Saw a Lotus Elise up close and personal today

[PC-Engine]

Here is a picture of the engine.

http://www.rsportscars.com/foto/10/exige240r05_engine.jpg

Anyway I don't see any reason why they couldn't just make ducts from the side scoops to the intake manifold. Are you sure the hood scoop is for the intake? Seems like it might be for the intercooler.

AEM also makes CAIs for midengined cars like the MR2 so I don't see a big obstacle there.

 

[Ty]

911 noble?

they have only made:

M12 (GTO-3R)
M400 (the one i read bout being available as a kit car in the US)
M14 (not sure it's entered production yet)

website is here http://www.noblecars.com/home.htm

so not sure what you mean... you have got something muddled up (porsche 911 + noble m12 = noble 911?)

Ah, that was likely it. I caught the show halfway through and it looked so much like a porsche to me that I thought it was a "super" version of one.

 

[Phil]

Here is a picture of the engine.

http://www.rsportscars.com/foto/10/exige240r05_engine.jpg

Anyway I don't see any reason why they couldn't just make ducts from the side scoops to the intake manifold. Are you sure the hood scoop is for the intake? Seems like it might be for the intercooler.

AEM also makes CAIs for midengined cars like the MR2 so I don't see a big obstacle there.

Ah that pic does it as well. Yeah, the top part is the intercooler, but if you do a bit of research, you'll see that the performance of the intercooler and therefore the supercharger is dependend on how much of cooling air the intercooler receives. If the intercooler doesn't get enough cool air to cool the compressed air, the performance of the supercharger goes down. From what I understand is that the top air-intake that is used for the intercooler is far too small.

Here's a photo to show how small the top air-intake really is:
http://www.conceptics.ch/_temp/exige.jpg

If you want, I can go and messure the size of the thing - it's really tiny.

 

[Sage]

oh wow, the pics i'd seen it was much larger

 

[PC-Engine]

Here is a picture of the engine.

http://www.rsportscars.com/foto/10/exige240r05_engine.jpg

Anyway I don't see any reason why they couldn't just make ducts from the side scoops to the intake manifold. Are you sure the hood scoop is for the intake? Seems like it might be for the intercooler.

AEM also makes CAIs for midengined cars like the MR2 so I don't see a big obstacle there.

Ah that pic does it as well. Yeah, the top part is the intercooler, but if you do a bit of research, you'll see that the performance of the intercooler and therefore the supercharger is dependend on how much of cooling air the intercooler receives. If the intercooler doesn't get enough cool air to cool the compressed air, the performance of the supercharger goes down. From what I understand is that the top air-intake that is used for the intercooler is far too small.

Here's a photo to show how small the top air-intake really is:
http://www.conceptics.ch/_temp/exige.jpg

If you want, I can go and messure the size of the thing - it's really tiny.

Yeah that is indeed small, still as I said you have two very efficient side scoops that can be easily ducted over the engine compartment and hency the intercooler. There are other options too like a fan mounted over the intercooler for forced air convection but that also takes away some power. Do you know how the intake manifold gets cool air? Is it just an open airbox that gets air from the engine bay or does it get cool air directly from the side scoop(S)?

On a side note Suburu and Mitsubishi has a neat little water spray over the intercooler in the WRX STi and EVO VII.

 

[Simon F]

On a side note Suburu and Mitsubishi has a neat little water spray over the intercooler in the WRX STi and EVO VII.

That sounds a little like what some Lotus Esprits had. They had (IIRC) a "charge cooler" which was just some volume of water into which they dumped the heat from the turbo. It did eventually heat up to the same temperature as the compressed air, but not before the car had reached some stupid speed.

 

[Phil]

Do you know how the intake manifold gets cool air? Is it just an open airbox that gets air from the engine bay or does it get cool air directly from the side scoop(S)?

I'm honestly not sure, but I wouldn't be surprised if it just gets it from the engine bay which would be under a flow of air from the side scoops anyway.

That's something I could find out though.

 

[rusty]

speaking of cooling the intercoolers, one of my friends has a "halo" on his intercooler which uses compressed CO2 to really cool down the intercooler - similar contraptions also use Nitrous oxide.

really cools down the air and you get quite a big power boost.

 

[DeathKnight]

On the topic of the Elise, I drove past one a few weeks ago (he was going the other way). It's pretty slick. Not surprising I saw it though since the town I live in is right next to an extremely rich village (Indian Hill). I've also seen a couple Ferrari's, Dodge Vipers (GTS), NSX's, a Ford GT, and plenty of Corvettes (although the Vette's generally aren't anywhere near exepensive as the others).

 

[PC-Engine]

On a side note Suburu and Mitsubishi has a neat little water spray over the intercooler in the WRX STi and EVO VII.

