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Magnaflow CARB Legal Cat Installed...

Hello All! Just purchased 2003 MR2 with 103k miles, love it! Took it to my mechanic, replaced valve cover gasket, seal on rear transmission to driver shaft, alignment, and oil change... all pretty basic except the main cat needs to be replaced.
Please share if this is correct, strange chatter/rattle about 2000 -3000 rpm coming from exhaust, when shifting engine slightly but noticeably bogs a bit dropping a few hundred RPM before accelerating and revving back up, and rattle from cat when tapping it from underneath... main cat to be replaced?
I think so...
If so, what are my options other than us1500 full replacement from Toyota and the Magnaflow system on this thread? I don't see any other universals carb legal on the market and thats what my mechanics muffler guy said as well? The cheapest, but unethical and illegal, is to hook up a 49 state universal but then wont pass smog in a couple years when I need to smog (just passed a couple months ago).
Any ideas please help?
So I went the CARB Magnaflow legal route... my shop guy got it from his supplier for 525 with gaskets. Bolted on pretty easy, sounds good, mostly noticed it freed up some torque (revs dont bog down nearly as much when shifting). Only annoying part is a little bit of a temporary spew/squirt sound when accelerating, hope i get use to that!
 

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Magnaflow CARB Legal Catalytic Converter and Fuel Efficiency

A few observations after running with the new cat...
seems like the engine is breathing a little better but I may be looking for confirming evidence since I did blow nice chunk of change...
so i decided to compare my mpg to see if my new cat made a difference in fuel economy... nope.
still 30mpg.
So IF the new cat was necessary and IF it freed up some torque/hp, then it does not translate to better efficiency.
OR I needlessly blew about us$600 bucks.

So I went the CARB Magnaflow legal route... my shop guy got it from his supplier for 525 with gaskets. Bolted on pretty easy, sounds good, mostly noticed it freed up some torque (revs dont bog down nearly as much when shifting). Only annoying part is a little bit of a temporary spew/squirt sound when accelerating, hope i get use to that!
 

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Ok, so those who went this route and replaced their main cat (in Cali), how is the exhaust now? Estee noted a smell and rasp, are those still present? I got an engine in my Spyder, so she runs again but I fear I need to replace the cat as well... taking her to an exhaust/muffler shop to take a look. If I can go the Magnaflow route rather than Toyo, that would be nice, perhaps an upgrade rather than simply a replacement. Thanks for any feedback here.
 

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i just ordered the main cat (57065) as my OEM cat broke off where the piping meets the weave. i live in cali so this was the only choice i had in another cat.
 

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More power with new pre and main cat??

Contemplating purchasing pre cat and main cat to install at the same time as a PEE Magnaflow Dual Catback Exhaust and Injen Short intake. Car has 38,000 miles and I've read alot about the precat failure. Will replacing both the pre and main cats give me more power or would it be just as effective to gut the pre cats and leave the original main cat? Or replace the pre cat with part 56066 and leave the main cat alone?

I will also be upgrading cams soon. I am told that is about all I can do to increase performance and be in compliance with the California Emission Restrictions.

Any thoughts or comments before I blow a chunk of money? New at this, but want to do it right the first time --Thanks.
 

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Contemplating purchasing pre cat and main cat to install at the same time as a PEE Magnaflow Dual Catback Exhaust and Injen Short intake. Car has 38,000 miles and I've read alot about the precat failure. Will replacing both the pre and main cats give me more power or would it be just as effective to gut the pre cats and leave the original main cat? Or replace the pre cat with part 56066 and leave the main cat alone?

I will also be upgrading cams soon. I am told that is about all I can do to increase performance and be in compliance with the California Emission Restrictions.

Any thoughts or comments before I blow a chunk of money? New at this, but want to do it right the first time --Thanks.
I suggest reading the MAF Mod in the performance section. That will give you the increase in performance you're looking for.
 

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No one has really tested the Magnaflow parts as performance mods. If your car is an '00-'02 then you want to gut your precat regardless. I'd suggest you buy someone else's precat to gut because as your main cat ages you'll probably need the precat to pass smog. You can work that however you want, but you may be painting yourself into a corner if you gut your only precat.
 

