How many HP is enough?

[antonio.cocchi]

Murph7355 said:

BertBert said:

...
The concept that tracks are boring unless you up the hp is a strange concept to me. straights are inherently dull so having 260 bhp or more doesn't make them more interesting....

The one time you want more is when on a track day with heavy metal that is hopeless around corners but demonic down straights.

I remember being in my 140bhp 7 on track with a Cerbera and experiencing precisely this. It was getting in the way on the twisty parts, then leaving me for dead on the straights and the process would repeat.

Of course I could hold right back to gain space...but before very long at all I'd be on its tail and the same thing would repeat.

200bhp, plus more practice, saw an end to that.

This is in a K-series car before the Duratec era. Mine was a home brew 200bhp car (DVA head etc) and much more civilised than Caterham's own versions. Eminently usable on the road.

Go much higher in a K-series and usability diminishes quickly IME. Duratecs may be different (never driven one) but a K is nice and light and they sound great on throttle bodies.

I'm in love with a Supersport K 140hp, 5 Speed. What the limit of those engine, without lost reliability, because for sure, at the beginning will be enough but I know myself, I will di something on it After a couple of year!

[Eugene7]

Eugene is 210bhp (well, was when last on the rollers...).

I've had the car for some 35+years, and it started life as a 110bhp xflow.

It's now a rather modified Zetec, still with the Ital live axle, but with LSD and stronger drive shafts/bearings, as well as BGH 5 speed box.

It is also Brooklands Aero, and has been for years.

It is used all years round, and has done many 100k miles, in all weathers, from simple runs to the shops, as well as long tours around Europe (Google YouTube for Le BOG Club...).

Anyway, a long way round to say 200(ish) really is the sweet spot for me.

😎

[antonio.cocchi]

Eugene7 said:

Eugene is 210bhp (well, was when last on the rollers...).

I've had the car for some 35+years, and it started life as a 110bhp xflow.

It's now a rather modified Zetec, still with the Ital live axle, but with LSD and stronger drive shafts/bearings, as well as BGH 5 speed box.

It is also Brooklands Aero, and has been for years.

It is used all years round, and has done many 100k miles, in all weathers, from simple runs to the shops, as well as long tours around Europe (Google YouTube for Le BOG Club...).

Anyway, a long way round to say 200(ish) really is the sweet spot for me.

??

Thanks for contribution!

[keo]

I had a short test drive in a 270 today. First time I have driven a Caterham and it wasn’t a long drive. It drove very nice but I did think it was a little slow. I had a passenger in. I looked at a 420 when I got back to the showroom.

[antonio.cocchi]

keo said:

I had a short test drive in a 270 today. First time I have driven a Caterham and it wasn’t a long drive. It drove very nice but I did think it was a little slow. I had a passenger in. I looked at a 420 when I got back to the showroom.

Slow??? Really?
What's your actual drive?

[Drooles]

I’ve got a 1700 Supersprint with a supposed 135bhp. Fast enough to scare me!

To be fair, with a passenger and a load of luggage you can feel a difference but it’s still quick enough for me. Maybe it feels faster than it is with the noise from the Webers!

[jimPH]

antonio.cocchi said:

jimPH said:

antonio.cocchi said:

jimPH said:

I had 220, but it was lacking, so upped it to 270 and that was much bigger improvement. The only problem was i added a 6 speed sequential, fully stripped and bare bones carbon trimming so it was, how can i put it, a bit harsh. As such, driving was fun, but any more than an hour or so and it was tiring. Always felt a bit too highly strung too and mad me sweat on account of breaking lots of engines, so i sold it.

Was a great car, but if i got another one, it would be geared more towards road use so i can enjoy it more.

Which engine?

2.0 Duratec, 54mm raceline bodies, big valve hi port head, dry sump, saenz rods, hi comp pistons, kent cams plus various other bits. I was going to put extensions on the trumpets and it could have done with a good 4-2-1 exhaust instead of the 4-1, but it was pretty fruity.

Wow...
Reliability?

It was relativelyreliable in my ownership, but I've had bad experiences which raised my doubts. Would overcool in colder weather, as I had a ducted nose, so I opted for a modien oil cooler and ditched the oil to air. Also had the electric water pump as they cavitate at high revs and I was pulling 9k at full chat.

But it was all a bit highly strung and my confidence waned, I guess I went a bit too far in the pursuit of power and I lost driveability and that relaxing sense of enjoying the moment on a warm day with the wind in your hair. Plus the straight box made more noise than the induction roar. It was a beast of a car but sadly built for a purpose which I didn't make full use off.

Eyeing up an exige at some point, providing I stay in a job post covid, but I thoroughly enjoyed the experience of ownership and have some great memories!

My only reliability issue was when I lost oil pressure, turned out then oil pressure sensor wire came loose, bit that was around the time my confidence started to creep in and want long before I sold it. Oh and I missed a shift a needed a gearbox rebuild! Engine had no issues though

Straight cut sequential boxes are a pig on the road! And easy to break if you're a bit ham fisted. I think the car was better than my own abilities!

It was fast though, maybe not the fastest car I've had but it felt like it!

