Manta Mirage build

I have a disease.  It's the "what if" disease.  I can't seem to leave well enough alone. 

I've been looking at transaxle options to hook up to my LS engine.  There are a number of options. Most of them are pretty expensive.  A reasonable priced transaxle with good strength and shifting is the Boxter S 6 speed.  They are in the $2-3000 range. Then you need an adapter, flywheel, clutch. These parts from Kennedy are about $2400. Then you need axles made to go from the Porsche to the C5 Vette suspension.  The problem with this set up is that the gear ratios aren't optimum for the LS.   Some of the reviews of this combo are saying that they skip a gear when shifting. And, that at 75mph the engine is turning over 2900 rpms.  

I've built a few cars over the years with C5 parts.  The C5 uses a transaxle but the engine is in a traditional  front location .  A torque tube connects the engine to the rear mounted transmission.  The transmission bolts directly to the diff.  Unlike most transaxles that have the transmission mounted behind the diff, the Vette's transmission is in front. The torque tube can be eliminated and then engine, with proper bell housing will bolt to the transmission.  

Using all C5 parts keeps cost down and keeps all of the components matching. The down fall is the length.  

l have a couple of more rolls of red duct tape.  So, today I decided to mock up the car with the length necessary to use the C5 parts. The result is a 107 inch wheel base. While it's quite long its the same wheel base as the new C8 Vette.  

I have all of the parts to make this change.  It would require fabricating a new frame.  I would make it so that the C5 front and rear suspension cradles would bolt in.  I've done this before. A 13 inch fiberglass insert to go between the rear cockpit bulkhead and the rear body clip would be pretty simple to use.    

I'm not sure what I'll do yet.  I'll print off pictures and tack them to a wall in my house.  I'll stare at them for a few days.

If I did this I think that I could locate radiators behind the cockpit and re work the nose of the car. Where does it all stop! 

Having fun.  

Note that the wheels sticking out are because I didn't move the suspension to match the extended wheelbase.  

Looks pretty natural. It took me a minute to figure out what was going on.

Did you try the "look" with all of the extra distance just moving the front wheels forward? The back looks a little funny (to me) with so little overhang when the front has a much longer overhang.

Hello Everyone,  It's been quite the winter.  Shortly after getting the Manta home I broke a bone in my left foot.   I dropped a block of wood that I use under the jack of my car trailer on it.  I don't have feeling in my feet and I didn't think anything of it. The next morning my foot was very swollen and black an blue.  Went to the DR and found I had broken a bone.  That laid me up for awhile.  Then I had another issue come up that required surgery.  I've been recovering from that for the past few weeks.  I'm just now getting to the point where I'm thinking of going into the shop.

With my health issues I decided that the Manta was too much for me to take on at this time.  In addition to health I realized that it wasn't going to be an expensive build.  A proper transaxle with gearing for the LS motor was going to be in the 12K range.  And, I was going to have to build a new frame for it.  I had several people contact me saying they wanted to buy the kit.  I sold it last week.

I love my Cheetah Roadster Tribute that I built.  I'm going to concentrate on it.  I have an LS1 that I rebuilt last summer. I'm going to replace the 305 that it's in the car with it.   I also purchased one of Tremec's new TKX transmissions.  The 5th gear overdrive will be a big improvement over the Richmond 4 speed that I have in the car.  I've test fit the LS and TKX.  I will get it level and set so that the bottom of the oil pan doesn't extend below the frame.  I'll run a different intake and headers.  The HP should be 350hp + and the weight of the car with fluids will be just under 1900lbs.  Should be fun.

The other thing that I'm going to do is work on a removable hard top.  I used 1 inch pipe insulation foam to mock it up.  Hopefully nothing else happens to me and I can get back in the shop. 

Sorry to hear about the troubles. Sounds like a great shift in focus. Looking forward to seeing more of the Cheetah

Your timing on getting the new TKX transmission is good.  I have the TKO600, and it has to be warmed up and shifted slowly at 6,000 rpm or the synchros grind.  The trans is not bad; it's just a flaw of the TKO.  The TKX design doesn't have the problem from what I've read.

My Lucra comes in at about 2,200 lbs.  It has a stock LS1 at about 350hp.  With a 2.87 first gear and 3.07 rear, I'm shifting out of first at 6,000 often before I can get the pedal to the floor.  The .64 overdrive is nice on the interstate because the LS1 exhaust note is a low burble out the side pipes and easier on the ear after a couple of hours in the car.

I'm looking forward to seeing how you do the hardtop.  I'm still getting sunburned in mine.

Please document the crap out of this.  Engine weight, powertrain length, width, height, etc.  

Can you give more details on the diy hardtop? Please? This is something that a lot of us would be interested in trying on our open air track cars. Especially since miata hardtops are north of 2k now.

deatonbt said:

Your timing on getting the new TKX transmission is good.  I have the TKO600, and it has to be warmed up and shifted slowly at 6,000 rpm or the synchros grind.  The trans is not bad; it's just a flaw of the TKO.  The TKX design doesn't have the problem from what I've read.

My Lucra comes in at about 2,200 lbs.  It has a stock LS1 at about 350hp.  With a 2.87 first gear and 3.07 rear, I'm shifting out of first at 6,000 often before I can get the pedal to the floor.  The .64 overdrive is nice on the interstate because the LS1 exhaust note is a low burble out the side pipes and easier on the ear after a couple of hours in the car.

I'm looking forward to seeing how you do the hardtop.  I'm still getting sunburned in mine.

I had a TKO in one of my cars.  Your experience is the same as mine.  I was not happy with the way it shifted.  I'm hoping the TKX is as good as it's hype.  We have the pretty much the same set up.  350hp ls1, 2:87 first gear, overdrive (.68) light weight and C4 vette suspension. I think this should be a great combination.

  Do you know what spring rates that your running?

I'm going to start a new thread:  Chesnut Cheetah Tribute Updates to document the new drive train, creating the top and some other changes.  I'll try to post in detail the drivetrain dimensions and weight and other aspects of the build.

If I were to make a hard top for the Miata I would buy one and pull a mold from it.  Isn't there anyone making replacement tops at a reasonable price? 

I'm leaving tomorrow for vacation in AZ.  I'll be back home March 30.  I'll get back in the shop and start posting then. 

Having fun

The Lucra is running 10" 185 lbs. Swift Springs part #100-250-185B on the front.

The rear is a stock 1993 Corvette monoleaf that Google tells me is 228 lbs.

Without the front sway bar the car is tail happy, correctable, and comfortable driving around town.  I usually drive with the sway bar connected.  A rear sway bar is not needed.

deatonbt said:

The Lucra is running 10" 185 lbs. Swift Springs part #100-250-185B on the front.

The rear is a stock 1993 Corvette monoleaf that Google tells me is 228 lbs.

Without the front sway bar the car is tail happy, correctable, and comfortable driving around town.  I usually drive with the sway bar connected.  A rear sway bar is not needed.

Thank you for the info.  I'm running 225lbs in the rear and 185lbs in the front. Another good match:)

I agree with your assessment of the handling.  I haven't installed a front sway bar yet, but plan to do so.