Experimental Exhaust System

[Tofuboi]

Just a word to all the Aurion people out there.

Alot of people have tried different exhaust systems on the Aurion which has caused various differences such as loss of power, droning under load etc.

Just letting you all know basically myself in conjunction with A1 Exhausts will be using my car as an experimental vehicle to attempt to deisgn and create an optimal exhaust system that will hopefully eliminate the droning and loss of power issues. Will keep you guys posted on further updates. :)

[DJKOR]

That is very nice of you ;)

Certainly will be good for those of us wanting to push for performance. I think I will stick with my ideas of getting a Varex though. Mainly because I want something that can be quiet for the neighbourhood, but I also want it loud for the hoon in me. I just don't think I could handle a single solution. That's just me though. I am curious about your results however.

[ELEGNT]

thats great news!!

ive got supercat mufflers on mine and it doesnt drone (if anything i really i want it to be louder) but there is no noticable power increase which is a bit of a let down.

im interested to see what they decide on doing with the squashed pipe section, do you have any idea? i think this will be the key in gettin more power out of the car.

when are u starting ur experimenting? and wil you be dynoing it or just go by feel?

Edited January 7, 2009 by eSEXSIX

[apg39]

I too am doing some 'exhausting' investigations.

Brother has a welder on his work truck so one weekend soon were going to get under the car & do some proper work, at the moment he thinks we may be able to remove the last 1-2" of both sides of squashed pipe & put in a new piece of kinda sideways Y pipe. I keep meaning to do a write up + illustration but I've only got the net at work for the moment. Its all done at home on my laptop.

I've done some price chasing on a Borla diff-back (from US v6 camry) and I can buy it for $800 + freight (both sides). A local (Perth) distributor has quoted me $1700 (!!!!!!) for the lot. Hence why I'm looking around more.

Aside from that I'm looking for straight through mufflers with either twin 2" outlets or single outlet & a twin 2" tip. Managed to find a few but Ill wait to see what the Borla is worth versus making my own. Also the Varex is in the back of my mind.

Also looking at fabricating a proper 2" or 2 1/4" pipes coming from the diffback (where it splits 1 into 2) if I do my own muffler job. May as well get a quote to do a full system from the headers back with hi-flows while Im at it.

I doubt HiTech are still going through with their TRD exhaust now that TRD has been dropped, but I'll try find out.

I shall keen you posted but Im moving house this month so dont expect any action yet.

Edited January 8, 2009 by apg39

[apg39]

remove the last 1-2" of both sides of squashed pipe & put in a new piece of kinda sideways Y pipe.

Dodgey Paint illustration.... worst part is that sensor right nearby so we can cut too much of the rear header pipe

Similar to the join on this one....but not so much a right angle, preferably smaller angle so the exhaust is still flowing in the same direction.

Edited January 8, 2009 by apg39

[ELEGNT]

wouldnt the 90 degree angle make too much turbulance?

wat about these

XXXd.bmp

XXX.bmp

[apg39]

wouldnt the 90 degree angle make too much turbulance?

....but not so much a right angle, preferably smaller angle so the exhaust is still flowing in the same direction.

- but Ill be able to see what kind of angle is possible once I can get under the car instead of taking pictures as reference.

Your pictures are the right idea, but cos the 2 pipes are already squashed, you'd need a new straight section from the front header to the cat, then cut a scallop in the side for the rear header to be welded into.

Another dodgey Paint illustration.... (angles aren't correct)

[ELEGNT]

wouldnt the 90 degree angle make too much turbulance?

....but not so much a right angle, preferably smaller angle so the exhaust is still flowing in the same direction.

- but Ill be able to see what kind of angle is possible once I can get under the car instead of taking pictures as reference.

yeh sorry i missed that skim reading at work lol

yeh this will be where most of the restriction in the exhaust will be by far...and it should perform alot better high in the revs once freed up. yet it is a very tricky bit to get right so good luck!

keep us posted :D

[e240]

The only way to maintain the same power throughout the rev range is to have exactly the same restriction throughout as stock. How are you testing the benefits? Going to test on a Dyno?

From what I've seen, the greatest restriction occurs where the headers from the 2 cylinder banks merge. There, the pipes literally becomes flat. Someone needs to design better headers.

