In Myrtle Beach - Black 1996 LT4 with only 1320 miles - 6 speed https://myrtlebeach.craigslist.org/cto/6118179957.html Image Unavailable, Please Login Image Unavailable, Please Login
All true but even the stiffest front spring available rate is 20% softer and the rear is 40% softer than the earlier Z07 cars and in the base cars the front wheels are narrower. Add to that the fact that the LT4 has less low end grunt and it all adds up to less of a sporting ride. No LT4 ever placed in the top 10 at the SCCA solo nationals when the C4 was the winning car in super stock in those years. That should tell you something. Part of the problem was the GS had bigger rear tires and they never got the car as well balanced as the Z07 cars even though they had a bigger rear bar to try to get it right, it just didn't work. The J55 big brakes that were part of the earlier Z07 package were standard on all the 95 and 96 cars, but the base suspension is so flaccid with 40% lower spring rates in the front and less than half of the Z07 spring rates in the back that you'd have to go thru the entire suspension to make a car that was anything more than a boulevard cruiser... And yes the Z07 cars are a lot harder to find, but if you're going to go for a C4 that's the best ride of the bunch from an enthusiasts standpoint. If you want an LT4 you need to go thru the suspension to make it handle like the earlier cars. The LT4 GS isn't as bad as a base car, but it's not as sharp as the Z07 and I've driven lots of both. With older Corvettes you have to be a bit careful in how the car was spec'd out. There was a huge option list and there we a lot of ways to build the car of your dreams. If the car was built for the country club set it was basically a mushy sedan with a sexy body. The last two years with the skinny front wheels and tires were even worse. Great for pulling up to the valet parking and unloading your golf clubs, but on a winding road you'd best just slow down and enjoy the scenery. With the stiff suspension, properly set up and aligned and with a good set of serious tires, you have a canyon carver of the first order, and there's a world of difference between the two.
Well you make the case for autocrossing only. For driving cross country, taking trips or going down a drag strip a couple of times then the LT4 all the way. Heck if I was looking for a cheap track car I would not even touch the C4 and move up to the C5Z for little additional outlay. But now we have gotten off track about what this tread started out as. Back to the 80's. To stay within the confines for 80-89 then the ZR1 and LT4 do not fit anyway. I think the Z07 came in the 90's too so it should be out if I am correct.
Enough time passed that in perspective, your 90's car is basically an 80's car with an AIRBAG. Everything up until 2006 is based on the 90's car. We're reaching a point where there's two types of vehicles, ones that don't upload your speed/GPS coordinates to the CLOUD versus cars that deliver streaming video of you behind the wheel to your insurance company. With a 1996 model, you can drive across the country and as long as you don't use a debit card to pay for gas, no one can track your route.
Saleen fox body 88/89 was my favorite and iroc 5.7 t tops when I was in my teens ended up recently restoring a 88 iroc 5.7 t top and a 88 Saleen both fun cars
this is one of my favorites - have had it for a while now and its technically a 93 but it belongs to the 80s Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
just looked at these on ebay - asking prices in the 30s. mine has 8k miles and I bought it on 2010 for 8500 bucks!
Looking good! I remember those fox bodies well. Had a buddy who picked up a then new 87 LX with the 5.0L and 5sp. What a blast that thing was. Remember when those last of breed 93 Cobras came out too. Unfortunately they were up against the new f-body with the LT1.
Sharp one! 107 R's for '93? So there are a few out there, but rare by current "Limited Production" standards.
Solofast, what would be your top three C4 Vettes in order of performance? 1 2 3 And, your dream Frankenstein C4? Maybe a certain year with suspension or chassis parts from other years bolted on? For instance, a 383 LT4 with wheels and suspension from an earlier car?
