That picture has the truck intake which is about 4 inches higher than the smaller intake. as far as the bottom end I can fabricate a subframe with clearence where it needs to be.

 

I know nothing about the skyline.... when did they start using a torque tube setup?

 

No, you can't. Well, I suppose if you only need 1/2" of ground clearance, no steering rack and run 8" diameter wheels to get the hub centers lined up with the differential, you could. Thanks for clearing up the part about the truck intake, I had no idea what the engine setup was after the previous 8-9 LSx motors I've built. I didn't say the "top of the intake will be 6-8" higher"; I said the ENGINE is 6-8" higher, and that's being optimistic. With the LQx/L92 intake on it, you're looking at 1' or more higher. You also have to take in mind custom frame rails (axles need to be where the stockers are), dual a-arm or revised layout McPherson front suspension (there is a McPherson strut assembly and swaybar mounting setup in the way of your axle currently). The list goes on...

Anyway, I'm done here, back to your fantasy world. Good luck with your "swap".

 

There is no torque tube in that picture. Torque tube = fixed hollow tube with a driveshaft inside of it. The picture linked above just has a rear transaxle with a driveshaft from the motor and a driveshaft back up to the front diff. If you look closely, you can see the u-joints on both driveshafts.

 

Just need to get out there and start measuring things I guess but I think your being closed minded. You cant customly fabricate something being that way you have to have a little imagination and ideas. im not looking for ways it will not work im looking for ways I can MAKE it work. so yeah just my .02 cents.

 

Hmm... I know that the torque tube started like that but i was going off either Audi or Alfa Romeo can't remember who, but they had a front engine rear transaxle set up like that and they called it a torque tube "The torque tube will allow power transfer directly to the frame of the car with out loading the suspension giving the car a more responsive feel as well as giving better traction." and it lacked the physical torque-tube tube.

but the principle is the same as a torque tube even if it is wrong to call it such. Torque tubes are to allow the torque of the wheels to act on the car not suspension and if you look at the rear if it where a traditional drive line the car would have a **** ton of squat under acceleration.

 

You're right, I'm close minded, and could never handle custom fabrication. Here are a couple examples of that close mindedness.

My single turbo LS1/FC. I designed and built the turbo system, custom Dana 36 rearend, custom electrical system, custom gauge panel, custom seat conversion, and quick release front bumper:





Twin turbo LS1/FD. I designed and built the turbo kit, fuel systems, brake systems, cooling systems and custom gauge panel:



I'm not close minded, I have an engineering background and experience in motorsports and design. What you want to do can absolutely be done. To do it in a well designed manner is going to mean completely re-engineering the car. The drivetrains you're discussing are not a feasible option. That's not close minded, that's mathematics. The more important mathematics are the ones that start with dollar signs, and I don't think you have any idea how big those numbers are to engineer and fabricate something like this. Here's a tip, there are four zeroes, and it doesn't start with a one.

edit: BTW, take a look at the center line of the wheels vs. the center of the crank pulley in the FD picture. Your half shafts need to be approximately level at rest. Your diff needs to live where your crankshaft is. You don't need a measuring tape to see the issue.

A torque tube rigidly ties the engine to the diff or transaxle. This keeps the diff from moving separately from the engine/trans. You get a somewhat similar result with a transaxle, but that doesn't make the driveshaft a torque tube.

 

I understand what a torque-tubes tube is and where and how it is installed, I have worked on a hand full of corvette's and 944's. But you're response had little to do with what I had posted and i think you are misunderstanding what i am saying. Why do they use a torque tube drivetrain? It's not to help the weight distribution of the car, its just the icing on the cake. It also has nothing to due with letting the engine and trans move separately, this is just a side effect as there are not a lot of good ways to transfer driving force from the trans to the engine to the frame that would allow the trans to move free of the engine. http://en.wikipedia.org/wiki/Torque_tube. with how the front and rear diff/transaxle are bolted and the design of the suspension the Skyline looks to work in much the same way with loading the drive force on the frame / body and not the suspension so

 

The result is somewhat similar to a torque tube, but the principle has nothing to do with it. It's only because of transmission mass and torque multiplication. I'm really being pedantic here, but it's true. Putting the transaxle out back is less similar to a torque tube than an IRS or solid axle with a torque arm from a chassis loading perspective. An FD or a Camaro (1993-2002), both of which have torque arms, and are much closer to a torque tube in function than the Skyline shown above.

