lower emphasis/gravity of motor and gearbox???

[Tom Sch]

hello,

i am driving a '73er RS Clone with a 915 gearbox and a 3.0 SC engine.



after some tuning and modifying i have now the question if it is possible to lower the engine and the gearbox to get a better/lower emphasis

any ideas/experiences if this is possible?

thanks

[Wil Ferch]

Beautiful stunning car !!

The "flat" engine configuration ( horizontal boxer motor) already has a low center-of-gravity and the dry sump oil system does not use a deep bottom sump. This also contributes to a lower center-of-gravity.

I don't think you can go much lower unless you use a multi-plate, smaller diameter clutch pack...like the Carrera GT ( CGT), which then allows the engine/trans to sit even lower.

I also don't think you'd "feel" much difference with whatever small amount of change you can make. Maybe lower the overall car ride-height a small amount ( 12-25mm )? ...instead?

- Wil

[Tom Sch]

thanks for your argument!

it is not possible to lower the ride-height anymore. at the moment i have about 8cm (3.15") clearance, this is low enough for a streetlegal car

i have also tried to reduce the weight of the complete car as much as possible - at the moment the weight is 915kg (2017 pound) and i have no furthermore ideas for more reduction

therefore i am now looking for smaller steps to improve the performance...

if you want to see more infos about my car please look here!

[Bill Verburg]

You've done about all theat can resonably be done. Go out and enjoy it/

Very nice!

[Wil Ferch]

Du hast ein sehr schönes Auto. Es gibt nicht viel mehr, das du tun kannst, um Leistung zu verbessern. Z.B...Du kannst steifere Torsion Stäbe oder klebrigere Gummireifen benutzen.

Alles Beste,
- Wil

[randywebb]

I agree, if you want to do unreasonable things, then search on light & weight. You'll find lots of threads with speculation & etc.

A 911 racer can be gotten down to 1,700 lbs. if you spend enough money to buy a new Cayman S.

If you were will to spend enough money to buy a new C-GT, you could do even more unreasonable things.

[Tom Sch]

Originally posted by Wil Ferch
Du hast ein sehr schönes Auto. Es gibt nicht viel mehr, das du tun kannst, um Leistung zu verbessern. Z.B...Du kannst steifere Torsion Stäbe oder klebrigere Gummireifen benutzen.

Alles Beste,
- Wil

hey, i try desperate writing in english and you answer in german

torsion and sway bars are modified, at track events i use yokohama sport tires on BBS rims.

the theme with lowering the motor and gearbox to bring the emphasis down is the "newest" idea - born during a trackday...

[Don Plumley]

Nice car. Where in Bavaria are you?

Though not lower, some folks have moved the engine forward to improve handling. Something to consider.

Don

[Grady Clay]

Tom,

Willkommen zum Pelikan-Forum. Du findest Lose
Hilfe hier. Dein Englisch ist sehr gut.
Du hast schöne 911. Gute Obacht des Nehmens von ihr.

Einige Sachen, die du tun kannst:
Das Maschine Zinn mit Wiedereinbau des Fiberglases (GRP)
wie dem RSR ersetzen.
Die Brennstoffsystemteile (elektrische Pumpe und Filter) auf
den vorderen Querträger verschieben, um das Gewicht nach
unten zu bewegen und nachzuschicken.
Abblasdämpfer schwanken viel in Gewicht.
Du kannst findest einen Leichtgewichtler mit der gleichen
Funktion und Ton.
Du kannst Bohrungen in deinem Motorlagerquerträger wie
dem RSR schneiden.
Einige Leute setzen ihre Aufhebungmontageposition um
und senken die 911 soviel, daß die Maschine in die
Rückseite ANGEHOBEN WERDEN muß.

Wenn du die äußere Ventilatorriemenscheibe Hälfte bis eine
ohne den Luftpumperiemen änderst, ist es heller und
einfacher, den Ventilatorriemen anzubringen.

Extremer kannst du das 3.0SC gegen ein 2.8 RSR mit den
Magnesiumkurbelkasten- und -titanteilen austauschen.
Das 3.0SC für die Emissionprüfung verwenden.

Beste Wünsche,
Grady


Tom,

Welcome to the Pelican Forum. You will find
lots of help here.
Your English is very good.

You have a beautiful 911. Take good care of it.

A few things you can do:
Replace the engine tin with fiberglass (GRP) replacement
like the RSR.
Move the fuel system parts (electric pump and filter) to the
front crossmember to move the weight down and forward.
Mufflers vary a lot in weight. You may be able to find a
lightweight with the same function and sound.
You can cut holes in your engine mount crossmember like
the RSR.

