bfrank1972

Ok bear with me and my newbie questions - I'm looking to purchase a 964 or 993 in the next couple of months. To me, I love the classic shape of the 964 more than the flattened nose of the 993. But there's one thing that always gets me - I've heard a bunch of 964's and 993's with various intake/exhaust configurations (including stock). While the 964 sounds great at idle and mid revs, the 993's always howl at the top end. Even the 95's sans varioram sound better - is there a reason why or am I smoking crack? I thought the motors were pretty much the same.

Bill Verburg

The 2 big influences on the sound of an engine w/ essentialy the same internal configuration is the intake and exhaust configurations.

Open up the intake air by drilling or otherwise removing parts of the cover will add some intake drone.

the stock 964 uses a convoluted and inefficient exhaust setup where the 993 uses a semi header design w/ separate mufflers. put a set of headers, like say the current Fabspeed design and a free flowing 2x2 muffler, again like the current Fabpreed and the exhaust note will be much more similar. The Fabspeed setup will of course be louder unless the 993 is altered, say w/ a dual cat bypass. It can be made even louder by using the cat by pass w/ modified mufflers.

Rocket Rob

I'm not an expert but I can tell you that the motors in the 964 and 993 are very similar but the key difference is the exhaust. Your ears are probably sensing that.

BlueHeeler

You are not smoking crack, well maybe you are, that aside you are not wrong. The motors between the two are similar and exhausts are very different.

This is stock 964:
It is two 3 into 1 manifolds. Crossover pipe for 3 of the cylinders to mix with the other three at the cat, two more mufflers in series, and tail pipe. All exhaust pulses are mixed early.



This is stock 993
It is two 3 into 1 mixing at the cat*, then separation to parallel twin mufflers.


*I am not 1000% sure that cat mixes, having never dissected one.

TBH though I would not let exhaust note drive my decision between a 964 vs. 993. 964/993 are very different cars in more profound respects than exhaust.

The Stig

Tricked out 993s with RSR Supercups or Fabspeeds sound incredible - but they verge on sounding like a powerboat near idle. They sound much better at full chat. The Dachs X pipe with 200 Cell Cats is lovely too.

Me? I pulled the snorkel off my air box, removed the engine tin and added a G-Pipe (removed secondary muffler, #9 in the diagram). Its motoring heaven IMHO, but others may fancy other set ups. Mine cost a whopping $100.

Good luck in your search.

Cliff

pchak

Cliff,
Could you elaborate a little more as to what you did? G-Pipe is a new one by me...
thx!

Ritter v4.0

Doesn't get better than this I don't think:
http://www.youtube.com/watch?v=5baipiffR4M

Scroll ahead to 1:30 and listen to the end. If it sounds like this thru cheesy PC speakers can you imagine in real life? Its subjective but I've never heard any car that sounded this good to me.

The Stig

The G-pipe or secondary bypass is actually a U-shaped piece of tubing that replaces the secondary or final muffler. It connects to the exit of the primary muffler (pic #8) and the end pipe (pic #10).

You save about 25lbs by removing the secondary and release a fury of noise. You will set off car alarms in underground parking lots. And since I'm a child, this amuses me to no end.

There are lots of clips on youtube. But you should hear the racket it makes once the engine is up to temp in person. Some prefer to bypass the primary, but this is a more expensive option and gives off a slightly different tone.

BlueHeeler

G-pipe is a U-turn circumventing the secondary muffler number 9. The exhaust goes from 7 to 10.

The other easy option is replacing the primary #8 with a Cup pipe.

The g-pipe offers marginally more hp and noise and the straight pipe removes significant weight from the rear improving handling.

Horses for courses I suppose.

bfrank1972

Jeez convoluded is right - maybe they should have just run it all the way to the front, through a few loops and kinks and all the way back to the rear again

Seriously these pictures are worth a thousand words - the 993 looks much simpler.

And no sound is not my sole basis for decision, but it's important to me - from what I know so far (from reading through the archives) the 964 has a less complex rear suspension. Some say the 993's rear suspension is overall better, but I've read many like the 964 in that it combines a bit of the 'old school' feel with a much better suspension setup and the 3.6, where the 993 feels more on the modern side.

I've driven both briefly but not back to back (about a year apart). From what I remember the driving experience of both was still very 911. BTW I'm one of those guys who used to own a 73 911S, said they'd never sell it, sold it, and currently kicking myself. I love the old feel but I've been pretty impressed with how the newer aircooled cars are able to retain alot of that character with the newer techl, refinement, and power.

Anyway if I do go 964, I'll likely be doing some sort of header (with exchangers) setup to replace that crazy emissions thing the factory did.

BTW anybody successfully adapt a 993 exhaust to a 964?

Regards,
Brad

P.S. - this forum is the best

Bill Verburg

The 993 headers on the right hand side have a stud pattern rotated 90* from that used on 964 and earlier cars you can cut and reweld the flanges but it's alot easier to just buy a set of headers.

another issue w/ 993 headers on a 964 is the angle of the outlet flanges, they are set up to have the left go right and the right go left. This is fine on a 993 w/ dual sidemount mufflers but the 964 fenders don't really have room. I have some pics of this done on a 964 3.8RS w/ the wide turbo fenders but even there it doesn't really fit.

lastly the heat is different, it can be adapted but it's a lot more work.

I like the sound of my motor boat
3.8RS it sounds even better on the move


The only downside of the single rear mounted 2x2 mufflers is noise, they just don't have the internal volume(Fabspeed has the best I've heard in this regard) and a tendancy to resonate in the mid 2k rpm range(again Fabspeed is best in this area too, though you may want to get feedback from some of the guys using the current samples, I have just been in cars equipped w/ older versions. My own car has a very old design Fabspeed/Flowmaster which is very loud, I wouldn't recommend this for most people because of the volume of noise))

Bill Verburg

the cat has 2 parallel longitudinal inlets which go into a central coffee can like mixing chamber where the O sensor resides, the gases then exit laterally through the separate catalytic matrices to the respective mufflers.

BlueHeeler

Thanks, everyday is a school day.

demonfish

to make your mind up - here is a drilled airbox, decat, standard primary, and g pipe... THE best sound IMHO

http://www.youtube.com/watch?v=maghyuQedT0

or in car

http://www.youtube.com/watch?v=QMXwB3KTdrg

bfrank1972

Wow after reading about Fabspeed's header system I stumbled across this:

http://www.youtube.com/watch?v=vnSBl...e=channel_page

That's what I'm talkin about! Thanks all for, as the other poster said, the education

BTW I don't smoke crack, but the 911 is close enough...