Project Dollywobbler's Invacar - Ongoing

[dollywobbler]

The service manual reckons top speed is 60mph at 4000rpm. There is no limiter other than the lack of enough power. It sounds seriously frenetic by 65!

[SiC]

So 5333rpm at 80mph if the pulley is at max range. Plausible I guess if it has enough power to or down a hill. I guess around 6k rpm will be around its natural limit.

 

4666rpm at 70mph. Not that you would want to take it on a motorway...

[LightBulbFun]

thanks for the explanation

 

but what im trying to get at is, I know after a CVT runs out of ratio the engine RPM will start to increase (ie it stops CVTing if that makes sense) so i was thinking if it stops CVTing at 45Mph so it must increase engine revs to go faster then it must be going at quite the rate by top speed

 

I see DW has posted that info while I was writing this up

 

im also curious what RPM the transmission holds the engine at normally? (if its 4K RPM at 60Mph and CVTing stops at 45Mph id guess it would hold the RPM at about 2500-3000RPM? doing some quick maths shows 2997RPM so i think i guessed right  I realised going by what SIC just posted I could divide 4000 by 60 and get the Ratio? is that the right word im not sure, which is 66.6 and then do 66.6x45 which should give me the engine RPM at 45Mph I think... ) im also curious while reading the shop manual thingy for the transmission it mentioned there where 2 types of pulley setup I wonder which the invacar has?

 

(for those reading this sorry if its a little disjointed there where a couple replies with new info posted while I was in the middle of typing this up LOL)

 

EDIT: this all fairly new stuff to me so its quite fun and exciting to figure it all out 

[SiC]

There are ratios but of course it's not as simple as that. Min ratio, max ratio and then somewhere in-between. So until the pulley is at max extension it could be anywhere in between. Many CVT systems vary the pulleys based on engine load. I don't think the Invacar setup has anything that can do this by anyway of sensing the load directly (e.g. intake vacuum pressure). I think the Invacar mostly varies the ratio based on engine speed? DW would be able to confirm.

 

Remember these things were only really meant to be tootling around at like 20mph-30mph!

[LightBulbFun]

interesting yeah its interesting to note that the max ratio of 66.6 is the same as the Bus speed in Mhz of many Macintosh (and PC) computers from 1997-1999 go figure that one out 

 

so correct if im wrong, if we know the engine RPM stays constant? until 45Mph and we know engine RPM at 45Mph is 3K RPM then that tells us the CVT keeps the engine at 3K RPM throughout its ratio range right (ie from 0-45mph)?

 

(does anyone have a data sheet or figures for the steyr puch engine it would be interesting to see if thats the peak torque or Peak horse power RPM?)

 

sorry if this is a bit weird, its just if theres something im passionate about I like to figure out all the details 

[dollywobbler]

3000 seems about right, though she does still bog a bit on hills. Steep hills. Maybe they weren't meant to climb hills...

 

There are two pulleys, each controlled separately. Centrifugal force causes one to open up (connected to the wheels) and one to close up (attached to the engine). I guess the pulley diameter is also controlled by tension on the belt to a certain extent. 

[dollywobbler]

Also, seeing as TWC will soon be meeting The Public again, I decided she really should have an internal wash.

 

Naturally, it now looks like it will rain...

[MorrisItalSLX]

An internal wash! About time!

 

Is it now time to move on to the cosmetic work?

[LightBulbFun]

very cool, we need some interior glamour shots now

 

An internal wash! About time!

 

Is it now time to move on to the cosmetic work?

 

new headlight trim rings at long last?! 

[MorrisItalSLX]

new headlight trim rings at long last?! 

 

And hubcaps!

[dollywobbler]

No. None of those things. Well, I'm not ruling out hubcaps if I can find some. I have gently tried removing a headlamp trim and it liked being there thank you very much.

[vulgalour]

The only cosmetic enhancement that TWK needs is a bobble hat with a football patch sewn on.

[Floatylight]

I used to love the CVT I had in my A6 2,4 Avant, used to whop up to 5k and hurtle itself down motorway slip roads and the 6 speed manual select worked brilliantly. Oh for the old days (but not the fuel bills)

 

Sent from my Moto G (5) using Tapatalk

[Noel Tidybeard]

some cvts work different to others- a jizz hybrid in eco mode with make reasonable progres without going over 2000rpm!

 

a 2.0 primera will do most normal driving at around 2500- 3000 revs with 4500 revs making brisk progress- but if you floor it with it set in "manual" mode it will rev up and "change gear" just below the red line

 

the 2.0 nissan engine makes a "better" sound when you nail it than the 1.3/1.4 honda engine and bizzarely an invacar makes quiet a decent sound when being spanked!

 

one thing above all else is the smooth linea acceleration is excellent with none of the seesaw nodding dog behavior of gear changing!

[SiC]

some cvts work different to others- a jizz hybrid in eco mode with make reasonable progres without going over 2000rpm!

 

a 2.0 primera will do most normal driving at around 2500- 3000 revs with 4500 revs making brisk progress- but if you floor it with it set in "manual" mode it will rev up and "change gear" just below the red line

 

the 2.0 nissan engine makes a "better" sound when you nail it than the 1.3/1.4 honda engine and bizzarely an invacar makes quiet a decent sound when being spanked!

 

one thing above all else is the smooth linea acceleration is excellent with none of the seesaw nodding dog behavior of gear changing!

You ought to try a DSG then. The changes are so quick that you barely notice them. Same with most modern slush autos. The TC absorbs any shock from the changes, so they're completely seamless.

