Cats - how restrictive are they?
08-21-2007, 02:38 PM
#26
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You gain HP and save alot of weight eliminating the stck system and upgrading with a tuned exh system. You need two people to carry that stck exh system around also as opposed to one person being able to move the aftermarket system around.
Frank I noticed a very dramatic difference in hp just by replacing the secondary cats back. You're not gonna believe anyone unless you do it.
Last edited by ProjectC55; 08-21-2007 at 02:40 PM.
08-21-2007, 02:40 PM
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grocery getter
Try Magnaflow / Carsound's 599 line. Best flowing metal cat on the market today.....
http://www.eadperformance.com/catalo...d5d6d6a2beddda
http://www.eadperformance.com/catalo...d5d6d6a2beddda
08-21-2007, 02:43 PM
#28
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Try Magnaflow / Carsound's 599 line. Best flowing metal cat on the market today.....
http://www.eadperformance.com/catalo...d5d6d6a2beddda
http://www.eadperformance.com/catalo...d5d6d6a2beddda
08-21-2007, 03:16 PM
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E55
Try Magnaflow / Carsound's 599 line. Best flowing metal cat on the market today.....
http://www.eadperformance.com/catalo...d5d6d6a2beddda
http://www.eadperformance.com/catalo...d5d6d6a2beddda
08-21-2007, 03:20 PM
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Albert I dissagree and you can ask PTE,myself,Chiromikey ,Vrus and others. Did'nt you buy vrus's system? I only did not agree with the H pipe Vrus uses which is inferior to an X-pipe setup which makes a world of a difference as well.
You gain HP and save alot of weight eliminating the stck system and upgrading with a tuned exh system. You need two people to carry that stck exh system around also as opposed to one person being able to move the aftermarket system around.
Frank I noticed a very dramatic difference in hp just by replacing the secondary cats back. You're not gonna believe anyone unless you do it.
You gain HP and save alot of weight eliminating the stck system and upgrading with a tuned exh system. You need two people to carry that stck exh system around also as opposed to one person being able to move the aftermarket system around.
Frank I noticed a very dramatic difference in hp just by replacing the secondary cats back. You're not gonna believe anyone unless you do it.
08-21-2007, 03:25 PM
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I agree on a N/A car, however I think a supercharged car needs back pressure. From what I remember, I think VRUS car lost hp with his new exhaust set-up. I might keep my secondary cats and the resonator and simply eliminate the primary cats. I think this will give the biggest impact over stock exhaust. I have seen some board members complain about loss of tq and hp from also removing secondary cats. A racing secondary cat might hurt as opposed to help if that were the case. How much does the stock exhaust weigh? Chiromikey did you weigh your stock exhaust vs your new exhaust?
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
08-21-2007, 03:29 PM
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08-21-2007, 04:32 PM
#34
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Albert I dissagree and you can ask PTE,myself,Chiromikey ,Vrus and others. Did'nt you buy vrus's system? I only did not agree with the H pipe Vrus uses which is inferior to an X-pipe setup which makes a world of a difference as well.
You gain HP and save alot of weight eliminating the stck system and upgrading with a tuned exh system. You need two people to carry that stck exh system around also as opposed to one person being able to move the aftermarket system around.
Frank I noticed a very dramatic difference in hp just by replacing the secondary cats back. You're not gonna believe anyone unless you do it.
You gain HP and save alot of weight eliminating the stck system and upgrading with a tuned exh system. You need two people to carry that stck exh system around also as opposed to one person being able to move the aftermarket system around.
Frank I noticed a very dramatic difference in hp just by replacing the secondary cats back. You're not gonna believe anyone unless you do it.
Weight savings is one thing but a hp increase will be very small, with either an X-pipe or an H-pipe imho. I believe the bottleneck is from the exhaust valve on the cylinder head.
08-21-2007, 04:55 PM
#35
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Would there be any meaningful gains and how much to an N/A engine like my SLK 55 if I were to replace both sets of cats with race cats or remove primary and replace secondaries and add an xpipe in place of the resonator? I'd like some extra umph from the SLK but I don't want to go crazy such as a blower. It's jumpy enough as it is. Cats and xpipe are fairly cheap if they're worth the ponies. I imagine weight savings would be good to. I still have the stock 'headers', can't convince myself to spend $5k on replacements for what is only a few hundred dollars worth of metal.