If there is ANY play between the chassis and the transmission in the Skyline (and there is, it is rubber mounted) then you have chassis loading. At that point, the only major difference from a normal front mounted transmission IRS design is the torque multiplication applied to the chassis (since it's getting 1:1 torque at the transmission and diff with the transaxle, where a seperate trans and diff gets the torque multiplication by gear).

I understand your point, but it just isn't quite correct.

 

Let's see, if we sacrifice an inch or two of ground clearance, we can BARELY get the headers on the car and squeeze some carefully-angled piping next to the tranny in the tunnel. A little grinding and hammering away at the body and we have a very tight-fitting exhaust system on our V8 FD.....now let's throw a wider transmission and an extra driveshaft in there just for fun! Yeah, not happening.


Yes, it can be done, but by the time it's done, you could have bought a pretty damn serious AWD Porsche 996 and a Boost Logic kit to make it walk all over the FD. Actually, considering how long this would take, the 997 will actually be had for cheap in the used market. Let me guess, you want a TT kit on your AWD FD, too?

 

You're just not thinking outside the box. Unfortunately, in this case, the car is the box, and outside the box (car) is where the differential will be.

 

AWD only has an advantage in the wet tarmac and on the dirt/gravel.
2 exceptions.
- High horse power cars only awd has advantage on slow corner exits.
- touge where road is more of a rally with dirt and leaves


other than that it is useless.
RWD can out lauch awd cars with proper tires and suspension even if the awd has proper suspension and tires.

rwd wheel be simpler/lighter/turn faster(weight advantage)

Your breaking will be better again because of weight.

Not to mention you will be intalling a v8 that will raise the low center of gravity our little rotary kegs provide. less turning capabilities.

 

How much it is raised (look at the crank centerline in an LS swap and remember that the vast majority of the weight in the drivetrain is right there) and the extent of damage to turning capability caused by the slight variance in polar moment is really debatable, though I will agree that it does alter it. If you look at the picture above, the entire transmission and almost all of the engine weight is between the bottom of the crank pulley and top of the water pump pulley. The rotary does not sit dramatically lower in the chassis.

That said, this guy likely doesn't even have an FD. Another dreamer with more mouth than money. If he does have an FD, he might want to consider popping the hood before he spouts off about his plans, eh?

 

^^ im sure it wont make to big of a diff.

Even worse if you use an older 350 with iron heads or something. But with modern all aluminum lsx's it cant be much diff. But i do think the 13b's sit in there in mid ship position. 13b's block sit completely, if not the majority, behind the front axles. DO v8's do that?

The mroe weight in the front the worse the car becomes for circuit.

I always kinda doubted the fact that v8 swaps weight the same.. Seems like they measured the 13b fully loaded and weighed the v8 bare without accessories.(ac/ps/alt)
But i have not done the swap nor weighed them myself. so i dont know for sure. But i would like to do my own research before taking other peoples word on the v8's weighing the same.

 

*Sigh* what make's a car a front midship?

 

Love it.

 

Im a bit confused on your FActs.. so a 13b-t block. SHort block. no more than flywheel and water pump weigh 370lbs or 210lbs? so its 210 short block and 370 long block?

ANd could you specify what items were still on the "long block" ls1
and the items on the long block and short block for the 13b?

Is there a thread somewhere with pictures and all and full documentation on the weight diff's?



I mean have you ever looked at the short block alone in the engine bay.. no manifold or anything? just the keg in there. I have never swapped a v8 in an rx7 so i dont know how it fits in there. does the v8 sit that low?

How LOWW it is.... thats what im geting at. the engine might weight the same. but the majority of the engine weight ,including the turbo, are down there.

 

YOu know what i really dont care cause this bacause its about pushrods engines..