Number one has to be the ZR1, the 4 cam motor is so strong and sweet. Number two is the 93-95 Z06, it's the best handling of all of them, and it's not that much slower. Number 3 is probably the Grand Sport. The L98 Z51 is has huge grip, but the GS probably gets the nod because it's motor is so much stronger The Z07 or 89 Z51 are best set up cars from the factory and there isn't much you can do to improve on that. The C4 has a problem in that the rear roll center is too high if you try to increase either rear roll stiffness or rear spring rate the car will jack up like an old VW. The 84 Z51 had that problem, you would feel the rear jack up a bit, step over and then set back down. The 91 Z51 made the mistake of putting the ZR1 rear bar with the higher rate rear spring and it was horrible, thankfully that was a one year mistake. When you look at the spring rates for the big rear tire cars, they dropped the spring rates to allow them to use a bit bigger rear bar. The very early C4's (before 88) had better front suspension geometry in that the front kingpin angle is lower. When the went to zero scrub the kingpin angle was high and at higher steering angles you lost front grip. The most successful autocross cars were the earlier cars until the LT1 came along and gave the later cars a big power advantage. At about that time the 17 inch tires got better and we got parity with the earlier cars on autocross courses. The LT1 cars were superior as a track day car from the get go, 50 hp is tough to beat. The biggest thing that a C4 needs is more power and less weight up front provided you get the suspension parts off of a Z51/Z07 car. The car really wakes up when lighten the front end. Probably not worth it, but if you put in an LS motor with 450 hp and worked to take 100 pounds off the front end it would be the ultimate C4. Oh yea, and add the convertible frame braces (used on all the later cars) that helps the chassis stiffness. A 383 is a good way to go to, but to really ring the bell you need to get some weight off the front end. We built a C4 for SCCA Street Prepared autocross and the rules allowed us to update and backdate to build the fastest thing we could with all the parts in the parts bins from various years. We started with an 84 chassis (better front end geometry for racing) with a blueprinted LT4 running 315 Hoosiers all the way around with a 96 rear suspension.. Took out the A/C to lighten it and used the quick steering rack that was available some years. Car was about as good a C4 could get as a track day and autocross car, 400 dyno'd hp and every day driveability. Fun car all day long, but in the end and after all that work it cut lap times on the track and on autocross courses that were identical to a well set up stock C5 Z06... Which is to say that the C4 was a great car in its day, but time marches on. The C4 was designed really in the late 70's and early 80's, and finally got into production in 84. The fact that the car was produced for 12 years and was at the top of it's game until almost the end of the production run. But when you compare it to the C5Z you realize that the C5 is superior in every measure and it's time to move on.
I had a z07 and the motor was pretty weak. The solution was a custom built 383 which put out 440hp and 460 ftlbs. Went 183 mpoh in that car. At speed it was stable and contollable, unlike my then countach which wnated to fly and was so light in the front end at 160ish that you had to coun ter steer to go straight. one thing about he vette above 140 or so you could look in the rear view mrror and see that rear galls hatch shaking and jiggling around on its big rubber seal. Somewhere around 155 the seal woudl loose its grip and there would be a huge whooshign sound and suction as thougha rear window was opened, cabin air pressure notably dropped. I once read thata vette was a loose collection of prats traveling in the same direction. While the vetet was predictable stable and as safe as a period car could be at speed, probably better than the others, it also never felt all of one piece. After 30k miles it felt like used tupperware, everything worked but it was just feeling worn. Its always been clear to me that the vette engineers know how to do things right, they just lack resources. The Zr1 motor was fanrastic in the few I rode in, seems too few vette buyers then drove with enough gusto to make it worthwhile. Thats somehting that has changed, we see lots of vettes at the track, and people seem pretty prepared to pay 100k+ for a vette now.
Correct, 107 1993R's and 4993 "regular" 1993 cobras, for a total of 5100. The last 7 of the Rs were supposed to be regular cobras but a dealer in Colorado sued Ford to fulfill his R orders so they took the last seven and made them Rs and he dropped the suit.
Here is my 1986 Shelby GLHS "Goes Like Hell, S'more" Turbo. They only made 500 of them and they were all black. Image Unavailable, Please Login
All good observations, the stock LT motor cars would do over 170 if you had enough room to run them out. One thing that I tried never to do was to take the roof out. Even though you could take them out it made the car a lot stiffer since it was bolted in in 4 places. If you took the roof out of a Z07/Z51 car it felt like you were sitting on a stiff axle and you would see and feel the cowl moving and twisting in front of you. In some years there were door pins that made the doors part of the chassis and that helped, but the car was horribly flexible with the roof out. The problem with that is that the dash and a lot of the plastic in the car creaked and groaned if you drove it with the roof out for any amount of time because of all the flexing. If you never took it off the interior pieces didn't get flexed as much and the car was a lot tighter and more quiet for a lot longer period. While the car was a lot more flexible with the roof out what was interesting is that on an autocross course taking the roof out didn't make any difference in lap times. To find that out GM set up a course on "black lake" and ran one car back to back over about 50 runs and actually went thru a set of sticky tires and the results were that the car turned the same times and had the same grip levels (this was back when telemetry setups were for auto companies only) with the roof in and out... Some folks ran autocross with the roofs in, others with the roof out, but since I was driving my car to events and towing race tires I kept the roof in.
