Whats the true output of a GT3 Porsche engine?

Megatron · 2 Sep 2003, 19:25 (Ref:705984)

In an interview, Roger E from Grand Am suggested that a GT3 Porsche engine unrestricted produced about 500 horsepower. Hurley Haywood has been quoted as saying it is around 485, while during the 24 the TV commentators said it was about 460.

What is the approximate output of a GT3RS engine with no restrictor?

rdjones · 2 Sep 2003, 19:34 (Ref:705996)

Just been checking a couple of ALMS sites and it runs to about 420Bhp

panoz.lmp1 · 2 Sep 2003, 20:00 (Ref:706025)

There are unofficals infos that the Freisinger 996GT3-RS are runing with 480hp.

The hp without restricotrs? A lot more than the 480??? ;-)

paul-collins · 2 Sep 2003, 20:20 (Ref:706046)

ALMS and Le Mans Porsches are restricted, mind.

**PascaLM** · 2 Sep 2003, 20:59 (Ref:706096)

It depends on restrictors (460hp); It may reach 480hp without them.

Karl Kling · 3 Sep 2003, 00:26 (Ref:706289)

From what i've heard the maximum power you can squeeze out of an unrestricted GT3RS engine without turbo is about 480 hp.

The new GT3 (the road legal one) has a slightly revised engine and can perhaps have a little higher power limit when it turns into the new GT3RS expected next year. But that's just my speculations...

**skycafe** · 3 Sep 2003, 00:37 (Ref:706296)

I read somewhere (can't remember where) that the GT3RS had about 30 horsepower on the Modena, and the Modena is quoted in Racecar Engineering at being at 430, so 430+30=460 ???

By-the-way, since the GT3RS is a core engine in the GrandAm Daytona Prototype program, and if the engine maxes around 480+ horsepower, don't expect the wish for Daytona Prototypes to end up with any great power boost. The Fords and Chevys may have that potential, but the Porsche would not...

**Dani Filth** · 3 Sep 2003, 10:19 (Ref:706651)

the new road spec GT3 is around 380 .. so maybe the RS is about 440-460 .. the Modena is in road spec 400 .. so the impovement in the race cars are small .. could change with the new V8 in the folowing years ..

C_g · 3 Sep 2003, 16:14 (Ref:707093)

In 2001, the figure was about 450bhp I heard. I expect they've made gains since then in power (decreasing internal losses) and drivability, so 460bhp doesn't sound absurd. Apparently the restrictor cut for this year didn't affect them at all. Is this due to the fact that they aren't maximizing flow through the restrictors in the first place? The GT3RS doesn't have ram ducts like the M3 GTR did.

**skycafe** · 7 Sep 2003, 03:12 (Ref:710542)

C_g, I think you are correct about restrictors, the article in Racecar Engineering mentions that the GT3 airbox isn't very effecient so that decreased size in restrictors mostly just raised torque, and the drivers found it more drivable, hence no effect on lap times. The ineffeciency in the airbox isn't described, but I would say you are correct in that there probably is little ram air effect.

**Dani Filth** · 24 Sep 2003, 07:30 (Ref:728421)

FOR THE UPCOMING racing season Porsche Motorsport presents the 911 GT3 RSR. This near-standard racing sportscar aims to keep private customer teams competitive in international Gran Turismo sport and to continue the success of the predecessor model which won its class at the Le Mans 24 Hours five times in succession, became a record and title winner in the American Le Mans Series as well as the FIA GT Championship, and secured the overall win at this year's Daytona 24 Hour race.

Based on the new road-going 911 GT3 RS, a particularly light and sporty version of the 911 which was presented to the public at the Frankfurt Motor Show (IAA), the GT3 RSR features improvements to its predecessor in all key areas. The vehicle is available in an ACO (Automobile Club de l`Ouest) version for competing in Le Mans and in the American Le Mans Series as well as in a FIA specification.

The 911 GT3 RSR features a modified front which improves downforce at the front axle.

The 3.6-litre, six-cylinder boxer engine delivers 445 hp at 8,250 revs. Maximum torque is now 405 Nm at 7,200 rpm, with top revs reached at 8,500 (for the FIA specification with two 30.8 mm air restrictors). New pistons and rods as well as a new valve gear result in a moderate power increase with the focus on further-improved driveability and durability. A characteristic feature of the new RSR is its air-inlet which generates ram pressure.

A six speed sequential gearbox with ignition cut ensures quick gearshifts at full throttle and offers reliable protection of the gearbox from misuse.

The racing suspension, with McPherson struts in the front and the Porsche multi-link axle at the rear, features new kinematics thanks to new wheel-uprights and modified mounting points. Further improved turning in and reduced tyre wear are the most obvious results of these modifications. The double springs adjustable to four settings, the adjustable shock absorbers and anti-roll bars as well as unibal joints ensure a precise set-up to suit each circuit.

The brake system features four-piston aluminium callipers on all four wheels with discs measuring 380 mm diameter in the front and 355 mm at the rear.

Weighing 1,100 kgs (FIA specification) or 1,115 kgs (ACO spec) the 911 GT3 RSR sits at the minimum weight limit. Porsche offers various kits for different competition purposes. Porsche Motorsport will deliver the first vehicles in December.
- 445 hp and 405 Nm
- 18 inch wheels
- Weight: 1,100 kilograms
- 279,000 Euro excluding tax

http://www.sportscartesting.com/news...e/id725/pg4162

slicktsax · 24 Sep 2003, 11:02 (Ref:728589)

ok i think the latest i heard was that the 2003 911 GT3 RS race version is officially rated at 435 horsepower. and since the airbox is inefficient the smaller restrictors didn't hurt the porsche at all basically so porsche was easily able to increase the power output. where as the ferrari 360gt was hurt pretty badly and lost like 30 horsepower. Team Maranello Consessionaries is working with the ferrari factory on a new evolution of the 360GT called the 360GTC. i don't know the details yet but i do know it should have a sequential shift not the paddle and more horsepower i believe around the same numbers as the new 911 GT3 RSR. it also should boast a revised aero package

kmchow · 24 Sep 2003, 17:19 (Ref:728905)

OTOH, unless some people are quoting 480+ for special "grenade" or qualifying engines? IE: High output engines that don't last long and/or are unreliable. But they aren't legal anywhere anymore? I've heard of people using them in the past in F1 and perhaps other racing series??

billnchristy · 24 Sep 2003, 17:47 (Ref:728933)

The GA DP engines arent restricted at all, and may in fact have a different airbox (dont know for sure) that could be where the number is coming from...also the DP is a LOT louder than the GT3 so probably has a much freer flowing exhaust as well...

SALEEN S7R · 24 Sep 2003, 17:56 (Ref:728942)

I think its worth remembering that now the Porsche produces 430bhp in race trim, but in 2004 the regulations change and the cars restrictors are 10% bigger, like in 2002. Im no good at maths so u figure out how much 10% more will make. Im guessing around 445-450bhp.

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