Okay, so last summer I bought a Wagner header for the ol' P5. It's been a great mod. Only trouble is, I was too cheap/ cautious at the time to remove the stock minicat and bolt in a catless downpipe. The Wagner catless downpipe costs 175.00. That's some bucks, and if I could spare two bills at present, I would put it towards a cam instead. However, it's got to be pretty easy to come up with a homegrown catless downpipe.

One suggestion is, to buy the minicat from another Protege (or sacrifice the one I've got) and hollow it out by breaking up the honeycomb inside and shaking it out. The other possibility is, take the stock DP and cut the cat out. Then, find another section of pipe to weld or clamp in its place. Both suggestions are feasible, but I have to imagine that some of the restriction is coming from the bend in the pipe, below the cat. Any way to get a nice mandrel-bent elbow in there instead of the stocker's bend would be better.

My gut (and technical knowledge) tells me that it's better to spend the money (eventually) and do it right. But I have to ask, has anyone had much success with a cheap and dirty homegrown alternative?

 

I was kind of wondering the same about cuting the cat. But the smog testing in Tx start in Sept. And we just cant get any real power out of these cars N/A so I think my modding days for the pro are over. I think I'm gona try to put all for my cash to pay it off and start something new.

 

if you would like I can gut a cat here and clean it up for you. This way you can test it out without damaging your stocker. What do you say $20+shipping for the gutted cat??

 

That's a good deal; I'll let you know. I think a MIL eliminator is about twenty bucks, and I would be in business.

 

I have the MIL's here in stock also,. I can throw it in with the cat for an extra $15(shipped). so $35+shipping is good?

 

35+ shipping is good...
I will PM you with my ship-to address and other details. I think once you have that info, you'll be able to calculate shipping costs.

And for the rest of you guys out there, I will let you know how this mod works out. Think of it as the ultimate high flow cat!

 

any chance you could get a before and after dyno? video clips? time slips?

 

...we'll just have to see how impatient I am to get it in!

What kind of video clip do you want to see?

 

...got it in after work tonight. Just need to put in the MIL eliminator before I start her up. Folks, if you do this, use WD-40 and anti-sieze liberally. You'll thank yourself later. I will post pics and driving impressions later.

Oh, and another note. Matty, as you would expect, came through just as he said he would. I have pics of the parts before the install, and you will be able to see what a nice job he did cleaning up the cat before shipping it.

 

glad everything got to you before your trip. I've pmmed you the MIL install instructions. If you need pictures or the whole document just pm your email address and I'll forward it on.

I think you'll notice a deeper tone but nothing that will be ricey or stand-outish. Also, popping the hood will make everything think you're all stock and confused why you have so much top end!

I'm cureious to see how this works with your Wagner shorty header. I was real impressed with the gains from the header alone so this could be potentially awesome.

 

Hurry up and let me know what you think. If it works I'll be getting one also. Hey Matty, you got any more laying around?

 

i do have another pre-cat here but 2 of the studs are removed....not broken but removed. What this would mean is you'd have to remove two studs from your pre-cat and swap them into this one. I didn't send this one to Darren because we hadn't discussed this part before hand. If you want it though I can make you the same deal. WD-40 and anti-seize and you shouldn't have any problems. I just don't know how strong the threads on those studs...if you break one it';ll never seal right

 

Can't one just buy 2 high heat bolts and nuts for it? Anyways I'm waiting to see how it turns out.

 

finding the right length and thread size/pitch will be more of a hassle I would think. It's up to you and I can guty and strip the pre-cat for you as it is and leave it up to you. Just let me know what you want.

 

Okay, I've been able to test out the car with the "catless cat". The tone is a little deeper and a bit louder, but it sounds quite nice. It was very humid here yesterday, so I should note that my seat of the pants estimation is probably not very accurate. The car feels more responsive than it did. During launch, more of the "sag" below 4500rpm is gone. The engine seems quicker to rev, and nailing the throttle in top gear at 90mph rewarded me with additional acceleration that just wasn't there before. At the low end, dropping the clutch from modest rpm induces more wheel spin, and launches are quicker. It's hard to put a number on it, but if I had to guestimate, I would say at least 3hp would be reasonable (realistic). It probably would have felt like a few more, it is wasn't so darned humid. But, that would put the wagner header and this budget downpipe at around 10-11hp. I don't have any trouble believing that number. This is cheap additional hp, and a great mod to do on a budget. I recommend that anyone with a Wagner shorty give it a shot.

By the way, the MIL eliminator works flawlessly. No check engine light on the road. But, here is some GOOD advice. Do the MIL eliminator when you have the cat out of the car. It is a lot easier to get to the rear O2 sensor from the top of the midpipe. There are shoulders on the sides of the midpipe that a heat shield bolts up to that block the O2 sensor hex from the bottom of the car. I was a dumbass, and installed the MIL eliminator dead last. At 5:45 am, before leaving for a weekend of fishing up north. My solution to putting in the MIL was leaving the O2 in the car, and soldering up the MIL eliminator from underneath the car. It got done, but it's hard to wrap wires from underneath. Put this on your mental checksheet, along with the WD-40 and the high temp anti-sieze.

One more thing - save the heat shield from your stock cat. You will need to install it on the new one, to keep the O2 sensor routed away from the cat. Your O2 sensor wires have special high-temperature insulation on them (silicone, I believe). However, it's better to ensure that they stay cool.