cobramatt

Chris, I would love to make my car flat bottomed. I would however approach it in a way that the underwing and diffuser actually worked and didn't resemble a flatbottomed car. I see loads of people who attach panels to the underside of a car, I see people buying diffusers all the time and not actually realizing that they are not doing anything but adding weight and drag to the car. The purpose of the diffuser is to allow the air that has been accelerated by the front splitter and undertray and due to that air being accelerated it creates a lower pressure area under the car and causes downforce to occur. The diffuser decelerates the air back to as close to the same speed that existed in front of the car originally. If a diffuser is designed in a wind tunnel or in a CMG virtual program it can then maximize the downforce and create less drag for the underwing. I point out that the undertray or flat bottom is simply much more than a large piece of plywood attached with clamps to the underside of my car. Thats fu@#ing stupid...........Could I redesign the underside of the car and create a functional flat bottomed underwing that had a functional diffuser. Yes I could. Do I have the time and money to undertake such a project, NO. I also contend that I am having a real problem with certain individuals that have all the advise of an armchair quarterback and no real practical sense of what is involved in actual application. I also wonder why does this data actually matter, when no one really has the need for such data. There are maybe a handful of people on the planet that actually would benefit from a functional tunneled undertray and diffuser for a 240. If you take that myself and only a few other individuals actually race these cars in a division that no build rules apply, anyone racing in any vintage division could not do anything with this data or application. At present, if I can get my car to the finish line in a 1 hr sprint race without something breaking I usually have a good chance at winning the race overall. That's really difficult to do and very satisfying when it happens, however if I were to redesign the underside of the car and do all this work and pay for it all, just so we can go to the windtunnel and a few curious people can see the data, well once again I see that as a waste of my time and money. An old saying is that "The juice is not worth the squeeze". If I had an unlimited amount of money and I really thought that this would make a difference worth the investment, I would probably do it. If I had an unlimited amount of money and could do whatever I wanted I probably would be racing at LeMans next week and not on Hybrid Z forum. If I were to spend money wisely and do the next step in the evolution of my car and do something I know would make it even more competitive is the suspension and brakes. I am presently working on fitting adjustable shocks and a MTI Racing big brake kit off of one of our Corvette race cars. That would be the wheel hubs and all. Just take the geometry that already works and I am familiar with and make it work under my Z car. The need to stop my car, to take it deeper into turns, to keep the brakes functional for longer periods of time, to make it stronger, smoother, more stable, better balanced, adjustable, etc.... You get the picture. I assure these items are 100% more important and relevant to my build than trying to attach plywood to the bottom of my car in a windtunnel. If anyone disagrees with me, I am no stranger to confrontation or controversy, I support your decision to take your car and your plywood, at your expense ($425 hr) to the windtunnel and supply me with the data. For the record............."I've been told that I'm really a nice guy in person".

John, I find it relatively easy, as you put it, to write a paragraph about why don't we just use plywood clamped to the rockers to determine if a flat bottom works. Seriously??? I think that if you are trying to prove to me that a flat bottom car that is designed in a wind tunnel produces more downforce and is preferable over a vintage race car that does not have one is comical. I am fully aware of the advances that have been made in aerodynamics in the last 40 years since our cars were developed. I have raced LMP open cockpit cars at 200mph, I just drove a Crawford Composites DP car at two different tracks assisting a customer of MTI's in setting the car up and clearly understand how the underside of these cars balances the topside of the car and how they work together to keep the car from taking flight. I design and fabricate aero pieces at present for race cars, including my own. I will say this again for the record. Let me paste and copy what I said in my post......... (I have often envisioned a flat bottom 240Z. If you go and try and smooth it out and add a diffuser it actually works against you. I don't need a wind tunnel to tell me that, I've tried it on the track. To make my car a flat bottom, a functional flat bottom, not a smoother under-tray that works around all the crap that is under my car, it would actually require a total redesign of the car. Anyone can add panels under the car to make it look smoother and then a diffuser that looks cool that half the people that have one don't really understand what it really does, I would prefer to leave it alone and not have the extra weight.) Note that I said "MY" car, not just any car. I really am perplexed at your response........... (I'm finding this very hard to believe in light of all the actual racecars that use flat bottoms. I would suggest that if there is a controversy, this would be easily proven one way or the other in the tunnel. I was kind of hoping that you would have a flat bottom since I think you're the most likely person to do it). First I appreciate your thinking that if anyone would have one it would be me, but I don't. I wish I had the money to design an S30 in a wind tunnel from the ground up. Would it have a flat bottom? If the data showed that it was the best way to go then it would have a flat bottom. I assure you there is no controversy, I just don't see any reason to attach plywood to the bottom of my car in a fashion that would not exactly duplicate what I would actually have on my car on the track. Let me assure you that an engineer or aerodynamicist has never in the history of time just attached some plywood to the underside of a modern race car to see the data in a wind tunnel, when they use cad programs to design every piece on the car and simulate the aero in a virtual tunnel before they fabricate exactly the under-tray that is ultimately the best treatment for the car given the data supplied prior to ever even fabricating the first piece on the car. I want my car to be as slick as I can. I would love to smooth out the bottom of my car and create more downforce, however, in understanding how an actual flat bottom tunneled car works, it would require a total redesign of "MY" car. I also understand clearly the advantage of power to weight ratio's and would prefer my car to be as light as possible. I constructed the front splitter, the side skirts and the wing to help air lay on top of them at speed and through practical, on track application, I have found them to be helpful to me. John I am the guy who will hire another, much more accomplished, pro driver to drive my car just to hear his feedback and use all his data to improve my track time by 1 second. I want to make my car the fastest and most fun to drive 240GT car on the planet. I never take a position that I have achieved my goal and there is nothing more to learn, as I try and remain teachable and learn new things that might help me in some way. I do not want to be the guy that spent $500K to redesign my car in a wind tunnel. The definition of HybridZ is what each and every one of us has already achieved and the limit will never be reached. When I got my first 240Z in 1978, it was a '72 and only a 5 year old used car, I was hooked and have never looked back. I hope that you do not take my comments to be an attack on you personally but if you want to see the rewards from a total redesign and flat-bottomed "tunneled" z car, I suggest you build one. If you want to pay for it, I'll build it with you. If we ever wanted to invest in something that would be the most advanced and cost effective way to actually achieving what could be the Ultimate HybridZ then Virtual software would be our answer. There are ways to actually scan your present car in 3D and then run the programs to help answer the questions none of us really have the answers to. I think it might be wise to at least do the due diligence and determine the cost of this approach versus the cost of taking all our cars to the actual wind tunnel. If I had this program I think I would never leave my desk.......... Here is an example of what I'm referring to. http://www.autospeed.com/cms/A_109131/article.html There is a saying that is as old as motorsports itself and really sums everything up................."How fast can you afford to go".

For all that follow this thread............ Keith, "RebekasZ" and I had a fantastic time here in Atlanta at Atlanta Motorsports Park. I really enjoyed working with him and his car is great. We were able to make substantial gains in numerous areas on the road race course. Keith does a lot of autocrossing and drag racing so when he was faced with armco barriers and not an open parking lot he learned real quick to not ovedrive the car and to respect it's limits. Going off at the track has much higher consequences. We worked on car control, braking, head movement, sight lines and weight transfer to name a few. Keith's times reflected his improvement and desire to get faster as the day progressed. Only after a mechanical failure, (brake pads) did we have to retire the car for the day. I was comfortable enough in his abilities to allow him to drive me in my WC Vette at the later part of the day. Always the same comments..............Damn that thing has unbelievable brakes. AMP and Ferrari of Atlanta hosted the annual, "Rides to Remeber" at the track during the lunch hour. Children with cancer are given rides around the track in the Supercar of their choice. Really cool to see all of the kids smiles and all the supercars on track. On Sunday, Keith and I attended Caffeine and Octane. A cruise in with around 800 cars. Everything from a rat rod to an Aventador. This is just another example of how this HybridZ forum brought two like minded gearheads together for a day at the track and could not have asked for a better time. Until next time..................

Mike, Have a great time and be smooth, safe and smart and that equals swift. Taking care of your equipment and a little luck is what will win the raceand you deserve a good long outing. I was trying to work the schedule to get up to VIR and do the Chin event but doesnt look promising. You could always come to Atlanta and do the Chin event the week before at Road A............? Talk to you soon.......

