bb69

Some people asked about my project in some other threads, so I thought you guys might appreciate the car I am building. This car is not a Corvette, but it based on all C5 suspension and powertrain. It will be a two seat, mid engine car for the track only. It will use a LSx engine mated to a Corvette C5 transaxle directly. The powertrain will be long, but it's much cheaper than a Porsche transaxle and stronger than an Audi box. All the suspension pieces will be pure Corvette.

On to the pics. First are some of the screenshots from the CAD model. After that are some of the pics from this weekend. I have made the lower cockpit outline using 1.5x3x.120 rectangular tubing. All the round tubing is 1.5x0.90 DOM. I am also utilizng sections of the Corvette frame in the rear so I didn't have to make the suspension mounts. Enjoy:

0Randy@DRM

You sir have a lot of work in front of you!!!

I will look forward to seeing more pictures of the progess.

Randy

ReddyZ06

Sure looks like a huge project, but i imagine that is a great part of the fun.
Mike

2000BSME

wow! looks like a slushbox! that's what I drive too. maybe we can share some go fast secrets. THE biggest problem that I have encountered is keeping it cool. Larger capacity resevoir and lots of cooling is needed.

bb69

I was not planning on using an auto, but the alternatives are much more expensive. The C5 manual cannot easily be mated to the engine directly because the shifter comes out the front face. It is also longer than the auto. The other mid engine transaxles are Porsche, Ford GT, Pantera, etc (out of my budget), or the Audi (too weak). What really closed the deal on the auto was the discovery of paddle shifters and a cheap transmission controller. I am currently using a Megasquirt computer to control my 69 Vette engine. The guys at Megasquirt are currently testing a 4L60E transmission controller. By the time my car is ready, I expect the code and hardware will be available and fully tested. I plan to combine this with paddle shifters to have complete control over the auto. I have been reading your's and other peoples' threads about keeping the tranny cool. I will most likely use a large cooler and electric fan.

The project is big, and it quickly teaches you that you don't know as much as you thought. I had originally planned on modeling the whole thing in CAD, and then simply building to the plan. It didn't take very long to realize I can't model for beans, and it's hard to figure out the "soft" stuff. What I mean, is things like what will the cage look like from sitting in the seat. The last thing I want is to have the a-pillar blocking my vision. Things like the seat angle and distance to the brake pedal are also hard to model without first trying it physically. So, now I go back and forth between building and modeling.

The building is fun. I am trying to keep my ultimate goal in mind: to actually drive the car. The only thing better than perfect, is done.

Thanks for the compliments.

Ken

2000BSME

FYI, I added another trans cooler, in the trunk, and I still was overheating after 5 or 6 laps. I think the main problem is not enough resevoir capacity. I need to add an additional 8 quarts or so of fluid capacity and even MORE cooling capaicity! I was running 1:47's at Barber this weekend, which I was VERY happy with, considering this is my 4th 2-day event, but I always had to pit in after a few laps due to overheating.

Keep it cool, keep it cool, keep it cool. I don't think a race car can have too many or too big a trans cooler, that is, if you go against the grain like we are, with the autos!

69427

Looks great, man. I love seeing someone do something unique or custom. May I ask what size rectangular tubing you are using for the frame? I'm about 90% complete with putting a C4 suspension on my spare C3 frame. Given all the stuff I had to cut away, and all the surface rust I had to sandblast/grind away to get clean metal to weld to, I came to the conclusion if I ever do another project like this I am going to build it from scratch, rather than dealing with 35 years worth of surface rust.
Again, looking good! Keep us updated with ongoing pics.

ps: Perhaps Jim Hall might sell you some spare Chaparral bodywork for that. : )

bb69

2000BSME,
How big is your cooler? How much extra capacity does the cooler add to the system?

69427,
I ended up with 1.5x3x.120 rectangular tubing. Of course, I did all the original design with 2x4x.090. When I called up the local metal house, they didn't carry anything less than .120 wall thickness. That was going to add something like 50-100 pounds to the chassis the way I had it designed. The 1.5x3 ended up being a pretty decent substitute, but it's pricey. I know the price of steel has gone up, but when they charge $125 for a single length of tubing, it's hard on the heart.

