redursidae

I would appreciate more information on what was required for the swap as I intend to do the same eventually.

Thank you, Croc. No insult taken, and I appreciate verification on anything I post. I didn’t know understeer was the de facto behavior as this is the only Caterham I’ve pushed hard enough to find out, and I’m still learning how to dance with it. My expectation was that it would oversteer naturally and I would have to manage it. At Autocross I did a better job of balancing the weight, but didn’t do great every time and it showed. I’m no professional and still got much to learn. Yesterday I admittedly chucked it into a hair pin expecting Chapman’s hand to give me rotation. It’s good to know about the high speed understeer too, although that sounds like aerodynamics may be playing an effect too? Greatly appreciate you sharing your specs! Good to hear that you shim the rear as well. Are there a set of recommended shim kits? Could I bother you with sharing a picture of where you measure the ride height? I thought I measured it at the right place but every time I look I get more confused. I set it to 145mm front and 160mm rear with me in the seat, mainly because of oil pan clearance but it will be lower with 13s once I eventually do that.

Took the Cat to get an alignment today expecting it would be bad after raising it so much. It was kinda bad with -1.2* camber and 0.45* of toe-out up front, 5* caster. Rear was -1.5* camber and 0.1 toe-in. To help eliminate understeer I asked them to set the front to -2 camber, 0 toe. Went for a quick blat and it feels better, but it still understeers when pushed hard enough. I’m going to shim it to try and get 6 or 6.5 caster and try again. Next step might be trying to stiffen the rear roll bar but I would rather not because likely that the tires have some blame in this. At any rate, I’m loving this thing .

This is a common misconception about oxygen sensors and gauges. Oxygen sensors don't read AFR, they read Lambda. Lambda doesn't change with the type of fuel, and Lambda 1 is always stoichiometric regardless of fuel. The gauge converts the Lambda reading to AFR based on a user configurable setting which is a multiplier of stoich AFR * Lambda. By default this setting tends to be 14.7AFR = Lambda 1 for the gasoline scale we are used to. As a result, an engine idling with an AFR reading of 14.7 but running E85 doesn't actually have a 14.7:1 ratio in the exhaust, but instead 9.8:1 . The sensor is reading Lambda=1 (9.8:1 for E85), but the gauge has converted it to the gasoline scale. This of course changes if you modify the scale in your gauge. @Mudder The AEM X series gauges are good and reliable. Install the oxygen sensor behind the collector of your 4-1 header. It's also a good idea to wire the controller in such a way that it doesn't heat the sensor until the engine is running to prevent condensation from damaging the sensor.

Im not saying that this is the root cause of your issue, but the TPS calibration needs redone. The TPS voltage should typically be between 0.5V and 4.5V. Outside of that range it usually means a sensor or wiring fault. You should set the 0 point to the voltage seen with the engine idling and butterflies at the resting position (4.49V for your case). Similarly for the 100 point and linearly interpolate between the two. Changing this will of course change your fueling. I have seen cars where the TPS voltage changes between drives and that’s an indication of a failing sensor or counterfeit sensor. And regarding an IAC for idle control, I personally find it to be a must for a street car. I run one with my TWM manifold similarly to what you described. The simpler method is using a PWM actuated solenoid, but for this to work the TPS has to read below the threshold set in the map. If you post of pic of the solenoid I can tell you what kind it is.

Even in the single throttle cars? I would have expected the MBE to be a VE model at least, but nothing wrong with Alpha-N as long as it has the right compensations. I'm very interested in checking out a map if anyone has one to share. I took a read through the posts and I see what you mean about something beyond the map being the cause. I'm suspicious of the TPS and MAP readings from his screenshot. It's possible he doesn't have MAP if using pure Alpha-N, but the TPS is critical and should read 0% with the engine off. Of course, that's assuming it was set to 0% when the mapping was done, in which case would explain some of the richness. I know the MBE's use load site based axis, mapping volts instead of throttle percentages, but this Pectel seems to be percent based no?

I strongly suggest a modern ECU tuned with a VE model and at the very least short term PID control of fueling. Judging by your screenshot, the Pectel is injection time based and pure Alpha-N? That’ll be rough to get consistent. Also is your TPS always at 10%? Because that’s a problem considering that’s your main sensor

Understood, and thank you. Will inspect the grounds.

Good to know. One of the original tail lights was working intermittently before, so I will start looking around there. Any idea if missing reverse and fog lights might have something to do with this? Yep, I did. The car already had an LED relay, and I also tried JAL's relay to be sure.

