Aftermarket "Performance" Cats: Worth the Trouble?

[sheward]

Sounds like you have a very good exhaust installer/fab./welder. Your description of the results are what i will be looking for in an exhaust change. I hope to have a set of headers made eventually for a complete system. The gains may not be substantial enough for a lot of owners to spend the money but this is a reverseable change that i like and when i finally get around to it i will use your post for reference. Would like to see some pics if you ever have the opportunity.

drew

 

[550Maranello]

No emissions in Florida!!!

 

[JordiC]

The state of Florida got rid of emissions testing years ago. Annual auto tag renewal costs just $58 and can be done online in a few minutes.

 

[Jelmer]

... wow. Didn't expect that. Was it California that's so strict, then?

 

[gsxr]

...Was it California that's so strict, then?

Yes. PRK (People's Republik of Kalifornia) is the absolute worst when it comes to emissions testing. The requirements vary in each city, some are worse than others. Oddly, diesel passenger cars are exempt, so there is a big advantage to owning a diesel in CA. My sister lives in CA and five of their six vehicles are diesel (three are W124 diesel, one W124 gas, and two diesel trucks).

 

[maw1124]

Yeah, I don't know what's up with YouTube (not my specialty -- my first ever upload). I couldn't even find it until I looked in my video manager. Is there some button I need to push or fee I need to pay? Try this:

http://www.youtube.com/watch?v=WUaiWYgX8xs
[youtube]WUaiWYgX8xs[/youtube]

My mechanic (who's taken care of the car for over 15 years, long before I had it) is in favor of the headers idea. The custom exhaust fabricator is in favor of some of these rear mounted exhaust driven turbo systems (new to me as of yesterday -- may give it a whirl on the M3). If you've seen them, the turbo goes where the back box used to live, and runs a feed all the way back to the engine (of course by then, it's cooled). I'm in favor of neither. I just consider this a car I cannot mod, beyond the RennTech mods it's had since the 90's (eProm and rear suspension). I consider this exhaust more of a fix than a mod -- driving it now convinces me it was at about 85% to 90% with the old cats AND the extra weight of the old system (easily 50lbs). I just couldn't see changing the cats which needed changing, and leaving the rest of that "vintage" stuff there -- didn't make any sense to me. So I did what I thought was sensible and put every piece back, just with better pieces. I should be able to get pix up no later than this weekend.

I know "Otto" (lawyer in Miami) was thinking about an exhaust as well. If you want a referral, PM me. SRQ is only 3hours from you and Alligator Alley is a fun drive in these cars.

Gents, thanks for the support.

Cheers,

maw

 

[Jelmer]

How good is this recording? What I really miss is the deep-growl. I like the fact it "speaks" more when revving, but it doesn't so much say "I'm a big V8, I'm strong, I don't need to prove myself", if you know what I mean. But, this might be the recording which lacks the proper lower-end undertone!

 

[2phast]

Yeah, I don't know what's up with YouTube (not my specialty -- my first ever upload). I couldn't even find it until I looked in my video manager. Is there some button I need to push or fee I need to pay? Try this:

http://www.youtube.com/watch?v=WUaiWYgX8xs
[youtube]WUaiWYgX8xs[/youtube]

My mechanic (who's taken care of the car for over 15 years, long before I had it) is in favor of the headers idea. The custom exhaust fabricator is in favor of some of these rear mounted exhaust driven turbo systems (new to me as of yesterday -- may give it a whirl on the M3). If you've seen them, the turbo goes where the back box used to live, and runs a feed all the way back to the engine (of course by then, it's cooled). I'm in favor of neither. I just consider this a car I cannot mod, beyond the RennTech mods it's had since the 90's (eProm and rear suspension). I consider this exhaust more of a fix than a mod -- driving it now convinces me it was at about 85% to 90% with the old cats AND the extra weight of the old system (easily 50lbs). I just couldn't see changing the cats which needed changing, and leaving the rest of that "vintage" stuff there -- didn't make any sense to me. So I did what I thought was sensible and put every piece back, just with better pieces. I should be able to get pix up no later than this weekend.

I know "Otto" (lawyer in Miami) was thinking about an exhaust as well. If you want a referral, PM me. SRQ is only 3hours from you and Alligator Alley is a fun drive in these cars.

