Russelbhag

I have a scion tc 2008 and i bought a cat back for it and a new manifold both don't have a catalytic converter but the stock ones have two.

so i recently put on the cat back and took off the 2d catalytic converter so i only have 1 in the stock manifold and my gas is going away fast i have to fill up every 3-4 days

now the new manifold does not have a catalytic converter should i put it on and put back in the stock mid pip with the catalytic converter or soul i just put in the new manifold and leave it with out a catalytic converter


i live in Florida so we have no laws for catalytic converter

i just wanna know how other people save gas with new exhaust and manifold if they donut come with catalytic converter

Basebllstar

I'm finding it difficult to read what you've written so I'm going to try to clarify. Originally you installed a catback exhaust without a Cat and you had only the single Cat in the stock header. Now you have a new Cat-less header and are curious about whether you should reinstall the original Catted exhaust?

You should see better results in MPG without the Cats. It is possible that the Cat in your header is clogged and reducing your MPGs. After installing my Dezod catted header, I noticed better MPGs; I assume my header was getting old and mucked up.

I say install the Cat-less system and see what happens. You've already spent the money; might as well install it.

Also, how far are you driving every 3-4 days? If its around 300 miles, thats not far off from normal MPGs.

Russelbhag

No I recently bought a cat back exhaust it has 3 pipes leading from the 2d o2 sencer.

I put on the cat back exhaust and kept on my stock manifoild and my gas is depleting really fast I have to fill up every 3-4 days

Now the stock scion has 2 catalytic converter one past the 2d o2 sencer and one on the manifoild

When I changed the stock exhaust to the cat back it didn't have a 2d catalytic converter(so I think) so I only have one catalytic converter in the manifoild

Basebllstar

Installing a catback won't affect MPGs negatively. The Car can't even see the 2nd Cat because the sensors are right before and after the Cat in the Header.

How far are you driving in the 3-4 Days?

Do you have a CEL?

Russelbhag

Not far like 1.9 miles

What is CEL ?

Basebllstar

Uh. so you're using up ~12 Gallons of fuel for 1.9 miles?

Check Engine Light.

At this point, I'm not sure I'll be able to help you. If it really is a problem, I suggest taking it to a mechanic because this "over the internet" diagnostic thing isn't working.

06ScionTc5sp1

My only guess to your situation is that, something else is effecting your fuel mileage. A new Cat would help but, it most likely a simple part. Like an dirty air-filter, an clog fuel injectors, a bad spark plug or most cases, your fuel filter itself. Of course, if you are living in a city and have to deal with rush hour traffic everyday and your driving an stick-shift...that will suck your mileage even more. Plus, your tire pressure will effect your fuel too (if it's below normal 32 psi)

Even like my 5 speed Tc, last week. My car last 5 days before fueling up again on 87 grade while driving 23 miles a day for work. So, this week I'm using 89 grade. Not sure if it will make a difference though. However, 3-4 days every fill up seems to be normal these days for everybody. Except for those who drives motorcycles, that can last 7-9 days. So, don't feel bad. Most of us are probably fueling up every 3-4 days too.