Is the diameter of hte TRD axle back any larger than the stock section?

 

There is a small HP gain and TRD EXhausts traditionally run at 85 decibels so they're street legal. It's always a good full round sound, nothing obnoxious. They are also being closed out by TRD and have big discounts on them.

Ken

 

According to a reputable tuner shop you should gain 5-10hp with the TRD axle back exhaust ONLY if you replace the last piece of 1.5 inch pipe that mates up with the TRD exhaust and muffler. Estimated cost for the replacement here was 2-3 hundred dollars to replace that piece.
I noticed no gain with just the TRD axle back exhaust but noticed a sizeable gain after putting the Fujita CAI on my car. It also sounds louder once you hit about 4000rpm. Don't waste your money at the dealership getting a "TRD intake", it's basically just a K&N type filter in the airbox.

 

10hp seems to be a bit on the VERY optomistic side of things as an exhaust for this car on its own (1.5in piece replaced or not.) I'd say easily exhaust combined w/intake no problem. (5-7hp intake + 3-6hp exhaust = 10+hp). I've just never personally seen anyone estimate hp gains like that from ANY exhaust setup alone. maybe i'm wrong.

I havent got a quote myself yet but $300 seems high for one piece of pipe, but if you meant full install + pipe replacement, then perhaps $2-300+.

Just pointing out that this would contradict your earlier statement, and confirm my suspicion that the axle back does less than your shop would think. I'm pretty sure most people could feel an extra 5-10hp if it were there? But maybe i'm wrong again.

 

The point the shop made to me is that I'm not seeing any gains in the much more free flowing axleback TRD because of the pipe leading into it. I believe them when they say that finishing off the restrictive few feet of exhaust would net me 5-10hp in gains.
That would essientally give you a 2 1/4 inch exhaust all the way to the header. Yes, that will gain you that much HP. I've seen sport mufflers alone on bigger engine cars give up to a 20hp gain on a dyna without any exhaust mods.
As far as the price, to do it right....time on a mandrel bender is very expensive. That's cheap for what you're getting along with welding time, parts and fittings.
I agree it's alot for little gain. But it all adds up.
Lightweight Flywheel and clutch are next for me if anyone has any ideas or has done this already.

 

i hear ya. Wish there were some dyno charts out there for exhaust. I've seen a bunch for intakes, but havent run across any dyno charts for exhausts.

Flywheel sounds like agood next step.

What are you planning to do with your clutch? I dont know whats out there clutch-wise.

 

i had the TRD axle back, and there are NO noticble gains with it by its lonesome. there is also a lot more restrictive piping than just the last 1.5" of piping before the axle back. take a look under the car, its crappy the entire way after the second cat.

however, after i replaced the ENTIRE catback, i noticed a tiny bit of upper end. i paid $120 bucks for 2.25" catback to be bent and fit. you do not need mandrel bent piping on this car unless you are going to be going A LOT further with the NA mods (which arent available yet, if ever), remember you still have two restictive cats and a stock exhaust mani before you even get to the catback.

 

Was $120 for the cat to the axle or the cat all the way back. That is a pretty good price.

 

did you get rid of it and opt for something different?

 

i meant to say i had just the axle back, but now i have the full catback + axleback, 2.25" the whole way.

it was only $120 from the cat to the axleback because it wasnt mandrel bent, which is currently unnecessary for any NA setup on this car. if the exhaust shop is good, they will make the crush bends gently and they will be quite close to mandrel.

 

did the 2.25" piping louden things up any more than just axle back alone? did you remove the secondary cat?

 

it is definitely louder than just the axleback. i did not remove the second cat, but removed the resonator right after it, which also contributes to higher noise now.