520R SV build has commenced

[Anaximander]

1 hour ago, JohnCh said:

When I started this thread many, many months ago, I recall writing this was going to take a while.  This, however, is not quite what I had in mind.

 

-John

John, I feel your pain as I had that weird FiTech fuel injection issue where my primary O2 sensor is the passenger sensor and you have to hook up the driver's side wire harness connector to the passenger O2 for proper ECU operation and vice-versa. What your patience and thread shows all of us is that building exotic cars can at times be EXASPERATING. However, I am here to tell you that after this past weekend of my car's engine finally running perfectly, all of your hassles will be well worth it for all of the pleasure you will be getting in the near future. Trust me, it is WORTH IT! Especially as beautiful a car as you have in that exotic Caterham.

 

OTOH, I will never, ever, put a kit together with or without help, hehehe. I lack some fundamental patience when I compare my limits to some others' limits of patience. Besides, building a kit was a bucket list event and I am closing in on kicking that bucket much sooner than some of our younger members

Edited July 24, 2023 by Anaximander

[JohnCh]

@Anaximander, I saw your other post and glad to see it's sorted, and you did so well at the recent autocross.  If this turns out to be a non-issue, then I am close to tying things up.  Pop the scuttle to finish up a couple of wiring items and install the knee panels, get on the dyno, then sort registration.  How hard can that be?   

[kayentaskier]

John,

I don't know how our engines compare, mine is a stock 420, so 2.0 Duratec with Caterham dry sump; but Josh has suggested the happy place for my engine is 6.25 quarts

[JohnCh]

I have the Caterham (Raceline) dry sump system and the engine is effectively the same from an oiling standpoint.  I wish there was a definitive view on optimal capacity but it's all over the map.  I've seen references anywhere from 6-8 quarts.  Of course, what really matters is how much of the missing oil is down to combustion events vs. user error/inconsistency in filling each time.  I really hope this is simply a case that I'm an idiot.  In my favor is a long history of being an idiot. So I'm hopeful...  

[JohnCh]

I decided to attempt seating the rings today.  The plan was to vigilantly watch the Lambda reading while doing reasonably heavy throttle from 2000-5000rpm, then snap off the throttle to push the rings into the cylinder walls.  Provided there was nothing concerning in the readings, repeat a few more times.  A camera was pointed at the exhaust to record any signs of smoke.

 

It went okay.  Lambda was safe, the car sounded fine, there was zero smoke visible in the video, but…  After my last run, I noticed the oil pressure was down to 5 psi.  Oh crap.  Then suddenly it was up to about 70 psi then immediately fell to -3 psi, then up to 50psi,  then…  Clearly a sensor issue, but I decided to stop the fun and carefully drive the mile and a half to my house while keeping an eye glued on the oil pressure reading.  It did the weird stuff a couple of more times, then went to a steady reading and was fine idling and after subsequent restarting when I played with revs.  Interestingly the oil pressure alarm programmed into the AiM never came on, so it might be an issue inside that device rather than the sensor itself.  Regardless, I want to sort this before going on the dyno or have a manual gauge back up installed.  First step will be the old wire jiggle routine to make sure it's not a connection issue.

 

Although it's early days and I haven't yet had an opportunity to drive the car even reasonably hard, I do have some initial observations.  Some good, some not.

 

The car is big.  Shoulder room in the S3 has always been tight for me with a passenger.  I don’t like that and have been spoiled by the Westfield's additional 2" of cabin width, hence the reason I opted for the SV.  However, the cabin feels immense.  Yes, I'm aware I'm probably the first person to ever publicly describe any Caterham this way, but in fairness, all my tin tops have narrow cabins.  My references are a bit skewed.  

 

The seats seem comfortable enough but are unnecessarily wider than the Mogs.  This despite special ordering the narrower S3 version of the carbon fiber seats.  For me, the Westfield is the Goldilocks for seat and cabin size.  

 

The turning radius is big.  The Westfield's is significantly tighter.  The steering is also a little slow for my taste.  Not as slow as the original rack on the Westfield, but much slower than the version I've run for the past 18+ years.  The quicker Caterham rack is likely in my upgrade future.

 

Steering is very nice.  Really linear and smooth on turn in.  I've only driven 2 other cars that had that same sensation: another Caterham and a modified late 80s 911 with a lot of front suspension updates and an absence of rubber bushings.  

 

The CORE dampers are really good on abrupt bumps.  The sharp input on that initial transition is really smooth and takes the edge off the hit.    

 

So far, glare has not been an issue with the AiM display.  The custom mount appears to be doing its job.  The steering wheel buttons are similar to the Westfield's and perfectly positioned.  The wheel though is slightly bigger at 280mm vs. 270mm.  That 10mm difference is noticeable.  I prefer the smaller wheel, but it's a minor nit.

