comments on exhaust sizing?

[turtleEK1]

yes yes this probably been covered, but i couldn't find anything that answered what i need to know- i got a d16y4... and i just purchased from egSi the gear for my new exhaust! high flow cat, res and muff! now the res and muff are 2.5inch, but i think 2.5inch exhaust piping would be too big!?

would having a 2.25inch piping that flanges to 2.5 at the res and muff create an issue with power and with noise?

replys would be apprecitated!

[Zdster]

What header are you planning on running. Personally I would be worried running a 2.5" (other than the cat that is) on a d16y4. I have seen power losses on a d16 with 2.25" however with a decent set of headers the response was very much improved.

[jun]

for a vtec dohc engine, 2.5" is a bit big
the recommonded size is 60mm (around 2.25"), a too big exhuast will result of lost of torque ...
but for a d16 engine ... i think it would be similar .. cox they r both na

[Zdster]

but for a d16 engine ... i think it would be similar .. cox they r both na

No, it is still way to big. 2.25" works alright as long as a decent set of headers are used (at least in my opinion). Anything more would start to really affect performance.

[turtleEK1]

i got 4-2-1 x force headers!

[Zdster]

With my limited knowledge, you would be going from a restricted to very wide open. It probably wouldnt be great, but I am not 100% sure. I guess taking it to a good exhaust shop and getting them to help would be the best bet.

[turtleEK1]

i do understand the 2.5inch is too big! just wondered if using 2.25inch that adapts to the 2.5inch resinator and muffler would work fine?

[Zdster]

i do understand the 2.5inch is too big! just wondered if using 2.25inch that adapts to the 2.5inch resinator and muffler would work fine?

When you say "work fine" what do you mean? No power loss?

You can attach the two together with a connecting piece so that wouldnt be a problem.

[turtleEK1]

When you say "work fine" what do you mean? No power loss?

You can attach the two together with a connecting piece so that wouldnt be a problem.

i mean that it not lose power (hopefully gain) and not be farty loud!

when you say connect the two together, do you mean from the cat is 2.25, then 2.5 into the resinator and then directly to the muffler without piping between?

[A.G.System]

Ok 2.25" on a civic is going to be loud no matter what.

And if you are planning on trumpeting that out to 2.5" cat etc you will have louder sections.

The ways to get around this is to either add another Resonator in the chain to dull some of the noise or change the size of the piping.

The D16y4 is a non VTEC SOHC engine so in reality anything over 2" is going to start to get loud.

Save yourself some cash and get a GOOD quality 2" system with 2" high flow cat . It will cost you more but the end gains for the system will be worth it.

I have a similar set up on my D16 but with an XForce muffler (2.5" in 4" out) and that makes the whole system have a nice rumble on idle but when opened up it gets LOUD :( .

[civicCXI]

have a similar set up on my D16 but with an XForce muffler (2.5" in 4" out) and that makes the whole system have a nice rumble on idle but when opened up it gets LOUD

I got similar setup, but with 2.5". It's loud when open u, I agree. I can feel power loss in bottom range.

I'm gonna change it to 2" system.

[defect]

I think 2.5" is too big for your block
Maybe 2" all the way would be best for your ride.

[Limbo]

Yes 2 " is best for a non-vtec, also i wouldn't go mix & matching the different sizes of the exhaust as you will affect the flow in the exhaust system, as the pipes would loose resistance in the larger openings but then restrict in the smaller ones. You want a nice consistent flow so that the pipe frequency helps to flow the exhaust out. That's why you will notice all the good brands are one specific size straigh thru. The only difference is in the extractors where they sometimes have a larger merge from teh primaries they will make a slightly larger pipe before going down to whatever the rest of the piping is.

BTW if you want not loud your gonna have to get a more restrictive exhaust, its the only way.

Put a 2" as your D sereis or you will loose all its bottom end power. D series make most of their power from bottom to mid. They are not as revvy as the B series so you gotta make the most of what you got. Unless you go turbo then its a new game altogether.

Also i would pay to get a good place to do the job so your not chopping & changing all the time due to bad worksmanship (experienced it before)

2 reasonators will keep the exhaust from being loud, or get a twinloop, even the xforce does a good job, better than a second reasonator.

