Ask DJ Race

Answers provided by Danny Kellermeyer. Danny Kellermeyer is a force to be reckoned with in the Corvette racing world. Danny and his team of Corvette drivers have dominated several Corvette club racing series. He has no plans to rest on his laurels after capturing the 2010 and 2011 Sports Car Club of America (SCCA) Great Lakes STO National Championships, as well as the Waterford Hills Road Racing (WHRRI) 2010 and 2011 STO championships. Send us a quick email with your name, location, and a short question.

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Congratulations to Danny Kellermeyer for setting new track records and making history as the first Corvette to win at NCM Motorsports Park! Read more in the July 2015 DJ Racing Excitement Newsletter...

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Q:

I'm lost what to put in my street-driven vette. It's the original motor 350/350 bored 30' over with 11.01 compression and original stock 202 heads. I would like to do an engine rebuild kit, but not the strokers. I also want to get it blueprinted and Dyno tested to make sure everything is perfect. AC, PW,and PB are all stock. I don't want to change the heads; the crankshaft was replaced back in 1986. I already have a newer manifold and carb. I need pistons, rings, cam, lifters, all bearing, main, rear, camshaft bearings, etc. Wanting more power if that's allowable, without doing major changes. What do you think would be a great kit? And what would you do?

– Kim Quintero

A:

Hi Kim, Sounds like you have a nice engine project ahead! If I remember correctly, the 350/350 was L46, a higher performance version of the base 350 cu in V8, 492 heads with 2.02"/1.60" valves, 11:1 compression ratio and produced 350 hp. It was a four bolt main block, forged crank and forged pistons. At this point in time, if a hod rod guy could get 1hp/cubic inch, they were good. Now the Corvette engineers did this for the consumer. So I would say “Don’t screw with a good thing”. Focus your rebuild on the good stuff. The forged pistons were TRW originally and are still a good replacement. Heavy for today’s weight, but your crank is balanced to that kind of weight. Hypereutectic would be second choice but stay with forged for a good fit and reliability. I use Clevite brand. The cam you have is a good design for road and performance. I’m sure your cam is worn, as all flat tappet cams become, so get a replacement. Most cam companies still service that same grind. Bottom line: it is hard to beat a good thing. That engine was smooth, had low end drivability and upper end performance. Heads flowed well and lower end held strong and tough. That was a well designed and well built engine.

(FOLLOWUP)

Thanks Danny, and you're right...I don't want to change much. I would like to put in a roller cam and lifters; what would you recommend as a kit? The rest will stay the same except if I need to replace the springs and pushrods. There is so much to choose from, it's mind-blowing. If you could give me your opinion on the retro roller kit, that would be great. Again thank you!

– Kim

A:

Kim, Thanks for your follow-up question on your engine rebuild. A roller camshaft can reduce the frictional load of an engine, taking less horsepower to turn and generally not wearing out as quickly. An added benefit is roller tappets do not require replacement when changing cams. Roller profiles can be more "aggressive" and accelerate the tappet more than a flat tappet profile. If a cam profile is more aggressive, it has more "area under the curve", which means it can make more power. Make sure the camshaft kit you get is for an early small block and not one for a hydraulic roller cam late (86 up) small block. Your original 350/350, 1969 Corvette engine flat tappet was 224/224 degrees duration @ .050 lift, so I would get something like this or slightly larger (approaching 230). Stay in the 112-114 lsa. This should give you a little more power and still have drivability. Here is the real concern: price. The roller cam and lifters will be $600-$800. Add pushrods, cam button and you are in the $800–$1000 range. A new flat tappet hydraulic cam and lifter will be $200–$300. The increase in power you want can be achieved with either cam, just depends on your budget. If you choose the flat tappet cam, make sure you apply cam lube (high in zinc and phosphorus) and use oil which is high in zinc and phosphorus. Oils today have eliminated these additives. You can also use a ZDDP oil additive to increase zinc and phosphorus levels. I still do that on all our race engines even though I run a roller camshaft. Hope this gives you a little more insight!

Q:

I just bought my first '05 convertible corvette and want to add two things: a classy looking wind restrictor and a pair of hoop roll bars behind the seats. Having searched the web, I have found several restrictors that I like, but few roll bars. Do you have any idea who produces those or do you know anyone who will custom build something like that? Also, do you think I will have room behind the seats for both the bars and the screen? If I cannot fit both restrictor and bars in my car, I was considering the chrome hoops that are mounted with a peel-and-stick method, but that kind of mounting seems a little suspect to me.

