New Exhaust Mods

Last week I got my custom axleback exhaust.

It' s a 2.5"pipe, all in 304 stainless with an X Force MP02 Oval Hi Flow 6x10x16"muffler, also polished 304 stainless, (highest grade available) with a 2.5" inlet and a 4.5" double walled resonator tip. (4†internal Diameter)
Muffler has a 10yr warranty.

http://xforce.com.au/universal_items/list_mufflers/

My extensive research and some advice given to me by several people with many yrs exp in the exhaust business yielded the following facts which may save you all some computer time.

Firstly the 2†OD systems fitted to our cars by Mitsu is the correct internal diameter for our stock engines flywheel HP. A slightly larger 2.25†OD pipe would be slightly better, BUT 80% of the restriction in our stock systems is caused by the chambered muffler.
The accepted guide figure is for every 60HP at flywheel you require 1â€Âsquare of exhaust pipe area.
Our 2â€ÂOD pipe has an internal area of 2.7â€Âsq.
152HP/60= 2.5â€Âsq. So we have a little to spare.
Several shops mentioned going to a 2.5†catback would be too large for no appreciable gains over 2.25â€Â.

I didn’t think a full 2.25†catback system with a new resonator removing the 2 factory resonators was worth an extra $400-500 to gain a small extra increase in performance over what I got with my axleback.
That is up to you to decide for yourselves.

Secondly, the factory system is all 409 stainless (as it is on all new cars) so be wary of shops wanting to keep your costs down for a full catback by replacing stainless with mild steel.
To me that idea is just ridiculous.
Same with shops recommending ACMS hi flow mufflers which have a 2yr warranty, 409 stainless has 5 yrs.
I had a Mitsu Eclipse Turbo for 13yrs and the stainless exhaust ,which was all stock was as good as new the day I sold it after all that time and 100,000km.

The new muffler was mounted in same position as the stock one, from the stock flange point with a 90* and then 180* mandrel bend to the inlet and then a 90* bend to the tip.

This has a nice deeper than stock note but is virtually as quiet as stock at all times except when accelerating when it is slightly louder than stock (from inside car with windows closed). It is MUCH QUIETER than a cannon when accelerating either part throttle or full throttle.
I imagine most of the imported cannons from the US and Japan would be the same, ie much louder.

This mod along with a K & N drop in filter has greatly improved the driveability of the car esp at the lower RPMs under 3500 RPM. I also cut out a larger opening in front of the air intake scoop as on the Ralliart and Evo in place of the very small grill on the NA models.


It now breathes a lot better and as a result the throttle response and engine acceleration is noticeably quicker than stock which is a result of more low down torque. ( Remember it is Torque, NOT power that gives acceleration low in the rev range).
As with all mods of this type the extra wheel HP is gained at the high end of rev range above 4000 with the peak gain between 5-6000 RPM.
With the MIVEC our cars already have pretty good acceleration above the 3500RPM point for a NA engine. (God I miss my Mitsu Eclipse Turbo)

I can highly recommend these mods for a performance increase at relatively low cost.
Anyone here in Perth can PM me if you want the details of the shop where I got it done.
I will try and post some pics when I get a chance.

 

Here are some pics of my car, a stock rear view then after the new mods.

[URL=http://img385.imageshack.us/my...ageshack.us/img385/983/lancervrxpu4.jpg[/img][/url]

[URL=http://img122.imageshack.us/my...ack.us/img122/9738/stockrearviewfq1.jpg[/img][/url]

[URL=http://img389.imageshack.us/my...ck.us/img389/2807/lancerrearviewxp0.jpg[/img][/url]

[URL=http://img389.imageshack.us/my...shack.us/img389/7307/lancervrx7ctj0.jpg[/img][/url]

[URL=http://img117.imageshack.us/my...shack.us/img117/3664/lancervrx7dyv7.jpg[/img][/url]

[URL=http://img117.imageshack.us/my...eshack.us/img117/738/lancervrx7ect3.jpg[/img][/url]

Here is a pic of the cut out for the air intake. This is essential in my view as the little slots in the standard plastic trim piece are equal to an intake area of about 2 square inches only!!!!
I have no idea why the Mitsu engineers would literally set it up to completely choke off the engines air supply.
For those who haven't noticed, the hood leading edge seals against the hood weather strip behind the bumpber panel and inside is sealed against the top of the air scoop intake by a rubber strip that runs along the entire edge of the black trim piece so the only way the air can effectively get into the scoop is through the original slots.
I did not cut any further towards the centre of the car as there is a vertical reinforcing tab molded as part of the trim piece on the underside.
If you look at the pic below of the EVO/RA engines you can see the large holes provided by Mitsu in front of the air intake scoop, the centre divider is covering the metal bumper bracket.

[img]http://img384.imageshack.us/img384/2388/ralliartengineur9.jpg[/img]

[img]http://img122.imageshack.us/img122/3301/intakecutout1rg7.jpg[/img]

[img]http://img385.imageshack.us/img385/5652/intakecutout2zv3.jpg[/img]

 

Hey Nick,
Will do when I get a chance. i'll add it to the above pics in that post.

 

Hi Guys,
Thanks for the compliments.
I have added the new intake pictures to my above post .

There was no way the muffler would not show under bumper due to its size , (6x10"oval shape) and the 1" clearance to the heat shield.
I got that size so it would not be too loud. Our noise limits here in Aust are lower than the US as far as I know, 88-90 Db in all states.

As I stated in my opening post the 2009 models have an oval muffler replacing the squarish can we got in 2008. It is smaller than 6x10" ,probably a 5x9" and so doesn't stick down so much, an inch makes a difference,it is longer than mine though.

 

Exhaust is as quiet as stock at idle and when cruising with the windows shut. When accelerating either part throttle or full it has a slightly louder than stock sound level that is more throaty growl compared to stock.
A friend had a no name aftermarket cannon and it was VERY loud when accelerating compared to mine.
I didn't want that as it was just too loud. I am very happy with the sound and performance increase.

 

Thanks for all your comments guys.
The intake mod I did is an ABSOLUTE MUST if you are are keeping the standard airbox as I did and installing a K & N or Works Filter as otherwise the engine is basically completely choked by having an effective intake area of approx 2sq inches to feed outside cold air to the intake scoop tube.
I have no idea what the Mitsu engineers were thinking but would love to ask them :roll:

 

Hey mpirklbauer
I already thought about that too.
Looks like it from the pics.
Although it is a wider scoop opening on the RA ( not choked off by plastic molding) if it narrows to the same size tube where it enters and forms the inlet side of the airbox as on the NA it probably wouldn't be worth the cost of trying to swap it over as OEM parts are usually overpriced and I doubt there would be any noticeable performance increase anyway..