That sounds a little like what some Lotus Esprits had. They had (IIRC) a "charge cooler" which was just some volume of water into which they dumped the heat from the turbo. It did eventually heat up to the same temperature as the compressed air, but not before the car had reached some stupid speed.

Wow, I didn't know that. I like your not before the car had reached some stupid speed comment.

I'm honestly not sure, but I wouldn't be surprised if it just gets it from the engine bay which would be under a flow of air from the side scoops anyway.

Even that could be a problem since if it's not ducted all the way to the intake, the cool air will just mix with the hot air from the engine compartment and create warm air. I think something like a CAI directly coupled to the intake then ducted to one of the side scoops would be perfect. This way the other side scoop and hood scoop could be ducted to the intercooler. 8)

 

[Phil]

Even that could be a problem since if it's not ducted all the way to the intake, the cool air will just mix with the hot air from the engine compartment and create warm air. I think something like a CAI directly coupled to the intake then ducted to one of the side scoops would be perfect. This way the other side scoop and hood scoop could be ducted to the intercooler.

True, though I'm sure Lotus Sport thought of that as well. In anycase, I wasn't sure if I recalled correctly, but a friend of mine (Lotus owner as well) confirmed that he heard that the cooling air for the supercharger is fetched through the engine bay as well. So as far as *I* understand it - the supercharger fetches air through the engine bay or at least close enough to the side-scoops for it to be less of an issue, which is then compressed (and ultimately heats up) after going through the intercooler at the top which fetches the cooling air from the top scoop.

The main problem herein with this solution apparently is that the performance of the intercooler is severely limited by the amount of air it fetches through the top scoop. This might not be a big problem under cold/warm weather conditions, but on a hot day on a track when the air is already warm/hot before it even gets to the supercharger and then heats up even more, you're definately going to run into problems which ultimately is a damn shame because the Exige shines most on a fast track and *warm* weather conditions (the Yokohama 048s really start to shine once the surface and tires have a certain temperature - the grip then is absoluetely A-S-T-O-N-I-S-H-I-N-G! ).

BTW; as promised, here are some pictures of the 240R I took at the automobile salon this year in Geneva:

http://www.conceptics.ch/_temp/240r_01r.jpg
http://www.conceptics.ch/_temp/240r_02r.jpg

Not very revealing unfortunately, but at least a more or less nice view into the engine bay..

That sounds a little like what some Lotus Esprits had. They had (IIRC) a "charge cooler" which was just some volume of water into which they dumped the heat from the turbo. It did eventually heat up to the same temperature as the compressed air, but not before the car had reached some stupid speed.

It's really a damn shame that they stopped producing Esprits: it was a damn fine car. Bloddy American restrictions + Renault! Actually, I saw a 2nd hand Esprit V8 (the very first version that launched in 1997) at the dealer last night - a red one. Very nice. And the performance is quite respective too... if only they could have gotten a better gearbox...

 

[PC-Engine]

It's really a damn shame that they stopped producing Esprits: it was a damn fine car.

I'm sure you already know it's coming back in 2007. Oh btw that intercooler looks huge from that angle. Also I wasn't aware the Exige even room for a trunk!

I hope Lotus brings the Exige to the US in the next few years when I can finally afford one. 8)

 

[Phil]

I'm sure you already know it's coming back in 2007. Oh btw that intercooler looks huge from that angle. Also I wasn't aware the Exige even room for a trunk!

Yeah, but if its anything like the concept pictures I've seen floating around the web... meh :? I really liked the classic look of the Esprits. Sleek, elegant.... and the weight was quite low with ~1380kg which I think also spoke for the Lotus developed bi-turbo engine which was surprisingly light for an engine...

The trunk - yeah, it's got enough room for jackets and some hand-luggage which can come quite in handy since the interiour is quite scarce with little room behind the seats.

View: Interiour
View: Seats

I hope Lotus brings the Exige to the US in the next few years when I can finally afford one.

It's not out yet? I'm not sure, but I thought my dealer mentioned that the waiting list is growing in Europe as well because of Exige's finally getting to the US... I assumed you'd have them by now if not by around christmas this year...

In anycase, not sure how easy importing is and how prices compare - but if you're looking for a good 240R alternative, we've got the Exige with 265bhp which is quite affordable...

here are the pictures (the supercharger/intercooler is hidden under the engine):

Exige Bemani Kompressor 1
Exige Bemani Kompressor 2


BTW; were you aware that you can take the roof off?

 

[PC-Engine]

BTW; were you aware that you can take the roof off?

No I wasn't.

That means it'll be perfect for those topless drives that I thought would only be possible with an Elise.

 

[Phil]

Lotus Exige 240R

Following up on my previous rant on Lotus's Exige 240R, it does seem that a few of them made it into the world.

