GTIspirit

@1turbofocus I was wondering if you were still in business. This Duratec complete long block in 12:1 compression ratio seems like a great choice for a Birkin 7! https://focus-power.com/product/duratec-engine/

I know Lotus 7's are small and lightweight, but I'm really wanting to know how "it was stored in the attic of the owner’s house"......

Those crates look awfully big for such a small car!

True, quite a few of those aftermarket conversion companies were using Tesla powertrains. Motor, inverter, battery pack modules from a wrecked Tesla, which isn't a very sustainable business case. All were selling in quantities of 1, 2, 5, barely ten, so not much, but a start. Yes, the kits include an OBC. Looked like it was a Cascadia Motion unit with combined DC/DC. BMS and VCU from AEM. Yes, that AEM. Holley bought AEM. The kits also included low voltage (12V) electric cooling pumps. Here's more info on the electricGT kit for 911. Who's to say if $67k for a bolt in EV conversion kit for an old 911 is lots of money out of this world. Analog Motor Company reportedly has customers. Yes, all the companies I spoke with at SEMA said their conversion ran. But hey, it's SEMA, who really know for sure! Reminds me of the Exobusa I saw at SEMA. Closest thing to a seven. Reportedly made 800hp, but didn't have an ECU on it and the engine hadn't actually run yet. So yeah, gotta love SEMA! @Alex-Ks1 if you've got working commercial vehicles, and are ready for production drop me a PM. I'd love to hear what kind of solutions you're looking for, or what are some of your pain points or wishes.

Isn't that the philosophy of a seven? Install the powertrain of your choice? Plenty of electric vehicle conversion kits and upfitters at SEMA. (Though oddly, no seven at SEMA. ) https://www.electricgt.com/ https://legacyev.com/ https://www.ampereev.com/ https://appevsystems.com/

In case anyone is wondering what this looks like, because you're thinking hmmm, aluminum calipers, add lightness! I tried both directions for the banjo fitting. It just didn't work. A different softline to the caliper would anyhow be required for a Caterham so maybe someone could figure out a way to make this work so you can use lighter, more reliable Mk4 calipers. It can be done, the OE Mk4 flex line has a very specific angle to the line coming off the banjo bolt fitting. Something like that is required to make this work.

The parking brake self adjusters on the Mk2 Golf rear brake calipers are notoriously problematic. The tip in the VW community is to replace them with the Mk4 aluminum rear calipers, 1J0615424 and 1J0615423. They bolt right up, but the brake line routing is slightly different. Mk4 calipers also use a banjo bolt fitting, instead of a thread in fitting. I could never get the Mk4 brake calipers to work on my Mk2 because the banjo bolt fitting trapped the caliper mounting bolt. Meaning, you'd have to disconnect the lines to replace the pads. Maybe the mounting/routing is different on a Caterham so the lighter Mk4 calipers with improved parking brake self-adjusters would work on a Caterham?

No need to run it in parallel if the aftermarket wideband controller outputs a simulated binary/narrowband/switching sensor signal. The Innovate Motorsports LC-1 did this. So then you just had to connect that simulated narrowband signal to the factory ECU. The cool thing about that is the ability to bias that simulated signal to say lambda 0.9. The factory ECU would then closed loop control to that switching point, and cause your fuel consumption to increase from running at 13.2 AFR.

That's what I was looking for, something ignition, injection, or wiring related. What caused you to think the coil pack was bad, causing misfire? How was it before? If engine is still misfiring, and catalyst getting hot (or was that before you replaced the coil pack) what makes you think the coil pack fixed it? Double check the wiring, paying particular attention to the afflicted cylinders. Inspect the terminal seating. I've seen terminals not fully seated which can cause intermittent contact. I've also seen bad crimping cause short circuits between terminals. Beep it out from end to end just to be sure (continuity is likely ok). Then start wiggling wires. My guess is it also happens when cold, you just don't notice it because engine isn't hot enough to cause backfire. Look for lean glitches in the data recording, as that's symptomatic of fuel not combusting, i.e. missing spark.

@Vovchandr does the combustion event behind the throttle blade only occur on cylinders #3 and #4? Never on cylinders 1 and 2? Does it only occur at idle, never when the throttle blades are open? I couldn't tell from the video, does it occur when revving up the engine and then releasing the throttle so the blades are closed? (Does this only occur when ECU thinks it's in "idle" state?) How does the engine run when cold? Does it actually run smoothly, or a bit rough? You said the coolant was always muddy, which implies the engine fine some time in the past? What was done since then? New ECU? Changed wiring? Removed and re-installed engine after some mechanical work? I'm still tending to think wiring. Maybe cylinder 3 and 4 injectors or ignition got mixed up if the engine ran fine before? Coil on plug, distributor? Make sure the wiring is absolutely correct before checking timing. Even better, get a friend to watch you check the wiring. By now you've been staring at this for a while, time to get a fresh perspective to double check things.

yes, this seems more like a backfire than a misfire. Is that flame behind the throttle valve? It almost looks like combustion happening. The only way that should be possible is if spark happens when the intake valve is open. Double check the injector and ignition wiring, and cylinder assignment. This is the number one mistake on new engine controls setups. Then, double check the ignition timing without fuel, with the starter cranking the engine. Though, if the wiring was wrong, it shouldn't just happen when the engine is hot. So you may have a few things going on, like too much fuel along with incorrect cylinder wiring.

There is a difference between misfire and backfire. A misfire will sound like an missing cylinder, and will be visible in the data as a temporary lean condition. Typical cause is injector fails to open, or ignition just doesn't take place. If you've got a lot of spark retard it could be at the burn limit. Typical backfire causes are incorrect ignition timing, incorrect injection timing, or too rich (unburnt fuel going into hot exhaust and self-igniting). Without knowing anything about your engine controls it's tough to diagnose. So ask yourself, if this only happens when hot, what changes? Is the injection timing wrong when engine is hot? If it was due to a burnt valve, why would you only get backfire when engine is hot and not all the time? Fuel pressure typically has no engine temperature dependency. Start eliminating potential problems and narrow down potential root cause. Confirm ignition timing with a timing light. Confirm air fuel ratio with a known good wideband lambda sensor. Confirm all your engine control inputs, all temps and pressures at ambient before start after engine has sat a lot time? All values plausible after engine has warmed up? (Engine temp equals thermostat value, intake pressure below ambient at idle, etc.) BTW, old VW diesels were famous for head gasket failure. The symptom was bubbling coolant, but somehow it was still always clear. I'd be pretty concerned about "muddy" coolant after several system flushes.... But this is probably a separate issue.

Ha ha! Yeah, I never checked the formula itself! Years ago I used it to try and estimate some stock spring rates for reference. It was very close to published rates for higher coil counts. For lower coil counts, i.e. four coil counts on front strut springs, it was off a bit more.

Here's an online coil spring rate calculator https://www.therangerstation.com/how-to_pages/coil_spring_rate.shtml

Slight thread highjack. What are the typical spring shock specs for a Lotus 7 / Caterham 7 / Birkin 7? What spring length, diameter, and rate? (2.5" was mentioned above, but Tom at Birkin told me 1.9" ID, which I assume is really 1.88".) Here's a good overview of all the different combinations available, Eibach Race Springs Then for shocks, what eyelet length and stroke? Seems like there should be plenty of generic formula car, or circle track options available which should work. (Circle track is great cost effective performance parts option )