Jimbo, I appreciate your kind words and hope most agree that I try and be as open as I can with anything concerning the car build. I'm in on the wind tunnel and don't mind sharing what we find that works, helps, hurts, etc....... I will say that I apply practical knowledge to my approach to aero. I am fortunate to know some aerodynamicist and fabricators for some pretty elite ALMS and Rolex teams. I asked if one of them I know fairly well and lives here in Georgia, would he come to assist me and the group at the tunnel, He said he would if his schedule permitted and that it would be $1,000 plus expenses for the day. That might sound like an extra expense we dont need but I wanted everyone to know we have that available if we see it is a value worth the $$$. He designed and fabricated the Cadillac LMP cars for ALSM and Le Mans and numerous other teams. In speaking with him, if I ever plan on really making my car aerodynamically slick (as what they consider a high downforce trimmed out race car), I would need to start all over. He likes what I have done to the car and can see how I reached the speeds and times at tracks due to certain items I've fabricated. However he reminds me, the fact still remains that I have a 40 something year old car that was not designed in a wind tunnel, not designed to have 600rwhp and do the things it does. He asks me simply,"What are you trying to do? What are you trying to accomplish? The car wins on track now, isn't that what you were trying to do?". I am interested in seeing the actual data and how the air moves across my car, in person, and be able to maybe generate some new ideas on what may assist me in improving my present set up. In my World Challenge Vette, Its a 2002 C5Z based platform, that was designed in a wind tunnel by GM. It has the baseline for massive improvements in bolt on aero due to the fact that it started its life in a wind tunnel. We will never be able to achieve this with an S30 but we can try and maximize our efforts and improve the cars performance by testing and R&D. I have often envisioned a flat bottom 240Z. If you go and try and smooth it out and add a diffuser it actually works against you. I don't need a wind tunnel to tell me that, I've tried it on the track. To make my car a flat bottom, a functional flat bottom, not a smoother undertray that works around all the crap that is under my car, it would actually require a total redesign of the car. Anyone can add panels under the car to make it look smoother and then a diffuser that looks cool that half the people that have one don't really understand what it really does, I would prefer to leave it alone and not have the extra weight. I can say from practical experience that I try and understand the pitch sensitivity on my car as best I can, and the tunnel is not going to help with that. If anyone wants to road race their car and experiences the type of braking and acceleration my car generates, then my data might help. If you apply my data to your daily road car its not going to work. I have some pretty radical ideas as to how to improve my cars aero package. I just cant do it in the middle of a race season because I don't have enough time between races to make the modifications to the body panels and then get adequate testing done. I don't want to share it out loud until I have personally tried it out on my car (if I ever do), but I will say that it hasn't been done yet with one of our cars. I have an idea of exactly what I want to learn and test in the wind tunnel on my car. I will share the information gathered. If you decide it can help your project and want to apply it to your own build, I have no problem with any of that. The reason we all share our threads is to help one another. I hope that it helps in some way or another but be aware that we are all different drivers driving different cars with different set ups and in no way will we find a universal application in terms of aero that will apply to everyones individual needs. To say that a g nose helps the air move better across the nose because the wind tunnel data shows that to be the case does not mean that a g nose is a better application for a persons specific needs. I will say that we, MTI Racing, are presently fabricating a DTM body for a C6 Corvette. This series will be in the US in 2015. If there is any sports car series that can lend us an insight to what actually works and how different it is to what we all have, then this is the series. All the cars are relatively the exact same car under the different outer shells. The driver and outer shell (aero set up) are the only real variables that separate you from the rest of the cars. The downforce and aero packages on these cars are what you will be seeing more and more of as we move forward. If anyone is familiar with time attack here in the states, it also shares the same traits as these DTM cars. I guess now you know what I'm thinking when I say I have some radical ideas about how to change the performance of our cars when it comes to aero......... Sorry for the rant.................