Stats:

Torque: 236Nm @ 7000 rpm
Weight: 941kg
Weight front/back ratio: 36.6% / 63.4%
Power: 247PS or roughly 243bhp / 182kW


Well, the results, while expected, I hate to say it, are quite disappointing:

Results:

0 - 100km/h: 5.2s
0 - 160km/h: 12.7s
0 - 180km/h: 16.8s

topspeed: 249km/h

80 - 120km/h in 4th / 5th / 6th gear: 4.8s / 6.9s / 8.7s

As a reminder, Lotus claimed the 0-100km/h stretch in less than 4 seconds, which is far from the achieved 5.2s. The article doesn't mention any reasons, but as I ranted above, I suspect the problem lies within the insufficient cooling measures Lotus took.

The standard Exige does the 0-100km/h stretch in roughly the same time. It is slower at higher speeds, but not by much (0-160km/h in 14 seconds I think).

As reference, the supercharged Exige overhere with 265PS and 250Nm available at 4000 rpm does the 0-100km/h stretch in 4.3s (and that was in winter with the summer tires - Yokohama's 0048 - at 3°C). It does 0-160 in 9.7s (3 seconds faster) and accelerates to 200km/h quicker than the 240R reaches the 180km/h mark (0-180km/h in 12.1s, 0-200km/h in 16.5s).

The difference? More sophisticated cooling which in turn allowes for slightly more power - power that is there even during hot days on the track.

 

[PC-Engine]

265 > 247 so of course it would be faster...

It has little to do with cooling. Remember, on a dyno hp/ps is rated while standing still not moving....

 

[Phil]

265 > 247 so of course it would be faster...

It has little to do with cooling. Remember, on a dyno hp/ps is rated while standing still not moving....

I wasn't talking about how the hp/ps are rated - I was saying that the reason that the 240R fails in outspeeding a standard Exige with 50bhp less is because the supercharger is under performing because cooling-measures from the hood-scoop is insufficient, especially during low speeds / or overheating through extensive reving like on a track.

If you had one of these, you could forget about taking the roof off as even less air would go through the hood-scoop.

 

[PC-Engine]

I wasn't talking about how the hp/ps are rated - I was saying that the reason that the 240R fails in outspeeding a standard Exige with 50bhp less is because the supercharger is under performing because cooling-measures from the hood-scoop is insufficient, especially during low speeds / or overheating through extensive reving like on a track.

If you had one of these, you could forget about taking the roof off as even less air would go through the hood-scoop.

But you're not understanding the error in your logic. HP/PS is rated by using a dyno. According to the dyno Exige A has 247 hp/ps while Exige B has 265 hp/ps. This has nothing to do with cold air since the Exige being dynoed is stationary ie no forced air cooling. The fact SC B provides more power than SC A is simply due to the fact they're different SCs. This is common knowledge. In fact you can increase hp/ps on the same SC by changing pulleys in the same way you can increase hp/ps on a turbo by increasing boost. It has nothing to do with cooling. So in summary more hp gives you faster acceleration if the weight of the car is the same.

 

[Phil]

You are wrong in your assumption that I am comparing it with the other supercharged version: The comparison is much simpler as in that the standard Exige with 189bhp is practically as quick as the 243bhp version, despite the significant power difference. The weight stats I have posted above indicate that the cars are roughly the same weight (a standard Exige weighs in at a bit over ~900kg while the 240R is ~940kg).

In short, the 240R has an advantage over the standard Exige in power/weight ratio and it has more torque at lower revs. All else being equal, this should make for better times, yet it doesn't.

As you said, the power is measured while on a dyno - yet, 0-100km/h sprints aren't. If the supercharger is underperforming because of insufficient cooling, you'd notice it in acceleration sprints in which the supercharger gets less air (low speeds; higher the speed, the more air goes through the air-intake) or when the engine is generating a lot of heat like for example on a hot track day through extensive usage.

The other supercharged Exige with different cooling and ~7% more power (~20bhp) than the 240R shows that if effectively done right, the supercharger is much better utilized and effectively used which in turn results in much improved times as is expected from a power / torque advantage, all else being equal.



At the end of the day, facts remain and that is: Lotus failed in reaching 4s from 0-100kmh - they even failed in significantly beating the standard Exige despite 50bhp more power, more torque which is available at much lower revs - which should make for the biggest advantage as the standard engine suffers from very low torque at low revs (the fun starts above around 5800 rpms).

 

[PC-Engine]

The data is not enough to conclude that the 0-100km time is due to insufficient cooling. What is the standard Exige's 0-100km time? Was the gear ratios on the SC Exige optimized for the new torque curve or did it use the same as the standard Exige? Did they keep the cam change switchover point the same? The SC Exige is 40kg heavier and the SC also robs power from the engine due to it being a SC vs a turbo. There're just too many factors involved to pinpoint a problem.