 

-John
 

[Anaximander]

John, If you need to tighten up certain parts of those seats which is what I had to do with my Kirkey style seats from Summit Racing, this product will do the trick and comes in a bunch of different thicknesses with adhesive already on the back of the super dense foam.

 

https://www.amazon.com/dp/B081PM21ZD?ref=ppx_yo2ov_dt_b_product_details&th=1

[JohnCh]

Thanks Bob, if I wasn't able to get Caterham to agree to the seat switch, I would have needed to do something like that.  However, although the seats are a little looser than I'd prefer, it's not to the degree that a correction is required.  

[KnifeySpoony]

I'm slim and pretty much have to wedge myself into the s3 carbon seats. I wonder if you actually have sv seats? Have you measured? 

[JohnCh]

Yes, they are definitely the S3 version; labeled and measured.  The difference in width to the Mogs is slight, but noticeable to me.  I wouldn't characterize the seats as loose, but they are not quite as snug as the Mogs which are similar to the older R500 seats in this regard.  I'm not sure anyone else would notice the difference, but there is a subtle reminder for me each time I get in the car.  With the Mogs, the fastest entry is done with one hip pointing slightly downward, then rotating my hips once it passes the lap belt.  Sitting with both hips level results in the belts being caught between my hips and seat and often wedging in place.  With the Caterham's seats, I can sit straight down without this happening.  Yes, the belts touch my hips, but it's not tight enough to pull them down.  I haven't measured but I suspect there is a very slight difference between the two in this area.  Maybe 3-5mm?  By contrast the SV seats have noticeable gaps between my hips and the sides.  The photo below shows the differences between the two versions of the carbon fiber seats.  Tillet didn't provide a measured drawing of the R500 seats, but he did provide the following about the differences:

 

"The original Caterham R500 seat was not made for a crash helmet or Hans device so when we made the 620R seat we moved the headrest back ¾ of an inch and lifted the belt holes.

The inner shape of the 620R/ B6 is very slightly larger and the lack of side carpet also give a little more room. The B6 620R version is more symmetrical in the seating area and has a carbon top layer facing forward only. The R500 seat has an epoxy carbon Kevlar front and rear surface, with a black vinyl glass base moulding.

 

The base frame of the 620 R seat is handed and tipped in towards the centre to give a better driving position with the shoulders inside the car. Nothing that cannot be done to the R500 seat with two 8 mm spacers under the outside runners."

 

 

-John

[KnifeySpoony]

Oh ok, I had assumed you were loose in the seat. You're talking 3mm, just wear slightly thicker trousers... 

[JohnCh]

It wasn't a complaint.  it was an observation.  

[JohnCh]

For the heck of it, I measured the width differences between the Tillets and Mogs.  It's about 10mm at the hips and 20mm further forward about the location of the crotch strap cutout.  Bigger than my estimation above which explains why I notice it, but again, not a massive difference.  

 

I also tried the car again, repeating the ring seating process to see if I could replicate the weird oil pressure readings from yesterday.  Nothing.  Oil pressure read perfectly normally during the entire drive.  Intermittent electrical issues are such a pain.  I'm hoping this was some really weird anomaly that doesn't reappear so I can proceed with the dyno session.

[sf4018]

I had the exact same symptoms for oil pressure. Ended up being an intermittent loose ground wire somewhere on the engine harness. Swapping out the harness also fixed a weird issue with bogging down on track on occasion.

[JohnCh]

Thanks, was this something that happened with increasing frequency or was it just random and occasional?  I think I'll pull the scuttle this weekend to finish up a few jobs in preparation for the dyno and registration and see if jiggling that ground connection to the AiM does anything.  The ground for that circuit has two connections I introduced: the connection to the Binder plug for the AiM harness and the connection from the factory gauge harness to the 24 gauge wire required by the Binder plug.  I'll also check the sensor connector and pin into the ECU connector. 

 

 

 

[Anaximander]

John,

 

For some, 10mm or almost half and inch is no big deal. However, for some of us, it does not give us that snug "locked in" feeling that we need to feel comfortable slinging the car around and dealing with centripetal forces. You might want to try some of that dense closed cell foam with the stickum' backing in key critical areas and see if it makes you feel more locked in on the driver's seat. I did just that on my Summit racing seats and the lateral motion I was experiencing in the seat while autocrossing has been significantly reduced. It is always a trial and error effort but I think well worth it given that I was able to use the patterns of the existing seat covers that were designed for the seats and tightened myself around my upper back which was critical for feeling more "locked" in place.

