914 2.0 > 3.0 GT Conversion, On the road! Options

[defianty]

Having also collected the front valance I could put the front together.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1559376325.1.jpg)

And with the drivers door fitted, it's really starting to take shape :cheers:

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1559376326.2.jpg)

[bigkensteele]

Stunning! (IMG:style_emoticons/default/beerchug.gif)

[Larmo63]

Wonderful build and fun to watch it taking shape.

(IMG:style_emoticons/default/smilie_pokal.gif)

[IronHillRestorations]

Looks amazing Stephen!

[defianty]

Being the original door to the car the drivers side window regulator went in without a hitch and this time I took a closer look at the height adjuster and concluded that something has to be wrong with the passenger side as no amount of adjustment makes any difference to the height. Looks like I'll have to tear that one down again.

But great to get the drivers side operating perfectly and fitting well.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1559803434.1.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1559803436.2.jpg)

I also had to make an adjustment on the engine lid and couldn't resist this shot whilst I was there.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1559803436.3.jpg)

[porschetub]

Very nice love the pics....getting close (IMG:style_emoticons/default/smilie_pokal.gif) .

[bbrock]

This is pure porn (IMG:style_emoticons/default/drooley.gif) Can I ask what you are using to light your pics? Your photos are exquisite.

[defianty]

This is pure porn (IMG:style_emoticons/default/drooley.gif) Can I ask what you are using to light your pics? Your photos are exquisite.

Thanks Brent.

I don't use anything special. In fact all the photos are taken on my Google Pixel 2 with daylight or garage lights as my only light source. I never use a flash. If I ever want any depth in the photo I'll use the inbuilt 'portrait' feature as it blurs the background slightly which emphasizes the subject.

With a Google phone the photos are automatically uploaded to Google Photos which has basic editing built in. I usually just up the blacks and highlights slightly to add contrast to the images nothing more.

I spent 20+ years as a Graphic Designer, it's programmed into me to make pictures look good (IMG:style_emoticons/default/laugh.gif)

[Lucky9146]

(IMG:style_emoticons/default/silver914.jpg) You have come so far and it it is coming out fantastic!
Always great to see your progress (IMG:style_emoticons/default/beerchug.gif)
(IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/white914.jpg)

[defianty]

Creating a Sport Muffler.

I picked up a Leistritz muffler a couple of years ago on ebay as it was cheap and thought it would make an excellent candidate to convert into a sport muffler. I'd seen instructions over on Pelican on how to do this and just a few months ago the thread I had bookmarked was updated with a slightly revised design. So with those instructions I set about making the modifications.

Original Pelican Thread. Post 40. http://forums.pelicanparts.com/porsche-911...ml#post10058354

Here's what I started with.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707971.1.jpg)

When James' (23e Heure) GT conversion was finished the muffler fitted to the car originally had an awful, ear piercing drone so I swapped it with this one temporarily and it was much quieter for the run down to Le Mans Classic. So that confirmed my £70 ebay purchase was a bargain (IMG:style_emoticons/default/laugh.gif)

I won't go through every step as speedracer54 on Pelican did a great job explaining the process. However here's a few photos of the modifications of mine.

Cutting into the case.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707972.2.jpg)

Mask on!

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707972.3.jpg)

After a bit of cleaning.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707973.4.jpg)

Marking out the parts to be cut out.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707973.5.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707974.6.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707975.7.jpg)

New hole

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707975.8.jpg)

Part of one of the pieces cut out put into the hole so it matches the original at the other end.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707976.9.jpg)

Once this part of the pipe was cut I need to add the holes similar to the other section. Just look at how I managed to get them all perfectly in line and the same size (IMG:style_emoticons/default/laugh.gif) :oops:

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707976.10.jpg)

A couple of sections had to be sealed off to redirect the flow so with a cardboard template in place I could make the plates to weld in.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707977.11.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707977.12.jpg)

With the internal modifications complete here's how it now flows.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707978.13.png)

Finally I could add the distinctive twin outlet pipes.
(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707978.14.jpg)

After stitching it all back together and giving it a coat of silver/grey VHT paint here it is ready to fit to the car.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1560707979.15.jpg)

Can't wait to hear what it sounds like now. I've seen a couple of YouTube clips and a couple of first hand accounts say it shouldn't be too obnoxious but I'll have to wait and see. If it's too loud I'll treat myself to a new one and chalk this up as another learning experience.

[gereed75]

Very interesting and timely. I too am building a muff for my 2.4 six. I have seen this modded stock muff before in all the various threads. I am going a different route as I am starting with an essentially open tube, two standard inlets and will be going with the two outlets, but will be placing them closer together ala the Boxster look.

