Chrysler Sunbeam T6.... to turbocharge or supercharge?

[BackCountry]

Wow! Wow! Wow! Leftfield ideas, methodically thought out and beautifully executed to create street/track weapons! This is what RR is about for me; reading stuff by people who know what they're doing, doing the stuff i cant! Trully inspirational!

[turbeam]

Cheers BackCountry, I'm glad you like it.

I wasn't sure whether to give details of this project at all in a thread on what is really a car forum, but it seems that many other people can also appreciate things like this for the sheer technical challenge of it, and for me this is at least half the fun of doing it. In this respect at least many of the hurdles are the same whether it is on 2 or 4 wheels.

On this project as on any other involving a major power unit transplant, I try to first get all of the biggest, most important and least 'alterable' parts in place first, then progessively work down to the smallest, least important and most easily repositioned/ modified/ replaced/ ommitted parts. I'm very reluctant to have to stretch the frame in this case, spo although it seems a bit backward the engine needs to be offered up to the chassis first, but at a rough estimation there appears to be plenty of space left for the basic cut-down crankcases/ gearbox to sit in behind it.

Only then will I be able to look seriously at how to get the primary drive from the neartside of the engine into a gear on the clutch outer basket, which will al;most certainly involve adding a jackshaft running behind the engine abnove the gearbox.

Routing of the six bulky expansion chambers and finding somewhere to mount the cooling system radiator/s will probably come next.... but I'm getting a bit ahead of myself now. On the cooling system front, the original arrangement wouldn't even have used a pressurised system as the bike version will need.... it literally just lifted raw sea/ fresh water, pumped it around the engine and then dumped it back into the sea or lake again. The temperature differential between the hot engine components and the raw cooling water in this case will be very different from that in a normal sealed and pressurised cooling system, so I'll have to look carefully into this when making the alterations to be sure both that cooling is adequate and that the original joints and gaskets can withstand the new increased pressure.

To me it is a bit like doing a jigsaw puzzle, except that the box lid and half of the pieces are missing.... but on the plus side there are odd parts from several other different jigsaws lying around..... plus some thick card, felt tip pens and scissors. With patience and a bit of forethought, it should be possible to make something out of it all!

[turbeam]

After getting the big Mercury engine installed in the frame and hanging on its temporary steel mounting brackets (which will be used as templates for making the aluminium alloy versions later on assuming that no further alterations are needed), I thought it might be a good idea to do a rough mock-up of the build.

The first photo shows how well the new power unit sits in the bare chassis and gives a truer impression of its real size. I'll eventually make or adapt a fairing to cover it all so very little if anything of it will be seen in the complete bike, so providing it can all be well packaged the 'secret' of the power units source should be safe....






I bought some very cheap, poor condition Hayabusa parts in case they might be of any use, but I actually find the original parts quite ugly and the stock fuel tank surprisingly doesn't even fit very closely to the shape of the frame as the stock fairing and infill panels hide quite a lot of the big gaps along the sides. I won't be using these parts, or at least not in the form that they are at the moment... ugly, ugly, ugly....







The GSXR SRAD tank is a much nicer shape, and although there are some differences in the frame dimensions I though one of these tanks might be a better starting point as the frames are fairly similar in basic design. The Hayabusa has a wheelbase that is about 60" long in comparison with the SRAD's short 56" wheelbase. The 'Busa swinging arm is already 2" longer on its own, and the frame also appears to account for about another two and a quarter inches....






The underside of these tanks have huge recesses to clear the original airboxes, and I'll be cutting the stock bottom right out of them to clear the upper expansion chambers as well as making space for the new intake tracts anyway, but done in a way to also keep plenty of fuel capacity. The poorly black repainted and damaged SRAD tank here was also  bought very cheap on Ebay, its minor copsmetic damage is unimportant to me as it can be repaired while it is being cut, stretched and raised to better fit the frame at the same time. After this has been done, its propoprtions in combination with the modified RG500 seat unit should be just about right.....





