Customizing'it!

hey over the next few weeks ill be going to some exhaust shops to get some ideas and quotes on an exhaust system for my DC4.

I wanted to get a custom made one because im one of those fuss pots that wants an exact size, noise and length (gee sound like a girl =P) plus its probz easier then buying a 2nd hand one n trying to make sure it fits, its in working condition etc.

basically want an exhaust that will give me good airflow, not loud but some sort of signifant noise beta from stock.

Wanted to know what things i should look out for or ask my exhaust shop when customizing my piping, sizes, mufflers etc.

Please let me know if anyone has made their own customized exhaust, tips and thoughts of what i shld be talkin abt with mechanic and advice if any.

1. Make Sure its mandrel bent when u ask for a quote...
2. Check to see if they screwed u over by not using mandrel bends BEFORE u pay..
3. Inspect the car while its up on the hoist.. a good reputable workshop should let you do this
4. Don't go to Non-Exhaust places to do.. (they WILL mess up the job bad... e.g. Wheel Places offering exhaust fitting...

Note that custom exhaust don't fetch as high a resale value as a aftermarket JDM one.. if the quote for the catback is in the region of 600++ i HIGHLY recommend getting a JDM one..

Cheers
Hope This Helps

i quoted 1200 for my exhaust system at westside mufflers. but i neva got it put on cos i went broke.lol
it was suppose to be from the headers into a high flow cat and through some wide pipes and as straight as can be. then coming out of a twinloop cos the guy said it would be quiet....

i just bought a catback system for my car. i had some really loud one on and i wanted to change and went to the wreckers and got one off a type-R. Ive never heard of the brand its called JUN B.L written on the muffler and little bits of the piping. Is it anygood?

its a korean brand. think it used to do quite well in japan.

JUN B.L the last time i remembered. all the high powered turbo cars in jap used them. esp the supra's.
u could google them for images of cars.lol

damn lol. i must of hit jackpot lol. the wrecker thought it was a stock dc2R exhaust. Ive installed it and its got a really nice sound to it and the car feels much more torquey.

gsi_psi you got luckyyy!

wow thats a pretty good idea. i shall look into wreckers and see if there is anything there!

Quote:

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Originally Posted by squish85

1. Make Sure its mandrel bent when u ask for a quote...
2. Check to see if they screwed u over by not using mandrel bends BEFORE u pay..
3. Inspect the car while its up on the hoist.. a good reputable workshop should let you do this
4. Don't go to Non-Exhaust places to do.. (they WILL mess up the job bad... e.g. Wheel Places offering exhaust fitting...

Note that custom exhaust don't fetch as high a resale value as a aftermarket JDM one.. if the quote for the catback is in the region of 600++ i HIGHLY recommend getting a JDM one..

Cheers
Hope This Helps

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don't mandrel bent systems cost a fortune and i know theyre better but its not a big turbo track car its a dc4

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Originally Posted by rbk_212

don't mandrel bent systems cost a fortune and i know theyre better but its not a big turbo track car its a dc4

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Not a fortune... There is no point of getting a NON-mandrel bent exhaust (Catback). You'll be downgrading, as the diameter of the bends will be smaller than stock, and then you have a whole bunch of restriction. It's just plain stupidity.

yeah mandrell ftw and pretty much all good exhaust shops only do mandrell now... i rekon a decent catback at a reputable workshop will set u back between $800-1000, if ur payin less than that i dnt think its gna b of the best quality.

... and yeah jun.bl is a good brand very popular even flicking through performance mags, really popular 4 mufflers at good exhaust shops.

I never knew non-mandrel bent exhausts existed. I want to open an exhaust shop now, and just find random pipes and bend them with my foot, and bolt them up to cars - Rip people off, haha.

^ its called a press bent system, most exhausts you see on street cars are like this

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Originally Posted by rbk_212

^ its called a press bent system, most exhausts you see on street cars are like this

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No they aren't...

Edit: I have looked at our 5 family cars, and some cars on the street... all the stock systems are all mandrel bent. Only crappy exhaust systems are press bent. If stock exhausts aren't press bent... why decrease performance and get one made?

stock dc2r exhaust isnt mandrell, im no exhaust speciallist but u wont find too many non-modern cars that hav mandrell exhausts

There are some places that litrally bend it, so that the corners of the crease in the metal are pointy, and the bent is really flat. I have seen some really bad examples of that. But googling it now, if you want to get technical, Normal (I'm assuming Press) bent is like this:

http://www.jimscustomexhaust.com/images/badbend.jpg

Here is a pic of a mate exhaust we pulled off (Was worse in other places, but this is the only pic I have):

http://img370.imageshack.us/img370/6329/loltr1.jpg

Mandrel:

http://www.jimscustomexhaust.com/images/good90.jpg

So that means my Buddyclub exhaust wasn't even mandrel bent properly?