I'll also say as you make the exhaust less restrictive, to fully maximise the gains/improvements, you will probably need to add on a piggy back, otherwise, IMO, its really not worth it.

[Tofuboi]

Yeah it's going to be an interesting experiment that's for sure. I was pondering doing the testing by feel but I am leaning more toward a dyno test at the moment.

We had the car up on the hoist and basically he pointed out the two most restrictive areas on that exhaust are the huge resonator behind the final cat and the flat part you described.

We were going to try design some custom headers but we're unsure as there aint much space... The sensors become a worry too. We will definately just setup a mostly straight through system with a hi-flow at the final cat. But what good is a hi-flow if the other two cats on the headers are restrictive...

Either way it's going to be fun.

[e240]

Good luck and will be watching this thread.

If you were in Sydney, I could put you through to my tuner who can install and tune the piggy back to maximise gain.

unfortunately, that would void the warranty on many of our cars..*Sigh* only 5 years to go before I can turbo charge the car..LOL..

Yeah it's going to be an interesting experiment that's for sure. I was pondering doing the testing by feel but I am leaning more toward a dyno test at the moment.

We had the car up on the hoist and basically he pointed out the two most restrictive areas on that exhaust are the huge resonator behind the final cat and the flat part you described.

We were going to try design some custom headers but we're unsure as there aint much space... The sensors become a worry too. We will definately just setup a mostly straight through system with a hi-flow at the final cat. But what good is a hi-flow if the other two cats on the headers are restrictive...

Either way it's going to be fun.

[ELEGNT]

Sigh* only 5 years to go before I can turbo charge the car..LOL..

5 years? extended warrany??

[e240]

Sigh* only 5 years to go before I can turbo charge the car..LOL..

5 years? extended warrany??

yeah, not sure if its worth the trouble now.. :-p

When I first got the car, it was meant to be a straight family car - no mods, nothing...nothing at all!

Edited January 8, 2009 by e240

[apg39]

Sigh* only 5 years to go before I can turbo charge the car..LOL..

5 years? extended warrany??

yeah, not sure if its worth the trouble now.. :-p

When I first got the car, it was meant to be a straight family car - no mods, nothing...nothing at all!

Yeah....mine wasn't meant to be modded either.

Oops.

:D

[DJKOR]

When I first got the car, it was meant to be a straight family car - no mods, nothing...nothing at all!

LOL. I recall SecaBoy saying the same thing. I said the same thing as well, but it is so easy to get carried away; especially when others start doing things as well.

[the_random_hero]

Varex's and the like are completely and utterly pointless, IMO. It's not hard to make a system that's sufficiently loud when it has to be, but won't drone or impose too much restriction.

Bolt ons to NA engines don't make power by themselves, they open up the opportunity of better tuning the engine at the cost of losing low down torque - that's a fact that has been proven many, many times. Get a decent set of tuned length headers made up (suited to where you want your power band to occur), use a metal cat, one resonator and two mufflers (for a twin system) with an adequately sized piping for the mods you have. Mandrel bends are really only useful on the headers, on the rest of the system they are pointless.

It's a lot cheaper than a LOT of stuff I've heard people recommending.

[apg39]

It's a lot cheaper than a LOT of stuff I've heard people recommending.

Agreed, however my little home job on the squashed pipe is relatively cheap & may/may not be significant. If not then I'm proud to say I sacrificed a header to help everyone else out.

I've posted on ToyotaNation too and no ones fixed it so hopefully we can get more ideas flowing.

[Blind Kid Seeks]

Varex's and the like are completely and utterly pointless, IMO. It's not hard to make a system that's sufficiently loud when it has to be, but won't drone or impose too much restriction.

Bolt ons to NA engines don't make power by themselves, they open up the opportunity of better tuning the engine at the cost of losing low down torque - that's a fact that has been proven many, many times. Get a decent set of tuned length headers made up (suited to where you want your power band to occur), use a metal cat, one resonator and two mufflers (for a twin system) with an adequately sized piping for the mods you have. Mandrel bends are really only useful on the headers, on the rest of the system they are pointless.

