CarlB

My car has the Caterham AP brakes. The regular brakes are very good, but if you really use your brakes the AP brakes are better. At the time of the test, I think the car could have used more rear brake. I do not consider myself a very good driver and I had never been to that track. I had the car setup so I wasn’t going to get in trouble. If you get a 420R with 200 HP you will easily be faster than a MX-5 factory race car.

I use my Caterham for track days. Everything you like about your Miata will be better in a 7. Last year when I went to a new track, I followed a Miata I though was well driven to learn the line and understand the track. The next session I followed for a bit, and when we came in his comment was wow can that thing turn. It is like hooking your brain up to the tires. There isn't any delay in response. The seating position is as far back as it can be and that gives you a very clear idea about over or under steer. Depending on the power the car is very easy to drive with the throttle, and they are very easy to drive. I let the guy that does all the track testing for Grassroots Motorsports magazine drive my car. We had had some correspondence over an editorial he had written that suggested people would stop building their own cars and buy factory race cars. He was very impressed with the driver assist in the car. I pointed out I had a car without any assist that was better, and he politely disagreed. At an autocross I let him drive the car. When he came in from the run, he removed his helmet and looked up to me and said this car does everything right. Drive one, you will love it. The parts are easy to get and there are UK suppliers that are selling part to the US all the time. One very good one is Redline. There are dealers and they all seem to have a good reputation, but I do not have any experience with them except one. Beachman Racing knows their stuff and are great to deal with. For me being on the East Coast, it is a little more challenging to get parts from him, but his help can make it worth it. If you have a track toy Miata, you have accepted a higher level of maintenance than a street car. If you use the car on track, you need more maintenance, but a 7 isn't high maintenance compared to a race car. A lot depends on how much power the engine makes. Faster cars require more maintenance. Brake pads last a season. I am 75 and not as flexible as I once was. The cars are easy to work on. I mentioned the Grassroots editor. He did a video track test on my car. He compared my car to one of the Miata factory race cars that are used in the MX-5 cup, and my car's time was a little faster than the Toyota Supera. It is an old video, but I think it is still on their site. My car at the time had about 180 HP and was on the Avon street tire called the ZZS.

Thank you for that information. My wheels arrived on 2/24/26. That was the first day the tariffs were supposed to be lifted.

I recently purchased a set of Revolution wheels from the UK. UPS sent me an email to pay the tariff before they would deliver. The tariff and processing charges were 104.00 dollars. I actually order the wheels, and they were shipped 1 day after the Court said the tariffs were not legal. That did not matter is what I was told. Last week I got a letter from UPS saying I still owed over 500 dollars more. They think I got 32 wheels. The other thing was for the exact same wheel with the same description on their invoice one after another the tariff charge was 10%, 25% and Free.

Yes and less than impressed. It is a little clumsy to use and I am not confident of the accuracy. Some people like it for at the track use, but I have Dunlop gauges and they are very accurate.

Croc pointed out that MRF is making a tire that looks like a possible choice for our cars. MRF is a large manufacture and has a good reputation for Rally tires. Here is a chart with what I believe is the tire in the test Croc brought to our attention and their F-3 Tire. MRF Formula 3 and Formula 4 Racing Cars: Slick Brand / Pattern Tyre Size Equivalent size(For Reference) Std Rim Width*(inch) Section Width(mm) Tread Width(mm) Overall Diameter(mm) NSD(mm) Compound Application** ZTD1 200/540 R13 225/45 R13 8 225 / 8.84 195 / 7.68 540 / 21.26 2.8 H/M/S/SS Dry Racing 240/570 R13 275/45 R13 10 280 / 11.02 245 / 9.65 575 / 22.64 2.8 H/M/S/SS Dry Racing MRF CIRCUIT RACING - SLICK / WET / INTERMEDIATE Brand / Pattern Tyre Size Equivalent size(For Reference) Std Rim Width*(inch) Section Width(mm) Tread Width(mm) Overall Diameter(mm) NSD(mm) Compound Application** ZTI2 185/60 R13 175/550 R13 5.5 190 / 7.48 175 / 6.89 550 / 21.65 5.8 H/M/S/SS Dry to Damp 205/60 R13 195/580 R13 6 210 / 8.27 190 / 7.48 575 / 22.64 5.8 H/M/S/SS Dry to Damp

I live in Fairfax and have the ones for a S-3 if you would like to try them. They are not currently in the car. PM me if you would like to try them. The ones I have are the FIA approved race seats. They are much stiffer than the ones that come from Caterham.

Both Croc and Bruce have good points. I think Croc's point about modifying a car designed before aero became important is a very good point. I think one of the best parts of a sevens handling is the soft suspension. It makes the car predictable and makes the tires work better. The article, Bruce and Croc talk about the need to increase the spring rate to compensate for the aero load, but I want to add that the aerodynamic center of pressure moves as the rake of the car changes. Cars with lots of down force wind up with very stiff springs to limit the center of pressure moving back and forth, not just to compensate for the additional load created by the aero. If the center of pressure is moving the oversteer / Understeer balance is moving.

If you want to see a domestic engine that could make similar power, look at the Polaris Slingshot engine. It has 3.5 inch bore and would be capable of the engine speeds in a racing application. I might suggest a slower speed for something on the street.

I have the same gearbox and have not noticed any noise off throttle, but I have to say my car is loud. If you have the aluminum case, there is a drain and fill plug. The fill plug is not accessible on a S-3 Caterham but might be on a Burkin. Change the oil and see what it looks like. I think there are other good ideas mentioned here as well. Tracsport specifically recommends The Redline oil.

I have use Hooser F-2000 - F-Continental FB tires in both radial and bias. Hooser is the spec tire for Formula Continental (FC), and my best friend runs one of those cars. He had a set of radials after the class switched back to bias ply tires for cost reasons. Hooser does not make the radials anymore. The set of radials I have are the hard compound, because that was the spec tire. It takes about two laps to get temperature. The bias tires are also the hard compound, and it takes about the same amount of time to get them up to temperature. I now have a set of the bias plies in 35B, but I haven't used them yet. I ran the bias plies with the same set up I used with the radials and did not see a lot of difference. I had a little more understeer, but I suspect it was the radial tire set up with more camber than I suspect the bias tire wants. The only Avon's I have used are the ZZS. The Avon radial acted more like a radial to me. The turn in is sharper on the Avon. The Hooser's aren't as sharp on turn in, but when they set, the grip is really great and it is very easy to stay in the high grip range.

Is the 150 MM measurement for the front ride height with Avon 13-inch tires? I was running my car lower and am having trouble getting the bump steer where I want it. I think it is probably because the instant center is moving around too much. The car has short control arms.

I have had a trailer going out of control because the load shifted and it lost tong weight. DO NOT STEP ON THE BRAKES, AND DO NOT MAKE ANY FAST MOVES. SLOW DOWN SLOWLY AND KEEP IT IN A STRAIT LINE. This was with a 3/4 ton Suburban and a 7 thousand gross weight two axle trailer. I had 3 chevy engines in the back and they shifted so two were behind the axles.

As always, this is something I always look forward to. Thank you for putting it together. I have saved the date.

Sorry - The Porsche has been sold.