My biggest concern is also to control the inherent resonant drone at 2400 - 3500 RPM. I have a couple of ideas on how to do it. One of them concerns the common middle chamber that feeds the two outlets. I wonder if having this chamber common tends to increase the tendency to drone, or if it would be better to separate the two sides, with no common center chamber, see attached sketch.



As I fabricate, I will be able to build the center chamber either way, so When you get it mounted I will be interested to hear your feedback regarding drone.

Hoping Ben might chime in with some trade secrets

[mepstein]

You can also keep the stock end pipe on the muffler and create a rally exhaust. Cap off the GT pipes for long drives or driving out of the neighborhood.

[mb911]

Guys I have done 10 of these sport conversion s recently.. I charge 250 for doing the conversion. They are not to difficult.. That said I still have 4 of those GT 3 or sport mufflers that are super cheap @450 and a 2 in 1 out non quiet for $400 not that you are really looking for those but thought it would help you weigh out how hard you want to work on this. (IMG:style_emoticons/default/biggrin.gif)

[maf914]

Defianty/Stephen,

Thanks for the great photos of your work and the Pelican link. I think I finally can understand what the sport muffler modification actually does relative to the stock configuration.

My question is, do these modifications actually increase performance? Or is this a matter of sound, and perhaps appearance? Are there any dyno numbers, before and after, out there?

[mepstein]

Louder is always faster. (IMG:style_emoticons/default/biggrin.gif)

[defianty]

Very interesting and timely. I too am building a muff for my 2.4 six. I have seen this modded stock muff before in all the various threads. I am going a different route as I am starting with an essentially open tube, two standard inlets and will be going with the two outlets, but will be placing them closer together ala the Boxster look.

My biggest concern is also to control the inherent resonant drone at 2400 - 3500 RPM. I have a couple of ideas on how to do it. One of them concerns the common middle chamber that feeds the two outlets. I wonder if having this chamber common tends to increase the tendency to drone, or if it would be better to separate the two sides, with no common center chamber, see attached sketch.

As I fabricate, I will be able to build the center chamber either way, so When you get it mounted I will be interested to hear your feedback regarding drone.

Hoping Ben might chime in with some trade secrets

The guy who's method I followed adapted the initial sport muffler modification that was posted at the beginning of the Pelican thread. One of the reasons for change was to eliminate the drone and to quieten it a little. I believe he achieved this although I won't know this for sure until I can test it. That will have to wait for a few weeks yet.

[defianty]

Defianty/Stephen,

Thanks for the great photos of your work and the Pelican link. I think I finally can understand what the sport muffler modification actually does relative to the stock configuration.

My question is, do these modifications actually increase performance? Or is this a matter of sound, and perhaps appearance? Are there any dyno numbers, before and after, out there?

Good question and I can't say I'm sure about the answer. Obviously I'll have no before to benchmark against. I do think the muffler is now less restrictive so there may be a small increase in performance. To be honest I only did it for the looks and hopefully sound. Any performance gain would just be a bonus.

[defianty]

Louder is always faster. (IMG:style_emoticons/default/biggrin.gif)

Absolutely (IMG:style_emoticons/default/laugh.gif)

[gereed75]

The original 2 in 2 out Dansk Sport is just one step below straight pipes with very little internal baffling. From what I understand, it is LOUD.

This iteration is somewhere between stock and dansk sport in baffle department. Just by looking at it it should be somewhere between a stock muff and a Dansk Sport in both sound and flow. The bigger unknown is probably controlling the resonant drone. I just re-read the Pelican thread and “blee” reported “ no drone” with his shared, open to both out pipe center chamber.

I suspect this is a bit of an in-exact science, so until it’s run it is tough to know exactly. Good luck Stephen! Nice work.

Oh ya .... Louder - faster

[defianty]

Well I've conceded to defeat on getting the car ready for Brooklands 914/50. With a business to run and also now being back working full-time there's just not enough hours in the day. I've enjoyed every part of the project so far and I knew if I carried on with what little spare time I have now I'd start to hurry unnecessarily and end up working on the car whilst tired and that wouldn't be fun and after this much work I didn't want to start cutting corners. I was a little disappointed at first but the few hours I've had on the car over the last couple of weekends were enjoyable and it'll still be done with time to get it on the road before the end of the summer.

Last weekend I finally made up some fuel lines and got them fitted. A nice improvement over the original plastic ones.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i.postimg.cc-6621-1561568626.1.jpg)

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