Woody's build thread

[itsnotanova]

Sorry guys but I was being a new father. Over reacting and nervous about everything. I just took it for a spin and it stayed on the 8 the whole time. Like I tell a lot of people. I'm an expert at taking them apart but not so much putting them back together. I did have someone try and race me already.

[Ben006]

Originally Posted by itsnotanova

Some guys are talking about having them hotwired and with a toggle switch so they can manually activate them.

I'm working on an easy DIY for that, using 4 remote relay socket and a 3 position switch
I'll post it on the forum when I receive the sockets

Good job with your car!

Ben

[steved0x]

Originally Posted by itsnotanova

Who's that in the picture with your car? I'm used to only seeing you covered up with grime and car gunk. You clean up good!

[itsnotanova]

I'm dirtier than I look. That's why I wear black a lot.

[itsnotanova]

I've had the 3.4 for a little while and it just doesn't feel as strong as it did in the 996. In the 996, the 3.4 felt stronger as the rpm's went up. In the 986, it feels flat until about 3000 rpm and really kicks in at 4000 rpm. The only thing different between the 986 and the 996 are the intake and exhaust system. The 987 air box and MAF I used are very similar in size to the 996, so I don't think that's the problem. I think my problem is the factory 986 exhaust system. It doesn't take too long looking at the 986 exhaust to realize how restrictive it is. I had already gone with aftermarket headers and a Dansk sausage muffler, but I still used factory secondary pipes. Here's a picture of pipes used on the 986 and 996. (Still not using gloves!)

The smaller one is the factory secondary pipe used on the 986 and it measures only 36mm. That leads into the U pipe at 42mm which then leads into the Dansk muffler that looks to go back down to 36mmish. The large pipe is used throughout the 996 exhaust system and it is 52mm. That's a big problem to me that the 3.4 in the 996 gets these huge pipes but the 986 has these little pea shooters. I'm thinking that my power loss is because of these tiny pipes that I'm using and that leads me to my experiment. I'm going to build my own exhaust using what I have laying around. In my arsenal of exhaust parts are 996, 987 and Audi S4B5 pieces. After a lot of cutting up exhaust parts and some thinking, I ended up with this. I've gone with 52mm pipe all the way back to a modified 987 muffler. I've also eliminated the secondary 986 cat pipe. You might ask why am I using the 987 muffler? First off it's free, and secondly it uses larger pipes inside it. I didn't get a chance to measure them but I would guess it uses somewhere around 50mm tubes inside it. My main goal is flow and I think the 987 muffler can handle the 3.4. I also like the sound of the 987 muffler and it has catalytic convertors built into it. I don't live in a county that test emissions, but it makes me feel a little better that they're there.
Here's a normal 987 muffler

And here's a little taste of mine. I've got it almost complete and will post pics when I'm done fabricating

[Porsche9]

Look forward to reading about the results!

[Smallblock454]

Hello woody.

2 videos from Motortrend / Freiburger for you:

The Power of 2.5- vs. 3-Inch Exhaust:
https://youtu.be/_PVXvHkr-Vs

Exhaust Header Bash! Testing Power Loss From Dents:
https://youtu.be/azPKIjxmmdU

OK, the engines can't be compared directly, but the result will be similar.

Please also note that the 2.5 exhaust system is different to the later 2.7/3.2 exhaust system.

On the last photo it looks like your system has only one exhaust pipe at the end. If that is like it looks i would say that's a design fault. Not because of optical aspects, but of technical aspects (overall diameter).

Very interested to hear about your final results.

Regards, Markus

[silver-S]

After watching that Motor Trend video and seeing your project, I predict you will sell all of your 987 s mufflers within a week or so after you do your testing. I'm watching this one closely!

[steved0x]

Maybe the larger 987 exhaust is part of the puzzle as to why the exact same engine in a 2005 Boxster S makes more HP than the exact same engine in a 2004 Boxster S. And why the 2004 Anniversary Edition 986 S splits the difference in HP (since it has the 987 airbox but not other pieces including the exhaust?)

2004 986 S: 258 HP
2004 Anniversary edition: 266 HP
2005 987 S: 276 HP

Since it is the same engine, I think (and I heard of someone doing this I think) they just took the whole exhaust of a Cayman, including the manifolds, and put in on their 986 Boxster.

[seningen]

Originally Posted by itsnotanova

From what I researched, there's not much you can do to make them come on at a lower temperature. Some guys are talking about having them hotwired and with a toggle switch so they can manually activate them. I'll probably just run my AC even when I don't need to for now. I would like having the option of running my heater and the fans on high when I want too though.

As for the paint. It's not too bad of a contrast and totally ok for most people. I'm a little picky when it comes to things like that. The rest of the car could use another coat of paint anyway. Especially the hood and front fenders because they have lots of rock chips on them

FYI -- I have the Under Drive Pulley -- when I go on track I turn off my AC
when I come off track -- I turn it back on -- to cool the engine as it kicks
the radiators on -- AND raise idle, increasing water pump circulation :-)

Mike

[steved0x]

Originally Posted by seningen

FYI -- I have the Under Drive Pulley -- when I go on track I turn off my AC
when I come off track -- I turn it back on -- to cool the engine as it kicks
the radiators on -- AND raise idle, increasing water pump circulation :-)

Mike

I do the same thing, turn on my AC when I start my cool down lap...

