New straight exhaust

[Darth IQ73]

Allright IQ'ers, 

I'm thinking of getting a straight through exhaust system, one that Powerflow were doing.

Someone posted on here with one fitted a while back but I can't remember who....

My question is, would this affect any emissions or sensors or anything like that?

I'm think not, as the emissions coming from the engine into the manifold and out are not being manipulated by a baffle/silencer or back box etc.

Would a silencer only 'quieten' the exhaust noise or does it do another job?

 

I'm prepared to go ahead with it, if only for the sake of a few more mpg, but if it's going to ramp up my emissions and maybe affect Tax, so that 'shock horror' I might actually have to PAY tax, then I might reconsider...!?!

Anyone have any dealings or expertise on this?  Cheers all.

Matt

[2015iQ]

Hi Matt.  Any car that I've had with a modified exhaust system has never affected emissions/sensors. The catalytic converter takes care of emissions, and imo it's best to have a cat-back exhaust system ( i.e. the new exhaust is fitted from the cat and not the manifold). Silencers help keep the noise levels down and silencers/exhaust systems also are responsible for back pressure too. Powerflow or whoever you go to will advise.

You'd best check with your current insurers as anything that's fitted on the car and wasn't there when it left the factory is considered a 'mod'. (I don't mean the park and scooter definition ;) ) Failure to notify insurers can result in them possibly refusing to pay out in event of a claim. Also the boys in blue can check if mods are declared.

[Kuneha]

Car tax is based on its emissions (2001 onwards) and if your vehicle has excessive emissions for any reason (during an MOT), you don't have to pay more TAX, your car just fails its MOT.

Out of curiosity, and I don't mean to rain on your parade but why would you want a noisy exhaust on a 1.0 iQ?

[Darth IQ73]

Thanks all.

its purely for aesthetics, I like the look of it, the sound it a bonus, but a bit more mpg is appealing too.

i doubt it'll sound THAT different in all honesty.

[Hairy Nugget]

The biggest restrictor by far is the cat. If you want to reduce backpressure, forget about "sports exhausts".

You will need to go for a sports type cat or a test-pipe. And as far as I know, there are no cat-less/test-pipe type of manifolds available that fits the IQ, so it will be expensive as hell.

With this in place, you might gain 2hp if you're lucky. And you will probably loose some low-down torque in the process.

Unless there is something wrong with your car that throws off the AFR, any fuel savings will be next to non existant.

 

HOWEVER, there is nothing wrong with doing it for the sound and looks. I've been on the fence about this for a while myself, but I know the 1kr-fe will sound mean on a bigger bore exhaust. And the farting at idle should be fixed with it as well.

[Prodigalseer]

You can also consider a dump valve installed on your exhaust. This will keep the factory pipes, cat and resonator/silencer. You'll pass all your emissions tests. Then, Whenever you want to open the pipe, just push the button! It will open the exhaust and give you that rumble and power you're looking for! You can run the second pipe to the rear and give your IQ a dual exhaust look, or hide it underneath. 

[povanic]

I had a custom made straight through unit from longlife stainless steel exhausts, it's 25mm wider than the original and it sounds better but mpg is worse and would say it lost a few bhp due to less exhaust compression 

[Soeley]

Matt, sorry for the late reply. 

I had a Power Flow made at Demon Tweeks, you can see at the bottom of this page in my thread.

http://www.toyotaownersclub.com/forums/topic/129583-soeleys-iq/?page=3

Hope this helps. Some more info on Page 4 as well.

 

Edited April 7, 2017 by Soeley