Exhaust System for the LS400
08-23-02, 07:15 PM
#1
Lexus Champion
Thread Starter
Exhaust System for the LS400
Went to my local Lexus dealer and wandered through the shop during lunch. As many of you know I have started tinkering with my 99 LS400 and... well... once you start it is hard to stop 
Anyway, there was a GS400 on the lift as well as a copy of my 99 that was getting a complete new engine, the other was hydrolocked and broke a rod. Got a chance to really study the exhaust as the entire system was removed and set aside.
Conclusion: it looks like an entire cat back system is in order and I mean ENTIRE. The cats bolt directly to the headers and after that everything looks in need of improvement. Believe it or not I think the stock mufflers are probably the BEST part(s). The transition from the cats to the Y-pipe needs help. The Y in the Y-pipe is hidden from view by shielding but I highly doubt it is optimized. The first resonator is a problem. The reverse Y leading to the 2nd resonators is a problem. The 2nd resonators show heat discoloration usually indicative of a restriction. So, to do this right would take new plumbing from the cats to the stock mufflers.
Interestingly enough, it looks relatively easy to pull the stock parts off after the 1st resonator. This would give a good idea of potential gains (not to mention being LOUD). I may do this and drive to the track for testing I would love to see the faces on people as they hear an unmuffled high rpm 32 valve V8 sing!
Anyway, there was a GS400 on the lift as well as a copy of my 99 that was getting a complete new engine, the other was hydrolocked and broke a rod. Got a chance to really study the exhaust as the entire system was removed and set aside.
Conclusion: it looks like an entire cat back system is in order and I mean ENTIRE. The cats bolt directly to the headers and after that everything looks in need of improvement. Believe it or not I think the stock mufflers are probably the BEST part(s). The transition from the cats to the Y-pipe needs help. The Y in the Y-pipe is hidden from view by shielding but I highly doubt it is optimized. The first resonator is a problem. The reverse Y leading to the 2nd resonators is a problem. The 2nd resonators show heat discoloration usually indicative of a restriction. So, to do this right would take new plumbing from the cats to the stock mufflers.
Interestingly enough, it looks relatively easy to pull the stock parts off after the 1st resonator. This would give a good idea of potential gains (not to mention being LOUD). I may do this and drive to the track for testing
I would love to see the faces on people as they hear an unmuffled high rpm 32 valve V8 sing!
08-23-02, 07:23 PM
#2
Lexus Champion
Thread Starter
Oh yeah, the stock headers suck but that would be REAL hard to change. Mo tells me the engine needs to be pulled :eek:
Anyway, I mentioned the transition from the cats to the Y-pipe as being very strange and restrictive. I thought that may be the difference in the GS400s extra power. To my surprise the GS had a different transition but not anything worth power. The improvement looks to be in the 1st and 2nd stage of resonators and in the reverse Y section.
There are many pitfalls in building a new system but I may go for it. I will keep everyone posted especially if it looks like something I can reproduce and sell at a reasonable price. I am NOT in this market but have been in the past and since there is NOTHING available for our cars... maybe a few here will want this. I am guessing 15-20hp at a cost in the $1000 range. Let me know.
Anyway, I mentioned the transition from the cats to the Y-pipe as being very strange and restrictive. I thought that may be the difference in the GS400s extra power. To my surprise the GS had a different transition but not anything worth power. The improvement looks to be in the 1st and 2nd stage of resonators and in the reverse Y section.
There are many pitfalls in building a new system but I may go for it. I will keep everyone posted especially if it looks like something I can reproduce and sell at a reasonable price. I am NOT in this market but have been in the past and since there is NOTHING available for our cars... maybe a few here will want this. I am guessing 15-20hp at a cost in the $1000 range. Let me know.
Last edited by JBrady; 08-26-02 at 01:06 PM.
08-26-02, 02:02 PM
#3
Lexus Champion
Thread Starter
As it was a GREAT source of data for the HFIM (high flow intake mod) Pete's killer site has great exhaust mod information.
Here is a link showing the relative backpressure and parts for an SC400 that look nearly identical on our LS400s
http://www.users.bigpond.com/pgscott...asurements.htm
He also has exhaust sounds at the above site.
I am posting this stuff to get some feedback on any interest in building an exhaust for our cars... any comments?
Here is a link showing the relative backpressure and parts for an SC400 that look nearly identical on our LS400s
http://www.users.bigpond.com/pgscott...asurements.htm
He also has exhaust sounds at the above site.
I am posting this stuff to get some feedback on any interest in building an exhaust for our cars... any comments?
