Project Madera: A Jimmy GT

[skorpioskorpio]

LOL, I'm bettin' that engine cost a bit more than my engine budget, matter of fact I'm betting I could buy a certified pre-owned V-12 Astin-Martin, throw away the car and be cheaper. That looks like Ryan Falconeer kind of cash.

[watahyahknow]

there is actually a 3 liter 24 valve version straight 6 made of the older CIH opel engine called the C30SE that was fitted in the omega
https://www.youtube.com/watch?v=A0HtdtOUG5o
those where available with manual gearboxes as they where made for DTM racing

seen a 2004 subaru legacy 6 speed transmission a while back that had the starter comming in from the gearbox side intoo the bellhousing ,

said to be good up to 450Kw
thinking about that it would solve some of the problems if they would make a belhousing that would fit a strong enough box and mount the starter in the bellhouse itself under the transmissiontunnel instead of against the motor

[skorpioskorpio]

For transmission I'm doing a paddle shifted 6 speed 4L80E. Going to mill off the bellhousing and do an adapter plate on the pump to mount the 4L65E Bellhousing.

[truckeez]

hmm,, that looks tasTEEEE ide like a 3.6 version with those Loooooooooong runners, obviously the work of Lotus.
http://www.club-opel.com/owner_car_photo.php?id=6270

Originally Posted by watahyahknow

there is actually a 3 liter 24 valve version straight 6 made of the older CIH opel engine called the C30SE that was fitted in the omega
https://www.youtube.com/watch?v=A0HtdtOUG5o
those where available with manual gearboxes as they where made for DTM racing

seen a 2004 subaru legacy 6 speed transmission a while back that had the starter comming in from the gearbox side intoo the bellhousing ,

said to be good up to 450Kw
thinking about that it would solve some of the problems if they would make a belhousing that would fit a strong enough box and mount the starter in the bellhouse itself under the transmissiontunnel instead of against the motor

[skorpioskorpio]

I've been working on the design lately for the intake manifold. I've abandoned the idea that I can mill this, as it turns out, in order for me to get the relief cuts I need it requires impractically deep cuts on small diameter fluted mill ends, oh well.

So I'm back looking at castings, talked to a casting model maker late last week and he gave me some good advice, though the best advise was the name of a company doing precision lost media casting. I only really need one of these so making a model for sand cast cores is cool and all, but unnessisary. Simply doing a lost media displacement cast seems like the ticket. I've submitted my design to them already and they will be reviewing it this week. Casting gives me so much cooler of a piece in the end, and lost media casting is really cool in that there is no parting lines or anything, just a pure version of the design. Here is a few render views I did of it:




I had to squish the port spacing on it on the carb/throttle body side to clear the alternator and to allow me to push the engine into the firewall recess without having to create some big notch in it for the carbs and airfilter. The ports are not strickly equal because of this but I have some independent adjustability in the stacks so I think it'll be just fine.

Next step now is the pan bottom design, which I'll be starting today. I've been told I should have a cut core for the transmission soon and I can do the design for the 4L80E pump to 4L60E bell housing adaper plate which I can't do until I have a cut case because it's not strictly just a flat plate. The 4L80E has 3 pan bolts and the pan flange that are actually forward of the pump face and need to be milled around and left in place, so the adapter plate needs to take those into consideration. There is also a passage boss in the pump itself that needs to be milled around but all really doable and not dificult on a CNC mill.

[watahyahknow]

you mean a case saver bellhouse like they used on the older th350 400's and powrglides
https://www.youtube.com/watch?v=HL93XAc4MGs
oh hang on adapterplate to the pump then stock 4l60e belhousing , forgot those are split cases

[skorpioskorpio]

Yes, exactly, cut off the bellhousing make a pump adapter plate for the 4L60 bell. The 4L60 bell is surprizingly similar to a Reed bellhousing which is what is usually used in such things.