Gents, thanks for the support.

Cheers,

maw

I did not find your video in a YouTube search either. I also saw it it has no "views" which might indicate its a private video vs. a public video. Check your video settings and make sure it is set for "public"

 

[maw1124]

How good is this recording? What I really miss is the deep-growl. I like the fact it "speaks" more when revving, but it doesn't so much say "I'm a big V8, I'm strong, I don't need to prove myself", if you know what I mean. But, this might be the recording which lacks the proper lower-end undertone!

You're dead on, Jelmer. My iPhone apparently cannot capture the octave that she's really speaking at. I'd guess it in the 40Hz to 60Hz range, maybe lower. If it's on a stereo, it's definitely coming from the sub. In person, it's clearly a "not for kids" growl if you know what I mean. Definitely deeper than the S55k or the Allroad, if you're familiar with those exhaust notes. I'll try again in the garage. And yes, 2PHAST, I'll check the YouTube settings.

maw

 

[maw1124]

Tried again. Capturing that sound on a phone is useless. Sorry Guys.

maw

 

[szvook]

I got your deep-growl v8 right here, my 500E with an RB Tech cat-back exhaust: all stainless steel dual exhaust, mandrel bent 3 inch pipes, X-pipe and two custom mufflers.

[video=youtube;Hwid2vRMxTc]http://www.youtube.com/watch?v=Hwid2vRMxTc[/video]

 

[maw1124]

I got your deep-growl v8 right here, my 500E with an RB Tech cat-back exhaust: all stainless steel dual exhaust, mandrel bent 3 inch pipes, X-pipe and two custom mufflers.

[video=youtube;Hwid2vRMxTc]http://www.youtube.com/watch?v=Hwid2vRMxTc[/video]

I bet your real sound is deeper. That "silence" after start up is the notes these phones cannot catch. But we beat that horse to death.

On a more technical note, why 3" pipe as opposed to 2.5"? I read the Vinard stuff (of course), and talking with my guy today (who's WAY into the science and technicality of this, which surprised me), he told me each of my mufflers flow over 500 whatever the measurement unit is (I forget), whereas according to the Vinard formula, only 770-800 "flow units" are necessary to make it a zero restriction system. I think Christian K is the expert on this. Anyone want to weigh in on 2.5" vs. 3" and its effect on performance or sound? Also, anyone want to weigh in on the "quality of pipe" issue, which I understand is important to performance, sound, durability AND ease of welding (easier to weld through the thinner pipe)? Thoughts?

maw

 

[szvook]

I bet your real sound is deeper. That "silence" after start up is the notes these phones cannot catch.

It does sound deeper than what’s on the recording. You need to hear it away from the iPhone, speakers with a sub or headphones with at least 50mm drivers will do the job.

On a more technical note, why 3" pipe as opposed to 2.5"?

Better flow, less restriction, deeper note and a bit of added HP; (but that's mostly because of the X-pipe).

 

[gsxr]

My mechanic (who's taken care of the car for over 15 years, long before I had it) is in favor of the headers idea.

Headers look very cool but there is an awful lot of evidence indicating they are not a magic bullet to increase power on the M119. IMO, there may be a bigger potential for power gain via porting/polishing the intake manifold & head, and port matching. I've been wanting to try this sometime and might actually do it when I replace the head gaskets on my E500. I've already got "before" dyno graphs, so after the intake mods I could go back to the dyno and see what happened, if anything.

The custom exhaust fabricator is in favor of some of these rear mounted exhaust driven turbo systems (new to me as of yesterday -- may give it a whirl on the M3). If you've seen them, the turbo goes where the back box used to live, and runs a feed all the way back to the engine (of course by then, it's cooled).

There is potential for serious power gains here, but it may require going to standalone engine management, like the Mongillo SL500 used to get 416rwhp (est. 500hp at the crank). Not cheap or easy, and there are drawbacks, but it's a massive power increase.

I'm in favor of neither. I just consider this a car I cannot mod, beyond the RennTech mods it's had since the 90's...

