Mike J

Anyone have a 993 Turbo in the Vancouver/Seattle area equipped with Fabspeed X exhaust below also equipped with Fisters or stock mufflers (prefer no supercups but will listen to those in a pinch) that I can listen to? I am trying for a specific sound combined with high flow - their design is close to the way I would build it, and I would prefer to purchase the exhaust and focus on other projects. BTW, I think the cross section in the X pipe is a bit small for what I would have preferred which is why I want to hear it.

The exhaust that I am trying to duplicate and possibly improve on is on Knight's car - it appears to be a custom fabrication which provides one of the best idles i have heard on a Turbo, as well as very good sound at speed. The car has great power, but it has not been dynoed so cannot really say how efficient it is. That exhaust totally eliminates the boat putt-putt-putt idle of the stock exhaust, its more like a smooth burble.

I have listened to examples for this X pipe on Youtube, but I have learned that there is so much variation in the quality of the recordings that its suspect - and what I have heard so far (usually with Supercups or bypasses) is not the sound I want.

Interestingly enough, in a conversation with Fabspeed, they will not allow returns due to things like sound, to quote:

While we do warranty defects in the craftsmanship, we do not warranty subjective attributes – sound, tone, etc. Rest assured that we have sold many of these specific systems and have many happy customers utilizing this system along with numerous other configurations that we offer for the 993TT.

Which is just great, everyone has some unhappy customers, but regardless no way am I spending this sort of money without hearing it personally. If I cannot find one to hear, or I do and it sounds like a boat, time to get the TIG torches out and get to work ...

Cheers,

Mike

PS crossposted this in the 993 Forum - sorry for the duplication ...

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OverBoosted28

From the pics that I've seen, it looks as though Knights car has a N/A cat made to merge both sides and fit. Hope you figure out a cost effective way.

Mike J

Close - it's the factory Turbo exhaust cats joined and then exit ports built out the bottom - but great guess! . Its not just a pipe joining the two sides, there is some exhaust routing happening internally. There is a bit of a ground clearance challenge with this approach as well.

The issue with that exhaust (and likely what makes the sound smooth) is the two cats are facing each other and while they have a bit of deflection structure in between that is likely not the absolute best design for efficiency, the mixing of the two exhausts is quite substantial.

Cheers,

Mike

OverBoosted28

That was the biggest challenge (along with clearance issues) that I was trying to resolve. How to mix them into a harmonic blend without both pulses (basically) hitting each other. Although the Fabspeed system works, I am sure it doesn't really mix both sides. The X-pipe area is pretty small to be effective. Each banks pulse takes the easiest route, which would appear to be the "U" bend as opposed to squeaking past each other at the X. Packaging is the most restrictive issue in effectively mixing each bank. That's the dead end I ran into. Without going full blown center custom mixing chamber, I didn't see much option. Hope you do.

Mike J

I have exactly the same thoughts, but you are ahead of me! Good mixing boxes allow for much more room since they have the room, like the example below - but this space is very tight. Did you consider going horizontal, i.e. like using two U pipes but spacing them horizontally apart and building a custom chamber spanning between the pipes so there is more mixing space? The flows would be going in the same direction so that is good.

Cheers,

Mike

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OverBoosted28

I sorta got sidetracked and lost my drive when I realized the gain wasn't really gonna justify the amount of work to do it right. Without getting too deep into it, there's really no gain other than the sound of the idle. If I had better resources, I might still try it at some point. Just didn't want to keep spinning my wheels and get nowhere. I really was hoping you'd develope something I could replicate :-)
Send me an email if you still have my address and I'll send some drawings of what I was looking towards. Let me know if you don't and I'll PM it to ya.