"all stock systems are mandrel bent" is a very big generalisation, most cars have a press bent system and i was specifically referring to aftermarket exhausts that people fit, as most catbacks are installed for the noise not for performance (performance gains from a catback are the subject of some debate any way)

when most people get a catback they get larger diameter piping so even though the bends arent as good as mandrel's they are still better flowing than the stock system which is usually press bent anyway

i know mandrel is better but some people cant justify it for the price they have to pay

How much more is Mendrel bent than press bent?

It's worse to go from a mandrel to press bent system, regardless of piping diameter. I have asked the question to a few japanese companies when I first got my car, as I didn't have a clue what an exhaust system even was, and didn't even know forums existed, lol.
Reason being as exhaust gases go to a larger diameter to a smaller one... being at the bend makes it worse as there is backflow of gas. It technically restricts the gases flow more than a smaller mandrel bent system. Also, catbacks do add power. So many systems have been dyno proven to gain 7-11ish kW's ATW. Felix's DC2R on CITR is one example, and Justin fox on his S2K.
A muffler alone however will not do much with out opening up the b-pipe.

Why change an exhaust for noise? I wish I had a quiet car...

One thing about catback systems is from i learnt. If its got a brand then expect gains, otherwise dont expect much. I went from a drift (autobarn crap) catback to a jun.b.l exhaust leading to toda power 4-2-1 extractors and there is big difference in accelleration and topend.

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Originally Posted by GSi_PSi

One thing about catback systems is from i learnt. If its got a brand then expect gains, otherwise dont expect much. I went from a drift (autobarn crap) catback to a jun.b.l exhaust leading to toda power 4-2-1 extractors and there is big difference in accelleration and topend.

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Not always true in relation to a catback... well b-pipe anyways. Headers, yes. It's important that you have a well designed header, and will notice gains. You might notice sliigghhttt differennces in response with different axel backs (muffler).
The only difference you'll see with different branded catbacks is the resignator (a pipe if a pipe after all, as long as it follows the straightest line possible on the underbody). I had a long chat to the head of J's Racing when he was here in Oz, about the J's exhaust as I had just bought one at the time, and told him I had noticed quite a large gain compared to the Spoon exhaust. He explained that there was a great deal of engineering in resignator technology, ie: where a resignator is placed on a B-pipe, different mid resignator and muffler resignator size combinations and what materials are in a resignator. Hence the price tag of the J's exhaust (It's also Ti)

But he said... end of the day, an exhaust with no resignator is the best for gains. But Japanese companies have to satify consumers, and make the sound of the exhaust bareable for occasional weekend racers that drive their cars on the street.

But yes, if you're not after that extra bit of power and response, a custom 60mm (i'm talking about a DC2R here) mandrel bent b-pipe with a resignator (if you wanted one) slapped anywhere along it will yield sufficient gains, with a good headers.

Mugen Twin Loop for the win !!!

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Originally Posted by VTECMACHINE

How much more is Mendrel bent than press bent?

It's worse to go from a mandrel to press bent system, regardless of piping diameter. I have asked the question to a few japanese companies when I first got my car, as I didn't have a clue what an exhaust system even was, and didn't even know forums existed, lol.
Reason being as exhaust gases go to a larger diameter to a smaller one... being at the bend makes it worse as there is backflow of gas. It technically restricts the gases flow more than a smaller mandrel bent system. Also, catbacks do add power. So many systems have been dyno proven to gain 7-11ish kW's ATW. Felix's DC2R on CITR is one example, and Justin fox on his S2K.
A muffler alone however will not do much with out opening up the b-pipe.

Why change an exhaust for noise? I wish I had a quiet car...

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Quote:

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Originally Posted by VTECMACHINE

How much more is Mendrel bent than press bent?

It's worse to go from a mandrel to press bent system, regardless of piping diameter. I have asked the question to a few japanese companies when I first got my car, as I didn't have a clue what an exhaust system even was, and didn't even know forums existed, lol.
Reason being as exhaust gases go to a larger diameter to a smaller one... being at the bend makes it worse as there is backflow of gas. It technically restricts the gases flow more than a smaller mandrel bent system. Also, catbacks do add power. So many systems have been dyno proven to gain 7-11ish kW's ATW. Felix's DC2R on CITR is one example, and Justin fox on his S2K.
A muffler alone however will not do much with out opening up the b-pipe.

Why change an exhaust for noise? I wish I had a quiet car...

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well a press bent catback can be like 450 and a mandrel can be 900 and upwards depending.

hah yes i too wish my car was quiet i only meant to point out that alot of people with "zorsts" only get them for noise, they arent really performances enthusiasts obviously.. :p

also 10ish kw ATW is brilliant they must have been some really good systems, a generic systems probably wont be getting that sort of gain

dammit i wish i had a mandrel bent system now, i got my catback done when i was 17 and didnt have a clue... lol tell me, can i just get the B-pipe changed in future to a mandrel?
coz i already have a good muffler, stainless x-force extractors and a hi-flo cat

Go out and buy a Vision B-pipe. They make the Spoon ones, but are half the price. Or yes, you can go get a new b-pipe made up which in mandrel bent.

