http://cgi.ebay.com/ebaymotors/Lexus...item2eaba748a0


I am not sure of the pipe thickness of the oem midpipe but is the above item larger?

What do you guys think?

 

Those pipes are larger than stock but I had one of the the resonators from that company and it had internal restriction. The larger capacity is only an issue if you have exceeded the stock pipes capacity which is not very likely. When I removed the Y pipe from my system for testing it lost low speed power and did not seem to have gained any top end power.

The above parts may be useful on a turbo or supercharged engine but the resonators may need to be replace by straight pipe or better resonators. This statement is NOT based on examining the parts listed and those may be ok but the resonator I received necked down inside and had sharp edges presented to the flow path. The rest of the construction was just fine.

 

^Thanks J. I too felt at first that larger exhaust piping should be left to higher output (FI) engines; but I just thought that perhaps I could get a little gain from this...I guess not. I figured I'd do everything in one shot since I need to go to an exhaust shop (like Midas) to have my Borla tips extended flush with my aftermarket rear bumper...they are currently about 2-3" sunken in.

 

Owning a set of these pipes I'd have to say that the build quality and fitment was great at least.

I can't really say about any power gains on these alone as I went straight from all stock to hks mufflers/topspeed y/megan b at the same time. But since then I have removed the hks mufflers cause I'm not sure it want to keep them or not.

After putting the stock mufflers back on and leaving the other 2 pipes there is still a slightly deeper note than totally stock. Still can't say if it's more the y-pipes or the megan b pipe that is making it sound better. Surely it would be even more defined and a bit deeper on a GS400 V8 and may be a consideration still even with negligible performance gains...

 

Thanks for the input! So, in other words does this item(s) replace the stock Y section or no?

 

It replaces the second Y section not the front Y section. It is a direct fit and will bolt on at the end of the front Y section after the center resonator or catalyst depending on year.

 

Yeah the car kinda has 2 y's one from the exhaust manifolds into the front mid-pipe/b-pipe/y-pipe/down-pipe/merge-pipe (seen it called all these things) and then there is the rear y-pipe that spilts back out the mufflers.

A couple weeks ago when I was taking off the HKS mufflers I snaped a pic while I had the car up on the lift. This may help visualize how the exhaust routes on the car.



And here is a link to my previous thread when I installed all the exhaust, there are many more various pics there.

https://www.clublexus.com/forums/gs-...pipe-pics.html

 

^

...hmm judging by your second and third pics it looks like they would flow a little better than stock...without the need for the large oem resonators and also, the "y" in the beginning looks a lot more gradual than the oem setup. What do you guys think?

 

Agreed with a couple reservations. The front Y shown for a GS300 uses stock pipe size so it probably works very similar to the stock pipe. The rear Y pipe shown fits both GS300s and 400s is larger size than stock and may lose low end power AND there is the question about the resonator contruction that I posted above. Someone that understands needs to look carefully INSIDE the resonators to determine if they are of good design otherwise they could easy be more restrictive than stock.

 

I'm thinking of getting the Megan downpipe as well but I'm not sure if the stock b pipe has a resonator or a cat in it. My GS is a 2000. I want to make sure I can still pass inspection here in NY with this installed. Some people on her say it will throw the CEL on, some say it won't. Someone please help!

 

From my situation after i upgraded the pipes from cat-back to 2.5", CEL is on all the time. scanned it yesterday and it was indicating that the cats were bad. also the secondary o2's.


Rock, i say go for it or get custom built. pretty much about the same price.

 

so no go for us GS4 guys? :/ no gains?