NBM LS1 M6

I'm getting ready to take the plunge, and purchase my first Vette. I don't think it will be for at least a couple more months. My first choices are going to be an '89 Z51 M6 Coupe or the same thing in '96 LT4 trim. The purpose is going to be for an autox car. :eek:

I need/want to know, however, if there are any C4 years '85-'96 that the Z51 option was not offered. Also, are there any C4 years (other than '84) that I might want to avoid. The two years above seem to be the best years for a C4 autox car, although I understand '86 was good (but the pre-'88 C4s came with 16" wheels, and that is a distinct disadvantage for tire and traction choices).

BTW, I'm spoiled with a '98 Camaro Z28 LS1 autox car with an almost completely aftermarket suspension. The thought of buying anything less than a '96 LT4 Vette creates the concern that it would feel as powerful in stock trim as my Z28. :(


[Modified by NBM LS1 M6, 11:55 PM 7/29/2002]

The Gooch

Seems to be more misconception about the '84 Z51.
The '84 Z51 and the new Z06 are the only vettes made that can take a 1g turn. The '84 was built to be an autox car. The suspension was designed after the formula 1 race cars.
I can vouch personally from racing my car, that it will out handle any car in stock form, and I have had ample opportunity to proof this.

The Dingo

This may be of some use: http://www.zr1.net/ZR1_suspension.html

Suspension specifics for every year and model C4 - if autocross is your purpose for buying this car - I'd buy a 89 or 90 Z51 car.

NBM LS1 M6

When I posted my original comment mentioning the '84 C4, I didn't have the handling characteristics of the Z51 version of the car in mind. It was the engine and fuel injection system that motivated my comment. Someone, who is a member of the Corvette Museum Hall of Fame, called the '84 C4 "the worst Corvette ever made." He told me that in person. I'll ask him about the handling characteristics of the car when I see him next week. In the meantime, I have no reason to question your statements about the handling characteristics of the '84 C4 Z51. I might have to start including the '84 C4 in my daily Internet searches. :D:D

Bob

CowboyNVette

I have read where the 84 is the best for autoxing if that is your only purpose then I would try to find an 84. :smash:

NBM LS1 M6

Thanks!!! I've added that URL to my bookmarks.

vader86

For purely AutoX purposes, the 84 will probably run complete circles around my 86 Z51 and any 89 Z51 or 96. However, my understanding from what ive read on here all this time, is that the 89 is the second best handling car to the 84's. 84's dont have the power of 89 or the LT4, but could still win in a high speed event too.

The spring rate is so stiff that youll lose the fillings in your teeth.

Road racing, i would go with the LT4. It can beat the stock 98 LS1 in a straight line.

The Dingo

Just curious - not looking to get into a heated or exhaustive debate on the subject but asuming a marble smooth & flat surface - why wouldn't an 89-90 Z51 outhandle an 84? The suspension setup is even more biased towards outright grip on smooth surfaces in the 89-90 than on the 84's - assuming no great difference in weight or torque to the 84's advantage I am wondering if the 84's ARE quicker on a smooth track surface or if that is a misconception because of the noteriety 84's have for having a stiff ride because they were the first year to have such a hard setup.

Check the chart - 84's don't have the hardest C4 suspension.

Going with an 89 or later car also gives you 13" front brakes.

Some say 84 suspensions are terrible but you have to put that in context - is that opinion based on real world daily driving comfort, outright handling, or something else? It all depends on what you are looking for your car to excel in in my opinion.

NBM LS1 M6

Okay. . . taking it by the numbers. ;)

All C5s run in stock SS class in SCCA Solo2 events. All C4s run in stock AS class in SCCA Solo2 events.

The Z06 dominates SS class in Solo2. The main competition for the Z06, if there is any real competition right now, is not necessarily the C5 Z51 Coupe. Any serious Solo2er buys a Z06 not just a C5 Z51 Coupe. As beautiful and awesome as a C5 Z51 Coupe might be, it is still a weak step sister to the Z06 in SCCA Solo2 events. One will see a smattering of Porsche Boxter S cars, Mazda RX-7s, and BMW M3s in SS, but they are the distinct minority.

I just did a scan of every finisher in the SCCA Solo2 National Tour and Pro Solo2 National Tour events in A Stock thus far this year. There were no '84 C4s listed in the finishers a fortiori the placers.

Here is the deal. . . The '84 Z51 Coupe might be a 1g handling car, but that is not the only factor in Solo2. It might hold its own on a postage stamp 30 second course, but on the typical Solo2 course power is a big factor. The power of the '84 C4 with cross fire injection is seriously dated. Although they run in an entirely different class, there are a lot of sub-compacts such as the Nissan Sentra SE-R, the Dodge Neon ACR, and the Mazda Protege/Ford Escort GT that will walk all over an '84 Z51 C4 on a typical SCCA Nationals style Solo2 course.

When one looks at the finishers in AS in this year's SCCA Solo2 National Tour and Pro Solo2 National Tour events, the class is dominated by three years of the C4, to wit, the '89 Z51, the '93 Z07, and the '96 LT4.

Keep in mind that these cars are all most likely Z51 models or models converted to Z51 specs for that year car. In SCCA stock autox class, one can convert a non-Z51 C4 to Z51 specs, but the car must be entirely converted, and that conversion must meet the specs for that particular year. There can be no mix and match of stock parts and options. For example, one cannot convert an '87 C4 to '89 Z51 specs.

