Why no dual exhaust?
#16
You got to figure out why you want a dual exhaust. Are we talking about looks? For a dual exhaust to work you have to have dual exhaust manifold from the engine down the midpipe into two cat converters, two mufflers and then two tailpipes.
I have another car which came with one exhaust. I installed a dual exhaust on that car for looks. Yeah the back pressure is much less because of more area for exhaust gas to come out but I believe the benefit is minimal.
I have another car which came with one exhaust. I installed a dual exhaust on that car for looks. Yeah the back pressure is much less because of more area for exhaust gas to come out but I believe the benefit is minimal.
#17
You got to figure out why you want a dual exhaust. Are we talking about looks? For a dual exhaust to work you have to have dual exhaust manifold from the engine down the midpipe into two cat converters, two mufflers and then two tailpipes.
I have another car which came with one exhaust. I installed a dual exhaust on that car for looks. Yeah the back pressure is much less because of more area for exhaust gas to come out but I believe the benefit is minimal.
I have another car which came with one exhaust. I installed a dual exhaust on that car for looks. Yeah the back pressure is much less because of more area for exhaust gas to come out but I believe the benefit is minimal.
#18
Driver
Thread Starter
It's more of a looks thing then performance. The 350 is already a fairly high performance vehicle. (AT least compared to it's MDX counterpart). I'm not buying it's a cost thing. I was behind a Hyundai Santa Fe coming in to work this morning. It had duals but a 50K vehicle doesn't because it would cost more? That kind of reasoning defies logic.
Last edited by TomT127; 02-23-12 at 07:37 AM.
#19
I would think that Lexus marketing would figure that it makes near zero difference in sales as far as having dual exhausts. The engineers may figure a 5-10 HP difference is not needed or significant, and the accountants may figure that it indeed costs more to produce. Thus, no dual exhaust on these particular Lexus models.
Or it maybe as simple as women could care less if a vehicle has dual exhausts while men do like the looks moreso. Thus, still no dual exhausts for these models.
Or it maybe as simple as women could care less if a vehicle has dual exhausts while men do like the looks moreso. Thus, still no dual exhausts for these models.
#20
It's more of a looks thing then performance. The 350 is already a fairly high performance vehicle. (AT least compared to it's MDX counterpart). I'm not buying it's a cost thing. I was behind a Hyundai Santa Fe coming in to work this morning. It had duals but a 50K vehicle doesn't because it would cost more? That kind of reasoning defies logic.
You build a vehicle to a price point or you price yourself out of the market you are aiming for. A person shopping for a Hyundai Santa Fe is most likely not going to be going down the street to compare it to an RX. Two different types of buyers.
#22
Driver
Thread Starter
The RX 350 is already "sporty". At least compared to the SUV's we have owned in the past. Just think duals would improve it's sporty look. And I'm not trying to compare the RX to the Santa Fe, just pointing out if a lesser quality vehicle can have duals then it's not a matter of cost.
Obviously duals were not a deal breaker or we would not have purchased it. Just think there is always room for improvement and that would be one without raising the price much.
Obviously duals were not a deal breaker or we would not have purchased it. Just think there is always room for improvement and that would be one without raising the price much.
#23
No, I don't play soccer!
Um, I like the look of dual exhaust. The LS is the best IMO. But I also appreciate that I don't have to clean it Probably doesn't make sense to have it on the hybrid anyway.
#25
I do not know what Lexus engineers were thinking, but for me a lack of a true dual exhaust is stopping me from upgrading my RX!
Some more horsepower and better fuel mileage (which is fairly dismal in the RX) would be a welcome thing.
Some more horsepower and better fuel mileage (which is fairly dismal in the RX) would be a welcome thing.
#26
You would be looking at a complete redesign of the exhaust manifold, ECU mapping as well as engine placement to go a TRUE dual exhaust. Any improvement in HP (which would be minimal at best) and fuel economy (again minimal) would be negated by the increased retail price as well as future replacement costs of not one, but tow headers, downpipes, and potential catalytic converters depending on what the EPA would call for in certain states. An extra gear in the transmission would be the best solution and if you are looking for a dual look then just buy an aftermarket kit and gain a few HP.
