JohnCh

Ignoring whether or not a new Caterham is worth the money at current prices, they are sufficiently expensive that a number of alternatives suddenly become realistic options for buyers. I'm curious if the really long waiting list is still a thing? I waited over 17 months after placing an order in 2021, but there have been at least two significant price increases since.

A no-options 420S S3 is 42k GBP which is $53k at current exchange rates before you factor in shipping. In my case, that added $8k to the bill. Unless those prices have dropped considerably, even a stripper 420 is a $60k car delivered to the West Coast. Option up a 420R SV and it's not hard to cross into new Porsche Cayman territory. Things have changed.

You might get more targeted answers if you update your profile with the type of se7en you own (it shows you are still looking). On my Westfield, I am using this model from Protex with the optional latching pins. Protex has a huge number of choices, and their latches are high quality. Unless you are okay drilling new holes, I'd pay attention to the mounting hole locations for your current latches. https://protex.com/27-1570MSZN-spring-claw-toggle-latch-with-safety-catch-light-duty-mild-steel-zinc-plate-passivate-silver-blue

Superformance S1 located in OR: https://www.facebook.com/marketplace/item/1081099910487213/

Hard to be certain from the video, but it looks like the outer MC has a lot more side-to-side room on the balance bar than the inner MC. What happens if you tighten that up?

Keith Tanner, the author of the GRM article, also wrote a book many years ago titled "How to Build a Cheap Sports Car" which is now out of print, but copies do come up on the used market occasionally. I'd spend time digging through his build diary here. It should help crystalize what's involved. https://cheapsportscar.net/diary.php?start=1 I'd also join https://www.locostusa.com/forums/ and https://locostbuilders.co.uk/forum/ if you haven't already done so. USA7s is not focused on any single brand, but the majority of owners have cars that started as kits from various companies such as Birkin, Caterham, Stalker, GBS, MK, WCM Ultralite, Westfield, etc. Although there are Locost owners here, and the requisite knowledge to build one among several of the members, you won't find as much on that topic as you will on those dedicated Locost forums. Belonging to all of the forums is a good approach, as-is digging through various build threads to see how some of the companies I mentioned above do it. At this point reading everything you can get your hands on will be helpful as you build your knowledge base and develop your build plan. I'm looking forward to hearing what you decide to do. Cheers John

Welcome @Cirving! For those interested, Cirving has also created a dedicated thread to his car. Turbocharged bike-engined se7en. Yeah, that's a sedate ride

Hmm... perhaps @Croc should take a page from your playbook and use that for his new signature?

Vlad, I misinterpreted your earlier comments and thought it was going back to full throttle that caused the problem, hence my earlier -- and incorrect -- comments about enrichment.

I'm confused by the two statements above. Has this issue been there for years and the impetus to your initial troubleshooting, or is this more recent? @MV8 even if that portion of the map should be pulled up, would a change there (light-mid throttle and mid-high rpm) address the issue Vlad describes above and quoted below? Or Vlad are you saying it's after full throttle, then back on the throttle again, but not at full throttle? i.e. Full throttle > off throttle > light to mid throttle?

This is key to understand. When did it start, when does it happen -- e.g. is it only when you describe it or are there other less severe issues that might be related? is it in specific rpm ranges? how sensitive is the severity of the issue to the load delta or rpm? -- and did anything else change leading up to the issue? Also, if it is as severe as you write, and you had a competent individual map the engine, then I would look towards mechanical or electrical issues. Could there be a wiring issue that is triggered from the movement of the engine when you suddenly back off like you describe? is there an issue with the injectors where they are not opening up as quickly as they should? is there a problem with the TPS that reacts badly to rapid movement? etc. As for the map changes fixing it, try visualizing where your throttle position and rpm are when this occurs and see if that is actually in the map range that you adjusted. If you were really going full throttle, then that is not an area of the map you touched.

@Vovchandr Based on your description of the issue, I'm not sure that change should have made a difference. I'm curious to hear from people knowledgeable in this area, but it looks to me like that is the 3D graph which shows the amount of fuel injected (z-axis) at specific load (y-axis) and rpm (x-axis). The reason for the dip is that represents high rpm and low load. Sometimes volumetric efficiency is lower in those conditions, or fuel atomization is better, or it's tuned for fuel economy, or emissions, or it's largely ignored by the tuner, etc. The issue you describe -- hesitation or flat spot upon heavy throttle application -- points more towards enrichment settings. When you suddenly hit the throttle, the additional air in the cylinders occurs nearly instantaneously, but the fuel lags a step behind. To compensate for this, and to avoid a lean condition (your flat spot), additional fuel is momentarily added to the system until the fuel from the steady state map can catch up. It's possible that your map was overly lean in the area you increased and that conditions where you added throttle were such that you were staying in that portion of the map, but if you really are seeing it when going full throttle, then I suspect enrichment.

