NA AA2 - 50°C difference in exhaust temperatures

[Ben]

Hi all,

I've bought a rough naturally aspirated Ariel 2 last year and totally neglected the car until now as life had other plans for me.
So currently I am trying to resolve the non functioning tachometer as well as some other problems with the car.

Is it normal that the export headers have way different temperatures? Was just having the car Idle for a couple of minutes and cylinder 2 and 3 where 330-340°C while 1 and 4 where at 270-280°C.
Sure, 1 and 4 or on the outside and have more mass to heat up while 2 and 3 get heat from everywhere and should be hotter while warming up but a 50°C difference seems a bit too much.

The measuring was done with a el cheapo Infrared thermometer but consistent.
Am I making up problems and should not interpret too much into it as the engine wasn't at operating temperature?

Thank you,
Ben

[Curves Junkie]

Hi Ben,
which engine have our Atom?

[Ben]

Hey Curves Junkie,
my Ariel uses the Honda K20A2, normally aspirated, unfortunately it uses the MBE ECU. So, from what I understand, I can't get any diagnostics data out of the system.
Ben

[Curves Junkie]

Hallo Ben,

I have an AA3SC with K20Z4 so I can't tell you too much about the AA2.
If you have a SPA Dash, it gets its speedometer signal from a wheel speed sensor located on the left drive shaft. Check to see if the magnet has been lost.

On my AA3, Ariel installed a Hondata ECU. Why you have MBU - I don't know. My AA3 has an OBD connector below the ECU.

I'll be at the trackday in Dijon next Friday. Then I'll measure the temperatures at the exhaust manifold.
I seem to remember that I had measured it once before and the temperatures were different as long as the engine wasn't kicked.

Grüssle

[Ben]

Hey Curves Junkie,

thank you for your input, my current plan of attack is to send in the injectors to be cleaned and matched. After that I should have a solid basis on where to look at.
The early AA2 seem to be equipped with the MBE Setup that was later changed to a Hondata ECU until as well. I am pretty sure that my car has some electrical gremlins hidden somewhere, probably something as trivial as a faulty mass or something like that.
I already have a spare cluster unit and will change that as soon as I have spare time on my hands. Can't really move the car right now as some idiot (me) put 100kg of batteries in front of the car in order to charge them, that will only take a week or so.

Regarding the location of the speed signal, it's exactly the same on the AA2, everything seems alright, nothing obvious. Picture below.

@Curves Junkie have fun at the Dijon-prenois circuit.

Cheers

[Curves Junkie]

I am pretty sure that my car has some electrical gremlins hidden somewhere, probably something as trivial as a faulty mass or something like that.

LOL, thats normal.
Our first ride in 2016 to the Austria mountains ends with a complete failing electric.

Can't really move the car right now as some idiot (me) put 100kg of batteries in front of the car in order to charge them, that will only take a week or so.

Maybe you bought the first electrical Atom.

Regarding the location of the speed signal, it's exactly the same on the AA2, everything seems alright, nothing obvious. Picture below.

Shows the speedo something but the wrong speed?

have fun at the Dijon-prenois circuit.

Correct. Many thanks - its a great circuit - makes a lot of fun.

[Ben]

Can't really move the car right now as some idiot (me) put 100kg of batteries in front of the car in order to charge them, that will only take a week or so.

Maybe you bought the first electrical Atom.

Hell no, the Ariel is the worlds most unpractical car as it is, it combines all of the negatives from a motorbike with all of the negatives from a car into one vehicle.
Lets take away the ability to just drive to a petrol station, where within minutes you can get dinosaur juice into the vehicle to power it for great distances.
The batteries are for the solar system on my roof.

Regarding the location of the speed signal, it's exactly the same on the AA2, everything seems alright, nothing obvious. Picture below.

Shows the speedo something but the wrong speed?

It just doesn't move at all, so now I might have an excuse to buy an oscilloscope

have fun at the Dijon-prenois circuit.

Correct. Many thanks - its a great circuit - makes a lot of fun.

Been there only once, some pretty long and fast corners. Unfortunately someone in a classic car didn't get that memo and probably didn't have a oil pan swamp or a dry sump system, that combined with new tyre technology wasn't that great for the engine that just seized up.

[Curves Junkie]

Regarding the location of the speed signal, it's exactly the same on the AA2, everything seems alright, nothing obvious. Picture below.

Shows the speedo something but the wrong speed?