If taking my car is going to pose a problem, then I will step aside and not go. I certainly don't want anyone getting mad at me for something that is out of my control. I thought my build thread was pretty open and not secretive. I actually know that if anyone hangs out with my team for a weekend can usually get all the info they will ever need about my car. Its not like I drive an F1 car and big $$$ are at stake. I want to know how to make my car better, and this would give me insight into achieving that. When I am at the track racing, other teams will approach and ask my crew questions like, "What pressures does he go out on, How is he set up, camber, toe, All the things that have taken me years to figure out. If anyone looks at my thread they can see that the only time I cant answer a question is when its concerning these certain items. I also know that if we go, I will look to other members who have more experience with Z's in the tunnel. If we were taking Vette's I could offer my experience and be more helpful. I know what works for me behind the wheel under pretty high speed conditions. I think my experience with that is worth something. I also think that I am fairly well suited to try and implement some items that are harvested from the tunnel sessions and apply them to really making the car a better road race car. All of which translates down to anyone's daily driver or track car. We can share results from our sessions as a whole. In other words, share it as a group session. We found that this works and this doesn't, not "well on Matts car this is what we did......". Personally, I think between the group that Mike has mentioned, we have enough to test and get some real data that would be worth our time and money. I also do not mind going with a few members and their cars, paying for the sessions between the few of us and not sharing anything we find. I thought this was going to be fun and enjoyable? Let me know what I can do and what I can contribute...........

First. Relax. We are going to have a great time and there is nothing to be anxious about. I will be bringing one of my cars and when you go out I will be riding with you for the first part of the day. We can then move towards a lead follow session. I have a communicator that makes it easy for us to speak to one another. I have all the confidence you are going to have a blast and possibly learn a few things about your car and its capabilities. We are not trying to drive all day. We are not at a High Performance Drivers Education (HPDE) and on any sort of tight schedule where if your late to class you don't get to go out on track. This is in a very relaxed environment, its a private club. When I go I usually always just give joy rides all day anyway, so If they ask its no big deal. If you want to try your hand at a 60MPH racing kart you can do that, if you want to just sit and debrief our last session we will do that, its no set schedule. Its all about having fun and enjoying the moment, if you end up learning something or setting a new track record, cool........... Don't worry about the lap timer. I am going to bring a crew member to keep track of all your data. He'll make sure all your tire pressures are perfect, he will make sure the car is pre and post race checked, He'll make sure you are buckled in correctly, he will set up Go-Pro cameras on your car so you can watch all the fun at home, you will have a bottle of water waiting for you when you get out of the car, your the pro-driver for the day, All you need to do is show up and have fun............. If you want to bring something that would help. Bring one SD card and one micro sd card. Each around 32 gigs. That way you can just take the cards home with you and download them at home. If you want to watch anything back at the track, we can do that to. Call me during the week if you have any questions. ALSO: If you had any desire to attend the largest car gathering in the SouthEast. On Sunday morning ..............EARLY................from 7am to 10:30am there is caffeine and octane. There will be around 1000 cars there. Every club, Ferrari, Lambo, Shelby, Porsche, Corvette, and yes even Datsun will be there. My friends and I usually attend and then go to brunch afterwards. If this sounds like something that you would be interested in, just let me know. You could show off your car.......... I've attached a picture taken Monday. This is my driving coach, Don Barns, and I going over my technique. Always remember that I'm just passing along what someone took the time to share with me.

Thank you. I am looking forward to having you up to the track this Saturday. I almost fell out when I was at the track for our Memorial Day cookout and a freind asked if I was going to participate in the Rides to Remember outing next Saturday. I said "WHAT!!!!!!!" Its a great cause but I was worried that the track would be closed for this private event. Actually its only going to be during the lunch hour and not effect any seat time with us. Ferrari and Lambo of Atlanta sponsor this event for adolecent cancer patients and give the children rides around the track in supercars. Really cool......... I guess I was being really selfish when I thought it was going to effect our sessions, with all the coordination that has gone into aligning our schedules to accomodate the day......... you know what I mean. Then again what an ass I am for thinking our seat time was more important than giving children, some of them possibly terminal, rides that will light up their faces. Maybe I can do a random act of kindness and make up for it. Glad you liked the video.............

A short video I did that is a great example of "a day in the life" of a club racer. I thank NASA pro racing for giving all the crazies a place to play. Kinda cool because I have a million pictures of my car or the occational camera phone video, but never good professional video of my Z at the track.