IM done talking about v8 swaps. here dig this.

http://www.youtube.com/watch?v=fxv2uEYD6JM

 

The V8 does have more of the engine forward of the axle centerline vs. the rotary, no doubt. The catch is that most of that (I'm only talking LS1/2/3/6 here) is aluminum. The block + tranny itself (fully dressed) is negligibly heavier vs. a turbo 13BREW (fully dressed), something like 20-30 lbs, but a fair amount of that is in the much beefier T56 transmission, which sits very low and back in the chassis. Most of what is higher than the rotary in an LS swap is the plastic intake and the top of the heads which are hollow aluminum. The big weight of the engine is in the crankshaft, which is VERY low in the chassis (centerline is just a few inches above the steering rack).

Regardless, it certainly does cause some small changes in chassis balance, but it's nothing that cannot be tuned out with some very slight suspension tuning. Honestly, if you're pushing a car hard enough for that to matter, you really should be tuning your suspension anyway.

I've been in a lot of rotary and LS swap cars (FC and FD). The positions of the engines are a little misleading in pictures. A shot from each setup from right in front of the car, with the cylinder heads off the LS engine would make it more clear I think.

Anyway, it's a moot point since we all agree the original poster lives in la la land.

 

I can see the trans being most of the weight.... i dint think about that. I meaning a lot fo the weight is in the tranny tunnel.

And suspension tunning is always second to tires. for anyways.

 

Tires are important, but tires can't change vehicle balance (well, without changing stagger/compound). Besides, I'm assuming again that someone with that much thought into vehicle balance isn't running Blizzaks at the track.

 

The weight of an LS1 with PS, no ac, no exhaust manifolds, no flywheel, no alt is probably right around 410-420, I just shipped one a few months ago that was 448# on the scales attached to a pallet.

Engine to engine I know with another person I can remove a rotary as a bare shortblock, I definitely cant do that with an LS1, but where the LS1 will make up a lot of ground is in the trans. I can easily install and remove TII trans laying on my back, while doing the same with a T56 I can barely keep myself from getting crushed. Im going to assume the T56 with bellhousing is in the 150-160 range, while the TII trans is probably a little more than a 100.

The wheel centerline picture is a little misleading, because the LS1 is even shorter than a regular small block, granted on a like an inch or 2.

As far as AWD is concerned, digital solo is correct in the fact the you would have like a 1 foot cowl hood to be able to fit that thing, and then the trans tunned would be at your shoulder. not to mention trying to be able match a manual transmission to that transfer case. Its an engineering nightmare and the costs would be impossible to estimate. If you want a wicked AWD car find an R32 GTR or build an EVO, most other things are not feasible. I'm not going to knock subarus, I love those cars, but in building a monster, its hard to keep that boxer engine together.

Basically if youre a person fretting these details, youre on the wrong platform, people pick the LS1 V8 because its $ to result is unbeatable. If youre wanting to build a real car, someone needs to be stepping up to a real platform like a C5, C6, Viper, or 911

 

or u can just get this http://www.youtube.com/watch?v=_Ru4ybNpJ1g o wait he drop the awd and went with rwd

 

it doesnt look like that really fits, theres no room for an airfilter

 

Difficult; maybe, impossible; no.

It would be a different and with enough $$ anything is possible, but would it be worth it? I dont know if I would undergo such a project unless it was to represent my own or a friends shops fabrication work. Although if one were sitting already done I would gladly jump in the cockpit lol.

To the previous poster, Skylines are unreliable money pits and Evo's are well,, their Mitsubishi's. Ive had plenty of wrench time on both, and have built and swapped a few RB powered vehicles. Matter of fact the most money Ive ever dropped into a stock engine and it remain stock was an RB. Im not just speaking positively about Subaru's because I own one, but my STi is 1 car in an ocean of Mitsu's (locally), and most of those are usually on jackstands half the season. They handle power alright, the difference between the Suby's and Mitsu' is the Suby drivetrain can handle everything the engine can. Mitsubishi's cant even handle the stock power haha (bring the flames on lol). Im not knocking them, their gorgeous cars but I dont know a single Evo owner that doesn't have lots of money dollars invested annually just to keep their car running, stock or otherwise. In the end their all machines though, and I'm a firm believer in anything organic or not will eventually die lol.

Back on topic though I would think the main disadvantages of the AWD RX7 setup would be the things we covet most about our cars but the project done right would go a long way to promote a shops work.

interesting thread idea and concept though.