will my car sound bad with no cat and no muffler?
 

kinda thinkn about gutting or removiing the the cat and removing stock muffler and doing what ever other free mods i can to make this thing go a lil faster. i got an idiot with a 90 taurus sho 5 speed who wants to race and i want to humiliate him cus hes a shyt talker, even though he knows his car is a flat 15 car at best he wants to race and i wanna destroy him.
As my car sitts it has 107k on the lt1 and body, the trans has 20k and the low reverse captive check ball has been removed. i have an exhauste leak on my passenger side and maybe a failing opti spark or bad grounds some place and a k&n intake, removed my hypertech pcm. i dont know if these cars are any good from a roll, its kinda a personal thing or normally i wouldnt mess around. help me murder a sho taurus idiot:)

You asked if the car will sound bad if you do away with the cat and muffler. The answer is yes, in the true meaning of the word, especially on a long drive. lol

...And, what's he gonna do with all that "lost" back pressure too? ;)

I took my muffler off last summer just to see what it would sound like. It sounds good at idle, but when you roll into the throttle it sounds really untuned. It just doesn't sound great.

And if you take the muffler off you lose some low end power....I could tell the difference when I took mine off....It seemed to have less pickup

If you want a loud exhaust try the SLP...with just the catback its real loud, and it has a nice sound...But some people don't like the way it sounds...

Its all in what you want, if you want loud then the SLP will make your car sound like a beast.

If your opti is going out you probably aren't making as much power, so you might be in the 15s as well.

Just saying. I think I may have to replace mine soon too.

I am sure that someone in E-Bay is selling a back pressure enhancer for cases just like this one.

Funny you should mention that, someone does make an enhancer: Back Pressure Feedback Tube

Right along with the cross drilled brake lines.

you're killing me :-)

OK... I hope this is a seroius post from the OP. If you want to kill him then the first thing you are gonna need to do is fix the opti and tune the engine properly. Fix the exhaust leak too. I know that you have to go through emissions in Lynnwood so leave the CAT alone or get a performance cat. If you want a good sound then get a tuned muffler like a Magnaflow or Flowmaster 40. You will RUIN and I do mean RUIN your engine if you run open exhaust. You NEED some backpressure for cooling the exhaust valves. This assists the engine in scavenging and also to prevent your valve from burning up. If you remove the CAT and muffler you will start noticing these symptoms:

Loss of power
Pinging
Lower mileage
Failing emission tests before they even plug you in.
Engine running hotter than normal
a headache from all the noise
popping through the intake
and Ford taillights in your front windshield, not Ford headlights in your rear view.

Massey

If by "open exhaust" you mean with no exhaust manifolds on the heads, then yes that's right. Running open shorty headers....maybe. Running open long headers....not as likely. Running with a full length system, even straight pipes...absolutely not. Valve damage (warping) can happen when cold air is sucked back into the heads as the throttle is backed off. That ain't gonna happen with an exhaust system installed.

A friend of mine used to have a racecar that kept losing exhaust valves untill he put a cheap turbo muffler on each header. The valves would have pits in them and would not seal to the head. After the muffler went on the valves would not get pits any more. This was a Hobby stock Monte Carlo with a 350 in it, long headers and pipes running out before the rear wheels. He typically raced on 3/8th mile and 1/2 mile tracks. on mid grade pump gas (which was the stuff that the track provided that we had to use for the class we were running)

Massey

Makes you wonder how they handled back pressure on fighter plane engines. Notice the 4" open pipes.
http://upload.wikimedia.org/wikipedi...aft_engine.jpg

I would guess it had something to do with the slower burning and higher lead content. Also an aircraft does not have constant throttle adjustments like a car does.

I love the sound of those big engines. I remember when I was a kid hearing the Hydroplanes when we went to Lake Washington for SeaFair. Now those were thunderboats!

Massey

there is the answer to your friends issue. If we still had leaded fuel he would not have seen the valve issues. Of course you can always change to a different alloy to combat the unleaded.

It always comes down to cash with these things, doesn't it ???????????

I installed a B&B tri-flow cat back on my 95 and then did a off-road thru pipe.. didnt seem to have any problems with it .. but I would def. fix all of your problems first, and keep a muffler on it, just get a good performance muffler for sound

That class has a $500 rule for the engine. Any other driver in the same class can purchase your engine for $500. This keeps the field even and the guys with the big $$$ will move up into the faster classes. So with that being said he didn't want to dump $500 into the heads and put some stainless valves in the car that would not pit bad. He instead spent $30 for a pair of cheap muffs and fixed the engine!

