dual 2.5 is waaaay too big for the is250. Hell, it's too big for the 350. I bet you lost a good amount of low end torque.

2.25 is reasonable but still too big really.

 

How do you figure? I felt nothing but gain. It's actually really torquy now

 

Thanks I will look into that more

 

Oh yea is your system custom or pre-made what's is in it?

 

I just know that there needs to be some pressure on the exhaust side to maintain your low end torque. A true dual 2.5 system can flow enough air for a 6.0 Liter v8.

There is no way that a 2.5 liter, 6500rpm, NA engine needs NEAR that much back end flow. Like I said, 2.25 is technically more than enough for a 3.5.

 

Looks like some good welds! Be interested in your final costs.

 

It's all in your head man. You're not gonna notice 5-8rwhp.

 

What shop made the exhaust? Quality looks excellent.

 

Hey everyone this is the modified cat back exhaust system. So basically we chopped the flexes out because it actually made the system shake. Also we added an x-pipe magnaflow. It toned down the sound a lot. Not sure of the power gain like most people said but it sounds great.

 

Looks great! Nice work on the revisions, are you happier with the sound now as well?

 

yes i am its not as loud but its a better sound. as soon as i get a sound clip i will post it. I think if i want it louder i will eventually get electric cut out so i have options.

 

Nice custom exhaust setup . I love the weld job, very precise and clean. Care to share where in CA this shop is at? Anything I need welded I'll definately consider going to him first if he's local.

 

2.2" is the EXACT size for maximum benefit on an IS250. I did 2.5" as well because it was in stock and i wanted my exhaust done. Doesn't really matter, neither would give a sufficient hp increase that onee can actually feel, but 2.5" allows u to supercharge in the future without the need for exhaust modification Btw we have very similar setups, except that i have an actual X pipe. Your welds are much nicer than mine though
nice work! interested to see dyno results

 

Interesting custom projects....

Good thing we took all the guessing out of the equation over 4 years ago...

~ Joe Z

 

great job on the exhaust and you got a badass welder too, bro!!!