JPS

So it seems I'm at a minimum of a top end rebuild, though I'll have to dig in to see for sure.

So, confirmation aside, assuming I do need one, it then begs the question of whether it makes sense to do something more.

One of those options is a 3.8. I never would have pulled a healthy engine to do it given the cost, but given the cost I'm likely to have to sink in just to get it back to stock, it does make the marginal cost much less.

But in reading here, it seems there are differences, some subtle and some not, of what you can/should do.

Constraints: 1995 993, 74k miles, 12-15 track days in Red annually, but also street the car extensively. I've already reageared and done MCS suspension (where I would put the money if I haven't already).

What are the needed components to do it right, but not monster? I get that the slide in P/C aren't the right answer, but what is?

JPS

Looks like I'm going to have to do a minimum of a top end. Diagnosing but gathering options.

What's the collective experience of RS Cams on otherwise stock rebuild (assuming chip and such), vs. full 3.8?

Trying to assess if 3.8 is worth the extra $$, given I may be relatively deep in there. I posted separately about the 3.8 bits.

Moot if the rebuild isn't needed, but trying to have quick answers once I see what's needed.

Gt3stig

Give Steve wiener (rennsport) a call, he'll point you in the right direction.

Talking to Steve is like talking to.....

Steve Weiner-Rennsport Systems

If you do a 3.8, you want to use Mahle 3.8 (102mm) RSR P/C's. These are thick-walled cylinders with 109mm spigots that require the case to be machined.

JZ98-993

Curious to see the responses you get here as I'm evaluating doing the same on my 95. Based on my research there are many different opinions on this topic, one that seems to be consistent is you can't just add P&C's and expect any noticible gains. Really comes down to intake, heads, cams and ECU.

Have you looked into the 9M stage 3 package? Essentially 9M heads, cams 3.8 and since you have OBD 1 they can map your ECU (No option for US OBD2 which is why you don't see many in the US). Numbers I've seen is ~$15k for the entire package US and hp in the 360-380 range. Seems to be a pretty compelling package. Interested on others thoughts on how best to approach this.

Cemoto

I'm very pleased with the 3.8 RS spec build in my car. It is my favorite 993 to drive (turbo is different experience) hands down. The build did take away any thought or desire for a re-gear (which you already have). Not sure how it would be coupled with a re-gear, maybe Steve can chime in here.
There is a long list of recommended add-ons, some of which you may have already, such as headers, sport cats, etc.
A build such as this is not something I would consider having a local shop do. You need to give it to someone who has a proven track record of these builds (No pun intended there), otherwise it is an experiment on the builder's part. ECU mapping is key to take advantage of the build.

In my opinion I would say go for it! It makes for a very special car that will always put a smile on your face.

Regards.

.

Mark in Baltimore

Merging this thread with the other 3.8 thread you just started so information can be found in one spot.

Bill Verburg

Staying w/ mostly standard configurations here' what you can expect from
a 3.8RS vram a 3.6 n vram build w/ RS valves and cams and a stock 993 nvram



All 3 are reliable long lasting powerplants

Beyond that you need to raise the rev limit, which means a beefier bottom end, wilder cams and hopefully lighter, stronger components all around. This gets really expensive and MTBR goes down as revs go up.


Gearing & tire are a multiplier on the engines native torque curve.

Mine is a 993RS w/ 993RSR/Cup trans, and much lightened chassis extremely satisfying. 265/35 or 285/30 tires are going to be quicker than 275/35 because of shorter rolling radius.

GBX

Great thread. Been wondering the same.

Cemoto, who did your rebuild?

Spyder_Man

That added low-end torque from the 3.8 option sure looks fun to me. Seems like the 3.8 really changes (improved the torque band) while the RS Cam/Valves option makes for a similar to stock 3.6 but slightly better experience.

Bill Verburg

It's the combination of extra displacement and vram, add vram to a stock nvram 3.6 and you get a nice bump in low to mid torque

Spyder_Man

Bill do you happen to have a similar torque curve comparison on hand for non-vram vs. vram 3.6 engines to tease out what change in torque is intake related and what is displacement related

EDIT - I found a couple of graphs that help answer the question that I posed to Bill:

Martin S.

See the enclosed pdf.

Spyder_Man

I found this website to be very useful in explaining engine rebuild options:

http://www.instant-g.com/products/36...h-about-3-8s-2

Especially the table at the bottom comparing torque and hp gains for different tiers of engine upgrades.



If anything this just makes me want to install a V-RAM intake while the engine is out. They have a great write-up regarding the vario-ram too:

http://www.instant-g.com/products/36...ation/varioram

Tlaloc75

Great site, thanks for sharing. Lots of interesting commentary on vram motors. Makes me happy to have one!