GT1/DTM Performance Differnce

[SALEEN S7R]

I was just looking around this morning and I noticed times posted on www.lmsr.net for the 2005 testing at Spa Francochamps. Here are the leading times.

1. Heinz-Harald Frentzen Opel Vectra GTS V8 2:14.312 Min. 26 Rd.
2. Jamie Green AMG-Mercedes C-Klasse 2:14.701 Min. 36 Rd.
3. Jean Alesi AMG-Mercedes C-Klasse 2:14.721 Min. 77 Rd.
4. Stefan Mücke AMG-Mercedes C-Klasse 2:15.148 Min. 51 Rd.
5. Christian Abt Audi A4 DTM 2:15.217 Min. 50 Rd.
6. Frank Stippler Audi A4 DTM 2:15.329 Min. 53 Rd.
7. Allan McNish Audi A4 DTM 2:15.357 Min. 74 Rd.
8. Laurent Aiello Opel Vectra GTS V8 2:15.378 Min. 28 Rd.
9. Bernd Schneider AMG-Mercedes C-Klasse 2:15.454 Min. 41 Rd.
10. Bruno Spengler AMG-Mercedes C-Klasse 2:15.522 Min. 67 Rd.
11. Marcel Fässler Opel Vectra GTS V8 2:15.585 Min. 60 Rd.
12. Manuel Reuter Opel Vectra GTS V8 2:16.617 Min. 45 Rd.
13. Tom Kristensen Audi A4 DTM 2:17.720 Min. 10 Rd.
14. Pierre Kaffer Audi A4 DTM 2:18.013 Min. 15 Rd.
15. Martin Tomczyk Audi A4 DTM 2:19.371 Min. 38 Rd.

Not really any faster it would seem than the GT1 cars, last years pole postition for the Spa 24hrs was a 2:15.047. Now sure the DTM cars at the moment are slightly faster than that, but will this be the case when the FIA GT boys come back for the Spa 24hrs in the summer this year? I dont know, but its important to remember that the MC12 has since been allowed to race in the FIA GT championship since the Spa 24hrs, it will be very interesting to see what teams like Vitaphone and JMB can do with this car in 2005, my betting though is they can eek out a fair ammount of time over the 2004 cars.

[Kicking-back]

A circuit like Spa will narrow the gap, as GT cars have plenty of long straights to use their power.

A tighter track would hand the advantage to the DTM.

[SALEEN S7R]

I dont think so KB. Spa is a very twisty and technical circuit just as much as it is a fast track, the circuit is a medium speed circuit really. Its not really a high speed circuit, sure the GT1 cars have big power 600+bhp but the DTM cars too have around 500bhp, and of course are better areodynamically than the GT1 machines. Spa is a track of 2 halves, interesting to see the comparissan between the 2 kinds of cars. I agree though, at a track like Orscherslaben for example the DTM cars would be faster than the GT1 boys, but at a track like Monza and id think the opposite.

[Audi R8R]

DTM Cars are probably slightly more techinically advanced than the GT cars. There will be slightly more trickery than a GT car.

But I'd expect that the GT1 cars will have moved the goal posts on from last year's Spa times. But then, have they all got smaller restrictors this year in line with ACO regs?
In which case, they might be the same if not slower. Doubtful, but will be interesting to find out.

[gwyllion]

Originally Posted by SALEEN S7R

I dont think so KB. Spa is a very twisty and technical circuit just as much as it is a fast track, the circuit is a medium speed circuit really. Its not really a high speed circuit, sure the GT1 cars have big power 600+bhp but the DTM cars too have around 500bhp, and of course are better areodynamically than the GT1 machines.

DTM cars only have 470 hp for the same weight (around 1100 kg).

And DTM cars all use the same control tyre from Dunlop, which is very narrow compared to GT1 cars:
* DTM cars: 265/660-18 in front, 280/660-18 rear
* FIA GT1 regulation: maximum width is 14" = 355 cm

[SALEEN S7R]

No DTM cars have closer to 500bhp this year than 470bhp, last year it was around 470bhp for most of the cars but the Mercedes had around 485bhp by the end of the year. Audi R8R, yes the FIA GT, GT1 cars now do have to comply with the ACO GT1 regulations, which explains in part, of course why the cars were 5 tenths slower than the 2004 pole time at Monza, the other reason being due to weather conditions I would imagine. Now bearing in mind development throughout the season I personally would imagine that the cars would be going faster than the 2004 cars, particulary by mid season the Spa 24hrs is due. It will be very interesting to see what is ultimately faster at Spa, personally im going for the GT1 cars, albeit marginally.

[courageous]

Surely the GT1 cars would be running in a slightly more conservetive spec for a 24 hour race than for a 2-3 hour race. Any comparisons for lap times in a normal weekend?

[Jeffrey-Lee]

Hockenheim 2004
Fia GT-Lechner Jr/Seiler/Konrad Saleen S7 1:37.132
DTM-Jean Alesi Mercedes C-Klasse 1:35.010

Oschersleben 2004
Fia GT-Lechner Jr/Seiler/Konrad Saleen S7 1:23.543
DTM-Mattias Ekstrom Audi A4 DTM 1:20.471

DTM cars with the better aerodynamics and downforce are faster, a thing more apparent at the twisty tracks like Oschersleben than a fast track like Spa.