From these last photos a good impression of how the engine should be positioned in the finished machine from the nearside can be seen. Without front forks fitted it looks to be very long, but in fact the front wheel position has been set at the stock 60" wheelbase to check on tyre clearance to the 'upper' cylinder head etc. The two upper expansion chambers will probably have to stay near the outside edges of the engine to give enough clearance for wheel turning on their way over the top of the engine, and I'm not yet certain how/ where any radiator/s will be mounted...... I'll cross that bridge when I come to it.....

[turbeam]

 All thoughts of winter projects had to be put aside to get EGA ready for action over the summer months.   I've been very busy so haven't really had much chance to post for a while.


Loaded up ready for the off the the CCHMSC / Saltire Rally Club stand at Glamis last week....





On the stand...

.


My two other favourite cars on the stand.   Renault Alpine.... we saw many of these at the 'Monte  Carlo Histoprique Sezanne start last year, involving cars that are very popular with French drivers on the event....





Possibly my very favourite..... Dave Spence's MK1 Capri fitted with 302 small block and T5 drivetrain from a Mustang...... which also had aftermarket heads etc and 'breathed on' motor which sounded just amazing.....




August and September are very busy months for EGA, with five major events over 7 weeks, so I should be kept busy on preparation works even without a prang or off!

[Finlay]

Wow, what an awsome machine !!! Loved the vid at the start, the arches look amazing !!!

[turbeam]

Cheers Finlay. I've been a bit sidetracked with other projects over the last few months and very little real progress has been made on EGA. I haven't had a lot of spare time for posting updates either.

On the cars last competitive outing I fitted it with a hydraulic handbrake to help it get around some of the tighter cones/ pylons on a 'test' type rally, and this had some unforseen effects on the car which resulted in a cracked/ bent panhard rod, a broken offside rear damper rodand a couple of other more minor failings. Some further strength upgrades are now underway to prevent any recurrance in future.

Here is the combined hydraulic handbrake that acts on the rear discs, the normal cable handbrake that operates the internal expanding shoes, and the variable angle Girling G-valve that reduces rear brake pressure under hard braking....



As it is now just about the end of the competitive season, I have plans to make a start on check-fitting some of the supercharger related components over the next few months, so hopefully it will be in a slightly different spec by next spring.

I also recently bought another really rough ex-rally school shell that I plan to build as a 'rough' car for use on harsher events. EGA was originally built primarily for circuit/ tarmac use, and some of the things I've been doing with it have really been a bit too harsh for it.

The 'new' shell...






EGA just after scrutineering and about to start the first test of the Doonhamer Classic Rally...





Some of the in-car footage showing why the rough car is needed. Apart from the obvious mechanical failures in Part 2, too many driving and navigation errors are still costing far too much time, but it continues to get quicker and quicker, especially on tarmac....

[claymore]

Looks like you could benefit from a quicker steering rack.

[niterida]

Bike project is awesome - gotta love 2 strokes - I once built an RG500 powered NSR250

Have you thought about the effect of having a spinning crankshaft sitting so high in the frame will have to handling - I think it will make it a bit harder than normal to steer ??
Would it not be better to mount it normal way up but tilt right back so the exhaust is coming out right underneath the seat ? Then mount a nice airbox down low feeding directly into the reeds ?

[turbeam]

A quicker rack would be helpful Claymore, and I actually have a 2.9 turn rack waiting to go in, but when running with a lot of rubber on the front end in normal tarmac/ circuit use I'm sure I'd also then need a power steering column as well..... and I just don't have time to be playing around with that right now. Plus, I do like the feedback that I get now without any assistance and it is more the rate of turning the wheel that is an issue rather than the steering weight.

Niterida, I'm not really sure what effect having the crankshaft sitting so high would/ will have. Probably some additional flywheel effect yes, but there won't be anything else driven from its ends other than the gears for the contra-rotating jackshaft that drives into the clutch basket on one side and the trigger wheel on the other.

