Guest TurboSedan Posted June 26, 2003 Report Share Posted June 26, 2003 i used a sawzall and cut the 210,000 mile CAT out today. it's been stinking bad lately and i get shitty gas mileage and a slight power loss from a few months ago. this is the 1st and only engine mod i've done to the car in the 3+ years i've owned it. otherwise it's just been properly maintained since i bought it @ 111,000 miles, but driven rather hard since i deliver pizza and driven even harder once i swapped in the 5-speed i don't beat the hell out of it tho.... so anyway, i am using a temporary 32" long flex pipe with new clamps on each end. it is leaking tho and the car is a little louder than i'd lke. tomarrow morning a local exhaust shop is welding in a 2.25" test pipe in place of my temporary flex pipe so hopefully it will get a little quieter and no exhuast fumes. they are charging me $50-$60, but it's illegal for them to do this and i can't weld anyway. i didn't ask questions or bring up the term 'cat converter' at all. performance gain: i DID lose some low end torque but not much. it doesn't quite rocket off like it used to. i can still roast the tires thru 1st and bark them into 2nd pretty good (on smooth pavement). the MAJOR gain tho is i have WAY WAY more upper RPM acceleration! wow! i actually took the car to 6 grand in 2nd and it was still pulling good. i gained a good 500-700 RPM losing the cat and now the car doesn't fall on it's face like it used to around 40-50mph. i used to shift from 1st to 2nd at about 4500 RPM, but can now go probably up to 5500 now. my car likes 2nd gear the best, and i can bring it up to 6000 RPM pulling hard the whole way. woo-hoo joshua btw, i could just *barely* see any light thru one end of the CAT, and NO light when i looked thru the other. their wasn't anything loose shaking around inside tho. i'm going to try to hollow it out with a broom stick and use it if i have to do a vehical emmision inspecion ever. they don't test in WY for anything, but CO and VA does, which is where i might be moving to in the next couple years. Quote Link to comment Share on other sites More sharing options...
LukeZ34 Posted June 26, 2003 Report Share Posted June 26, 2003 I'm getting the cat removed from the TGP this weekend. Hopefully if John gets a chance while were in Springfield we can get to it. I've been getting terrible gas milage and the exhaust reeks pretty badly too, and with 113K on the stock cat, it's time to remove it. But what you said gives me hope that there's hiding power in the car yet. So I'm hoping that by removing that cat I get some good gains. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted June 27, 2003 Report Share Posted June 27, 2003 Its about time you started modding that thing, Malibuolds!! Robby Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 27, 2003 Report Share Posted June 27, 2003 Its about time you started modding that thing, Malibuolds!! Robby no doubt! it seems all i ever do anymore is collect parts and store them for a later project like my TGP engine, '97+ strut/knuckles for bigger brakes, Addco rear bar, 34mm front bar blah blah. it's all just stored in the garage and waiting to go on. it's nice to finally feel some 'seat of the pants' gain even tho it's fairly minor. the car is much louder now with the flex pipe in there, and i REALLY hope a solid test pipe welded in will quiet it down some. and also get me some better MPG... Luke - good luck, i'm betting you'll feel some better mid-high acceleration. yours probably won't get louder like mine did (cuz your turbo), but chopping my CAT out was definately worth it. i'd spend money on a high flow Catco or Walker, but those things are just too expensive for me at the moment. joshua Quote Link to comment Share on other sites More sharing options...
god910 Posted June 27, 2003 Report Share Posted June 27, 2003 So I'm hoping that by removing that cat I get some good gains. I know more than one turbo car owner that has been upset after removing the convertor. You almost %100 percent of the time will lose some boost. It can be made back up, but just by cutting the kat off you will lose some boost. I can't say anything for the 3.1T but I know every last Mitsu I have run into lost boost after removing the cat. Best of luck. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 27, 2003 Report Share Posted June 27, 2003 i did a midnight trip with the CS and decided to take 1st, 2nd & 3rd gear up to the 6000 RPM redline, flooring it the whole way up to 90mph. way different shift points than before. when racing i now shift from 1st to 2nd @ 35 mph (was 30 mph), then shift from 2nd to 3rd at 65 mph (was 58 mph). i didn't get into 4th gear until 89 mph (was 78 mph), and i was still climbing. i didn't try pushing 4th cuz i was going fast enough already @ 90 mph in 3rd, but i think i can take 4th up to 110 - 115 mph maybe now (just a guess). last week i could barely get the car to pass 100 mph with the old CAT in there and i was trying 4th and 5th. i wonder how far 5th would take me if i had a chip with no speed or rev limiter....i've heard of chipped TGP's clocking over 150 mph, with an auto. i don't have quite as good of an overdrive ratio for top speed (5th gear), but hell i wouldn't have the balls to go over 130 anyway joshua Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 27, 2003 Report Share Posted June 27, 2003 So I'm hoping that by removing that cat I get some good gains. I know more than one turbo car owner that has been upset after removing the convertor. You almost %100 percent of the time will lose some boost. It can be made back up, but just by cutting the kat off you will lose some boost. I can't say anything for the 3.1T but I know every last Mitsu I have run into lost boost after removing the cat. Best of luck. that's wierd, i would think you might gain a little boost by going with a larger or 'free-er' flowing exhaust since it lets the turbo spool up quicker. i have always heard less back pressure is a GOOD thing on turbo engines since the turbo itself creates enough already. or maybe he had a post CAT O2 sensor that was fugging up the computer after the CAT was removed. interesting. joshua Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted June 27, 2003 Report Share Posted June 27, 2003 so anyway, i am using a temporary 32" long flex pipe with new clamps on each end. it is leaking tho and the car is a little louder than i'd lke. tomarrow morning a local exhaust shop is welding in a 2.25" test pipe in place of my temporary flex pipe so hopefully it will get a little quieter and no exhuast fumes. they are charging me $50-$60, but it's illegal for them to do this and i can't weld anyway. i didn't ask questions or bring up the term 'cat converter' at all. the test pipe is in and it is MUCH quieter now with NO fumes at all looks like they did a good clean job and it only cost $57. for the gains i gotta say it was WELL worth it. i'll be checking gas mileage differances and post later. later joshua Quote Link to comment Share on other sites More sharing options...