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Those of you guys who are in need of these Magnaflow cat Cali model or federal i can get them fairly cheap if anyone is interested.

PN# 57065 (CA model main cat) $445
PN# 51140 (Federal model main cat) $415

PN# 51259 (CA model manifold pre cat) $579
PN# 24066 (Federal model manifold pre cat) $475
 

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I was considering to buy one too. However, I was a bit hesitant as I was thinking of 2 options: 1. Buying the mid pipe that you posted. OR 2. Buying the universal CARB legal cat and having it welded onto the JNZ non-cat that I have.

Any chance you can measure the piping between the flange and the flex pipe? (The stock piping is really restrictive there. I understand this is an emissions piece but I just wanted to know if performance can also be obtained. :p)
I have a 49 states unit (live in NH) that I am getting ready to install. To answer your question, the outside of the stock and the MagnaFlow unit's flex pipe areas are about the same. Looking down into the flex pipe from the flange, the stock unit has a considerable restriction in diameter, the inside of the flex area is maybe 3/8 of an inch smaller than the inside diameter of the pipes themselves. The MagnaFlow unit has virtually no reduction in inside diameter inside the flex pipe, it is almost a straight shot through the flex area.

I am, however, going back and forth with MagnaFlow's tech people about some gasket problems. The MagnaFlow downpipes are about 60 thou larger in diameter than the stock pipes and the stock gaskets will not fit over them. Several mentions of stock gaskets not fitting have been made in this thread. The obvious solution is to find a slightly larger gasket, and I will in order to mount my pipe and get the car on the road, but MagnaFlow will hopefully either fix the size error or start providing gaskets with the unit.

Also, at the muffler end of the unit, the new one has a flat flange. The stock unit has a step in the flange that sits the gasket up into the joint. Without that step, getting that joint to work right may be a problem. I am working with Magnaflow on that one, too. They seem very friendly and capable and truly want the parts to bolt right up. They are looking over the pics and measurements I have sent them.
 

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Update -- I have the MagnaFlow main cat installed now. No leaks or other sounds described by earlier postings. It sounds pretty much stock, maybe just a little more gutteral, maybe not. I went to a lot of effort to make this unit fit better than it would have fit right out of the box.

I started by dry fitting the unit into the car without gaskets and comparing that to how the OEM unit fit. I had to grind tapers onto the ends of the downpipes where they entered the exhaust manifold/pre-cat unit and also grind off about a sixteenth of an inch of length before they would fit into the joint the same way the stock unit did. It needs to fit in that deeply or that joint will end up being an exhaust leak, in my opinion. The muffler end of the MagnaFlow unit bottomed out in the ball joint type connection, but I did not need to do any grinding because the joint fit fine once I added a step to the flange as described below.

At the engine end, the stock Toyota gaskets will not fit over the MagnaFlow pipes, the new pipes are slightly larger in diameter than the stock pipes. I went down to NAPA and went parts bin hunting, and I came up with a NAPA 31332 gasket. That gasket is supposed to be for some model of Chevy Geo but it works on the MagnaFlow downpipes just fine. Takes two gaskets, of course, for the two downpipes.

At the muffler end, the MagnaFlow flange is flat and also very thick. The stock flange is about eighty thousanths thick and has a step formed into it that holds the donut gasket up into the joint, which is a spring loaded ball joint. I machined up a step, about a quarter inch tall, inside diameter sized to be a very snug fit on the pipe, outside diameter sized to be the same as the wide base of the gasket, and tapped it over the pipe and hard against the flat flange. This put the gasket in the right spot in the joint and allowed the flanges to stay seperated so the joint could move a little bit on the spring loaded ball joint. If you do not add this step to the flange the MagnaFlow pipe bottoms out in the top of the ball joint. Also, the flange faces are just about touching, which means the joint will not be able to move much, if any, on the ball joint before the flange faces stop the motion.