08-21-2007, 06:50 PM
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08-21-2007, 06:59 PM
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Can you let me know who built that again. I was talking to them about doing the sl manifolds but wasnt sure if they new how much work it would be. I also wonder if they make the headers, exhaust all out of titanium if that would shave alot of weight? We could just use the factory mufflers?
08-21-2007, 08:44 PM
#38
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Nope, I have a factory exhaust minus the primary cats and the beginning portion of the exhaust due to my headers being like the kleeman.
Weight savings is one thing but a hp increase will be very small, with either an X-pipe or an H-pipe imho. I believe the bottleneck is from the exhaust valve on the cylinder head.
Weight savings is one thing but a hp increase will be very small, with either an X-pipe or an H-pipe imho. I believe the bottleneck is from the exhaust valve on the cylinder head.
x-pipe wrks way better than an H-pipe read:
old post:
vic i'm surprised you went with an H-pipe setup vs an X-pipe setup in your system. Here's a good read on why I think the x-pipe is better:
http://www.carcraft.com/techarticles..._installation/
http://www.carcraft.com/techarticles.../photo_10.html
Good pics and HP #'s
H-Pipe, X-Pipe, 1, 2, 3...
An Exhaust System Based On A Universal X-Pipe Crossover And A Pair Of Stainless Steel Street Series Mufflers
By Matthew King
Photography: Matthew King
Do you really need an exhaust system on your car? That’s a good question. If you have neighbors, drive it on public streets anywhere there are cops, or race it on virtually any NHRA track in the country, the answer is probably yes. Will it cost you power compared to open headers? Although that answer is also frequently yes, it can be no with the right system.
We’ve been running open headers on our ’86 Mustang project car since day one because it was the easiest thing to do and it seemed cool. It was also brutally loud, but it did pass muster at our local track because Los Angeles County Raceway doesn’t enforce a 95-decibel rule or require mufflers like many “street-legal” drag programs do. However, we always wondered if the open headers were costing us a little low-end torque due to a lack of backpressure. To find the answer, we took the car to Magnaflow Performance Exhaust’s research and development center. After discussing our combination and the way the car is used (100 percent at the track), Magnaflow built a system based on its universal X-pipe crossover and a pair of its stainless steel street series mufflers.
For any performance exhaust system, some type of crossover connecting the two sides of a dual exhaust system is important because it acts to balance the two banks of the engine. The common H-style crossover is good at balancing sound pulses between the two halves, but does little to promote scavenging because the exhaust gases tend to follow the path of least resistance, which is straight through each pipe rather than taking the 90-degree turn through the H-pipe into the other half of the system. In an X-pipe system, however, where the two sides of the system intersect, the gasses have no choice but to intermingle as they pass through the junction. This promotes improved scavenging effects by smoothing out uneven exhaust pulses from the engine’s firing order. It also helps quiet down the exhaust, resulting in a mellower, less raspy tone. According to Magnaflow, the faster acceleration of the gasses through an X-pipe causes them to flow in a linear fashion parallel to the walls of the tubing rather than tumbling. This “laminar” flowing gas is much quieter than tumbling gas, resulting in an exhaust tone up to 8 decibels quieter than a traditional H-pipe.
We left the car at Magnaflow for about a week, and when we came back we found that after some preliminary testing, the guys had built a really trick system consisting of 2-½-inch tubing from the header collectors into the X-pipe, 3-inch out of the X flaring into 3½-inch tubing running for about 26 inches before necking back down into a pair of 3-inch mufflers with turn-downs. The theory behind this design is that it will keep the velocity of the exhaust gases moving quickly through the headers into the X-pipe to maximize the scavenging effect, while the larger-diameter tubing ahead of the mufflers prevents the gasses from stacking up as they pass through the mufflers to avoid excessive backpressure in the system.
Sounds good, but would it work? To find out, we tested three exhaust-system configurations on Magnaflow’s in-house Dynojet. For a baseline, we ran the car with open headers and saw 333 hp at 6,300 rpm and 304 lb-ft of torque at 5,200 at the rear wheels. Next, we ran a 2-½-inch bolt-together system consisting of a BBK short off-road H-pipe designed to fit the company’s full-length headers connected to a set of race-type 2-½-inch welded mufflers with turndowns. Our Mustang’s carbureted 302 didn’t like this combo, as power fell to 323 hp at 6,300 rpm and 295 lb-ft of torque at 5,200. The increased backpressure also richened up the air/fuel mixture by about two carburetor jet sizes.
