ComancheKid45 Posted December 13, 2008 Posted December 13, 2008 I'm installing a Glasspack tomarrow and am wondering if i should dish out the money for a new Cat or not, I'm in an "visual" insp. county so as long as theres 1 physically there and appearing to be working ill be fine. Basically if theres anything left in mine (OEM) I'm gonna hollow it out, or would anyone advise against that? Will that kill power or anything major? should i just leave it go untouched or should i really look into putting a free flowing or new 1 on it. Truck is an 88 4.0 4x4 Auto, Thanks for any suggestions ;)
JeepcoMJ Posted December 13, 2008 Posted December 13, 2008 go ahead, hollow the cat out, and mount it on your mantlepiece... :brows: be careful on the subject.
mvusse Posted December 13, 2008 Posted December 13, 2008 I am currently (temporarily :D ) running without a cat, running the stock muffler where the cat should be, followed by a glass pack to make it to the next exhaust mount, and a down turn before the rear axle. Get 24mpg highway with a 4.0/aw4 lifted 4.5" if I stick to 65mph. Get about 17 mostly around town with the occasional 5 mile jog on the freeway. Removing the stock muffler from the equation will lower back pressure even more, and might lose you some low end torque. Just a glass pack without a cat might actually be a bit too loud (in my opinion), so you'd have to install a tail pipe all the way to the rear (like stock set up) to quiet it down a bit.
FxRacing282 Posted December 13, 2008 Posted December 13, 2008 up to you. some places its illegial to run an aftermarket exhaust system, like NH. but nobody follows that law. ive read its only like 2ho gain with an empty cat on stock exhaust. but if your running a glass pack then things may be a little worse for you. the engine is designed to have some backpressure and when you get rid of it you compromise power for sound. personally i would leave the cat there with it hollow and then run a glass pack.
BLHTAZ Posted December 13, 2008 Posted December 13, 2008 Mine didn't have a cat on it when I got it. I just run with a Flowmaster 40 Series muffler, single in - dual out...no problems :thumbsup:
ComancheKid45 Posted December 13, 2008 Author Posted December 13, 2008 Alright looks like just hollowing it out (if theres anything left in it) is the logical choice.....ill dig into that later today
bigd44889 Posted December 13, 2008 Posted December 13, 2008 i am running 1 7/8 off manifold into 2 inch thru thrush glasspack tube then 90 up and 90 to the right over frame /under bed out thru side of box runs great more power and torx and yes pritty f'en loud i love it i am in hourn county in ohio no inspections at all just road side and u can avoid them
CWLONGSHOT Posted December 13, 2008 Posted December 13, 2008 I've been there and done that. IMHO, leave the cat as is, or get a HI-FLO cat to replace it. Running without the cat WILL loose you lo end torque. Running a G.P. without a cat will be even worse AND will also pissoff Mom and Dad, the neighbors and the G.F. parents. (FORGET about sneaking her home late)The gain will be non existant unless you drive WOT all the time... Go buy a quality turbo muffler and save for the good cat mount them up and never look back. CW
bigd44889 Posted December 13, 2008 Posted December 13, 2008 first i do drive wot all the time second my nebors are all a#@holes so i like pissing them off lol :cheers: :clapping: :beerhead: :driving:
CWLONGSHOT Posted December 13, 2008 Posted December 13, 2008 first i do drive wot all the time second my nebors are all a#@holes so i like pissing them off lol :cheers: :clapping: :beerhead: :driving: OOH, then have at it man!!.. :brows: :D (But I was talking to comanchekid. :roll: ;) ) CW
ComancheKid45 Posted December 13, 2008 Author Posted December 13, 2008 Well i went ahead and hollowed the Cat out for now, the honeycomb was all white and about ready to expire anyway, The truck sounds much better and really isnt noticably louder at crusing speeds. Someday i might put an aftermarket Cat on it but for now itll work fine ;)
FxRacing282 Posted December 13, 2008 Posted December 13, 2008 white is good. any other color is bad. the stuff on the inside of my camaro was black
ComancheKid45 Posted January 20, 2009 Author Posted January 20, 2009 Alright well I'm digging up this topic again, i did hollowed out the glasspack and installed my 18" Glasspack alittle over a month ago and I'm going back to a muffler setup.....i love the sound but as mentioned low end power is GONE! lol its quite a turd at low RPM and gained very minimum power up high. I would suspect this is due to almost no backpressure. My Lesson is learned and my fix will be to keep the cat hollowed out but install a close to standered muffler to revive some backpressure which should restore most of my Low end torque that has dissapeared. Anyway if this question ever comes up for anyone here's a 1st hand answer, ill let ya know if anything changes after the new muffler install. Hollowed Cat+Glasspack= Awesome sound/ NO POWER! :no:
comanche87 Posted January 20, 2009 Posted January 20, 2009 get a magnaflow cat i got mine off ebay for a good price!!! and its direct fit!! i also put a 3in 2.5in dual out cherry bomb turbo muffler in it!! sounds good!!
702_MJ Posted January 20, 2009 Posted January 20, 2009 i got a magnaflow cat hollowed it out and threw a original 40 series flowmaster on it and it seems peppier to me at the low end. Course its 2.5" header back. Sounds good too. Smokes rangers and toyotas on the street till about 110 and then their highway gears kick in and they go flying by.
ComancheKid45 Posted January 20, 2009 Author Posted January 20, 2009 Cool....I just picked up a Turbo Style muffler online and will get that installed later this week, anyway I'm thinking about reversing my glasspack (its directional) tomarrow for the heck of it & see if that changes anything and also should i put a peice of pipe through my gutted Cat or just leave it hollow and open?
702_MJ Posted January 20, 2009 Posted January 20, 2009 i got a high performance cat and hollowed it and left it, its basically like a resonator now. id just leave it.
ComancheKid45 Posted January 21, 2009 Author Posted January 21, 2009 Alright well i installed my new muffler today......the Sound is still good but quieted down a bit, but my low end Seems 2 be back! :yes: ill see what effect it has on Fuel mileage as well :smart:
CWLONGSHOT Posted January 21, 2009 Posted January 21, 2009 i got a high performance cat and hollowed it and left it, its basically like a resonator now. id just leave it. WHY??? CW
702_MJ Posted January 21, 2009 Posted January 21, 2009 i got a high performance cat and hollowed it and left it, its basically like a resonator now. id just leave it. WHY??? CW Cuz i like it loud, i like it free flowing, i like to annoy old people. The list goes on man. Passed smog just fine. The orignal cat got hollowed by my dad any way so it doesnt matter. Cats to me are just performance robbing.
BREEZE1 Posted January 21, 2009 Posted January 21, 2009 I feel stupid asking this but the turbo style mufflers are the ones that has some sort of fiberglass in them right? Do you think you would have enough back pressure with a freer flowing muffler like flowmaster style. I'm planning on gutting the cat on my xj because you can hear the junk radling around in it. I wanted a flowmaster or something but I don’t want to loose my low end torque….
702_MJ Posted January 22, 2009 Posted January 22, 2009 why do you all talk about losing low end? I have had no problems with my power adders and low end. Banks header(piece of crap) 2.5" custom head pipe, hollowed cat, 2.5" exhaust, flowmaster original 40series, k&n FIPK 2, JET Chip, gettn some OE spec injectors just to get rid of my old ones, and theres alot more to come.
ComancheKid45 Posted January 22, 2009 Author Posted January 22, 2009 Well i can tell ya if you run basically just a straight pipe exhaust youll notice a loss of power when you really need it.....like climbing a mountain on a main road or something along those lines, Itll make alot of noise but i noticed very sluggish performance
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