Re: GT4 - Redline Specifications

[Tomte]

I just noticed that you use the 968 shadow model. Do you want to have the wings file do modify it a bit? Atm, your redplug is dependant on the 968 and the Gallardo plug.

I noticed that the driver is quite committed to his car, he even has a rollcage going through his body. And he sits on the passenger seat, which isn't there.

[theSnail .@y]

Hehehe, I've asked c14 for a proper shadow model - but thanks anyway.
I borrowed it because I hate cars without shadows. I should have asked before, but sometimes I'm baaad … Sorry.

I'll make changes on the driver (I did not check the result - thanks for spotting this) and the steering wheel (baaad again ) next week-end.

[pEsT]

no more problem here with the Z4. don't know what happend.

[alphonse]

I like the GT4 cars a lot.
Its a different handling than TCC or GT3 (no surprise) so we have a new challenge to get them as fast as possible around the tracks.

Although cars have all their "own" characteristics they are close to the same in overall performance.
The Z4 together with the Nissan are easiest to handle for me at first glance.

The Cadi is a "little fat lady" and i like its handling a lot too.
The Porsche is exactly what i expected it to be (this aint bad - but is it good?).

Hardest for me to control as i loose it much more often than all the others is the Z3. It might be just me - but i am not made for this up to now.

thanks for all the work in advance - hope something good arises out of it!

alf

[Tomte]

Thanks for the feedback. I'm a little bit astonished that the cars appear to be close.
The Z4 will probably be the easiest of the bunch, it's a well sorted chassis to begin with (thanks Andreu!!!). It doesn't understeer too much and is generally well tempered.
The 968 is again a tricky issue, it was born as a test car before I had access to the rest of the pack. I'm not sure if I will include it in the final pack, as this is really getting the last drop of blood out of that ageing car. I can't say if it is any good or just a boring, predictable ride.
The Caddy is exactly that, a little fat lady. I hope she's competitive enough.
Now, the Z3 M Coupe is a different matter. The lightest of them all, only 5 gears, twitchy... and what do you get in return? I can't answer this question for the moment, I haven't found out yet.
As for the 350Z... it's time I get my ass into that car.

[leoantix]

As for the 350Z... it's time I get my ass into that car.

lots of power and lots of fun ... yet the over-steer is a bit extreme in my opinion

keep up the good work ... i smell a new tourney in the near future

[Tomte]

Ok, it hasn't the quality of DJ's epic Redline clips, but I thought I share some of the fun I had today:

[alphonse]

nice one Tomte,

really - really close in last curve though

had some fun with snail and friends on gt4 testing - looks like great fun is coming up!
the nissan is a fast beast - and given your vid the M3 can even be handled...

looking forward for some action...

alf

[Tomte]

latest news... well, not much to report really.
The physics appear to be well sorted already, but further scrutiny is probably needed.

I redid the UV map of the Z3 M Coupe to be able to create some meaningful skins. Looking at my first car model I saw a lot of things I would do differently now,...

The Z4 M Coupe could also profit from a new UV map. The current one is a great combination of lights, windows and body panels, mirrored and so on. All in all very efficient stuff, but not very easy to create some racing skins without running into the Redline Golf mirror issue. Andreu? Would you, ahem, be willed to, well, create a new UV map for the body only? Pretty please? We could keep the current for windows and lights and maybe use a new material for the metal bits.

As for the XLR... we also need new skins here and maybe a little cleanup of the materials.

All in all I don't see that the GT4 class is far enough in the development process to warrant a tourney this year. Well, the 350Z is actually near ready, but I'm not...

[Battlewagon]

Yes, I also find the 350Z pretty boring. That's why I really don't want to work on any GT4 car now. I'd much rather finish the RS200.

While I'm already posting pictures of possible GT4 cars:



A thomm-free Caterham, a VX220 Opel replacement, a Marcos Mantis Gillet replacement, and a Morgan Aero 8 Donkervoort replacement. The rear wings will have to go, of course.

I just read a few days ago that the Morgan 4-4 is now the oldest model of car in continuous production. Is this true?

[Valentin K]

I just read a few days ago that the Morgan 4-4 is now the oldest model of car in continuous production. Is this true?

Could be. It was launched in the 1930's, that's why it still uses a wood frame and a 100 year old front axle construction. But the Aero 8 is completely different from it.

[Battlewagon]

I just read a few days ago that the Morgan 4-4 is now the oldest model of car in continuous production. Is this true?

