how much hp is to much in a westfield
Discussion
I think the core issue here is Torque (as opposed to Talk) and how it is delivered. A turbo car with a small(ish) power band and maximum torque at 4K will make a difficult road car. A large displacement V8 will have the same issues where the torque spike over powers the chassis and tyres.
A Rotrex supercharger which makes maximum boost at the redline is a different kettle of fish and is much more like the ultimate NA engine which pulls from low down and has the power at the top as well. But we shall see in a few weeks....
A Rotrex supercharger which makes maximum boost at the redline is a different kettle of fish and is much more like the ultimate NA engine which pulls from low down and has the power at the top as well. But we shall see in a few weeks....
XTR2Turbo said:
On paper may look extreme but on the road the power delivery is so smooth, torque relatively low that it is honestly perfect. No trouble finding traction on normal road tyres at all. A great power band from 2000 all the way to 7500.
Do you have a power/torque graph for that engine? i'd be interested to see it if you have. 
jeffw said:
I think the core issue here is Torque (as opposed to Talk) and how it is delivered. A turbo car with a small(ish) power band and maximum torque at 4K will make a difficult road car. A large displacement V8 will have the same issues where the torque spike over powers the chassis and tyres.
This is very true, but only (as I've said before) because it makes it easier to ensure that you don't actually use all the power that you have at your disposal.There is a simple, mathematical relationship between torque and horsepower; they're effectively different sides of the same coin. Torque is just power, with the time taken away, if you like.
So when we're saying that torque delivery causes the problem, what we really/also mean is that the rapid change in power delivery causes the problem (because it's difficult to modulate). The TVR (and Range Rover, if my P38 is anything to go by) answer to this, incidentally, was simply to give a reeeeaaaallly loooooonnnng travel to the throttle pedal, so that it's easier to meter out exactly the amount of torque/power you want.
But, certainly, a 500bhp 'Seven' is easy enough to drive, provided you can make sure it never actually produces more than 200bhp.
Edited by Sam_68 on Wednesday 18th January 19:38
Sam
You are obviously a well educated guy. Please don't assume I am not the same. I am perfectly aware of the relationship between torque and power.
Very few high powered road cars (or bikes) can use their full potential on the road in less than ideal circumstances but it doesn't stop us owning them and using the throttle pedal/twist grip as required. There are occasions, however, when lots of power can be put down on the tarmac and these are the moments performance cars are built for, not icy back roads in January.
You are obviously a well educated guy. Please don't assume I am not the same. I am perfectly aware of the relationship between torque and power.
Very few high powered road cars (or bikes) can use their full potential on the road in less than ideal circumstances but it doesn't stop us owning them and using the throttle pedal/twist grip as required. There are occasions, however, when lots of power can be put down on the tarmac and these are the moments performance cars are built for, not icy back roads in January.
jeffw said:
You are obviously a well educated guy. Please don't assume I am not the same.
I wasn't. I was agreeing with you: I'm merely pointing out (again - I responded to the same point from Rhinochopig back on page 1) that the reason that less 'torquey' high-powered Sevens are better behaved is that it's easier to ensure that you don't use their power. Not everyone on here may have such an understanding of torque and its relationship to power, revs and gearing.I genuinely do agree with you though - my Griffith was far scarier than my FW is, despite having much lower power:weight ratio, because if it started to break away the torque of the engine would cause the revs to 'flare' before you could react to it (TVR didn't really master the complexities of the long-travel throttle pedal until the Speed 6 generation cars.
). The FW has never once scared me, because it's all nicely predictable, but I don't think I can say that I've ever been in a position where I was able to use all it's available power on the road except the odd occasion when I've Vmaxed it in a straight line and have found myself at full throttle, at peak power revs, in top gear.
jeffw said:
Very few high powered road cars (or bikes) can use their full potential on the road in less than ideal circumstances but it doesn't stop us owning them and using the throttle pedal/twist grip as required.
Again, I agree. There's no law against it.
I'm merely arguing that in purely technical terms, it actually tends to make the car slower - you're carrying more weight, more unsprung weight, and making it more difficult to drive (so you have to allow a greater margin for error).
If you want to spend more money to drive more slowly, most of the time, in trade off for bragging rights, the personal satisfaction of having built a more powerful engine, because you like scaring yourself or, yes, those fleeting moments in perfect conditions when you can exploit every last ounce of the engine's performance, then there's nothing to prevent you.
But there are only two ways of answering the OP's question:
1) On the basis of the current technical limitations of the basic 'Seven' concept.
2) By saying that there is no limit to the horsepower, but that you have to use your own skill and judgement to limit its exploitation.
I'm not building it to go fast(er) on the public road...there are way faster people than me on backroads, I presume they lack imagination or experience. I'm building mine to use on the road (I did 5K road miles in last year, including 2 rallies in France and 2 trips to Spa) but rather to go faster in a Sprint where, hopefully, I can exploit the increase in power. Round Goodwood the car was maxing out at 137 before Fordwater and the same into Les Combes so I'm trying to see if I can get down below 90 secs from a standing start at Goodwood (current best is 94secs) and over 150 at Les Combes.
