sf4018

The problem with the fuel pump module is it's guessing the amount of fuel needed, there's no feedback loop to correct any changes in fuel quality, fuel pump efficiency, etc. I had the same problem as you some years ago on track before the FIA fuel tank/ECU changeout project. I believe the racing 420Rs use an always on external fuel pump with return to tank through a pressure valve, which I basically copied. That said if you don't want to change out the fuel system I reckon swapping out the fuel pump would be a good first step as Croc and MV8 have alluded to. Maybe the pump has lost just a few percent of pumping efficiency but maybe that's enough to send it over the edge on this flaky system.

Correct.

This set will be perfect for a racer who needs a backup set for rainy qualifying or race sessions. 2 Fronts: used 13x6” Black Apollo Wheels. Tires unused Hoosier W2 185/65R13. 2 Rears: used 13x8” Black Apollo Wheels. Tires unused Hoosier W2 205/60/R13. 4 x 108mm (4.25”) PCD. Set is balanced. These tires are track only, not street legal. The tires are about 2 years old. Wheels are 4 years old and have had a few sets on them prior to these, they are in good condition but not new. ZIP is 35213. Make me an offer.

Purchased in 2022, used for 3 years, but no longer needed. Part number 380X0006A. It works great, has some imperfections of the polished chrome as shown in the picture but otherwise normal condition. For reference the new part is this. https://caterhamparts.co.uk/silencers/6839-exhaust-silencer-7-duratec-side-exit-polished.html?search_query=380X0006A. New price is $740 + whatever import duty is applicable. asking $290 obo + shipping. Current ZIP is 35213.

I had a series of blown coils a few months ago - turned out to be a frayed wire on the ECU harness where the harness rubbed occasionally against the drivetrain below. The frayed wire was for coil #1. For some reason that occasional grounding out caused the coil to blow (I went through 4 coils in one weekend before figuring it out). I repaired and zip tied the harness to make sure it doesn't touch anything, didn't have any more issues after. It may be worth checking out the loom wiring for wear.

I've a had an engine loom wire that fed to a coil fray and fail due to rubbing of the harness on the engine, it was really hard to find since it was intermittent and also underneath the loom. I would verify the loom is in good shape physically and electrically between the coil and ECU. Maybe you've done that already.

Try bleeding the brakes and see if any bubbles come out, maybe the fluid is boiling. If so, check the specs for your brake fluid. The fluid I use has a boiling point of 310C for racing. If you have a handbrake check the rear pads for wear, that may be another reason for drop in fluid level, the standard rear pads wear super fast on track.

No, should not need to do anything with the prop or diff. Verify Your angles and clearance under the chassis is sufficient though. You’ll need to take the starter motor off the front left of the engine. It is close though.

Pull the engine with transmission attached, the disconnect will be between the back of the gearbox and driveshaft. I know it feels like you'll be undoing months of work but it's not as bad as you think, about 4 hours. Most of it is draining and pulling out the hoses.

The 1/4" spacers did the trick. I could only get slotted spacers at the local parts store so centering was a rough guess and there was some vibration but it was ok. But the 5 race laps I put in the R7s seemed good, held up to the intense heat (95F) well. It held up better than I did, I pitted after 5 laps as the mustang in front was dropping oil, I was completely covered in oil by the time I came in and about to pass out from the heat.

R7 update: It takes 100 clicks on the fronts to get the correct rake (due to the very narrow rears), but there's enough ride height to get by without having to lower the rear suspension, so that's good. The bad news is I need to add 1/4" spacers on the fronts, there was a significant amount of tire rub on the corners with the wingstays.

How I feel when working on the LSD... (volume on)

You talking about these? I would contact dealer to get the right ones even if you find something quickly to keep the project moving. They are pretty easy to swap out.

Regarding the BFH, on the 2nd time installing the diff (after a shaft replacement) we needed some real power to get the top bolt in. We couldn't get enough power under the car (not enough hammer stroke) so we taped a threaded rod to the long bolt head, long enough to poke out into the wheel well area, then use a masonry hammer outside the car, can really put some power into it. Good times.

Try adding a light or some indicator temporarily to each of the outputs to the relay circuits relating to the engine starter/ignition, maybe something strange is happening to the key wiring.

If you don't have luck try this - remove each of the 2 shorter bolts below one at a time and replace them with narrower screwdrivers than the bolt, this will allow enough play to move the diff around a little but still hold it in place. Then you should be able to move the diff to straighten up the exit for the long bolt and smash the crap out of the long bolt to get it through. Once the long bolt is through working the diff for the shorter bolts is a lot easier, use a hydraulic jack to align the LSD to the chassis holes. Stuff of nightmares.

Here you go... For the trailer you can definitely use the rear wheel as well, that's probably more standard way. I just got into the habit of using the sub frame as the rear wheel area is usually too hot to handle when loading after a race. It all works, the car is so light anyways.

The previous dyno we tied off the rear of the car at the sub-frame (the circular tubing), also do that for transport on the trailer.

I have a 6 point harness for racing, I don't see a benefit of a 7th. I also use arm restraints to keep limbs inside and Hans device to prevent neck injury on front impact. The biggest risk for my setup is lateral impact to the neck. I believe some people have installed a halo (from a radical?) and bolted to the roll cage, which is ok but the problem with that is the standard Caterham race seat is not secure with only 4 bolts connected to the thin aluminum floor on the bottom (normal race car seats are bolted at the back to the roll cage as well as the floor so they will not move at all) so there's definitely potential for seat movement on impact. I wish there was a better racing solution for the seat, I tried to find a seat with lateral head support but was not successful finding one that would fit, they are all pretty bulky and flair out too much on the sides.

Do tell

I had the same, it is odd. I coiled it up and strapped the down beside the engine somewhere, you don't want it hanging down below the chassis or flapping around in the wind.

Have you checked for any nicks or scratches around the top edges of the tank where the cap screws down to?

What are the hot/cold pressures for the R7? I’ve never run them before. The spec sheet has these pressures but they seem high.

I would guess it's a mechanical issue in the tach. No idea if it's serviceable.

The front suspension is easy access, just jack up one side, make the adjustment and repeat for the other side. The rear suspension can only be accessed from underneath. I don't have the trailer space to put in a hydraulic lift so putting it on jack stands is the only option, which is time consuming, especially if I have to repeat a few times. Maybe at the end of the day but then I'm eating into beer time