– Denny Brune

A:

Mr. Brune, Thanks for writing in! It sounds like your C6 is one of the most personalized convertibles I’ve ever heard of. I’ve seen a few roll bar hoops in C5 and C6 convertibles. I do know SR1, Racefab Inc, and Corvette Central all have one that goes to the bulkhead and attaches there. None incorporate both hoops with a windscreen, however. Personally, I like the one Corvette Central sells for its fit and intrusion into roof space. I remember seeing a Callaway that had a windscreen, but don’t remember if it had two hoops or just one. I’ve seen quite a few decklid mounted hoops that look good but are completely dress up items and, again, wouldn’t have a combined windscreen. I think you would have to go to a custom outfitter to get what you wanted unless you start with one of the 2” seat hoops and combine the two with a windscreen material. That's something one of the Corvette outfitters would have to do, and you are right, there isn’t a lot of room to do all of this on your car. Just remember, any of these are beauty enhancement as they are not intended to improve safety or roll over capabilities. All will have the footnote "does not constitute a roll bar" or "not intended for competition".

Q:

I bought my 2008 C6 Z51 with worn out Goodyear tires, then replaced them with BFGoodrich high performance tires at 14,000 miles. I ran 50 laps at Watkins Glen when the tires had over 30,000 miles. Never slipped or skidded, even on turn one, inches from losing her high on the red/yellow stripes. I am thinking of putting on Michelin Super Sport Run-Flats. I know this is a high performance tire but is there another you would suggest for me? I drive every day, winter and summer, and plan on a lot more track days.

– Howard Young

A:

Howard, Good Question on tires for a C6, and what better place to put a Corvette though its paces than at Watkins Glen? My favorite section is 5-6-7-8 (inner loop) combination. Nice and smooth on all the curbs, and allows the car to be an extension of you. I tend to look a lot at the tread design and ratings on the tires. The Uniform Tire Quality Grade (UTQG) is a comparison but doesn’t tell you all you need to know. If I’m looking at the right tires, both are Tread Wear of 300, Traction of AA and Temp of A. Actually, BFGs and Michelins are the two big players in the Corvette community, and are also my two choices. I see the Michelin Pilot as a little better, but the downfall is the price. It's about a third more than the BFG. Your tire life is better addressed with your alignment and proper track pressures. Find an extra set of wheels and use that set as your designated tire for your track days. The investment is more, but the payoff in the long run is worth it. It will keep your street tire edges sharp and that is what you want – good traction and the ability to cut water on wet roads. Start with manufacturer's recommended air pressure and then tailor it to fit your driving style. Alignment will be based on how much street driving you do, compared to your track time. Go to the high negative camber limit (for the Z06) even though you have a base car. If your driving style is a little aggressive, this gives you a good alignment for both street and light track. For more track time than just once or twice a year, go more aggressive on negative camber. Remember, keep your front toe to ZERO. Toe in or out will give you wear on the street. Sounds like you’re going to have fun during the 2015 season and that is what a Corvette is made to do.

Q:

What after-market parts will beef up performance and handling on a 2005 Corvette. Car was purchased from a dealer with $7,000. Owners were a bit afraid of it. My gain!

– Preston Woods

A:

Preston, Sounds like you got a great buy on your 2005 Corvette. The LS2 is a great engine to work with and a good start at its 400 horsepower and 400 lb.-ft. of torque. I'm going to assume your car is either higher mileage or a little rough (you usually don't find low mile and clean cars at that price). Do a few checks to make sure your engine is solid and running fine. You don't want to try to improve an engine with poor compression or with codes and misfire detection. A compression check and % cylinder leakage check will be a good start. Check out any trouble codes you may have. That is one of first things I do on the race cars even when I'm sure the engine is ok. Engine Improvements: Production engines like air and exhaust improvements. A good air cleaner system will allow air to come in and a good exhaust system will allow the air out for power improvements. Do your homework on the exhaust because you don't want to have the really high flow drone and noise if you are street driving it only and you don't want it closed to much if you're going to do all track stuff. The air cleaner and exhaust will give you initial improvements and has to be done if you want to go further with head and cam packages. The next step would be looking at head and cam packages. If you get to this point of power improvement, make sure you talk to your engine builder about what you're going to do with the car and which cam is best for your application. You don't want to get into a situation where your cam is a roadrace cam and you are street driving, or you're only going to be on the track and you have all low and midrange power. There are lots of great cams out there today, but do you homework to find the one best for you. Suspensions Improvements: I'm going to assume again you have checked the basic suspension out to make sure the bearings are good, the bushings in the a-arms are good and the tie rod ends and links are not loose. Springs and shocks make or break your handling on the car. An economical way would be to find someone who is upgrading their Z51 car to aftermarket springs and shocks. Z51 is a nice street package and if you want to autocross or do a day at the track, you can do it with a Z51. Or if you have suspension improvement money, step into a performance package which would include springs, bars, and shocks. These packages would limit some body roll and plant the tires to the ground. Of course you're going to have to reset your alignment and get the tires all pointing in the right direction. Brake Improvements: The one forgotten area most of the time is the brake package. Everyone wants to go fast but forgets about stopping. Make sure you have good rotors and a good pad. You don't need the high dollar big brake stuff, you just need good rotors and pads that will complement your needs. For street you will need a good quality street pad, Autocrossing or a track day you will need a better compound, and Roadracing or all Trackdays you will need a high temp and quality pad.

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