Next we have the full cat back system exemplified by the JoeZ and the SRT systems. Both of these systems eliminate the secondary cat, and replace all the piping resonators, and mufflers and bolt up to the primary cats. These are true dual systems. They differ in details. H pipe versus X pipe, different resonators (both have two), different mufflers, and from what I have read, different quality levels. IMHO, the JoeZ wins here. The new Borla system could be of this type. This type of system is not EPA legal, because of the secondary cat delete. However, IMO, you will have no trouble passing a sniffer test. You may have a problem in California. But, if it were me, and it was. This is the system I would choose. Again, IMHO, the JoeZ is the best of the breed. A pict of the stock and the Joe system side by side, sans the rear (or axle back) section is attached.

Lou

 

The last type of system, is not yet available, but I believe Borla will have a system similar to what I am about to describe. It will be a full dual system, that attaches to the rear of the secondary cats replacing the factory resonator with two resonators (or perhaps just two straight pipes) and two mufflers. Why don't we call this a secondary cat back system? As far as horsepower gains are concerned, you will get most with the full dual cat back system, followed by the full dual secondary cat back system, and the smallest gain with the axle back system.

Lou

 

hey guys now I'm confused as well, when I spoke with the Borla rep. he described the system as a cat back that would NOT remove the primary or secondary cats. From the photos provided on his thread I would guess the borla system will be similar to the Tanabe or "axleback" which may acct for the @ 8-10 HP gain he quoted. He also shared that unlike the Tanabe, the borla will still use the stock quad exhaust defusers. To end all speculation I have put another call into my source at Borla and as soon as I have more info. will pass it along. As great as the Joe Z system is and it does sound awesome, when I went for test ride (friend had one recently installed) seemed like the slightest acceleration produced a pretty loud result inside car IMHO. As I stated before borla could be nice compromise.

 

^ Yea unless they replace the mid section then its just an axle back like everyone and there brother. 800+ for an axle back is a ripe off IMO. I am sure it will sound sick but you can do it yourself for much less just buying there muffler direct. I was quoted 250$ to do that as a custom set up on the GS. Basically the same work for the ISF. This is probably more then enough unless someone is going to boost their ISF.

 

Great write up, thank you Lou

 

Great description Lou! Haha, those pictures look AWFULLY familiar...

Javier

 

When I first installed the JoeZ I also felt it was a little loud. But I can tell you after having it on the car for 400 miles now the exhaust sound has calmed down a bit and I truly love it. I would recommend this system to all.

I have read other threads where people are trying to find a budget system for this car, and I can tell you I do not know how someone can put $200.00 hack job on a $50K-$60K car. If you look closely at the JZ exhaust it is a quality piece and these cars warrant it or a similar system, not something created by the local muffler shop. Just my $.02.

 

^+1 for the initial loudness. When I first put it on I thought I had made a big mistake b/c of how intrusively loud everything was. Almost 1700 miles later and the thing sounds amazing. It has definitely more manageable but still sounds like a beast. Built quality is sweet. Cutting corners won't get you anywhere with an exhaust. Seems like that's what lexus did from the start and we all saw how that ended up with the 2-1-2 restrictive exhaust setup.

 

^ You guy's should go out and take sounds clips of the JZ for us!

 

I'll try to do that later today or tomorrow and post em up.

 

If Borla's product for the IS-F is in anyway similar to the IS350's craftsmanship it certainly won't be on my wish list. Check out this review. https://www.clublexus.com/forums/per...d-exhaust.html

 

If you read my first post on the preceding page, you'll see that that's been my experience as well.

Lou

 

FRE have you dynod your car yet?

 

ok guys here's the straight skinny, borla will be offering (2) diff. systems for the IS-F and both will be available within the next two weeks. The first is a true dual exhaust cat back very similar to Joe-Z and will be labeled "not for street use". However we all know that's just to cover any potential legal issues. The second will be an axle back. I was told both systems have gone thru extensive flow bench testing and are completely custom engineered. The mufflers will also be unique to the F with dual stacked outlets matching up to the stock quad exhaust diffusers. Can't comment on the quality problems some have expressed with borla but the rep I spoke with was very knowledgeable and quite ethusiastic about these new products. Will be hearing from him as soon as the exhausts are officially launched and will keep everyone posted. It's just great to see another company (especially the size of borla) that thought enough of the F and our still VERY small community to invest the necessary time & engineering resources to develop these products!!

 

Pretty cool about the stacked outlets to match up to the stock quad diffusers. Looking forward to seeing how it turns out and hope they have worked out their quality control issues.