Ridin Dirty

IMO putt putt is virtually eliminated by an x pipe. Preferably one with a larger mixing aspect than Fab's has. I ended up with a Dach and some good ole RSR (Robin Sun) mufflers. I have no putt putt and I know what you mean by that sound profile.
I also have no drone....none and that means 100 out of 100 people riding in the car stating "no, no drone in here".
It's just another testimonial...... kinda meaningless....even a video load is meaningless too b/c we have all heard a great video and went right out and purchased exactly what they had it and it wasn't the same. If your in as deep as we are it definitely happened and likely happened repeatedly. I have a PHD in 993 mufflers now. Even my set-up that I just proclaimed as my current holy grail has a God awful video of someone else with the exact same set-up and it sounds NOTHING like mine. It's almost a comedy of subjectivity and frustration.
I'm satisfied but never content. And actually Mike you should continue your line of thinking b/c it's sound (no pun intended) remember you were the one who said long ago an "x pipe eliminates putt putt" and you are indeed 100% correct; mixing eliminates putt putt. The more mix maybe maybe the better and I think your going to find out.
Tonight I'm stickin a scope in my RSRs

OverBoosted28

Can you post some pics of the X-pipe you have? Didn't know anyone else made them, other than Fabspeed. If not can you advise on where you got them? Thanks

Mike J

Hey, first dibs man!

Ridin Dirty

will pic this weekend for you but its just like this one (hope this even works...i'm really bad at posting pics here).
.......So that's why i can't find any info on it....out of business? this was a straight ebay purchase and i paid $400 for it. i think its worth more now since others call it a "piece of art"..... fabs was prettier....but this is "beefier" almost/actually i think "is" custom made when they made them.

I also have fab headers, custom bypasses/no cats, and the RSR mufflers (which i couldn't see into from the tail pipe with my scope....i have to take em off to peer into them).

Kevin

With the flat 6 engine with separate banks an "X" pipe is not preferred. The merge pipe with 180 degree bends with a engineered aperature (merge window) tuned on the dyno. Yes, there are many "X" pipe systems out there> look at the 996TT. However, the cross section cuts down the flow, it is a bottleneck. The merge is a better flowing design and yields better midrange torque. Build the system out of 3.0" piping. If it's just for sound 2.75"

Mike J

Thanks Kevin - I think you are saying is the Fabspeed approach of a cast piece with two 180 degree bends and a tuned port between them is the best approach?

I understand that the cross section of any of the pipes should not be compromised so no squeeze points are in place, which means that any merge system with two pipes needs at least the capacity of both of the incoming pipes.

When I look at the stock system, the flow is really good to the cats, and then it gets reduced to a less than 2.5" pipe after the cat all the way out ...

Kevin, what do you recommend as a good upgrade from the stock system, or is the stock system that efficient?

Cheers,

Mike

Kevin

To BEAT the factory system with 130mm 100 cell cats you would need to increase the piping to 3.0" or 2.75" minimum. A 2.50" system will flow LESS than what I have mentioned. Looking at the pictured system you would need to verify the merge aperature AND piping diameter.. 2.75" would be ideal.

TB993TT/Toby posted pictures of his modified CAT's and piping years ago..

My opinion is that the 993TT has a unique sound, the sound that you folks are looking for is MORE 996TT/997TT (shame on you -smile)..

Ridin Dirty

Don't think I've ever uploaded a video and this is at night so my disclaimer is its just the sound I was interested to convey.

So mike was wondering if the x pipe reduces or eliminated the putt putt sound and I believe that is eliminated

All my mods:

1. Headers
2. Dach x pipe
3. Cat by passes
4. Rsr mufflers
5. 996 S tips

This is loud, very, very loud, BUT no cabin drone, and this whole drone/resonance is a subjective thing BUT AGAIN absolutely no drone, almost like a Stock 993TT inside the cabin. "Sounds" impossible but you could almost whisper to your occupant inside while driving.

I also panned around and turned the lights on thought I'd show off my HID driving lights and LED corner lamps with integrated switchback turn signals.

Again to reiterate video is crude, and I think it's sideways. I was just leaving my business warming her up, she's tucked back by the dumpsters in her own little corner. I'll post another of underside in the daylight and right side up....ha

Joe

OverBoosted28

Sshhzzzamm, ya gotta make one with a little revs. Slowly go from idle to about 3k for a bit. Nice. Did u mod the 996 tips urself. I was thinking of making some.