exhaust backpressure?

[scuba_sean]

ok, i know the ka24e needs a bit of backpressure to operate optimally before you add cams. i wanna take my pipe from where the cat attaches on to the front pipe, and go back to a magnaflow muffler. if i keep the stock manifild, will this be good? also, im planning on puling my cat tomorrow. i heard that as long as you replace it with straight pipe, you do good and not harm. is this true?

[b240]

Im not making sense out of this? Are you getting new piping from the cat-back? Or are you just putting in a test pipe which is a "straight pipe" and running your stock piping? The only thing you really need to worry about with the test pipe is that it may be illegal in your area. I dont know what the canadian laws are like , but here in california there ****ing strict.

[scuba_sean]

ya, cause cali has a layer of smog a mile thick. we dont do emissions testing here. i wanna take the cat out, and then go from there back to the muffler. i think that is a test pipe

[b240]

so you mean you want to put test and custom piping in with a mag muffler?

[b240]

heh that post came out all fuc|<ed up

[scuba_sean]

precisely. but tomo im just puttin the test in

[b240]

Be careful not to break any bolts or strip them. I did with one and had to make a extra trip to autozone for another bolt. There is also a ground wire that is attached to the cat from the chassis. Keep that intact when putting in the test pipe.

Everything should be good. Good luck.

And you are going to have to get new gaskets for the test pipe as well , because the cat's old gaskets will be fuc|<ed. =]

[scuba_sean]

i bet. my friend is a welder, and hes making me more flanges and were gonna weld the test pipe in place. were doin at at my dads shop, so the bolt thing isnt a prob, and can i use like cork or something to make gaskets?

[Bandit240]

Cork??? Hell no it would burn up in not time at all. Just go to a local auto parts store. I got both gaskets for my S-13 for all of $6. Right now my car has a gutted cat with just the resanotor, the muffler broke off (with some help) so i attached a peice of pipe to run out the back. Sounds great untill about 5000rpms then your ears start to bleed(j/k but its loud as hell)

[scuba_sean]

so you kept the resonator and lost the muffler????? thats ****ed up. can you notice an increase in power?? and is it noticeable looking? (my parents are controlling and the give me a place to live!)

[Bandit240]

Yea its very noticeable. Thats why i did it. My granddad is the kind if its not broken dont fix it. So i broke it so we could fix it with a after market cat back system. There is an increse in top end but it lost some low end. Toped out at 124 today when i couldnt get more than 122 out of her before.

[scuba_sean]

well i like the low end of the the ka24e, but does it lower your 1/4 time?

[Bandit240]

Ohh 1/4, sorry the 240 has never touched the track. I will be driving a 68 Nova that runs 7.91 on the 1/8 next week.

[scuba_sean]

well overall, do you think it would be a good mod? i mean i like drag racing, but i wanna try autocrossing. i just love the low end torque of the 240, its so nice.

[daniel240]

I did almost the same thing you are doing. First i had pipes ran from the cat back taking out the resonator to a straight through Magnaflow muffler. Later i got the HS header which eliminated the first cat. I still had plenty of backpressure. later i took off the second cat. this really didnt do anything. i dont think i gained or lost anything but its started backfireing a little so i got a small silencer put on and this solved the backfiring prob. this setup is working great

[scuba_sean]

well you see, the problem is im a poor bugger. i really cant affoard a magnaflow right now, unless i find another car with one and i have a hacksaw in my pocket anyhoo, im thinkin of takin out the cat and the resonator for now, and getting a magnaflow when i get money.

[daniel240]

yea, doing that will free up a little hp and make your car a little bit louder

[scuba_sean]

well i did that today. i took off the cat, and i had to grind off 2 of the bolts! anyway, we took off the cat, and the resonator, and put in the pieces of straight pipe, (jacked from a local muffler shop's dumpster!) where they were. we ran out of time, so all we have to do now is bolt it on and re-attach the hangers. i wanna start it up, but cant cause my transmission and starter are off. i think when they are put on, i think im gonna notice a big difference, cause i did the exhaust, im making headlight vents, putting royal purple MaxGear in the transmission, and puttin in onw of those resistor things in where the IAT sensor is