KnifeySpoony

I have 5 track days on my pads - the rears looks like they can still do another couple I would guess. Definitely wearing faster than the front, presumably due to higher temps from using a solid disc. Fronts look new. I guess I will just have to do some experimenting of my own. Unfortunately few brands make pads that fit our standard rear calipers. Lots of choices on the front though. Does anyone know what the OEM pad is on the front 4 pots?

My 420R has the uprated 4pot front calipers on vented discs with the standard solid rear discs/caliper. My understanding is that caterham fits this setup with a higher friction rear pad (Delphi 507, whatever that is) to help compensate for increase brake torque up front. It seems to me that my setup is still under-braked at the rear. I had pondered going to the uprated race-setup rear calipers/rotors but I was hoping to try a higher friction pad on the rear first to see if it improves things. Does anyone know what would be an appropriate pad that would be a step up from the delphi pads and be a good match for the 4 pot fronts? I am reading about the Ferodo DS3000 as a potential option, but I'm not sure how well it would match up. Thanks

Amount of body roll/suspension deflection with bump will also be determined by spring rates. From my reading, many Caterham drivers like the rear steer feeling that the deDeion with radius arms gives, maybe it's part of the 7 experience? I chose watts for my build as I want a more predictable/stable chassis. My car is primarily a track car. I can induce rear steer in other ways that are under my control (my philosophy anyways).

If you don't want roll steer, consider adding the watts linkage. I chose that for my recent build.

Resist temptation to buy stickier tires, keep learning the car and shedding time on track. Only upgrade to ZZR after reasonably plateaued. Modify battery tray and install the antigravity battery I've had sitting on the shelf for many months. (aka add some lightness)

For me it's "it's a kit car". Other answers I have developed in my ~6 months of ownership: "4 cylinder" "not that fast" "about 200hp"

That's typical. You'll be convinced you're missing something, only to find it in with other completely unrelated parts for some reason....

Correct me if I'm wrong, but I don't think this would be an application for a Nord lock or other serrated washer, as they need a flat surface to bind into. Yeah, I'm not sure tbh. I think I will move the suspension through its range and see what is moving - my assumption is that the bolt head will turn with the link as it rotates but I could be wrong. I guess in theory the bush within the link end should be clamped against the boss on the outer chassis rail, and only the rubber should deflect? ie when I move the axle up and down, the link should rotate but the head on the bolt should stay still. I know there is indeed a lot of lateral force - the whole de dion moves laterally under cornering load - this is easily visible in trackside photos. This means the watts links have to deflect significantly.

Ok, I like the suggestions- keep em coming. I'm also considering putting a thin teflon washer underneath the metal washer under the nut so that it rotates more easily on the chassis boss and doesn't apply as much torque to the nut.

My 420R has the watts linkage. The rear link on both sides of the car where it attaches to the chassis is held on with a bolt and nut (nyloc nut inside, and bolt head outside in the wheel well, each side with a flat washer). These fasteners repeatedly loosen quickly on me. (EDIT: NOTE - the faster is coming loose, but the nut is not turning/coming loose based on paint markings; see blow). I have read that others have had this issue as well on blatchat. What I mean is that after every single drive, the fasteners will need tightening. I will take about 1/16th to 1/8th of a turn to get the torque set properly (34N/m). No other fasteners on my car (not even the forward watts links) have this issue. I am trying to figure out a solution for this, possibly changing to some type of locking washer or loctite or cotter pin or increased torque or??? Any thoughts from anyone with some engineering prowess? Thanks

Agree about the stands- do you have a jack that goes that high? If not, how will you lower it back down after it's too heavy to pick up....?

OK, did your settings and it seems to have fixed it actually. Maybe reading just a couple percent high compared to numbers in easimap. I can't believe that Caterham is unaware of the dipswitch settings. They had me purchase the easimap cable in order to change ECU tunes when it wasn't necessary at all. SMH.

Thanks! I will play around and see if I can fix it.

Do you recall what the proper dipswitch settings are?

I just became aware of this document: https://www.caigauge.com/documents//product-instructions/tachometers/pil055-iss2-279.pdf I thought that new Caterhams don't have the switches but a recent thread on blatchat suggests they do: https://www.caterhamlotus7.club/forum/techtalk/360-rev-counter-reading-approx-half-actual-rpm Can anyone confirm the proper dipswitch settings?

Agree, something is off. Torque curve shouldn't look like that on a 420 I don't think. Mine is just starting to pull at 5k.

does this need anything to mount over the standard roller barrel pipercross filter housing?

If Caterham can't resolve this issue, then that will probably be what I will do. I was already considering going to an unlocked ECU so I could do a proper dyno tune, as I've heard that might unleash some more potential in the engine. However, it runs great and pulls hard, so haven't been motivated to do so.

I am aware of the 1:4 pulse issue - I have been told that there are only 2 possible settings for this (from Caterham), and i have tried both of these settings. However, neither are correct. It seems my tach is off by a different factor (ie not 1/2 or 4x the correct reading). RE: easimap - it does show a bunch of different sensor info, but I don't have full access to each setting. I can update the ECU software but it just replaces the entire software file with ones provided by Caterham.

The "real" engine numbers I am quoting are from easimap.

I hadn't considered that the ECU hardware itself could be faulty. Caterham mentioned me sending the tach itself back...

I just realized my sticker doesn't say SPCNS on it- is that gonna be an issue with regards to smog testing?

My 2021 build 420R still has a misreading tachometer. Apparently there are 2 possible calibrations, according to Caterham. Unfortunately, one reads high, and one reads low. With one calibration, the tach reads high by about 50%. With the other calibration, the tach reads low by about 1/3 (ie with actual RPMs at 3000, tach shows 1000). I have read about older Caterham tachs having internal dipswitches, but my understanding is the newer ones don't. I am still working this issue out with Caterham, but has anyone heard of this issue? Thanks

Just got back from BAR referee in Livermore...

item is sold