A custom exhaust can yield the same gains as an expensive JDM exhaust. Like I have said, only difference is resignator technology.

Anyways, don't worry yourself about peak power, cos it doesn't mean much unless you drag race alot. Also don't take dyno results seriously. A dyno is a tuning tool, and different dynos read very differently. An exhaust gives slight power/torque and more response throughout the rev range - well, a mandrel bent pipe anyways. Press bent, i don't think you'll notice a difference from stock, or maybe even a decrease in performance even, as there is a heaps of restriction which screws with response.

Also I wouldn't say Xforce headers are "good". They normally leak where they press against the block. Design... Meh. But for a DC4 (that's what you have right?) xforce headers are OK. Also if you have a DC4, don't be expecting 10kw gains.

yeah im aware of that, i want driveability and torque not massive dyno numbers

and honestly, the car felt better after i had a press bent catback, and got heaps better after the extractors and cat were changed, maybe i was just imagining but it felt freer (i have a dc2 not a dc2r btw so my system was probly more restrictive)

also it depends how badly the system is bent..

additionally, do resonators (not spelt resignator by the way) make much difference to performance, i thought they only changed the note and weren't very restrictive?

Quote:

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Originally Posted by rbk_212

yeah im aware of that, i want driveability and torque not massive dyno numbers

and honestly, the car felt better after i had a press bent catback, and got heaps better after the extractors and cat were changed, maybe i was just imagining but it felt freer (i have a dc2 not a dc2r btw so my system was probly more restrictive)

also it depends how badly the system is bent..

additionally, do resonators (not spelt resignator by the way) make much difference to performance, i thought they only changed the note and weren't very restrictive?

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Resonators (sorry if I spelt it wrong) do restrict a little, as is slows the speed of the exhaust gases. They are there only to decrease exhaust noise. So no resonator, is better than having one. But for a street exhaust, a resonator is benficial for EPA and defect reasons.

The custom drift exhaust mandel bent catback i had , with no resonator or hotdog and the gains werent greater than my new exhaust.

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Originally Posted by GSi_PSi

The custom drift exhaust mandel bent catback i had , with no resonator or hotdog and the gains werent greater than my new exhaust.

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Dyno sheets please. What temp was either day?
Was the piping diameter the same? Some exhaust shops will use 2 1/4 inch piping, where as Jap systems use 60mm (I think 2.38 inch) pipes. There is a lot of difference.

just a quik example of cat-backs making a good difference... was at a dyno day recently i cant remember the exact numbers, but there were 2 practically stock S2K's, as far as i rememeber both had induction, but 1 had cat back, other 1 didnt... the S2K with cat back pulled 149atw while the other only managed 130ish from memory.

You can't really compare 2 different cars. There are so many other factors you have to take into consideration. Sure the exhaust did make a huge difference though.

yeah thats wat im saying... 2 same cars of similar age with the only main differece the exhaust... no way in hell 1 can pull 20kw more on the same dyno, even if the exhaust didnt make 20kw difference it certainly made a fair chunk of it.

pay for my dyno's ill go do it lol :p jkss

but yehh power delivery is a lot greater with new exhaust.

the drift exhaust piping was smaller though but not by much.. I can take photo comparing em if u like...

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Originally Posted by GSi_PSi

pay for my dyno's ill go do it lol :p jkss

but yehh power delivery is a lot greater with new exhaust.

the drift exhaust piping was smaller though but not by much.. I can take photo comparing em if u like...

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Nah, that's cool. The fact that you don't have dyno sheets, and the two are compared at different times of the year doesn't prove anything. If the sound is different, it will create an illusion that you have more power. If piping diameter has changed.. that's also very different too.

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Originally Posted by VTECMACHINE

Nah, that's cool. The fact that you don't have dyno sheets, and the two are compared at different times of the year doesn't prove anything. If the sound is different, it will create an illusion that you have more power. If piping diameter has changed.. that's also very different too.

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if u were referring 2 my comment, the cars were dyno'd on the same rollers within maybe half an hour of each other

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Originally Posted by Tegzieboi_BAR

if u were referring 2 my comment, the cars were dyno'd on the same rollers within maybe half an hour of each other

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Sorry... was reffering to GSI_PSI's post.

Exhaust is the way 2 gooooo

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Originally Posted by squish85

Mugen Twin Loop for the win !!!

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i dunno about that..when i went to the exhaust shop one of the mechanics said the twin loops lose power as the gases goes through the resonator twice to reduce the noise... the overall effect is it will be quiet in cruising and loud in vtec but giving a loss of power.

I doubt genuine Mugen would produce a product which lost power. Maybe the Xforce copies are crap... but still don't think they'd lose power.