'Cruising' speed

[HQentity]

Hiya all!

Now obviously this will vary not only with model, o/d non o/d, manual or automatic, well pretty much everything I suppose!

The question I'm asking is, how fast do you go? How fast CAN you go before bits start falling off? (of the car I mean!)

Personally I don't have a speedo, but I tend to stick to 3000 revs in 4th which I believe is about 57-60. I went downhill once which got her up to about 70, but I think theres a reason she doesn't have overdrive!

[Toledo Man]

Your 1850 should be able to keep up with modern traffic. Motorway driving will be a bit harsh without overdrive. Overdrive boxes are getting hard to come by these days so you could fit a modern 5 speed such as the Ford type 9. Rebushing the suspension and front subframe will also make a big difference.

[HQentity]

Oh I'm sure she's more than capable! I just feel a little mean! She's a solid old bird though! I was just curious what other people set as their 'norm' so to speak

[Henk]

Just returned from a trip to family in France. Around 2500 km's in one week. On motorway cruising at 4000 rpm in 4th with OD on 185/60R13 meant 130~135 km/h (GPS nav measuring).

[Karlos]

Every weekend I do 70 on the M23 between Gatwick and K2. A lot of people drive at about 67mph in the middle lane which annoys me as it is neither the speed limit nor significantly fast enough to avoid me having to push on in the outside lane to get past. Often these people will speed up when someone starts toovertake and then slow down again if you give up on the overtake.
At 70 Mph the car feels fine and holds its own though with enough power in reserve for long hills etc. I think it could happily sit at 70 all day.

[Mahesh]

I remember an 1850 with no overdrive in the mid 70's used to go up to Blackpool and come back at over 90 and then some.

My Sprint used to go up to *22 on the speedo very easily, nowadays 70 cruise to and from Stoneleigh, but then it needs some more work done.

Can't be more specific on a Internet forum, memory is not that great,

[cliftyhanger]

When I did the last RBRR in a friends TR7 powered 1850, sprint od box and axle, it cruised very very happily at 85mph. My friend is American, so wasn't too worried about points....besides, that was on vast stretches of empty motorways.

My Toledo has the same setup, I "suspect" it is equally capable as the AMericans car. Both would cruise at 100 with few issues except fuel consumption!

[Carledo]

The Carledo pulls a ton at a mere 4500 RPM in 5th gear (on a track of course )

But the difference between 100mph cruise and 80mph cruise is upward of 10mpg not to mention the possible damage to ones licence so I tend to settle for 80 @ 3200rpm.

Steve

[MIG Wielder]

My 1850 will cruise at 70 all day with some in reserve for getting past the dawdlers. It does have overdrive though which makes for a more relaxed rpm.
Tony.

[Mahesh]

Excellent, mph or kph best not to list,

[Jon Tilson]

Fit ohc dolomites are quite capable of doing the continental....130 kph all the way to the south of france. Without o-d you just
pay a bit more in fuel.

Ohv cars aren't....odd bursts yes but all day with no oil cooler and its a bottom end rebuild.

Makes you wonder where the progress has really been in the automotive industry. I guess its all in crash safety and fripperies...
then there's always a P6 which shows not much in crash safety either.

Until the tesla came along the industry has stagnated....

Jonners

[captain_70s]

I always found my 1300 was far nicer below 50mph, but mine is fairly knackered in the engine dept. I did once sit at 70ish with my foot glued to the floor on the dual carriageway south of Aberdeen, it was doing some serious rpm though and the blue smog cloud was embarrassing... It'd do an indicated 80mph, in theory of course. I'd never go that fast...

The 1850 would happily sit at 60-65mph but a sustained 70 was a bit busy for my liking with no overdrive. Even my modern Honda sits at 3,450 at 70mph in top though, just the same as the 1850! At 50-55mph on my A-road commute it would also give a steady 35-40mpg! It'd do an indicated 95mph, in theory of course. I'd never go that fast...

[HQentity]

Wow i had no idea she would be okay at those kind of speeds! i never thought it was worth taking the chance! I guess I'll see what happens today and push her a little more than usual!

[cliftyhanger]

The problem I "think" is that our old cars are noisy compared to modern stuff. So a dolly at 4000rpm sounds so loud compared to the cosseted cabin of a newish car. And then we think the dolomite will fall apart! But it won't (or shouldn't if screwed together properly, but that is a different issue). The situation is sometimes made worse by fitting "sports exhausts" which seem to offer a very smll power gain in return for sore ears on the motorway. Strangely the 2sports" exhaust on my TR7 toledo is not bad, but my spitfire is dreadfully boomy on a 4000rpm+cruise down the M40. A job for next winter.

I think the noise is also to blame for people wanting to fit longer ratio diffs so the engine doesn't rev so much. I am not convinced this is good, the factory tended to get this right, and took into account all the gearing. Not only that, often it doesn't help economy, as the engine struggles a little to pull the car along (kipping found this out through extensive research) and overdrive is the best solution. Or a 5 speed box....

[cliftyhanger]

The Carledo pulls a ton at a mere 4500 RPM in 5th gear (on a track of course )

But the difference between 100mph cruise and 80mph cruise is upward of 10mpg not to mention the possible damage to ones licence so I tend to settle for 80 @ 3200rpm.

Steve

On the 10CR we sat at 110mph (satnav indicated, autobahn) and I can swear I could see the fuel gauge move drop to 100mph and it seemed to be rather better. Even a spitfire has dreadful aero!