[itsnotanova]

In response to Markus,

I checked my supply and the exhaust manifold tubes are slightly bigger on the 00-04. The 97-99 exhaust manifold doesn't have the pre-cat's, so I'm guessing they might flow better. One of the best Porsche mechanic in Texas has a liking for the early 97 manifolds because he thinks they flow better. Some early 97's have a flat spot on them and that's how you can visually tell. On that note, I took a picture of the factory manifolds that I have. Starting from the left we have a 2005 987, early 97 flat manifold, 00-04 and a 2001 996 exhaust manifold. I didn't get around to measuring, but the 996 and 987 look close to the same size.

While I was at it, I took a picture of the secondary pipes from the 986 and 996. The 97-99 and the 00-04 are the same size and the only difference appears to be the lack of an O2 bung for the 00-04. It looks like they still kept the heat shield though.


From the research I came up with, the 987 base and S share the same muffler but have different tips that attach to one 70mm singular exit tube. I would have loved to have two separate tubes coming out of each muffler at a better angle. The factory muffler has the exhaust gases exiting towards each other and then making a 90 degree turn out. I'm thinking tomorrow I'll fabricate something to help the exiting gas flow better at that point.

My modified 987 muffler looks larger in this pic, but it's only a few inches wider than the 986 muffler. It's about the same total height in the middle but a few inches narrower on the sides

[itsnotanova]

Originally Posted by steved0x

Since it is the same engine, I think (and I heard of someone doing this I think) they just took the whole exhaust of a Cayman, including the manifolds, and put in on their 986 Boxster.

I looked to see if someone had done that but couldn't find any info. I'm thinking it's not possible. The 987 exhaust system and car are wider than the 986. I could be wrong though.

I'm too lazy to try and wire something up to manually control the fan at this time. I'll probably run my AC like you and Mike do. My only reasoning that I would like an override switch might be when you really need to cool an engine down fast. As in heater blowing and windows down. The car should have the fans going anyway, but I'd like to make sure.

[Smallblock454]

Hello woody,

thank you very much for the pictures and comparisons. BTW nice shoes.

What i was not aware of, when writing my last post, is that the US 986 00-04 headers have an additional catalysator. The ROW headers don't have that. They look more like the 97-99 header manifolds. The 97-99 exhaust system seems to have a different designed muffler system than the later cars.

I think it's pretty obvioius thet the 987 and 996 have a bigger diameter. In general the diameters in automotive industry are measured in inches (exterior diameter). So i would suspect from your measuring the 986 systems are a 1,5" (38,10 mm) system whereas the 987 / 996 systems seems to be 2" (50,08 mm).

If you can delete catalysators that is always a good idea to gain power. But you have adjust the ECU tuning, else there won't get a big benefit (in general stock catalysators are 400 cell catalysators).

What does the exhaust tip diameter has to be if have two 2" (50,08 mm) inlets? So one inlet has an area of 1970 mm2. Now we have to calculate that back for 2 inlets and get a diameter of 70,82 mm or 3940 mm2 for an optimal exhaust tip diameter. (Please note that all values are rounded.) So if the singular exit tube is 70 mm it's absolutely OK and correctly designed.

In my personal opinion 2 separated exhaust tips won't be a plus because of the x-pipe factor.

A before and after dyno run is always a plus.

Regards, Markus

[itsnotanova]

Made this today

and put it in here.

Now I'm waiting for the exhaust wrap and O2 fooler to come in the mail. I weighed the factory exhaust system from the headers back and my exhaust system is 13.5 lbs lighter.

[Smallblock454]

Hello woody,

couldn't see from your pictures exactly what you are doing, because some importatnt parts where too dark. So i adjusted the brightness a little bit. Hope that is OK.




13,5 lbs is a lot. Very interested how the final result comes out and if you're satisfied with that solution.

Regards, Markus

[itsnotanova]

Thanks Markus. I didn't notice how bad the pic was until I had already welded that piece in. I hate the camera on the IPhone5S. I had a phone ten years ago that took better pics. That piece I made is to help direct the exhaust gases out the tailpipe instead of facing each other. I cut two little pieces off some U pipe and welded them together. I then welded them to the back of the piece I cut out of the back.

[Sassmatt72]

So is it on the car yet?
Any thing you would do differently next time?
are you wraping or adding heat sheilds, it looks like you've moved it closer to the trans and cv joints?

installed pictures please.

thx for sharing.
matt

all because My ecu choice will not support 2 pair of O2 sensors. runs great tho, and sound is great, I can have a conversation or hear the radio at certain lower revs...

So this is how I plumbed my Subaru 2.5 NA SOHC 4 banger, the headder flange mates to OEM stock Boxster exhaust system....if I want to run stock or AF.

[Sassmatt72]

internal cleanup...

rear mounting...


the best part is the look on peoples faces when they hear a subaru burble (un-equal length y pipe) and see my "little" exhaust tip.

[itsnotanova]

I wish I had access to a mandrel tube bender and a tig welder. I'm using a mig and it's challenging trying not to burn through such thin metal. The tubes are made up from five different pieces and each joint is a weak spot for future cracking. I also wish I could done a better job with the exit pipe. Two separate pipes would flow better. I didn't have anymore 90 degree 52mm pipe so I stuck with the 987 section. I haven't got it installed yet because I'm waiting for exhaust wrap to show up in the mail. I live in a small town and none of the auto part stores had any in stock. Build thread?