Wow, what a great job! What did you do at GM exactly? You sure know your C4s! I still have my LPE 415 stroker ZR-1.....won the Texas Mile street class back in the day going 185 mph, which is still faster than any stock new Vette, not to mention that it's still competitive for an n/a car even 20 years later. Those C4's had the aero if you added enough power, and the LT5 is intoxicating when it's uncorked! 1990 Corvette ZR-1 - Custom 610HP C4 Corvette - Vette Magazine
I worked at the Allison division on gas turbines, it was an eighth level job and that got you on the PEP plan. I was autocrossing at the top rung on a national level (SCCA and NCCC), and had tire support form Goodyear and later BFG and was good friends with the suspension guys at Milford (and still am today sad to say one of my Det region friends just passed away). Since I was running in the stock class while we were part of GM over the 12 years I ran C4's we got to know the suspension intimately. We were all fast because we did extensive testing. One of the guys from Milford would rent the Kinrosss airport pad and we would go up there twice a year (spring and fall) and test for three or four days, go thru several sets of tires and beat ourselves to death. Kinross had a mil spec concrete surface similar to the surface at Salina and later Topeka so testing on that surface was an advantage going to the national championship. There were usually 5 or 6 C4's at each of these sessions and we all learned things and shared information (most but not usually all, hey we were competing after all), and the extensive testing made us all faster. We had timing that would do splits and had g loggers even back then and knew what worked and where, and where we needed to improve as drivers and with the cars... It was a lot of work, but we all had a lot of success. It totally proved the axiom, the harder we worked the luckier we got.
For cars built after 1988, the J55 (stock big brakes) are fine for anything short of real serious track duty. Remember these brakes have 13 inch disks and nice big calipers, and while you can put huge brakes on anything it's more for bling than stopping power. One of the reasons they had to go to 17 inch wheels was so they had room for these brakes. Even with slicks on the car and serious pads, the pedal pressures and balance and modulation are very nice with those brakes. You can trail brake a J55 car on Hoosiers very nicely right up to where the ABS system is tickling your toes... It isn't the heat capacity of the brakes, it's how to keep them cool enough if you're doing serious track work. You can spot a J55 car with one quick glance. If the disks fill the front wheels almost totally, it's a big brake car. If there's a gap around the brake disk it's a 11.5 inch brake car. For street or autocross duty even the small brakes aren't bad, but they're not in the same league as the J55's... The J55 brakes don't fit the 16 inch tire cars, they came along when the suspension was upgraded to the 17 inch wheels. And nothing fits an 87. 1987 was a bastard one year only for Corvette front suspensions. Almost nothing fits it, shocks brakes, nothing. That, and the miserable 4+3 are both reasons to stay away from an 87..... For earlier cars you have to go aftermarket and that means changing to bigger wheels too. There were some kits available to upgrade the earlier cars to fit the J55 brakes, but I don't know if they are still available or not. Obviously you'll need 17 inch wheels or bigger to fit those brakes to an earlier car. If you're going to track the car and you don't have a power upgrade you can get by with J55 brakes if you add spindle ducts and cooling to the front of the car, and a good set of high performance pads. They work fine, for light track work, but after a while the calipers will warp and you'll get pad taper. But if you're on slicks or Hoosiers or have a bigger motor you need to go to aftermarket brakes and that's a whole nother question. If you're tracking the car with more power and grip you'll absolutely need brake ducting as the first mod you ever do. If you're at all thinking of tracking a Corvette get on the Corvette Forum and go to the Autocross and road racing page of the general forum. There is a huge amount of info about tracking Vettes there. Most folks don't bother tracking C4's since the C5's are so much faster and are much better track day cars. There's a few C4's still out there tracking, but these cars are so old now that it's less expensive to track a newer car. 89 and later cars had a 4 channel abs system that was a big improvement over the 3 channel system on earlier cars. The 4 channel system worked each wheel independently and even if you were getting a bit of ABS action it didn't mess the car up.
thx... i have a 90 zr1. i guess i have gotten used to the braking a newer cars i have it on my list to upgrade to some better pads. i tracked it once at RA but took it supper easy on the brakes. there is some little proportion valve spring that DRM sells for the master cylinder ?
