Probably more so on the 350 than the 250

Lex

 

is this the IS250 or the IS350?

 

Touche!

(I actually like the IS350's note, muted as it is - I think with a little work it will be really nice)

 

Anyone notice that on at least the IS350 that the exhaust shakes? I was driving a IS350 and I noticed that the exhausts shakes as if its not bolted on tight enough.

 

How the hell you look at your exhaust while your driving?

 

Look at that Transmission drain plug. That's good to see.

Timbois, do you know where the oil filter is?

I wonder if it is a cartridge or spin on? You all know?

We need to start a motor thread. Its listed aluminum motor, It must have iron or
some magnesium sleeves for the cylinders for longevity. You all know?

 

Bingo! My friend told me about this when he was behind me. I wonder if there is some sort of problem with it?

 

Haha ... you got me. I meant to say "I was driving behind a IS350 and noticed it". Thanks

 

Can anybody reference their manual and find out if those two bulges right in the middle of the exhaust are resonators or are they catalytic convertors? If they're cats, that's a whole lot of extra restriction along with where the exhaust pipes mingle after them...

I think there is some good HP to be freed up in this exhaust while still keeping emissions clean: Aftermarket equal length headers, high flow cats for the first set of cats, eliminate the 2nd set of cats at the middle (if they really ARE cats), have an "H" pipe to synch up the exhaust pulses before the current 2nd cat location, then keep the exhaust true dual all the way out without merging the pipes. It would definitely sound more aggressive but shouldn't be obnoxiously loud, and all of the above ought to be good for 10-20 WHP...maybe more...who knows?

 

Looks like resonators, usually the cat is before the resonator and you can sort of make out the cat closer towards the headers.

 

Yea, I think they are resonators the more I compare them to the end of the cats that are visible up top.

I'd love to see the kind of exhaust I posted above, but my plan for when I buy an IS next year is to leave it pretty much stock and mod another car that won't be a daily driver. Now I just have to make myself stick to my plan.

 

some more undercar pics



oil filter in there?

 

take a look at some magazine exhaust before and after comparison on non-FI'ed cars. You'd be hard pressed to gain any more than 5 horsepower from just an exhaust.

before the "butt dyno" gains happen, do a baseline dyno with the car, and a post-exhaust dyno.

 

Thanks for those pics, wolverine.

It looks like that first "Y" section is the most restrictive part of the exhaust. It also looks like there's enough room to go true dual all the way back, though. Just cut after the dual resonators, add some custom bent tubes back to a pair of high flow mufflers, then put an "H" pipe before the resonators and the exhaust side is set until the aftermarket comes out with high flow cats and equal length headers.

 

getting rid of as much backpressure as you can isn't the proper way to tune or "optimize" an exhaust syst***s performance on an NA car. There is an optimal level of exhaust velocity that is needed to make decent power, and to figure out exactly where this point is is quite difficult. i'd be interested in seeing some before and after dyno charts when this hks exhaust does finally come out.

and it'll be important to look not just at peak hp gain, but overall gain or loss underneath the power curve in its entirety.