Exhaust and tunning

[Qckslvr]

So I have done my searching and nothing really answers the questions I have.

So first off I am looking to unleash the natural boxer sound of my Boxster. As we all know the stock exhaust hides a lot of the cars sound. I would like to car to sound like a Porsche, a sports car. BTW my car is a 2001 Boxster S

I am no stranger to exhaust systems, or tuning for that matter. But! My budget is a little more limited this time around. ( I still have power window that is frustrating the hell out of me)

So here my thoughts. I have looked at both the Fabspeed Maxflow system and the Borla system. I have also looked at the Soul Performance vacuum controlled exhaust cutouts.

So first thought.... Ebay headers with the Fabspeed Maxlow system.

Second though... Ebay headers with Fabspeed secondary cat delete with Borla Exhaust

Third thought... Ebay headers with Fabspeed secondary cat delete with Soul Cut Outs and the stock muffler

Now my questions.... With the main converters removed will I throw a CEL?

Next.... I noticed the Fabspeed Maxflow and even there other systems have a pipe between the tips for exhaust equalization. I know from the Mustangs I have had that an H or X Pipe one changes exhaust notes, but mostly helps with the equalization of exhaust pressures, and helps scavenging. The Borla does not have this tube. Does the Boxster or boxer engine for that matter suffer performance issues because of this?

Last.... Assuming I will not throw a CEL with headers, etc.... is a tunner needed? I wish I could use the tunner from my Mustang, but I doubt American tuners talk to German cars...

Thank you for your insight

[Geof3]

I’ve got headers and cat delete but running a stock muffler (came that way when I bought it). Based on a decent amount of feedback, the Fabspeeds sound great, but have a significant drone. A cross pipe helps with that. When the time comes I will be doing the FVD Brombacher Sound version muffler. The reviews I’ve read are stellar and the pricing is very nice. Regarding which headers are best? I’m sure others can help with that. One thing to note with headers, you loose all of your heat shielding, thus your power steering line needs to be wrapped in thermal tape of some sort.

[j.fro]

The eBay headers are a great start. I had your "second thought" setup for a while. With no cats, you will definitely get a cel unless you also get the ecu tuned. This setup is really loud, over 98 dB at WOT. The SCCA hit me with a sound meter and threatened to ban me from AXevents if I didn't quiet it down. I welded in 100 cell cats and it did the trick. The Borla muffler is not the sturdiest piece. More than once I had to reweld the bracket that mounts to the trans. Oh, lots of drone in the 2500-3000 range. But it sounds like a cup car and everybody loves it, except for SCCA officials.

[truegearhead]

Originally Posted by j.fro

The eBay headers are a great start. I had your "second thought" setup for a while. With no cats, you will definitely get a cel unless you also get the ecu tuned. This setup is really loud, over 98 dB at WOT. The SCCA hit me with a sound meter and threatened to ban me from AXevents if I didn't quiet it down. I welded in 100 cell cats and it did the trick. The Borla muffler is not the sturdiest piece. More than once I had to reweld the bracket that mounts to the trans. Oh, lots of drone in the 2500-3000 range. But it sounds like a cup car and everybody loves it, except for SCCA officials.

J.Fro is right no cats is too loud for the street. Here’s some other thoughts

1. If you change the headers you will more than likely break a bolt off in the head and that is a nightmare. I broke three off and towed it to a machine shop

2. The exhaust is absurdly heavy and blocks access to working in the car. So it’s great swap in those regards but it won’t really make any audible difference. (At least with the few I’ve heard)

3. Hi-flo cats will give you the biggest performance gain and will also make the car louder

4. With a louder exhaust you will no longer be able to hear that great intake noise that boxsters have.

[Dave80GTSi]

Opinions on this topic are like belly buttons - everybody has one.

So, since you are asking, here's mine:

1) The cheap Chinese eBay headers seem to be a mixed bag. Some folks love them and have no problems, while others have all sorts of frustrating fitment problems with them. How lucky do you feel today?

I have wasted far too many hours of my life trying to fit aftermarket headers to many other cars which never seem to fit "just right". So for me, the Chinese eBay headers were never even a consideration.

Since the biggest performance gain to be had by deleting the OEM cat manifolds is due to getting rid of their flow restricting cats, I instead went a different path.

I would recommend that you read the text, especially concerning the mini-cats, that I have posted in this ad:

For Sale: Hollowed OEM Exhaust Manifolds, Complete with Mini-Cats

Considering the modest cost, I would objectively recommend that you go this route, as you will be assured of -zero- fitment problems, while also gaining a significant reduction in heat at this area of the engine.

