I thought that Yokohama developed and produced a version of A048s specifically made for the Elise/Exige.
Yes, you might be right about the passenger and even about your own weight, but I was referring to lap times and best possible handling behavious & performance; not for fun pax rides.
Cheers,
George
I thought that Yokohama developed and produced a version of A048s specifically made for the Elise/Exige.
Cheers,
George
There are many different weights for elise/exige varients and yoko do not produce tyres for them. There are many differences in production weight, for example, of the standard bogo elise during its life (mmc/steel aliboot/grpboot etc) and yoko don’t make different tyres for them and its would be a bit silly of them to do so.
best possible handling behavious & performance; not for fun pax rides.
I think thats too vague a question. If you were to trade 0.5mph average mid corner speed for 1-2s a lap quicker car would you take it?
Mark A will correct me if I’m wrong but in my experience you can do a lot to compensate for additional weight. The mid-corner speed may drop with the mass, but the balance (as-in neutral/oversteer/understeer rather than cornerweights) can remain similar. For a trackday car if the balance remains agreeable (as those with them say it does) but you end up with a quicker end of straight speed and laptime then the entertainment factor has gone up (quicker laptimes, better acceleration, bigger braking events, i.e. more fun). For a racing car it comes down purely to laptime and you’ll do what you can with the balance - the fun comes from the competition rather than the drive - so the discussion of handling as it’s own subject has little meaning.
George,
Quick response as only on line a short time and off to Frankfurt for a conference tomorrow (active suspension so should be interesting).
let me quantify the no change to suspension. My Nitrons are old steel bodied ones and as such suffer a bit of corrosion on the bodies so I can’t change the spring seat height without stripping the damper down so I left it (along with the original spring rates 400/475), especially as it only made only a very small change to rear ride height. The geo was reset to my usual settings. The only thing that actually changed was the wishbone bushes as I’d had enough of the crap Nylatrons so went back to rubber bushes (albeit slightly different stiffness’s).
The 1st trackday I did was Silverstone GP and the only issue handling wise was a touch more understeer. However I think this was partly due to the extra power as opposed to any handling imbalance the problem had mostly gone by the end of the day.
As for roll centre heights, this is based on the suspension geometry hardpoints and ride heights, as this is unchanged they will be the same. To actually measure the CofG of the car is not a simple task but the Honda engine CofG has been measured, and I’m not concerned . (I can’t quote figures as it cost someone quite a lot of money to get this done as part of engine mount development so no way it will become public knowledge).
I find it amusing when people describe the next best thing in geometry settings as 99% of people will assume their car handles brilliantly after having it set up, but it was probably so far out previously that std setting would feel brilliant. Small changes in toe can make a difference but 0.1mm is almost impossible to measure so while it will have an effect it will be difficult to feel. The thing is as well that people think Front geo affects the front and rear the rear but as you know this isn’t the case.
People talk about the addition of 40Kg having a massive effect, but as some don’t seem inclined to believe the fact this weight is in front of the rear axle towards the centre of the car, the effect is much less than people anticipate. Having weight hung out the back of the car will affect the balance a lot more, it’s simple calculation based on momentum. Add in the differing driver weight (something I’m not short of I’m sure you will agree) and you end up with some much larger effects.
Then add in the weight difference between various cars, seats, safety equipment, Stereos, trim, the thickness of the clams (as these change) and it’s not difficult to get some big differences. Just look at Uldis’s car weights, that is below the quoted figures (although slightly short on fuel).
So what does your car weigh at this point?
703kg
I will post up complete cornerweights for before and after when its done.
As for roll centre heights, this is based on the suspension geometry hardpoints and ride heights, as this is unchanged they will be the same. To actually measure the CofG of the car is not a simple task but the Honda engine CofG has been measured, and I’m not concerned . (I can’t quote figures as it cost someone quite a lot of money to get this done as part of engine mount development so no way it will become public knowledge).
Ok, it is classified, although it is not so difficult to be measured. Anyway, do you at least agree that more engine weight in the Elise means transfer of the CoG a bit to the rear and higher? Consequently more load transfer and roll angle during cornering? If the tyres are made for the original K-Series Elise/Exige, this means that the total maximum potential lateral force generated is less.
The other issue of the extra weight is the extra inertia, which affects the way/rate the car accelerates, decelerates, and change direction of travel.