Good news! The fuel has stayed in the tank since the Autocross, and what was dripping didn’t smell like fuel, instead some sort of glue or residue in the underside of the aluminum shelf. Since cleaning the shelf and the tank as best I could this hasn’t returned As far as overall fuel smell, it is much better. I only smell the breather doing its job when I slosh the tank on a spirited drive and it subsides after some cruising. Decided to do an LED swap with tail lights and indicators from Just Add Lightness, and headlights from Summit Racing. The headlights leave a little bit to be desired in their beam pattern but it’s decent. The tail lights are good and bright as needed. The indicators have not worked well so far, and cause all the lights to panic! With only one indicator on, all of the car's light flash, including the gauge lights. If I turn the lights on, then the buzzer is constantly on and the indicator bulb is lit. That’s a first. I tried disconnecting the tachometer to test the theory that the telltale could be the cause, but no dice, and not really sure where to go from here. This issue only happens with the LED indicators installed. Here is a video of the behavior with only the right indicator on: Another interesting new quirk is that while driving with the lights on I can hear the buzzer and see the indicator bulb light up intermittently as I hit bumps. This is making me think there is a bad ground somewhere.

It’s always best to find a local tuner and use what they recommend. Aside from that, Haltechs do have a large number of tuners willing to support them. The 750 may be enough depending on how much IO you plan to use, but on today’s tech I would consider the Haltech S2 or a Link Monsoon/Xtreme G4X. Those have faster processors and internal datalogging. Maxx ECUs have also become very popular and are highly capable.

These are stickers. The PO put them on so I don’t know where he got them. My friends have used these before, and I got magnetic ones for the Miata here too: https://www.autocrossdigits.com/

Yesterday was the PCA Autocross and got to take the Caterham there. It was a lot of fun to play with the car. Finished 5th of 42 in raw times and 1st in class. My only complaint is that it has too much understeer from likely a combination of alignment and tires. I raised the ride height a fair amount and didn’t check the alignment after, and I kind of expected I wouldn’t like the tires from my past experience in the Miata. But it’s ok, because I had a blast. unfortunately there is still something dripping down the fuel tank, likely fuel. I wasn’t smelling fuel however, so I didn’t worry about it and haven’t had a chance to check. I’m waiting for a bead roller to arrive to finalize the cap/breather job and will take better pictures of that setup then. Met another new Caterham owner that happens to be another SVT. He intends to roadtrip with it. Seeing his car on 13s made me really want a set and also verified that clearance is a problem with the wet sump. He offered to let me borrow the wheels to test fit sometime so I’ll have to take him up on that.

Yes, will do. I haven't had a chance to drive the car yet, but this weekends autocross will be a good stress test.

Thank you @wdb . That does make sense regarding the other line at the tank being for a fuel return. The SVT doesn't have a return line or a pressure regulator*. Instead the pressure is controller by the ECU as a return-less system. *: The regulator on these systems tends to be inside the tank, but I haven't been in there or found information on it. Apparently it may not have one. I went ahead and looped the line as in John's picture. Hard to take a good picture, but the breather goes around and behind the tank up to the rollover valve, then over the filler and back down next to the tank. and capped the other line, but this doesn't feel like a permanent solution. It's a vacuum cap and I feel that's going to crack and leak. Open to suggestions as to what to use on this for a permanent fix. As a note it was definitely this other port above that was sending liquid fuel. When I removed the line it still had fuel in it, and tilting the line at the front of the car dropped more fuel out.

Thank you John! This is perfect. Then I'll go ahead and copy this system and cap the other port on the tank unless told otherwise.

My only guess as to how fuel could have made its way to the front is through slush when I last drove it, then maybe vacuum did something funny to start a siphon? But that's only a guess, I don't actually know. I filled the tank earlier this month to see how much it took and drove it to the nearest city, maybe some fuel made its way into the lines that day, but it certainly wasn't spilling over then. I agree about the tank ventilation and evap function. What's throwing me off is that my tank has two vents, one in the center and one at the filler neck. I don't know if it's ok to vent both with a rollover valve, or tee them together, or cap one while leaving the other one open.

Could you show me how yours is setup? No requirement where I live so I’m ok getting rid of it. But it’s my understanding that these came with this canister setup.