2) "While you are there", replace the manifold bolts which go into the head with M6 studs and nuts. The next time that you twiddle in this area of the engine, you will be glad that you did:



3) The aftermarket secondary pipes that are out there, once again, anecdotally vary in their fit and quality. If all that you are trying to do is to remove restrictions, then why not simply remove the cats from your existing OEM pipes? Just Dremel off the end cap, remove the cat canister, and then reweld the canister closed. As before, you are guaranteed of a correct fit via the use of OEM parts, and the cost is nothing if you know a guy who has a welder:



4) At this point, you have free flowing manifolds and secondary pipes, all done for almost no money. Before you would go to the final step of replacing the OEM muffler, live with the above improvements for a bit and see how you like them. I would be willing to bet that this gets you where you wish to be. But if not, then one muffler that I really like is the so-called Dansk "sausage". Much more compact than OEM, and it sounds great without droning:



(I bought mine used; dents shown are courtesy of previous owner).

So, there you are. By thinking this one thru and not blindly buying aftermarket parts, I suspect that you will find your own personal nirvana.

Thanks - DM

[The Radium King]

just get the full-meal chinese deal (fabspeed knock-off) - headers, mid-pipes, muffler, and put it on. it is cheap. if headers don't fit you can buy another set and still be ahead of a fabspeed setup. if too loud then put your oem muffler back on. if there is drone, look to improving the clamps used.

your car needs the second set of o2 sensors for emissions purposes. not sure what you have for emissions testing where you are, however solutions to removing your cats (with varying success) are:

- have a shop push the 'rest of world' (row) tune onto your car. this is not a performance tune, just the ecu map porsche uses for cars outside of north america. it will not throw a cel for missing emissions equipment. if the dealer has the proper porsche computer to do the work it'll take all of 10 minutes of shop time. you'll need the programming codes for your car to do this.
- get a cheater. some people use a spark plug extender socket. the idea is to get the sensor out of the direct stream of the exhaust so that the computer thinks the cats are there and working. the really expensive cheaters have little cats in them.
- just tuck the sensors up under the car. they will read fresh air and think the cats are working.

[Qckslvr]

I too have had varying success with headers. Hooker headers for a 390 that took 2 hours of grinding, heat, and massaging to make fit a Mustang. Or OBX turbo header that crack midway through a race on a Miata.

So yes I am skeptical.

I live in CA, home of the smog demons CARB.

I am not opposed to changing the system back to stock every two years. So the tip on changing the bolts to studs, is greatly appreciated. I shall check into ARP.

I am looking for improved performance, and saving my very expensive cats from future replacement.

[Dave80GTSi]

Originally Posted by Qckslvr

I too have had varying success with headers. Hooker headers for a 390 that took 2 hours of grinding, heat, and massaging to make fit a Mustang. Or OBX turbo header that crack midway through a race on a Miata.

So yes I am skeptical.

I live in CA, home of the smog demons CARB.

I am not opposed to changing the system back to stock every two years. So the tip on changing the bolts to studs, is greatly appreciated. I shall check into ARP.

I am looking for improved performance, and saving my very expensive cats from future replacement.

Oh, don't get me started on aftermarket header fitment issues! Seems like we've both been there many times before!

ARP studs? Should not need to go to all that much trouble. You do not need super strength steel studs as you are threading into an aluminum head, and those threads are the weakest link. Simply go to your local Lowe's Depot and buy a dozen M6 bolts in the longest thread length that they have, and then Dremel off the heads. Voila: Studs!

(See PM sent)

Thanks - DM

[The Radium King]

if going oem, realise that the exhaust manifold tubes are not equal length, and the flow merging leaves a lot to be desired. further, gutting the cats creates an area where the flow expands and then contracts again, using energy and potentially causing exhaust gas pulses.

note also that this is a tuned system and efforts to achieve max hp (improving flow) may actually impede torque at lower rpms; if this is a concern then oem is a good choice.

if you are looking for max hp, try to put any restrictions as far downstream as possible. at the muffler if you can. if you need to have emissions then keep the secondary cats on the mid-pipes and extend your o2 sensors to downstream of these. as others have noted, first step is the headers - you can go cheap and take a risk (the cheap chinese stuff is obx, and a number of other resellers) or pay bigger money for better product. with ebay and paypal, warranty protection is pretty good on this stuff these days, however.

finally, as also previously stated, regardless of the route you go, you will probably see more of a performance increase from the weight reduction (10 lbs = 1 hp give or take) than from any improvements to exhaust gas flow.

[Anker]

Why not just weld a set of bypass pipes to your existing stock muffler. By far the least expensive option, no drone and the same sound you would get with the factory sports exhaust option.

[tommy583]

Or better yet do the internal exhaust bypass mod. Works like a charm, sounds great and is almost free.

[mikefocke]

Given where you live, listen to people who have passed CA's smog tests.

[Geof3]

Originally Posted by Dave80GTSi

Opinions on this topic are like belly buttons - everybody has one.