It's a lot cheaper than a LOT of stuff I've heard people recommending.

mate, your full of it!!!

i have increased peak KW by 20 At the wheels from Bolt ons. and this HAS been proven time and time again.

get the RIGHT bolt ons, and you WILL make more power.

VAREX mufflers are excellent, and i am so glad i have one. It doesnt drone, and is sufficiently loud or quiet whenever i want it to be.

as far as mandrl bends being pointles... why would they make the system from mandrel bends stock then?

[Pumped]

I doubt HiTech are still going through with their TRD exhaust now that TRD has been dropped, but I'll try find out.

Any further information on this?

did they ever make one or was there just talk of it?

cheers

[the_random_hero]

Varex's and the like are completely and utterly pointless, IMO. It's not hard to make a system that's sufficiently loud when it has to be, but won't drone or impose too much restriction.

Bolt ons to NA engines don't make power by themselves, they open up the opportunity of better tuning the engine at the cost of losing low down torque - that's a fact that has been proven many, many times. Get a decent set of tuned length headers made up (suited to where you want your power band to occur), use a metal cat, one resonator and two mufflers (for a twin system) with an adequately sized piping for the mods you have. Mandrel bends are really only useful on the headers, on the rest of the system they are pointless.

It's a lot cheaper than a LOT of stuff I've heard people recommending.

mate, your full of it!!!

i have increased peak KW by 20 At the wheels from Bolt ons. and this HAS been proven time and time again.

get the RIGHT bolt ons, and you WILL make more power.

VAREX mufflers are excellent, and i am so glad i have one. It doesnt drone, and is sufficiently loud or quiet whenever i want it to be.

as far as mandrl bends being pointles... why would they make the system from mandrel bends stock then?

Bolt ons only remove factory power losses, they don't make power. Stock systems are generally smaller than the ideal system, hence the use of mandrel bends. You'll also find that in a mass-production facility, they are generally as easy to do as press-bends.

[Blind Kid Seeks]

Varex's and the like are completely and utterly pointless, IMO. It's not hard to make a system that's sufficiently loud when it has to be, but won't drone or impose too much restriction.

Bolt ons to NA engines don't make power by themselves, they open up the opportunity of better tuning the engine at the cost of losing low down torque - that's a fact that has been proven many, many times. Get a decent set of tuned length headers made up (suited to where you want your power band to occur), use a metal cat, one resonator and two mufflers (for a twin system) with an adequately sized piping for the mods you have. Mandrel bends are really only useful on the headers, on the rest of the system they are pointless.

It's a lot cheaper than a LOT of stuff I've heard people recommending.

mate, your full of it!!!

i have increased peak KW by 20 At the wheels from Bolt ons. and this HAS been proven time and time again.

get the RIGHT bolt ons, and you WILL make more power.

VAREX mufflers are excellent, and i am so glad i have one. It doesnt drone, and is sufficiently loud or quiet whenever i want it to be.

as far as mandrl bends being pointles... why would they make the system from mandrel bends stock then?

Bolt ons only remove factory power losses, they don't make power. Stock systems are generally smaller than the ideal system, hence the use of mandrel bends. You'll also find that in a mass-production facility, they are generally as easy to do as press-bends.

you make me laugh,

remove factory losses?? c'mon man. you think car manufacturers, design exhaust systems to make less power???

seriously! economy is one thing but when you're after sales... well thats when facts and figures stack up.

if you can get mandrel bends for the same price as press bent straight pipe, let me know,... i want in!

[DJKOR]

if you can get mandrel bends for the same price as press bent straight pipe, let me know,... i want in!

He didn't say it is the same price. He said, and quote:

You'll also find that in a mass-production facility, they are

generally as easy to do

as press-bends.

Which is understandable. With the fact that they would have the equipment for the job which is used on such a large scale that it is essentially no big cost for them, they can perform the required work at the factory without the need putting a mark-up on the mandrel bending. When you get mandrel bending done, it's not like the person operating the machine needs to exert a lot of effort. The machine does all the work. Operators of a mandrel bender can charge extra for the process simply because they can. In the factory scenario, it would barely make an impact.

[the_random_hero]

Varex's and the like are completely and utterly pointless, IMO. It's not hard to make a system that's sufficiently loud when it has to be, but won't drone or impose too much restriction.