Could be. It was launched in the 1930's, that's why it still uses a wood frame and a 100 year old front axle construction. But the Aero 8 is completely different from it.

The wood frame bit is particularly amusing. Even the Ford Model T had a vanadium steel frame, if I'm not mistaken. I think you're right, though. I have read that about the Morgans.

[theSnail .@y]

Yesterday we had another round of GT4 races - Alphonse hosting 10 to 12 racers most of the time.
Now we are accustomed to the cars, the differences are more visible than some weeks ago, when we thought they were pretty equal. Well, they do not seems to be.
This morning I made some tests on Quarter Mile Test, Runway Mile Test and Bonneville Salt Flats with the 5 GT4s available.
I wrote the performances (best out of 3 runs for 1/4 and 1 mile - only 1 run for Salt Flats) and computed some statistics each time (time and top speed). The best performance received a 5 and the worst a 1. In case the cars were equally placed, I gave an average score to the 2 cars.

Results :
Nissan and Cadillac got similar results (25 and 24 points) - which was what I supposed it would be.
BMW M Coupe is not far behind (19.5 points)
BMW Z4 M and Porsche 968 have similar results too (11 and 10.5 points).
I think the Z4 could be between the M and 968 with a better gear box (the 6th is unusable).

Edit : I realised that the salt flats test is not really usefull because those cars reach their top speed after a long time (more than 1 minute for most of them). So, if we take into account the 1/4 mile and mile tests :
Cadillac, BMW M Coupe and Nissan got similar results (16 - 15.5 and 15 points)
BMW Z4 got 9 points and Porsche 968 4.5 points.


Those tests do not hold the absolute truth, but I do not think they're surprising and stick pretty well to what I experienced driving those 5 cars around (but engine sound is a subjective element that sometimes makes me think a car is faster or slower than it is ).

What do we do ?
Try to reach the top (more thrill) or the bottom ?
I have not found much real life stats about this (only that 1/4 mile in 12'2 seems to be ok - only the M coupe is able to do that in RL), so I have no idea how those cars should behave ...
We have several years of real stats of GT4 championship, but this is real life (they're more prudent than we are) and racing stats (mecanical problems, traffic, weather ...) so it's hard to compare.

[Tuktuk]

(but engine sound is a subjective element that sometimes makes me think a car is faster or slower than it is ).

Of course.
For me the most important thing is the handling. E.g. I hate the GT3 Corvette but love the Nissan. The Corvette has a terrible behavior while turning, GT4 Nissan feels light as a feather ...

I drove all GT4's and since that time I stayed at Nissan – same with TCC, always Seat ... With one of the GT4-BMW's I got better lap times on HSL but I don't "like" them.

[theSnail .@y]

I agree, but handling is a secondary issue for the moment - this is more a matter of suspensions, dimensions, center of gravity ... Right now we need a coherent class in matters like top speed, acceleration ... and I think this can be achieved with simple test tracks - where handling has no importance.

In fact the GT4 I'm more at ease with is the Caddy
And the one I still can not seem to be able to drive properly is the Z4
Of course, the one I drive the most and thus the car I'm the fastest with is the Nissan.

In TCCs, I must admit that the Volvo has always been my favorite because I'm having fun with it - even in its previous release (and its treacherous brakes). To me, fun is the most important element to choose a car

[alphonse]

The races showed in fact that the cars are not that equal.
If you use anything else than nissan you need much luck and a really nice run to beat em all

How to solve it? I am sure some of you know how - as we had a great result for the tcc's.
I loose one second on nissans times a lap on small tracks with the z4 (which is 2nd fastest for me).
I like the caddy most - but its hard when the nissan just accelerates so fast when you are next to one

Giddy up - i smell good fun for this class!

alf

[Tomte]

thanks you all for the comments, much appreciated.
Top speed is indeed meaningless, cause we cannot reach it on any track, but the way the cars accelerate is somewhat important.
Still, we have different engine configurations here, one of the things which sets GT4 apart from the TCC cars. The Caddy with its rather low rev high torque, the high revving 6 cylinder BMW's and the 350Z where the torque arrives somewhere at the top end. And then there is the odd job, the 968 turbo: least power, most torque and a very low rev range.
Leaving the 968 out of the equation for now, we should concentrate on the remaining 3. I have no problem using the 350Z as a benchmark and to slightly accelerate the rest of the cars. There is always room to play with weight or FAR.

