When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
First off, want to apologize for the long thread about to happen:
But here I am, about 2 months out from delivery of my first Porsche (95 C2) and I am already losing my mind figuring out things I can do to personalize it. Being completely OCD like most people here I imagine. One of the first things I am going to do is take on the challenge of designing and manufacturing my own custom exhaust.
A little backstory, I plan on making it out of Ti, because well, Ti is friggin cool! The main problem I am having is narrowing down dimensions because I do not have physical access to my Porsche yet! Please see attached picture, ignore my terrible 2 minute fusion design, it was just for clarification.
As you can see, it's still in very rough shape (very rough shape obviously from the drawing above lol), but I plan on shortening the exhaust exponentially from stock. The main question and concern that I have is how much room I will have for the muffler.
Muffler: So, my whole build is about weight savings, I want to be able to put 2 plywood wings on the doors and have it take off into the stratosphere. So because of this, I want to make the muffler as small as possible, however not so small where the flat six screams at 600 rpm. I am going to have a mix of perforated tubing with fiberglass insulation and other sound absorption techniques like delta plates. I want to get down the dimensions so I can start CFD simulation. Anyways, getting to why I am making this thread.
What I need help with is seeing the dimensions of the engine bay. Engine to bumper, rear wheel to rear wheel, etc. etc. etc. I've looked at pictures but it is really of no help, would someone know/be willing to take some pictures and take some measurements on their 993 for me? The more the merrier! I would be so appreciative.
Probably best to wait till you have your car in hand. Hopefully you have a garage and a car lift to have complete access to get your dimensions. You may want to consider welding up a steel mock up before cutting titanium. This also might be a trial and error exercise to get the fit, sound and performance you are looking for.
Well, I'm on the verge of doing this myself (full Ti) with heater box retention. Unfortunately, dimensions are not going to help you very much at all. I'm experienced in motorcycle exhaust building and jig creation.
The exhaust setup on these cars fits within very tight confines and all sorts of angles (which vary from left to right side, btw). Rough measurements are not going to get you anywhere, as 911's are unlike most cars. The only way to really go about this is to take the headers and stock cat off the car, build a jig around the flanges and work backwards from there, keeping things within the dimensions of the stock setup. Alternatively, build in place without a jig.
There's also a lot of variables to consider. Are you ditching the heating system? Heat crossover tube? Heat shields? Way too many variables without digging into the car first hand. Also with your setup, you'd need to modify the bumper anyway.
Hi Blake,
Would you consider contracting with one of the 993 aftermarket exhaust suppliers who have already worked out the dimensions in stainless to fabricate the parts in Titanium for you. They may not have the expertise in working with Titanium but if you have such expertise maybe they would be willing to collaborate with you to learn how to work with the metal.
Andy;-)
If cost don‘t matter (10k with valves, heat and cats plus tax and shipping) Celeritech might be an interesting alternative. They do a 3D-scan of your engine compartment at your shop, custom design a truly equal length exhaust system on their CAD system, and manufacture it for you. They guarantee a perfect fit.
Exhaust modification for 993 is really tricky, specifically on the headers.
What do you want?
less weight / more power / more sound ... or a combination of it.
As said, modifying the headers can quickly lead to loss of performance!
For the rest, there are a bunch of possible modifications. If you want a center muffler, a Ti GT3 muffler is an option ...
Custom-built headers - GT3 4.0 titanium center muffler - Titanium exhaust tips - Capristo exhaust valve control (ECU controlled)
Holger, what diameter tubing did you go with on the headers? Looks bigger than stock. I believe stock is close to 1.75" (MM equivalent) on each port maybe even slightly smaller?
The tubing on the inlet side of the stock cat is also ~2.25" but most aftermarket x-pipes seem to bump to 2.5" tubing there.
I'm on the fence about equal length headers. The stock ones are not equal and there is allegedly much support that the stock headers are "very efficient". I'm leaning towards unequal length headers, as essentially, my goal is to mimic the stock system as much as possible, retain heater boxes (unequal header tubing aligned side by side makes this easier to build a box around), eliminate the cat but keep a mild x-pipe merge. Not super concerned with max power or fully optimized design. I would like to make it all out of Ti because I want to save weight and change the tone of the exhaust note. Also, it will be a fun project as I've never built a Ti exhaust, only stainless. We'll see where it goes.
If you're doing that center-muffler configuration, you should consider a Magnaflow muffler (#12468), a two-in, two-out x-pipe, with 18" body length. I've tried a GREAT many cat/muffler combinations, but back when I ran 2 turbos into this muffler, my car never sounded so good in any other setup. Seriously great. Might be a smidge loud without the turbos, not sure.
02-10-2021, 05:57 PM
993 Custom Exhaust Dimension Help
