Roamer

I have recently purchased an 86 Carrera and would like to take a careful and well planned build-up of the car. My current plans include updating the torsion bars (22/29) and either adding boxter calipers or going with 930 brakes. The car already has the factory sport suspension, locking diff, the bushings are in very good condition and I am currently installing turbo tie rods, short-shift kit and gated shifter. I already have an SCCA competition license and I am also taking driver's ed classes to learn the proper way to drive a 911 fast so I won't be a yahoo with too much power.

I would like to see the car get into the mid to low 13's in the 1/4 for more fun on the street and quicker acceleration out of the corners on the track. To do this I will probably need in excess of 320 flywheel hp. The question is what is the most economical and reliable way to get there. My choices (I believe) are:

1. Enlarge to a 3.4 with 10-11 to 1 compression, dual plug heads, port and polish, mass air with fuel controller, possible ignition upgrades and cams;

2. Swap to a 3.6 minor upgrades;

3. Swap to a 3.3 turbo motor; or

4. Supercharge.

Does anyone have rough cost estimates and/or experience with any of the above that could proivde some guidance so I can begin my quest?

Thank you in advance for your advice!

Marc
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

t.p.

from what i've heard, option one will not get you to 320 hp. I'd do option 2 or 3 (tried and true). i would shy away from option 4.

Jim Michaels

I don't think a '90-'94 3.6 with minor upgrades will get you to 320 either. From what I've read and heard, the most economical and reliable way to get to 320 is to buy a used 911 turbo (the whole car, not just the motor). You could try to stuff a turbo motor in the car you have, but then you'll want the big wheels and tires, better brakes, upgraded suspension, etc. The conversion would be expensive, and you still wouldn't have a proper chassis for all that power. Sorry, I know that isn't what you wanted to hear.

Roamer

Jim and T.P., thanks for the initial input. Jim, you are right I don't want to hear that I should purchase another car. I have a hard time believing that it would cost me over 12k to make the upgrades that I have listed add modify/add the engine. I also like the narrow body and targa over the wide-bodied turbos (lighter). However, I do appreciate the input.

T.P., what amount could I expect out of an engine rebuild as listed, and how much $? Also, do I really need 320+ to get into the 13's, or could I go with 280-300 which should be feasible with a modified 3.4 or 3.6?

t.p.

about 260 h.p.? not too sure. too much $$ to do though. buy a 993 3.6, which is around 280 stock h.p., and go from there. you should be able to get into the mid 13's, with some minor mods and weight reduction. a turbo is good too because simple mods (I/C, bigger turbo, boost spring) yield big results - 350+ hp. A used 930 engine can be had for $5-7k. That means that for around 10-12k (after you're done), you can have a killer engine.

Gus B.

Contact Steve Weinner at Rennsport and ask him about doing some tranny gear ratio changes. Looks like you are mostly into 1/4 mi. racing, so he can easily set you up with the proper gear ratios. Maybe you do not need as much hp as you believe! Also, make the car lighter by removing whatever you can afford living without.

Good luck <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />

Steve Weiner-Rennsport Systems

Hi Marc:

I hope you don't mind some input here as this what I do for a living,......

First, 1/4 mile times and speeds are as much about driver skills and how badly one is willing to abuse their car as about power.

Now, lets look at your proposals:

1) There is no simple way you can make a good 3.4, 250+ HP engine for under $ 12K. The parts and labor will exceed that if everything is done correctly. A 270-300+ HP 3.4 will not be real streetable and will not pass smog tests.

2) A good Varioram 3.6 with RS cams and a good chip will make 300+ HP if this all done right. This amount of torque, coupled with a good close-ratio gearbox, makes an awesome combination and would be the ticket here and my recommendation. This will cost in excess of $ 15K for everything. Don't forget, this combo needs dual front oil coolers.

3) A 3.3 Turbo motor conversion can certainly make over 300 HP with ease, the issue is drivability. Most people really want acceleration; they want a real quick 0-100 car and the above (#2) combo is lots faster than this option up to 100 MPH. This can only be done under your budget IF,..if the donor Turbo engine is quite healthy.

4) Just my opinion, but I do not recommend aftermarket supercharger or Turbo kits. They certainly make great power, but with a toll on long term engine longevity. The factory turbo engines have metallurgical & design differences from their naturally-aspirated counterparts that allows them to handle the incredible top-end heat that they must endure. Watching the heat exchangers, turbocharger & muffler system glow red at only .8 bar of boost on the engine dyno here, will impress anyone how really hot these do run. You really cannot see that under the car,...

(higher boost levels produce bright red -to-yellow metal parts)

Remember, a good close-ratio transmission is an integral part of eny performance upgrade and I'd strongly recommend this before any engine modications or changes are done.

