[Augusto]

Hi, everybody. I'm really excited to go for an all out track car project.

I'm really puzzled at this dilemma: could a 98 Z28 be modded to match or surpass the handling of a C4 with Z51 like susp (Crossmember and camber brace mods)?

I may be able to trade my 98 LS1 Z28 for an auto '95 C4 (and like 3K of cash, and I would swap a ZF6 and mod susp). C4s are not so cheap to get in my country (as opposed to fbodies), let alone C5s. I was just about to swap a T56 (with relocation crossmember, Z06 clutch, etc) on the Z. Before I just do either of it, I want to make sure to know if I can achieve handling capabilities of a Z51 C4 or close through modding (shocks, tires, rims, sfc, kmember, a-arms, torque arm, lcas, panhard, strano swaybars, rollbar, a little diet, etc). Guys please be honest.

I've seen biased opinions on the C4 side by people who do not really focus on track improvement (and take stock form as a reference) so I thought this would be the right place to ask.

I want to make sure to invest time and effort on the car with better handling potential (modded) on the following couple of years. (Ultimate purpose: Road Racing and a little of AutoX).

[00 Trans Ram]

Does anyone have any other head-to-head results?Here's why I ask. Given equal prep, an LS will make more power than any engine the C4 came with (except a few of the expensive ones). They will weigh just about the same (2800lbs). They have equal rubber. They have same weight distribution (53/47 or better) and cross weights (49 or better). So, let's assume that the C4 IRS is actually better. Is a slightly better suspension a bigger advantage than 20 or more hp?I'm talking about RR, since the original guy said RR with occasional autox.

[Mojave]

Does anyone have any other head-to-head results?Here's why I ask. Given equal prep, an LS will make more power than any engine the C4 came with (except a few of the expensive ones). They will weigh just about the same (2800lbs). They have equal rubber. They have same weight distribution (53/47 or better) and cross weights (49 or better). So, let's assume that the C4 IRS is actually better. Is a slightly better suspension a bigger advantage than 20 or more hp?I'm talking about RR, since the original guy said RR with occasional autox.

I think the C4 will come up lighter with better distribution, as the engine sits a bit futher back relative to the front wheels, and the driver sits closer to the rear wheels. Also, the C4 front geometery is better with less unsprung weight (aluminum a-arms and spindles), more avaliable caster and (I think) less scrub. The biggest advantage of the C4 IRS is no braking wheel hop, but there is also less unsprung weight, and the easily adjustable camber and toe (yes, you can camber and toe a solid axle, but it's much easier to adjust with IRS). LSx will definitely make more power, but LSx swap parts are out there, which at the very least is 75 lbs more off of the nose.

All that said, another comparision point is the NASA TT classing structure:
Chevrolet Corvette C4 ('85-'91) TTD**
Chevrolet Corvette C4 ('92-'96) (LT1) TTC*
Chevrolet Corvette C4 (LT4 option) (330 hp) TTC**

Chevrolet Camaro 3.1L TTG*
Chevrolet Camaro 3.4L TTG*
Chevrolet Camaro 3.8L TTF*
Chevrolet Camaro 5.0L carb (170 hp)('87) TTF**
Chevrolet Camaro SS ('98-'02) TTD**
Chevrolet Camaro SS ('96-'97) TTD*
Chevrolet Camaro Z28 ('98-'02) TTD*
Chevrolet Camaro Z28 (pre '98) TTE**

These are for totally stock cars (down to the shocks), but the fastest listed F-body is LS1 SS cars at TTD**. The TPI C4's are in the same class, with the LT1 a class up in TTC* and LT4's in TTC**.

For those unfamiliar with the NASA structure, TTA is the fastest, TTF the slowest. The * indicate the number of class points you start with at base, so a TTC** is faster than TTC* which is faster than TTC, all of which are faster than TTD**.

This post has been edited by Mojave: Jun 23 2009, 08:08 PM