That would be the most wallet-friendly option for sure! I think it sounds great as-is. I'd also leave the tips as they are now... you can't un-cut the bumper later, so it would be $1k+ if you ever wanted to undo that mod. I have the Remus box on my E500 and it hangs just under the bumper like yours. Doesn't bother me a bit. You could also go with a stealth exit like I think 2phast and Gerry did on their cars. (?)

 

[maw1124]

Right. As soon as he mentioned the computer in the turbo mod, I was like, "Oh no, we're gonna leave the computers happy." Keep me posted on the headers, please. Thanks for the advice and compliments, Dave. I think the bumper is a done deal, though. I recognize it will mean a new bumper if I don't like it. But oh well. Risk aversion never helped me get anywhere. I'll update the board when it's done. Also, on how the exhaust feels, sounds, etc. after a couple of long trips. I have a SRQ to ATL run coming up (likely), then a SRQ to N'Awlens run -- I'm wondering if there's a settling in period...

Cheers,

maw

 

[gerryvz]

Damned impressive butt dyno results from maw1124 !!

 

[maw1124]

Damned impressive butt dyno results from maw1124 !!

Funny thing, Gerry, is I'm thinking the RennTech eProm may never have actually made it into my car. Last year around this time, I had to replace my LH Module to fix a cold start problem. You guys may remember that. Well today, my mechanic says to me, "Oh, bring that module back. I didn't know your car had the RennTech eprom until you told me (last month). If that chip is in the old unit, I need to get it out and into the new unit, now that you've done the exhaust work." Well, long story short is, from my records on the car, I can tell a prior owner purchased the chip and that RennTech sent it to him. I cannot tell when it was installed. So I go in the attic looking for the old LH module -- no luck. I don't think I actually got it back from them when they put the new one in. But I look in the canvass bag in the trunk that the old owner gave me -- the one that contains my 500E badge, among other things -- and I see a container with "MBZ Headlight and Chip" written on it in black sharpie. You know what I'm thinking. We'll see tomorrow.

Anyway, I digress. Sorry it took these pix so long to upload. Doing it from my Macbook wouldn't work (the Mac and the site wouldn't play well together), so I sent them to a non-Mac computer and it worked flawlessly. Nothing groundbreaking here, but I said I would upload them and I think it's important to keep my word. So here they are...

Happy trails, Gents. I'll update on the eprom if that "chip" is what I think it is.

maw

 

[gsxr]

Interesting. Make sure the EPROM is correct for the LH module. If you put a late (93-up) EPROM into an early (1992) module, you'll get a power loss.

 

[maw1124]

Interesting. Make sure the EPROM is correct for the LH module. If you put a late (93-up) EPROM into an early (1992) module, you'll get a power loss.

Well, I may be hosed. I hope they still have that old module at the shop, because the chip that's in my trunk is the stock chip. I checked the part number. I doubt RennTech gave the prior owner the wrong chip. But your warning will prove helpful if I have to go back to RennTech for another chip (hoping they have old stock). Right, I know. Like I said, I may be hosed.

Thanks Dave. By the way, I took your advice, left the exhaust tips the way they were, and didn't cut the bumper. I'm gonna call that project done. As you can see, I'm off to the next one. Any thoughts on chips for this car besides RennTech?

;-D

maw

 

[gsxr]

The exhaust looks nice! I'm guessing it sounds pretty sweet too, eh?

About the chip. Someone was kind enough to send me what was allegedly a RENNtech chip of the 1993-94 variety. After examining the code, I found the only difference was they removed the top speed limiter. Nothing else. Nada. Zip. Zilch. Now, I could not prove it was a genuine/original RENNtech chip, but I wouldn't be surprised if it were. There is basically no power to be gained via chips. However you do get the top speed limit removal and (on some chips) elimination of the cold upshift delay. In a nutshell, I'd spend the money elsewhere.

 

[maw1124]

The exhaust looks nice! I'm guessing it sounds pretty sweet too, eh?

About the chip. Someone was kind enough to send me what was allegedly a RENNtech chip of the 1993-94 variety. After examining the code, I found the only difference was they removed the top speed limiter. Nothing else. Nada. Zip. Zilch. Now, I could not prove it was a genuine/original RENNtech chip, but I wouldn't be surprised if it were. There is basically no power to be gained via chips. However you do get the top speed limit removal and (on some chips) elimination of the cold upshift delay. In a nutshell, I'd spend the money elsewhere.

