[SMEDEN(=the blacksmith)]

Interesting story and great pictures. Just before Covid, my wife and I were planning a trip to New Zealand, the idea was a month in a rented campervan, - luckily we hadn't booked and paid anything when the world suddenly shut down. Now age and health are weighing on both of us, so that trip will unfortunately never come to fruition.
It must have been fun to see these TR6 guys in the head when they found out that you were also driving a 6 cylinder car.
PS: How does the Subaru transmission behave when it now "runs the opposite way around", I'm mostly thinking of the sound from the crown and pinion?

 

[Rednaxs60]

This is great news. My 1500, two up and towing a trailer through the Rockies got 48ish IMPG (with carbs). Glad the conversion is being a very pleasant surprise. Bit of a "sleeper" for those other speed jockeys. Look forward to the next instalment.

 

[AZgl1800]

wonderful landscape you have to drive through there.

but, but.... what's with all those cars having the Steering Wheel on the Wrong Side???

I am surprised at the high MPG you are getting with a solid car frontal area.

 

[yoeddynz]

PS: How does the Subaru transmission behave when it now "runs the opposite way around", I'm mostly thinking of the sound from the crown and pinion?

Its been fine. No noise other than the barely audible off throttle whine you'd expect from most old transaxles. The noisiest aspect of driving this car is the wind noise around the front gutters and 1/4 light windows. Nothing we can do about that. Old classic car life.

I am surprised at the high MPG you are getting with a solid car frontal area.

Yeah I'm amazed. I was no expecting this. The car weighs in at over 300kg more than a standard gl1500 too. I think the full engine management with sequential injection really makes for an efficient setup. Its geared similar to the bikes - 60mph is around 2700 rpm.

 

[OnaWingAndaPrayer]

Thanks for the report . Looks like beautiful country to ride about. Happy to hear you had no problems running with the TR6s. Sounds like a really enjoyable few days with the Imp.

 

[yoeddynz]

Thanks man. Yeah it was a really nice few days away and I'm so happy with how the imp performed. Good enough fuel economy means that we can plan some more fun road trips away.

 

[Bike...and Dennis]

Yoeddynz, can you please edit that post so it makes sense?
I'd guess "half" and "ruin" are supposed to be "happy" and "run". Right?

 

[Bryanlj]

What numbnuts invented autocorrect?

 

[yoeddynz]

I've fixed it. Makes more sense now I had used my phone and yeah - silly me. I'd not checked what auto correct has decided to put instead..

 

[yoeddynz]

Christ, would you look at the time.





Its about time I build another exhaust box. Here comes version 3.0


First I brought version 1.3 in from the garage. This box took me ages to make. Quite involved. By the time I'd got to 1.3 it was pretty good for sound but too fumy with the centre exit exhaust and not flat sixy enough. I took the lid off and looked inside.





Then this happened.





No going back now. I welded in some stainless to cover the hole created when removing the centre exits. It was now a simple box again and ready for filling. These arrived in the post all the way from China. I'm constantly impressed with the quality of these. I got eight of them landed for not much more than the price of one at 'trade' from my stainless supplier.





Before playing with elbows I machined up some more flanges for the new tailpipes. These were later welded onto the outlet stubs at each end.





I welded two pairs of elbows together, cut the outside of the curves off and then fired up the yellowhammer workshop Ryobi precision material removal machine centre..





I was so impressed with the quality of finish this machine creates even after checking on the surface table..





Wow. Amazing. I'd made sure to check all other possible measurements..





Then welded it the halves together. I was very happy with how the welding was going..





But got a bit slack and a hole appeared. Whoops. You can spot my exceptional filling job here..





So this X pipe was connected up to some leftover spiral punch silencer tube and some of the perforated tube I made, pinched from box 1.3. Its a very simple layout ..





The glass fibre silencer packing pulled from box 1.3 was still in excellent condition...