It's muted by default. Try clicking the speaker icon on the top right.

Under bonnet temps are pretty extreme for PLA or even PETG. Some of the major filament makers provide data sheets that include max temp ratings (claims?) before softening that are often helpful in filament selection. There are also some good YouTube channels that regularly test filaments to separate those claims from reality. If you haven't found this one, I highly recommend it. He has a PhD in Mechanical Engineering and teaches at the University of Budapest. His filament testing procedure reflects this background. https://www.youtube.com/@MyTechFun

@fastg what filament did you use for the pulley?

This forum has been strangely quiet given the number of people who 3D print, so let's start a thread for people to show their favorite print(s) they've made that's related to their passion for se7ens. The print doesn't need to be something you personally designed but should be a car part, tool, artwork or other related item you have printed. That means no searching on sites like Thingiverse and posting a bunch of things you think are interesting but have never tried. We can have a separate thread for that. Hopefully the items shown will give people ideas for their own projects. -John

If you fabricated it, then yes. If you bought it, then no. From the forum descriptions.

I moved this to General. The Fabrication section is for...fabrication.

What I did assumes you will find the correct wires, a suitable mounting place for the relay, and then make all the connections. I did a major rewire of my dash loom so where I placed the relay won't be applicable to your car. If you aren't comfortable with automotive wiring, then this might not be the best thing to undertake. It would be a fiddly job with the scuttle in place and requires you to trace and confirm wires to ensure you have the right ones. That said, I often do things that I have no right doing, and I haven't killed myself...yet. If you aren't familiar with how a standard 4 or 5 pole automotive relay works, it's worthwhile doing a quick search. There are a number of youtube videos that dig into it and make it clear. I wired mine with a standard 4-pole normally closed automotive relay available at any auto parts store or Amazon. It's nothing special. You could also do it with a 5 pole (change-over) relay. As you watch the videos, remember that the coil is operated by the side lights, and it should make sense. In my case pins are as follows 30 - switched 12v+ (controlled by ignition key) 87 - wire to DRL 12v+ 86 - sidelight 12v+ 85 - ground Because the relay is normally closed rather than normally open, power flows between 30 and 87 to the DRLs when the ignition is on. When the headlights are switched to position 1 or 2, power to the sidelight operates the coil and breaks the connection between 30 and 87 and the DRLs switch off. You certainly don't need to do this now, but you don't want to connect the red and green wires in the headlight bowl unless you cut the red wire where you would wire in the relay. Otherwise, the DRL will come on with your headlights.

The relay is set up so that when the ignition is on, the DRL gets power and turns on. When the headlights are turned to position 1 (side lights only) or 2 (side lights + headlights) the relay changes from closed to open and turns off the DRLs. This is how many (most?) modern cars are set up. I seem to recall Canada even requires this functionality in new cars. The rationale for turning off the DRLs with the headlights is to avoid blinding someone at night. In your case, with the DRL in the headlight housing, if they are sufficiently bright to be effective in the daylight, they are probably adding enough output to your low beams to blind, or at least annoy, an oncoming driver.

Are these the factory LEDs or another brand? Side light is British for parking light. For my standalone DRLs, I used a normally closed relay that feeds the DRLs from a switched 12v+ and powered the coil from the sidelights so that when they are on (including when the headlights are on) the relay turns off the DRLs. I did this during a major scuttle-off rewiring project so can't tell you exactly where to splice into those wires. I would repurpose the red wire as you describe provided there is no side light functionality in the new LED. For the turn signal, I'd run a new wire back into the body and splice into the turn signal wire there to keep things clean. I'd also wire everything temporarily to ensure things works as expected before cutting anything.

@CBuff great tip on the Epson. Mine arrived over the weekend and worked well in testing. I wish I had this when wiring the Caterham.

That's a big chunk of weight to jettison. Yeah, you just screwed yourself

I only mention it, because if that's what it's for, it's a nice thing to have.

Is it possible it's a low oil pressure switch to trigger a dash light?