How big can a 3.2 engine safely get?

[uwanna]

Originally Posted by Jgordon

And it's more unique. If you hit 280 or 290 on a one of a kind built up 3.4 or 3.5, I'd think the cool factor makes up for the missing 10 hp. Unless you're that serious at the track, in which case buy the 3.6 and have someone build THAT up.

Yea, back in the early '70s(yes I am an old fart), I felt like you about the cool factor,
and built up a couple of 2.0s into 2.5 hot rod motors, with Vertex magneto ignition, 10.5/1 C/R
big Webers, cams, etc,etc. Had a lot of fun, and my share of headaches. That said, my 3.6 has been flawlessly trouble free low these 22yrs since '92 and is just a weekend ride. No more track/autocross for me! I think it comes with age, LOL.

[Trackrash]

Maybe rlane will chime in. 3.2 mfi

[Allan Kelsey]

I do love the idea of reliability & I will not be unhappy if I don't get exactly 300hp.
285 will work & so would 315.
But I'm hoping for more than 250 and I don't think I need 350..
I have enough of a lead foot already. (Blaming my motor racing father for that genetic defect)

Yes, the unknown of buying a used 3.6 does creep over the line from risk to gambling.....

[mreid]

Allan, I have two 3.6 engines that have both required some work. The biggest expense however, came with the required parts to make them work in an earlier chassis with a 915. Right now, I am building a 3.0 twin plug, 10.5 to 1, PMO carb engine that will go in my 904. All in, that car will weight less than 2000 lbs. with a full tank of gas and my ample self. The engine will end up in the 250 to 270 HP range (this via Bob Jones at Jones Autowerks).

For you, cams, twin plug heads, a proper exhaust, and intake replacement or tuning along with a weight reduction regime for your car will yield big results at a significantly lower price tag than a 3.6 conversion. All depending on how much you do yourself.

[wildthing]

If more power is your objective, sell me that car and go buy a 993.

[Bill Verburg]

It looks like you want a mostly street car, if so torque, tractability and reliability are what you really want, in other words a street motor.

Sure you can get 300 +/- hp from a built 3.2-3.4 but to do so you need cams and intake and exhaust and p/c and rods and oiling etc. that all work at higher rpm than you can now use, the engine will be way less tractable, ie the torque comes in higher in the rev range, the idle will be less stable all in all the car will be less derivable on the street at lower revs.

What you want is torque at a usefully low rev range

3 ways to get it, turbo(out because you want n/a), gearing(this is possible) displacement(3.6 -4.0)

You can build the 3.2 to 3.4 reliably but to use much happier cams you need pistons w/ valve reliefs and engine management that is less sensitive to intake manifold vacuum fluctuation than Motronic, if you raise the revs enough you will also need to address the crank, rods and oiing, to raise the cr you will want twin ignition. It goes on and on and is expensive.

Buy a 3.6( rebuild it if necessary) a stock 3.6 has 228-250 ft-lbs of torque at the flywheel stock(964 at the low end 993vram at the top) build a 3.8 at it gets better.

The engines come stock in a very reliable, hi c/r package, very tractable and mesh well w/ earlier chassis and transmissions you won't be sorry w/ the right engine installed correctly.

just for comparison;
'74 3.0 RSR 231lb-ft@6500
stock US 3.2 192-195 ft-lbs@4000
SC/RS 3.0 188 ft-lb@6500
964 3.6 228lb-ft@4800
964RS 3.6 239lb-ft@4800
993nvram 3.6 242lb-ft@5000
993vram 3.6 250lb-ft@5250
993RS 3.8 261lb-ft@5400
993Cup 3.8 279lb-ft@5500
993RSR 3.8 279lb-ft@5500

[fred cook]

Originally Posted by mreid

Allan, I have two 3.6 engines that have both required some work. The biggest expense however, came with the required parts to make them work in an earlier chassis with a 915. Right now, I am building a 3.0 twin plug, 10.5 to 1, PMO carb engine that will go in my 904. All in, that car will weight less than 2000 lbs. with a full tank of gas and my ample self. The engine will end up in the 250 to 270 HP range (this via Bob Jones at Jones Autowerks).

For you, cams, twin plug heads, a proper exhaust, and intake replacement or tuning along with a weight reduction regime for your car will yield big results at a significantly lower price tag than a 3.6 conversion. All depending on how much you do yourself.

+1 on this route. I pulled about 300 lbs off my 1980 SC Coupe and rebuilt the engine into a 3.3SS. Carrera heads, 100mm Mahle 10.1:1 pistons, LN Engineering cylinders, 964 cams, Electromotive XDi twin plug ignition and an early large port CIS system. Exhaust is by SSIs and a 2 in/1 out muffler. Haven't had a chance to put it on a dyno yet, but "seat of the pants" power seems to be quite good and the reduced weight makes for a better handling chassis. Cost to build this engine was around $12k with all the labor provided by myself. The only thing I farmed out was to have a valve job done on the heads by Xtreme Cylinder Heads in Florida. This engine is very comfortable on premium (91 octane) pump gas as it only requires 24-25 degrees advance with the twin plug ignition. It might even run ok on 89 octane but I haven't tried that yet. The ignition cutout is set at 7500 rpms. I haven't bumped up against the cutout yet, but I have buzzed it up to 7K a time or two where it was still pulling strong.

[porsche0nut]

Originally Posted by fred cook

+1 on this route. I pulled about 300 lbs off my 1980 SC Coupe and rebuilt the engine into a 3.3SS. Carrera heads, 100mm Mahle 10.1:1 pistons, LN Engineering cylinders, 964 cams, Electromotive XDi twin plug ignition and an early large port CIS system. Exhaust is by SSIs and a 2 in/1 out muffler. Haven't had a chance to put it on a dyno yet, but "seat of the pants" power seems to be quite good and the reduced weight makes for a better handling chassis. Cost to build this engine was around $12k with all the labor provided by myself. The only thing I farmed out was to have a valve job done on the heads by Xtreme Cylinder Heads in Florida. This engine is very comfortable on premium (91 octane) pump gas as it only requires 24-25 degrees advance with the twin plug ignition. It might even run ok on 89 octane but I haven't tried that yet. The ignition cutout is set at 7500 rpms. I haven't bumped up against the cutout yet, but I have buzzed it up to 7K a time or two where it was still pulling strong.

Change out those SSI's for headers with 1-5/8" primaries and you'll see an even bigger improvement - SSI's are fairly restrictive for a 3.3L engine (better suited for <3.0L), especially with 964 cams. Add a wong chip and you're set!

[fred cook]

Originally Posted by porsche0nut

Change out those SSI's for headers with 1-5/8" primaries and you'll see an even bigger improvement - SSI's are fairly restrictive for a 3.3L engine (better suited for <3.0L), especially with 964 cams. Add a wong chip and you're set!

I thought about the headers, but I needed to keep the heat functional. The SCs don't use a "chip" all of that came along in 1984! If I can find a set of appropriately sized headers w/heat I might go that route. Also, at some point I will most likely replace the CIS with a set of 46mm PMOs, but for now I want to keep the fuel efficiency of the injection. After I get it on the dyno I will make decisions about more work on this engine.

[uwanna]

Originally Posted by Bill Verburg

It looks like you want a mostly street car, if so torque, tractability and reliability are what you really want, in other words a street motor.

Sure you can get 300 +/- hp from a built 3.2-3.4 but to do so you need cams and intake and exhaust and p/c and rods and oiling etc. that all work at higher rpm than you can now use, the engine will be way less tractable, ie the torque comes in higher in the rev range, the idle will be less stable all in all the car will be less derivable on the street at lower revs.

What you want is torque at a usefully low rev range

3 ways to get it, turbo(out because you want n/a), gearing(this is possible) displacement(3.6 -4.0)

You can build the 3.2 to 3.4 reliably but to use much happier cams you need pistons w/ valve reliefs and engine management that is less sensitive to intake manifold vacuum fluctuation than Motronic, if you raise the revs enough you will also need to address the crank, rods and oiing, to raise the cr you will want twin ignition. It goes on and on and is expensive.

Buy a 3.6( rebuild it if necessary) a stock 3.6 has 228-250 ft-lbs of torque at the flywheel stock(964 at the low end 993vram at the top) build a 3.8 at it gets better.

The engines come stock in a very reliable, hi c/r package, very tractable and mesh well w/ earlier chassis and transmissions you won't be sorry w/ the right engine installed correctly.

just for comparison;
'74 3.0 RSR 231lb-ft@6500
stock US 3.2 192-195 ft-lbs@4000
SC/RS 3.0 188 ft-lb@6500
964 3.6 228lb-ft@4800
964RS 3.6 239lb-ft@4800
993nvram 3.6 242lb-ft@5000
993vram 3.6 250lb-ft@5250
993RS 3.8 261lb-ft@5400
993Cup 3.8 279lb-ft@5500
993RSR 3.8 279lb-ft@5500

Bill,
I think you hit the nail right on the head! I was thinking most of the things you said,
but could not express it as well as you. After 22yrs with a 3.6 addition to my '80SC,
I am still pleased with it every time I turn the key! Great street car, and trouble free.
Only addition I covet would be a G50, but that's too much surgery and dollars.
Grant

[Allan Kelsey]

So, a recent investigation of gently used 993 engines shows asking prices around 10K.
Assuming I can find one with an accurate representation and genuinely doesnt need any additional love, other than an oil change - what is the additional cost to mate it to a 915 tranny and install?

[NY65912]

Allan, building a big engine is big fun and costs big money as well. My 3.7+ engine cost more than 40K with tuning. It's not for the faint of heart or pocket book. I say a 3.6 is the way to go, but your still looking at over 15K.

My New Track Engine Debut

Good Luck, and beware the "Slippery Slope".

[Tippy]

Allan, building a big engine is big fun and costs big money as well. My 3.7+ engine cost more than 40K with tuning. It's not for the faint of heart or pocket book. I say a 3.6 is the way to go, but your still looking at over 15K.



My New Track Engine Debut



Good Luck, and beware the "Slippery Slope".

I would love to flat top piston your engine and throw a monster turbo or twins on it.

Did it make 400hp? Couldn't find.

[Bill Verburg]

Originally Posted by Allan Kelsey

So, a recent investigation of gently used 993 engines shows asking prices around 10K.
Assuming I can find one with an accurate representation and genuinely doesnt need any additional love, other than an oil change - what is the additional cost to mate it to a 915 tranny and install?

Instant-G
has a cost estimator

easiest and cheapest as any of the OBD1 3.6 engines, these come from any n/a 964, '95 US 993, any n/a RoW 993, more complicated and expensive is the US '96 -98 993.

to further complicate the issue any of the OBD 1 DME's have used replaceable push in chips, '96 US 993 DME was a one year design 2 chip design that can't be reflashed, '97-98 DME has a soldered in chip set that needs to be removed and re-installed to reflash, this is not something most owners will wish to attempt.

so best advice look for a 964, US 95 993 or RoW 993, the best fit is the US '95 non vram 993, both of the others fit but the tall intake on the 964 causes issues as does the bigger vram manifold both work

The one I like the best in this chassis is the US '95 993

my '76 C3 w/ 964


my '76 C3 w/ 3.8RS


my '76 C3 w/ '95 US 3.6

[uwanna]

Originally Posted by Allan Kelsey

So, a recent investigation of gently used 993 engines shows asking prices around 10K.
Assuming I can find one with an accurate representation and genuinely doesnt need any additional love, other than an oil change - what is the additional cost to mate it to a 915 tranny and install?

Here's the pieces/part to "git er dun". just one of couple of folks who offer this.
You don't need to buy all the stuff, if you're mechanically inclined, and can read a wiring diagram, you can fabricate some of the stuff on your own. The pricey engine tin package can be easily done by you. One caution, if you want to keep AC, '96 motor Vram intake assy will not allow room for an AC condenser. I would look for a good 964, or a 993 earlier than '96.
If you do a google search on this forum, you will find tons of info on this swap that have been done by some very resourceful Pelicans.