So, since you are asking, here's mine:

1) The cheap Chinese eBay headers seem to be a mixed bag. Some folks love them and have no problems, while others have all sorts of frustrating fitment problems with them. How lucky do you feel today?

I have wasted far too many hours of my life trying to fit aftermarket headers to many other cars which never seem to fit "just right". So for me, the Chinese eBay headers were never even a consideration.

Since the biggest performance gain to be had by deleting the OEM cat manifolds is due to getting rid of their flow restricting cats, I instead went a different path.

I would recommend that you read the text, especially concerning the mini-cats, that I have posted in this ad:

For Sale: Hollowed OEM Exhaust Manifolds, Complete with Mini-Cats

Considering the modest cost, I would objectively recommend that you go this route, as you will be assured of -zero- fitment problems, while also gaining a significant reduction in heat at this area of the engine.

2) "While you are there", replace the manifold bolts which go into the head with M6 studs and nuts. The next time that you twiddle in this area of the engine, you will be glad that you did:



3) The aftermarket secondary pipes that are out there, once again, anecdotally vary in their fit and quality. If all that you are trying to do is to remove restrictions, then why not simply remove the cats from your existing OEM pipes? Just Dremel off the end cap, remove the cat canister, and then reweld the canister closed. As before, you are guaranteed of a correct fit via the use of OEM parts, and the cost is nothing if you know a guy who has a welder:



4) At this point, you have free flowing manifolds and secondary pipes, all done for almost no money. Before you would go to the final step of replacing the OEM muffler, live with the above improvements for a bit and see how you like them. I would be willing to bet that this gets you where you wish to be. But if not, then one muffler that I really like is the so-called Dansk "sausage". Much more compact than OEM, and it sounds great without droning:



(I bought mine used; dents shown are courtesy of previous owner).

So, there you are. By thinking this one thru and not blindly buying aftermarket parts, I suspect that you will find your own personal nirvana.

Thanks - DM

Any significant weight savings with the Dansk muffler?

[Dave80GTSi]

Originally Posted by Geof3

Any significant weight savings with the Dansk muffler?

My OEM muffler weighs roughly 35 pounds.

My Dansk muffler weighs roughly 27 pounds.

[Qckslvr]

So after listening to some more sound clips and reviews of the FVD Brombacher Sound Version, I ordered one. Along with a used set of headers and test pipes.

Now the last set of questions I have.

Should I use a traditional header gasket or the OEM stamped metal gasket. I know from experience that early Fords would crack their manifolds or damage the head if you used a header gasket. It prevented proper heat transfer from the manifold to the head.

Also should I wrap the headers and the test tubes with header wrap? Good or bad idea?

I am keeping my fingers crossed that no bolts decided to break on removal. I am skilled at bolt removal.... but what a pain.

Also are the exhaust manifold bolts/studs 6mm or 8mm? Dave mentions 6mm, but other sites say 8mm. I would like to be prepared for my project.

[rfuerst911sc]

I was lucky my eBay Chinese headers fit fine and all bolts came out . When installing exhaust hardware either add some copper based anti seize or an old trick is Milk of Magnesia on the threads . I am told many military aircraft have M of M on thousands of bolts with no issues removing them in the future .

[Dave80GTSi]

Originally Posted by Qckslvr

Also are the exhaust manifold bolts/studs 6mm or 8mm? Dave mentions 6mm, but other sites say 8mm. I would like to be prepared for my project.

Oops, upon further reflection, I do believe these to be M8. Good catch!

Nevertheless, wise for to remove one and to measure it first to confirm, before you buy replacements.

You should be OK to reuse your OEM thin metal manifold-to-head gasket.

Thanks - DM

[Geof3]

Originally Posted by Qckslvr

So after listening to some more sound clips and reviews of the FVD Brombacher Sound Version, I ordered one. Along with a used set of headers and test pipes.

Now the last set of questions I have.

Also should I wrap the headers and the test tubes with header wrap? Good or bad idea?

Bad. The M96 is somewhat notorious for spark plug tube leaks, and even cam cover leaks to some degree. That oil will pretty much drip right on top of a header pipe potentially, coating the wrap in oil over time. I was going to wrap mine until I researched it and saw a few videos of fires from just this sort of thing. Definitely need to wrap your PS line though, a burn through of that is a major fire hazard. Also helps keep an already hot PS system a little cooler to avoid spill over from your PS res.

[lowpue]

Originally Posted by tommy583

Or better yet do the internal exhaust bypass mod. Works like a charm, sounds great and is almost free.

where can I get info on this mode....is there a link

[PaulE]

Originally Posted by lowpue

where can I get info on this mode....is there a link

I think this is what you're looking for. There is also a modification called the Crios Modification which I think involves adding cutout pipes to your muffler.