I mulled over the options for quite a while, and came to the conclusion that its most compact arrangement is with the reed blocks in this position and throttle bodies sitting beyween the frame rails as mounting the other way up would take up more space needed for the gearbox. With fuel injection replacing the original carburettors though, it would have been possible to have the reed valves on the lower front too, but there would still have been six of them and a fair bit of space would be needed.

This bike isn't going to be raced or anything like that anyway, its only really being built for the hell of it and the fact that I like two strokes, that they are becoming ever less common for anything above about 100cc, and that a 2-litre V6 with 'only' 150 bhp but a huge amount of torque in a fairly modern 'normal' bike chassis arouses my interest....especially if I can hide most of it except the expansion chambers under a fairing.

Although the short wheelbase wouldn't make it ideal for the purpose either, it might be more useful for the odd bit of drag racing, maybe with a long wheelie bar fitted?

[niterida]

Not sure from your reply if you understood what I meant, so please don't take this the wrong way if you did. And if you understand it better than me then I apologise in advance for trying to "teach you to suck eggs"

I was thinking of the gyroscopic effect of the crank - a spinning object is very hard to deflect from the radius it is spinning in. If you hold a spinning bicycle wheel by the fork nuts (without it being attached to the bike of course) you can feel how hard it is to tilt it over - it wants to stay upright. So a spinning crank is the same and having it so high up will possibly cause it to be even harder to tilt or lean the bike over. I'm no engineer though so I am only guessing about this but it is something I would look into further if I was building this.

[turbeam]

Yes, I did get what you meant by having the crankshaft positioned so high up and it is a very good point. I think that you are right on this in that the higher up it was to sit in the frame the less inclined the bike is likely to be to want to lean over in cornering. If you think about it though, a bike leaning over at all is partially to counteract the centrifugal effect that its total mass turning through a corner has, and also to put more of those loads directly down into the tyres. Any increased resistance the bike has to being canted over will also probably influence the effect that centrifugal cornering loads will have on it too? I'm not at all sure exactly what the outcome will be on this......in reality the crankshaft centreline will only be about 200mm higher in the chassis than the Hayabusa crankshaft was... time will tell!

On the other hand, the crankshaft itself is probably a bit smaller and less massive than might be imagined, and all of this also affects the flywheel/ gyroscopic effect. Being a V6 the crankshaft is already quite short, but its design also features very slim full circle sections between each pair of cylinders and between the crankshaft bearings that are basically there only to carry ring seals (that look very like piston rings) to seal off the lower crankcase haves from each other so as to provide primary compression to the individual cylinders. I will take and post some photos of the crankshaft and the crankcase halves which will better illustrate this. The crankshaft's own internal flywheel masses, although still full circle, are muych smaller than you would expect to see on a typical bike two stroke crankshaft.

In the original outboard motor, this lightweight crankshaft then requires a large and heavy flywheel on the top end that also doubles up as the starter ring gear etc. Being a 60 degree V6 2-stroke though, the engine is already naturally pretty well balanced and really only needs a flywheel for low rpm momentum reasons. I won't be using any crankshaft end flywheel, and the primary drive gears I will use are only of about 150mm diameter and have a relatively small mass. The ignition/ injection trigger wheel going on the other end is so light it is barely worth mentioning.

If the engine was positioned roughly rotated by about 180 degrees instead, by the time inlet runners were added to turn the intake route from forward mounted throttle bodies and filters up into the reeed valve blocks ground clearance/ frontal space would be very tight. This arrangement would also make the positioning of fuel injectors much more difficult. The engine design's addition of the reed valve blocks onto the lower crankcase half probably adds more height to the basic casing size than would be imagined too, that is the down side of not having air metering or reed valves mounted next to each cylinder bank.

The other thing I forgot to mention is that the required external dimensions and volume of each expansion chamber is fairly large.... think 350cc single cylinder motocross engine system..... and I then have SIX of them to package on the bike. If these all erupted from the exhaust outlets roughly in the position of the lower rear end of the fuel tank it would be very tight to get them all under there and to have them all of the required length.

