First SV Test Drive...observations, any insights appreciated

[desr]

Test drove an 2016 SV for sale...first drive in a Caterham. Car has aftermarket ECU, lightened flywheel, 150+ HP claimed. Four observations made: 1. Car had difficulty idling when started. Often stalled when coasting to a stop, even after warmed up. 2. Vibration through the car up to 3000 RPM then disappeared. 3. Hot air coming through the heater when driving even when the fan motor not switched on. 4. Difficulty engaging clutch and keeping the revs high enough to avoiding stalling the car when taking off. Any perspective on these items would be appreciated.  

[Croc]

13 hours ago, desr said:

 

1. Car had difficulty idling when started. Often stalled when coasting to a stop, even after warmed up.

 

2. Vibration through the car up to 3000 RPM then disappeared.

 

3. Hot air coming through the heater when driving even when the fan motor not switched on.

 

4. Difficulty engaging clutch and keeping the revs high enough to avoiding stalling the car when taking off. Any perspective on these items would be appreciated.  

 

1. Needs a retune to fix those.

 

2. Was car rolling or not?  If rolling my first suspicion would be wheel weight.  If stationary then I would suspect an engine harmonic or more likely a flywheel balance issue.  Wonder if they milled the flywheel to be lighter or it was cast that way?

 

3.  There is a lever under the dash to close the vent.  Assume this is a Duratec engine car? 

 

4.  Lightened flywheel makes things challenging.  This is compounded for this car by having a tune issue which would have made it difficult to gauge revs needed.  

[MV8]

That it is an SV chassis doesn't say much about the specification.

 

Sounds like a Ford "Sigma" 1.6L. As Croc said, there is a heater control under the dash. This controls the heater valve that adjusts the coolant flow through the heater core. The fan is a separate function to boost air flow into the car.

 

In addition to correcting idle under various temps, I suspect the tune may also reduce vibration and make clutch engagement smoother (hopefully using a MAP sensor for load adjustment), but it would take trial and error to sort out. Not likely to be a single afternoon fix.

 

If a light flywheel was installed, a standard replacement weight flywheel can be installed to make it like a normal car but the engine must be removed to do so.  It sounds like all the issues but heater may be due to settings in the aftermarket ECU. It should also be checked out to ensure it isn't running too rich (typically in an effort to make more power) as this can shorten the life of the engine. Your tuner should understand your intended use. Drivability and efficient motoring like a "grocery getter/soccer mom" instead of maximizing power on the dyno sheet.

[desr]

Thanks for your timely response, very helpful. It is a "sigma" engine. i figured there had to be a diverter for the heater, but unsure of location. The vibrations were more pronounced when driving, and their was no vibration through the steering wheel at any time. I suspect the tune is the issue and unsure why a replacement ECU was installed. Unfortunately the owner is not available to provide some background.

[Vovchandr]

2 hours ago, desr said:

Thanks for your timely response, very helpful. It is a "sigma" engine. i figured there had to be a diverter for the heater, but unsure of location. The vibrations were more pronounced when driving, and their was no vibration through the steering wheel at any time. I suspect the tune is the issue and unsure why a replacement ECU was installed. Unfortunately the owner is not available to provide some background.

 

As I always say. When you're buying a used car you're not buying the car but buying the owner. 

 

If the car is having issues and owner is not available it's a serious consideration for you to be troubleshooting issues indefinitely and/or paying somebody to do so for you at a decent hourly rate. 

 

This is coming from somebody who's still troubleshooting mystery issues 7 years later with his. I hope the price is reflecting issues and unknowns, if not then the premium for a well sorted car is worth it. 

[Xhilr8n]

We just received a newly built 360R.  Lightened flywheel.  I’ve driven manuals of all sorts from 1950s on. Have a fav little Honda Si manual I bought new 11 years ago.  This Caterham is a real challenge on a hill, and I live near lots of steep ones including my driveway.  I think the limited slip diff has helped me not spin wheels too badly, better than clutch smell.  It’s that challenging.  The idea of the light flywheel is to let the car accelerate and decelerate better but you really miss the weighty flywheel if you just drive around in the hilly world.

 

Point is there is no tapering the clutch into a gear, it has to be decisive.  Reminds me of a girl who likes her hair pulled.

[theDreamer]

The heater control is just a simple pull/push knob. Most are located on the passenger side under the fuse panel. (see 1^st image)

It operates a shut off valve which often times sticks due to limited use. (see 2^nd image)

This causes the cable to not function as required. In my case I had to physically rotate the valve from open to closed many times before it freed up enough to where the cable would open and close it from inside the car.