Fair enough. I think you're right. If I can't find my old module, and RennTech won't "comp" me another chip, the only other thing I'm thinking about is having someone reprogram this "extra" stock chip. All of those are low money fixes. I don't see myself spending any real quid on this one. I'm happy with the car. Much more responsive with the new exhaust, and the sound just makes it more fun to drive. I can better hear her "holding her notes." Good stuff all around.

Cheers,

maw

 

[Jelmer]

Looks good, maw, but you seem to have posted thumbnails (i.e., I can't click to enlarge)... Fancy trying again? If you can't, don't want to or don't have the time, feel free to mail them to me (PM me for my address).

 

[gsxr]

Back on topic:

 

[szvook]

Cat-back fever....

 

[maw1124]

The exhaust looks nice! I'm guessing it sounds pretty sweet too, eh?

About the chip. Someone was kind enough to send me what was allegedly a RENNtech chip of the 1993-94 variety. After examining the code, I found the only difference was they removed the top speed limiter. Nothing else. Nada. Zip. Zilch. Now, I could not prove it was a genuine/original RENNtech chip, but I wouldn't be surprised if it were. There is basically no power to be gained via chips. However you do get the top speed limit removal and (on some chips) elimination of the cold upshift delay. In a nutshell, I'd spend the money elsewhere.

At the risk of thread jacking... When my mechanics recently moved to a new shop, (drum roll please), the found my old engine module, the one with the RennTech chip in it. So when the car was in for service, I had them re-install it. This time, with a "new and improved" exhaust -- featuring the Magnaflow performance cats (which I consider worth the money). Initial impressions? I concur with Dave -- "Nada. Zip. Zilch." I can't tell any difference. Maybe, just maybe, the redline is higher and she's running richer (seems a little jumpier, like hopped up on fuel). But I can't confirm that. She's still way too fast to be this old. But as far as chip and exhaust tuning, I think high flow cats and less weight is all there is to be had here, presuming you have the WOT enrichment in the first place.

Cheers, Gents.

maw

 

[M104-AMG]

FWIW, the difference between a 49-state and a California CARB-approved cat is in the volume of much catalytic-converter precious metals (usually platinum) CARB cats have to work better and longer.

A friends Honda was throwing CHECK ENGINE lights continuously even with a new CAT installed. I ditched out the cat, for a CARB approved cat from Magnaflow, and no problems/CHECK ENGINE for over 3-years.

Magnaflow CARB-approved cats for 500E: 332204, 332005, 332006

neil

 

[clarkz71]

Found those cats, ship from Australia

http://www.ebay.com/itm/MAGNAFLOW-2-5-INCH-100-CELL-CPSI-METAL-CAT-CONVERTER-/360383613994

 

[M104-AMG]

Found those cats, ship from Australia

http://www.ebay.com/itm/MAGNAFLOW-2-5-INCH-100-CELL-CPSI-METAL-CAT-CONVERTER-/360383613994

Ebay says: May not ship to United States.

:-( neil

 

[maw1124]

A couple of notes from the experience: (a) I may re-do the tips, and simply cut the rear bumper for a more stealthy look. That may mean a re-do on the back box. So if you like an OEM look, consider doing that the first time; (b) I liked having all the components there -- resonator delete was too loud for me. My exhaust fabricator let me "sound test" different fitments, which was helpful.

Final update here from me. I ended up getting rid of the tips for a more stealthy look, but didn't cut the bumper (thanks, GSXR for that advice). I just went straight out the muffler with an angle cut to match the angle of the bumper.

Pics attached (again, need admin help).

Cheers,

maw

 

[M104-AMG]

California CAT for '93 500E, Magnaflow 3322305

MSRP $762 each.

neil

MagnaFlow California Grade CARB Compliant Universal Catalytic Converte

Keep the check engine light off with MagnaFlow California Grade CARB Compliant Universal Catalytic Converter 3322305. The Universal design allows the part to fit a wide array of vehicles (cutting and welding required), and the stainless steel construction of this spun body catalytic converter is...

www.magnaflow.com