Mike's Cabrio Build

[milliemarlin]

Re: Mike's Cabrio Build

Hi Mike,
Nice to meet you at Stoneleigh. What variety of potato do you use? I’m guessing Chopin, Vivaldi, Harmony, Melody or Accord. Certainly not Romano. How far did you have drive before they were cooked?
I have to say Millie's Zetec does not have the throaty roar of the old Pinto. I guess that is the price I pay for going green.
Paul

[listerjp2]

Re: Mike's Cabrio Build

Biggest laugh i have had in a long time. LOL

Adrian

[Mike]

Re: Mike's Cabrio Build

Cameron posted earlier that he had seen lots of innovation on the MOC stand this year.........................


My journey home would have been perfect, but for the b***dy din that bawled out of the back of my exhausts as I drove home. Today, it has really bugged me, so I've been giving some thought as to what might be the cause, and the cure.

I have twin 2 1/4" rear tail pipes as they were the smallest diameter Phoenix Exhausts offer with a rolled tip which I needed to meet IVA requirements. As I gave it more thought, the more the notion struck me that they look like ' Boy racer big bore exhausts'.
So I began to wonder if may be a smaller diameter tail pipe would quieten down the loudness.

To test my theory required something with a smaller inner bore that could easily be sealed inside my current tail pipe, but then removed just as easily:

So, now for the innovative test solution.................

IMG_6224.JPG

Two potatoes peeled to the right diameter and cored out!!!!


........and it proved the idea perfectly - it reduced the loudness noticably!!!!!!

So now for a proper solution..............watch this space!

[copperleaves11]

Re: Mike's Cabrio Build

Hi Mike . Once you start driving it regularly the development process really starts, good to hear your issues were faily minor. Regards David

[Mike]

Re: Mike's Cabrio Build

Hi David

Yes, I had a lovely, uneventful, drive home thank you. It was my first experience of the sun going down as I drove home in an open top cabin, and it was a really pleasant surprise. It was really surprising how much more vista you have in an open top car compared to the modern high waisted, low roof lined, dark interior cars we drive now days.

I think my 'problem' was/is either a broken electrical wire, or a poor connection to the throttle possition sensor. I wiggled it around at Stoneleigh which sorted the problem out while idling, and did not experience the issue again.My question now, is do I leave it alone or remove the offending piece of wire/connector and splice a new replacement section/connector?

I just have to quieten my exhaust down and it will be a pleasure to drive!

.......and stop a few of the annoying little rattles...... and.......and......and.....lots more ideas of what I want to do with it!

PS
Your E36/M50 engine management system was very impressive............and brave!

[copperleaves11]

Re: Mike's Cabrio Build

Hi Mike, glad you made it to Stoneleigh. Did you make the return journey ok, as you were anticipating possible problems. Regards David

[Mike]

Re: Mike's Cabrio Build

After saying "Next year, next year" to everyone's question about when would I bring my Cabrio to Stoneleigh? : here is one for the album








Parked out of the way, in the far corner of the MOC stand, yours truly with his "deaf aid beige" Cabrio at Stoneleigh 2014!

The next question I'm now being asked is "What colour are you going to paint it?!"

After seeing so many beautifully turned out Cabrios today I honestly don't know..........?

[dcunn]

Re: Mike's Cabrio Build

At least one camera will being waiting to record this historic moment....can't promise a drum roll and fanfare but...........

Lol

Rgds DC

[Mike]

Re: Mike's Cabrio Build

I did not intend to.............
.......but I've had a really good evening (well OK, late night!) and my Cabrio is back up and running on its new full fat unadulterated Inlet manifold.
Unusually for a Bank Holiday weekend the A1 coming home was quiet, so I had an early finish, and so I thought I would seal the petrol tank/sender with Blue hermetite before our evening meal. Its not an easy job trying to keep hold of the C-ring inside the tank whilst removing the sender so that I could squeeze sealant around the perimeter. But it went better than I thought and the job was done before dinner.

AAs I was on a roll I went back into the garage "just to have a look" at what was required to fit my Inlet manifold, and after "just starting the job" I did a bit more and a bit more, and by midnight I had her ready to fire up.

Whoooh!

Seems to idle OK but I will need to take her out for a run tomorrow just to make sure all is OK.


So, just perhaps, Stoneleigh 2014 could be in my Cabrio..........?

[copperleaves11]

Re: Mike's Cabrio Build

Hi Mike, Thanks Alan. The initial motivation for changing from the Motronic 1.3 engine management to the later 3.1, used on M50 non vanos engines was to get away from the barn door type of afm. I stumbled onto a forum where some enterprising guys had done this very conversion with some success and was fortunate to find on ebay someone selling most of the components required,( loom, individual coil packs, one or two sensors, e36 throttle body and mafs) which I managed to aquire cheaply (another pre-requisite for any conversion I attempt). It's not been without it's ups and downs and has taken about five months but I've finally got to the stage where I can say that the effort was worth the struggle. Regards David

[dogoncrazy]

Re: Mike's Cabrio Build

Hi Mike
I also installed an adjustable regulator on David's recommendation. Smoother tickover and much improved pickup just two of the benefits.
David's car now has metering and ignition /electronics from E36 grafted on/in to m20 engine via piggy back ecu. You have to see this its a work of art!!!!
Regards Alan

[Mike]

Re: Mike's Cabrio Build

Hi Mike. Have you considered fitting an adjustable fuel pressure regulator. I've had one for some time and have been surprised by the amount of control over the fuel metering that's available. In my case it's almost like having the "idle control screw" on a carburettor. Currently running 2.5 bar instead of the standard 3 bar (BMW M20). Regards David.

