by Bart A. Lane #W1379
When I bought my C5 it was not under the best circumstances. I was far from home and my 100k plus mileaged C4 had developed a horrendous shimmy that no shop could fix or give me a definite diagnosis. There was 10-12,000 more miles on this drive and over a month to go. I had enough and wanted a new Corvette. I was pressured which is never good. Fortunately I was near a large C5 dealer in Joliet, IL which went by the name of Bill Jacobs. The main thing is that I wanted a color, I didnt want black, white, or silver. Red, green, or blue were all possibilities I would engage. The only color they had on the lot was a low mileage, GM buy back red coupe with auto and no performance oriented options. Im talking base axle ratio and base suspension and automatic transmission. Had I ordered I wouldnt have optioned one of these things. I wish the original owner would have spent the money for the side trim, cargo nets and covers, CD-player, and floor mats on something that made the car more like a Corvette and less like a Lexus. No sweat though, I have a set of tools, I could make it better.
Z51, remember that code and dont order a C5 without it. All benefits and no negatives. Ride is still fantastic and it handles like a totally different car, a better car, a racing car. The parts difference between the base and Z51 car involves shocks, springs, sway bars, and a power steering cooler. My search began and my credit card found its usual place on my keyboard.
I decided to bypass the springs. From what I understand they dont play that big a role in the upgrade and are also the most expensive. Sway bar diameters and shock valving is whats going to make a difference. I got lucky one evening. Not being able to sleep I tuned into alt.autos.corvettes around 3:00 AM for some reading. Some new messages came up and one had the subject line, "Selling new Z51 sway bars F&R $100" He had just posted and since he was in Florida and I was in Seattle I figured he was getting ready for work. My e-mail was answered immediately and he said that the roads to the beaches were too full of potholes and the Z51 bars made an already unpleasant drive even worse. I shot off a check that morning and had my sway bars ten days later.
The four shocks and power steering cooler I bought from Mallett Cars. (http://www.mallettcars.com ) Any of the aftermarket tuners that get cars right from Chevy to alter are great places to buy take offs which means they removed them from a new car to add their own components. I bought from Mallett simply because they were the first I called and Matt had always answered my e-mails quickly and thoroughly. I also picked up a brand new power steering cooler here as well.
Like brakes, putting in suspension pieces is simply a matter of returning nuts and bolts where you took them off. Quick Tip: If you are having a hard time getting the sway bar end nuts loose because the stud keeps spinning bear in mind that there is a Torx fitting on the bolt to hold it still. Made life a lot easier once I saw this!! Something that has always ticked me off about GM is there persistence to use single stud shocks with a top bolt that spins the whole shock shaft when you try to loosen it or tighten it. Do not grab the chrome shock plunger with a pair of pliers or the shock will be ruined instantly. Instead, place a 6mm wrench on the square tip of the shock stud. It sucks but it is all you have.
The power steering cooler was very easy to put in and used existing mounting holes that the regular fluid line used before the swap. Make sure you use GM dedicated fluid for power steering, ATF will not work. This took about 15 minutes from start to finish. Too bad I sat an entire afternoon aside for it and was bored the rest of the day.
I cant praise the Z51 suspension enough. I had both in identical cars and there is no difference to me in ride quality but it handles much better. Better turn it, tons more neutral, and more level cornering. How the C5 guys did this is beyond my ability to comprehend. If you have a choice get the Z51 suspension, I cant see why you wouldnt.
Since that is not the longest tech article in the world I would also like to discuss some cooling upgrades that were performed. Any engine in the world will perform better if it is cooler and thats just the laws of physics. Anything you can do to lower operating temps will yield performance gains and the LS1 is no exception. Fortunately there is much that can be done with the stock C5 cooling system to bring that reading way down. The cooling system modifications performed on my car are as follows; Fluidyne aluminum radiator purchased from Mallett, 179 degree thermostat, Hypertech programmer to lower fan temp activation, Redline Water Wetter, and a 25% concentration of DexCool and distilled H20. On the freeway my coolant is no warmer than bath water and this is no exaggeration.
Due to the amount of aluminum in the LS1 powerplant it is a very good idea to use distilled water to keep unwanted minerals out of the system. You also want to use as little coolant in the mix as you can because Redline says that the Water Wetter is most effective in higher water content. Water Wetter is a fluid that bonds to the surfaces inside your cooling cavities and makes great contact between metal and water. This moves more heat out of the engine and into the water where it can be cooled. In my area (Seattle) I feel very comfortable with a 25% mix of DexCool.
The thermostat is very straightforward to put in. Takes all of five minutes and is very accessible. A lower temperature t-stat will simply do as the name implies; open up and let the hot water out of the engine at a lower temperature than the stock one will. This results in a cooler engine. It is a good idea to use this in conjunction with the Hypertech Power Programmer which can turn the fans on at a lower temperature. If you only do all of the above and leave out the expensive aluminum radiator your LS1 will run much cooler and thank you for it. A cool motor is a happy motor. The only concern you might have is if you use cheap oil (non-synthetic) and don't change it very often because cool oil will not burn off the contaminants like hot oil will. But no Vette driver would do either of those things, RIGHT?
OK, now on to the fun stuff . A big, fat, beautiful aluminum radiator manufactured by Fluidyne and sold by Mallett Cars to me. This is one impressive unit, trust me. First off, the whole thing is aluminum; no plastic tanks, no flimsy fins, no breakable nipples, etc. It is just a strong looking piece that reeks of quality and longevity. The core is over three times as thick as the skinny stock radiator. If you could see your stock radiator in your hands I think you would want to change it because there just isnt much to it. This is a direct bolt in cooler and no modifications are necessary. I should take that back, a few changes are in order but they dont amount to much.
Very important common sense tip here folks; Dont disconnect an air conditioning line going to the condenser in order to get it out of the way. It is not cheap to get it filled again and somebody from Greenpeace may shoot you in your sleep because even the new R134 is not ozone friendly. Careful not to poke a screwdriver through anything either. The only modification I had to make was in the way the fans were mounted. On the stock radiator the whole fan shroud just rested in four slide clips that were molded into the plastic radiator tanks. The Fluidyne radiator was built to accept small bolts at these locations so I merely had to drill four holes in the fan shroud and pass some bolt/washer combos through them. Take a look at the pictures and you will see what I mean.
OK, if you have been following along the whole time you will see that I have built up my brakes to a level that can repeatedly stop a powerful car quickly. You will see that I made an already excellent suspension even better by upgrading to the best Chevy had to offer. And you will see that I have created a very powerful cooling system that will deal with any extra heat a modified engine might throw at it. We are covering all of our bases before we begin making big power. This is the really the best way to go about it, not to mention the safest.
If you own a six speed you can skip my next installment. With the exception of upgrading the clutch there is nothing that has to be done to this drive line combination. The automatic, on the other hand, leaves much room for improvement. Unfortunately for my wallet, my car has the auto shifter. No worry because next issue I am going to talk about some major and expensive changes that my car underwent. A 2900-rpm stall speed converter, a set of 3.42 gears in the differential, a high quality shift kit, and Redline synthetic fluids. These changes, while not only help to prepare for the power increases we will make, also increase the performance of a car considerably in their own right. Actually, one of the biggest performance bangs for the buck you can make is to add a stall converter. All of that is next week and I dont want to reveal too much now. And then ..we pop the hood and get to work on building one very fast Corvette. Keep tuned in.
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