I have an invidia n1 exhaust muffler on stock piping, i was planning on going to a muffler shop and getting my catback piping in 2.5", and my down tube for my headers in 2", would these measurements be correct for my 95 st??? thank you, i need to know, i also have stock headers right now,

Wondering the same myself. Was planning on having exhaust redone from behind the second O2 senor and back. Remove cat, resonator, and stock muffler and stay with the stock 2" diameter and put a Magnaflow muffler on. Provided aren't going to do excessive modding to the engine I'd think 2" would be enough. I'm personally afraid of going too big, and having a bad sound. Hopefully someone that's been there and done that, can chime in.

2.25" max

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agreed especially on such a low ouput hp engine above 200hp i'd then go with 2.36"

This post has been edited by BonzaiCelica: Oct 27, 2013 - 9:27 PM

Thanks for the info everyone! 2" it is!

My dd 95 corolla has the 7afe with intake and obx header and i did all the piping from the header to the muffler 2.5 and the car moves great and sound's fantastic.

Celica SS-III and Integra Type R DC2 both have 57mm exhaust piping.

i'd still go with 2.25

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I wouldnt remove your cat, its pointless your not putting out the power that requires a cat removal. A resonator doesn't restrict anything it just reduces exhaust noise.

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It's the mod effect that you think the car is faster but it's not really. You cant feel or notice a hp gain from an exhaust because all you're doing is freeing up the path, you're not intaking more air, which means you're not pushing anymore out.

A car works like a vacuum, you have X amount coming in and X amount coming out, it doesn't matter how large the path is you can only push out as much as you're taking in.

This post has been edited by hatchy_gt-s: Apr 6, 2012 - 1:49 PM

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It's the secondary cat. Everything behind the first cat and O2 sensors I want to replace. Doesn't cost that much more than just adding a muffler at my local exhaust shop. So, figured what the Hell, might as well. Plus I'll make money from scrapping the cat.

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Well, i personally feel the car more light and nimble than before. I know i gain almost nothing of hp but i don't feel the car being held back as much which is what everyone has told would happen with this setup including my mechanic whom i've known for 12 years.

I have a question, our current exhaust pipes go over the rear axle and bend like 3 times, is it a good idea to just have a straight pipe go under the axle and straight to the muffler

basic concept, is straighter pipe is better straight flow, some aftermarket exhaust don't follow OEM pipe paths and try to straighten it out as much as possible. a good example i saw was on a 240sx. early 90s

This post has been edited by trdproven: Apr 8, 2012 - 5:31 PM

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Asom! Im doing it then, plus it'll have about 1 foot of less exhaust travel so itll probably be louder, thanx man

only thing is look at clearance and how low it hangs if its good with you.

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Im sorry I should have been more clear I was talking the diff between a 2in(recommended) exhaust and a 2.5in. Yes, the car will have more response when changing from stock because you in crease the air flow.

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A lot of people are running under axle exhaust setups and have no issues. I've seen several 3s swapped cars rocking 3" under axle and don't ever have clearance issues. (lowered cars at that)

I'm lowered on Tein coilovers, and I think I'm as low as I can go before I start to bottom out on the front or have clearance issues with my wheels tires ( 16x8 ET35 ) piping is ran under the rear subframe and I have no issues of exhaust hitting or anything like that. I do want to change it to go over, but that's because I hate how it looks, I want my exhaust to look more facotry. but no issues at all.

that's a 3in diameter piping.

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The key here is to not go too big. One of the most important functions of the exhaust is to suck air out of the cylinder. Too small and the exhaust creates backpressure which is bad but a small exhaust also creates high velocity airflow which is good. Too large an exhaust creates minimal backpressure which is good but also lowers the speed the exhaust travels through the pipes, which is bad.
Headers will give you the greatest performance boost because the pulses of exhaust gas will actually create a low pressure vacuum on the exhaust valves and thus help increase the flow of your cylinder head

The trick to the full exhaust system will be to find a pipe diameter that has the best balance of low backpressure vs high velocity flow. This is why minimizing the amount of bends and using mandrel bent tubing is so important because they will kill your exhaust's potential to help make power. Look into straightflow mufflers too, stock mufflers with all their baffles inside create some backpressure.