[JohnCh]

Thanks Bob.  Once I have a chance to drive the car hard, I can determine if the seats are too loose and require additional padding.  My guess is they are just fine.  A little looser than I prefer and not as optimal for me as the Mogs, but more than good enough.  The dyno is scheduled the week of the 14th, with the alignment hopefully happening around that same time.  Once those two things occur, I should be in a position to better evaluate all aspects of the car.  

[JohnCh]

In preparation for the dyno, I took care of some things I previously punted for various reasons.  The big one was soldering in the pull-up resistor for the oil temperature sensor so the AiM could read it correctly.  That necessitated removing the scuttle, which is very easy to do after the conversion from rivets to rivnuts with M4 fasteners -- highly recommended mod.   The AiM now reads about 9 degrees cool at room temperature.  Once I run the car again, I'll check accuracy at running temps and adjust the calibration accordingly.  I had also planned to install the remote button interface for the AiM which provides a dedicated button to reset the trip odometer.  However, when attempting to install it, I discovered my mount for the AiM makes that a difficult process.  When doing the original design, I had incorrectly assumed this was a push in fitting.  It turns out it's screw in.  With insufficient finger space, I was faced with removing the rear mount, or punting again and doing this as a winter project which includes printing a slightly redesigned rear mount.  I've gone with option two.  That means rather than resetting the trip odometer with a single push of the button on the steering wheel, I need to go through a couple of menus on the display.  Not a huge inconvenience.  I also ran power to the 12V outlet attached to the glove box and confirmed the on/off switch is doing its job to stop parasitic drain from the USB adapter. 

The knee trim panels finally went in, with the driver's side first drilled to mount the data port for the AiM.  

 

 

The Element fire extinguisher was installed above the passenger footwell.  Easy to reach, but not in a location that screams "steal me!"

 

 

Next was adjusting the throttle pedal stop and putting silicone on the throttle cable ferule where it mounts in the top of the accelerator pedal.  A close look revealed that at full throttle, the rough, sharp edge of the cable cutout pushes into the cable.  That seems like an eventual break point.  A few minutes with a small file rounded over the edge.   

 

 

I also attached the cover I printed to plug the hole for the cylinder head temperature sensor Ford uses in most applications of the Duratec.  Without this plug, water can fill the void that leads to the top of the spark plug ports for #2 and #3.  The 420 uses a valve cover that doesn't have this opening.  I've never seen it on a US car so perhaps it's a European fitment.  Does anyone know the source, or if Caterham has these modified? 

 

 

Finally, I did some general clean up: removed last vestiges of blue tape, cut off the ends of any zip ties I missed earlier and sealed a couple of unneeded holes in the firewall with rubber grommets.  Next step is the dyno on the 14th-16th, followed by an alignment, and (hopefully) registration.  If things go well, my 420R garage sale is just around the corner.

 

-John

[JohnCh]

I pinged Caterham about a 22% rack for the SV since I didn't see one listed on their web store.  I'm sure their answer isn't new information for a lot of people, but it was to me:  "we only offer a 22% for non SV cars as the steering rack body is different on an SV."

 

-John

[JohnCh]

I had my appointment with SBD on Wednesday.  Steve was helpful but unfortunately he was having connectivity issues on his side that impacted some of the session.  However, I did get some questions answered and some changes made to the map.   

 

The ECU now controls my heated seats.  I haven't yet confirmed they work, but according to the ECU it is switching the relay when the engine is running.  Idle speed has also been adjusted from the as-delivered setting of 1200rpm to a calmer 1000rpm once operating temperature is reached.  He also showed me some shortcuts, that sadly I have already forgotten. 

 

When looking at the really rapid TPS spikes I mentioned previously, he posited it's noise from the TPS.  The speed site changes were following the changes in TPS voltage and were never spiking to full throttle which is what he would have expected if the sensor wiring was picking up the noise.  It doesn't appear to impact drivability but is something I'll continue to watch.  When I have time, I'll swap out the TPS for a spare and see if it's any better or worse. 

 

I put about 50 miles on the car Saturday with adaptive mapping enabled in an effort to further improve the map for the 30+ mile drive to the dyno this morning.  That drive went well.  It will stay at the dyno facility for a few days to dial things in.  The hope is that it will be ready for pick up on Thursday morning, then it's off to Beachman Racing Friday morning for the alignment and to get the list of things I did wrong during the build. 

 

After dropping off the car at the dyno, I Ubered to a licensing office in that same city said to be familiar with the registration process.  They were.  In about 10 minutes I had plates! 

 

-John  

 

[11Budlite]

Nice, congrats John!! I'll be interested to hear how the dyno session goes.