[desr]

Xhilr8n, how long did it take to get used to the lightened flywheel set-up? Sounds exactly what i was experiencing. compared to my Miata, this was worlds apart. i was definitely tapering the clutch when starting up and backing up.

[Xhilr8n]

I have an even worse issue, my Honda shifts like butter, best car to learn on ever.  Our Europa 3841R could be touchy as well.  At Log Concours they asked me to move it across the parking lot in front of the Judges to see if ‘we’ could do it without a shudder.  That was a relief actually

 

My mindset is that this car is here to teach me I never really needed an easy car to pull off like a smart looking person.  I can pull her hair if she wants.

 

Seriously, like any new manual it teaches us how to shift it.  In a few outings level or near level ground no issue.  Just a matter of timing.  Other than the tiny oddly spaced pedals.  Turns out they are just about perfect but still muscle memory only came with seat time.

 

Steep hills are still scary, like first time I ever drove a manual, like the Europa.  Practicing on my steep driveway but still getting a tiny bit of wheelspin and a little clutch fragrance 😔

 

Gotta pull her hair just right, I’m getting there.

[KnifeySpoony]

Hmmm my clutch modulates very smoothly on my 420R. Very easy to engage 1st gear smoothly

[CBuff]

I have a similar experience to @KnifeySpoony. My new 420R 5 speed is relatively user friendly. Def takes some getting used to vs my BMW with longer throws. The mazda box is shorter, notchier (sp? or maybe not a real word) and the clutch engagement is much shorter. I am now used to it. I always drive with super thin soled shoes, when I forget and jump in with regular shoes, it's a bit of a mess with pedal feel. I would think with thin sole shoes and some practice, if you are still having issues should be some adjustments. 

[Xhilr8n]

I just need more seat time with her. Shifts smoothly just fine most of the time but the light flywheel and light rear end invites wheelspin.  Now I live in a very hilly area with challenges everywhere.  My driveway plenty steep.  I stop and practice on it each time but not confident yet.  Yet.

[CBuff]

Excuse to have to drive your cat more  = good problems to have.  

Edited July 29, 2025 by CBuff

[desr]

Thanks for all the perspectives. since i have been looking for one of these for a very long time, i opted to go for it and figure it out rather than keep looking for the perfect car. This one has almost everything i could ask for and its located in Canada which makes it a rare find. 

[theDreamer]

 desr, you didn’t reply to my PM so am I correct that you have purchased the 2016 that is/was in St. Albert, Alberta?

Why I ask is that I was trying to verify that this particular ad was genuine and not a scam. There were telltale signs like, two different cars pictured in the ad, selling for the estate of a dead relative and then Jacqueline was being very cagey about what info she gave me. She has since stopped communicating altogether. If you bought this car then that answers those questions.

If however you have purchased a different car please, give us the particulars. As they say; Photos or it didn’t happen.

[desr]

theDreamer, Sorry i missed the PM. I have been overwhelmingly busy with renovation projects and the SV landed right in the middle. i went out to see the car last week and drive it. i have pieced together the story based upon conversations with Jacqueline and looking through the boxes left by her uncle. I purchased the car and am now in the process of arranging shipping to Ottawa. You are in Ontario, where do you put the front plate?

 

 

[theDreamer]

Front plate? What is this front plate thing you speak of?? hehehehe

I have not made a bracket yet but several in our group, (see PM) have. I carry the plate in the map pocket so if I'm stopped I can say; here it is and it just came off...

This was Paul's first plate bracket on his SV. He has since removed it because it hung just a little to low. He is working on placing the plate about an inch higher.

[IamScotticus]

Can you have the plate digits on a vinyl wrap across the nose?

[theDreamer]

No, the only legal plate is one issued by the province. I know several people have had sticker plates made but if you get the wrong COP or one who has had a bad day it can be worse than getting dinged for no plate.
A member of the Lotus Club of Canada had specialty plates that read KEVS 7. However, I do not know if he used the real front plate, a sticker or painted on version as I do not recall seeing the car with those plates. When he sold his seven those plates went on his Europa. (see image) In Ontario, the plate is registered to the owner and do not go with the car. Chalk up one for us doing our part for recycling.
I believe this front plate was painted on. Still not legal but probably less likely to cause an officer to turn around and pursue the driver.

[Xhilr8n]

Update:  250 miles in I can arrive home with no discernible clutch aroma.  Progress.   It’d definitely getting more comfortable to zip about.