Finally, we swapped on the stepped X-pipe setup and were impressed to see power levels equal to the open headers: 335 hp at 6,300 hp and 302 lb-ft at 5,200. That’s a gain of 12 rear-wheel horsepower, although it turns out we weren’t really giving anything up or gaining anything extra from the open headers. So the car’s happy, and our ears are even happier!
http://www.carcraft.com/techarticles..._installation/
http://www.carcraft.com/techarticles.../photo_10.html
Good pics and HP #'s
H-Pipe, X-Pipe, 1, 2, 3...
An Exhaust System Based On A Universal X-Pipe Crossover And A Pair Of Stainless Steel Street Series Mufflers
By Matthew King
Photography: Matthew King
Do you really need an exhaust system on your car? That’s a good question. If you have neighbors, drive it on public streets anywhere there are cops, or race it on virtually any NHRA track in the country, the answer is probably yes. Will it cost you power compared to open headers? Although that answer is also frequently yes, it can be no with the right system.
We’ve been running open headers on our ’86 Mustang project car since day one because it was the easiest thing to do and it seemed cool. It was also brutally loud, but it did pass muster at our local track because Los Angeles County Raceway doesn’t enforce a 95-decibel rule or require mufflers like many “street-legal” drag programs do. However, we always wondered if the open headers were costing us a little low-end torque due to a lack of backpressure. To find the answer, we took the car to Magnaflow Performance Exhaust’s research and development center. After discussing our combination and the way the car is used (100 percent at the track), Magnaflow built a system based on its universal X-pipe crossover and a pair of its stainless steel street series mufflers.
For any performance exhaust system, some type of crossover connecting the two sides of a dual exhaust system is important because it acts to balance the two banks of the engine. The common H-style crossover is good at balancing sound pulses between the two halves, but does little to promote scavenging because the exhaust gases tend to follow the path of least resistance, which is straight through each pipe rather than taking the 90-degree turn through the H-pipe into the other half of the system. In an X-pipe system, however, where the two sides of the system intersect, the gasses have no choice but to intermingle as they pass through the junction. This promotes improved scavenging effects by smoothing out uneven exhaust pulses from the engine’s firing order. It also helps quiet down the exhaust, resulting in a mellower, less raspy tone. According to Magnaflow, the faster acceleration of the gasses through an X-pipe causes them to flow in a linear fashion parallel to the walls of the tubing rather than tumbling. This “laminar” flowing gas is much quieter than tumbling gas, resulting in an exhaust tone up to 8 decibels quieter than a traditional H-pipe.
We left the car at Magnaflow for about a week, and when we came back we found that after some preliminary testing, the guys had built a really trick system consisting of 2-½-inch tubing from the header collectors into the X-pipe, 3-inch out of the X flaring into 3½-inch tubing running for about 26 inches before necking back down into a pair of 3-inch mufflers with turn-downs. The theory behind this design is that it will keep the velocity of the exhaust gases moving quickly through the headers into the X-pipe to maximize the scavenging effect, while the larger-diameter tubing ahead of the mufflers prevents the gasses from stacking up as they pass through the mufflers to avoid excessive backpressure in the system.
Sounds good, but would it work? To find out, we tested three exhaust-system configurations on Magnaflow’s in-house Dynojet. For a baseline, we ran the car with open headers and saw 333 hp at 6,300 rpm and 304 lb-ft of torque at 5,200 at the rear wheels. Next, we ran a 2-½-inch bolt-together system consisting of a BBK short off-road H-pipe designed to fit the company’s full-length headers connected to a set of race-type 2-½-inch welded mufflers with turndowns. Our Mustang’s carbureted 302 didn’t like this combo, as power fell to 323 hp at 6,300 rpm and 295 lb-ft of torque at 5,200. The increased backpressure also richened up the air/fuel mixture by about two carburetor jet sizes.
Finally, we swapped on the stepped X-pipe setup and were impressed to see power levels equal to the open headers: 335 hp at 6,300 hp and 302 lb-ft at 5,200. That’s a gain of 12 rear-wheel horsepower, although it turns out we weren’t really giving anything up or gaining anything extra from the open headers. So the car’s happy, and our ears are even happier!