Massey

ok first off i found this link in a thread on here.
. so just look at and read it, it dispells the backpressure myth. heres the link
exhaust myths:
http://www.popularhotrodding.com/eng...xh/index1.html




heres the tread it was linked in on here
https://camaroforums.com/forum/showt...ght=no+muffler


these 2 other links were in there as well and worth reading for sure
http://www.carcraft.com/techarticles...ion/index.html

http://www.mustangforums.com/forum/2005-2011-mustangs/96138-cross-over-exhaust-pipe-explained.html


and i removed the muffler. personally i think it sounds great. its quiet at an idle and if anything im spinning tires more now on accident. it is a bit too loud but my mustang with a offroad h pipe and 40 series flows dumped at the axle was as loud or louder. my stock muffler tips were all retarded from someone hitting some thing so that kinda why i wanted it off for now , so i could see how they were so crooked. so far all my friends like how it sounds. and we are all in our 30s or older so its not kids going "dude thats bad ***".
ive always gotten horrible gas milage in this car. its never felt slow, exhaust smells like gas, and i can scan it with a obd1 gm code reader the kind the have at schucks/orielly its a innova brand can obd1 & 2. i checked several times, removed the hypertech piggyback still cant scan it. check the connector for loose wires nothing. im not fixing the exhaust leak till i install long tubes, its just not that bad or worth it. it goes away when the cars warmed up. but anyways i need to scan the ecu. and i cant. im sure something is bad here, either both o2s, mass air, map or something but im not going to just throw parts at it. my idle once warm drops to around 600 or so, tach may be off some but its no where near 1000 when cold. so that and issue. but i can smell fuel in the exhaust for sure when i rev it and usally at idle too.

so according to the linked thread back pressure is kinda a myth, if someone wants to show proof it isnt im listening. as far as emissions my cars registered in gold bar so i have no emissions. and unless my cat plugs up i have no problem with it being on the car.

Looking forward to hearing my exhaust sound better than my stock one. I'll be adding some new pipes after replacement engine and headers. As long as I'm doing the switch I might as well do that too. Look @ my page an shoot me some tips to get me scootin. Need a cam too I guess?

replacement engine?? what motor do you have?

Does your car have the OBDII scanner plug or the old school OBDI plug? On some 94 LT1 cars (like Corvette) they moved up to the OBD1.5, and cannot be scanned with an OBDII or I scanner with out an adaptor. I will post an image of it in a little while once I move to my normal computer at my office here. It is just 2 jumper wires so the OBDI scanner can read from the OBDII port.

Massey

obd1 like the old cars, theres only about 5 wires in it. to me that seams odd. i unscrewed it to check that no wires were missing, loose or broken

i have the 12 pin like the one in the link
http://www.obd2allinone.com/sc/toplevel.asp?cat=2
has anyone tried the usb to aldl like in the link?
i want to make my own cable and just hard wire a female usb in.

wow i stumbled on all sorts of stuff. i want to run my laptop and scan my car in real time. so if anyone knows how to do that diy style let me know

http://www.tunercat.com/

http://www.tunerpro.net/

http://www.carputing.com/

I'm looking for the same old 3.8 to go back in it. I'm doing the headers too, looking @ the options on the sticky note on the forum for V6. I found a 02 V6 out of one that is runing for 450.00 W/90k so I'm tring to jump on it. Is that a good deal, because I've checked around Cincinnati an Northern KY and nothing has been this cheap thus far. This one is about 2 and a half hours away in Southern KY. I don't know if their gonna do a waranty. They have one also I initially called on w/60k out of an 02 also for $600.00 but is promised to a guy this Saturday with the matching trans too (added cost of it) but if he don't show for some reason I got dibs on it.

If you have the old connector you may be able to short pins A+B and count the blinks of the CEL. Just short them with a paper clip, turn the ignition to on but engine off. If it works the first code you will get will be 12. This means no tach signal. It also signals when all codes have been read.