[watahyahknow]

you could make the lost cast (wax?) on a 3d printer and give that to the foundry to cast in aluminium
i believe you need to make it a little oversize as the cast aluminium shrinks a bit after pooring (talk to the foundry to get the exact percentage )
you could allso make it in some sort of plastic and mount it straight to the engine , thats been done before too

from the looks of this pic you might even be able to print the trottlebodies so you just need some bronze bushings a shaft and butterflyvalves

[skorpioskorpio]

The manifold is a DCOE Weber pattern, so can be used for Weber carbs OR DCOE pattern throttle bodies (which I already have, Jenvey Dynamics ones). Lost media casting is lost wax, same thing and it will be 3D printed on a wax printer. The shrink factor is 1.014:1 for investment cast 356 Aluminum which I haven't added in yet, but it's not a big deal, but need to know how to calculate it because it's non-linear and it's a long piece. Cored sand cast has quite a bit more shrinkage and tends to bloat more which is another reason lost media is more desireable.

I was told that you can do pours directly with a plastic master, but some of the plastics are quite gassy and the resulting castings tend to be more porous and a lot weaker.

3D printed plastic, at least on a printer with affordable media, tends to be low melting point stuff, I mean that is how these printers work, so wouldn't work well as printed, also it's not really structurally tough stuff either and there is a lot hanging off this manifold. Your talking almost a foot worth of stuff and way out on the end is a big hunk of foam soaked in filter oil.

None of the printers I have access to can print the manifold in one shot it'll be probably 3 sections pieced together because thet is how it works out best for joining the pieces.

[skorpioskorpio]

I wasn't going to mention this piece until I had it in my hot little hands, but now it is, and here it is:



Brand new and uncut, straight from Boneyards mold. Some assembly required, I'm pleased as could be. I asked Kurt to send me one unassembled, I am going to look onto maybe recessing the rear window and using surface mount glass to make it flush and proabably put a wiring channel in it as well as sound deadening in between the inner and outer skins.

[jjzepplin]

Is that fiberglass? I want one!

[skorpioskorpio]

Yep Fiberglass, from the original MTP molds.

[jjzepplin]

What does one of those run? If you don't mind me asking...PM me with some info. I didn't know any one was making them.

[Boneyard]

Thanks, Ken. I'm glad you're happy with how they turned out.

[skorpioskorpio]

I've been through lots and lots of headaches with this build, but when I dropped that top on so many things were just right. It took 3 guys to cart away my old top, this little light top was so easy and it just dropped into place. I know it's unassembled and I know it has no glass yet, but I'll bet it drops a couple hundred pounds from the truck and won't make a lot of difference in the weight bias on or off. Certainly not something you can say about the original! Also with the Recaro more reclined then I'd ever drive the seat went back to it's farthest position, a position I at 6'1 wouldn't be able to touch the pedals at, roomy. The seat angle of the Wedge Engineering brackets helps out with that a lot.

My big ol' Suburban was never roomy in the drivers seat despite the truck being big enough to house several armies of clowns. ...and it is on this note that I tip my hat and say goodbye to that Suburban today. It was a great truck, but I hadn't driven it in 6 years and it was time. It had driven up and down both coasts and it will now head for another on the other side of the Pacific. I had several offers from guys who wanted it for the drive train and part out the rest, but I decided instead to sell it to a guy who will be sending it to Japan were I'm sure it will still be running and cared for for many more years. Maybe it'll still be known as Aurora there.

[skorpioskorpio]

Here is some pics of the case for my soon to be 6 speed 4L80E, first as I got it from the trans guy, basically lopped off with a plasma cutter and "Cleaned up" with a die grinder:

I cleaned up the casting snots on the top of the case because they were provoking me:

Had the machine shop throw it on the mill and clean up the front to make it even and parallel:

Bolted on a deep cast aluminum pan:

...and dropped in the pump which is where the "plate" will bolt onto and the 4.2's 4L60E bell housing will bolt to it:

Still need to have the outer ring of the pump milled flat (except there the oil galley protrusions are).

