Got a bit of money...what would you recommend as SC upgrades?

[twobone]

A great Aunt just left me some money and now I'm curious about what you would do in my shoes.

I live in Toronto Canada so access to good P-Car mechanics is pretty limited.

Also the resale market in Toronto is not very good and so the idea of selling my 81 SC and buying something else does not really appeal to me. I do love the 964/993 body style, but there is something about the SC lines that keeps me loyal. Also I have too much money already invested in her to giver her up.

So far I have upgraded as follws:

-SSIs
-Bursch Exhaust
-Turbo Tie Rods
-7 & 9" Fuchs with SO3s
-New floor mats


Overall the car drives "OK". The CIS started to run really poorly this year.

Without the benefit of a local expert on EFI conversions is there a good alternative to CIS? Is going to a PMO carb a bad idea?

From a suspension perspective, I seem to have a mix of too much body roll and very harsh ride over sharp bumps? Would a new set of Bilsteins improve my ride?

What about a set of sport seats? The driver side seat looks great but has lost its seat foam cushioning

Here are some pics...any other ideas?

[T-Bone911]

Lower, corner ballance, t-bars, sway bars and shocks will improve the handling largly. 993 brakes will make it stop. EFI, 964 cams, 3.2 p/c and have fun.

[GaryR]

I love the "clean" look of PMO's, can't comment on their effect on the car vs CIS but I bet they are easier to work on! How about welding in a full cage or at least those Targa body stiffeners to start, then maybe some adjustable sways, heavier torsion bars and custom valved Bilsteins! I use Performance Friction (97 compound) pads with stock calipers/rotors. work great!

[cubby911T]

ooooohh......I like the Targa roll bar painted body color (at least, that's what it looks like in the pic) - nice!!! The duck tail looks good on your SC too!!!

[coldstart]

Really nice SC. I think I saw your car on the road last month around Yonge and Yorkmills/401. Is the used market that bad in Toronto? I always thought Ontario cars were overpriced comparatively.

I would spend the money on getting your car working well. Carbs are not a bad option if the CIS is acting up or you could just have the CIS fixed. Mantis will gladly your newly found cash and have your car running well. Suspension upgrades usually do wonders too.

[cbeers]

If it's running well, then I would look at suspension mods. You mentioned Bilsteins, do you have stock shocks?

Nice to see another painted targa bar





-Chris

[Superman]

Suspension work. New bushings, for example. I'd like stiffer torsion bars, Bilstein Sports and a through-the-body sway bar up front.

Carrera tensioners
Popoff Valve
Triad final exhaust.

[mb911]

efi from bitz is worth the money and he at least is in the same country

[mb911]

Superman

I see your post says triad final exhaust does that mean they (he) is not making mufflers anymore? Just curious as to why. No disrespect intended just personal curiousity

[sammyg2]

FIX THE CIS and then increase the intake manifold pressure.

[rfuerst911sc]

I have a 83SC coupe and came into the same type of situation where I came into some "free" money. I had $6500.00 I set aside for upgrades and I had already done Fuchs wheels,Bilstein shocks on all 4 corners,SSI's, performance muffler. So here's what I got for $6500.00-Corbeau CR1 seats,laptop computer for EFI,front suspension bushings,Weber manifolds and linkage,Heet sheets,17 inch rims and tires and ITB EFI complete setup from Motomotions and I still have $900.00 left over to purchase front and rear torsion bars and the rear bushings. I purchased many items used to save money.Hope this helps.

[Superman]

The rear spring plate bushings are going to make a big improvement in handling.

Ben, Dave is still busy making final exhausts. I'd say that mufflers and a resonating chamber are components. To me, a 911 exhaust system has two parts. The part that bolts to the heads (headers, heat exchangers, whatever), and the "final exhaust." Dave is still very much in business. I just got my car back on the road, and I had forgotten how wonderful these engines sound. I still think Triad is the best I have ever heard, and it looks like your system would sound good too.

[SCOTITUDE]

First fix the CIS. Its pretty reliable. The PMO's IMHO wont give you much of a boost in hp for the 3g investment beside the clean look. Then new/revalved shocks, torsions, sways, stiff bushings, corner balance, lowered ride height, monoballs front and rear and a hot alignment. As far as brakes, I would add a turbo MC before you spend the $ on 993 brakes. This did wonders for me on the track. Gave me a great pedal, no more mush, no fade. I have been tracking the car for 9 years (DE) with stock calipers and Pagid oranges and they have worked beautifully. I have pushed 993 calipers down on the list since this setup worked so well. Good luck.

[Grady Clay]

This is for a nice street ’81 911SC that sees an occasional track day.

I would split the windfall between some serious long term maintenance, some increased performance and reliability upgrades, and some very little eye candy.

I would use the opportunity to go through the engine, trans and suspension.

The engine could greatly benefit from a proper refreshing with re-done heads, new P&Cs, new bearings and assorted parts (Turbo oil pump, late tensioners, cylinder head studs, valve springs, larger crank pulley, CIS pop-off, etc.) Install SSI at the same time (when the heads are off, have new exhaust studs installed.) There are a few things you can change to improve the performance without any decrease in reliability (cams, increased displacement, slightly higher compression, twin plugs, etc.)

Do a regular maintenance overhaul on the transmission. Replace all eight bearings, new syncros and sliding sleeves, etc. Install the later reinforced differential cover. Install LSD if you want. Depending on your use, slightly shorter gears are fun. The shifter upgrades would be very nice.