I wasn't really thinking ZR1 in my response since there aren't that many of them around. With a ZR1 you need to take it easy on the brakes if you don't have extra cooling on the track. Really, with any Corvette, it isn't the brakes themselves that are the issue with tracking the car, it's getting them cooling air. These cars were designed to keep as much air out from under the car as possible (better drag and lift) and the designers were successful. But the brakes are cooled by that air that gets sucked out the wheel wells. Note that the wheels are designed to help pull air from the brakes and if you have aftermarket wheels that can hurt brake cooling some too. The real issue is cooling and big heavy cars need more cooling. With a heavier car you're on the straight longer, and in that longer time you put more energy into the car, so you need to take more energy out when you want to slow down. If you go to aftermarket bigger brakes, it will just prolong the amount of time you can run before they overheat. The best approach is to add cooling ducts and spindle ducts and get the air to the center of the rotor so you can take more heat out of the rotors. I don't think I'd be wanting to bugger up a nice ZR1 to do track days, but if you want to do one and are careful and put on some better pads you can have fun with the car. Just don't expect it to do a full 20 minute session and have any brakes left if you don't have some cooling ducting. Your car has the same power as a C5 Z and a bit more weight, so you need more in the way of brakes than all the other stock C4's and even a C5 Z. Most folks tracking at C5 Z06 add cooling ducts and spindle ducts and serious pads, and if you were going to track a ZR1 C4 that is probably a requirement. Also remember these cars aren't new, and if some previous owner tracked the car he could easily have spread the front calipers. Look at your pads for taper and make sure they wearing true. If the brakes are in good repair, then if you want to do track days with the car you're going to need brake cooling. A serious set of pads will go a long way, but what happens if you upgrade to much more heat capable pads is you'll eventually overheat the calipers and they will spread and at that point most folks go to a serious set of aftermarket brakes. There are kits to add C5Z brakes to late C4's, but those brakes have the same problem as the J55's. If you get them too hot the calipers spread and you get poor braking and bad pad life. They're better than J55's but not as good as a serious set of track rotors and calipers. If you were going to do an upgrade there are aftermarket big brake kits that made for tracking and that is what I'd do if I wanted to do more than an occasional track day. I always found the ZR1 to be just a bit more ponderous than a Z07, but it was certainly faster. With the bigger rear tires and different weight distribution I can see where you might want to adjust the bias a bit. I just don't have as much seat time in ZR1's. For me the motor was the star of that car and rest was along for the ride. If I were thinking track days in a ZR1 I'd be looking at putting 315's all around or at least upgrading to 295's on the front to get some more front end grip and that would be a real ride. Wider front tires aren't as crisp, but you need more grip on the front of a ZR1 to compensate for the additional front weight. With the stock brakes and with the C5Z brakes some folks use titanium spacers behind the pads (titanium is a poor conductor of heat) and stainless pistons (better life and less heat transfer) to keep the caliper temps down and keep the fluid from boiling, as well as putting off the dreaded caliper spreading. Doing lots of little things can add up to a pretty big difference in performance. If you want to do an occasional track day you could go with spacers, stainless pistons and high performance pads and a really good fluid and that might get you some more time before you let the smoke out of the brakes (brakes are like electronics, they rely on smoke, once you let the some out they don't work anymore), but if you want to track the car you need cooling ducts and other mods. One last note about fluids. These cars are old and brake fluid goes bad with time. If you even think about a track day you need to change the brake fluid to a higher temp fluid that is fresh. Tracking these cars with old and not the best fluid is the fastest way I can think of to meet a tire wall.. Don't know if your car has ASR or not, but changing fluid also entails properly bleeding the ABS system. If you google ZR1 brake bleeding there's several pages with how to do that on the Corvette forum. It's often said that 90% of track prep is just good maintenance, and that's probably still true. Don't know about the Rippe spring, but Doug is a good source and if he says it works it probably does.
thx i had all the fluids swapped out after i bought it from the old man along with some hi test motul brake fluid. it's adventure @ RA was likely its first and last as i doubt the 70+ old man i bought it from ever tracked it let alone drove it hard.... i'll try swapping pads to see if it give me the feel i am looking for... now if i had bought one of those c4 challenge cars at the BJackson auction that went for $20k.....
Those were neat cars... Stiffer than all getout but really neat.. I used to have a set of Dymags that was a spare set off of one of those cars and I used them for autocross. Stock width, but out of the box they had 1/4 inch more offset and were really light. I had Hoosiers on them and was changing to my race tires and asked one of my competitors to "hand me that tire will ya"... He went to lift it up and almost hit himself in the face with it, it was so light...