Edited by jeffw on Wednesday 18th January 19:44
jeffw said:
...there are way faster people than me on backroads, I presume they lack imagination or experience.
Or perhaps they just lack sufficient power to corrupt their chassis? 
There are plenty of cars I can drive faster on backroads than a high-powered Seven, simply because they offer more consistent and predictable levels of grip... though admittedly the limitation most of the time is not power, grip or imagination, it's forward visibility.
Sam_68 said:
Yes, I worded my response badly; I meant to say that it was being used on a track, which offers a more favourable environment (surface) than the road.
As to tyres, I'm sure they were road legal (as were the tyres on the Caterham), but what make and spec were they exactly? The A048's on my Westfield are road legal, but to get enough heat into them to make them start working properly takes some fairly brisk driving on the road, so 80% of the time they're offering fairly limited grip and in the cold or wet they are bloody lethal.
Out of interest, how many road miles has your car done now?
The tyres we used were E marked Kumho ECSTA V700 we also used the same tyres in the wet at Dunsfold (Top Gear Track) achieving a time of 1.30. The car I drove was a friend of mine's who uses the car mainly on the road doing around 1500 miles a year. My car is also road legal but is used mainly on the track. Here is a link of it on slick's on a cold damp day at Bedford http://www.youtube.com/watch?v=qfhymdBb_WY&fea... as for how much hp is to much, surely the fun part of these cars is to have what you want. 100hp will be to much for some people, I have had a 130hp cvh rwd, 360hp cosworth rwd, 400hp 4x4 cosworth, 360hp hayabusa turbo rwd, 400+hp hayabusa turbo rwd, 7 type car'sAs to tyres, I'm sure they were road legal (as were the tyres on the Caterham), but what make and spec were they exactly? The A048's on my Westfield are road legal, but to get enough heat into them to make them start working properly takes some fairly brisk driving on the road, so 80% of the time they're offering fairly limited grip and in the cold or wet they are bloody lethal.
Out of interest, how many road miles has your car done now?
and had great fun in all of them, my advice is to have a go in as many as pos and make your own mind up!!
Edited by busa turbo on Wednesday 18th January 21:30
Edited by busa turbo on Wednesday 18th January 23:36
busa turbo said:
The tyres we used were E marked Kumho ECSTA V700 we also used the same tyres in the wet at Dunsfold (Top Gear Track) achieving a time of 1.30. The car I drove was a friend of mine's who uses the car mainly on the road doing around 1500 miles a year.
Thanks. That's about what I'd have expected, obviously - you don't do those sort of lap times on a set of budget Korean remoulds - but to put it in perspective we're talking about a 'road' tyre whose optimum working temperature is between 70 and 90 degrees centigrade. In other words, if you're not able to burn your hand on them, you haven't been working them hard enough. 
I sincerely doubt that there's anyone here who could get anywhere close to that amount of heat into them with someting as light as a 'Seven' in road use on a regular basis, and live to tell the tale.It's also informative to note that the wet lap time has dropped to around what you'd expect of a top-echelon current generation FWD hot-hatch in the wet.
And we're still talking about the track, of course... throw in a few potholes, white lines, manhole covers and pile of horses
t and it's a different story, wet or dry.The mileage seems about typical for this type of car, too - that's about the same (probably a bit more, actually) as I manage in the FW, which tells its own story - they're not the sort of thing you feel inclined to jump into at the slightest opportunity... it tends to be for relatively short, sharp blasts in perfect conditions, and you come back feeling pretty wired. Great, of course, if that's what you want from them, but it makes them an expensive toy and is probably one of the reasons you see 'hyper'-Sevens changing hands so frequently at minimal mileage intervals.
XTR2Turbo said:
.... the most sensible comment on the thread
If it's possible, of course. Unfortunately, how many of us get the opportunity to drive a range of kit cars with different power:weight ratios and torque/power characteristics to the limit of their deliverable performance, before making a decision on which suits us best?
I've been fortunate to have dabbled with the kit car magazines and made a living (well, a subsistence, maybe...) out of doing chassis set-up on cars in the past, so I've had the opportunity to drive a fair few over the years, but suffice it to say that I thought the Westfield SEight was the most amazing idea ever when it was first launched, and I'd have gone out and bought one there and then had I been in a position to do so... then I drove one.
I've raced a westfield for four seasons now, three of them normally aspirated and last year turbo'd.
When the car was normally aspirated I had a Bob Farnham tuned Hayabusa with MBE Ecu and had a respectable 204hp and 100 ft/lb or 165hp and 84 lb/ft at the tyres.The car weighed 498kg. Thats roughly 400bhp/tonne. I was running on Avon ACB10's and managed, as a benchmark, to do a 52.3s lap at Brands during a race meeting. I won my overall club championship that year and wanted to 'Up my game' a bit.