[NogZ]

As limbo stated, 2-inch would be a perfect setup for your engine, will make it sound smooth, and nice power throughout the range. Maybe 2.25 is the largest you would go, to get a bit more top end.

The US peeps do believe that its better to have an exhaust system that gets bigger than smaller. I've followed that and have a 2.5 collector to muffler, thanks to my headers being 60mm at collector. WOuld have been interesting to see what 2.25 and 2.5 have done to the powerband, but thats $$ lol.

Good luck with your choice turtle :thumbsup:

[sivic]

you can use your 2.5" cat and muffler on a 2" system no probs. the place that does it wil just have to use some reducers. just make sure you get it done a good place or theres high potentioal for dodgey work for a job like that.
depending on the muffler design it may still be very loud without a resonator, even on a 2" system. just see how it goes then you can get a resi put in later if needed

[akira]

gotta admit ive got a 2.25' piping on my civic. ive heard that for a n/a 1.6litre car. u shouldnt go any bigger than 2.25' because any bigger than that will be just useless. 2.25' is the right size and it will produce better power over 2.5' because 2.5' will lose alot of power due to the fact that the piping is to big therefore air will take longer to get out. or something like that...

correct me if im wrong!

[kyle]

D series make most of their power from bottom to mid.
Then why do they make Peak power at around 6500Rpm....

[nugget666]

WHat about if you were after a cat back..

Just for a bit of a note.

would a 2' cat back be and sound alright?

[Limbo]

Kyle - That's Max power at 6,500 RPM.
If you make your exhaust too large your car at low rpm will take ages to get to the 6,500. You loose so much power low down. But if your that sure of yourself you can put it on and run it on a dyno. It will show you what happens when you put a very large exhaust on. Stock i believe is only 1 3/4", and rem honda spend alot of money to make sure you get power & economy. Note Type Rs come standard with 2 1/4, which is one of the best factory exhaust systems around. Are you expecting your engine to make more power than a Type R?

Have a look at the expensive exhausts, they do not go over 2 1/4 for a 1.6ltr. And even then they are looking at cars which have alot of work on them.

Nugget - Yeah 2" Cat back and it will still be loud. Hondas are loud by nature. Only way out is 2 reasonators or a twinloop exhaust.

Guys i've had 4 exhausts on a 20v Corolla & 4 sets of headers on my EK4 with 3 different mufflers. Its been through like 5-6 different combos and that's only cos my friend owns an exhaust shop and i get work done cheap. That been said i've wasted more than $3k on exhaust trying to get more power. There is a limit to how much power you can get from an exhaust system.

If your after a good system for your D series here's what i would recommend.(you don't have to take my advice)
Headers (rep brand. Mandrel bent equal length, ceramic coated if you can afford or wrapped), 2" mandreal bent system, Hi-flow cat (large body or a steel cat if you can afford it), at least one reasonator & a straigth thru muffler.

If you want it quiet then your gonna have to compromise on the performance, add an extra reasonator, or get a twinloop muffler/restrictive muffler.

[kyle]

On my old D16y8(R.I.P) I had Intake/Header Stock Piping and Muffler and I achived 112.6Whp. After Upgrading the intermediate piping with 2.25" I gained 1Hp making 113.9Whp, loosing only 1Whp under 85Km/h in 4th. Not really as mamoth loss in power as you make it to be.

Furthur more, when racing when are you ever doing less than 85Km/h in 4th, when at redline you usually change into 4th at approx 140Km/h.

Ill post my dyno read out when I find my Cam.

[Nuttz]

rep +1 there :) :thumbsup: Limbo

i got a 2.25 catback on my d16 and i did notice a little loss in bottom end and little gain in topend.

[sivic]

actually, most expensive (read: japanese) companies do go over 2 1/4 for 1.6l NA. systems made for B16's are 60mm which is a bit over 2.3". however, this is the internal diameter of the piping.
over here piping is usually measured from the outer diameter. so therefore when you take into account the added diameter of the actual piping on a 60mm system it turns out to be VERY close to a 2.5" system.
basically the 60mm systems from all the various jap tuning companies are the same size as a locally made 2.5" exhaust.