The online racing simulator
LX engines
1
(37 posts, started )
#1 - wark
LX engines
Is it just me, or do the LX cars have sub-typical engines?

Most Caterhams I see have about a 2.0l I4 with anywhere between 210 and 250 horsepower.

We've got two cars of this style and, well... IMO the class is still underrepresented.

In S1, the 6 was almost too much to handle, but now it just feels too flat-out everywhere.

I'm interested in what the JeffRs of this community have to say, as maybe I'm just cuckoo.
I want my NG TF in the class . It'd loose on speed but at least the back doesn't step out at every opportunity! Sadly, I only owned one for an hour, I test drove it, agreed to buy it, went away and told my brother and he came down with me to pick it up then begged me to let him buy it, and I gave in...
#4 - wark
They have enough power (well, maybe the 6 could have a touch more so it really felt like a step up from the 4), they just rev too high.

Can't wait for the LX8.
Quote from wark :Well, okay. Half of those engines are still bigger, and I think LFS tracks and physics can definitely handle them.

This cars are heavy, but impressive . The performance win is not that big. The LXs are, like Caterhams, very lightweight. I like the good balance between weight and power.

Sure the LX8 would be fun. Somebody knows how much weight the LX8 had in S1? I'm a post S1 LFS owner.
In 1957 the S1 Lotus Seven F had 1172 ccm with 40 HP.
There was no LX8 in S1. The LX8 was planned for S2, but dropped in favor of the UFR. I believe the reason was that it was even more of a handful than the LX6 in S1.

As a matter of fact, with how the current physics feel in relation to the old S2 physics, I would not be surprised to see the LX8 included in an upcoming incompatible patch. Maybe not the next one, but perhaps the one after. After all, the car was pretty much done at the time S2 was released, or at least so it seemed.
#9 - wark
Quote :
Quote :Caterham power

Starting at 105 bhp up to 260.

The only Caterham with 105hp, is the original design Lotus 7 replica, both its engine and frame are weaker than the other Caterhams. So the lowest Caterham (not Lotus 7) power is 120hp, and more of the 140hp versions are sold, so the popular range is 140hp to 260hp.

The LX6 is weak at 190hp, however, the aerodynamics aren't quite right, allowing a top speed of 160mph, compared to the 200hp Caterham with a top speed of 140mph. Even the 260hp Caterham only has a top speed of 155mph.

There is one option not listed at the web site, the super light with the 260hp, this is considered a custom order. I know a guy who has a super light with a Cosworth (USA) tuned 242hp version of the Ford 2.3 liter Duratec in his super light.
Quote from JeffR :
The LX6 is weak at 190hp, however, the aerodynamics aren't quite right, allowing a top speed of 160mph, compared to the 200hp Caterham with a top speed of 140mph. Even the 260hp Caterham only has a top speed of 155mph.

Did you tested this with factory gear settings?
Quote from kallelix :
Quote from jeffr :The LX6 is weak at 190hp, however, the aerodynamics aren't quite right, allowing a top speed of 160mph, compared to the 200hp Caterham with a top speed of 140mph. Even the 260hp Caterham only has a top speed of 155mph.

Did you test this with factory gear settings?

It's in the official specs for the car from Caterham:

http://www.caterham.co.uk/showroom/index.htm
Wow, those cars have engines with normal rev ranges.... Something I wouldn't mind seeing in LFS TBH.

Are those top speeds gear limited or governed? I didn't see anything about drag limiting the top speed. But I didn't look THAT hard....
Quote from Ball Bearing Turbo :Are those top speeds gear limited or governed? I didn't see anything about drag limiting the top speed.

It's due to the drag and gearing. The gearing is set more for peformance than top speed, even with the 6 speed tranny, 6th gear is not an overdrive gear. Maybe the CSR 260 could go 160mph if geared properly, but it might take a very long run, like 2 miles to get there, not pratical for a track oriented car. In the case of the Caterham, it's low weight tranlates into a good power to weight ratio even at 200hp, but it's drag factor isn't that much better than a standard car, so it ends up with a low power to drag ratio.

