I'm tring to figure out why my 90 lx is so slow now. heres the deal: about a year ago i had a new exhaust system put on my car. i was tuning it for a turbo but haven't done it yet do to no money. the exhaust i put on was custom made 2.5" pipe from exhaust manny all the way back. i had a 2.5" high flow cat with a tec9 hp 2.5" muffler. after i had this done the car lacked alittle low end power and it had a exhaust poping sound when you get off the gas when shifting gears. also the car gets poor gas milage. so i figured its do to the exhaust being to big. so i just got done swaping over a stock setup and connected the exhaust to the 2.5" piping about a foot after it leaves the resinator. i just got done driving it and the car still has the poping noise when you get off the gas and the car still has poor acceleration. i'm not sure what else it can be but i'm open for ideas

 

timing
new wires
different spark plugs
better gas , not from no-name places
better oil
check tranny fluid

 

not to mention o2 sensor.. most likely what you're experiencing is similar to a backfire. opening up your exhaust lets your engine exhale easier, and also may have a small impact on lowend power. when i went from stock to just 2 1/4 inch axle-back (not full cat-back) and a highflow flowmaster, even THEN i 'felt' a hit in the lowend.. as in the car didn't seem to pick up as fast. however, you'll notice your midrange and high end sees the best gains from cat back. i'd say the 2.5 inch piping is the cause of the popping/gurgling you may be getting from the exhaust.. it's common place if you're jumping up exhaust diameter. however, if you're actually going turbo eventually, 2.5 inch exhaust is MUCH more adventageous than 2 1/4 or 2 inch mandrel bent exhaust. currently, i have 2 inch cat back piping with an inline 2 1/4 inch 18 inch long resonator.. i have no popping or backfire.. had i done 2.5 inch.. this would be different
peace

 

ur dumb for using 2.5" exhaust but u know that

 

Your 2.5" exhaust probably ate up your valves from lacking backpressure. It happened to my friend's 323 when he had an exhaust leak, too.

 

hey if u dont want the 2.5 and if it fits my 92 lx ill buy them off you what you think

will they fit???

 

Yea i would go with maybe 2 inch exhaust, more back pressure, more low end torque