My M491 needs more vroom building a 3.2 vs 3.6?

[Classic11]

Dear Pelicans,
I would like to get a conversation started and needs some advice from others that have been down my route. I have a 84 M491 with a recently rebuilt pretty stock 3.2 and 915 tranny. I love the car and performance, pulls great for a 3.2 but want to take the numbers matching engine and tranny, put it on the shelf after I built a replacement. What I have to choose for replacing my engine is:
- 1987 3.2 complete engine with harness and DME (no muffler)
- 1991 3.6 complete engine (no harness no DME, no muffler, no headers)
- 1977 915 tranny (cutout for 3.2 speed and rev sensors)

I am debating what engine to use for getting decent and reliable power, I am not looking for 300HP. I would rather choose top end power over bottom torque.
I have built several 3.2s and know them in and out, the 3.6 is new to me. Of course biggest question is getting the electronics around it figured out etc… While I am looking for HP, I want to keep the expenses in line also, what i mean is a cost comparison between both options:

#1 possibly building a 3.4 out of the 3.2 using existing electronics
#2 fitting the 3.6 to the 915 and getting the electronics adapted into my 1984 car

Any feedback is appreciated.

[Trackrash]

The 3,6 makes the most sense, from a power standpoint. However, with a chip and headers you are right at 300 hp with stock internals on a 3,6. Lots of torque as well. In a light weight car you will have neck snapping acceleration.

I know a couple of guys who used to AX with me that had Carreras with 3,2s and only headers and chips. They had surprising performance.

Now if you are looking at making power above 7k rpm, that is another story.

Loosing weight might be something to think about as well.

[Bill Verburg]

Originally Posted by Classic11

Dear Pelicans,
I would like to get a conversation started and needs some advice from others that have been down my route. I have a 84 M491 with a recently rebuilt pretty stock 3.2 and 915 tranny. I love the car and performance, pulls great for a 3.2 but want to take the numbers matching engine and tranny, put it on the shelf after I built a replacement. What I have to choose for replacing my engine is:
- 1987 3.2 complete engine with harness and DME (no muffler)
- 1991 3.6 complete engine (no harness no DME, no muffler, no headers)
- 1977 915 tranny (cutout for 3.2 speed and rev sensors)

I am debating what engine to use for getting decent and reliable power, I am not looking for 300HP. I would rather choose top end power over bottom torque.
I have built several 3.2s and know them in and out, the 3.6 is new to me. Of course biggest question is getting the electronics around it figured out etc… While I am looking for HP, I want to keep the expenses in line also, what i mean is a cost comparison between both options:

#1 possibly building a 3.4 out of the 3.2 using existing electronics
#2 fitting the 3.6 to the 915 and getting the electronics adapted into my 1984 car

Any feedback is appreciated.

Keep looking for any of the following a '95 US 993 w/ harness and DME or a RoW '95-98 993 w/ harness and DME or any 993 w/ after market EFI such as Motec w/ harness and ITBs, this later will be more flexible in subsequent choice of cams and rev limit

here's what you can expect in terms of rear wheel torque





torque at higher rpm is hp

[Dan J]

3.6 for sure. I've done both A hot rodded 3.2 (3.4 ,3.5 ) will never have the drivability and reliability of a lightly modded ( chipped,exhaust) 3.6

[BoxsterGT]

For a 3.6 conversion I can help with the Fuel System.

I have E-85 Rated Crimped Metric Hose with my "Direct Connect" custom fittings that make this an easy install....



Also available with the same E-85 Rated Metric Hose and Braided SS cover....



For information, please email me: len.cummings at verizon.net

Thank you.

Len

[Fly911]

Why don't you build a 3.6L on your matching numbers 3.2L? That would be less trouble and same price as buying, fitting and modifying for a 964 or 993 engine... And you will get a "new" engine and not an unknown used one.
Get a 993 crank shaft (fits right in) and 100mm LNE cylinders with JE or Carillo pistons, Carillo con rods, and 993SS cam shafts. Extrude hone the intake, and let Scarseller here on this forum do the Motronic upgrade with his bespoke ECU modifications and MAF sensor. You will have at least 300Hp...
The look of the engine bay would be unchanged, and you will have a 100% matching numbers car. Also, I would have re-geared the 915 with lower 2-3-4 gears, and kept 5th original for highway cruising.
You would get a car that would blow people away, and nobody would be able to spot the difference from an original 3.2L!!!

