time for a tune up or just cat delete?

[vinnye191]

my 94 na has always been sluggish and i assumed it was just because im missing 2 turbos with this one, but im beginning to wonder. it has stillen headers and mufflers with stock cats and a pop charger. when i bought it the kid recommended i do spark plugs because he claimed "i mean i like to change them every spring" which i'm translating to "they might have been replaced since the 90s but probably not". now a week ago we did a muffler delete just to see how it sounded and the car is so loud, its raspier than a fleet of hondas by 2500rpm and louder than any truck ive taken the muffler off of, but removing the mufflers relieved ZERO back pressure and there was a thick coating of sludge in my pipes. now with 175k on the clock i wouldnt be surprised if the cats are clogged but i wanted to double check incase anyone has other suggestions. this winter it should be getting bigger injectors, new plugs ect. as prep for some boost related misadventures but for now will getting rid of the cats help at all? it feels like it wants to go but cant and the higher it revs the more it feels like its suffocating, also my test shows its impossible to spin the tires in 2nd gear even dumping the clutch at the redline(i dont abuse the car like that usually). for reference the power feels like a stock frs/brz except very noticeably slower... also if anyone knows of other cars i could take a starter from that may be useful info too, thanks

[vinnye191]

jeez i meant for this to be a simple paragraph. maybe i should take my adhd meds more often..

[NolimitZ32]

In short, if it feels like a stock BRZ then you are on in the ball park of a stock NA, these cars are not super fast or super powerful,the factory 1/4 mile times for an NA are north of 15 seconds.

[DCaff300ZX]

^^^yep, and ESPECIALLY the ones where the owner does clutch drops from redline on a 176k motor with known issues, and thinks that boosting an NA is somehow a good thing.

[evildky]

1990 Z32 na, zero -sixty = 7.0 Quarter mile = 15.4, later heavier models would be a bit slower
BRZ Zero - sixty =6.1, quarter mile = 14.6

[vinnye191]

not to go full keyboard warrior here but i dont appreciate typical responses. im sure i have some bad habits in terms of phone-grammar but every time i ask a question on a forum i get blatant responses from people who assume im just another clueless fruitbag. i ask those questions because nobody ever answers them they just say to sell it and buy a twin turbo. im not buying another twin turbo unless i find a mint one like the black 92 i saw with 10k miles on it. if i dont find another one like that id rather build one myself. my boost plans also involve a rebuild with forged internals and slightly decompressed pistons. i obviously know other z owners and my friend's 1990 z32 definitely feels like its worlds healthier than mine. doesnt it strike anybody else as odd that removing the mufflers made no difference at all in back pressure and the car still feels like its being strangled above 3k rpm? my friends 90 feels like its got plenty of get up and go in comparison. yesterday i even drove another toyobaru with just a custom exhaust. it felt like it would blow the doors off my car. brutally. lastly i know all 3 of you have posted about 70% of the useful info ive read here before but with all due respect im not an idiot who thinks he can build a car because he's watched gas monkey once. not that this means anything to any of you but i built dirt bikes when i was little and cars took over once i got my license. im currently helping a friend with a 700+whp cummins build. just a daily street truck. he always asks me first every time hes not sure about how/why/what he should do next. i had a nice original midnight blue tt as soon as i could drive, it was almost perfect with the hks hipers and the pop intake. just needed test pipes and a tune but it was taken from me too soon and now id rather build exactly what i want this time. someday maybe ill get into the habbit of typing better and eventually i will make this car better than my old twin turbo but until then perhaps i should change my name to blackZheep since my mentality is generally frowned upon here and i dont have anything to show yet. cheers anyway.

[NolimitZ32]

1. Your butt dyno may be lying to you or there is something seriously wrong with your car if your friend's car feels MUCH peppier than yours as the difference between a 25 year old NA Z32 and a very well taken care of and full bolt-on 25 year old Z32 will be 0.5 seconds in the quarter at best.
2. If you think that removing mufflers will increase your performance you have A LOT of studying to do, exhaust tuning is a lot more about exhaust velocity and scavenging rather than "back-pressure"
3. The reason that you keep hearing the same "buy a TT" and "NA performance isn't worth the money" is because it is tried and true. There is a member on this forum with the sn Honad, reach out to him and maybe he will help you out if you ask politely. He owns one of the cleanest (in terms of mechanics) NAs I have seen on this side of the pacific, with every bolt-on, suspension, and weight shaving measure available for these cars his NA is no slouch but it still is about in line with a BRZ on coilovers.
4. If your cats are clogged removing them should lend some top end power but a proper and full tune up is always a good idea too. However be weary as removing factory emissions components even on a classic car not requiring emissions inspection may be illegal in your jurisdiction.
5. lastly, and this is UTTERLY important on this forum. Please use proper grammar and punctuation, not because we are all English professors in here but because a properly written sentence or paragraph is much easier to follow and will generally yield much more positive replies.