2.3 were shafted, but not the 2.0 units, though in Caterham application the shafts in the 2.3 are deleted making them similar to the 2.3 engine used in the Ranger.
The mapping I referred too is when the idle data is 'just' unstable enough to set up a vibration and the map isn't fine enough to give a pure idle.
Natutally alternators will be balanced when built too so could easily cause this
Is the vibration still present when you hold the clutch in?
I will check the alternator. Will have to be tomorrow, work got out of control today and I didn't find spare time.
Yes, the vibration is identical irrespective of clutch position.
SV VVC 170 - 170.4 bhp @ 7100 rpm - 142.4 ft.lb. @ 4900 rpm
Just thinking assuming the exhaust only has a single mount is this a rigid or rubber mount at the rear of the silencer.
There aren't many places where the powertrain comes into contact with the chassis - this is one though, might there be some tension in the exhaust system?
Just a quick report back on alternator. I removed the belt at the tensioner - interestingly that bolt itself wasn't very tight, its opposite thread to normal, when I exerted anticlockwise force to reduce tension on the belt and slip it off the tensioner pulley, there was an easy ability for me to tighten the bolt further, so I did.
The alternator itself rotates smoothly and with no spring back, so it seems ok.
7Wonders - the exhaust is mounted on a singerrear rubber bobbin, standard Caterham item. My old K series had a forward mount point too, but this has only one. The bobbin is working correctly and damping as it should. To truly test this i could whip off the silencer and fire it up, but I will frighten the neighbours...
Seeing as the engine when running is really vibrating like mad and the exhaust is not, I feel that at this stage I don't need to do that.
My problem is the way in which the engine itself is running, at whatever rev range or load, irrespective of clutch, so we can take the gearbox out of the equation.
Its going back to BookaTrack tomorrow and they have it for a week or so to do further tests.
I am pretty sure that there are some Duratec experts on here, that do this kind of thing as a business. Any ideas I can pass on to BaT beyond what has been discussed on this thread to date would be very much appreciated.
Out of interest I thought the maps in standard cars (which mine is) were locked. When I spoke to Troy at NMS he suggested that an early upgrade would be to replace to locked MBE ECU with an unlocked one.
I know that others have been supplied with ECUs with the wrong map flashed to them. Now my car does drive pretty well apart from the mega vibrations. I wonder whether a tweak to the map (or even checking of) would be possible by the Caterham franchise dealer?
Can i throw in my experience, such as its worth.
My day car had a new cat fitted.
Driving the car home felt as though someone had change the engine to a sports model.
The car appeared to be much more responsive, sounded sporty when faster? with a lot of feed back and vibration through steering wheel, gear stick.
After a few days i became tired of the noise and vibrations, took the car back to find that the cat was touching the heat shield, my old car was back!
I removed the belt at the tensioner - interestingly that bolt itself wasn't very tight
While the belt was off, did you also check that the tensioner pulley itself operated smoothly? It spins at a similar speed to the alt (maybe even faster). Also, I'm surprised the bolt wasn't tight as IME they're usually very tight.
Here's hoping Bat/CC can resolve things quickly.
There are smart 'phone apps which claim to analyse *vibrations. That should make it possible to compare engines etc, even remotely. And the frequency spectrum might give a clue, as in Andrew's thoughts.
* Careful with that search, Eugene.
I dropped my car off at BaT yesterday evening and when there I tested another 420R - not driven, there was no time, but with both cars side by side, both cars from a cold start, I used an expensive (£3.99) iPhone App and rested the phone on the cam cover, back of phone flat to cover, phone oriented north-south along the longitudinal direction of the car and engine. Same location on both cars.
X is the deflection left right
Y is the deflection in the same plane top bottom (of phone) i.e. north-south longitudinal to car.
Z is the deflection up down
Both tests were within 30 secs of starting the engines (I trailered my car and pushed it next to the other). Idle will have been set differently. All other test conditions were identical.
Image 1, My car time series:
Image 2, the other car, time series:
Image 3, my car frequency graph:
Image 4, the other car frequency graph: