Lets Talk HP numbers / Engines

[GotaT]

Ok... So, Ive got a very nice 71 targa w/ recent rebuilt 2.4 and a little hotter cams.. the car is a Blast to drive! but... as always.. Everyone wants MORE HP.. OH, Its mated to a 915 box.. which is also breaking in Nicely!

So Ive decided that If I were to rebuild another engine I would like to have in the upper 200 HP area... I figure that would be "Enough"

So, What are Good possibilites to start w/ and type of engine work needed to get this as a Daily driver?

[Steve@Rennsport]

Whats your budget?

[1972_911T]

Depends what you want from the car are you happy to have a modern looking engine in the back if so I would agree with noah 3.6 conversion would be easiest route into upper 200hp numbers. If money is not an issue and you want a somewhat stock ish looking motor then I would go with a 3.2SS. This engine is based on a 3.0 case and crank but using 98mm P&C's with some hot cams high CR twin plug and 46mm PMO's you would be seeing the high 200hp numbers. Cost wise ???? not cheap

Steve

[GotaT]

Ok.. Lets talk about the 3.6 for a minute.. doesnt this swap require Lots of mods compared to the 3.2 ? Whats the stock 3.6 produce?

[1972_911T]

A 964 produces around 250ish? while a 993 I belive has 265 I think alot of the differance came from the exhust so by running the 993 he's on a 964 you would get similar numbers. As for the conversion theres not alot of differance between the two as far as wiring goes the extra work is in the flywheel and clutch to get it to work with a 915. Patrick motorsport sell most of the conversion stuff I belive. Then theres a few other bits on the 3.6 to mod such as blanking off the powered steering pump. Do a search theres many threads on this. A 3.2 swap is simpler but it isnt going to get you the higher 200 numbers without extra work a stk ROW 3.2 was only 235?? Also you mag 915 wont stand up well to these sort of hp numbers with its 7:31 ring and pinion.

Steve

[Eagledriver]

Stock SC motor with carbs and exhaust will yield 220-240 and bolt right into your car. Minor changes for carbs and ignition are all you would need. A 3.0 with euro pistons and 39mm ports can put out 245 with 46mm carbs and good exhaust.

-Andy

[1972_911T]

Originally Posted by Eagledriver

Stock SC motor with carbs and exhaust will yield 220-240 and bolt right into your car. Minor changes for carbs and ignition are all you would need. A 3.0 with euro pistons and 39mm ports can put out 245 with 46mm carbs and good exhaust.

-Andy

What Andy suggests above has the obvious advantage of being far simpler to fit to an early car than the later 3.6 engines and wouldnt be too far from your goal HP in your early car this would still be lots of fun. This is prettmuch the route im going for my 72, 3.0 with 9.8:1 cr pistons, dc 20 cams mine will be twin plugged however and run on MS EFI.

Steve

[GotaT]

B/n the 3.2 and 3.6 which one is more Cost effective? I've looked into a 3.2 before and found one for 5500 w/ the DME and complete Engine. I found that to be very affordable .. now keep in mind it is Fuel injected... so W/ this type of setup what kind of HP ?

[Patrice911]

Here a chassis dyno run of my car. HP at the rear wheel. It's an 88 3.2 with DME, still the STOCK chip in it. The only mod done to it are a set of Bursch headers with a custom muffler with dual outlet. On the intake side there is a K&N cone filter mounted directly to to the air flow meter. Everything else so far I know is stock. A custom chip can probably bring the HP up as it is running fairly rich at higher RPM.
If a chip can bring about 10hp that will put it close to 240hp at the crank.

[GotaT]

Pat, I bet your car pulls pretty strong , ehh?

Lets turn the page a bit... What can be done to a 76 2.7 carrera engine? I belive this engine is stock w/ 180HP .....

[JeremyD]

Or take a 3.2 core and enlarge to 3.4 with 993 ss cams - still motronic (so keeps it driveability) the 993ss cams act like an early s car (power at the top end - comes on in a rush) flat torque curve - You don't have quite as much low end torque of the 3.6 (which should put less strain on your 915)

[spuggy]

It's often cheaper to drop in a stock 930 motor than lots of custom motor work.

They're fairly simple to wire in, and the 930 mates straight up to a 915. There's a Sachs competition pressure plate rated @ 350 ft/lbs which will deal with it just fine. (The Power Clutch is borderline, at best).

A stock US 3.3 930 (265 HP) or a RoW one (300 HP) both make enough torque to turn a mag-case 915 into soap. But a later 915 will live if you beef it intelligently and don't just mash the loud pedal at really low RPMs...

