Thinking about getting a Magnaflow high flow catalytic converter in place of my secondary converter. looking at about 90 bucks. Is this mod worth it. Will i get noticeably more sound out of my flowmaster muffler???

 

im not sure about sound but gas milage gets better by a little bit and more throttle response. i have one on my 96 but i dont run any mufflers. i think they are definatly worth it. 90 bucks is cheap too. i think i payed almost 200 for mine and i cant remember what brand mine is either.

in other words.... buy it. u wont be disappointed.

 

Get rid of the first cat and run just the second one, the second one will be less clogged so it'll flow better and make it noticably louder. You can even make money if you scrap the cat you took off. If you get a highflow, take off both and scrap them, get a Thunderbolt cat, you can get one for $43 here: http://performance-curve.com/425250-...nvertero2.aspx It even has the O2 sensor bung you just just put the O2 sensor in and go. I have one on my Sierra and it's awesome, makes it a lot louder and flows like a straight pipe, only drawback is it kinda stinks but mine comes out in front of the axle, with a tailpipe you won't notice it at all.

 

My cat is rattling in my 90 S10 Blazer 4.3L, with 270k on the clock...so she's lasted quite a while for being stock. I found an exhaust shop that agreed to replace my cat for $75 installed if I supply my own cat. My concern is whether I should replace it with a stock style unit http://cgi.ebay.com/ebaymotors/Magna...Q5fAccessories that will bolt right in, or trust that the shop can weld in the Thunderbolt unit considering how the stock cat is to the flanges, if they screw up the front/rear location and if it'll start giving me a CEL.

I know for using Magnaflow cats on my 740iL that it's critical that we installed the cats dead center between the front/rear 02 sensors or else people learned the hardway that they'd get a CEL for flow issues. I know the Blazer is only OBDI, but I'm trying to figure out the best way to replace the cat without issues and obviously as cheap as possible considering how old this truck is.

I've even looked at universal cats (which is what's on my 740iL), but this is the first time I've read something about having issues with universals, so I'm hoping for clarification of which universal will work for my engine. From what this site mentions http://www.performancepartswholesale...588+11920+9190 it appears the 94000 series would work since it's 49 state legal (I'm not in CA) and the 91000 series is only for the 2.8L. The pricing on the Thunderbolt is great, and while it's the second time I've come across the name while searching these boards, I only remember that it was used on a Silverado (assuming 5.7L) while my dinky little Blazer is only a 4.3L. Suggestions?

 

Bumpity

 

Go with a Thunderbolt, any decent shop won't screw up the piping to put it in, should be straight forward. It'll flow like a straight pipe and be almost as loud, so that plus a tame muffler like a long Magnaflow or a turbo muffler will sound pretty good, or a Flowmaster will sound nice too but that'd be a bit loud for me, i've heard Flows and no cat or highflows and that's too much for me, I like a low deep rumble that's only loud when I get on it. It won't be bad for a 4.3, it's just like a small block only minus two cylinders, I say go for it. I put one on a 97 Silverado 4.3 with a Thrush Welded muffler and it sounded awesome, very nice tone for a V6 and gave it more power considering the original cat had 260k miles of use.

 

$10 shipping isn't bad. I don't suppose they gave you a coupon code or gift certificate number that could be applied towards your next purchase that you wouldn't mind sharing

 

Not that I know of, didn't give me one when I bought my last one. At any rate it's still a good deal, after two years it still flows like a piece of pipe, everyone tells me it wouldn't last thing long considering how cheap it is, but so far so good. I've only put about 20k miles on it though, and my only complaint is the smell, gives off a nausiating smell but then again I have Ford Lightning style side exits so it's easier to get into the cab, with it all the way out back you can't smell it, I never noticed it with tailpipes.

 

As fast as this truck is, the only people smelling it are going to be behind me anyways....ok, that's a lie

I'm only slightly worried about the noise increase now, but I guess we'll see. If they're too much for my taste, I can always sell it for close to what I paid and still got the stock replacement. Thanks.

Which one did yours look like when you got it? This http://cgi.ebay.com/2-5-Catalytic-Co...item2eafe3567a or this http://cgi.ebay.com/Thunderbolt-High...item5631f4011b

 

Mine looked like the second link, short and smooth no ridges like the first one. Btw what muffler are you running? I can tell you if it'll be loud by which muffler you have, if it's a glasspack, Bullet or straight pipe, it'll be really loud. If you have a Flowmaster 40 or short Magnaflow or similar, it'll be agressive and throaty but not too bad, and if you have a turbo muffler or stock it'll have a nice rumble but be almost silent cruising or at idle, only be able to hear it when you step on it. Lots of guys have these on 4.3 and small block full size trucks, so it'll be similarly loud on yours.