08-31-02, 12:40 AM
#4
Lexus Champion
Thread Starter
Apparently not even many people here at ClubLexus are interested in more power for their LS400s. In the interest of archived information... I have decided to go with an X pipe instead of a Y. For those interested check out the X and Y pipe sections of www.burnsstainless.com
After the X I will use a dual path resonator, see page 2 of the PDF link for Dynomax pt# 17280
http://www.dynomax.com/documents/ultrafloss_specs.pdf
After the X I will use a dual path resonator, see page 2 of the PDF link for Dynomax pt# 17280
http://www.dynomax.com/documents/ultrafloss_specs.pdf
08-31-02, 12:59 AM
#5
Search Function Inc.
Since you moved up to the '99 LS I kinda lost interest. If that thing would work with the 1st gen, then that would be pretty interestng. Also they were in the process tof making headers for the LS in australia after theyt completed the same project for SC. I have not heared about that thing since. I would imagine that replacing the headers on SC is the same as on LS so you need to talk to peeps in that forum who replaced their headers.
08-31-02, 12:35 PM
#6
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JBrady,
Please keep up the good work. You are the type of person going to make the LS in higher performance. You are doing a good job. I know you are doing as passion, not motivated by money.
Hey Retro. How are you?
I also have a passion for myself. I am doing some custom fab for the turbine housing. I am doing a twin T3 non-intercooling system for my car.
Brady, please keep us inform
dc
Please keep up the good work. You are the type of person going to make the LS in higher performance. You are doing a good job. I know you are doing as passion, not motivated by money.
Hey Retro. How are you?
I also have a passion for myself. I am doing some custom fab for the turbine housing. I am doing a twin T3 non-intercooling system for my car.
Brady, please keep us inform
dc
08-31-02, 01:46 PM
#7
Lexus Champion
Thread Starter
Retro, 1995-2000 year LS400 have identical exhaust systems, so, this will bolt in any of those cars. For the 90-94s it should work with very minor mods... maybe no mods! I will try to find out. But first...
Healerhand, thanks for the support. Do you have any pics on you progress with the TTs? When you say custom fab on the turbine housing... what are you doing? The wastegate area? Other? Let us know.
Healerhand, thanks for the support. Do you have any pics on you progress with the TTs? When you say custom fab on the turbine housing... what are you doing? The wastegate area? Other? Let us know.
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08-31-02, 04:33 PM
#8
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i just finished taking off the other resonator on my 92 ls and put 2 1/4" piping in. after i did that i have only been driving in heavy stop and go in town and so far i have 160 miles to a little under the half and 3/4 tank i was getting 150 over half a tank, but i am thinkin that it is becuase i have not had it on the freeway like i use to when i when to shool in long beach so its eating up gas
how is other peoples gas mileage
how is other peoples gas mileage
09-04-02, 02:10 PM
#9
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Jbrady,
Once i get my exhaust housing done. It will be taken to a muffler shop for minor fab work and it will be install. i will try to get some picture than. It will be few weeks.
dc
Once i get my exhaust housing done. It will be taken to a muffler shop for minor fab work and it will be install. i will try to get some picture than. It will be few weeks.
dc
09-06-02, 05:51 PM
#10
Lexus Champion
Thread Starter
Originally posted by VicFerrari
i just finished taking off the other resonator on my 92 ls and put 2 1/4" piping in. after i did that i have only been driving in heavy stop and go in town and so far i have 160 miles to a little under the half and 3/4 tank i was getting 150 over half a tank, but i am thinkin that it is becuase i have not had it on the freeway like i use to when i when to shool in long beach so its eating up gas
how is other peoples gas mileage
i just finished taking off the other resonator on my 92 ls and put 2 1/4" piping in. after i did that i have only been driving in heavy stop and go in town and so far i have 160 miles to a little under the half and 3/4 tank i was getting 150 over half a tank, but i am thinkin that it is becuase i have not had it on the freeway like i use to when i when to shool in long beach so its eating up gas
how is other peoples gas mileage
How does it sound and feel with the 2.25" pipes? Has the power changed? Are you getting any backfiring when cold like Ivan? Did you take off the two 2nd resonators and just now replaced the single center resonator? Pics?
09-07-02, 12:09 PM
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Jbrady,
Do u know any muffler that is quite and flow well? Since i am doing the exhuast system with my TT project. It will be 3" (2) all the way. i also would like to upgrade the muffler if possilbe.
Do u know any muffler that is quite and flow well? Since i am doing the exhuast system with my TT project. It will be 3" (2) all the way. i also would like to upgrade the muffler if possilbe.
