why would toyota taper the exhaust down so much towards the end? cheap way to surpress the engine noise?

 

Ain't room for a 24 behind the cat. The stock resonator (and my 20" glasspack) fit up into a central recess that runs aft from the engine bay to the end of the resonator. From there the exhaust is simply tucked up to the belly pan as it sweeps to the right side of the car and mates with the axle back assembly. There's a removable crossmember that bolts into the belly pan at about the midpoint of the resonator. The crossmember is lower than any point along the exhaust line. (I've touched it down a couple times on very humped driveway entrances.) The only way to use a longer resonator than stock is to forgo the crossmember AND let its aft end droop downwards. (Kinda hard to explain, but I'm trying!) I personally wouldn't accept either of those things for both structural and clearance reasons.

Good point about backpressure but I haven't experienced any problems. A turbo or canister at the rear would be a reasonable choice - there's room enough - and the TRD is basically a fancy-* turbo. The biggest problem I've experienced is interior noise above about 3k. It would take a lot of trial and error (money that is) to solve that one to my satisfaction, but I suspect many younger motorheads will be less concerned.

 

OK. So I got a photobucket account and can post some pics of the project. Eventually the OEM resonator was replaced with another glasspack (no pix of that). In some shots you can see the rear NF210/TRD Bar install. OEM pix first then the project pix.

The pipe is 2 1/4" but with bending is effectively 2". Glasspacks are 2 1/4 also.
As you can see there is some room for alternative rear cans.
Note the hot O2 sensor in 2nd pic. Tween the cat cans; a blessing for modding.
Also note the removable center crossmember. Because of it:
OEM resonator dimensions more-or-less define size of a potential replacement.

No apparent problems with sensor, backpressure, or clearance. 2-3% increase in highway mileage. Perhaps similar increase in top end HP. See previous post r.e. noise.

















Will try to answer questions (if any).

 

i still cant believe how small that stock exhaust is...

 

Thanks for the pictures! Bout as good as you can get without putting it up on the lift yourself.

I really am liking how the exhaust is lined up... makes for a good flow without too much effort. If I ever decide to modify the exhaust it'll be super easy.

 

Appreciate the feedback. Yep, very restricted stock exhaust but easy to modufy.

 

looks great but why didnt you take out the second cat

 

I would imagine....

For 1 it would be super noisy

2nd, why hurt the enviroment for just a couple of extra Hp.

Guess my mindset on things has been changing latley.

 

Garage pretty much answers the question. I also didn't want to end up putting in a zero sensor, fighting the electronics, and/or end up in a tiff with the state emissions folks. (Washington uses the Calif rules.)

btw Thanks Garage for the various "homeworks" you've done for us all... Will be interesting to see what you do to your rig.

 

actually my roomate took out one cat on his xrs and its not loud at all compared to most setups. but it all depends on what ur goin for all in all looks good tho

 

taking off the second cat on this car wouldn't require any altering of the electronics, as the last O2 sensor is before it... but removing it would require your own welding equipment and skills, as its not flanged in. and obviously, no exhaust shop is going to do such work for you.

 

You're probably right about the electronics but I've been surprised before. A zero sensor would probably be necessary. Sometimes it doesn't get along with emissions coding but usually it's all you need. Though I have the equipment to do the job, I actually don't want to contribute additional pollution anyway. And I certainly don't want to fail a visual inspection or void the warranty.

btw What is your custom intake? Whatdoyouthink?

 

Really once the back half of the piping is opened up that's more than enough... dropping off that second cat isn't going to do much for you.

There's an exhaust shop here in Portland that'll do any welding work you want, the guys are pretty damn cool actually

 

runaway, could you PM me the name of that shop?

seattleguy, my custom intake is simply a removal of the stock airbox, and putting a standard autozone style cone filter in its place. the filter fits perfect over the MAF sensor housing. cost like 25 bucks to do. im looking to make it a cold air with the custom pipe pieces you can buy there as well. dont know how much of a difference it actually made, but it sounds nicer.

someone would have to do additional dyno research to see if removing that second cat would even be worthwhile, you might loose a little too much backpressure and make the low end even weaker than it already is. dont know for sure though. and like you said, you probably wont be passing emissions, those guys are slowly getting smarter.

 

Oh I see (r.e. intake). For some reason was thinking of intake manifolds... (Wonder if that Mustang performance shop with the dyno chart is gonna produce their system?)

I too doubt if removing the second cat would make any positive difference to this motor (in otherwise stock form) and possibly hurt it. I never even considered doing so and the notion is amusing at a personal level.

The purpose of the "budget exhaust experiment" was to see if a cheap exhaust system could improve cruising mileage while beefing up the exhaust note as per usual. Which it does. I assume it also makes a bit more power on top, but, frankly, who can really feel a mere handful of top end ponies in these kind of cars? Otherwise, I believe that e-systems in cars used as daily drivers should be even cleaner than they are!

 

btw Thanks guys for all your responses. Wish their was a bit more talk of a technical, rather than cosmetic, nature on this site.

 

usually the stock amount of backpressure is too much, as the design is to reduce noise and such. but removing the second cat and having a full catback could be approaching too little backpressure, but again, that wont be confirmed wihtout a dyno.

i did email that mustang shop directly yesterday about that intake manifold, so hopefully i will hear something back within the next few days. dynatek has not logged onto this forum in like a month from the last time i checked. i at least want some photos to show the manifold really exists. 25hp would definitely be something youd feel!

and hopefully NST gets that pulley kit going too.

anyways, my own conclusion is that a full catback exhaust is probably the best system to run as far as power gains and practicality go. the stock header looks pretty nice, and an aftermarket will only barely be able to improve on it... so until a dyno proves me wrong, my 2.25" exhaust is done.

 

Yeah, you could feel 25 hp. As I recall Dynatek said they ran a full off road exhaust for that dyno. Wonder what the power would be with a streetable exhaust?

Let me know if you hear from them. The last post I saw from Dynatek was on another site in March. Said there wasn't enough interest in xD's and they were working on an xB.
http://www.scikotics.com/forums/show...1&postcount=65

 

i cant remember if that post you linked is before or after their last post here. im at work, so ill have to search that up later. maybe i can get them to sell me or someone the prototype, and we can take it to someone who would want to pursue the project, haha.

 

no, they didnt bother replying to anything after the 26th of feb and the other post is the 30th of march. no intake mani i guess cause most ppl just care about their rims and drop hopefully we'll get a SC from toyota at least eventually...

and i think various xD forums spreads the community too far apart too for a company to find full interest in our cars (what is there like 5 different ones?)