#27
As far as having to redesign exhaust manifolds, et cetera, to be able to have dual exhausts, we know that the V6 Toyota Venza has dual exhaust outlets. Isn't this vehicle essentially the same vehicle under the sheet metal just like the third gen RX? Of course, the Toyota Highlander only has a single exhaust, it's a noticeable one, but nevertheless, it is a single exhaust. But as far as the Lexus lineup, I believe all of their vehicles, except for the two hybrid sedans and the RX, have the dual exhausts . So I say, why not the RX series??
P.S. I'm actually not sure that dual exhausts would look right on the current RX series, though, with the way the bumper is designed. Just my two cents!
P.S. I'm actually not sure that dual exhausts would look right on the current RX series, though, with the way the bumper is designed. Just my two cents!
#28
There are dual "exit" exhausts which are the result of a split at the back of the resonator (these are more of a muffler than anything) and some are called "Cat-Backs" since they emerge after the catalytic converter (as to not interfere with the factory emmissions which would be a bad thing for state inspections); or they can just have an extra pipe coming out of the muffler as an appearance piece and finally there are true dual exhausts which are the result of exhaust manifolds right from the engine having evenly split the number of cylinders and the system running all the way back each having their own parts and not sharing anything. The Venza is a combo and not a true dual. As you can see in the diagram for a 2009 Venza it splits the cylinders as all 6 cylinder engines do then comes together to share the pathway back towards the muffler followed by an extra exhaust tip tapped into the muffler - this is not a true dual exhaust. True duals ARE possible on 6 cylinder engines since each side of the engine shares 3 cylinders but it is a rare occurrence and is practiced more on 8+ cylinder motors which are more prone to high horsepower needs and racing applications.
Manifolds (handle 3 cylinders on each side)
The rest of it...
I share your opinion on the dual perhaps not being the best fir for the current RX design. I like mine hidden.
Hope this helps.
#29
You would be looking at a complete redesign of the exhaust manifold, ECU mapping as well as engine placement to go a TRUE dual exhaust. Any improvement in HP (which would be minimal at best) and fuel economy (again minimal) would be negated by the increased retail price as well as future replacement costs of not one, but tow headers, downpipes, and potential catalytic converters depending on what the EPA would call for in certain states. An extra gear in the transmission would be the best solution and if you are looking for a dual look then just buy an aftermarket kit and gain a few HP.
Some of you can claim no performance increase. I call B.S. on that one. Go out, tape a ping pong ball in your current exhaust, and drive your RX on the highway and tell me how well it runs! Then come back and claim exhaust restriction is not robbing you of any power!
#30
Careful what you claim. Here are the specs on the Venza with dual exhaust:
3.5-Liter V6 Double Overhead Cam (DOHC) 24-Valve with Dual Variable Valve Timing with intelligence (VVT-i); 268 hp @ 6200 rpm, 246 lb.-ft. @ 4700 rpm
Here are the specs on the RX 350 with 'single' exhaust:
Horsepower at RPM 270 hp @ 6,200 RPM
It's two horsepower more, not a lot I concede but still more and only one exhaust. But I'm willing to bet the diameter is larger. The RX mileage is rated at 18/25/21 and the Venza with the same size engine lists 19/26. The RX is considerably heavier at 4178 curb weight FWD, and the Venza at 3870 curb weight.
Bottom line is performance is compatible. This was off both web sites today. The weight of a ping pong ball was not given.
3.5-Liter V6 Double Overhead Cam (DOHC) 24-Valve with Dual Variable Valve Timing with intelligence (VVT-i); 268 hp @ 6200 rpm, 246 lb.-ft. @ 4700 rpm
Here are the specs on the RX 350 with 'single' exhaust:
Horsepower at RPM 270 hp @ 6,200 RPM
It's two horsepower more, not a lot I concede but still more and only one exhaust. But I'm willing to bet the diameter is larger. The RX mileage is rated at 18/25/21 and the Venza with the same size engine lists 19/26. The RX is considerably heavier at 4178 curb weight FWD, and the Venza at 3870 curb weight.
Bottom line is performance is compatible. This was off both web sites today. The weight of a ping pong ball was not given.
Last edited by Cruiter; 04-28-12 at 06:38 AM. Reason: additional info