I do very much appreciate your ideas and input on this though. Some of the problems that I'm likely to encounter on this project I probably am not even aware of yet and will have to solve as and when they are found. With this kind of thing I normally just try to jump the very biggest hurdles first and then solve the others as I come to them, it is almost impossible to plan far enough ahead to be able to see all of the other issues that will surely raise their heads at some point. That is partly what makes it all fun though. At the most basic level though I'm fairly happy that the current engine positioning is probably the best compromise.

[niterida]

Any updates ? Would love to see this beast finished B-)

[turbeam]

Hi all, sorry I've not been on here for quite a while as I've been up to my eyes in other things that have demanded most of my time, and back in November my dad had a nasty fall and broke his hip, which has meant a lot of running around back and forth to hospital etc for me.

Despite this here has been some steady progress in this time, though more on some of my projects than on others.


It turned out that the failed panhard rod on EGA in september actually caused a good bit more damage than I'd first thought. Other than replacing the knackered rear dampers which had been trying their best to provide lateral location for the axle and suffered badly for it, I made a new panhard rod out of 35mm OD tube which I calculated should be just over two and a half times stronger than the old 25mm one....



Some of the floorpan over the axle has been damaged to the point that I want to cut it out and rework it to give a bit more clearance. Even the rear brake lines were flattened.

This photo was taken on Test 1 (Barony Gravel) at the start of the day.....



Amongst other things, the smooth, fast and open but 'crested' roads on an event we did on the Isle of Skye last year had highlighted an old problem with the silencers grounding out on landings following a 'yump'. One silencer had worn right through its rolled end flange joint and the other wasn't much better, so after a basic stainless steel welded repair some skids and wear pads were added to at least help slow down the wear rate a bit!...



Anyway, I had been asked to display EGA in the local Braehead shopping centre to help publicise the 2015 Paisley start of the Monte Carlo Historique Rally, and I was also due to take part in the Heritage Run to the first passage control at the 'Borders' on the 28th of January, so time was tight to get everything on the car sorted in time.

Here EGA is on display on the saturday before the event... note that despite all of the Super Oscars that the car is still in tarmac spec and not the long travel/snow set-up that it had fitted in 2013 for actually going over the snow covered Cols to Monte Carlo...





Still a few outstanding things needing done on it.

No actual progress has been made on the BMW V8 powered car either, but I've had a few other ideas on it, including using a double UJ steering linkage developed for rally cars in place of the normal rubber flexible rubber disc. This gives a good bit more space for the offside exhaust manifold around the steering linkage.

I am hoping to make a good bit of progress on the V8 car in 2015 though, as I have a bi-annual european event in mind that I'd really like to enter in it in 2017.


Over the holiday period, whenever I've had a spare half hour or so I've found it most difficult to drag myself away from the Black Max project though. On this one things have taken a significant step forward.

The first thing that I had decided to do was make the permanent engine mounting plate which I could now copy from the thinner steel template to more accurately locate the engine in its new frame. Some further tweeks were needed to cope with the extra thickness of the 15mm alloy plate but generally the steel template copied over to it well.

Made to fit the engine fixings and carry stock Mercury crankshaft oil seals...



...and trimmed back to clear the offside main frame member....



It could then be used to secure the engine in the frame. This same plate would also be used to mount the gearbox to as well as support a bearing for the jackshaft/crossshaft that would take the drive into the clutch basket via a slot in the upper casing....



The original idea was to take drive fronm the nearside end of the crankshaft with a pair of primary drive gears like this, but that idea may now have to be revised a little....



Here's another view from a different angle, note the radical alteration of the block around the position of what used to be the exhaust outlets in order to to look more like a bike unit as well as saving a little bit of unnecessary weight. The area close to the edge of the plate might look a bit strange in the photos as I gave it a mild polish to see how closely the T6 alloy material would match the anodised frame, but I haven't yet decided whether to polish it or paint it along with the gearbox in Mercury satin black enamel....



