The true power of our cars

[STELL]

I'm sitting at home looking in the Automobil Revue catalog from the Geneva autoshow of 1988

Our LC engine is listed at 162HP (Din) at 6500 RPM and the HC engine is listed at 183 HP(Din) at 6500 RPM.

We have read at plenty of places that the HC was easier too drive due to different reasons then the LC. More tourqe at a wider span for example.

But now to my question.
We also know how much most car makers and espesially sportscar makers had a few "Marketing horses"

In other words ,Lets say the HC engine acctually had 170 HP instead of the stated 183 and the LC acctually had 150 hp instead of the stated 163HP

Does anyone know if any magazine ever tested the true power of the engines as they were new?
Or maybe someone here has done it to a stock engine?
I do remember from my visit at the factory in 1980 how a man in a "Doctors coat" walked among running engines that was "Broke in and tuned" at the factory. But still was the acctual power the same as the stated?


This might have been up befor, but i don't remember any thread about it

[Lotus-e-Clan]

There is more to the performance of the Excel than power figures - frontal area/aero, kerb weight, power-sapping engine ancillaries etc. all have their effect.

A 160 or 180 bhp engine dyno'ed with, and without, full ancillary options will return significantly different values for power and torque.

Contemporary perception of performance by jurnos centred on the lack of torque in the low-midrange which unfortunately for the lazy driver means at legal road speeds you need to change gear and rev the engine to keep other road-users behind you. A high revving motor in a low-frontal area/aero dynamic car might come alive above 80mph in 4th gear but feels dead 'around town' ... which is a place where low-revving high torque DIEsels are most at home.

Also bear in mind, the real world performance of relatively light weight/low powered cars like the Excel also suffers significantly when you add passengers, luggage, and PETROL! And when the Jurnos test them they tend to be in 'heavy trim' (and Jurnos are FAT! )

Since "de-ancillerizing" my engine I'd be inclined to believe the 180 bhp claims for the Excel when I compare its on road performance against cars with similar (higher and lower) BHP/ton figures. Mind you, that said, I do remember being disappointed in its performance when I first drove the car - but it was in a poor state of tune (wouldn't rev to the limiter) at the time and that was before removing power-sapping ancillaries -since then - (if the clutch isn't slipping!) I've found its performance reasonably satisfying.

[alanbell]

when i first (at circa 40k miles)put my excel se on a rolling road it recorded a disappointing 163bhp and 154ftlb. some 6 years later after mild port polishing this had improved to 170bhp and still 154ftlb, a 421 manifold improved things further to a best ever 179bhp but 4 ftlb had escaped. last year the engine blew and was rebuilt by lotus bits so the present power and torque figures are irrelevant as the engine is now 2500cc. lotus bits did say that the power and torque recorded at 40k miles was what they would expect so your estimates are pretty good.

[AJ912]

Hi Stell,

My 85 still 2.2 LC has been tweaked by increasing the compression to HC level, fitting HC carbs, head gas flowed & tubular exhaust manifold. Though not bench tested, the guy who did a lot of this said I'd probably be able to find 200bhp in a particular tuning setup, but realistically 190bhp is believable.
Injection with mapping is the only way to see a real 200bhp with all the above work.
So maybe a brand new 160bhp would be 10bhp lower.

10bhp is not much to find or lose and in reality you probably wouldn't notice. As the guys here have said a bit more torque would make more difference, hence the injection control. Even with my "new" engine I wouldn't want to sit it above 4,500rpm all day. I do prefer to keep some originality though and the Toyota gearbox is smooth enough to keep going well around town.

I went the route above because I didn't want Nicosil liners failing, Iron in 60k miles I can clean up again, I just have to let it warm up before thrashing, the piston clearence is a little bigger when cold.

[tonypoll]

I've DTA mapped ignition, but otherwise the car is a standard SE (valves, head, exhaust, carbs etc)
When getting the ignition set up the rolling road figure, from Northampton Motorsport, was 173.7 bhp at 6,500 rpm, and 162.1 lb-ft torque at 4,900 rpm.
However, rolling road figures are notorious for accuracy, so make of these numbers what you will.