08-21-2007, 08:45 PM
#39
MBWorld Fanatic!
lol! 
yes, one set of vrp 200 cell metal matrix race cats in the secondary cat location with no resonator.
imho, it's not so much that the primary cats are overly restrictive but rather their location which is preventing flow out of the manifolds. since you already have shorty headers, you should see a small gain from doing this. considering how much it costs us to bolt-on hp, it's a bargain for the 10hp comparatively speaking.
i didn't but there was considerable weight savings
iirc, an h-pipe helps equalize pressure while a properly fabricated x-pipe can actually increase velocity/scavenging. i'm sure arguements could be made for both and there may not be a significant hp difference between them but imho the benefit goes to the x-pipe.
see below...
chris at floored fabrication in mesa, az custom fabbed the entire system.
forget titanium, regardless of all the hype, it's a poor choice of metal for exhaust applications. if you want weight savings and the ultimate system, it should be built from inconel steel.
yes, one set of vrp 200 cell metal matrix race cats in the secondary cat location with no resonator.
i didn't but there was considerable weight savings
iirc, an h-pipe helps equalize pressure while a properly fabricated x-pipe can actually increase velocity/scavenging. i'm sure arguements could be made for both and there may not be a significant hp difference between them but imho the benefit goes to the x-pipe.
see below...
Can you let me know who built that again. I was talking to them about doing the sl manifolds but wasnt sure if they new how much work it would be. I also wonder if they make the headers, exhaust all out of titanium if that would shave alot of weight? We could just use the factory mufflers?
forget titanium, regardless of all the hype, it's a poor choice of metal for exhaust applications. if you want weight savings and the ultimate system, it should be built from inconel steel.
08-21-2007, 08:51 PM
#40
MBWorld Fanatic!
Would there be any meaningful gains and how much to an N/A engine like my SLK 55 if I were to replace both sets of cats with race cats or remove primary and replace secondaries and add an xpipe in place of the resonator? I'd like some extra umph from the SLK but I don't want to go crazy such as a blower. It's jumpy enough as it is. Cats and xpipe are fairly cheap if they're worth the ponies. I imagine weight savings would be good to. I still have the stock 'headers', can't convince myself to spend $5k on replacements for what is only a few hundred dollars worth of metal.
2.Yes you can put an X-pipe in place of the resonator while your at it and I guarantee you'll feel a difference.
3. You can leave stck mani's and the primary cats and just replace the secondary cats with 200 cell cats and replace the reso with an x-pipe and you'll pick up HP. I tried all the scenarios mentioned and felt a positive difference in each case. i did this one b4 I put headers on the car and the mid range and topend power was very strong.
4, yes you will have a weight difference which will be noticeable too.
08-21-2007, 08:59 PM
#41
MBWorld Fanatic!
I agree on a N/A car, however I think a supercharged car needs back pressure. From what I remember, I think VRUS car lost hp with his new exhaust set-up. I might keep my secondary cats and the resonator and simply eliminate the primary cats. I think this will give the biggest impact over stock exhaust. I have seen some board members complain about loss of tq and hp from also removing secondary cats. A racing secondary cat might hurt as opposed to help if that were the case. How much does the stock exhaust weigh? Chiromikey did you weigh your stock exhaust vs your new exhaust?
Anyway I say get rid of the primaries,replace the secondary's and you will be good to go. And get rid of the heavy *** stck reso and use two Stainless Steel Vibrant resonators. Place an Stainless Steel X-pipe(From Burns) b4 your secondary cats as well. Like Chiro says this will increase the velocity in your exh.
Decision is yours bro I've shared every thing I can.
Last edited by ProjectC55; 08-21-2007 at 09:03 PM.
08-21-2007, 09:07 PM
#42
MBWorld Fanatic!
Nope the bottle neck is more from the stck exh manifold and where the primary cats are placed. PTE gave me the break down on the whole thing and I built my exh very similar to his CLK55with some ideas from Chiromikey as well.
x-pipe wrks way better than an H-pipe read:
old post:
x-pipe wrks way better than an H-pipe read:
old post:
But for me this thread is about an e55 with aftermarket headers asking about primary cat removal. The primary cats are worth an additional 10 rwhp after the headers, further mods to the exhaust on an e55 will yield very little gains. Like I said this is from my experience and if someone has different data of large increases on an e55 please post.
An e55 with the above mods of headers and no primary cats will gain more power from an increase in exhaust valve flow than an aftermarket exhaust imho, hence my comment about the bottleneck.
08-21-2007, 09:32 PM
#44
MBWorld Fanatic!
Good data about the comparison between x and H.