...and from fully front-on....



Anyway, I had a hunch that a scrap/ knackered plain-bearing GSX750ET crankcase set that I had lying around used the same gearsets as the old roller-bearing crankshaft GS1000/GSX1100 engines. The bearing and bolt arrangement on the 750 was a bit more compact and better suited if this was the case, plus it would save me having to cut up one of my valuable roller -bearing type GSX1100 crankcases.

A direct comparison with one of my spare set of GSX1100 gearbox internals proved this to be the case, and although there were some clutch differences the gearboxes themselves turned out to be fully interchangable.... here the 1100 parts are on the left with the slightly rusty 750 ones on the right in both cases....



Armed with this knowledge I cut down the GSX750ET lower crankcase, laid in the GSX1100 gearbox parts, and offered it all up in the frame behind the Mercury engine...



This allowed me to temporarily refit the stock Hayabusa swinging arm and rear suspension to check the gearbox sprocket location in both planes. With some further tweeks to the casings, it was possible to get it spot on for chain alignment, which was just as well since there really wasn't a lot of room for adjustment....





The top of the gearbox casing sits a good bit higher than I was expecting, which leaves very little space for the primary drive cross-shaft. At least when the gearbox is also permanently mounted in the frame I will have fixed positions to work from for these sort of things.

I also had thoughts on mounting an alternator, starter motor and water pump all in the space above the gearbox and driven off of the crossshaft too, but this is now looking like a tall order.
Space for the carbs/ throttle bodies and airbox is starting to dictate that all six expansion chambers will most likely now have to be run beneath the engine, but that may be no bad thing. I can't figure out just yet how I could get two of them to then rise and come out from beneath the seat unit, but it is early days yet. On the plus side, no expansion chambers running above the engine might simplify the location of a coolant radiator/s above the upper cylinder bank?

I hope this hasn't been too much of a photo-fest, but with things like this a photo really is worth a thousand words.

[turbeam]

I meant to put these photos on earlier but missed them out. They are of poor quality and taken on my basic point-and-shoot camera, but they at least give an idea of how the parts come together.


The first is of the gearbox sprocket looking froward from along the side of the swinging arm. The Hayabusa swinging arm has a synthetic rubber/ plastic protector fixed to it to prevent the chain marking its soft aluminium and alloy material which has a central rib moulded into it. This was very useful for gearbox sprocket alignment without having to install the rear wheel and sprocket.....




Having the swinging arm in position with the original suspension also made it very easy to get the sprocket in horizontal alignment by projecting a string forward through the swinging arm pivot and wheel spindle centres. Making allowance for the suspension being unloaded like this, the sprocket height was spot on as it was....




The last photo shows the cut-down bike crankcase (now only gearbox) halves positioned in the frame behind the engine. This pic gives a truer impression of just how compact the big Mercury outboard motor really is.... it actually looks quite small in comparison with just the gearbox.... and it also shows that the gearbox upper half sits higher up in the frame than I had imagined it would. This means that it could be a bit trickier to get the primary drive cross-shaft at a height suitable for a gear mounted on it to be able to drive into the clutch basket gear without fouling on the main frame side member/s. That is the main problem with using a modern alloy beam frame that is so much lower at the swinging arm pivot end (and much stiffer) than older types.

I already have a couple of ideas in mind to get around this issue, but I can't make a final decision on it until the gearbox is fully mounted in the frame and to the engine....

[turbeam]

A little bit more progress was made on the new primary drive arrangement which should help explain how I plan to do it.

Firstly, I needed to cut the original primary drive gear off of a GSX750ET crankshaft. The advantage of this is that it has exactly the same pitch and width as the equivalent GSX1100 gear but is considerably smaller. The GSX750ET clutch basket also has a larger driven gear than the 1100 to keep the centres the same, so if I deliberately used the 750 crankshaft gear with the 1100 clutch basket in the 750 casing, the centres would be closer than normal.