[skorpioskorpio]

Oh and as a reminder, this is the milled oil pan for the 4.2 (with the Fiat 500 sump clamped onto it) bolted to the specific 4L60E bell housing that is getting adapted to the 4L80E:

And the Nardi wheel with the Twist Machine paddle shifter on it that will shift the 6 speed 4L80 when it's in manual mode:

[jlsanborn]

Cool stuff!

[jbclassix]

Wait.... 6 speed 4L80?!?! Do tell more

[watahyahknow]

they do that bij changing the oilflow inside they clamp more that one band to make ratio's between the other gears
1
2
2and 1
3
3 and 2
4
or sumtin like that

[skorpioskorpio]

An over simplified view is that a 4L80E is essentially the TH400 design hacked to be electronic and an overdrive planetary gearset added to it's 2.48 1st ratio and 1.48 2nd ratio, 3rd is direct drive and in the 4L80 OD is .75. How you get 6 speeds is to engage the overdrive to every gear and not only to the 3rd, direct drive gear. So you get 1st, 1st+OD, 2nd, 2nd+OD, 3rd, and finally the 3rd+OD that you get normally in a 4L80. This is all done in the valve body hydraulically, and all the clutches and bands are the same as a normal 4L80. Of course you need a TCU that knows this modified valve body exists and there needs to be the supporting electronics in the trans to make it do this. PCS makes both the valve body and the controller, TCI makes a similar setup pre-assembled, however the TCI trans does not engine brake on down shifts the PCS setup does within certain rules.

Problem is that the 2.48, 1.48, 1.0, 0.75 gearing doesn't really give you 5 well spaced gears, so TCI created new 1st and 2nd planetaries with a 2.98 and 1.57 ratios which gives nice even gear spacing through the 6 possible gear ratios and increases the total gear ratio spread from a 3:1 1st through 4th to 4:1 1st through 6th. It ends up being a 6 speed trans with closer gear ratios than a stock 4 speed configuration while increasing the overall ratios bottom to top. In combination with rear end ratios it essentially gives you an extra gear on top or an extra gear on the bottom with 5 closer gears in the middle.

because the ratio drops are less, you can get the torque converter into lockup quicker, need less stall and the PCS controller will auto shift with multiple programs or go into full manual mode. So you can have a smooth touring auto shift program, a more aggessive "sport" shift program, and the manual paddle shifting. Torque converter lockup, shift points, trans pressure are all under the control of the PCS TCU and are tied to RPM and a Throttle position sensor (TPS).

There are still only 4 mechanical detents in the trans and some of the lower downshifts require a mechanical detent for engine braking though more simplistically the trans can be shifted fully electronically, it'll just freewheel on certain low gear down shifts (like all the new 6 or more gear automatics do). I was told by PCS that only 1st +OD to 1st and possibly 2nd to 1st +OD freewheel. However if these gear ratios are shifted to via mechanical means they will engine brake, so I will be using an electronic shifter that converts these shifts into mechanical events through a cable via a servo motor. The normal P-R-N-(D)-D-2-1 still needs to be present as the paddle shifter only shifts forward gears, and in my truck will be a push button + display panel for this function.

In the end I should end up with a trans that shifts, maybe not quite as fast as the double clutch exotics but way faster than you could ever shift a manual, and be in torque converter lockup almost all the time because of the low RPM drop in the closer ratios. Configured with the equivelant of a 4.11 gear rear end ratio to the "normal" 2.48 1st (which in the 6 speed would be a 3.50 rear end ratio, it puts you at 80 MPH at 2700 RPM in 6th and at 5000 rpm (way short of readline on the 4.2 which redlines at about 6500 or could be pushed to 7500+ with a different harmonic dampener) will push the truck to just shy of 150 mph, probably getting towards the limit of what a Jimmy can do aerodynamically, it is a brick afterall.