The big advantage of the 930 approach is when you dial in the suspension, brakes, tranny etc. get bored with 300HP and decide you want to add another 50, 100, 150HP - that particular route is relatively cheap, easy and well-travelled - to say nothing of being mostly bolt-ons...

Paradoxically, most 400-500HP 930's are easier to drive than the stock 930. With good headers and turbos, you lose the turbo lag and the sledgehammer-to-the-chest effect and end up with a tractable car instead...

[joetiii]

Originally Posted by Eagledriver

Stock SC motor with carbs and exhaust will yield 220-240 and bolt right into your car. Minor changes for carbs and ignition are all you would need. A 3.0 with euro pistons and 39mm ports can put out 245 with 46mm carbs and good exhaust.

-Andy

I've got 9.3:1 95mm pistons, PMO 40s, SSI, M&K for a total ouput of 204 HP and 214 lbs. trq. at the flywheel.

I am considering a shortstroke rebuild and want to limit my power to 240 ft lbs or so because I actually like the 901 shift pattern. Keeping the rear wheels planted on a light weight narrow body with power closer to 300 HP will be your next challenge.

I agree with the others that a turbo or 3.6 is the least expensive way for a big power upgrade but the trans will need to be upgraded too.

[spuggy]

Originally Posted by joetiii

Keeping the rear wheels planted on a light weight narrow body with power closer to 300 HP will be your next challenge.

Of all the money I spent, my vote for best "bang-for-the-buck" goes to the asymmetric lockup diff.

I already had 21/30 TBs, but the LSD makes a very useful difference under power, decelerating and through corners. Pretty much everywhere except cruising, really

[Eagledriver]

[QUOTE=joetiii;3668614]I've got 9.3:1 95mm pistons, PMO 40s, SSI, M&K for a total ouput of 204 HP and 214 lbs. trq. at the flywheel.

The small ports are probably hurting you the most. I also have an M&K muffler and I suspect it is costing some power as well. You have really good torque. You may also be able to run more ignition advance. I'm running 30 degrees total but some of our guys are running more. I don't know what the safe limit is. Our spec class has found that the big port motors have more power even with the stock 8.5 pistons than the small port motors.

-Andy

[safe]

Originally Posted by joetiii

I've got 9.3:1 95mm pistons, PMO 40s, SSI, M&K for a total ouput of 204 HP and 214 lbs. trq. at the flywheel.

With those pistons you are up to euro compression and should have 204 hp with the stock exhaust and CIS.

[1972_911T]

Originally Posted by safe

With those pistons you are up to euro compression and should have 204 hp with the stock exhaust and CIS.

Euro or rather ROW CR is 9.8:1, his engine will also be suffering from the small ports on the late US SC engines.

Steve

[safe]

Originally Posted by 1972_911T

Euro or rather ROW CR is 9.8:1, his engine will also be suffering from the small ports on the late US SC engines.

Steve

Your right about the compression, but the ports are equally small on the euro.

[joetiii]

GotaT,

Sorry if this thread is heading in a "how to get to 250 HP" direction. We can start a new thread. Spuggy is correct in that you will want to add some type of limited slip differential in a 8.3:1 915.

Originally Posted by Eagledriver

The small ports are probably hurting you the most. I also have an M&K muffler and I suspect it is costing some power as well. You have really good torque. You may also be able to run more ignition advance. I'm running 30 degrees total but some of our guys are running more. I don't know what the safe limit is. Our spec class has found that the big port motors have more power even with the stock 8.5 pistons than the small port motors.

-Andy

Andy, when the car was on the dyno, we advanced the timing to get these results, though I do not know what the final timing number is. I recocnize the later SC engine is more of a torque motor w/o the big port heads. I first considered hogging out the smaller intake and adding 964 cams but then I would be in the same boat as GotaT... I would be searching for more power a short time later.

GotaT - bumping power by over 35% in a 2400 lb car will make a huge differrence. I was thinking my measely 50 hp increase (25%) would be significant.

[1972_911T]

Originally Posted by safe

Your right about the compression, but the ports are equally small on the euro.

I Know in the rebuild book it states that the ROW post 79 SC's had small ports but in reality I dont think they did. I have stripped both a 83 and an 81 SC engine last year as well as my current 79 SC engine all three were ROW and all three had the large 39mm ports. These were not engines that had been retrofitted with early heads as the date stamping matched. Someone with more experiance may chime in but im pretty sure all ROW SC engines had 39mm ports.



Steve