[Audi R8R]

Don't DTM run with traction control too?

That'd help out of the twists too I guess.

[JAG]

Originally Posted by Audi R8R

Don't DTM run with traction control too?

That'd help out of the twists too I guess.

ACO GT1 cars also have TC and of course the FIA cars will have it this year.

As was pointed out, the DTM cars are sprint machines.

When endurance spec cars ran in the Nurburgring 24 hours they were only a second or 2 quicker than privateer 911 GT3 RSRs, and the M3 GTR V8s qualified right in the middle of the DTM pack.

[SALEEN S7R]

Im not sure where exactly in the ACO regulations it is written, but I am certain that I have seen that traction control is allowed too in LM GT1 and LM GT2, at least it was in 2004. Honestly, with the new generation of GT1 cars, like the C6R, DBR9 and MC12 I dont think it will be long until the GT1 cars are faster than the DTM machines at every circuit, as for Spa being a high speed circuit, can someone tell me how people are reaching this conclusion? The track is a medium speed circuit with a couple of long fast straights. Its certainly no Le Mans or Monza. If tracks like Catalunya are considered medium speed tracks, I dont see why Spa woudnt be, both tracks are very similar.

[Mal]

Is there a comparison between the LMES GT1 and FIA GT1 anywhere. On the evidence of Sebring and the Maserati, I would say that the 'works' LMES / ALMS cars are faster - but then of course the MC12 was restricted and modified from last years FIA car. Is there a better comparison

[JAG]

Whats the latest on the ACO's plans to restrict the performance of GT1 cars that lap quicker than 3.52 at L e Mans (which will be everyone I would imagine).

Has this now been dropped, ala the white line rules?

Would these changes apply to FIA GT, or are they simply the ACOs version of the ballest system in FIA GT.

[flor]

Originally Posted by SALEEN S7R

Its certainly no Le Mans or Monza.

true, but for example its nearly flat out from la source to les combes and that alone is 1/3 of the track and also from Stavelot to Bus stop is very fast

[gwyllion]

BTW Pierre Kaffer did 2:13.689 today.

[TheNewBob]

The GT1 cars would probably not be running in endurance spec too much during qualifying... would they? I've never seen an FIA GT qualifying session so don't know how they'e run

[Silk Cut Jaguar]

Like mentioned above, it's all in the cornering speeds. DTM cars are more like F1 cars in just how flat and stable they stay when turning at speed.

[JAG]

Originally Posted by TheNewBob

The GT1 cars would probably not be running in endurance spec too much during qualifying... would they? I've never seen an FIA GT qualifying session so don't know how they'e run

The DTM 24hrs cars were built from the ground up with much stronger components to last the distance. The sprint cars are much lighter so ballast can be moved around.

[TheNewBob]

OK, thanks for that. I didn't know they built DTM cars to 24 hour regs, for any reason other than the Nurburgring 24 hours.

[lj79]

[QUOTE=SALEEN S7R], as for Spa being a high speed circuit, can someone tell me how people are reaching this conclusion? QUOTE]

It is, it's just that Monza is extremely high speed. Compare fastest lap speeds at all the circuits visited by the FIA cars in 2004.

Monza - 124mph
Valencia - 97mph
Magny C - 100mph
Hockenheim - 104mph
Brno - 101mph
Donington - 102mph
Spa - 114mph
Imola - 103mph
Oschersleben - 97mph
Dubai - 103mph
Zhuhai - 104mph

All speeds are rounded up if>0.5mph and down if<0.5mph

In addition - you need to include in the "two straights" the whole of the run from La Source to Les Combes - well over a mile - just a slight lift (M3 GTR) or a gentle squeeze of the middle pedal (others) for Eau Rouge, plus the run to Les Combes up the Kemmel Straight (Saleen - this is the bit you call the "Camel" Straight) is uphill where lots of torque is needed.

Similarly the run from Stavelot to the Bus Stop is uphill all the way, albeit not as steep as the run to Les Combes.

Rivage all the way through Pouhon is quick too - in fact, the exit of Pouhon is a fine place to watch the cars - really getting some serious speed.

There are lies, lies and damn statistics. Thus conclusion, with notes on how people reach it: Spa = a high speed power circuit.

And, as there was no Barcelona race in 2004, the 2003 FL at this circuit was 101mph. Further proof that Spa is high speed.

I would advise you to go one day, and see for yourself.

[Adam43]

FWIW in such a discussion that is all about degrees and hence has no definitive answer I have a little experience in Spa compared to other circuits.

I think lj79 has the balance right. Yes Monza is more 'high speed', but that can be classed as extreme. Spa, compared to most circuits, is generally high speed.

When I've raced there, in a relatively high power and big car, I've found that lighter and less powerful cars which were quicker round a 'normal' track were slower round Spa. This was down to the power down the straights and the the longer wheelbase through the really quick corners (Eau Rouge, Pouhon, Blanchimont, etc).

I think it is a fair assumption that Spa inherently has more of an advantage to GT cars than DTM cars (even considering the colt on aero of DTM). The power and the wheelbase/sportscarness of GT should really work at places like Spa. That is the idea behind those cars! That makes the lap times of the DTM cars very impressive.