I know I have seen some of your posts about the C4 transplant, but do you have a link to some threads, or some pics you can post?

Thanks again,
Ken

2000BSME

I bought 2 10 X 8 x 1.25 " fan cooled Derale Atomic cool coolers, which only added an addition quart or two, and they only prolonged the inevitable overheating problem.

Anyone who tells you all you need is a really good cooler, isn't going very fast. You need rediculous capacity and cooling.

Both of my Derale coolers ($400 total) are rated for 30,000 gvwr.

I probably need at least double that. (120,000 gvwr).

thanks and I'll let you know if I finally resolve my problems.

Aardwolf

That'll keep you busy!

Keep us updated with pictures, your project is very interesting!

Good luck!

burners

That is pretty cool looking. I've been kicking the idea around of doing something like this. I will eagerly await updates. Projects like this are pretty neat to watch.

69427

Yeah, I've got some pictures I've taken along the way. I'll post them sometime soon in one of the forums, as I don't want to dilute the uniqueness of this thread.
An item that I've spent a lot of time trying to correct on the stock frame is the poor torsional strength. I'm particularly interested in how you tackle this issue on your frame.
Again, please keep us updated with pictures.

69427

I'm running manuals in both my Corvettes, so the following is just my philosophy:
I agree with the need to have a good efficient cooler for all the liquids. I'm presently unconvinced about the use of a large reservoir for the trans fluid. A reservoir has no inherent cooling function, and seems to be, at best, thermal mass/inertia, and at worst, several pounds of unproductive ballast. JMHO.

69427

Just posted a couple pics in the C3 Tech forum.

2000BSME

ouch! You would be wrong about that. Hydraulic resevoirs are designed with cooling in mind, and the larger mass of oil gives the system more heat absorbing and dissipating capacity, which is exactly why my thoughts are in that direction.

69427

Reservoirs do not increase the dissipation capability. Do the calculations for surface area (where the cooling occurs) versus the volume in a typical reservoir shape, and you will see that the ratio is very poor, exactly the opposite of a cooler, where there is a large surface area relative to the volume of fluid in it. As I said earlier, a reservoir is thermal mass, and is different than thermal conduction.
I'm not trying to get into an argument, or be disrespectful, I'm just doing the math. As a person who also tracks his car, I'm glad to see that you are using and enjoying your car for one of its prime purposes: Speed.

69427

Looking forward to pictures and data of the balsa wood model you mentioned in another post. (I enjoy the technical aspects of this sport almost as much as the track time.)

73-84 IMSA Widebody

I carry 16 quarts of oil between dry sump, reservoir, dual filters, hoses, and cooler. I have to believe that the volume recirculating thru the engine half as many times as an 8 quart system has to reduce overall heat. I also believe that the entire drive system heat is additive. IE if you cool the water and trans but not the oil...guess where your heat problem will come from. Auto trans produce tremendous heat and if coupled to you radiator will add heat to the engine. I admit I'm not a physicist .... but I did stay at a Holiday Inn Express once
PS...very cool project, good luck!

petefias

Holly smokes! You got some ***** (Big Block/*****) to start from scratch. Your setup is very similar to the Mongoose GTP kit car. Aaron Quinne has one built and I wondered why he went with the slush box, now I know.

Your reference to the cost of the Porsche transaxle makes me believe you've explored the factoryfive GTM alternative.

What body do you plan to use, target weight?
You will find hundreds of questions popping up should you decide to post your build progress. You my friend started out on a true life experience. I hope you'll have enough patience and persistance to see this remarkable project to its completion.

Both the FF GTM and the GTP are great alternatives, but their cost is nearing a full race car cost. They make you consider Randy's (DRM) race car build offer.

Please keep posting about your progress!

2000BSME

no need to do the math, as I've got many years experience in those types of calculations and know how it will turn out.

While not a major consideration in hydraulic resevoir design, cooling is considered, and it does add to the overall cooling capacity of a system.