[safe]

Originally Posted by Fly911

Why don't you build a 3.6L on your matching numbers 3.2L? That would be less trouble and same price as buying, fitting and modifying for a 964 or 993 engine... And you will get a "new" engine and not an unknown used one.
Get a 993 crank shaft (fits right in) and 100mm LNE cylinders with JE or Carillo pistons, Carillo con rods, and 993SS cam shafts. Extrude hone the intake, and let Scarseller here on this forum do the Motronic upgrade with his bespoke ECU modifications and MAF sensor. You will have at least 300Hp...
The look of the engine bay would be unchanged, and you will have a 100% matching numbers car. Also, I would have re-geared the 915 with lower 2-3-4 gears, and kept 5th original for highway cruising.
You would get a car that would blow people away, and nobody would be able to spot the difference from an original 3.2L!!!

You forget adding a second spark plug, other vice a decent plan.
I would skip the Motronic and go straight to an aftermarket ECU, they are so good and reasonably priced these days, it would make COP a much better alternative to twin plug distributor.

[BoxsterGT]

I have a nice set of 3.6 TWM throttles with only 7 hours of run time....



I would like to sell if you decide to go the 3.6 hot rod way.

Len

[Classic11]

Hello all, thanks for the input, it got me thinking, I did a good bit of research on the 3.6 swap and costs along with it. Kit (instant G) is reasonably priced i think, the 3.6 i have is still the older aluminum intake version and i dont konw if it received the head ugrade or not, If i need to rebuild the 3.6 with all the good stuff along to make it the newer version I am in for big dollars. I kind of like the idea of building a 3.6 out of the spare 3.2 engine I have.
How much are the following parts roughly when bought at a normal price?
- 993 crank?
- 100mm LNE cylinders with JE or Carillo pistons?
- Carillo con rods?
- 993SS cams?

Regards,
daniel

[Fly911]

Classic11/Daniel

I would install the spare engine in your car, and build the 3.6L on the original and matching numbers engine. You will then have a matching numbers car, with all the modifications invisible to the naked eye, but blow everyone away with its performance!

I would assume the pricing would be:
993 crank shaft, $2,000
100mm LNE Nickies with JE or Carillo pistons, $5,000
Carillo con rods, $2000
993SS cams, $1000
Extrude hone the intake, $1,000
Porting the heads and twin plugging (not necessary if you keep 10.3 compression ratio...), $2,000
Modify the crank case for 100mm cylinders, $500
964/993 dual distributor, $???
964/993 oil pump, $1,000 (?)
Motronic mods by Scarseller/Sal with bespoke tuning, MAF and new modern injectors, $2,000
LWF and clutch, $2,000 (?)
You would need a better exhaust. Depending if you want heat or not, the German company Eissenmann makes SSI like headers/heat exchangers, but with bigger primary tubes for 3.6L to 3.8L engines. Or find used Fabspeed or Billy Boat equal length headers.

You should be able to get a plug and play 3.6L "brand new" matching numbers engine for around $20k (parts). The actual build cost would be around $5k.

You could then sell your spare engine, you won't need it!

[winders]

Why would you not use a GT3 crank instead of the 993 crank?

[Fly911]

Winders, I'm using a 997 GT3 crank in my build, based on my 3.2L. But my Carrera is a dedicated track car, and not a street car. The GT3 crank is way more expensive, and for an engine that most likely would never see more than 7,500rpm, the 993 crank is more than good enough.

Both the GT3 and 993 cranks are 76.4mm stroke. If you want to go all the way with a 3.2L build, you can buy a OEM or aftermarket 80.4mm crank and 102.7mm P/C set from LNE, and build a 4 liter. But cost escalates exponentially. And it's always the thickness of your wallet or the size of your bank account that determines how many horsepower you will get out of your engine.

For Classic11, I believe his goal is to keep his M491 as original as possible, but with some subtle performance modifications that would enhance both driving experience and value of the car.

When you have a 35 year old classic 911 that is approaching six figures in value, you really need to understand the do's and the don'ts when you start modifying. If you want to keep or enhance the car's value, you need to keep it a matching # car, and keep the modifications invisible to the naked eye. Like changing the engine (and gearbox) internals, upgrade suspension (and brakes), keeping the Mortonic ECU, but with bespoke upgrades and modifications and modern fuel injectors from Scarseller (no affiliation). Done right, not even scrutiny from the judges on a concourse event would reveal the modifications. And only the owner would know why his car blows everyone else away!

[Glenfield]

Fully expecting Winders to weigh in on the GT3 v 993 crank. Actually thought they were cheaper or same price?

On resale value, I’m not sure he’d be better off for building out the stock engine into a numbers matching hot rod vs swapping an engine in and properly storing the original. The buyer of a stock m491 that is paying a premium for stock isn’t the chap that will throw money at returning the engine to OG. A rarer car and that calculus would be different but think you’d have to take a very bullish view on where m491 values will get to medium term to underwrite this.