[antonio.cocchi]

jimPH said:

antonio.cocchi said:

jimPH said:

antonio.cocchi said:

jimPH said:

I had 220, but it was lacking, so upped it to 270 and that was much bigger improvement. The only problem was i added a 6 speed sequential, fully stripped and bare bones carbon trimming so it was, how can i put it, a bit harsh. As such, driving was fun, but any more than an hour or so and it was tiring. Always felt a bit too highly strung too and mad me sweat on account of breaking lots of engines, so i sold it.

Was a great car, but if i got another one, it would be geared more towards road use so i can enjoy it more.

Which engine?

2.0 Duratec, 54mm raceline bodies, big valve hi port head, dry sump, saenz rods, hi comp pistons, kent cams plus various other bits. I was going to put extensions on the trumpets and it could have done with a good 4-2-1 exhaust instead of the 4-1, but it was pretty fruity.

Wow...
Reliability?

It was relativelyreliable in my ownership, but I've had bad experiences which raised my doubts. Would overcool in colder weather, as I had a ducted nose, so I opted for a modien oil cooler and ditched the oil to air. Also had the electric water pump as they cavitate at high revs and I was pulling 9k at full chat.

But it was all a bit highly strung and my confidence waned, I guess I went a bit too far in the pursuit of power and I lost driveability and that relaxing sense of enjoying the moment on a warm day with the wind in your hair. Plus the straight box made more noise than the induction roar. It was a beast of a car but sadly built for a purpose which I didn't make full use off.

Eyeing up an exige at some point, providing I stay in a job post covid, but I thoroughly enjoyed the experience of ownership and have some great memories!

My only reliability issue was when I lost oil pressure, turned out then oil pressure sensor wire came loose, bit that was around the time my confidence started to creep in and want long before I sold it. Oh and I missed a shift a needed a gearbox rebuild! Engine had no issues though

Straight cut sequential boxes are a pig on the road! And easy to break if you're a bit ham fisted. I think the car was better than my own abilities!

It was fast though, maybe not the fastest car I've had but it felt like it!

[braddo]

keo said:

I had a short test drive in a 270 today. First time I have driven a Caterham and it wasn’t a long drive. It drove very nice but I did think it was a little slow. I had a passenger in. I looked at a 420 when I got back to the showroom.

Having a passenger certainly makes a big difference. Did the car have much mileage? I hired a 270 from Caterham and it only had 1500 miles on it, so I did wonder if it was still a bit tight and down on power.

For a '270hp/ton' 270 Caterham:

Approx power to weight with just a driver - say 620kg and 135hp = 217hp/ton
With say a 70kg passenger - 690kg = 195hp/ton

So at middling revs or at 60mph+ the acceleration will be brisk rather than quick.

[BertBert]

Murph7355 said:

BertBert said:

...
The concept that tracks are boring unless you up the hp is a strange concept to me. straights are inherently dull so having 260 bhp or more doesn't make them more interesting....

The one time you want more is when on a track day with heavy metal that is hopeless around corners but demonic down straights.

I remember being in my 140bhp 7 on track with a Cerbera and experiencing precisely this. It was getting in the way on the twisty parts, then leaving me for dead on the straights and the process would repeat.

Of course I could hold right back to gain space...but before very long at all I'd be on its tail and the same thing would repeat.

200bhp, plus more practice, saw an end to that.

This is in a K-series car before the Duratec era. Mine was a home brew 200bhp car (DVA head etc) and much more civilised than Caterham's own versions. Eminently usable on the road.

Go much higher in a K-series and usability diminishes quickly IME. Duratecs may be different (never driven one) but a K is nice and light and they sound great on throttle bodies.

I guess for me it doesn't matter, if it turns into an actual pain getting in the way of the enjoyment, just go through the pitlane and start again. I'm only interested in how enjoyable my car is on a track day not really not how it relates to others.
Bert

[mike150]

I have owned.....................

135bhp 6 speed, all gears and no power
170bhp 5 speed, gears where too wide to use the power and there wasn't enough
210bhp 6 speed, good power, sometimes wanted more but didn't really need it plus very involving to drive
210bhp 5 speed, power was ok but felt slower due to the gears
310bhp 5 speed, lots of power but didn't feel as fast as it was due to 5 speed plus you couldn't use it that often on the road

For me my 210bhp 6speed car was the best driving experience. As BertBert said the extra power adds weight and detracts from the whole point of the 7 car.

The best Imo is 200-260bhp 6 speed

But, I shouldn't be here as I don't have a 7 now, I have a Lotus Elise though coincidentally with 220bhp 6 speed

Edited by mike150 on Friday 18th September 13:08

[keo]

braddo said:

Having a passenger certainly makes a big difference. Did the car have much mileage? I hired a 270 from Caterham and it only had 1500 miles on it, .

The car clicked over to 300 miles on my test drive so I did think it would probably be “tight” as well.

Surprising I had a 111R before so roughly 200 bhp per ton and I was happy with that.