750 crankshaft gear removed...




This is how it can then mesh with the 1100 clutch basket gear...





And in roughly the position where it will be in mesh with the clutch basket gear through a slot in the upper gearbox casing....





This photo shows the first-stage primary drive gears on the crankshaft end. The new jackshaft will transmit drive between these two gears and itself run in bearings fixed inside the engine mounting end plates. Oil-tight casings can then be formed around the gears with oil seals on the new shaft, which will be made in aluminium alloy and welded directly to the gearbox casing....




This pic is of the first stage (crankshaft end) primary drive gears. The 'sharpie' marks on the frame show roughly where the lower outside corner will have to be 'cut-and-shut' a little to give clearance when the gear is raised to the correct position to suit the jackshaft centre. I had hoped to avoid altering the frame like this, but needs must...

[v8]

I'm loving the two stroke V6

Keep the pics coming

[fer4l]

Similarly in awe!

[turbeam]

Well, today was a bit of a milestone on this project as it didn't go exactly as planned and needed a bit of a rethink!

First job was to remove the gearbox casings again, which also needed the engine to come back out, so I knocked up a couple of new lower rear gearbox mountings in 15mm thick T6 alloy and 'heavily tacked' them into the frame to make sure that the gearbox would go back in again in exactly the same position....





I also wanted to start getting ready with some means of physically joining the gearbox to the engine so that in future the two could be installed as a single unit (much easier), so a few more tweeks were made to the block to allow an 8mm thick piece of alloy angle to be tailored to fit on its original crankcase/ block joint fixings.....




The idea here is that this will be welded directly onto the upper gearbox casing so that the two major components can be slid together and bolted up. When the angle was bolted on the engine and gearbox were reinstalled in the frame, this time with the input shaft fitted so that the clutch basket could be held centrally to give an accurate position for the smaller gear driving it....




It was around this time that things started to deviate quite a bit from the original plan. With the clutch basket driven gear noe in the picture, the smaller 750 drive gear still wasn't able to go as far forward as I had estimated. In the following photo this is as far forward as it will go without cutting into the reed valve chanmer, which I REALLY didn't want to do, so this m,ore or less dictated the gears final position..... about 25mm further back from where I wanted it. MMmmmm......




In this position the gears I was going to use had their centres too close together. The crankshaft gear was already about as big as it could be without fouling the frame, and its larger partner would certainly foul the frame even more than I had allowed for if an even larger gear could have been used instead. This would have had a detrimental effect on the primary drive ratio too.

I considered using a HyVo chain instead of the gears, but its upper run would then need a straight-line cut out of the side frame member for clearance that wouyld have excessively weakened it.

I thought the best solution might be to use a third idler gear to allow the crankshaft (drive) gear and the jackshaft (driven) gear to be spaced with their centres at whatever separation I wanted.

I decided to mock up the true jackshaft centre position to let me get an idea of how much a gear mounted on its left end would likely fpoul the frame member on that side....





It looked to work well enough in clearing everything of importance, so I bit the bullet and cut a partial recess for this gear into the frame member which can be shut again later once an the gears are all permanently mounted and an enclosure has been flormed around them......











I wasn't hugely keen onusing the third idler gear like this, but it does have a couple of advantages. The 'first stage' primary drive ratio is now back to 1:1 again, with a minimal sized relief of the frame, and allowing whatever gear centres I like. The engine width on this side is still no greater than on the other side due to the way the two cylinder banks sre offset.

I'm now planning on using the original Suzuki oil pump (driven from the cluch basket gear) to supply a pressure feed to the centre plain bearing of the idler gear, which will in turn give splash lubrication to the gears and jackshaft ball or roller bearings before returning back to the sump below the gearbox.

[georgeb]

Stunning work going on in this here thread. I'd forgotten about it until now. Bookmarked so I don't again.

[neilios]

I agree, great work on a wide variety of project. Keep the updates coming as it offers inspiration to all.