Some people reposition their suspension mounting location
and lower the 911 so much that the engine must be RAISED
in the back.

If you change the outer fan pulley half to one without the
air pump belt, it is lighter and easier to install the fan belt.

More extreme you can exchange the 3.0SC for a 2.8 RSR with
the magnesium crankcase and titanium parts. Use the 3.0SC
for emissions testing.

Best wishes,
Grady


We need a good German –English and English-German translator
with all the Porsche technical terms and parts in the dictionary.
This was done with
Google Translate.

Best,
Grady

[randywebb]

Mufflers vary a lot in weight. You may be able to find a
lightweight with the same function and sound.
- M&K seems lightest, followed by the Monty
(also use headers & not heat exchangers)

You can cut holes in your engine mount crossmember like
the RSR.
- no real wt. savings, but I did it for the looks...

also - the engine grill is about 2 lbs. whether metal or plastic - an R type grill can save a bit.

visit rennlist.com (Thom's web page) or the Rgruppe site - both have copies of my wt savings database.

The Excellence article on Jim Calzias car is cited there - that is a good how to on building a light wt. race car.

[Jack Olsen]

You can move the engine and transaxle forward almost an inch and a half to improve front-rear weight distribution.

Lexan windows and replacing the roof (and B and C pillars) with the carbon fiber kit made for cabriolets will lower your center of gravity.

[azasadny]

Beautiful car!!!

[jpahemi]

Upside down gearbox??

[Tom Sch]

hello,

@Jack
is it necessary to weld the mounting points at a new location if i want to move the motor/gearbox forward? or is there any special part/adapter available?

@Randy
whats the nickname of Jim Calzias at the forum? if i use the search i cant find anything under his real name...


now i am on the way in the garage to change the engine/gearbox mounts (to stiffer ones from pelicanparts ) and maybe install a fuel distributor from MaxMoritz to fight against lean fuel. we will see...

Tom

[randywebb]

Tom - I don't think Jim posts on any boards much. He recently repainted his car and posted on that, maybe it was the Early 911s bbs. I'll post some reading for you below. I'd do that first, then go look at Jim's wt. table (it got left out of the Excelence article on his car) which is posted at their web site.

I don't read German so couldn't tell what exactly you've done so far, but you are getting into the areas where wt. reductions entail real compromises. But they can still be done -- and people here would love to help and kibbitz if you go further.

You also want to look at Thom's car and his web site, rennliight.com - some of my info is posted there, incl. a more thorough table of wt.s for various things. Mine is oriented towards early cars, but also towards making a lighter street car
(Yet Another Boring Hot Rod Rgruppe Car - Part V, Exterior & Paint)

But you are already beyond that.

OK, here is reading info:
Other Notable Cars
Black Beauty II Jack Olson car – modified 1972 911 with 3.6L 964 engine (only mods are the B&B exhaust and the NBD chip); 2,389 lbs. with 243 hp at rear wheels; wt. distribution, F/R 39/61; torque tube cut and engine shifted forward 1.25” for wt. balance; very wide flares, has A/C, carpet, and some ext. trim; prepared by Tyson Schmidt (TRE Motorsports); Goal was to combine high grip of wide tired RSR type cars with nimble handling of narrower RS cars; LRX custom F. spindles, front A-arms have been lengthened by about 1 1/3 inches and mounting points have also been changed; Hamlin Fabrication R. camber boxes that modify the mounting points for non-turbo 911 pivot boxes to allow easy at-track camber and roll center adjustment (cheaper than 930 trailing arms). Also claimed to dramatically improve rear suspension geometry to decrease squat tendencies, accommodate very low ride heights but no change to toe settings. R. Bilstein coil-overs and 935 type spring plates. Tyson tied the center tunnel in with the torque tube, and added diagonal braces between the inner rockers and the center tunnel, which no doubt help as well. Excellence # 125, December 2003; and Pelican Forum threads: Excellence magazine arrived today. BB2 -- Jack/Tyson/other Evil members
Tangerine Freeman Thomas 1969 911 R type clone; Excellence #132, October 2004, p. 129; 2,200 lbs., 280 hp 2.8L, many interesting details but little wt. information on this sports purpose ’69 car
Yellow car prepared by Jeff Gamroth (RothSport); article in Excellence #120, June 2003; 3.7L with variocam, 2,250 lb.
Retro Rocket red RSR Clone – 1,750 lbs (794 kg) with 962 engine and “upside down” 935 turbo trans., making it the lightest known clone – even lighter than a 911 R – even though it has larger fenders and a roll cage; article in Panorama, Dec. 2004, but few details