 

It's just old fashioned peasant manual boxes that rely on the operator to make a smooth change. Unfortunately most operators just aren't that good at it.

[Eddie Honda]

CVT is for winners.

[SiC]

Where abouts is this going to be shown at the NEC? In the new extra hall they're putting in?

[dollywobbler]

Where abouts is this going to be shown at the NEC? In the new extra hall they're putting in?

 

No. On the Classics World stand in Hall One. Next to Octane magazine...

[SierraMikeHotel]

I've driven several rental Yarii with CVT. It is weird to begin with because it's not what you're used to, but when you've got over that it actually makes perfect sense. There's no reason why a modern auto should be limited to a number of ratios when it could be at the "right" ratio all the time.

 

Having said that, you really don't feel the gears shift in a modern auto so there's probably not much to choose between them these days. Mrs H has a modern C class with nine, yes nine, so it's probably in the right ratio most of the time...

[wuvvum]

Why the actual fuck do you need nine gears in a family saloon car?  I can understand it in a 44-tonne artic, but my C class has 5 gears and I've never once found myself saying "you know what, this could really do with an extra two gears between 3rd and 4th".  Or does the emissions crap on new diesels mean that the engine only makes any power between 2,000 and 2,050 rpm so you need an endless supply of gears to keep it in the power band?

[SierraMikeHotel]

I'm advised by a shiter (can't remember who) that it's to do with emissions - the more often it's in the correct gear for the speed, the lower the output of nasties.

 

It honestly doesn't feel any different from the old one which only had seven.

[Noel Tidybeard]

back in the late 80's leylandii trucks were experimenting with cvt on prolly 17t rigids and found a cvt truck with about 140 hp would out perform a 180 hp wagon in both speed & economy!

[Sir Snipes]

So 5333rpm at 80mph if the pulley is at max range. Plausible I guess if it has enough power to or down a hill. I guess around 6k rpm will be around its natural limit.

 

4666rpm at 70mph. Not that you would want to take it on a motorway...

Sounds like the gearing of my C4....

[Talbot]

Here seems as good a place as any to put it... DW: point of order on your most recent U-Toob video, in reference to the bit about the driven pulley (pulley no.2 in your description) being on a chain drive "arm" which has an adjuster on it, to adjust the tension.

 

That adjuster (the one visible between the chain drive arm and the body of the gearbox) does not adjust belt tension. Belt tension is maintained with the eternal battle between the centripital advance in the driver pulley (No. 1) and the springs in the driven pulley (No. 2).

 

What that adjuster does is ensure that you have the correct spacing between the pulleys to ensure you get full range on them both. By bringing the pulleys closer together, you risk the belt going "too high" on one of the pulleys and potentially coming off. By moving the pulleys further apart, you then limit the available range of the belt movement on them, as with one pulley bottomed out, the other may not be at the top of it's range of movement.

 

If you've fitted a slightly longer belt, the pulleys may need to be spaced slightly further apart to ensure the belt doesn't ride up too high on either pulley. And vice-versa.

 

Don't adjust it hoping to improve belt tension!

[Hawkeyethenoo]

No. On the Classics World stand in Hall One. Next to Octane magazine...

 

If you're driving it there, can I suggest you use ear defenders and even if you're not, can I suggest ear defenders. Enjoying the videos. Ride safe.

[dollywobbler]

Here seems as good a place as any to put it... DW: point of order on your most recent U-Toob video, in reference to the bit about the driven pulley (pulley no.2 in your description) being on a chain drive "arm" which has an adjuster on it, to adjust the tension.

 

That adjuster (the one visible between the chain drive arm and the body of the gearbox) does not adjust belt tension. Belt tension is maintained with the eternal battle between the centripital advance in the driver pulley (No. 1) and the springs in the driven pulley (No. 2).

 

What that adjuster does is ensure that you have the correct spacing between the pulleys to ensure you get full range on them both. By bringing the pulleys closer together, you risk the belt going "too high" on one of the pulleys and potentially coming off. By moving the pulleys further apart, you then limit the available range of the belt movement on them, as with one pulley bottomed out, the other may not be at the top of it's range of movement.

 

If you've fitted a slightly longer belt, the pulleys may need to be spaced slightly further apart to ensure the belt doesn't ride up too high on either pulley. And vice-versa.

 

Don't adjust it hoping to improve belt tension!

 

Yeah, I'm not great at talking engineering. My understanding is your understanding, so you're still adjusting the resting tension. It was a bit loose, so there would be a jerk while that initial tension was taken up. I've adjusted it and it's now much better.

 

Anyway, DETAILING* YO.

 

* May not be detailing.

[Noel Tidybeard]

you put the indicator back on the wrong side again didnt you?

[dollywobbler]

you put the indicator back on the wrong side again didnt you?

 

No! I have actually moved it over. Then I had to re-attach the broken casing with cable ties. Classy.

[Noel Tidybeard]

ah your whoosh at the end of the video when you said it was all back together looking thru the window seems to show it on the right

[dollywobbler]

ah your whoosh at the end of the video when you said it was all back together looking thru the window seems to show it on the right

 

Filmed out of sequence...

 

Anyway, here's a rather more professional look at the Invacar.

https://www.bbc.co.uk/programmes/p06p6drv?fbclid=IwAR33HxHh83cDpmprJo7ko2OSIiMgKVvRAWQ9ahyYv8eqNT-HD__Mg9inudA