Steve, I'd be happy to compare either to my GT3 and file an in-depth report on how each car drives with the rest of the list

 

Steve,

For arguments sake lets forget the comparisons between the RSR and Cup cars. We are getting all side tracked about the RSR being a race car and having engine rebuild done after every race. Let's forget I mentioned the RSR and Cup cars and just focus on a throttle control valve for each cylinder like the new M5 has.

What you are telling me is that a throttle control valve for each cylinder on the GT3 motor, a system that more efficiently handles fuel/air mixtures independently for each of the 6 cylinders rather than the current system which just has one and assumingly works on an average for all 6 cylinders will do nothing to provide extra HP as it did in the 964? or in the new M5?

Or are you saying that in order to put a 6 system throttle control valve on a GT3 motor you need to do too many other changes to make it work?

 

Hi:

What I am saying is that converting a single throttle system like your GT-3 to a six-throttle intake (tall butterfly, slide-valve, or plenum) requires totally new ECU mapping and that is VERY expensive to do.

None of the above variants have any provisions for emissions-related equipment and would prevent OBD-II compliance.

That said, if one had the money to do this, the difference in throttle response is astounding.

 

What do you mean by OBD-II compliant?
Don't mean to be a hard head, but why would the ECU mapping (which is just software) be that expensive. Why could they not remap with emmissions compliance, as I am sure the M5 is.

Aren't tuners already remapping ECU's now to get that little extra out of NA and Turbo motors now with emmissions compliance?

Again FVD offers this on the 964 with remapping ECU, cams, and 6x intake.
Would the GT3 be that different?

 

RR;

There is vast differences between this engine and the 964. Variable cam timing, 4 valves per cylinder, multiple timing grids and camshaft advance/retard.. Yes, tuners are re mapping but like Steve said it is very expensive.. The only thing that the 964 and the GT3 shares in common, is the engine case, and intermediate shaft..

 

Konstantin, what is this kit and what is the 411 at which it is offered?

 

RR-- You're making this harder than it has to be. Listen to Uncle Steve. It is NOT, repeat NOT, realistic to put a single-throttle system on a U.S. street car, even with a $12,000 MoTeC engine-management system to lean out the motor for emissions. You would never pass emissions or even come close. Massive amounts of air and fuel pour down those throttle bodies. There are German tuners like FVD and Cargraphic that adapt single-throttle high-butterfly systems for the street, but I seriously doubt that any of those setups would ever clear emissions in the U.S. No ECU remap will work with a RSR engine, because you won't have an ECU--you need a MoTeC electronic fuel-injection system to handle the fuel and ignition maps and control throttle position.

Take your money and invest it in pork bellies or chocolate futures or something, OK? This won't work.

Lee in D.C.

 

Chocolate futures ... now why didn't I think of that before. Finally an investment my wife will appreciate. Now where did I put my broker's cell phone number?

Karl

 

RR:

As usual, Brother Lee spoke volumes of truth here,...

OBD-II (mandatory for all cars sold in the US since 1996) is VERY VERY complex and has many meg of code for smog compliance and drivability. To explain how it works and why its not simple to simply swap intakes and tweak the ECU would take hundreds of pages to explain in detail.

I'd be happy to give you a snapshot view if you want to call me sometime as this subject is far far bigger than you know.
Further, mapping an engine from scratch is a mega-week affair to get the full-power and all regimes of throttle positions to run as well as your stock GT-3 does.

Porsche spent millions of Euros to map these cars and make them pass emissions compliance in North America.

I do subscribe to the idea of Pork Belly futures since I am the one who,............(are ya ready?)....brings home the bacon.

Couldn't resist,...very sorry.

 

Spend £7K on the Quaffe sequential box. Direct bolt in and should knock 1/2second off your 0-60 times, sub 4 seconds anyone?

Your lap time will be decreased as you are always on the power and you can change all the ratios to suit. Bolt the original back for warrenty issues and Bob's your Uncle!

Much better than mucking around with the engine and with similair results.

Don't beleive me, go and find a sequential boxed car and feel the differance!

P.

 

Two questions please:

1) I am always hearing this "rebuild after 25 hours" thing in relation to the Cup engine. Exactly what part(s) in that engine will only last 25 hours?

2) Forget USA road emissions requirements for a moment. Let's say the car only needs to be roadworthy (i.e. reasonably drivable on the street). Now would it be possible to build up one of these engines using the various Cup, RSR, etc. parts???

Stephen

 

I will repost this as Stephen may have missed it...

I spoke recently with one of the teams running the Porsche Cup Cars here in the UK about engine rebuilds. Porsche state that the race engines need to be refreshed after 25 hours running. One of the cars they look after had just reached this so they took it apart.

Nothing needed replacing. At all. The engine was making more power now than when it was new and revved more freely.

They just bolted it back togeather and stuck it back in the car.

Therefore, it would seem reasonable that you could mod the car in the way you describe in terms of longevity.

I beleive the problem would be in drivability, RSR's etc are designed for racing, not stop start traffic conditions.

True, you could reprogramme the ECU but then I suppose it just comes down to cost.

Question is, do you really need the extra 35hp over the GT3 or would the money be better spent on good driver training?

Over too you.

P.

 

P,

Sorry, i missed that. Could you repeat it!

 

I never miss anything you say RS. But you can repeat it again if you like.

Seriously though, I'm really looking for some sort of definitive answer to the question. That one team tore down an engine and it was ok doesn’t really provide that. My own personal feeling is that the 25 hours is more about refreshing the engine than rebuilding it – i.e. an opportunity to inspect it and possibly to re-cut and re-seat the valves/seats (which might be worth a couple hp).

Ok, so what are the drivability issues? I know already that it needs some sort of cooling fan but that is not a big deal. Is this an engine that will not run below 4000 RPM? Are the cams too aggressive? I really would be surprised if this was totally un-drivable on public roads. And a car like this isn’t going to spend that much time on public roads anyway (excluding the Nürburgring during public sessions of course). Who in their right minds would commute daily in one?

Is this just about 35 hp? I don’t think so. 150 hp/litre on a 4-valve engine should be possible. But it isn’t just a matter of hp. Separate throttle bodies should be able to make for a much more instantaneous power delivery. We only have to look at how improved the 997S is on throttle response to see what might be possible.

Stephen

 

Fixed Wing;

When the ALMS cars were in Portland a few weeks back, one of the GT3RSR's lost an engine, due to the rod bolts failing. The life of these engines are about 80 hours in endurance racing. My statement includes the facat that Porsche Motorsports throws away most of the internal rotating assembly and cylinders. At the midway mark these engines get re-ringed and re-bearing.. The set of Titanium Pankl rods that I have needed to have the big end of the rods redone. They weren't distorted like many have seen. Pankl says that the Titanium rod bolts are good for only 2 torque cycles. Porsche Motorsports recommends switching over to ARP rod bolts..

You can make these engines last by reducing the RPM that you need to pull out of them. For the record my camshafts are close to .500 of lift... The GT3 cams are alot less. Running these engines at Sebring or Daytona or Lemans, will require a tear down. PCA racing or 3 hour endurance races will give you more life.. I feel that these engines can be used for the street, DE events.. I'll find out shortly, how much life I will get out of it..