Just Another RSR Rep !!!

[johndglynn]

Now amended to include the quote :

"2.5 times quicker at overtaking than any other 911" - johndglynn

I do like a good testimonial :D

[IanMcLeod]

... I've always thought that to be able to call a car an accurate and correct replica you need to incorporate the fundamental
basic elements that made the original so special in the first place, so as to be able re-create the feel and look but above all the driving experience
of the original...

+1

[brembo]

Another RHD rep......

I'm sure I read somewhere,there's an original rhd 2.8 rsr(gulf blue) in Australia,might be completely wrong.
Regards,

[964RS]

Yes there is one RHD RSR....it's the bast**d son of an illegitimate mother and deserves it's place in a firey hell

[Disco]

In the case of a 73 RSR those fundamentals are high butterfly injection, a twin dizzy and 11" rears, this car being touted as something a bit special
And therefore so expensive they can't even put a price on it, has none of those 3 elements.

Of course they are offering the dizzy and wheels, if you want to pay a shed load more.........: roll:

Mike,

I'm not purporting to know anything about RSR's other than the fact that they look lovely but I think its a tad bit harsh to bash PS for having a car up for sale at POA. - Many dealers and private sellers do it.

In this case it makes perfect sense to me to have it POA, that way one can discuss the various options (and price tags) available to a prospective purchaser, this way a larger demographic is captured

Ie Mr. loadsamoney can have the dizzi and wheels and Mr. itlooksthepart can make do without and maybe buy a garage to keep it in with the money saved.

I did read a post on here by someone that mentioned that the price of replica RSR's and RS's had devalued due to the numerous poor quality versions now available but ultimately one tries to buy the best car that they can afford at the best price.

To explain in an analogy, it is said that it is better to buy the worst house in the best road rather than the best house in the worst road...

of course, and this is where your RSR project comes into play - ideally you'd buy the best house in the best road, but only a few people are truly ever in this position.

cheers!

Disco

[Mike Usiskin]

or get a cardboard box and spend the rest on Porsche's!
m

[Sam]

In the case of a 73 RSR those fundamentals are high butterfly injection

Happy to be shot down for my newbie ignorance, but I'm sure I've seen at least one historic racer on slides - were those not homologated too?

[Mike Usiskin]

Mike, can I ask re butterflies etc? what is the advantages of high butterflies? why did they use them? Are they any use on a 'normal' 911 and if so do many folk use them? seriously now ppl

I suppose the question is what makes the RSR engine So potent, it's not just cams etc I assume.

mucky love one and all

M

[PhilipB]

In the case of a 73 RSR those fundamentals are high butterfly injection

Happy to be shot down for my newbie ignorance, but I'm sure I've seen at least one historic racer on slides - were those not homologated too?

Slides weren't used on the 2.8 RSR. They were used on the 3.0 RSR of 1974. However some factory cars and favoured customers got the 3.0 motor in their "2.8" in 1973. For historic racing I think you'd get away with them (and the bigger motor for that matter).

As to what makes an RSR engine more powerful I think the answer is a bit more of everything - compression, timing, capacity, valve / port size, fuel flow, rev limit etc.

[Lightweight_911]

Slide-valve injection wasn't used on the 2.8 RSR - it was introduced early on in the production of the '74 3.0 RSR.

It had been used in other Porsche racing engines though - such as the 906E.

[Lightweight_911]

... - too slow !

[Lightweight_911]

As for why was 'high butterfly' injection used, it's similar to why tall inlet manifolds were used with the 46 IDA Webers on the 911R, 906, etc:

- engines with more aggressive cams like 906/RSR which have lots of overlap can suffer from fuel reversion at low & medium revs caused by pulses up the intake which hit a certain resonance, creating a cloud of fuel droplets floating above the mouth of the carb.

By making the intake track longer the frequency of the intake pulses no longer matches that resonance and so the cloud disappears - at higher revs this tends not to be a problem since the air/fuel mixture is traveling at a higher speed into the cylinders.

[squirdan]

i just think you've got to differentiate between a 100% period correct "replica" and an "evocation" which is probably designed more for usability.

theres nothing wrong with either route...just different compromises

an example is rear tyre width. 9inch is ample...anything more is probably over-tyred to detriment of handling balance

brand new custom made wiring loom and dash from Tuthill = no electric issues ever again / but wont win prizes for historic looks

to my mind this car strikes q a good balance between modern technology and period charm

[Mike]

As Philip and Andy have already pointed out slides weren't used on the RSR until 74.

I suppose the question is what makes the RSR engine so potent, it's not just cams etc I assume.

Mike, Andy's given a fantastic explanation of the high butterfly and how it works, what he didn't mention is that they look fantastic as well!

As for what makes the 73 RSR motor so potent, I think it's best to think of it in terms of taking the 2.7 mfi engine which as we all know is
the most fantastic 911 engine for power and throttle response, then tweeking everything you can to increase the horse power and performance
even more.

Larger bore to 2.8 or 3.0 in the case of the 'werks' cars, then high butterflies to feed the air to mix with the fuel from the highly modified injection
pump. The fuel/air vapour is sucked in through enormous 43mm ports into relatively small combustion chambers because of the high domed
pistons which give it the high compression. Because of those high domes you twin plug the heads so the mix ignites across the top of the piston
evenly. On the way back up the burnt gasses are forced out through again huge 43mm exhaust ports into large bore headers, this is where you are
gaining a lot of horse power but losing torque which makes for the peaky nature of the RSR. The oil fed high profile cams are working here with the
valve overlap helping the flow of gasses between ports, but making for a lumpy idle.

Everything is lightened, balanced and measured to make this action as free flowing as possible, which together with the use of parts like solid
rockers, large oil pump and extra oilways for durability, lets the engine run to a higher rev limit and gives you the incredible power and performance.

HTH

[Nick Moss]

Another one! Click picture for more details



This particular car is a 1971 911 model with extensive modifications to engine, chassis and body to bring it up to RSR specification. It uses many original RSR parts, and is finished in striking Martini Livery.