One last tidbit I'll leave you with is that your entire exhaust system is tuned to a specific frequency. The headers/manifold will have a specific harmonic(of exhaust pulses) they are tuned to based on primary pipe length and diameter. Also the muffler will be built with a specific rpm in mind which will be affected by how many cylinders are feeding it. You should do research on exhaust components before you buy them to determine what rpms they will be most effective at in regards to performance and noise reduction. (maybe highway speed is where you want maximum effectiveness at, or maybe close to redline. Its up to you.)

^ Ya for a street car you dont need any of that. A larger pipe with a hi flow muffler is all you need. If you want 2 build a race car then yes you should do the research.

Or if s/he has a solid plan to go turbo within the life span of the exhaust.. ex: i have a 95 ST and am in the process of making a 2.5" exhaust for it.. there are a few strategies that i am employing in my design.. but this exhaust will last me till after i go turbo, and just before i implement my last phase of my plan for this car..

i guess what im saying is that the questions you are asking are good ones but the main one you need to ask your self is what do i REALLY want to do with this car. that will dictate what is or is not good for your application.

I would just go 2.25" piping and follow the OEM paths, simple. IDK about 2" because I think the stock is 1.75" so its not much of a difference to burden yourself for a .25 "upgrade". Plus the greddy sp2 makes the exhaust that is also for the ST, and thats about 2.36~ so in the middle 2.25 is good already.

2.5" is just ridiculous for an ST, don't even think about this.

This post has been edited by trdproven: Apr 9, 2012 - 6:03 PM

Well today I went to go do my exhaust, I replaced all the axleback piping with 2 1/4" piping, I went under the axle cause theres enough clearance, looks great, souds way better, ill try uploading a link to the vid here soon

2.5 is larger than stock for half of chevy 350s, and they are 5.7L
Too big will ruin performance and probably throttle response


This post has been edited by Special_Edy: Apr 9, 2012 - 6:16 PM

I agree with you on the 2.5, which is good for turbo already. but i did at one point run a 2.5" 5zigen catback and it wasn't that bad really. I thought it would be bad. But the 2.5 works ok on 3rd gear especially and then up. But i prefer the Greddy SP2 of course. Still so, wouldnt go back to 2.5 though, wouldn't recommend it, but the 2.25 is okay for him nothing bigger.

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Powerband feels different when you drive? Headers, downpipe, piping size, intake air filters, resonator, and muffler combination will give you your final sound.

This post has been edited by trdproven: Apr 10, 2012 - 2:08 AM

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A number of things play into exhuast design, not simply a diameter. Design efficiency as a complete system is very important, material selection, beyond this there are mechanical and ancilary attributes that contribute to the values that equate the ultimate formula. Again, what is desirible for race car is not pragmatic for road car. The area in which engine speeds
are operated at play a fact.

You have a 1995 ST, so I'll assume you have a 7AFE and not swapped anything. I can tell you that very few firms have dynos deticated behind systems
for the 7AFE. How response and power is created is very important. Remember the factory management is fairly crude, and is not capable of making major adjustments.

I would need more information about what you are trying to achieve to give you a professional opinion. A number of factors and a dollar to power ratio.
Is this merely a replacement, or is this for something special or you have specific areas of interest that need fine tailoring?

Regards,
Mick

revival ha. ok so anyone have experience with IS300 or SS-III 3sge Beams OEM Exhaust muffler. are they true 57mm going into the muffler. I know on GT Celica's the muffler tappers down from 2 inches to 1.5 inches going into the muffler. is this the same for IS and Beams?

IS300 is a 2JZ-GE

yes i know i read is300 and rs200 (5th gen beams that came in japan RS200) use 57mm piping. im trying to find the thread now on beams owners group mr2 board section but can't.

one guy said this on beams forum from mr2 board I'm using a standard Altezza rear muffler, and a fibreglass packed one about half way down the car.
Altezza muffler is quite a cool design, it's got a spring loaded flap so that when enough gas flows through to open it, it bypasses a few of the chambers.
So nice and quiet(ish) while cruising and the flap is shut, then when you've got your foot up it, it minimises restrictionrs
is this true? even for the is300 muffler.... aah found source but pics are dead. http://my.is/forums/f87/ever-wonder-why-st...rictive-113759/

sound of stock rs200 exhaust
http://www.youtube.com/watch?v=w8uhYdaurTE

This post has been edited by BonzaiCelica: Oct 28, 2013 - 12:15 AM