Lotus Elan: How Fast Really?

[Cyco]

A couple more Elan pics I grabbed on Sunday:

[McReis]

Originally Posted by Cyco

A couple more Elan pics I grabbed on Sunday:

That's an Elite.

[johnelliott24]

For stock cars they are the fastest. Add some wider wheels and they really go.
If you know how to work on cars then there are other cars that make equally good platforms.

[McReis]

Originally Posted by johnelliott24

For stock cars they are the fastest. Add some wider wheels and they really go.
If you know how to work on cars then there are other cars that make equally good platforms.

Wider wheels do nothing for performance. Unless you raced the Elans over swamps.

[LotusLocost]

Originally Posted by McReis

Wider wheels do nothing for performance. Unless you raced the Elans over swamps.

Depends on what you mean by "performance"...
Wider wheels gives more grip.. More grip is usaly a good thing for track "performance"..
Performance isn't just hp

[McReis]

Originally Posted by LotusLocost

Depends on what you mean by "performance"...
Wider wheels gives more grip.. More grip is usaly a good thing for track "performance"..
Performance isn't just hp

May be true. But that's not a an universal true. It depends on the grip conditions. As you know, under low grip conditions, like heavy rain or rough asphalt, wider tires do nothing for performance.

[LandQuail]

nine times out of ten, though, a car with wider wheels will be quicker around most tracks.

Big tires just spoil the car for a driver: the steering becomes heavy and dull, requiring a great deal of power assistance; the suspension must be beefed up to handle the exta weight and grip levels, and it takes more engine power to push the car forward.

However, it does translate to more outright speed usually.

Unless I'm wrong.

[greg.harvey]

I'll wade in to this one.

As a Lotus nut and a 1970s Elan owner, I can tell you that they are not slow by any stretch of the imagination. However, in modern terms, and in original trim (especially the earlier S2 which didn't have as much grunt as the "Big Valve" Sprint) they are not as quick as you might think. Handling is awesome and they feel like greased lightning, but you need to prepare yourself for getting edged at the lights by a hot Audi A3 or getting breezed past by a BMW 323 on the bypass road.

Having said that, an Elan prepared for racing is a totally different (and pretty wild) animal.

The key is engine design. Lotus made race cars first and road cars second. The result? The engines in the Elan are successfully raced "over-square" designs based on a 1600 Ford block. "Over-square" means they are wide bored with a tiny little stroke (as was the Mini Cooper, I believe). Understanding the difference between short-stroke over-square engines and longer stroke engines is key here:

(BTW, I'm not a mechanic, so if I'm not 100% right here, feel free to correct me, but the physics makes sense...)

If you have a longer stroke but a narrower piston, you get lots of momentum through the stroke, which means you get plenty of power (torque), even at low revolutions. The gain in momentum a longer stroke provides aids the take-up of the engine.

An over-square engine with a short stroke (like the Lotus block used in the Elans) has very little grunt until it gets going, and it's slower to take off because it has less help from that momentum, but its light little pistons and shorter stroke allow it to turn over (rev) much much faster (if well balanced) - perfect for racing!!

(As a side-note, a guy I drink with ocassionally went from Lotus to TVR for this very reason - he got sick of the Lotus not pulling from low revs and likes the fact that with the longer-bore TVR engine, he can put his foot down and go - no need to change down to find the power. These characteristics tend to make over-square engines better for racing and longer-bore engines better for road use - or being driven by people who don't really want to "drive" ... )


Anyway, the Elan is light as a feather, so it has plenty of torque for road purposes, but the fun really starts at 4,000 rpm. If you get a Lotus Elan engine from the '60s and have it well balanced by a racing shop, with uprated carbs and a racing exhaust to help it breath, the only thing left to do is remove the rev limiter. You have just unleashed a monster! Forget 120bhp - you're now talking more like 180bhp, with minimal effort and expense and just for having the extra revs. Revs, I might add, that a longer-bored engine would not even be physically able get to.