Strange thing happend on Saturday. The 914-6 and I were having a great battle, where the lead changed hands 5 times in 3 laps. Neither of my 3 cameras or his two functioned. Quite strange..........as if the race had never happened. My buddy Morris in his C5R caught most of the fun and I hyjacked his footage. I watch it up to the point on the third lap where my tie rod breaks and I plow the field, (actually the bolt that holds the heim joint together sheared off). If I were at Road Atlanta I would have hit something hard, got lucky this time......... BTW.........The 914-6 has an air cooled 911 engine that is putting 450 rwhp and it weighs 2300lbs with the driver, it has 15" rims with 15" wide full race slicks, its center of gravity is about 18" off the ground and it seems to be an 8 foot wide low flying brick trying to race you. It corners unlike most any car I've ever raced against.

Cary, Thank you very much for the suggestion. I think that is a great idea and not very complicated. Its sometimes the most simple solutions that work the best.

Hearing you say you are just tired of missing track days and how frustrated you are with your current set up is verbatum my comments years back about my turbo L28. I have been very happy with the decision I made on the LS.

Mike, I can discuss with you anything you would care for us to do, along with getting your LS setup installed and de-bugged. You only live once and times a wastin'. I thought everyone would get a kick out of seeing the in car video of the race in the rain this past weekend. My fiance came in my office as I was editing the clips and she said, "That's a terrible video. You can't see a damn thing." I replied, "I know, from where I was sitting I had the same view". Car is OK from the spin. The water just ripped the heat shielding from the underbelly and filled the cockpit and my seat up with sand and mud. She will live to fight another day. It's my fault for not having my little hand held swiffer with a micro-fiber towel attached. You cant apply rainx to lexan as it will scrtach plastic. We do apply Novus1 as it has an anti-fog but that only lasts so long. I guess if I wanted a racecar with a defroster, ABS, active handling, windshield wipers, traction control I wouldn't have built a HybridZ.

This weekend with NASA-SE at Carolina Motorsports Park we qualified on pole and when I caught traffic the heavens opened up and the race was on in the final few laps. The better driver won this time around but second overall in unbelievable conditions felt pretty good. Here is a clip of the final few laps to give you an idea of what I'm talking about. Next time it rains and they cancel a NASCAR event.........I'm gonna laugh.

How about Saturday June 1st? Atlanta Motorsports Park all day, or as much as you want. If you have never driven racing Karts you can do that as well. I have a chatter box for the two of us to communicate with each other. Do you have any data or lap timer you could use? There are some apps for smart phones as well. (Harry's lap timer is one Ive seen people use). This is a good tool for us to chart progress. Let me know if that works for you? If so we can discuss accomodations. Do you have GoPro camera's? If not I do and you can just bring a few SD cards to use. Go ahead and call me so we can discuss details. Looking forward to it........

There was a nice article in Speed News this past month about our race at Road Atlanta. HybridZ kickin some ass.......... http://www.derdizmedia.com/publication.aspx?pid=16&pkey=yqtbafxce&pageid=74

CCW made my wheels and they are awesome. I called BBS up the road from us (MTI Racing). They knew who we were and even offered a discount. I indicated that I wanted the same three piece race wheels that I had on my first 240 race car 28 years ago, just not 15inch. They said they no longer made the "snowflake" pattern but had the mold and would reproduce it for me, how many sets did I want. I said we probably were going with three sets, one for rains and two for slicks. He said no problem that would be $30,000. There was a long period of silence as I was getting up off the floor and tryng to catch my breath. I said I really appreciated his time and would get the specs and call him back. I obviously was born at night but not last night...................I can build someone a great track car for $30k. I called CCW and they were able to make the three piece race wheels I wanted for $2,800 a set. (THATS ALL 4.) They called it their Classic pattern with a stepped lip and would anodize them in gold and it would take around a month to get them. If anyone has seen my car in person you would attest that the wheels are very period correct and look outstanding. I highly recommend CCW and have used them on numerous projects, all with great results. They work on their own time and dont like to be rushed, so dont order them and call them every four days wanting to know where your wheels are. I cant get into exact set backs but will say that mine are 17 x 10.5 and 17 x 12.5. I run Hoosier R6 315/30zr17 front and 335/30zr17 rear.

I'd love to see the pictures. Could you give me thie link to your thread. I'm sure it looks fabulous. My car does not have the pinstripe. At 160mph you cant even notice............

I thought this shot came out well. It was taken with the GoPro black series Hero3.

A fellow racer just sent me this pic of the start of the race this past weekend. Gotta love a HybridZ on the front row.