It just doesn't move at all, so now I might have an excuse to buy an oscilloscope

You can check Pin 11 to 13 at SPA connector for signal.

[Gambba]

Hi Ben,

You may want to check what exact model of ECU you have and if OBD can be added to it. I have an MBE ECU on my AA2, but it was replaced and at the same time OBD added to it.

Have a check on SBD Motorsports website as there is tons of info on the MBE ECU’s.

Mines an NA K20A2 also, but I’ll be fitting a supercharger soon and keeping it on the MBE ECU and tuning it, so have done quite a bit of research into the ECU’s.

I’m getting rid of the SPA dash as whilst mine still works expect it will fail at some point based on other owners posts……and the AiM dash looks cool too!

Good luck!

[Ben]

Hey Gambba,
welcome to the forum and thank you fora ll of the information.
Quite interesting that there might be the possibility to upgrade the MBE ECU with OBD, will do some research when time allows.
I wanted to upgrade to a digital dash anyways because .. well because it looks pretty hightec and just cool. If I'd have one car without dials lets make it the car that doesn't have car things like doors or a roof.
Also for some reason the LCD display in my dash stopped working and without the total milage counter I can't pass the german TÜV/MOT.
Thanks
Ben
As I have a photo of the ECU on hand I thought I'd upload it, maybe someone can use the info somehow:

Update #1 2023-08-09 14:29 UTC
I've ordered a OBD Port as well as a CAN Mapping Kit from SBD Motorsports, really reasonably priced I might add. Thank you for the tip Gambba

[Gambba]

Great Ben!

My ECU is a 9A4B with the OBD. I’ll run those OBD wires in the main harness to get that on the AiM dash. I was planning to buy the AiM dash online, but recent trip to the Ariel factory found the dash is the same price from them and has the Ariel logo on…

Hopefully you should be able to take the map from your old one and transfer it over. I’ve not used the mapping kit myself and will have Steve (SBD Motorsport) map mine remotely once the SC is fitted.

I’m just going through my AA2 to sort a few items out and make it a little better along the way. I needed the supercharger to get the Jeremy Clarkson face (obviously it was G and not the wind that did it).

[Ben]

Quick update
The OBD mapping kit and the wiring harness arrived. Installed Easimap 6, after some minor stuff I am now presented with this.

Next task is to backup the ECU and flash the newest Version.

So the ECU not knowing the rev signal explains the Dash not showing anything. So no rev signal and no speedo, maybe the dash isn't broken it just does't get signal.
Could someone please guide how I could check the rev counter signal? How can a functioning ECU not know the rev signal?
I've had engines that would not start because of problems with the crank sensor and/or trigger wheel before.

[Ben]

Quick update #2
As it didn't make any sense that the ECU of a well running injection engine doesn't know the revs I've checked every connection, I took apart more then I care to admit.
Long story short, all is well, the OBD mapping kit is working as expected.


I also got the original SPA Dashboard to work, unfortunately I can't really tell what did the trick as I've checked every connector, plenty of contact spray was used, resoldert some connections that did not seem too convincing.
https://www.youtube.com/watch?v=w2sd6Pt1ELk
I will probably post some question here pretty soon as looking into the wiring loop raised some questions.
Also I might not have taken good enough notes on how I took stuff apart.

[Alec]

Hallo Ben,

On my AA3, Ariel installed a Hondata ECU. Why you have MBU - I don't know. My AA3 has an OBD connector below the ECU.

Grüssle

The early Atom 2 had a choice of three NA engine powers, 160bhp, 220bhp & 245bhp, with the Hondata ECU only being fitted to the 245bhp engine, which is what is in my Atom 2 that I've owned new from August 2006.

Which powered engine does your Atom have Ben?

At one time, I also owned a second Atom, which was the lowest powered 160bhp model, but that was sold on again some years ago.

Any way, I'm also attaching a screen-shot of part of the Ariel configurator, showing all the engine options.

Regards,

Alec.

[Ben]

Hey Alec,
thank you very much, so I've just learned something.
I was not aware that there was a 245 HP NA nor a 275 HP boosted option available. I actually have the COC "document" on hand, picture below.
It states the power as 161kW, that converts to 216 mechanical HP and 219 metrical HP, so what you write makes total sense as my car came with the MBE ECU.
Would you happen to know the differences between the 220 HP and 245 HP, besides the ECU? The difference of 1500 GBP price kind off tells someone that nothing too mayor changed.

Ben