A game of 'Itchy Jigsaw' was played with the pieces until the box was full.





Sealed and bolted down the lid..





I deliberated for a fairly short amount of time on what form the tail pipes would take. Ended up with an elbow on each end and gave the pipe surfaces an 'easy care' wire brushed finish.





Before the big exciting start up this morning a nice coffee was had. Then we took some vids..

Much better!!! In fact I'm really happy with this one. Its got a lovely flat six burble at idle, which could be improved if I lower the idle rpm - currently sits at about 800-825. Its smooth and quite subtle. Could be louder with a bit less packing crammed in.


At cruise its nice and burbly, although again, it could be louder, although I've only heard it from inside at cruise. There is absolutely no droning at any point

Once its opened up its lovely. Has a nice wail. Its so fun to drive fast with the revs up. Very smooth.


Only issue is the fumes. Exhaust gases from rear facing exits are still getting sucked into the low pressure zone behind the car and drawn into the cabin when our windows are down. So my next modification (Version 3.1) will be new exits angled off at 45 degrees - sort of like this..





I still love the look of the twin centre exit exhaust on version 1.3 but I think the exits separated like it is now helps accentuate the flat six sound. The actual box design and general look could be improved further, possibly with a neat perforated heat shield ?


But yeah. Very happy with this setup. It might be a keeper.

 

[AZgl1800]

do not make it louder, it is just right as it is.
love it

and how come you keep driving on the Wrong Side of the Road ??

 

[yoeddynz]

Actually the correct side of the road. The original side the world started on

 

[yoeddynz]

Very small update. So whilst I have been making exhausts to create certain noises I have also been chasing other noises I don't want.

First off though is a pic of exhaust version 3.0 with added 0.1 extensions...



Pointing out at roughly 45 degrees and extended further these have so far seemed to have really improved the fumage issue. I'll have to do more driving with the window down to confirm. I still want to spend some time doing more tuning as well, smooth out the map and get rid of the really rich spikes sometimes seen.

So the other noises I mentioned?

Well for roughly the last couple of months I have noticed that after startup whilst in warming up and the idle is high there's a funny whirring sound coming from somewhere in the engine. It was hard to tell where when the car was sat on the ground. I'd look underneath and try my best to pinpoint it but it's tricky with all of the general mechanical sounds bouncing off the ground. I was thinking the only thing it might be was the chain drives for the oil pump having bedded creating a bit of slack on the free side and somehow whirring.

The release bearing was also occasionally making a tinkling sound, or possibly its actually the 3 bearings I had fitted in my 'thrust bearing 2000' assembly that resides between the back plate and the flywheel.

Oh and the new exhaust has a tiny rattle on one side. Only noticeable if I smack the box up on that side (a quick lesson was learned not to do this when its searing hot) and I suspect its actually the tube the runs through the flexi joint just touching. Hopefully I can rectify it by adjusting the bobbin height on that side.

But this whirring sound? It goes away somewhat when the idle drops as the engine warms up and I cant hear over the exhaust from then on. So this morning I started the car up, moved it from its garage and out into the sunshine. I let it warm up. Then moved it inside and onto the hoist. Once up in the air I started the car (using my go go gadget arms) and listened from underneath. Being fairly warm the sound was barely audible until I reached up with my arm to the throttle body and gave the engine a rev. Bingo- there it is! Its in the cambelt cover! Its a flappy whirr. A rubbing flappy whirr.

I let the engine cool down, went for a pushbike ride and then this evening it was off with the cover, which luckily is super easy to remove once the alternator pulley is removed from the crank.



Zoom in..



That bottom belt run on the left was a bit loose. Not terribly but certainly a bit more than the specified 5-7mm Honda advise. When the engine is cold its free to move that amount. I presume as it warms up it gets a touch tighter (boxxer engines 'grow' a little in width as they warm) The manual states that if the belts are too loose they can flap against the cover. Too tight and they whine. I could see where its been rubbing on the cover..