Again, I have to admit that the differences may be very small, but I think the whole issue and topic of this extended discussion is the perfection of the Elise/Exige. We are talking for nano-quantities, but according to many others including myself, these tiny details can help you win a race, or offer you a bit of extra pleasure during driving. In my opinion, these small details separate the perfectionists to the rest.
I find it amusing when people describe the next best thing in geometry settings as 99% of people will assume their car handles brilliantly after having it set up, but it was probably so far out previously that std setting would feel brilliant. Small changes in toe can make a difference but 0.1mm is almost impossible to measure so while it will have an effect it will be difficult to feel. The thing is as well that people think Front geo affects the front and rear the rear but as you know this isn’t the case.
By 0.1mm I was referring to the bump steer. According to Lotus, you have to set it up properly. Check the following graph.
[image]> http://i69.photobucket.com/albums/i48/GeorgeLotus/bumpsteer.jpg> [/image]
I think this means that even 0.1mm can make a difference. Otherwise, why would anybody bother? Anyway, that was just an example to show how small changes affect the handling behaviour of the car.
In any case, I am not trying to argue with anybody, I am just trying to present the facts the way I see them. If I could choose between a N/A Honda and a 210 BHP K-Series, I wouldn�t even think about it. Now if I had to choose between a S/C Honda and a 270-280 BHP K-Series, then there are some other questions I should answer first, such as:
1.Which will break earlier; the S/C Honda or TWO such K-Series?
- Money depreciation?
- Maintenance costs,
4.Future potential issues regarding the Honda conversion (electrical problems, driveshafts, etc).- Can I buy parts of the Honda conversion (i.e. engine mounts, wiring looms) and replace any damaged/worn myself? Or do I have to visit the dealer/specialist who did the conversion?
- Do I have to chop down the rear subframe, like one I�ve seen in one specialist (very disappointing view�) or can I get away with the Honda without cutting it at all?
- Will any heat issues affect me or my car?
- If I try the Honda route and not happy, can I reverse the car back to its 100% original state (with the Rover engine), without paying about �2k in parts?
- Do I have the time/money to deal with any issues in respect of handling if chose the Honda?
- Can I pass MOT with the K-Series?
- Which is more driver-friendly engine?
Etc�On the other hand and if money is not an issue (which isn�t the case for me!), then I would definitely chose again the Rover engine.
I am sure many of you believe that Honda or Audi conversions are better than the Rover engine, and I respect this. I would have gone for a DIY Honda conversion myself, as it would have cost me less than building a proper K-Series engine, but decided not to at time being. In the end of the day it�s all about money.
My thinking exactly!
Anyway, do you at least agree that more engine weight in the Elise means transfer of the CoG a bit to the rear and higher? Consequently more load transfer and roll angle during cornering? If the tyres are made for the original K-Series Elise/Exige, this means that the total maximum potential lateral force generated is less.
The other issue of the extra weight is the extra inertia, which affects the way/rate the car accelerates, decelerates, and change direction of travel.Again, I have to admit that the differences may be very small, but I think the whole issue and topic of this extended discussion is the perfection of the Elise/Exige. We are talking for nano-quantities, but according to many others including myself, these tiny details can help you win a race, or offer you a bit of extra pleasure during driving. In my opinion, these small details separate the perfectionists to the rest.
By fitting different springs and dampers to an Exige you make a much bigger difference to the roll angle and rate and to potential lateral acceleration than adding a few kilos towards the centre of the car, so your comments on tyres are not very relevant. Not to mention driver and passenger weight differences, Lotus use the industry standard of 75kg when setting the car up, I weigh a lot more than that, so do many others.
As for the change in roll angle and CofG. as I stated before, no-one denies that the Honda engine is heavier, but the actual change is what keeps getting disputed, I’d be happy to actually measure the CofG for my car (If I had some decent scales) but the actual figures would be fairly irrelevant as I have no-idea what it used to be as in it’s previous state it would be different to other Exiges, but I suppose it would give a rough idea. You only have to look at a few pictures of cars with both engines in them to see what that the engine locations aren’t hugely different, and the Honda engine isn’t mounted a lot higher like people claim. (Picture of my car below on the rollers after it had just had the Honda fitted.) So while there will be some changes and the extra weight does make a small difference, it isn’t that significant and it isn’t that difficult to make up for any change using different geo, spring rates, bushes damping etc. As for comments on perfection, what is that? How do you quantify it? Perfection to one person is totally different to what another believes (which makes road car set-up an absolute nightmare as you can guess). As far as racing is concerned, do you plan to take different springs to a race meeting to change dependant on the weather? What weather and temperature do you set the car up for? There are so many variables that any small changes can affect that perfection is never possible.