I really like the pillar aero treatment, mine is duct tape presently. I'm going to steal that design or at least go in that direction. Its something Ive been wanting to do for a while. I want to incorporate the quarter window in the design as well. Diamond plate works but is heavy compared to other composites. Was that a budgetary decision? Which I understand better than most......... BTW........The fender vents work great and I did some vents on the rear flares as well to release the pressure. Just cut vents in the rears and did mesh then painted flat black. Check your schedule for July 20-21 for the NASA races at VIR. I will be staying over for my friends Monday event on the 22nd as well. Join us for a great three days...............(I usually will get a hotel room for Tuesday and sleep for 18 hrs before trying to drive home)

I also have had a few people ask me to put a camera in the footbox to show the activity. This is from this weekends race.

Thank you Tim. If someone comes to one of my races and hangs out for the weekend and has a few beers with the guys I'm sure they will know everything they need to know. Hell........we'll put 'em to work. This past weekend was special. We had our Sat. and Sun. NASA SE races at Roebling Road in Savannah Ga. The weather was perfect and the track was fast. We did our warm up Sat. morning to scrub a pair of stickers and get a feel for the conditions. When I came in we noticed a pool of fluid under the car. The remote Tilton reserviour for the brakes had dumped. We had to disasemble the entire piece, rebuild it and install it and we barely made it to the grid for qualifying. Qualified on pole. We jumped out to a 20 second gap over second place, a very fast 914-6, but with four laps to go my clutch went to the floor and stayed there. I managed to get it into fourth gear and did the last 4 laps in fourth and just squeeked out the overall win. When I came off track I just shut it off and we pushed it back to the trailer. It took a while but figured out that the Tilton master cylinder had crapped out, each pedal has a small remote MC right above the pedal. We removed it and realized it was pretty much over for the weekend without a Tilton rebuild kit or a new MC. There are a few teams that have some extremely talented mechanics on them. I had them look at it and they tried but said it was a lost cause. Thats where a little redneck engineering comes into play. My guys took Bic lighters and heated it up as best they could without melting the rubber seals inside and broke it apart, all while holding a beer in the other hand. They cleaned every little nook and cranny and reset the seals. It seemed as if a minute sliver of teflon had worked its way next to the seal and was allowing air to work around it comprimising the hydrolics. We reinstalled it at 2am and they all said they thought it was good to go. Thats going from the outhouse to the penthouse. The next morning the car wouldn't start. The heat shielding around the starter had somehow pulled the ground wires off and that was not hard to fix but when you have 30 minutes till qualifying it isn't in the morning game plan. We qualified on pole again. We won the race and set a new class track record and personal best 1:14.3 I dont think its possible to have that much fun with your clothes on anywhere.

Jimbo, I would love to tell you the particulars of my setup but I cant. I have a non disclosure agreement about data sharing. I can tell you mechanical pieces on the car or what we have fabricated but it gets touchy when my competitors know how I set up my car. I know this seems very stupid and personally I dont think its a big deal but Ive gotten in trouble for this sort of thing in the past and I'm sorry. If I was the only person on my team I would share the info......

Putting the fender vents in and I really like the look as well as the functionality of them. They are carbon fiber and aftermarket replacement hood vents for a new Shelby GT500. Only $149 for the pair. I am actually putting the unfinished side up and the shiny clear coat side down to make them function better, (the opposite of how they were designed to go in). When the vent or louver is extruded it creates more of a vacuum over the vent and thus not just letting the positive pressure out but pulling it out. I am surprised that no one has commented on the article that the NASA magazine did on the car. I was sorta proud of it and it really shows off what, with a little effort, fabrication and money a HybridZ can be pretty formidable. If you like racing, the magazine has lots of great articles. One of which is on my dear friend and Z enthusiast John Evans. He races and is the race director for the Spec Z race group. Next race is next weekend at Roebling Road. I have a 427 928 Porsche, a 914-6 Porsche and a badass firebird to deal with in my group. The 914-6 is going to very hard to beat as he has 400hp with only 2100lbs and a ton of aero. All my cars strengths have been nullified by the slower tight track and his car sets up better. I'll give it my best, but I have to be realistic. The following weekend we are at Barber Motorsports Park. Wish me luck..........