quarter of an inch, that much better? (exhaust)

[Cold Fusion]

i got a 2 1/4 inch exaughst on my teg at the moment with a hi flo cat, restinator and a hi-flo muffler, would i see any gains if i changed it to 2.5, no resinator and a cannon at the end instead of a muffler? or is it just throwing money away, OR would i see an improvement if i just took out the resinator and muffler and put in a cannon?

THanks

[Cold Fusion]

sorry wrong section, can somsone move it to all motor?

[FR33K]

ull probably lose power

[aaronng]

Moved... and it's exhaust, ;)

[Cold Fusion]

ull probably lose power

im installing stage 2 cams, greedy emanage, got the air intake and stuff, so i think i would need bigger because of the more air/fuel going into each cylinder...or am i miss informed?

[dudeling7]

i was reading on team integra - you should check it out its got everything you want to know about integras. but a 2.25 system should be good for up to 200hp if you are planning on going over that then go ahead with a 2.5 inch system.

[Slow96GSR]

Actually 2.5" is a good size for Teg's with mods. It's what I have and it was a great choice. I've seen some with larger and some with smaller but most of them say they want something different. Most people with the 3" want smaller. Good luck.

[dsp26]

2.25in = 57.15mm
2.50in = 63.50mm

2.25
A=3.14159... x 57.15mm
A=3.14159... x 28.575 x 28.575
A=2565.21mm^2
A=~25.65cm^2

2.50
A=3.14159... x 63.5mm
A=3.14159... x 31.75 x 31.75
A=3166.92mm^2
A=~31.67cm^2

Surface area difference (when looked at circularly)
31.67 - 25.65
=6.02cm^2

now that seems small.. but think of it as a cylinder (your exhaust pipes) and multiply both surface area values by the length and the volume difference is massive!!!

I agree with Slow96GSR about 2.5' mandrels!!! i wouldn't be worried about backpressure/bottom end loss with a vtec and a big exhaust pipe.

I also don't understand regardless what car/engine why people ALWAYS suggest 2.25 press bent... WTF?!?! most say budget issue.... but when it comes to performance, remember that you want power and exhaust systems are one of those things you don't want to have to redo twice!!!

a 2.5in catback was my first ever mod on my stock sr20... yeah sure i lost plenty of bottom end for a marginal gain in top end.. but i planned ahead and know what work i will be doing tot he engine.

If you want an exhaust system now, think carefully about what your going to do later in advance....

Search Keywords: Exhaust Size, Pipe Size, Mandrel Bent, Press Bent, Exhaust Flow, Catback, 2.25, 2.5, exhaust, exhaust system,

[sivic]

I agree with Slow96GSR about 2.5' mandrels!!! i wouldn't be worried about backpressure/bottom end loss with a vtec and a big exhaust pipe.



its a DA - B18A. no vtec. but yeah 2.5 would prob be good once cams etc go in

[SLOWEGG]

I run 2.5" on my B16A, seriously it feels better then 2.25. My friend has same the car and engine and it feels abit.. "chokey" And its still very driveable even with the loss of back pressure.

But you have 1.8L so i would agree with Slow96GSR aswell.

[ACTI0NMAN-1]

i went with 2.25" on my b18a but with press bends, so it dropped in bent areas to 2.00".

[marcus]

gosh this is confusing i went to an exhaust shop and that mechanic keep recommending me 2.25 pipes from catback ....so which is better? mine has a 4-1 header install.

[Slow96GSR]

Get what you want, screw what they say, they're not paying for it. Get the 2.5" mandrel bend system. If you have to order one then you can run it to some serious money but the gains down the road will make it worth the money spent now. If you want the 2.25" then get that. There are plenty of manufactures of great/good exhaust systems if a shop won't/can't do what you need/want. Good luck and remember it's you car, your money, and your decisions.

[dsp26]

well since its a general concensus that
4-1 = Top End
4-2-1 = All-Round

For you i'd get the 2.5in mandrel... but yeah its upto you what you want... vtec or not, as you said.. you MAY get cams later.....

if you don't go heavy on NA mods then get a cannon and put the silencer on... i scavenged some noticeable backpressure on my fully stock engine at the time when i got the catback.

and thats right, screw what exhaust shops say... they work on sooo many different cars with just exhaust mods that they dont actually consider other mods to the engine....

liverpool exhaust insisted on 2.25 press and i explained what plans i had to warrant the 2.5 mandrel... all the guy said was "..oh..."

