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Discussion Starter #1
So I opted for the cheaper route, instead of installing an entire new exhaust system I took your guys advice and just removed both resonators. I was wondering if anyone noticed lag when accelerating and if this is normal or can be adjusted?
 

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If you are talking about the delay when hiting the gas, it does happen. I spoke to my service guy and he said that It shouldn't happen again after I took it in. one week later it started up again. I think there are some posts about it.

Search is your friend.
 

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There shouldn't be any change in low-rpm torque or engine response if the stock tubing size was retained. If you went with a larger diameter tube to fill the space where #7 and #8 were, this will negatively affect flow and scavenging. If flow is reduced by using larger diameter tubing (or adding resistance in the system with diferent components), spent exhaust gases will not evacuate from the cylinders as effectively as in the stock setup. This will definitely affect low-rpm response.

Even though LR apparently spent considerable time tuning the exhaust system (and making it sound weak and anemic), it is very likely a very efficient configuration designed to maximize engine power across the rpm range while reducing sound levels. This has nothing to do with backpressure, which is something you do not want in an exhaust system. Although some backpressure exists in all exhaust systems, backpressure = restriction. Maximizing flow with straight-through mufflers and the use of an X-pipe (many high-efficiency mufflers have an X-pipe built in to their internal construction) will generally improve scavenging, which should at the very least retain stock power levels across the rpm range. It has been my experience that just adding an X-pipe to a stock dual exhaust system (assuming it didn't have one in the first place) will improve scavenging (opposing pulses through the X-pipe generate negative pressure which helps "pull" the alternate bank of exhaust gases through) and can result in a slight performance and mpg boost. However, any mpg improvement is often negated by the right foot pressing harder on the skinny pedal if for no other reason than to just feel that newfound power. And if it sounds better, too... well then all the more reason to press harder!
 

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Which model and year did you do this to?

2010 or prior, SC or HSE?

Still hoping someone has found some success tuning the exhaust note on the '10SC...
 

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Barmats,
You are correct in that the stock system is optimized over a wide range of flows and if you monkey around with it you may affect some part of the performance curve. At low flow levels a restriction is desirable thus Yamaha was playing around with EXUP valves for a while and I believe the Corvette and some other high performance cars use somethin' similar.

http://en.wikipedia.org/wiki/4-stroke_power_valve_system

By the way, doesn't the '10 have a speaker system to make the exhaust sound more enticing? If you could just figure out how to increase the sound from that...voila!
 

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The "speaker system" on the 2010 is arse. I dread to think how sad the exhaust note would sound without it, as it’s so anemic even with it.

You can buy products that amplify the sound of the engine through the car stereo, but these are designed for people with 1.2l Ford Fiesta’s who want them to sound like V8’s - ironic that our V8 sounds like a 1.2L Ford Fiesta...
 

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Discussion Starter #8
Barmats said:
There shouldn't be any change in low-rpm torque or engine response if the stock tubing size was retained. If you went with a larger diameter tube to fill the space where #7 and #8 were, this will negatively affect flow and scavenging. If flow is reduced by using larger diameter tubing (or adding resistance in the system with diferent components), spent exhaust gases will not evacuate from the cylinders as effectively as in the stock setup. This will definitely affect low-rpm response.

Even though LR apparently spent considerable time tuning the exhaust system (and making it sound weak and anemic), it is very likely a very efficient configuration designed to maximize engine power across the rpm range while reducing sound levels. This has nothing to do with backpressure, which is something you do not want in an exhaust system. Although some backpressure exists in all exhaust systems, backpressure = restriction. Maximizing flow with straight-through mufflers and the use of an X-pipe (many high-efficiency mufflers have an X-pipe built in to their internal construction) will generally improve scavenging, which should at the very least retain stock power levels across the rpm range. It has been my experience that just adding an X-pipe to a stock dual exhaust system (assuming it didn't have one in the first place) will improve scavenging (opposing pulses through the X-pipe generate negative pressure which helps "pull" the alternate bank of exhaust gases through) and can result in a slight performance and mpg boost. However, any mpg improvement is often negated by the right foot pressing harder on the skinny pedal if for no other reason than to just feel that newfound power. And if it sounds better, too... well then all the more reason to press harder!
I do experience lag at low RPM's and I believe my mechanic simply added a straight pipe where the muffler originally belonged. Will this have produce problems with my engine in the future??
 

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It shouldn't cause engine problems, but may indeed be the reason you've lost a bit of low-end grunt. If you can get under the vehicle and measure the outside diameter of the stock pipe, then compare it to the newly-added pipe, that should tell you if a larger diameter pipe was added. If it was, I would take it back and have them replace it with the stock diameter size.

You could also ask the mechanic what size pipe he used, but he may not know, or may tell you what he thinks you want to hear. Especially if you tell him why you're asking.
 

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Discussion Starter #10
Barmats said:
It shouldn't cause engine problems, but may indeed be the reason you've lost a bit of low-end grunt. If you can get under the vehicle and measure the outside diameter of the stock pipe, then compare it to the newly-added pipe, that should tell you if a larger diameter pipe was added. If it was, I would take it back and have them replace it with the stock diameter size.

You could also ask the mechanic what size pipe he used, but he may not know, or may tell you what he thinks you want to hear. Especially if you tell him why you're asking.
lets say I just decide to install two aftermarket mufflers instead, will i still get that same raw sound and will this lag still occur?
 

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FTD.

Think of your situation like this-by reducing back pressure in deleting two resonators, there is no consequent breathing improvement on the intake side as well !

By installing a proper cat~back exhaust system, a balance will need to be made in fine tuning the size of your replacement exhaust mufflers to result in laminar flow characteristics and deafening or otherwise sounds you desire ? Some of us mates down under refer to this loud experience as "Full Noise" or "Fully Sic Bro".

The same deep raw sound can be achieved by installing two separate big bore straight through mufflers, with a decent intake filter to eliminate the lag effect.

Cheerio,


Vinniman
'88 Highline
Perth, W.A.
 

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Could be a throttle thing, too. My '06 needed some adjustment to the (silly) fly by wire throttle in order to get it to respond more fluidly.
 
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