[image]http://www.cplracing.co.uk/htmlarea/uploaded/Lotus%20Honda%20014%20400.jpg[/image]
![http://www.cplracing.co.uk/htmlarea/uploaded/Lotus%20Honda%20014%20400.jpg[/image]](http://www.cplracing.co.uk/htmlarea/uploaded/Lotus%20Honda%20014%20400.jpg%5B/image%5D){kind=link}
By 0.1mm I was referring to the bump steer. According to Lotus, you have to set it up properly. Check the following graph.
I think this means that even 0.1mm can make a difference. Otherwise, why would anybody bother? Anyway, that was just an example to show how small changes affect the handling behaviour of the car.
0.1mm of toe change in bumpsteer is a lot different to a change of 0.1mm in static toe. So my misinterpretation.
In any case, I am not trying to argue with anybody, I am just trying to present the facts the way I see them. If I could choose between a N/A Honda and a 210 BHP K-Series, I wouldn�t even think about it. Now if I had to choose between a S/C Honda and a 270-280 BHP K-Series, then there are some other questions I should answer first, such as:
1.Which will break earlier; the S/C Honda or TWO such K-Series?
2. Money depreciation?
3. Maintenance costs,
4.Future potential issues regarding the Honda conversion (electrical problems, driveshafts, etc).
5. Can I buy parts of the Honda conversion (i.e. engine mounts, wiring looms) and replace any damaged/worn myself? Or do I have to visit the dealer/specialist who did the conversion?
6. Do I have to chop down the rear subframe, like one I�ve seen in one specialist (very disappointing view�) or can I get away with the Honda without cutting it at all?
7. Will any heat issues affect me or my car?
8. If I try the Honda route and not happy, can I reverse the car back to its 100% original state (with the Rover engine), without paying about �2k in parts?
9. Do I have the time/money to deal with any issues in respect of handling if chose the Honda?
10. Can I pass MOT with the K-Series?
11. Which is more driver-friendly engine?
Etc�On the other hand and if money is not an issue (which isn�t the case for me!), then I would definitely chose again the Rover engine.
I am sure many of you believe that Honda or Audi conversions are better than the Rover engine, and I respect this. I would have gone for a DIY Honda conversion myself, as it would have cost me less than building a proper K-Series engine, but decided not to at time being. In the end of the day it�s all about money.
Again, I think you miss the situation regarding what you do or don’t get with a Honda set-up. Sure there is a small weight difference, but other than that I don’t see a downside. The engine and gearbox (with ecu etc) costs �2500, a lot less than a similarly powered K-series. You need to mod the Honda ECU for �700, same cost as an Emerald for a K-series. So other than a bit of rewiring nothing changes there.
I doubt anyone fitting a modified and uprated K-series would use the standard engine mounts anyway, so you need to factor in that cost as well.
Then a 210bhp K-series is at least 10bhp down on a std N/A Honda. (Mine was 224bhp or 221bhp depending on which rolling road you believe, these figures were taken 2 days apart). You also get a close ratio 6-speed gearbox, more money needed on a hot K-series for a decent gearbox. This is what doesn’t get mentioned by Simon when he quotes costs for anything. It is possible to do a DIY Honda, it is after all exactly what the Edwards Boys did on their own car originally.
I don’t knock anyone who goes down the K-series route, and personally if they needed help with something I knew about or had access to then I would help them. I think the whole concept of Steve Butts car is great, and I’m looking forward to seeing how SeanB’s car goes next year.
I just get fed up with people who don’t actually know what they are talking about, and this isn’t aimed at you, stating something as a fact which is based on supposition and guesswork.
In about 4 months time we will be going down the Honda route. So, in the interests of providing factual information, if anyone has the right measuring scales etc then ours could be used as a guineapig.