[Cold Fusion]

i will have the cams on like 3 days after the new exaughst is put on. wiht 4-2-1 headers as well, and a greedy emanage (as in my sig) but im still not sure, i kno its my money and my everyhting but id like to kno, coz i dont wanna waste another 400 bucks on something that might sound shitter and make my car slower!

[dsp26]

i don't know the cam specs... since it ain't a vtec cam your in my boat. what power band are they designed for ignoring the fact you can change the band with cam gears?

but if their fairly agro cams in dur/lift anyway get the 2.5mandrel... cams GENERALLY allow more air/fuel mixture in the cylinders per cycle hence why they create power.... you will need a big exhaust.

in terms of extractors, this is a good explanation of "scavenging effect":

You don't need backpressure unless you have overlapping cams.

The reason why we don't slap on 4" exhausts is because we need gas momentum to create VACUUM* - the opposite of back pressure. Vacuum created after one exhaust pulse, aids in the clearing of the cylinder of the next pulse.

*(By Vacuum, I don't literally mean an absence of gas, but just an area of much lower pressure than the gas in the cylinder and the gas in the rest of the pipe)

[marcus]

well since its a general concensus that
4-1 = Top End
4-2-1 = All-Round

For you i'd get the 2.5in mandrel... but yeah its upto you what you want... vtec or not, as you said.. you MAY get cams later.....

if you don't go heavy on NA mods then get a cannon and put the silencer on... i scavenged some noticeable backpressure on my fully stock engine at the time when i got the catback.

and thats right, screw what exhaust shops say... they work on sooo many different cars with just exhaust mods that they dont actually consider other mods to the engine....

liverpool exhaust insisted on 2.25 press and i explained what plans i had to warrant the 2.5 mandrel... all the guy said was "..oh..."


gosh hw come exhaust shops always insist in 2.25??me too i went to one shop and they keep pushing me for 2.25 when i want 2.5

[SKREMN]

i had 2.25 on my car with the b18a and now got 2.5" with my b20 the car was great with the 2.25 didnt have internals only reco and bolt ons
put your car on the dyno and see how it runs your tunner shoudl be able to tell you then if it requiers a bigger exhaust

[dsp26]

^^^not really unless you had both catbacks on hand and flanged to test both on the dyno for power.

you would need the tool some performance shops have to measure inlet and outlet manifold pressure to determine if it warrants one....

[dsp26]

gosh hw come exhaust shops always insist in 2.25??me too i went to one shop and they keep pushing me for 2.25 when i want 2.5

looool!!! mate... exhaust and suspension shops and basic mechanic shops like to do their own thing unless you clearly specify to them on a tombstone engraving what you want.

i've always wondered what wheel alignment suspension shops do on a stock car apart from toe adjustment when not many cars come with adjustable camber??

i've always wondered what "tuning" mechanics do to stock cars that have a rom based ecu... i don't understand how changing plugs/fluids.. etc is even considered "tuning/tune-up"

[SKREMN]

by adjusting the timing on the exhaust cam you can get an indication of whats happening to the flow and if more is needed or not

[Cold Fusion]

the sale of my current fell through so i dont think i can even afford 2.5 anywahy, but im gonna take out the muffler and put in a cannon on the end for a presumed better flow.

ill let you all kno what happens :)

[marcus]

is 2.25 or 2.5 better wif a 4-1 header

[locote]

Kallan i got a 2.5 in my teg but its not mandrel bent but ur quite welcome to do a swap with me if u like as id like a quiter exhaust for my car since im selling it.

[Limbo]

the noise will all depend on the quality of your muffler & reasonator.
the extra 1/4 inch will help you top end, an a canon has less restriction so you will get better performance with the added noise.

Just rem you gonna have a trade-off somewhere as the quieter you go the more restrictive. If you want max power then you gotta learn to live with the noise and the police harrassment.

more power = more $$$

no real way around it.

[Limbo]

p.s do it right the first time and you won't spend more money doing it a second time.

[dsp26]

noise polution solution :D :thumbsup:
http://www.gccorp.com.au/automotive/product_info.php?products_id=216

hehehe