Also at the muffler end, that thick flange means that the springs that compress the joint will be totally compressed before the stock shoulder bolt bottoms out against the upper flange. I went to a good hardware store and got two 10 mm, 1.25 thread pitch grade 10.9 bolts in a 70 mm length. (Metric grade 10.9 is about the same as our SAE grade 8 bolts, by the way). A length of 75 mm would be better, but to get that length I would have had to buy a lower grade bolt. I wanted to keep the bolt grade high and 70 mm is enough, just barely, so I went with it. I also got two 10 mm fender washers. The washers keep the spring captive, the bolt heads are not large enough diameter to retain the springs. The final purchase was two 10mm by 1.25 thread jam nuts (half the height of regular nuts, used to lock, or jam, a threaded connection.) The bolts/fender washers get screwed into the joint flange with the stock springs on them and tightened down until the springs are well compressed but still have air between the coils of the springs. The bolt is long enough to be sticking out the top of the muffler flange when the springs are compressed, and the jam nuts are tightened firmly onto the ends of the bolts so that they cannot loosen in the joint.

Of course I put high temperature anti-seize compound (the copper stuff, not the zinc stuff) on all the threaded connections before the final assembly.

The MagnaFlow has no provision for an exhaust hanger prong on the case of the main cat. It also has no heat shields. The OEM unit has a hanger prong that goes into a rubber donut mount to support the weight of the cat and the associated pipes. It looks like the new unit (which is slightly lighter than the OEM unit) is fairly well supported without that hanger, but I worry about longevity. We shall see. If I start getting worried, I can weld up something that attaches to the pipe with a big muffler clamp and has a hanger prong on it. We shall see how it does without the heatshields, also. The OEM unit is almost all enclosed in heat shields -- the pipes and the cat, so I hope the unshielded unit does not melt anything down below.

Finally, I should mention that this car is totally stock, including still having all the under body plastic panel things. The MagnaFlow cat is located a little aft of the stock cat's location and ends up actually lightly touching that black plastic panel that goes from the bottom of the bumper skin forward to join the under-engine black plastic panel. Since the new cat has no heatshields, I was certain it would melt the plastic panel thing, maybe even set it on fire, so the car no longer has the black plastic panel under the rear bumper skin.

I have relayed all my comments and suggestions to MagnaFlow. I think they have nerve calling this a "direct fit" unit. I also think they will improve it, they seemed truly unhappy about the situation and say they will fix it.

Short version -- it will bolt right up if you do not mind a mediocre fit and most likely some exhaust leaks, you just need to get those Geo gaskets. With a fair amount of effort and a little bit of machine shop work, it fits pretty darn well. Hopefully they will rework it and it will become a true direct fit unit.
 

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One more thing.........

I forgot to mention that I installed the MagnaFlow 51140 unit. I believe it to be dimensionally identical to the CARB legal unit and also to the less expensive version of the 49 states unit. The only difference between the units is the size and capability of the cat that is welded to the pipes, the pipes and flanges and stuff are all the same.
 

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I was hoping we'd hear back from you on the fitment issues. Thanks for describing how it went. We'll see if magnaflow cleans things up. I get the impression they are capable of making some really good stuff, but I have a feeling that they don't have a lot of feedback from the ever shrinking pool of remaining MR2s.
 

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The cost of the unit just dropped $106

I took the old OEM cat converter and also a bag with the contents of the pre-cats (I gutted the pre-cats while I had the exhaust system taken apart, might as well) to an auto salvage yard. I got $106 for them. The cats have rare metals in them that can be reclaimed. Anyhow, I wanted to share that so that folks will know to not just throw out their old cat and/or the contents of the pre-cat if you gut yours.

So far the newly installed MagnaFlow main cat with pipes and the newly gutted pre-cats are working fine with no exhaust leaks or odd noises. Yaayyyy!
 

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Has anyone installed the Magnaflow precats? If so, were there any fitment issues there? I would assume (optimistically) that there wouldn't be a difference between the 49 state and the CA, though I am in CA if that makes a difference. I'm thinking about going that route so was curious. Thanks!