I came home yesterday to a strong smell of fuel in the house. Found the Cat spilling fuel from the EVAP canister at the front and had overflowed a catch can underneath the intake. The car had sat with half a tank of fuel since I last drove it the day prior, and the tank didn’t have pressure. This is the canister in the front corner. Hose marked is the one that was spilling fuel. There is a bottle down there that was full of fuel too. This hose in the tank is connected to the “purge tank” port in the canister. Is this the main tank’s breather? And the filler neck breather (?) is connected to the purge solenoid, which has a T going to the catch can that overflowed. It has the rollover valve near the wood pictured. Would appreciate any suggestions on what to do about this. It seems to me part of the problem is the filler breather is connected to the purge solenoid, which is normally closed, and has no connection to the engine. That’s probably a good thing in this moment as I think I would have found fuel in the manifold.

Thanks for sharing that. That verifies it is a variable system and does use cam period targets. You'll have to ask Haltech how that's supported in the firmware, and I'm very interested to know what they say about it.

Wow, now that's a very cool system I had not heard about before. Thanks. I haven't worked with these, but it is supposed to be a fully variable system, not a switched one, where one solenoid advances the period, and the other retards the period which is closer in control to a BMW S54 VANOS. From https://www.mgfcar.de/library/ENGINE_MANAGEMENT_SYSTEM_ MPi_VVC_MEMS_3.htm: That and other documents I read indicate it is variable, based on RPM and Load (either MAP or TPS). In Haltech you can select 2 solenoids for the Cam Control function, and wire them accordingly, but the part I'm not sure about is that usually these are cam phasing targets, but this VVC system is "cam period" targets? I don't know how Haltech would deal with that so you may be best asking their support line. Could you share a screenshot of the targets in the Emerald ECU?

The old hose had many small cracks. And the fixed hose installed. Much less odor after a drive although still found a wet spot at the bottom of the hose from hopefully a slightly loose clamp. We’ll see in the next drive. And in case I was feeling that the list of needs was getting shorter I found it needs new engine mounts and a fuel level sender gasket. are there any gotchas with replacing the engine mounts or will that be a straight forward process?

I'm curious what is unique about the K series VVC system? In the engines I've worked on this is normally a 2 pin solenoid, 12v on one, low side ECU control on the other, and PWM operated. How does the K series work?

Some details of the radiator replacement in case it helps others. Initially the car had this setup. Older K series radiator: there was a tee between the header tank and the radiator between the fan switch and upper radiator hose. The line goes to the back of the head to a plastic manifold where it joins the upper radiator hose. The new radiator was missing the provision for this tee portion, and with approval from Josh I deleted it and ran only the line from the back of the engine The next hurdle was mounting the fan. Josh indicated it seemed to have the older mounting solution, with short legs in the fan and I needed extensions and some new bolts and nylocs. Easy enough. the extensions look like so, and after cutting/filing the boss at the right side all fit together. Then used some M6x1.0 12mm long bolts with M6 nylocs to get it fastened. Need to go test drive this new setup but I don’t see why it would have any issue. Im expecting a replacement filler hose to arrive today to hopefully fix the fuel leak!

Thank you all for the comments and ear-candy! Officially it has an LSD by the "goose it and find out" method. I went out on a drive yesterday to test the fan install and make sure the coolant level was good. The fan extensions hadn't arrived, but because I wanted to take it to Cars and Coffee with friends today I ended up using zip-ties like it gets done on oil coolers. Held up well yesterday and today. Also no drama with the radiator, and the oil pressure has continued to hold up with the fresh Amsoil. But I did shake a few gremlins loose, and it seems to have a fuel leak near the tank. From what I can tell it seems to be the filler hose is cracked, so I'll work on that this week. Also found out the fuel pump is on the side of the tank? That's a first for me. Signed up for autocross on April 18th. By then I'm planning to re-adjust the ride-height to have the proper rake, verify the corner balance, do a bolt-check and fix that fuel leak. The car seems happy otherwise. @Austin David The CFO approves of my plans, but it has to wait due to the engine build in the Miata still taking place. I want to keep a fun car drivable as much as possible too. I've been sold on ITBs for a long time, and have owned an ITB car for a few years now, so yes it's only a matter of time on this one. Thanks for sharing the audio clips. I know videos rarely do justice to these induction noises at part throttle, but I do enjoy hearing the differences as the RPMs and throttle angles change. Noted on the CAN gauges. I run a CANChecked in the Miata's dash (replaces the dummy oil pressure gauge) that is feed by the Link G4X. I'm a big fan of it as well because it fits cleanly and shows all the information I need. Once a standalone gets installed it will go with a CAN gauge as well. That is glorious! Thanks for sharing. I missed out on these unfortunately. That's ok, I'll keep looking. Very nice! I've seen this video before and really enjoyed it. Cool to know you're around here. Is your steering as heavy as he says?