[watahyahknow]

i think the first aftermarket company that will make one of those (now) exotic twin clutch fast shift boxes that can hold 900 plus horsepower available to the general public for an afordable price will do a clean sweep across the whole market for both auto and manual high performance boxes

there expensive still and most likely be realy hard to set up and build in the first place but they bring the power to the ground without interuption through the whole set of gears i think they would be the best boxes for fast et's at the dragstrip bar installing a warpdrive engine from starship enterprise

the only other kind of transmission i think comes close is the variomatic or CVT (the type of gearbox used in scooters) wish revs up the motor intoo its perfect rpm and keeps it there while changing the ratio seamlesly all the way up to topspeed , its a old folks tranny but its a simple desighn and works realy good if they can make it holding 900 plus hp

[skorpioskorpio]

I don't know, there is lots of double clutch exotics out there and they have great 0-60 and 0-100 times, but don't tend to really convert that to great ETs in the quarter, especially considering some of these cars have several hundred more HP than any musclecar ever came with.

...and lets face it big HP is great and all, but the problem is and always was getting it to the pavement. All these new cars with monster HP numbers would chew themselves to bits without torque management and traction control. Most of the double clutch cars and even the 6L90 equiped GMs manage the engine as part of the shift routine to keep the trans from exploding. Not really something you can do with a mechanical throttle, you need drive by wire to make this work and suddenly it's all a whole lot more complicated as an aftermarket package. 6L90 equiped cars briefly starve the engine during shifts so the sudden torque surge doesn't shatter the platetaries, and there are no bands to brake the spinny bits in these. Double clutch transmissions are similar, precise, coordinated shift events coupled with an easing of power delivery.

CVTs, problem there has always been that they are generally the same design, 2 variable diameter pullies, basically 2 cones that interlock with each other and spread apart to make the diameter less and squeeze together to make the diameter bigger. Trouble is there is a mechanical limit to how much variation you can get in this arrangement, the more there is the wider the belt (or chain) needs to be and the less relative contact area there is, meaning it needs more tension to resist slipping, which means everything needs to be beefier, so long before you approach the kind of top to bottom ratios you can get from descrete gears you end up with either a really heavy spinning mass, or something that is prone to slipping. Works a lot better with electric traction motors where torque is all centered in the low rpm range, as this type of trans can be made to slip less at it's limits than in the middle.

Even my trans will require coordinated shifting because of the double shift events that need to happen. for example a "normal" 4L80 shifts from 2nd to 3rd by clamping on the 2nd plantary to stop it and activating a clutch to lock direct drive. In mine the same shift (which is 2nd ratio +OD to the 3rd direct ratio, or 4th to 5th) means clamping the 2nd and OD planetary drums simultaniously and de-clutching direct drive. Should work well with the smooth, almost linear torque curve of the 4.2, in a big pushrod V8 with a high torque hump or a peaky turboed engine I'm not so sure.

[watahyahknow]

think the torque controll is wats holding the twin clutch box down at the moment , actually dont know if they ever be able to make them strong enough to take the full force

you might be able to extend the range of a cvt by using two setup in series so the first belt driving the second making it two stages use heavier springs in the second set so the only start to expand after the first band is extended fully

the real acillisheal of the cvt is the beltstrength if that snaps theres no more drive at all

[skorpioskorpio]

Originally Posted by watahyahknow

think the torque controll is wats holding the twin clutch box down at the moment , actually dont know if they ever be able to make them strong enough to take the full force

you might be able to extend the range of a cvt by using two setup in series so the first belt driving the second making it two stages use heavier springs in the second set so the only start to expand after the first band is extended fully

the real acillisheal of the cvt is the beltstrength if that snaps theres no more drive at all

I don't think there is any motivation to making passenger car transmissions beefier or truck transmissions sportier, especially when. in order to meet fleet averages, you need to add more gears in the same space *OR* make the vehicles lighter. A beefier trans doesn't fit into that equasion. As for trucks the same lightening excercise is going on there and there is no drive towards making high reving trucks, it's about low rpm torque for great hauling and towing capacity and you just don't need a fast shifting trans there.

This holds true industry wide whether you are talking big 3 domestics or overseas exotics. You don't need a big brutish double clutch monster in a carbon fiber exotic that weighs a hair over a ton, even if it has 700+ HP in it.