Mark,
I think you do not speak as an engineer, but like somebody who is trying to explain things with pictures, assumptions and guesses. I believe you do this not because you can�t explain things scientificaly, but to help people who are not engineers to understand what you mean. Fair enough.
So in the same level, let me ask you a simple question:
If you had to chose between your Honda engine and another identical engine which is 30 kg lighter, what would you have done?
So in the same level, let me ask you a simple question:
If you had to chose between your Honda engine and another identical engine which is 30 kg lighter, what would you have done?
George, that is such a moronic question. The true question is, what proven ‘identical’ alternative is there?
As we know Simon E is aiming to provide one, but currently it is not widely proven and from the open discussion on this forum it appears that a number/all of the key bits aren’t commercially available to the general public. Therefore, of the options available the Honda is a perfectly reasonable choice. Owners can always change back in the future should they so wish.
Mark,
I think you do not speak as an engineer, but like somebody who is trying to explain things with pictures, assumptions and guesses. I believe you do this not because you can�t explain things scientificaly, but to help people who are not engineers to understand what you mean. Fair enough.So in the same level, let me ask you a simple question:
If you had to chose between your Honda engine and another identical engine which is 30 kg lighter, what would you have done?
George,
I’m struggling to understand where you are coming from?
As I haven’t measured the CofG, or measured lateral or longitudinal accelerations on my Exige with either the K-series or the Honda then the comments I make are based on my experience gained testing cars at work over the last 15 years and subsequently the differences I felt on my car after driving it flat out around various circuits across Europe. So my assumptions as you put it are based on what I have experienced. As for guessing, what are you doing, have you actually driven an Elise or Exige on track at the limit, with a K-series and a Honda?
As I don’t have the figures how can I state them, also what scientific responses are you expecting, that an increase in CofG height increases the roll angle, the fact I am using rubber bushes changes the ride height and hardpoints a very small amount so this will change the roll centre height slightly (compared to a car on Nylatrons) and then there is the relative effects based on both all with a few equations thrown in? Sorry I tend to post on forums for everyone’s benefit not a few people who happen to have the Millikin book on their bookshelf.
What are you expecting me to say on what engine I would use, that if there was a 30kg lighter version of the Honda would I fit that, yes if it wasn’t a huge price increase. Would I fit a K-series engine with 210bhp that is 30kg lighter than my Honda engine, then no I wouldn’t, as it will cost more money in the 1st place to get the same performance (gearbox etc), not to mention in the long run as it will not last as long as the Honda will (based on all the current real data available), and if the worst happens the K-series will cost another �5k while the Honda will be another �2.5k(incl G/Box). I went through the cost calculations when I made the decision and chose the Honda for performance vrs cost. I did take into consideration handling changes in that, based on driving a few converted cars that guys I know own.
I really don’t understand how people can’t just accept the fact that a Honda and an Audi engine are slightly heavier than a K-series, even the actual change is open to question as different cars give different results. The changes to CofG height and moment of interia are unknown, as no-one has ever measured it, they have probably changed very slightly but unless someone has actually measured it (back to back on the same car with the same spec apart from engine change) then it’s impossible to claim conclusively that it has changed.
I found this Walshy�s statement in Seloc:
�the weight of a honda over a k is a pain when braking and cornering.�
http://forums.seloc.org/viewthread.php?tid=107044&page=4
It seems that at last someone agrees with me!
He is also refering to the extra weight the honda has to carry as part of the regulations.
He is also refering to the extra weight the honda has to carry as part of the regulations.
That was what he was actually talking about.
He is also refering to the extra weight the honda has to carry as part of the regulations.
That was what he was actually talking about.
Its strange isn’t it - given how massively heavy the conversion apparently is then you would expect no ballast at all.
Ballast?
I thought it was just that the Honda cars have a higher minimum weight.
The minimum weight for an Exige S1 is 730 Kg, for a Honda Exige S1 is 780 Kg.
Given that I’ve never seen a Honda Exige that weight less than a stock one, It can’t be called ballast.
On the SC Honda Exige, it’s 840 Kg, because they’re considered as 300 BHP.
Easy to understand, methinks.
Simon
Please just keep to the facts, not opinions, there’s a good chap - thanks in advance.
On the SC Honda Exige, it’s 840 Kg, because they’re considered as 300 BHP.
Easy to understand, methinks.
whats Walshy running in the series?