I'm now running a highly uprated and modified Hayabusa with a TD05 16G turbo with just 10psi giving me 246bhp and 160 Lb/ft at the tyres. I'd guess that's about 290 at the flywheel. The car now weighs 530kg. So I'm slightly under 600 bhp/tonne.
The turbo spools up very smoothly from very low down, it's actually producing double the torque by about 5500 revs making it very drivable, it's nowhere near as frenetic as when it was normally aspirated, but it still revs to 10800rpm.
Last year was really a development year and I've just sorted out a 3.1 diff to extend the gearing.
As the season progresses if all goes well reliability wise, I wil be upping the boost to 14psi, which should give me about 350bhp or 290 at the tyres.
Getting back to the 52 second lap at Brands.... I'll let you know if the extra power is an advantage or not.
I'm aiming at a 49s on slicks, time will tell.
Cheers.
Steve.
When the car was normally aspirated I had a Bob Farnham tuned Hayabusa with MBE Ecu and had a respectable 204hp and 100 ft/lb or 165hp and 84 lb/ft at the tyres.The car weighed 498kg. Thats roughly 400bhp/tonne. I was running on Avon ACB10's and managed, as a benchmark, to do a 52.3s lap at Brands during a race meeting. I won my overall club championship that year and wanted to 'Up my game' a bit.
I'm now running a highly uprated and modified Hayabusa with a TD05 16G turbo with just 10psi giving me 246bhp and 160 Lb/ft at the tyres. I'd guess that's about 290 at the flywheel. The car now weighs 530kg. So I'm slightly under 600 bhp/tonne.
The turbo spools up very smoothly from very low down, it's actually producing double the torque by about 5500 revs making it very drivable, it's nowhere near as frenetic as when it was normally aspirated, but it still revs to 10800rpm.
Last year was really a development year and I've just sorted out a 3.1 diff to extend the gearing.
As the season progresses if all goes well reliability wise, I wil be upping the boost to 14psi, which should give me about 350bhp or 290 at the tyres.
Getting back to the 52 second lap at Brands.... I'll let you know if the extra power is an advantage or not.
I'm aiming at a 49s on slicks, time will tell.
Cheers.
Steve.
StainlessSteve32 said:
Getting back to the 52 second lap at Brands.... I'll let you know if the extra power is an advantage or not.
I'm aiming at a 49s on slicks, time will tell.
An RGB Fury running a stock 1000cc engine on A048s did 50s last year... so maybe you are answering the OP, but perhaps not how you intended!I'm aiming at a 49s on slicks, time will tell.
I've always felt there are a couple of seconds allowed for mental attitude and ability, so maybe the other driver is particularly quick. I'm a consistant driver if nothing else and I'll always give honest times, backed up by officially logged times if anyone wants to see them ;-) there aren't many sevens that put in sub 50s laps at Brands due to the total lack of aero. That's what makes them such good value fun though.
DH2 said:
An RGB Fury running a stock 1000cc engine on A048s did 50s last year... so maybe you are answering the OP, but perhaps not how you intended!
What would be the power to weight of such a car, and how much difference would the extra weight of a supercharged car engined car make to things like braking and corner speed?(im guessing for big power the OP would be looking at car engines)Would you need alot more power to make up for the earlier braking for the bends?
In answer to the OP's question im more than happy with 219bhp (2.0 Zetec on carbs). Its more than quick enough. But it is a personal thing.
I think it would take a lot of power to give you back that first ever drive feeling, where you get a slight tunnel vision and a real sense speed when you plant it. I went from 140bhp to 219bhp and I didn't that feeling back.
I notice that the Sports Special class with the 750 Motor Club, which is for Sevens, even R400's (400 bhp/tonne) has a Brands lap record of 52.9, I'm assuming the RGB is also with the 750 Motor Club.
Just goes to show you can't compare the two.
A Radicals or a Jades have'nt got massive power to weight ratios, but they will do blistering laps... The joys of Aero.
I tried a Radical and preferred the Westfield, the Radical went round like it was on rails, my Westy 'dances', with the steering wheel never really pointing where you are going.
Just goes to show you can't compare the two.
A Radicals or a Jades have'nt got massive power to weight ratios, but they will do blistering laps... The joys of Aero.
I tried a Radical and preferred the Westfield, the Radical went round like it was on rails, my Westy 'dances', with the steering wheel never really pointing where you are going.
DH2 said:
An RGB Fury running a stock 1000cc engine on A048s did 50s last year... so maybe you are answering the OP, but perhaps not how you intended!
Did first trackday of the year in my Westy on saturday at Snetterton....
Felt a little overpowered.... but conditions were hardly ideal!
least it was easy to see where the track went! and yes... if it wasnt slippy enough. Someone dropped lots of oil!
well done to Snets staff and Easytrack for keeping things running on a very tricky day!
Felt a little overpowered.... but conditions were hardly ideal!
least it was easy to see where the track went! and yes... if it wasnt slippy enough. Someone dropped lots of oil!
well done to Snets staff and Easytrack for keeping things running on a very tricky day!
Edited by Porkie on Monday 13th February 16:54
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