Hi David

No, I was not aware that such a thing was possible, or desirable?
What prompted you to consider one? Sounds intriguing.........?????

Tell me more...............

Mike

[copperleaves11]

Re: Mike's Cabrio Build

Hi Mike. Have you considered fitting an adjustable fuel pressure regulator. I've had one for some time and have been surprised by the amount of control over the fuel metering that's available. In my case it's almost like having the "idle control screw" on a carburettor. Currently running 2.5 bar instead of the standard 3 bar (BMW M20). Regards David.

[Mike]

Re: Mike's Cabrio Build

Whilst I have the Inlet manifold off........yes it is still off - long story to be told later - I have addressed another little niggle.
Ever since I connected my fuel system up I've had an odd noise rather like bubbles of air rattling along a pressurised pipe
Although I did establish it was not my pump, nor fuel supply lines to the engine bay I never have determined the exact cause.
This evening I tested the fuel lines upto but excluding the fuel rail - no noise. Ah ha! So it is likely the problem was a faulty fuel rail pressure regulator. I have changed it for a spare I had, and have high hopes of both solving my strange noise, and hopefully improve the engine's performance - fuel injectors need to be pressure fed to work properly, so mine may have been suffering? Combined with my "new" full length Inlet manifold runners, I'm hopeful my engine will feel much stronger.

[Mike]

Re: Mike's Cabrio Build

Never believe what you are told..................nor make assumptions!

When I bought my Cabrio kit, Marlin had only built one demonstrator using the BMW M50 engine, and sold one kit to a builder. In order to fit the engine width in the engine bay they had both cut 3" out of the width of the entire inlet manifold, requiring 6 individual inlet tubes to be cut, sleeved and joined. So, although I was nervous about doing it, I accepted the perceived wisdom of the time, and did the same.

Inlet manifold Cut and Sleeved

IMG_1847.JPG

Although I felt I had made a good job, I always had a niggling doubt that this could prove to be its Achilles Heal - making the engine unreliable sometime down the road.

Several years later Jeremy created a solution to the issue in his Sportster by fitting the intake boot back to front, trimming it down where it fits to the throttle body, and facing the boot back towards the bulkhead. Very simple, very cheap, and the two ports to the ICV and sump faced downwards - perfect.
I began to wonder if the same might be possible in a Cabrio?
Initially I assumed the Sportster engine bay was bigger than a Cabrio - I always felt it looked wider.

But, never make assumptions................!

Over time, talking to Danny Nelson, and seeing other Sportster builders achieve the same solution I began to ask about Cabrio/Sportster similarities, and asked for comparative measurements. I have come to understand the original Ford based Sportster shared the same chassis as the Sierra based Cabrio, and though it has undergone bulkhead and rear end changes to accommodate different BMW donor rear subframes, the front chassis/engine bay still shares the same original Cabrio DNA.

So, maybe this meant I could use the same solution as the Sportster builders? It was an intriguing thought, but was going to involve some serious engine surgery just to even find out, so I held the thought until after IVA.

Well, this weekend I finally took the plunge. I had been prompted by a very small water leak under my bell housing, which I had traced back to somewhere under my inlet manifold, but was impossible to get at unless, and until, I removed the inlet manifold.

Another factor was that I was not happy with the cobbled up Smiths sender I had been obliged to fit to make my standard Smiths Water Temperature guage work, as it was too short and didn't extend deep enough into the waterway.

So, with three jobs to do, off came the inlet manifold!



Once removed the culprit for the water leak was soon located (the rear head water port)



At the back of the head is the port which feeds the internal heater, and the rubber pipe had not sealed properly despite the jubilee clip being tight.
This was easily resolved by fitting a smaller diameter piece of rubber hose.

Whilst the manifold was removed I changed the water temperature sender back to to the original BMW VDO sender: this will have to be connected to a new Smiths Classic VDO based guage.



It's the sender on the right of the two - the blue one on the left is the engine management temperature sender which feeds into the ECU.
I had to buy a new Smiths VDO guage to match the BMW VDO sender, so there is a knock on to all this which means the dash will have to come out again to replace the water temperature guage: oh the joys of kit car building!!

Once these two minor jobs were done, the moment of truth had arrived - could I fit a full width inlet manifold and keep it all within the width of my engine bay?





............and the answer is, Yes........... JUST!

By fitting the inlet elbow back to front, and trimming it down to the bare minimum where it fits the throttle body, it just fits. This is exactly how it had worked out in the Sportsters - very very cosy, but just possible.

I am delighted, as this means I can now run my engine normally with a standard inlet manifold.
One of the things I am hoping for is that the torque curve will be shifted back down the rev range a little with the longer inlet runners: only time will tell?

(I do have two other changes in mind which will have an impact on the torque curve of my Cabrio, but they will be have to wait).

I didn't get a chance to put all my pipe connections back on this evening so have not had the chance to run my engine yet - I'm looking forward to that almost as much as the first start, as this will hopefully be the final engine configuration for this year, and will give me a lot more peace of mind.