Is the IS250/350 true dual exhaust or just dual tailpipes

If dual exhaust where does it split, are there two mufflers, etc?

 

It is a Y shaped configuration.

 

Dunno what you mean by true dual exhaust...but it splits at the rear axle and has 2 mufflers.

 

Several days ago there was a post here (I can't find it, but I think it was from someone who worked at a Lexus dealer in Florida) to the effect that the exhaust headers from each side of the V6 were combined and then split, so more like an X configuration.

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. exhaust headers for each side of v-6 goes to one pipe, then just after rear axle pipe splits of to two mufflers one one each side.

 

because they have separate headers and O2 sensors etc which then join about midship for a common muffler then divide out to individual mufflers and tailpipes. The "X" type is a good description. Both cars are ULEVII compliant and best fuel efficiency in the Lexus lineup. All around state of the art engineering under the hood with excellent power to weight ratio.

 

Here's a picture.

 

that exhaust has to go! too much constriction!

 

I agree. Looking at the design, it is geared too much towards keeping the engine quiet and constrictive. It must be robbing the car of substantial horsepower (around 8-9 whp (11 - 12 HP at the crank) or so).

 

Anyone know how much the HK muffler will be? Also, any idea on the eta?

 

I believe it is around $600 (not installed) and it should be available by spring 2006.

Lex

 

Thanks again MR LEX. I wonder what kind of hp gain we can expect?

 

If I had to guess I'd say that 05RollaXRS is probably pretty close, 8-9 rwhp on the same dyno. I doubt you would feel it, but it's still fun to do. And besides, you might help the exhaust note.

 

That's what I was hoping for

Lex

 

LOL, I didn't know we had an exhaust note