Your ’81 probably has the 100 mm CV joints; upgrade to new Turbo (928) 108 mm CV axles.

Install the late Carrera front oil cooler and electric fan.

Is it appropriate to improve the A/C? Barrier hoses and some upgrades can make a trip from Toronto to San Diego very pleasant.

Your 911 is pretty low for standard torsion bars. I’ll bet it is on the rubber bump stops some of the time. The 22/28 mm torsion bars, bearing suspension, adjustable sway bar, proper new shocks, ball joints & tie rod ends, and perhaps bigger brakes would make it much more fun on the street and track.

There are a myriad of little things to do. Lube the window mechanism, door locks and latches and the door restraint. Make sure the heater controls are perfect. Clean the oil sump tank. Lube all the linkage, replace bushings and free all the adjustments. And much more. A through underside cleaning while everything is apart is very satisfying.

Generally speaking Fuchs 7x16 with 205/55-16 and 8x16 with 225/50-16 are very pleasant for the street and look nice. Yes you can go larger if you are willing to mod fenders, put up with increased tracking of uneven pavement, poor wet performance and possibly reduced tire life. Anything is possible but everything is a compromise.

So, what do you have? Effectively you have the same car; except mechanically close to new (not 24 years old.) Improved handling, better performance, better reliability and lower long term stress, A/C that works when it is hot, and the satisfaction of knowing many of the critical areas of the car are new or better. Most of this has to be done sooner or later, doing it all at once has some significant efficiencies.

Ok what bling suits your fancy? Different seats; leather, blue/white/black hounds-tooth inlays, competition belts, modern sound system, etc.

Start with a well thought out plan and budget.
If you can’t find someone at home; drive somewhere in the States and fly home. Make a vacation out of it.

Best,
Grady

[Superman]

Drop a 3.6 Varioram in.

[Brian 162]

Consider getting the factory short shift kit. My 915 shifts very smoothly.(Even at Shannonville). I also installed adjustable sway bars, and replaced the struts.Carbs from what I hear greatly reduce gas mileage. I would fix the CIS system.

Brian

[twobone]

Thanks to everyone who has replied!

This gives me a great list of ideas to start looking at

[twobone]

Hi Grady,

further to your comments:

Your 911 is pretty low for standard torsion bars. I’ll bet it is on the rubber bump stops some of the time. The 22/28 mm torsion bars, bearing suspension, adjustable sway bar, proper new shocks, ball joints & tie rod ends, and perhaps bigger brakes would make it much more fun on the street and track.

What would be the stock torsion bars? Tell me what the change to 22/28mm would do for me?

[johnsjmc]

Rebuild the old suspension first . I would expect benefit from replacing as many rubber parts as possible. Rebuild your shocks if Bilstein or replace if another brand.Carrera swaybars(1986) are an inexpensive upgrade while in there.I would also expect your trans is also tired by now.I also like adding a better fender oil cooler for improved engine life

[Grady Clay]

The biggest issue is suspension travel – there is only so much available. As you lower a 911 that also reduces the available suspension travel. With stock (high) ride height and stock (soft) torsion bar springs, a Big Bump (BB) is taken up by the suspension deflection without hitting the rubber stops in the shocks.

When you lower a 911, with no other change, the BB still deflects the suspension by the same amount. The difference is there isn’t the available travel before you hit the rubber stops. Consequently, the suspension “bottoms” on the stops with a BB. This makes for poor handling particularly if the front or rear hits first.

There are several “cures” for this problem: Install stiffer torsion springs, remove some of the bump stop, modify the shocks and reposition the suspension upwards in the 911. Needless to say the first two or three choices are cost effective on a street 911.

The constraining factors are: You can only use a torsion spring so stiff; more uses the chassis as a spring and deteriorates handling. The bump stops in the shocks are necessary to protect the shock from damage if fully collapsed. You can order shocks with the shaft modified so it can’t bottom unless the suspension is hitting the chassis; expensive but effective. Only serious race 911s move the suspension points; not something for the street.

Above we have been talking about the mechanics of the suspension. Next you must consider dynamics; the handling. First you don’t want the suspension as stiff as a race car. It has to properly handle normal road conditions. That means it must be compliant enough to handle normal BBs. For those of us who remember freshman physics, this is a mass-spring-damper system. Automobile suspension systems only work in a small window of mass (un-sprung to sprung mass), torsion spring rates in N/cm (#/in) at the tire, the shock rates are over-damped but too much feels solid and makes for poor handling. All of these things must act in concert.

All of the suspension parameters are a compromise. You just want the compromise to make for proper handling and “feel” for your use.

I think the stock torsion springs for your 911 are 19/24. The spring rate increases with the 4th power of the diameter. I’m sure someone has worked out the spring rate at the tire for the various diameter torsion bars.

The torsion spring rate and the shock rate need to be changed in conjunction with each other. Stiff springs make for a “firm” ride. Stiff shocks make for a “harsh” ride. Increase the torsion spring rate more than the shock rate.

The change to stiffer torsion springs will result in the suspension not bottoming with the BB (not suddenly having much stiffer spring rate when on the stops) and reacting quicker to steering input – more responsive. The down side is it has a stiffer ride if comfort is an issue.

Everything is a compromise.

2˘ tour.

Best,
Grady