The truth of the matter remains that I'm tempted to buy a nice low mileage '96 LT4 C4 just for the overall pleasure and power of the car, and modify it down the line to some competitive Solo2 specs, in some Stock, Street Prepared, or Street Modified (SM2) class just for the all around fun. I have to keep reminding myself that, at age 55 on a limited budget and time availability away from my job, I will most likely not be winning any Solo2 National Championships in the near future. I do, however, have a line on at least three nice '89 Z51 FX3 Coupes that are/will soon be for sale, including one that has won three Solo2 National Championships in SSL with a real driver behind the wheel. :D:D

Meanwhile, I have this nice '98 Z28 that only a fool would sell or trade. The modifications and the TLC I have put into the car over the past four years are just too awesome and cost ineffective to justify a trade. This car breathes down the neck of a lot of late model C4s, C5s, and even Z06s on an autox course. :D:D

vettackular

I have a '84 Z51 and it is AWESOME! For autocrossing it would be great for cornering. As far as power goes it is lacking for sure. So why not buy yourself a decent '84 Z51 for $5000 and put the rest of the money you would have spent on the '89 and beef up the engine, that you way you have the awesome turning with the power to autox all day long.

Just my 2 cents, good luck in whatever you get. :)

Scoob

Nope. The steering and front end geometry is much different in '89 (zero-scrub radius front suspension (introduced in '88) ) than '84.

In the autox world the '89 Z51 is the one to have.

91-Z07Coupe

How do the Z07 cars compare to the Z51 cars?

The Gooch

But how many 84's are actually entered.? Yes the 84 lacks the power on the straight, but I usuaally gain advantage on the twisties. It's not exageration when you hear about the stock trim of the 84 Z-51. The car handles like it is a slot car on rails. I had a friend of mine trailing me on the street running a T/A. Granted, he would of took me on the top end, but I hook him into the twisties on an overpass that had 2 turns. He lost his tail! Actually almost spun. I was running 125 mph around the turns with no feel of slipping. My friend has a 911. He was behind me and told me that my car didn't even lean :eek: Hence the ride that will knock your fillins out :D
Also, how many people making comments have actually driven an '84 or even auotcrossed :seeya Autocross is not about speed, but handling and driver capability.


[Modified by The Gooch, 6:13 PM 7/30/2002]

vader86

Z07 is a combination of Z51 and another code, FE1? FX3 shocks? But basically it was the substitute for Z51 in those years.


[Modified by vader86, 11:25 AM 8/1/2002]

NBM LS1 M6

I'm getting excited. I may have found the '89 Z51 I have been hoping to obtain. I'll know more in a few days or so. :D:D:D

JasonL

The lack of '84s placing well at large events speaks volumes. I guess some people hate to admit it but power *does* matter in autox (maybe I should phrase it, lack of power is a detriment). The C4 is not a little Honda that only needs 150hp to scoot around, it is a big fat turd that weighs 3200lbs.

Just keep in mind that '89 and '90 Z51s that had FX3 reverted back to the base springs (and bars?). I don't know if the cars you have in mind reverted to Z51 non-FX3 specs or what, but something to think about. Check out the "Corvette Black Book" for more details.

ericcer

My last car was a 98 M6 T/A LS1 and I found the power of the LT4 satifactory. I too was concerned about going from a LS1 to anything less than an LT4. With an 84 the power be a lot less.

Go with a LT4 and you can beef up the suspension. That is easy.

MrNuke

Just to add my 2cents.. :D
84 Z51's handled like on rails, but lacked the pulling power getting out of turns, then the '85 Z51's got the TPI and made up for it nicely. They only softened the suspension a minute percentage , lot less than the following years. I think an 84 or 85 Z51 and put a few grand into new tires/17" wheels and some performance mods, and you got a great autox car. BUT if you can afford, I'd say get the newest you can get and modify fromthere on. You can make almost any car handle better, doesnt matter what year, if you spend enough on it.

NBM LS1 M6

Well. . . everything else being equal that sounds like a no-brainer. There is just one problem. No modifications are allowed in SCCA Solo2 Stock Classes except shocks and the front sway bar. Real power modifications put the car in the same class with Formula cars that run on tube frames. For that matter, some of the most minute modifications do the same thing.

SonnyinVA

ok here it is!! right off the chart!!
http://vettenet.org/susp_chart.html

your best bet is the 90-91 Z51/Z07 package, with the Z51/Z07 package you get all the extra goodies... they all have the same bigger brakes, trans cooler, auxiliary fan, quick ratio steering, etc...
the best is not the 88 and 89, they actually have a smaller diameter rear swaybar (24 solid) than the 90-91's (26 solid)... everything else is identical tho...

the 84's sway bars are actually smaller at 25 solid in the front and 23 solid in the rear compared to a 90-91 with 30 solid front and 26 solid rear.
the 84's rear spring has the highest rate out of all the c4's at 87.5 but the 88-91's are a close second with 57.2, but 88-91 have a higher rate front spring @ 115.5 than the 84 which has 102.0.

to summarize, 90 and 91 Z51/Z07 have the BEST suspension setups...
AND all the extra goodies...
91 is my pick because you can get the new body style, followed by the 90, which is exactly the same but with the old front and rear fascias. 90 and 91 also have no MAF to deal with... they have speed density system... L-98 has great torque for getting you out of the corners and opening up the exhaust really gives them a kick in the pants... they'll fly in the straights too... just gotta shift sooner than the LT1/LT4.
the 96 LT-4 has great power but the suspension on the 96 sucks even in its' best form...
just my $.02 worth...


[Modified by SonnyinVA, 6:21 AM 8/1/2002]