Blink... blink.blink.......blink...blink.blink........blink ...blink.blink

This signals 12. Other codes will follow 2 seconds later. The codes go in order from lowest to highest. Once you see 12 again you know there are no more codes in the computer.

94 was the first year of programable memory in the PCM. You do not need to flash your chip or replace it. The links you listed should be able to assist you in making the cable and having the proper software to read and possably remap your settings. Make sure you back up the factory settings first!! VERY IMPORTANT so I will say it again... BACK UP THE FACTORY SETTINGS BEFORE MAKING ANY CHANGES. If not you could be lost with no reference to return to known good settings.

Massey

it doesnt repond to the paper clip /jumping a+b
i saw something about using a 10k resistor for certain tpi cars.
from looking at diagrams all my wires are where they are supposed to be on the aldl, i just remeber my 84 firebird 305 had more wires and you could lock up the converter by jumping pins "f" and "a"
anyways for whatever reason it wont scan. if it requires a 10k resistor to start data stream it would make sense

i cant find a schematic for aldl to usb. only ones ive found is serial to aldl and i dont want to do that way, further more my laptop is new and has no serial crap. and they dont work as well as usb anyways.
far as i can tell the us jumps the a+b and adds a 10k ohm resistor if need be and pin "m" and "e" are tied together feeding data sit cant be complicated unless theres a cuircuit imbedded in either end of the cable

I found the image here it is. This should work with any OBDI scanner.


Massey

er... wait that is for the 95... Grrr Not sure if it will help or not. I have never been able to find ALDL schematics for 94s they are an oddball.

Massey

its possible i need to check all my grounds to the computer and stuff.
also i might need a 10k ohm resistor to jumper it. im getting like 9 mpg so i know something is really wrong

so i still need to find some sorta muffler to kinda tone it down a slight bit but not be restrictive

Hey I know Im coming In a little Late on the Post.. But I was running a best of 13.92 in my 94 Z before some self mods... I did the egr and smog pump removal... a throttle body bypass.. descreened the MAF.... Hallowed out my stock Cat. and cut open a Flowmaster Exhause and hallowed it out so it was just a shell.... It sounded Great...and I was running 13.60's all day..... then later put on a CAI and 3.73's to get down to 13.3's then cracked a Head and Started my Stroker Project!! LoL ... if you wanna see some vids of my car doing it go to youtube and type in wicked94z28 to check it out!!!

very cool.
well if i sort everything out i alread have the k&n cai and 3.73 are stock on my car i think

I dont think 373 come stock man.. I could be wrong tho... If you want to know what it is for sure look in your glove box for a GU and a number mine was GU5 which was a factory option that was 3.23 but not all came with that there was about 4 different options i believe... GU5 is 3.23... GU6 is 3.43.. I believe GU3 is 2.73.. and so on I had a site that told all of them but dont have it anymore.. so if you have a GU number that is different let me know and ill try to help ya some more..(the GU is only for stock vehicles of course)

I agree the SLP catback on my car sounds great. Not too loud at idle but when your drivin it sounds mean.

Mines gu5 so 3.23, hows that an option,what did autos come with normally?

Well I cleaned my grounds near the coil and added a extra ground wire yesterday. Tried scanning the ecu with a innova can obd1&2 still says cant connect. Tried paper clip trick, tried a 10k ohm resistor, cant pull codes. Service engine soon light works but isnt on, im getting around 10mpg, car runs well, any ideas anyone?

I wouldn't purchase an optispark until you've got your codes pulled. That being said, SLP seems to be the clear winner. Also if you like the sound at WOT and are looking for a quiet alternative except when you want to have fun, QTP sells an electronic cutout.

i actually slapped on a Thrush welded flowmaster style it was $37 sounds mean. but its only 2 1/2 in and out single outlet.
i really need to scan this computer. im kinda confused as to why i cant scan it and the 10mpg. ive spent hours reading useless internet crap and stuff on alldata

many autos had 2.73's

test your intake air temp sensor and engine temp sensor http://www.shbox.com/1/4th_gen_tech2.html#ect
the 94 is obd1 but is different from the 93 or 95 you can not flash codes like a 93 but does use a obd1 scanner unfortunatly it has to be compatable.
test your evap system, test fuel pressure regulator and fuel pressure. how old are your 02 sensors, have your injectors ever been cleaned and flow tested? check the maf to see if its dirty. check all plugins for bent or damged pins.