09-09-02, 01:39 PM
#12
Lexus Champion
Thread Starter
HH,
3" exhaust and quite do not go hand in hand
I have always liked the sound of the Dynomax Super Turbo, not too loud and it flows well. You can buy it in up to 3" diameters. I am going to test the Bullit Pro Turbo which is claimed to flow and sound nearly the same but is built with stainless. I don't know how soon this will happen but I will report anything I find.
3" exhaust and quite do not go hand in hand
I have always liked the sound of the Dynomax Super Turbo, not too loud and it flows well. You can buy it in up to 3" diameters. I am going to test the Bullit Pro Turbo which is claimed to flow and sound nearly the same but is built with stainless. I don't know how soon this will happen but I will report anything I find.
09-09-02, 02:46 PM
#13
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I haven't noticed any power gain or loss I guess since I changed the piping and removed all the mufflers. If anything the changes may be in +/- 5 HP range so they aren't noticable.
I want my torque back! I have NONE of the line..there is no chirping and all I hear is a loud sucking noise then the engine revving..and I can't stand the 9 second 0-60. I'd really love some dyno time to mess with the air filter. I'd love to see proof of a conical filter gaining or losing power.
I'm geting the impression that removing parts and trying to drop lbs. off the car doesn't really make a huge difference. I think the test would be to run the car with 1 or 2 people besides the driver (about 350 lbs extra?) and get the closest 0-60 times as possible..then try removing 350 lbs somehow off the car. Maybe removing the seats and carpeting/insulation. Then see what the times are.
I want my torque back! I have NONE of the line..there is no chirping and all I hear is a loud sucking noise then the engine revving..and I can't stand the 9 second 0-60. I'd really love some dyno time to mess with the air filter. I'd love to see proof of a conical filter gaining or losing power.
I'm geting the impression that removing parts and trying to drop lbs. off the car doesn't really make a huge difference. I think the test would be to run the car with 1 or 2 people besides the driver (about 350 lbs extra?) and get the closest 0-60 times as possible..then try removing 350 lbs somehow off the car. Maybe removing the seats and carpeting/insulation. Then see what the times are.
Last edited by Lvangundy; 09-09-02 at 02:50 PM.
09-09-02, 03:06 PM
#14
Lexus Champion
Thread Starter
Lvan,
Your report is helpful and interesting but not scientific. Did you establish a solid, multiple and averaged 0-60 prior to mods? Using a stopwatch is also not accurate as so many things effect your timing. The best test is the local drag strip that gives a time slip including 60 foot et, 330 et, 660 et, 660 mph, 1000ft et, 1/4 et, 1/4 mph. Even so, multiple runs should be made and averaged, temperature and humidity should be noted.
For those without easy strip access I suggest the G-Tech. At $140 it will give repeatable, if not 1/4 exact, test times.
What your observations do support is just "opening up" the stock system does not produce the desired results. The main reason for my effort is to develope a high flow system that will be quiet but sound cool while producing more peak power without hurting low end power... maybe even improving it!
Your report is helpful and interesting but not scientific. Did you establish a solid, multiple and averaged 0-60 prior to mods? Using a stopwatch is also not accurate as so many things effect your timing. The best test is the local drag strip that gives a time slip including 60 foot et, 330 et, 660 et, 660 mph, 1000ft et, 1/4 et, 1/4 mph. Even so, multiple runs should be made and averaged, temperature and humidity should be noted.
For those without easy strip access I suggest the G-Tech. At $140 it will give repeatable, if not 1/4 exact, test times.
What your observations do support is just "opening up" the stock system does not produce the desired results. The main reason for my effort is to develope a high flow system that will be quiet but sound cool while producing more peak power without hurting low end power... maybe even improving it!
09-09-02, 03:26 PM
#15
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Yes! I very much agree.
The stopwatch and the times I got were the closest I could get from a 'street' sense. I figure if I can get to a strip sometime, averaging three runs would be a good number.
I am looking forward to some parts that are to be fabricated to actually give real numbers in performance, and not aimed at marketing for profit. Aftemarket Honda comes to mind..
I checked out the G-tech looks interesting. Wondering if anyone has one from the area..I'd love to borrow one. I'd go with a purchase but I'm somewhat short on $ right now.
Looking forward to all to come for the LS!
The stopwatch and the times I got were the closest I could get from a 'street' sense. I figure if I can get to a strip sometime, averaging three runs would be a good number.
I am looking forward to some parts that are to be fabricated to actually give real numbers in performance, and not aimed at marketing for profit. Aftemarket Honda comes to mind..
I checked out the G-tech looks interesting. Wondering if anyone has one from the area..I'd love to borrow one. I'd go with a purchase but I'm somewhat short on $ right now.
Looking forward to all to come for the LS!