s13 with Corvette C6 rear suspension and trans

[drmotorhead]

I am planning my next project car and would like to get input from anyone with constructive comments. There should be pictures at the end of this post. If you don’t see them, I will add them shortly.

Not counting a boring year after turning 16 and having a VW Beetle and then a Toyota Tercel, my first real car was a Datsun 260z that the previous owner had converted to a 350 chevy with a 700R4 trans using the JTR(Jaguars that Run) designs. It ran well, but it was a little fragile. Working on it was great fun and over several years I disassembled and reassembled the car more than once for various repairs and modifications. Since then I have owned and modified many cars, including a Buick Turbo-T, C6 Z51, C6 Z06, Corvette C5 Z51, a Supra, an NSX, and a 98 Camry CE V6 manual with the trd SC, headers and extra boost. I just sold my 2000 M5 that I enjoyed turning into a 450hp 3650lb ride.

I am ready to build a 240sx version of my first real sports car, the V8 260Z. This is the basic outline.

S13, early year, no sunroof, manual windows
Stock exterior other than steel flared fenders that follow the body line, similar to Chargespeed 30mm front w/o holes at the trailing edge and Chargespeed styled 50mm rears.
255 fronts tires, rears 285 – 315’s depending on what fits, normal camber, no wheel protruding beyond the tire.
Only in the front: BBK, coilovers, and 5 lug conversion(why only front? Keep reading.)
LS7 engine installed with Sikky kit, or, since DFI excites me way more than my ex-wife, possibly a C7 LT1 with AFM and VVT deleted and a cam.
Slightly wider front fender to accommodate a wider tire, approx. 255mm(normal camber, no wheel lip protrusion)
2” wider rear fenders to cover 285-305mm tires
Various weight saving measures: CF seats, a one speaker stereo, real CF hood/trunk or hatch, Braille li-ion battery, use aluminum or Cf where possible.
Complete rear suspension and manual transaxle from a C6 corvette

The last one is the clincher. Why do this? Weight distribution, technologically advanced and high performing rear suspension geometry, a nearly indestructible trans and LSD, great brakes. 2008 and up Z51 tr6060(or from a Z06) has upgrades from the T56 architecture. No need to add a BBK, new LSD, better half shafts and various suspension pieces to make the stock rear work well with 600hp.

The s14 has a weight distribution of approximate 55-45 front to rear. Great for drifting, not so great for putting down 600hp.

The s13 starts at 52-48 front to rear. Better than s14, but still nose heavy.
Moving the 100lb+ trans about 4ft to the rear is a big transfer, and the beefier TR6060 is a little heavier than the T56.

Changing from a 45lb lead acid mounted in the front to an 11lb Li-Ion battery in the rear will help. Real CF hood drops some weight on the front. There is the potential to get the front end weight to around 1250lbs, which means a conversion to a manual steering rack becomes possible. I have read a manual steering rack and losing the pump and hoses drops 30+ lbs.
The projected curb weight is 2750lbs with AC, a one speaker stereo, and a pair of CF shell seats, and no back seat(maybe a couple of lap belts and pillows in case I want to scare three passengers at the same time).

With all of this, the weight distribution changes to somewhere between 47-53 and 45-55, partly depending on body style and a few unknown factors.

The Nissan rear is fairly compact and made of steel. The C6 suspension is aluminum and similar in size. There are 3 issues with mounting a c5/c6 rear in any other car:
Different mounting locations for the cradle
The C6(and C5) upper control arms do not mount to the cradle, they bolt to the chassis,
Upper shock mount is not in same location

These problems are made much easier to solve with a somewhat new product: Corvette Interface Suspension Adapter by Dobbertin Performance. This is Rick Dobbertin’s company, who some of you may recognize from his pro-street creations or from his amazing Surface Orbiter.

This upper cradle adapter allows the whole rear assembly to be bolted to a back-half frame that has rails at the appropriate height. Get the rails in the right place, everything else flows around it.

I would like to get the traction control to work. This car will be street driven, and my Z06 was difficult to drive in the rain. I would not drive in the rain on purpose, but I am in west central Florida. If the engine control computer has the brains and the rear is set up for wheel speed sensors, and we can add sensors to the front hubs and wire it in, it should doable.

Since the rear is getting back-halfed, the spare tire well can go and the gas tank would have to be reconfigured. The back seats are already getting mostly eliminated. These changes can free up a lot of room for exhaust routing and mufflers.

Comments?