But for me this thread is about an e55 with aftermarket headers asking about primary cat removal. The primary cats are worth an additional 10 rwhp after the headers, further mods to the exhaust on an e55 will yield very little gains. Like I said this is from my experience and if someone has different data of large increases on an e55 please post.
An e55 with the above mods of headers and no primary cats will gain more power from an increase in exhaust valve flow than an aftermarket exhaust imho, hence my comment about the bottleneck.
But for me this thread is about an e55 with aftermarket headers asking about primary cat removal. The primary cats are worth an additional 10 rwhp after the headers, further mods to the exhaust on an e55 will yield very little gains. Like I said this is from my experience and if someone has different data of large increases on an e55 please post.
An e55 with the above mods of headers and no primary cats will gain more power from an increase in exhaust valve flow than an aftermarket exhaust imho, hence my comment about the bottleneck.
Scenerios:
1.primary cats with after market secondary cats plus biger diameter pipes,adefinite hp increase and feel thru the whole rpm range!
2. Placed headers and eliminated primary cats and got more of a HP increase
3. Installed Cams, basically icing on the cake and car holds and makes more power up to the rev limiter and sometimes beyond for some reason.
Now the exh pipe on the W211 E55 maybe the perfect diameter and bigger than the diameter of the old stck pipes that were on my car now that I think about it. I'd minus the primary cats like you have said,the reso with two aftermarket ones,an X-pipe and replace the secondaries with high flow cats. Significant weight savings and an increase in hp . You're right,perhaps not as dramatic as the increase was on my car because I forgot that the stck pipes on my car are smaller than the stck pipes on the W211 E55.
Last edited by ProjectC55; 08-21-2007 at 09:50 PM.
08-21-2007, 10:39 PM
#45
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Very interesting post and awesome pics. Would like to hear a consensus recommendation for the 55. Also, using the overall knowledge what can be done for the E63 (needs all the help it can get). Thanks in advance.
08-21-2007, 11:44 PM
#47
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Yes, thank you everyone for all the useful information.
As I see it, the options boil down to this.
1) Open up the primary cat and gut it out or replace it with straight pipes.
I think this will yield about 10rwhp above current system.
2) Replace the entire system, from my shorty headers back with a Supersprint system. This would cost about $8400 and I think I would gain 10-15rwhp above current system.
3) Custom build an exhaust system from my headers back. Eliminate the primary cats. Install secondary racing cats and aftermarket resonator. This might yield 10-15 additional rwhp.
I would note that in scenarios 2 and 3, I would reduce weight as the stock system is very heavy. I don't know how heavy. Maybe 100-150 pounds. I believe 100 pounds of unsprung weight is equivalent to 400 pounds of static weight. However, this is not unsprung weight. It is static weight. Not sure how beneficial it is to eliminate 100 pounds on a 4000 pound vehicle.
For the money, I think scenario number one is by far the best.
As I see it, the options boil down to this.
1) Open up the primary cat and gut it out or replace it with straight pipes.
I think this will yield about 10rwhp above current system.
2) Replace the entire system, from my shorty headers back with a Supersprint system. This would cost about $8400 and I think I would gain 10-15rwhp above current system.
3) Custom build an exhaust system from my headers back. Eliminate the primary cats. Install secondary racing cats and aftermarket resonator. This might yield 10-15 additional rwhp.
I would note that in scenarios 2 and 3, I would reduce weight as the stock system is very heavy. I don't know how heavy. Maybe 100-150 pounds. I believe 100 pounds of unsprung weight is equivalent to 400 pounds of static weight. However, this is not unsprung weight. It is static weight. Not sure how beneficial it is to eliminate 100 pounds on a 4000 pound vehicle.
For the money, I think scenario number one is by far the best.
08-22-2007, 02:11 AM
#48
MBWorld Fanatic!
ъ
Frank,
I looked at both and they are pretty restrictive...Definately remove PRIMARY CATS !!! The car will pass emissions with just secondary cats...
Primary Cats give the most POWER...As Cory Kleemann said 15HP at the wheels on Dyno and you car feel it...
Its not hard to remove them and make long tubes instead, place you rear O2 sensors which are behind Primary cats, behind the Secodary cats and you wont have any SES light and wont have to adjsut your ECU ...just extend wire by wire...its not very hard to do...
I went throught this...I had regular bolt headers before...then remove Primary Cats and later Secondary...
Secodary Cats dont make to much power, and again Vadim and Cory told ME they aree they are least worth 5-10HP at the crank...