James
 

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Has anyone installed the Magnaflow precats? If so, were there any fitment issues there? I would assume (optimistically) that there wouldn't be a difference between the 49 state and the CA, though I am in CA if that makes a difference. I'm thinking about going that route so was curious. Thanks!

James
Post number 33 in this same thread talks about installing the MagnaFlow precats. Check it out.
 

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Has anyone installed the Magnaflow precats? If so, were there any fitment issues there? I would assume (optimistically) that there wouldn't be a difference between the 49 state and the CA, though I am in CA if that makes a difference. I'm thinking about going that route so was curious. Thanks!

James
The most significant difference between the two units is probably that one has a stamp on it indicating it's CARB certified....and therefore will pass smog in CA if you have an attentive smog tech. I doubt anyone has had both units next to each other to look for any visible differences, if there are any.

Keep in mind that brand new Toyota OEM pre-cats are $200-300 cheaper from online discount Toyota parts dealers than the CARB legal Magnaflow pre-cats.
 

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Post number 33 in this same thread talks about installing the MagnaFlow precats. Check it out.
Ugh, sorry about that! I've been watching this thread but I must have been thinking about my main cat when that post went up.

The most significant difference between the two units is probably that one has a stamp on it indicating it's CARB certified....and therefore will pass smog in CA if you have an attentive smog tech. I doubt anyone has had both units next to each other to look for any visible differences, if there are any.

Keep in mind that brand new Toyota OEM pre-cats are $200-300 cheaper from online discount Toyota parts dealers than the CARB legal Magnaflow pre-cats.
Makes sense. Since Toyota has fixed the problem they had with their pre-cats, the only reason to go aftermarket would be for some type of performance gains or money savings. Also, I would have no concerns about fittings being as it is Toyota parts. That may be the route to go. Thanks for the wake-up call.

James
 

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I know it has been asked here before, but I haven't found a definitive answer. Does anyone know the exact differences between a Fed main cat and a CARB one? Has anyone done a side by side comparision? Any known differences in the internals? Will a Fed cat work in place of my CARB cat with a direct fit? Will it perform just as well as a CARB? I am thinking that there is really no difference but the stamping.

Thanks!
 

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This is second hand info, so do not take it as the gospel truth. However, when I sold the guts of my precat and also my physically broken stock main cat to a local salvage yard, I got to talk to the yard's "cat man". He mentioned to me that the difference between aftermarket cats, OEM 49 states cats and OEM and aftermarket CARB legal cats is the amount of rare metals in them. The more of the catalytic metals there are in the unit, the better job it does of doing its job. Also, as the unit ages and looses some of its effectiveness, the units with more expensive rare metals in them will still do a legal job of cleaning up the exhaust gasses. The cheaper units with less rare metals stop meeting standards sooner.

Aftermarket cats have to meet a much lower standard of performance and longevity than 49 states OEM cats. All CARB legal cats (OEM or aftermarket replacement) need to meet an even higher standard of longevity and effectiveness so they have the most rare metals in them.

So, the cases and pipes are all pretty much the same. The higher up the chain they are the more rare metals are inside them in order to meet higher performance and longevity goals. That is why a salvage yard needs a "cat man" who can judge the type of unit pretty much on sight. A lower grade unit will have less rare metals in it and be worth less money to the salvage yard than a CARB unit would have, yet they all pretty much look that same from the outside. They do not want to pay you too much so they want to know what type of Cat you are offering them.

So, to your question -- they are all physically about the same but they do not all have the same expected service life or level of expected clean air coming out of them. The better ones look pretty much the same as the cheaper ones but they have much higher amounts of expensive rare metal inside them to do a better job of catalyzing/cleaning the exhaust and to do that better job for a long long time. A cheap one would pass a California smog check for a while, but would start flunking much sooner than a unit that was higher up the totem pole. To try to keep folks honest, the CARB folks require units they approve to be marked with that approval. They do not want sub-standard units that will start polluting prematurely.

Again, that is second hand, but that is my understanding.
 
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