993 (3.6L DME) Engine Conversion to Porsche 911 / 915 By Patrick Motorsports Porsche & Mid Engine Performance Specialists

[mreid]

The 95 993 3.6 is the way to go. The 964 has an externally balanced crank and solid lifters that require adjustment.

[Allan Kelsey]

Originally Posted by NY65912

Allan, building a big engine is big fun and costs big money as well. My 3.7+ engine cost more than 40K with tuning. It's not for the faint of heart or pocket book. I say a 3.6 is the way to go, but your still looking at over 15K.

My New Track Engine Debut

Good Luck, and beware the "Slippery Slope".

Mike,
I watched your build with great enthusiasm and am SO grateful that you were willing to share your build journey, it was an great learning opportunity for me to watch!

Thank you.

[r-mm]

Wondering how you came up with the 300hp target. Are you feeling like your car needs a transformational kick in the pants to be exciting? Or do you want to keep it somewhat original but still have a lot more than you did before?

Can't help but be impressed with a lot of the dyno charts on Steve Wong's website. Pick your recipe... but I'm seeing a lot of ways to spend $10,000 (price of 3.6 you quoted) and end up with one hell of an enjoyable, revvy, original, rebuilt 3.2. Slight overbore, high comp, twin plug if you need it, 93 octane chip, exhaust, arp headstuds for some more revs, street cams that keep power down low...

I might be in the minority but my feeling is that as long as a car is not embarrassingly slow, I'd rather be able to wring its neck every day in every gear than to have too much motor or to stretch my budget and not be able to pay as much attention to longevity as I do bling in my build.

Of course there is no way on earth you'd be unhappy with a 3.6, I'm just thinking there are plenty of tried and true ways to hop up the motor your car came with.


A few snippets from 911chips.com

Here is Jeremy Dixon's '87 Carrera which was rebuilt from 3.2 liters to 3.4 liters with a Malhe 3.4l 9.8:1 piston and cylinder conversion set. The engine is modifed with the following: 1 3/4" B&B headers, ExtrudeHoned intake manifolds, FFenSport bored throttle body, 993SS cams, ARP rod bolts, Competition springs and retainers, and a Magnaflow muffler. Along with our custom chip for a 3.4 conversion programmed for 93 octane fuel, the engine produces a peak of 244 hp at the rear wheels.Factoring a 15% drivetrain loss, the engine produces 288 hp at the crank.

The following run is from an '87 3.2 Carrera built by Autometrics Motorsports in Charleston, South Carolina on a Dynojet 248c. The engine modifications include the following: 10.3:1 cr pistons/cylinders, 964 cams, and headers with racing mufflers. The chip is a custom 911Chips program for the engine combination and 93 octane fuel. The engine produces a peak of 234 rwhp with our performance chip. At 6200 rpm, factoring a 15% drivetrain loss, this engine produces 275 crank hp.

The following runs are from an '84 3.2 Carrera on a Dynojet 248c. The engine is modified with the following: Euro compression pistons, racing headers, megaphones, ARP rodbolts, 9K valve springs, a racing valve job with polished ports, and Webcam 20/21 cams. The chip is a custom 911Chips program for the engine combination and 93 octane fuel. The engine produces a peak of 238.8 rwhp with our performance chip. At 6200 rpm, factoring a 15% drivetrain loss, this engine produces 281 crank hp.

[Allan Kelsey]

r-mm
Those are some very encouraging numbers and feel very attainable!
I dont intend to race the car, maybe a track day or 2 each year.
Otherwise, Im just a spirited driver with an enthusiasm for engine modification and a goal to improve the horsepower to get closer to 300hp at the crank. I chose that number because I have driven other - similar weighted vehicles - which ran a little under 300hp and it felt like a wonderful balance between power & weight.

Finally, for me, the payoff is also in the sound of a modified flat six in the upper rev range..... so delicious!

[ozracer]

That jeremy dixon engine build looks spot on Im in the same boat as you allan engine choice wise and I reckon that looks like the best all round compromise. No aftermarket ecu required either no twin plugging cos our fuel on this side of the world is good high octane as well.