[Simpatico]

No non-turbo'ed 16v Lotus engine has never felt as fast to me as contemporaries with supposedly similar outputs (2.8i Fords etc). I just put this down to marketing horsepower as stated previously

[lambert.john]

On a rolling road, recently, my bog standard SA (HC engine) recorded 166bhp @ 6000rpm and 156lbft at 4600rpm.

[Lotus-e-Clan]

On a rolling road, recently, my bog standard SA (HC engine) recorded 166bhp @ 6000rpm and 156lbft at 4600rpm.

Surely that's not bad considering age/mileage and maybe the autobox, and an SA will have fully loaded engine ancillary options!

[lambert.john]

On a rolling road, recently, my bog standard SA (HC engine) recorded 166bhp @ 6000rpm and 156lbft at 4600rpm.

Surely that's not bad considering age/mileage and maybe the autobox, and an SA will have fully loaded engine ancillary options!

As you say, Peter. It's a low mileage car - under 60 thou - which, obviously, is a factor, but I was content with the figures.

[shaunw]

I recently had mine tuned on a rolling road.

1990 SE, 80,000 miles on original engine parts apart from L14 camshafts, K&N filter (direct replacement for original paper filter retaining original airbox etc) and re-jetted carbs.

Result after tuning was 177bhp. Before rejetting the carbs to take advantage of the camshafts the power output across the range was considerably lower, especially below 3000rpm.

I'm sure a Lotusbits manifold and exhaust would get me above 180 bhp. Not bad for a 25 year old engine

Shaun

[MrCoolA]

1989 Hc engine running 253 hp, started out at 180hp ( so the factory said)

[STELL]

Well i've had my car with an LC engine since 2002 and have been satisfied with it. But as i got a hold of a partly smashed car with a HC engine, I've now let a garage fit the HC for me.

I do think the Excel is a great car to drive, and of course an "Old" engine with a carberator is going to be different the an all new fuelinjected all computerized , variable everything engine. but isn't that one of the reasons we love theise cars and engines

I'm not a hot rodder , and to prove that i've fitted the large PNM brake kit up front and adjustable Spax dampers all around, And i have changed the air filter to a G&N

If the engine fails in the future i might concider doing doing it a little hotter with porting the head and a new header sytem and so on

My concern is only of mere intrest
Thank you for your replies

[richardw]

No non-turbo'ed 16v Lotus engine has never felt as fast to me as contemporaries with supposedly similar outputs (2.8i Fords etc). I just put this down to marketing horsepower as stated previously

Well I'd say a kind of marketing horse power. Just looking at peak bhp doesnt tell the full story - it needs to be at a point where you can use it, and the shape of the power curve itself will determine how the engine feels most of the time. As Lotus engines tend to have quite high points at which max torque and max bhp are developed, this is why they feel different (certainly to journos) to engines with more capacity. Unless you are planning to race the car, going for more bhp at higher rpm won't make much difference, and you may lose torque in the process (as experienced by alanbell.) With a 421 exhaust and Lotusbits fuel injection, my 2.2 SE spec engine develops 152ft/lb at 5300rpm, so well down on tonypoll's 162.1@4900, but with a higher power output at high rpm.

Lotus possibly could have softened the max power output and got better mid range torque - but that wouldn't have looked good on paper. For the engine and without a turbo, what they achieved was pretty optimal.

ATB Richard

[amarshall]

Since I've just picked mine up from a couple of hours of screaming torture, here are some figures post-fettling. We didn't run it all the way up to 6500 rpm since the goal was to sort out a problem below 3k, but...

157.3 bhp @5168 and still climbing nicely. Projecting the line onwards would be comfortably close to 180 bhp once above 6k (looks like it's climbing at roughly 15 bhp per 500 rpm at that end of the range).
163.6 lbft@4870

(and that's 24 more ponies and 8 more lbft than it had when it went in - no wonder it's been unhappy).

(HC engine on 95 RON. 206k miles with a refresh (mainly pistons, liners, rings) at 121k.

[Lotus-e-Clan]

Very encouraging!

Was that at Northallerton Angus, or Bogg Brothers @ Malton?

What did they fettle?