Other stuff:
Your ideas about torsion bar upgrades is excellent and I'd further suggest Bilstein sport rear shocks and HD's on the front. Finishing that off with a set of larger adjustable swaybars will give you an excellent handling street/track car. As mentioned below, larger rear torsion bars should be used for a 930 or 3.6 conversion.

Lastly, do not compare the Boxster brake upgrade with Turbo ones,...Its a night and day difference and if you use your car for DE evets, the Turbo brakes are the only way to go (retaining your 16" wheels, anyway).

It sounds like you are going to have lots of fun with your car,...

I hope this helped a little and will have saved you money as start your project.

Dean

I installed a 75 930 motor in my 81 SC. The motor cost me 5k. It had some issues. The total cost to put the just the motor in my car was @ $8k. I did all the work. I think it is hard to find a good 930 motor for under $7k. I completely enjoy my car now. Of course it could always be a little faster ;-)

Bill Gregory

A 964 3.6L engine will get you 250 hp and a 993 3.6L engine 280 hp, both in stock form. I believe both weigh more than the 3.2L engine, so if you go that route, you may want to consider 30mm rear torsion bars. In my SC I had 22/29's with Bilstein Sports on both ends, which was a nice combination on street and track.

The Carrera brakes are pretty good, but if you need more heat sink capacity, the Turbo brakes certainly do that. There's an article on tech.rennlist.com on upgrading to 930 brakes, which may be of interest. Pictures in the performance section of the 911SC FAQ, also on that site (or the first page of these forums).

A Quiet Boom

I'd go with options 2 or 3 as well, option one is about 1.5 hp/cubic inch which is way up in the lumpy cam, hard to drive, high compression racecar territory. The turbo on the other hand will give you close to 300 right out of the box depending on the year engine you get. A few upgrades and you've achieved your goal. However there is a lot more involved than just bolting the motor in, you'll need a turbo tail for the intercooler for starters.

Targamike

Bill-
I had actually thought that the 3.6 was lighter than the 3.2 (and the 3.0). This was from Steve Timmins (the guy who sells the conversion kit). Anyone know for sure about this????
Mike

Martin S.

Marc,

1st, read Steve Weiner's post above. He is a Guru to this and other Boards on Rennlist. He is out of a "real" shop, Rennsport in Portland, OR. His advice is invaluable. People have been known to crate up motors from all across the US and send them to Steve for a re-work.

2nd, you mentioned that you want to "see the car get into the mid to low 13's in the 1/4 for more fun on the street and quicker acceleration out of the corners on the track." Unless you have a very fat wallet, it ain't going to happen. And if you do have a fat wallet, and you get 300 + HP out of a Carrera engine, it will not be a car you will want to drive on the street. In order to tame the HP, the suspension will be set up very stiff..it will probably knock your fillings out, assuming you have fillings.

Furthermore, even with all the 300+ HP mods, chances are street racers with Rice Rockets will "clean your clock" with due regularity...check out some of the 1/4 mile times some of the Honda Civics, etc. are posting. AS was once written, "Don't race Mustangs or Camero cars." Add rice rockets to the list. In addition, in case you are not aware, a 915 transmission in the 86 Carrera does not adapt well to drag racing. It expresses it's distaste for this activity by self destructing. It can only be made better with a transfusion of about $4,000, or more, depending on what you break. 1st gear in a Porsche car is a "get going" gear...and not a gear that can take too many clutch dumps as in drag racing.

The following mods you suggested are very well thought out: Shifter gate, (22/29) torsion bars, and 930 brakes. No problem running 930 brakes, excellent selection.When you go to Boxster brakes, I believe you will need to go to 17" wheels, an added expense.

Also good selection in having the Turbo Tie rod ends installed. Since lowering a 86 Carrera is simply a torsion bar adjustment (well, not quite that simple), lower the car, align it, and add a bump steer kit for the front steering rack.

Get a second set of wheels and equip them with R tires with a tread rating under 100. You already have some decent sized sway bars that Porsche added the 86 model cars. Put a racing seat in the car and 5 point belts, a roll bar is a good idea as well...head out to the track, Watkins Glen, Lime Rock...check your local PCA for Driver Education events. Drive the car and then make the decision as to whether or not you need all the mods you are contemplating. You will be pleasantly surprised at the limits of a bone stock (motor wise) 86 Carrera.

Once you have mastered the car and you start winning your class, then it may time to do the extra HP mods. If you don't know how to drive a moderate Porsche car of 200 HP or so, adding another 100 HP to the equation will compound the problem...you'll spend a lot of time going backward...not a pleasant past time.

I went from a 175 HP 911SC to a 97 Carrera with over 100 more HP, and not that much heavier a car. First few times on the track were spooky.

Pelican Auto Parts has an article I wrote a while back on preparing a 911 for the track. If you can't find it, I'll send it to you.