Bolt_Crank Posted June 27, 2003 Report Share Posted June 27, 2003 awesome! I think Imma be getting mine removed/changed soon... it kinda annoys me... don't know why.... anyway, how do you get the comp to think that the O2 sensor readings are normal? o.o Quote Link to comment Share on other sites More sharing options...
NOHC_WBody Posted June 27, 2003 Report Share Posted June 27, 2003 The OBD1 cars only have one o2 sensor. It's pre-cat, so removing the cat won't cause the readings to differ. The 2nd gen W's have a post cat O2 sensor, which can be tossed right after you get an O2 sim, like the one from Caspers' Quote Link to comment Share on other sites More sharing options...
cutlassdude96 Posted June 28, 2003 Report Share Posted June 28, 2003 its not just the 2nd gen but all cars made from 1996+ that have a O2 sensor after the cat. Quote Link to comment Share on other sites More sharing options...
Lee Posted July 1, 2003 Report Share Posted July 1, 2003 Give the ECM a couple hundred miles to adjust then do your milage test. Mine took a tankful to tune in after getting rid of the cat and going dual 2.25" Later I swapped the Flow Tech glasspack in because of raspiness. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted July 1, 2003 Report Share Posted July 1, 2003 Give the ECM a couple hundred miles to adjust then do your milage test. Mine took a tankful to tune in after getting rid of the cat and going dual 2.25" Later I swapped the Flow Tech glasspack in because of raspiness. yeah that's a good idea. i am still getting crappy city gas mileage (driving FAST). i put 100 miles on it and then checked the MPG and it was like 14.3 MPG on the other hand, i just went to Denver (DIA - Interstate all the way) and i got 22.3 MPG. which is still shitty but i was really hammering on the car and even got the car up to it's fastest ever - 116 MPH twice! it would hit 116 and the car would just shut off for a moment and then everything was fine again. i was in 4th gear and could probably have taken it to 120 MPH with a chip, and then 5th? for the muffler, i'm not sure what to use, but i'm using a Dynomax Super Turbo on my GTS with complete 2.5" mandrel bent exhaust and no cat. the stock downpipe is already 2.5" too. i'll probably go with the same approach with the TGP engine - and it won't be raspy with the TGP cuz of the turbo. the muffler will be installed where the cat was, and then 2.5" mandrel bent pipe all the way to a Y-pipe in the stock location and 2.5" dual tail pipes (fake duals). joshua Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted July 1, 2003 Report Share Posted July 1, 2003 i've driven it a few hundred miles and wanted to add some info about performance gains: i lost very little low end torque but got LOTS more midrange pull. it pulls good up to 5000-5200 RPM, and that's where i shift. it used to be down around 4500 RPMs. what's important is that i gained the higher RPM's (a valve job, new springs, cam & lifters would be nice now). the high RPM pull is still weak (above 5000), but i remember i used to be afraid to rev the engine above 4500 RPM! it's kinda wierd taking 1st & 2nd gear to 6 grand (and get to 60mph fairly quickly ) later, joshua Quote Link to comment Share on other sites More sharing options...
LukeZ34 Posted July 1, 2003 Report Share Posted July 1, 2003 We never got the chance to get to mine, but, I think I may have arrangements to get it done here. Someday it'll happen, lol. Only thing I'm wondering about is the sound of the exhaust. We plan to cut the pipe after the cat, and then remove the down pipe from the turbo pipe, bust up all the ceramic in the cat, remove it, and then clamp it back on with the hollowed cat in place. I'm hoping it doesn't get the exhaust TOO raspy. Considering I pulled a 15.2 at the track, it's time to start fixing up the car. Quote Link to comment Share on other sites More sharing options...
92turboLE Posted July 1, 2003 Report Share Posted July 1, 2003 just a quick thaught... my buddy got an electronic dumpout just before the cat... that way you can go stealth mode and still pass emissions, or open the dump partial or fully (depending on how your car likes backpressure) for racing and whatnot... plus it sounds like a beast with the dump open.... buddy had one on his 96 baretta too and that thing was fun... no one would race us cuz they thaught it was, as we heard from a few ppl, "like a 10 second car" or something... merely by the dumpout being open on a 3100.... the dumpout with wiring and switch was like 65 bux i think... just my two cents - Justin Quote Link to comment Share on other sites More sharing options...
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