Sources and Additional Reading
Gruber, Thomas and Georg Konradsheim. 1992. CARRERA RS. Hdbd., limited ed. in slipcase, 255 pgs., 122 black & white illustrations. -- not avail. in US libraries – OCLC checked in 2003
Adler, Dennis. 1998. PORSCHE 911 ROAD CARS. MBI Publishers.
Adler, Dennis. 2003. Porsche: The Road from Zuffenhausen. Random House. NY, NY.
Leffingwell, Randy. 1997. ILLUSTRATED PORSCHE 911 BUYER’S GUIDE. MBI Publishers. 4th ed. revised and updated version of Dean Batchelor’s book.
Ludvigsen, Karl E. 1977. PORSCHE: EXCELLENCE WAS EXPECTED: THE COMPLETE HISTORY OF THE SPORTS AND RACING CARS. Princeton Publ.; New York, NY; distributed by Dutton, 851 pages, 1st ed. {citations above are to this 1st ed. as I haven’t read the 2nd ed. yet).
Reisser, Sylvain. PORSCHE. page 101 – tidbits on the RS.
Starkey, John. PORSCHE 911 R-RS-RSR. – comprehensive source (Larousse Tour d’France car was a further modified version of a Steinemann 1970 Group 4 car, p. 14-16) – same book as below??:
Starkey, John. 1987. THE RACING PORSCHES, R TO RSR. Sparkford, Somerset; Newbury Park, Calif.; Haynes Publ. Group.

Excellence # 22 - articles covering the R, RS, RSR and ST
Excellence # 31: 88-90, February 1992. 911’s “R” Us, David Colman.
Excellence # 33: 50-53, June 1992 – The Porsche 911 R , Kerry Morse
Excellence # 34: 88- 91, August 1992 – “R” Stands for Rare, David Colman
Excellence # 47: 96-101, August 1994 – restoring an RS for Manhattan Concours Award, David Colman
Excellence # 68: 69-74, April 1997 – Carrera RS & RSR, Part 1 of 2 – John Starkey on the RS and 2.8L RSR
Excellence # 69: 97-104, May 1997 – Carrera RS & RSR, Part 2 of 2 – John Starkey on the IROC and 3.0L RSRs
Excellence # 69: 86-90, May 1997 – Carrera RS Replica – standard changes
Excellence # 80: 124-28, October 1998 – French Connection – Dave Morse’s 911 S-T by Bruce Anderson
Excellence # 101, May 2001 – Jim Calzia's lightweight race car with weights of various components and modifications – more detailed data on the Early 911s web site at http://www.early911sregistry.org/jCalzia.html
Excellence # 110: 56-65, May 2000?? – Pete Stout compares the 2002?? GT2 with the 1973 Carrera RS.
Excellence # 125: 108-114, December 2003 – Jack Olsen’s Black Beauty II
Excellence # 123: 94-98, October 2003 – GrantG’s Carbon Copy car; see also various posts and photos on the Early 911 web site
Excellence #132: 129-134, October 2004 – Tangerine Freeman Thomas 1969 911 R type clone
UpFixin' VII, p. 356 - SC/RS and some history of the "R" cars
Motor Sport, Feb. 1973 – Denis Jenkinson tests an RS
Panorama, June 2001, p. 2 - pristine 911 RSR
Panorama, ?? August 1985, p. 9. P. Kelly – article on SC/RS
Panorama 49(12): 2-10, December 2004 – Retro Rocket - 911 RSR
Road Test, April 1973 – Jerry Sloninger tests a RS light weight
911 & Porsche World, April 2003, No. 109 – several articles on lightweight 911s

[Bill Verburg]

Llike I said "reasonably"

[randywebb]

That word is defined differently in Pelican Land...

[Grady Clay]

Randy,

I used Google Translate to read Tom's German link. The translation is pretty poor but still readable. A torsion bar is a something post.

Are there some freeware translation programs where you can load a personal dictionairy?

Best,
Grady

[Wil Ferch]

Grady:
I only recenty saw your personal PM to me...couldn't reach you "in time"..see other post asking for you.

- Wil

[Tom Sch]

hello,

all agog with curiosity i have tried "google translate" to translate my link - funny output

thanks for the ideas and links for weight saving, many to read, something to do

Tom