Indeed, when the "Big Valve" engine was released in the '70s giving an extra 10bhp or so to the later Elans, many Lotus purists at the time and now said it was a marketing scam. They point to the very fact the '60s Elan engine is already capable of producing a helluvalot more than 10bhp over the 120bhp factory rating, with minimal effort. Lotus quite rightly countered with "yes, but how long do you think your engine will last, huh?!" A fair point. Unleashing the monster in the Elan does nothing for the longevity of the engine, but what the hey. If you can afford to race an Elan, you're not going to be too upset by the engine rebuild bill once a season.

Now, bear in mind that a lot of the modern cars have a longer stroke, not necessarily ideal for racing, and because of all the electronics and crap it's difficult to get a lot more out of them than comes as standard, without having a factory team in your corner, it is no longer surprising a 1965 Elan S2 can still leave them standing!

G

Ps - I'm not surprised a well set-up Mini beat him either. I've stood at Donnington Park and watched an original Mini Cooper S in racing trim wipe the floor with a fistful of American muscle cars, not to mention Alfas, Triumphs, Austins and other quick classics. A well set-up Cooper on a twisty circuit is QUICK!!! It also benefits from the same engine design advantages.

[McReis]

Great post!

[greg.harvey]

Thanks!

[CdocZ]

Wow, that post was solid gold. It makes sense, and allowed me to understand a concept that I never really even thought about directly, and only rarely indirectly. That was awesome! Do tell more?

[henk4]

Originally Posted by greg.harvey

"Over-square" means they are wide bored with a tiny little stroke (as was the Mini Cooper, I believe).

Just to add a little on the minis, there was one "Short Stroke Mini", based on the 1071 cc, which used parts of the Formula III BMC engine, but for homologation purposes short stroked to 970 cc displacement. It produced 65 bhp at 6500 bhp, not bad for a ohv engine, and it was known as the "screamer". (borexstroke was 70.6mmX61.91mm) The 1300 Cooper S, had 77 bhp at 5900 rev had the same bore of 70.6mm but stroke was 81.33 mm. More revealing are the torque figures, where the screamer only had 76 NM at 3,500 revs, while the long stroke 1275cc engine 110.6 NM at 3000 revs.

The screamer is the rarest of all mini coopers, with only officially 963 built, 37 short of the 1000 required for homologation in the under 1-litre class.

[LotusLocost]

Originally Posted by henk4

Just to add a little on the minis, there was one "Short Stroke Mini", based on the 1071 cc, which used parts of the Formula III BMC engine, but for homologation purposes short stroked to 970 cc displacement. It produced 65 bhp at 6500 bhp, not bad for a ohv engine, and it was known as the "screamer". (borexstroke was 70.6mmX61.91mm) The 1300 Cooper S, had 77 bhp at 5900 rev had the same bore of 70.6mm but stroke was 81.33 mm. More revealing are the torque figures, where the screamer only had 76 NM at 3,500 revs, while the long stroke 1275cc engine 110.6 NM at 3000 revs.

The screamer is the rarest of all mini coopers, with only officially 963 built, 37 short of the 1000 required for homologation in the under 1-litre class.

The 999 ccm BMC Formula III engiens is/was claimed 10 have 115-120 hp to
Thats not to bad for an ohv engien from the 60's

here is one for sale I have showed it to clutch-monkey.. but he responded that I had to buy it for him... and rebuild it what a noob..
BMC F3 engien..

[henk4]

Originally Posted by LotusLocost

The 999 ccm BMC Formula III engiens is/was claimed 10 have 115-120 hp to
Thats not to bad for an ohv engien from the 60's

about the same as the Fords...I was quoting only factory figures before any further tuning...

[LotusLocost]

Originally Posted by henk4

about the same as the Fords...I was quoting only factory figures before any further tuning...

Yeah

And btw.. great post Greg! I've read it now
Nothings like a race trimmed Twink