I have now tightened both belts just a smidge. Its a bit tricky to exactly measure 5-7mm but they seem about right. Cover back on and I'll test it tomorrow. (I'm not keen on filling the workshop up with warm up fumes tonight when our bedroom door is about in line with the roof of the Imp)

Interested to know if this is an issue many Goldwing owners have had?

Also to note. This morning was an especially cold 'late summer' start to the day of only 2 degrees.

After I started the car later in the morning and moved it out (around 12 degrees then) I opened the engine bay lid for a look while it was warming up. I soon spotted one of the injector rail hose clips at the front was leaking. I promptly tightened it up and leak be gone.

I can only presume the rubber hoses had shrunk ever so slightly in the cold night and allowed the fuel at 40 psi to weep past. I checked all the other fuel line hose clips in the engine bay and one other was slightly loose. I must check the ones in the frunk too!

 

[julimike54]

Presume you know this but...

Honda on the 4 cylinder models specifies the belt tension as so much pressure in force, at a point in distance from the pulleys will yield 'x' amount of distance deflection.

Not familiar with the six cylinder version but surely they have kept a similar measuring spec.?

As you stated the boxers tend to grow or shrink slightly with temperature, so if it was warmer when you set the tension it might have gotten a little looser with the colder temperature.

Best of luck...

 

[yoeddynz]

Thanks Mike. I'll certainly report back with my findings 😊

 

[Rednaxs60]

You are having too much fun! Keep the rubber side down.

 

[yoeddynz]

Thanks Ernest. Yeah it's fun. Luckily just a toy and so fun but now that it's turned out to be really cheap to run as well we can plan little road trips with it.

I'd be keen to know what your ignition table looks like. I think mine is quite conservative and I reckon could do with a bit of advance up high.

Also - I see you've popped up on oldschool. There's a lot of bike stuff on there. I bet they'd be interested in your bike!

 

[Rednaxs60]

Have been browsing the old school forum. Interesting forum.

As an aside have another project underway. Replacement for the 1200 GW ignition control module using a Speeduino interface board with an Arduino 2560 for ignition only. Collaborating with a fellow in Austin Texas, I have most of the replacement components, he has the bike. Good mix.

I have just reverted back to wasted spark and paired fuel injection, and finished other minor wiring changes. Reason is that not a lot of benefit from sequential besides emission standard at idle and low powers, and most importantly, I want my dash RPM reading back. It will be back on the road for tuning and trials later this week, early next week. The ignition table is from PSIG on the Speeduino forum. Honda was very conservative with the ignition table specifically it left room for a lot of calibration. It was mentioned on the Speeduino forum that the Honda ignition table was very conservative. Will be using Tune Analyze Live again. Works pretty good and takes a lot of the guess work out of the initial tuning phase.

Have wired a couple of GM HEI 4-pin coil drivers to use in place of the OEM spark units. Doing this because there are no known alternatives for the 1200 FI models. Once I get the engine operating again, will swap out the spark units and give a try. Alternative components have been identified for most other CFI system components.

Attached picture of the ignition table. The Honda 1200 FI models have an ignition timing range from "0" to 45 degrees:

 

[yoeddynz]

Great- I'll have a look over that table and see how it compares to mine.

I have emailed a couple of businesses that claim to re-map GL1800 ecus and asked what their tables look like, or even just what do the stock Honda maps look like. But no replies yet. I'd love to see how far advanced Honda run their tables at higher revs.

This is what my table looks like currently...

 

[Rednaxs60]

Good looking table. I have access to the 1200 FI models ECU code. Have no way of changing the program but I'm able to isolate the fuel tables for SD and Alpha-N. Only issue is translating the figure to decimal. I think there are ignition timing tables as well. This is the Github site for the 1200 ECU coding: ECU-Reverse-Engineering/GL1200 at main · RhinomanUK/ECU-Reverse-Engineering