Hi guyz, i have a cat back borla on my gs430, and i want to do the b pipe too, so any thoughts from where can i have them and what size should i go with if i want to costmize them.thanks in advance.

 

You have a catback Borla? I too have a Borla for my GS4 but it is only a rear section (or axle back) exhaust. I am not aware of Borla ever making a full catback setup. Any pics?

 

Are you are talking about the front Y pipe with the single resonator or the rear Y pipe and twin resonators?

I am constantly asked what to do about the front Y pipe and I have for some time now highly recommended keeping it STOCK. It works very well considering the options. The only reason to change the rear Y pipe would be to make the exhaust louder as there is no power gain with larger pipe or eliminated resonators.

Now, I have also suggested that a better part COULD be built but it is unlikely that a muffler shop or even a JDM manufacturer will build or offer one. I am about to build a test front Y pipe and rear Y pipe for my LS400. The 98-00 LS400 front Y pipe is VERY VERY close to the GS400 and 430. If my design goals prove to be an upgrade over stock I can change my recommendation on the GS4xx cars. That said it is STILL unlikely that a muffler shop could build what I have in mind. The goal is improve peak power and improve midrange power without loosing any noticable low end torque or engine responsiveness. The same goals that I had for the headers.

 

no, borla doesn't make them, thats why am asking from where can i buy them or make them. so i need to make the middl pipe if its going to make more HP

 

am talking about the middle pipe. if i make a bigger one, what size should i make and if i did it is going to make more HP, especaily if i took of the resonators

 

From what I understand you really won't see big gains (or any at all) by removing the resonators; it will just be louder. Deleting the cats is the biggest performance gain. You must also be careful of how large you go in terms of diameter of piping whether it be the mid-pipe or anything else...especially if you are staying with an NA application. If you go too large you will lose back pressure and lose a ton of torque (your car will feel slower).

If you are going for a FI application in the future then you can go with larger piping as the larger amount of air coming into the turbos/superchargers need a larger exhaust.

Larger piping will always be more beneficial with FI applications.

I would keep everything as is...but delete the cats and perhaps change the "Y" part of the Y-pipe and custom fit an "X" in there. Some say it improves both HP and TQ but mainly TQ.

GL!

 

thanks rock, i got the idea now. ok check this item and tell me what you think about it,is it going to do somthing in our cars?


http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT

 

I have it with my blitz. It made it much louder. Not too loud for me though. It fits perfect and is good quality for the price. I didn't notice too much of a power difference or anything. It's more for sound and looks IMO.

 

Rock, you got some of it right but a couple points need correction.

Backpressure is an exhaust system is BAD.
Larger pipe INCREASES backpressure at the VALVE at low-mid RPMs and is the reason for the loss not the opposite. I know this sounds counter intuitive but without velocity to keep gasses flowing AWAY from the engine the pressure which is PULSING pulses back at the engine pressurizing the ports hurting flow and contaminating the chambers for the next combustion cycle. People make the mistake of thinking in terms of constant flow instead of the way an engine actually works which is a series of pulses both pressure and accoustic.

The stock cats are flow VERY well. They also act like one way check valves that let the high pressure blowdown out but restrict the reverse pressure pulse back. This is why they help low-mid RPM power. They also work like resonators. Removing them will not help over all street performance. You may gain a couple horsepower at the very top of the RPM range but you will give up much more down low.

DO NOT change the stock Y. It works BETTER than MOST aftermarket X pipes.

DO NOT remove the stock cats. Performance will drop and sound bad.

 

Thanks for the correction J and for the education.

 

Thanks J for the helpfull info, but one thing i don't understand, is removing the resonators going to give you more power or how if i remove them going to give me down low RPM ans it is that good for our car or not?

 

No, removing the resonators will not give you more power high or low it will only make the car louder.

 

You should check out ebay I think there is a 304 stainless steel section for sale, check this link:

It is a whole system but he did have a center section for sale.

OH wow you already found him!!!

http://cgi.ebay.com/ebaymotors/LEXUS...#ht_2405wt_723