The 2006 Z06 Corvette has about the same power to weight ratio, with just about double the power and weight of the CSR 260, and is more aerodynamic. The Caterham is quicker to 60mph, mostly because of better launches with a more rearwards weight bias, but the Z06 is quicker to 100mph and beyond or from a 10mph rolling start. Top speed on the Z06 is 198mph, but it takes a long time and a lot of distance to get there. They needed a 3 mile runway to get the car to 190mph and be able to stop (probably took over 2 miles to get to 190mph): z06190.wmv. 4th gear is good for 160mph, and there are few tracks where a Z06 would have a long enough straight to go faster than 160mph, maybe the final straight of Nordschleife, where the Z06 got a 7:43 lap time.
Ok well that makes sense.

2x the weight needs 4x the power to match acceleration so the CSR should be able to out accelerate your Z06 until drag starts to become unreasonable; and assuming it could get the power down well. If I ever get down to CA maybe you could take me for a rip in the Z06? hehe
The LXs in LFS are far too aerodynamic. Hopefully something that will be changed in a future patch (all road cars are equally aerodynamic - obviously flawed).
#18 - wark
Quote from Bob Smith :The LXs in LFS are far too aerodynamic. Hopefully something that will be changed in a future patch (all road cars are equally aerodynamic - obviously flawed).

You'd think that would be easy to fix if the cars were each given permanent wing settings with 0 downforce... finding out how much drag to give each car is another story.
Quote from Ball Bearing Turbo :2x the weight needs 4x the power

2x weight is 2x power. Acceleration = mass / force. So 2x mass (weight) requires 2x force for the same acceleration. Power = force times speed. For example horse power = force (lbs) times speed (mph) divided by 375 (conversion factor). Since power = force times speed, then 2x force translates into 2x power.

The CSR 260 runs the 1/4 mile in just under 12 seconds, at around 110-115mph. The Z06 runs the 1/4 mile in 11.7 seconds at around 125mph. The Z06 has a slight power to weight advantage over the CSR 260, put slicks on the Z06 and it will run the 1/4 mile in 11.3 seconds around 127mph. 3rd gear redlines at 125mph, so 1/4 speed doesn't vary much between runs, because you hold in 3rd or shift to 4th with not much distance left to go.

Lap times on racing tracks between the two cars (both running slicks) will be close, with the Z06 having a slight acceleration and speed advantage, the CSR 260 having a cornering advantage (since it's lighter, it can run softer compound slicks).
2x weight needs 2x power for same acceleration
2x drag needs 4x power for same top speed

(simplistically)
Quote from tristancliffe :2x weight needs 2x power for same acceleration
2x drag needs 4x power for same top speed

(simplistically)

:doh:

Note to self: think first, post second.

Of course you guys are correct... I believe this deserves a "my bad".... :ashamed:
Just to point it out again, the LX8 is flawed in any rigid body physics simulation because IRL it would have so much chassis flex it would be uncompetitive against the LX6 in a sensible semi-race trim for a Rover V8 (280 bhp max), even if the LX8 was given slicks it shouldn't catch it. The thing in LFS though is apart from the weight and possibly CoG there will be no difference over the LX6. It would be interesting to know how well it would fair with a full race Rover V8 IRL (400+ bhp) not that anyone would bother as it's a lot of money to throw on something so fundamentally flawed.
Quote from tristancliffe :2x weight needs 2x power for same acceleration
2x drag needs 4x power for same top speed

2x drag is also 2x power, at least the way you stated it. 2x drag just equals 2x force to overcome at the same top speed, so just 2x power.

2x speed with same drag factor = 4x force times 2x speed = 8x power.
Quote from ajp71 :Just to point it out again, the LX8 is flawed in any rigid body physics simulation because IRL it would have so much chassis flex it would be uncompetitive against the LX6.

The stock CSR 260 makes 260hp and has a very strong frame, so chassis flex isn't an issue with the real thing. It could issue for the SLR (super light version has a weaker frame), but not for the CSR. As mentioned, I know someone that is running a 242 hp 2.3 liter duratec in his SLR without issues, so the SLR could probably handle 260hp as well. My suggestion for the LX series is to get rid of the number of cylinders concept, make them all 4 bangers, and set the 3 different power values to 140hp, 200hp, 260hp, to match the current Caterham line.
The LX8 doesn't need to be a v8, or not even 8 cyl...
1

LX engines
(37 posts, started )
FGED GREDG RDFGDR GSFDG