I WOULD NOT reccomend removing just Secondaries and keeping Primaries...As I beleive, the system becomes too Freeflowing after Primary Cats (if primaries a not removed) and you could loose torgues !!!
IMHO here not enough FLOW rate since Primaries are restricting the flow and not enough flow from Primary Cats for gases to leave fast enough with Secodaries removed, cuase again primaries reduce that speed...and that us why Vic55 lossed torgues before when he removed Secodaries and installed E.Race mufflers...
So basiaclly gases come fast to Primaries then slow down and then if we remove Secodary cats the speed increeases but not from the Headers but from Primaries and that is not the same...not enough pressure from primaries, since speed and decreased and the rest of the exhaust to to freem so gases stqay longer inthe system or something like this...
The system becomes to freeflowing for gases to leave fast enough or may be the gases get colder and that means the dont leave the system fast enough, cause the slowed down already...anyways that my theory...every one knows that LONG TUBES Header make the most POWER !!!
Its hard to explain...just remove Primary Cats and you will be happy my friend
Frank,
I looked at both and they are pretty restrictive...Definately remove PRIMARY CATS !!! The car will pass emissions with just secondary cats...
Primary Cats give the most POWER...As Cory Kleemann said 15HP at the wheels on Dyno and you car feel it...
Its not hard to remove them and make long tubes instead, place you rear O2 sensors which are behind Primary cats, behind the Secodary cats and you wont have any SES light and wont have to adjsut your ECU ...just extend wire by wire...its not very hard to do...
I went throught this...I had regular bolt headers before...then remove Primary Cats and later Secondary...
Secodary Cats dont make to much power, and again Vadim and Cory told ME they aree they are least worth 5-10HP at the crank...
I WOULD NOT reccomend removing just Secondaries and keeping Primaries...As I beleive, the system becomes too Freeflowing after Primary Cats (if primaries a not removed) and you could loose torgues !!!
IMHO here not enough FLOW rate since Primaries are restricting the flow and not enough flow from Primary Cats for gases to leave fast enough with Secodaries removed, cuase again primaries reduce that speed...and that us why Vic55 lossed torgues before when he removed Secodaries and installed E.Race mufflers...
So basiaclly gases come fast to Primaries then slow down and then if we remove Secodary cats the speed increeases but not from the Headers but from Primaries and that is not the same...not enough pressure from primaries, since speed and decreased and the rest of the exhaust to to freem so gases stqay longer inthe system or something like this...
The system becomes to freeflowing for gases to leave fast enough or may be the gases get colder and that means the dont leave the system fast enough, cause the slowed down already...anyways that my theory...every one knows that LONG TUBES Header make the most POWER !!!
Its hard to explain...just remove Primary Cats and you will be happy my friend
? is this what they call opening up the exhaust?Is going for the x pipe set up worth it? is it costly?
does this mod get effected by other mods?
guys your comments, experience and pics are amazing!!! please keep up the good work
Last edited by Zod; 08-22-2007 at 02:19 AM.
08-22-2007, 02:20 AM
#49
MBWorld Fanatic!
I plan on taking out the primary cats and replacing with straight pipes then moving the o2 sensor back behind secondary and replacing them with racing cats. Then pop out the resonator and replace with an x-pipe in my SLK. That should give me some nice gains, and the weight savings will be nice as the SLK isn't as heavy as the E to begin with so it should be more noticable. Then put a set of underdrive pulleys on it and it should have a lot more pep.
What do you guys think? Sound good? Shouldn't be more than $1200 together.
If I can squeeze even 20-25 rwhp out if it I'll be happy and much cheaper than other options like $5000 headers or $1000 ecu that adds 8hp. The extra growl will be nice to.
What do you guys think? Sound good? Shouldn't be more than $1200 together.
If I can squeeze even 20-25 rwhp out if it I'll be happy and much cheaper than other options like $5000 headers or $1000 ecu that adds 8hp. The extra growl will be nice to.
Last edited by bfnnrgn; 08-22-2007 at 02:23 AM.
08-22-2007, 02:46 AM
#50
MBWorld Fanatic!
quick heads-up:
after removing the primary cats...relocating the o2 sensor to the secondary cat position is not a sure fix for preventing a cel. some have had success but be forewarned that many have needed a tuner to turn off that annoying cel via ecu programming.
after removing the primary cats...relocating the o2 sensor to the secondary cat position is not a sure fix for preventing a cel. some have had success but be forewarned that many have needed a tuner to turn off that annoying cel via ecu programming.
