3.6 to 3.8
 

Was just wondering what options did you guys go with I am thinking slip in 3.8 mahle kit. But not sure what I wanna do for the heads ,cams etc.. and don't wanna go too crazy lol.

You can do that, or you can get a 80.4 stroke Porsche Motorsports crank and also get to 3.8 and have a much stronger bottom end. Of course you will need rods as well, but all in all more torque on this option.

4.0
 

I am in the middle of that now, you would need the crank,rods,I/S assembly and oil pump, very pricey !

Mike Bruns

4.0
 

I am in the middle of that now, you would need the crank,rods,I/S assembly and oil pump, very pricey ! Also there's no provision for distributor drive

Mike Bruns

If you have a core layshaft you can machine the spacer off the crank and use your old gears / pump / etc.

Easily done.

Pic attached, machine that area just like the rest of the snout, boom, you can use all your old stuff. I personally don't care about a distributor....

My advice is to spend the money and build the best engine you can for the budget you have. That may be an engine with the existing displacement. As you go bigger you lower the VE often, and the costs go up. A better 3.6L engine is better than an average 3.8L engine, and a better 3.8L engine is better than and average 4.0l engine.

For example, instead of spending $$ on a 4.0l crankshaft, use that money on making the parts needed for a 3,8L engine, better. Often the choice to build larger is a itch that has to be scratched. It always sounds good to "say" I have a 3.8L or 4.0L engine, but the truth is, you could have made what you already have , better.

The aftermarket business has historically built larger displacement engines to gain some extra performance due to the fact that there has not been much available to build better stock sized engines. There are parts available to make these engine's bigger, but not better. What typically happens is, everyone ends up with the exact same engine and performance. Usually the engine's VE is sacrificed, but some torque gains are had with the larger displacement. Parts will fit together but nothing is designed to work together to produce a higher VE.

The aftermarket has relied upon certain parts suppliers to provide "hot rod" parts, often just their version of a copied part. These companies are not in the business of developing an engine, rather building their version of a part supplied as an alternative to a stock part. Connecting rods and pistons are perfect examples. These companies will build anything you need, but to expect them to develop a Porsche engine will not happen. They are in the business of selling parts only.

Ask who ever is going to build your engine (yourself if that who it is), how can you make what I have better and why. An good performing engine is the sum of its good parts. A poor performing engine is the sum of its bad parts.

all the parts in my engine is pretty much done at 195k, that's the main reason I went 3.8 ..

Is there a way to modify a 3.6L stock 964 engine to give 300 RWHP without changing the internals?

yes, add 5 psi

I have a 3.6, a friend has a 3.8. We have roughly the same spec engines, same cams, headers - but different, aftermarket EFI - but different brand.
We are less than 10hp from each other. I don't think that a 3.8 is worth it unless you get it free or need to change jugs.

I'm at 282 with only cams and slightly ported heads. I think I have a few hp still on the table with a better muffler based on how fast the power drops off after peak.
300 would be hard, perhaps with E85 and a little more timing.

I don’t like how heavy the 3.8 pistons are. Search for a good used set of 3.6 P&C’s, save money for cams, springs (with Ti retainers), VRAM (if you don’t have it), back date cam timing (really helps ensure accuracy) and drop $$$ on 9m heads or whoever has the latest and greatest.

5lbs is barely a tickle... SEND. IT. ALL. THE. WAY. :D

My 3.6 puts 310 to the wheels. JE Coated pistons, DC24 cams, RSR headers/ straight pipe. Can spank most NA 3.8's out there. Downright scary on a 2200 lbs car with 15 inch fuchs.. it would scorch tires on first gear without touching the clutch.

for those who seek torque, and if you are willing to give up some top speed, the most cost effective way to get there is to re gear your tranny with short ratio gears.. or even go down a size on your wheels/tires.

he said 300hp! :D not sure i'd be game to add more without internal mods haha

Now that’s a fun combination! I have 300whp in my 2,000lbs Miata Track Car and I beat the snot outta just about everything.

Let’s see that dyno sheet. I run the DC21’s in my 993 turbo conversion and would love to see the difference in the shape of the power curve.

My setup is pretty simple 3.8 p&c and jugs
Refresh crankshaft, oil pump , regrind cams to rs spec ,aasco valve and ti retainer , refresh heads to newer style. Dmf and new clutch. SW chip, fabspeed headers ,race cats with cup pipes.
Wondering if its gonna make a difference from 3.6 stock.

In production models (RS) the 3.8 upped the power from 286 to 300, possibly the mapping wasn't the same between the normal 993 and RS.
But your other stuff will make a huge difference.

What you really need with your setup is a set of bigger injectors. A 3.6 with some mods almost always push 300 and then the injectors are really maxed out.