Good luck with the 86 Carrera...treat it right and it will treat you right, they are great cars. By the way, Chicago PCA is having a Labor Day Club Race and Driver Education event...check it out, just a skip and a jump over from W. New York. With youe SCCA background and recent DE events, you may have enough experience to enter. Three (3) 5th gear straights and a 4 mile track...too much fun!!!

Ed Bighi

First things first. If you are going to quarter mile that car, don't waste too much time messing with anything else other than the motor. If you really want to waste your time in that endevour, use a crappy car. If by your mentioning quarter mile, you are referring to measure of outright performance of the car instead of actually using the car for drag racing on a regular basis, then ok. But, quarter mile performance will not be an accurate measure of the car's track ability. And on that point, 300+ hp is really not necessary to go quite fast on a track. Unless you cannot drive a 911 well. And if you start out with that hp, you will eventually become a hp ***** like a lot of people I know who never learned the fine art of milking every half hp out of a 911. I use a lightened sc with stock motor and have not had any problem passing anything with less than 380hp on a track. Ever. Unless it is another 911 with an excellent driver. I call it the 911 factor. They seem to do what other cars need 100hp more to do. Now as far as suspension, I do believe in going stiffer since they come a little softly sprung. Bigger torsion bars make a more reactive car that even though will snap sideways much quicker, will get back on line much quicker also. I run 23/30 on mine. I used no science in choosing those sizes. I selected that size since they are the biggest ones in a solid configuration. In tubular you can go to 23.5 with effective rate of 23 and a 32 rear with effective rate of 31. But getting back to the hp thing, you don't really need it. I'm telling you this because you have an scca license which means you should be up to speed on 10/10ths driving. I am also a believer in the balanced car idea. Not front to rear balance but a balance of the overall performance capability of different items on the car. In my car, I took all the luxury items out of the car like power windows, ac, heat, carpeting, rear seats, etc... bringing the weight down to the mid 2,200's. What I ended up with is every component of the car being maximized on an equal basis instead of the trial and error of needing a little bigger this and that to equal things out. It has worked like a charm. That is why I haven't messed with the hp. The car is in a happy medium. A few years ago, I though about going with a turbo motor but decided against it since I did not want to change every component in the car to go along with it. Everyone who has ever seen or ridden in my car has changed their mind on what is truly required to go fast. About five years ago, I thought I needed 100hp more. About 3 years ago, I changed my mind and thought I needed 50hp more. By now, with still the same hp as five years ago, I feel I only need a new set of brake pads and a brake fluid change for the upcoming season. I laugh now when I look back to that point five years back when I thought I knew my car. Little did I know about its capabilities. But if today I wanted big hp, my choice would be a 3.3 turbo as a starting point since I spent enough time driving them on the track to really enjoy the extra mental challenge they present. To me it is the conversion that makes the most sense on a dollar per hp perspective because of the ease of making big hp in those while still passing emissions.

k9handler

My .02 worth...
Keep the car a healthy stock Carerra and have fun at your local PCA/SCCA DE and Autocross events!!!
This car will bring you much more joy going around a road course than down a damn quarter mile.

But that's just me.

A Quiet Boom

A lot of guys here are down on the idea of quarter miling your car and it's understandable, I'm an avid 1/4 mile racer with a completely set up naturally aspirated drag car, I only recently got into P-cars and at first all I could think about was getting my car to go faster at straight line acceleration. The truth is the 911 is the WRONG car for that endeavor. Low 13's in the quarter? give me a total beater 5.0 mustang and about $1000 I'll do it all day long without barely a mod to the motor. But take that same Mustang and try to make it faster around a road course than a 911 and I bet I spend in excess of $10,000 trying to do it. Now if your want to make your P-car throw you back into the seat when you step on the loud pedal that's fine, forget about HP, build all the torque you can, I can almost guarrantee a properly setup 3.6 will be the most fun in your car compared to anything else on your list, why? well large displacement by nature brings more torque especially down low where it's most noticeable, a good exhaust, intake, cam timing and matching gearset will make this even more fun. Faster out of the corners? there's nothing like the instant torque of a large displacement motor compared to the same torque from a turbo or centrifugally supercharged motor that comes on soft due to lag. I'm not trying to discourage you here, but the 911's strengths on a roadcourse are it's downfall at the dragstrip, stiff suspension, front sway bars, independent rearends, slow-shifting trannies, etc. are all detrimental to 1/4 mile performance. That said, I'm not saying it can't be done or even shouldn't be done, in fact I personally believe our cars should be capable of at least high 13's in stock form right from the factory. Sure 911's may not need all that power but for the money spent they should be quicker IMHO. A turbo will definately make it a lot faster and you could probably even get into the 12's with it but it won't necessarily more fun than a 3.6 on the street.

Sorry just some needless rambling from a certified speed junkie <img src="graemlins/yltype.gif" border="0" alt="[typing]" />