[Murph7355]

BertBert said:

I guess for me it doesn't matter, if it turns into an actual pain getting in the way of the enjoyment, just go through the pitlane and start again. I'm only interested in how enjoyable my car is on a track day not really not how it relates to others.
Bert

That's at the root of my comment too - having to go through the pitlane or back off too often just gets dull.

A more powerful car set up nicely still has the delicacy of feel, can be driven in the same way...and then if something looks to getting in your way on the straights you simply go past it.

[Murph7355]

antonio.cocchi said:

I'm in love with a Supersport K 140hp, 5 Speed. What the limit of those engine, without lost reliability, because for sure, at the beginning will be enough but I know myself, I will di something on it After a couple of year!

Biggest piece of advice I'd give is to get a 6spd K car, not a 5spd. The std 5spd ratios are rubbish for a K. The 6spd was designed for it. Ratios can be changed in the 5spd, but that's not all that's "wrong" with it.

The limit for a K is probably 260-270bhp BUT you will need to do a lot of work to get to the top end and it will need a lot of looking after.

A well spec'd 200bhp engine will be tough without too much aggro. Conventional wisdom used to be to keep the revs a good chunk under 8k...but it is fun revving up to there and they sound brilliant.

160-180bhp is straightforward and reliable.

If you're interested in K-series cars, and you should be , then spend some time reading here : http://www.dvapower.co.uk/

No links to DVA other than a very happy customer back in the early days

[skircoatshed]

I’m not a driving god, so 135 bhp through a 6 speed is plenty entertaining for me......although I’m tempted to get the 310 upgrade.

[upsidedownmark]

Hmm.. mine is a 150bhp K with a 5 speed (modified 1.6).

Personally I wouldn't want a 6 speed - well, I might, but I'd also want to change the final drive. The 5 has some niggles, namely 1st is quite short, and when I had 130, it was a bit of a 'change to 5th and stop'. However, 4th in the 5 is the same as 6th in the 6. That'd drive me nuts. If you do tour at all, then trundling along at 70 in 4th would be excruciating. On trackdays, I'd spend quite a bit of time on the rev limiter in top. So on balance, quite happy with the 5 speed (it just occurs to me that actually the 5/6 speed argument is more about ratios/final drive than how many gears really..)

I also think you need to pay attention to more than just BHP.. my K may do 150+, but it does need revs to make that. It's comparatively weak in midrange pull compared to a duratec. Suits me to a T on track, you work for your fun, but I suspect a bigger engine would feel more willing in the more normal rev range.

Lastly, I'm not convinced on the merits of the Murph argument:

Murph7355 said:

A more powerful car set up nicely still has the delicacy of feel, can be driven in the same way...and then if something looks to getting in your way on the straights you simply go past it.

Not to p*ss on anyones chips, just my POV etc, but:
1) Based on comparing my 150ish K to my mates 620S, not entirely true.. his is much more of a blunt instrument and has a totally different character. Yes he's spent a lot on setup etc., but it's just a chunk heavier, particularly in the engine bay, and the engine is a sledgehammer. Yes, it's a pretty extreme comparison. His is mighty fast, and he certainly gets stuck behind a faster class of car, but he still gets stuck.

2) In my view, the fun on track is driving as fast as you can in what you have - with a more powerful car you'll catch far more people, and need to make more passes, so, to some extent, the faster car is worse What it does mean is that the people you get stuck behind will be faster. You'll still find someone that has an ostensibly faster car that outruns you on the straights, but is slow in the corners. It'll just be a faster car. That's just the nature of a caterham, they do massive corner speed - and the nature of trackdays where not everyone is confident to give it everything in the bends, but it's easy to push the pedal down on the straights. When I had an MX5, it was always a BMW. Now it's porsches.. good to avoid the middle of the bell curve, but eventually you have to accept it's a track day, and get over it.

I'm still pondering whether to upgrade mine further.. but I'm honestly not sure it would improve it. To some extent though, I suspect it depends on how you drive.

Edited by upsidedownmark on Monday 21st September 10:33

[Murph7355]

The 6spd box is well matched to the power delivery nature of the K. It's not the number of ratios for sure.

Shift quality is also better IMO.

I toured extensively in mine, including a couple of Le Septs. At 70+ revs are only part of the mix

A powerful K is no heavier materially than a less powerful one.

(For the road I agree btw. And would even suggest 200bhp is enough for trackwork).

Not been on track for a while so may e modern alternatives would be irritating now with "only" 200bhp. But passing other cars was fun.

I don't miss the days my car had 130bhp. Going full cage and no screen is more questionable long term perhaps... We'll see how long I can still get in and out of it

[CharlesElliott]

There are a lot of 150bhp Caterhams about and that's what I would recommend for a good balance.

I race a 150bhp Caterham and it is plenty quick enough.

[antonio.cocchi]

Thanks all for contribution.

[coppice]

I did nearly 50,000 miles in a six speed R400 Duratec . At first I thought the short gearing was absurd , but that is only because road cars have become so ludicrously over geared. I got used to it very quickly , even on 500 mile days , and wouldn't have swapped for a 5 speed.

Fun fact - a six speed Seven's gearing is only a fraction shorter than a Ferrari Dino's .