Bolt ons to NA engines don't make power by themselves, they open up the opportunity of better tuning the engine at the cost of losing low down torque - that's a fact that has been proven many, many times. Get a decent set of tuned length headers made up (suited to where you want your power band to occur), use a metal cat, one resonator and two mufflers (for a twin system) with an adequately sized piping for the mods you have. Mandrel bends are really only useful on the headers, on the rest of the system they are pointless.

It's a lot cheaper than a LOT of stuff I've heard people recommending.

mate, your full of it!!!

i have increased peak KW by 20 At the wheels from Bolt ons. and this HAS been proven time and time again.

get the RIGHT bolt ons, and you WILL make more power.

VAREX mufflers are excellent, and i am so glad i have one. It doesnt drone, and is sufficiently loud or quiet whenever i want it to be.

as far as mandrl bends being pointles... why would they make the system from mandrel bends stock then?

Bolt ons only remove factory power losses, they don't make power. Stock systems are generally smaller than the ideal system, hence the use of mandrel bends. You'll also find that in a mass-production facility, they are generally as easy to do as press-bends.

you make me laugh,

remove factory losses?? c'mon man. you think car manufacturers, design exhaust systems to make less power???

seriously! economy is one thing but when you're after sales... well thats when facts and figures stack up.

if you can get mandrel bends for the same price as press bent straight pipe, let me know,... i want in!

Yes - not intentionally, but to save a couple of bucks they will. It's a well known fact, hence the reason people buy aftermarket extractors. Check out 1UZ-FE exhaust manifolds, then come back to this thread :)

Edited January 9, 2009 by the_random_hero

[hillbilly1uz]

Varex's and the like are completely and utterly pointless, IMO. It's not hard to make a system that's sufficiently loud when it has to be, but won't drone or impose too much restriction.

Bolt ons to NA engines don't make power by themselves, they open up the opportunity of better tuning the engine at the cost of losing low down torque - that's a fact that has been proven many, many times. Get a decent set of tuned length headers made up (suited to where you want your power band to occur), use a metal cat, one resonator and two mufflers (for a twin system) with an adequately sized piping for the mods you have. Mandrel bends are really only useful on the headers, on the rest of the system they are pointless.

It's a lot cheaper than a LOT of stuff I've heard people recommending.

mate, your full of it!!!

i have increased peak KW by 20 At the wheels from Bolt ons. and this HAS been proven time and time again.

get the RIGHT bolt ons, and you WILL make more power.

VAREX mufflers are excellent, and i am so glad i have one. It doesnt drone, and is sufficiently loud or quiet whenever i want it to be.

as far as mandrl bends being pointles... why would they make the system from mandrel bends stock then?

Bolt ons only remove factory power losses, they don't make power. Stock systems are generally smaller than the ideal system, hence the use of mandrel bends. You'll also find that in a mass-production facility, they are generally as easy to do as press-bends.

you make me laugh,

remove factory losses?? c'mon man. you think car manufacturers, design exhaust systems to make less power???

seriously! economy is one thing but when you're after sales... well thats when facts and figures stack up.

if you can get mandrel bends for the same price as press bent straight pipe, let me know,... i want in!

Yes - not intentionally, but to save a couple of bucks they will. It's a well known fact, hence the reason people buy aftermarket extractors. Check out 1UZ-FE exhaust manifolds, then come back to this thread :)

Actually 1UZ manifolds are made that way so they can fit in the respective engine bays they are going in, not to save on cost. But I see your point......

[Tofuboi]

Well so far not so good unfortunately...

After a complately new system was fabricated (manifolds included, with sensor stuff so it wouldnt cause issues)... Well it did, kicking up the engine managment light and restricting engine revs. While it sounded GREAT on idle, it would keep kicking up diagnostic errors, even after spending over half the day trying to adjust it.

So we reverted back to the stock setup and started working in stages, just working from the back to the front...

After fabricating new back sections (after the stock pipe splits into 2) it sounds really meaty and grumbly, although it began to drone even at that moment. 2,000-2,300rpm would just send a massive vibration through the car, drone like hell and even induce the dash rattle. Which i NEVER had until then :S

So day 1 isnt looking so hot at the moment, but theres always day 2 :) keep ya posted, and i forgot my camera so ill get some pics hopefully.