12 September 2015 - 08:09 PM.

[monkey]

Have you thought about mappable ignition as well?

I don't know if I quite have the knowledge yet to attempt this, but i would certainly consider trying sometime in the future!

[miniBrain]

Have you thought about mappable ignition as well?

I don't know if I quite have the knowledge yet to attempt this, but i would certainly consider trying sometime in the future!

 

Hi,

 

Once I get the fuel side fully worked-out (e.g. with multiport and auto-tune) then I'll see how much CPU time I've got left. Might be a stretch for CPU I'm using at the moment. 

Edited by miniBrain, 12 September 2015 - 08:18 PM.

[Spider]

Just wanted to say that while I don't have much (nothing!) to add to this thread, you are one clever dude, cheers mate, good stuff

[miniBrain]

Just wanted to say that while I don't have much (nothing!) to add to this thread, you are one clever dude, cheers mate, good stuff

 

Thanks, mate, very kind of you to say 

[l_jonez]

Nice work! A wideband sensor would really improve things.

[miniBrain]

Nice work! A wideband sensor would really improve things.

 

Totally agree - it's on my (growing quickly) to-do list 

[screech]

 
Totally agree - it's on my (growing quickly) to-do list 

This has made a very interesting read. Well done and good job.
How's it going at the moment?

It's actually pretty much what I've got planned to do to mine over the winter, I've got most of the bits. I'm just not clever enough to build an ecu so im currently looking at my options.
I will have a few questions which I'm hoping you'll be able to answer.
My first job will be to strip down and clean the spi unit, looking around it, there are a few outlets or inlets that I'm not sure about and also what sensor is what!

[miniBrain]

Thanks screech!

 

I'm using the Mini daily and I'm just loving the SPi set up - never going back to carbs if I can help it. I'm working on ECU version 2 - PCBs for it arrived today and I'm building one at the moment. This should give me multiport injection and programmed ignition - but its not going in the Mini though.

 

Be happy to answer any questions - if I can!

[Ethel]

I don't think you'd have to develop a wideband, unless you wanted to. All the available ones I know of have an analogue AFR output (0-5v), or  some sort of serial interface for data logging.

 

One Arduino project I'd do if I had the skill and time would be to emulate an OBD data stream through bluetooth, so I could take advantage of existing smart phone apps like Torque Pro.