Once the straight line performance is similar, it should be the handling which should make the difference, hopefully accommodating different driving styles.

I'll look into that in the next couple of days.

[theSnail .@y]

I like the caddy most - but its hard when the nissan just accelerates so fast when you are next to one

Just some numbers :

Quarter Mile Test / Runway Mile Test
M Coupe .. 12'29 / 30'30
Z4 .......... 12'38 / 30'45
XLR ........ 12'38 / 30'05
350z ....... 12'42 / 30'04
968 ......... 12'48 / 30'69

On 1/4 mile, 350z is beaten by 3 cars.
On 1 mile, 350z and XLR are nearly equal. It's true that on a long straight, 350z beats most of the other cars. That's what needs to be corrected

[slow]

Let me start by saying that this is a promising class of cars for fun races, and I am thankful for the hard work.
I have been using the BMW M Coupe mostly.
One thing that I have noticed in mp races, with these cars, is the lack of slip-stream from the Nissan.
It could be my imagination but, is there anything else that could be contributing to this?
Is it that much faster that I would not be able to stay in its draft?
Thanks again for the effort. slow

[theSnail .@y]

Yes, I think so.
As it is, the difference on long a straight is so great that the Z4 does not catch up.
We noticed that on Mugello for instance. At the beginning of the straight the cars seem to accelerate the same way but after a while the 305z keeps on accelerating at a good rate while the Z4 is on a lower rate - even in the slipstream.
To test the slipstream we could get many nissans on Brookland and see what we get … today 20:00 utc ?

[Toad]

The two best cars for me are the Z4 and Nissan. My "feelings" comparing the Z4 and the Nissan are that both cars oversteer quite a bit, (that's OK for the group) but the Nissan seems to be a little more forgiving entering turns and carrying good exit speed. Is that better balance front to rear, or softer suspension, I don't know. The Z4 has somewhat more precise steering input than the Nissan (car goes where you point it more predictably) but, while it turns in well, keeping it's rear end in is very much harder than the Nissan. It loses a lot of time for me for that reason, either I have to brake earlier to get a smooth entry (slower) or risk scrubbing off too much speed on mid turn (also slower) that the car can't get back on exit. Both effects give the edge to the Nissan. If the BMW could be tuned to not be so loose in the rear, possibly it could compete with the Nissan without any HP adjustments.

Driving with a Momo with no brake or throttle assists on.

[T5]

and a Morgan Aero 8 Donkervoort replacement. The rear wings will have to go, of course.

ahhh yes a Donkervoort, finally a Dutch car in RL

[Tuktuk]

There is mostly lots of confusing in MP games while searching the cars ...

E.g. a garage for all cars in post no 1 or so could be helpful ...

[Tomte]

E.g. a garage for all cars in post no 1 or so could be helpful ...

Done.

[Tomte]

One thing that I have noticed in mp races, with these cars, is the lack of slip-stream from the Nissan.

I had a look at the .car file of the Z4 and the 350z. Not much magic involved with regards to the slipstream. The Z4 has a higher air resistance: 0.76 to 0.70 (I used the value Andreu chose for he road version), the 350z has a tad more power and revs just a bit higher, also has a bit more torque. The gearbox of the 350z is also a bit shorter.
Due to the high weight of the Nissan, the quarter mile times are not the best in class. Let's take the acceleration figures and include power, torque and FAR

Car	144 mile	1 mile	weight	power	weight/power	torque	weight/torque	Air Resistance
M Coupe	12'29	30'30	1250	260	4.81	360	3.47	0.68
Z4	12'38	30'45	1300	280	4.64	375	3.46	0.76
XLR	12'38	30'05	1465	321	4.56	470	3.12	0.695
350z	12'42	30'04	1400	287	4.88	390	3.59	0.70
968	12'48	30'69	1330	253	5.26	500	2.66	0.63

Ok, now what does that mean... 1st, I don't want that all cars accelerate exactly the same. Nevertheless, I can

• drop the far of the Z4
  
• give the M Coupe more power
  
• give the 968 more power
  

Like that, the M Coupe will be the quickest accelerating car of the bunch. But it's supposed to have a more difficult handling. The 968 can't use all its torque because it revs like a tractor.

I'll look at the handling of the Z4 when I get round to it. Still, my basic idea what that the different straight line capabilities should be balanced with the handling, i.e. I don't want to have a car that is good in both respects.

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