Protege_Joe

Well we all herd that you cant make a 1.6 fast or a protege for that matter but im going to prove ya'll wrong. My friend who works at master muffler can build me an catless exhaust. cutting the 2 cats off and the resinator. with 2 1/2" stainless still piping along with some headers it will be a tremendous gain in horse he did it to his probe and got like 35-40 horse out of doing so, the cats do limit the power big time. well hope one of you will try this little thing out I know I will

Ed 16v

Sorry to be the bearer of bad news but.... a Probe wont gain 35-40HP from a full exhaust system at all

I own a Probe 16, Probe 24 and a Euno Roadster and have all this tried and tested !!

Also yes it will gain you alot of HP max 15ish ona stock build... but it will lose you Torque due to the loss of back pressure and depending on what you are going for thats not always best........

The best of both worlds is to yes have headers and a cat back but stick in a hi/free flow cat which is the best option between torque and HP

I have my 16 Decatted but I wish I hadent now cause I have had to try and rebuild my torque curve again which aint fun

Its your car and your choice all im trying to do is allow you to make a more informed decision

Cheers

Roddimus Prime

yeah....not really much power to be made on through exhaust. Sounds like your friend is either a big liar or VERY uninformed.

for reference my 95 civic 1.5L had full header, 1 high flow race cat, and a mandrel bent 2.5" exhaust. I feel I may have gained 10hp but only on the top end, there is no lowend power to be had. good luck.

paulmp3

it must be a turbo probe.

macdaddyslomo

35-40 hp increase is still too high even for a turbo, plus headers are really an incorrect term on a turbo...maybe a tubular equal length turbo manifold...My brother in law has a 90 MX-6 GT(turbo)...he went with 3" cat-back and switched to a cone filter, total gain 20-25 hp....and please dont start the whole "backpressure" arguement again...backpressure is not beneficial, PERIOD!

Roddimus Prime

backpressure on a turbo car is not beneficial, you're correct. However a N/A car needs a certain amount of backpressure to produce torque. Example, my 1967 Mustang GTA came with a K-code 289 cobra jet engine, produced 271hp stock with cast iron exhaust manifolds, log-style, not well designed. I installed hedman long tube equallength headers, 3" mandrel bent piping, no cats, flowmaster 40series mufflers and 4" tips. The car slowed down so much it wouldn't even spin the tires anymore. I did manage about a 15-25mph increase in top end. It was a huge mistake! Be careful, Biger isnt always better!

macdaddyslomo

hate to always be correcting you Roddimus, but backpressure is NOT beneficial on NA engines either...the idea with exhaust on NA is to get maximum exhaust volume out of the engine while maintaining exhaust velocity...NA engines lose torque when the exhaust gets to big not because they lose backpressure, but because they lose exhaust velocity,which must be maintained in order to keep torque up...Usually on the best setup there is a little backpressure, but that isnt what keeps the torque up,its the exhaust velocity...usually the best setup is maximum volume and backpressure as close to zero as possible without llosing velocity....it's a common misconception though, because it WAS a widely believed idea....backpressure being beneficial is an old school idea and is incorrect though, notice the reference to an old 60's muscle car. Not trying to nit pick, but it IS the truth

Ed 16v

I understand where your coming from but how can you explain that if you took the headers off the car hardly moves as there is no back pressure at all ???

Not being silly just wanna hear your views im interested

Moving from my stock headers to racing changed alot by going from 4-1 ratio to 4-2-1 which released back pressure and my torque curve on the dyno showed this ?? it dropped in the low end

Torque is what gets the car moving and hp keeps it up there so as far as I can see on an NA car even de catting which releases back pressure damages your torque on a dyno ??

Please set my mind straight

Cheers


Ed

P.S. I like this forum theres no ******** just attacking each other its kinda cool for once

macdaddyslomo

Ed, please se my last post....If you remove the headers, exhaust velocity all but dissappears, plus that totally screws up flow and creates all kinds of air turbulance....the headers you put on were of poor design if your torque curve dropped out...a properly designed header does exactly what i said, increases exhaust volume without lowering velocity too much to affect torque

Roddimus Prime

The way I understand it you create the velocity by making sure the gasses aren't allowed to just float out the tailpipe instead of being constantly pushed out by the rythmic pulses of combustion. the exhaust gas must have constant force (slthough not a lot, just steady pressure) to keep velocity up. Having too big an exhaust system allows the gas to fill space out and each new blast of gas has no resistance until it hits the previous gas which will then create a "sliding cars on snowy roads" effect. One pulse has good speed, but bumps into the one in front. those pulses then slow down and bump into the pulse in front of it and so on. This damages the torque curve. By having a smaller (more restrictive exhaust it controlls the pulses and keeps a continuous stream of exhaust gasses flowing out of the car. this would in turn keep the gas velocity higher.

this is what I was describing earlier, I just didnt want to go into such detail.

macdaddyslomo

that is not what you were describing earlier if it was then back pressure is the wrong term.....sounded to me exactly like you were spouting old school muscle car tuner mentality....back pressure DOES NOT make torque..back pressure is a restriction of the exhaust gases that builds up because the engine is producing gas faster than the exhaust can expel it...ideal conditions in an engine is not to have " a little backpressure"...you said it like backpressure should be maintained, when it is quite the opposite...for optimal performance there should be as little backpressure as possible while maintaining exhaust velocity so as to not lose torque...backpressure is not a cause, its an effect...the reason why you can go bigger on turbo is because the intake charge is pressurized, so in turn the exhaust will be a higher pressure than an in an NA engine, there is such a thing as TOO BIG even on a turbo engine, its just that the exhaust pipes diameter on a conventional turbo engine would be rediculously big to reduce exhaust velocity

Protege_Joe

I guess my friend was BS'in me and he didnt know what he was talking about. I asked an import tuner shop about headers and a cat-back exhaust. He said If I bought Headers, and a muffler and took it to master muffler and had them build a 2 1/2 inch straight pipe from the cat."cat-back exhaust" he said it would bring me up 17-21 HP. so..ya sorry to misinform you guys thats the real scope

skr33t_rac3r

macdaddy is right ive been doing exhaust cutouts on old cars right after the header it gets the most hp and "torque" then ne exhaust diameters weve ever tried

maitai92

Protege_Joe,

I hate to say this but even w/ header,full catback and intake you will probably lucky to get close to 10whp in your 1.6. It takes alot to get 15-20whp especially on 1.6 that puts out about 70-75hp at the wheels. My 92 Miata that has i/h/e, shaved head,adj cam,advanced timing,recalib. AFM,freeflow cat was dynoed at 112whp from stock 96whp.