RA40

iTrader: (6)

John,

Was curious how your exhaust header project is progressing?

Lexkost

[QUOTE]Originally posted by jbrady
[B]Since the stock LS400 exhaust system sucks... I decided to design a complete system from the cats back and keep the stock system intact in case I need to return the vehicle to stock. This will also allow me to remove the system (put the stock back on) and make jigs and send parts off to have custom pipes bent so I can build other copies for those interested. Obviously this is NOT the cheap way to do things but the end result should be very worthwhile.

I see your from Texas I don't know the smog laws there but in California you can change to high performance cats after the car has 60k( I have used them ,they have a screen in them instead of the pellets )and this causes them to be smaller (meaning the body size)and the increase in flow is great...........I myself have been investigating a system for my 96LS but I don't want it loud.I like what you have so far but I would like to change my cats also and make it all smog legal.I already have a place that can fab everything I need for the project.............Please keep us posted on your out come.

JBrady

Lexkost, there are at least 3 different catalyst designes. The OLD style, 1970s and some 1980s used the catalyzing pellets packet into a case. The exhaust had to force its way around the pellets and that produced high backpressure with bad engine power. The 2 main types in use today are 1) ceramic monolith and 2) metal core.

The monolith looks like square hole honeycomb and is a ceramic extrusion that has a large number of straight holes and they flow fairly well. Most aftermarket cats use this style. Performance varies greatly from worse than stock to similar and on vehicles with poor or undersized cats sometimes better.

The metal core design is the best flowing and most expensive. The metal core is used on my Lexus and I think all of the USA spec models. Anyone can check to see by looking inside their cat. Here is a link with more information and pictures... the cat information is at the end.

https://www.clublexus.com/forums/sho...hlight=exhaust

Here is a link with more information on my exhaust upgrade parts and recommendations:

https://www.clublexus.com/forums/sho...hlight=exhaust

Here is a link with info on the exhaust manifolds.

https://www.clublexus.com/forums/sho...hlight=exhaust

Bottom line, I doubt you will easily find a replacement cat that out flows your current cats. Remember, going to a larger case catalyst can lower velocity. You may wish to check out the header effort I have started. There will soon be a sign up for this here at Club Lexus but for now you can go to the following thread for technical information.

http://www.lextreme.com/forum/viewforum.php?f=27

JBrady

Sorry for the slow response to your question. I have had MANY distractions the past 2 months and haven't participated much on these forums and have not done my cat back yet even though I have all the parts.

As far as pricing goes that depends on what you want. If, like myself, you want to start at the catalyst outlet you will need flanges. Some say that these are easy to find but the largest 2 bolt flanges listed in most sites were 2.0" and that is not enough. You could cut your flanges off your existing pipes but they may be smaller than optimal also. I had custom flanges laser cut so the ones I have are expensive. I would have to charge $40 each unless I had a large order and even they it would be at least $30 each.

Most of the cars I have seen use about a foot of the stock pipe off the catalyst and slide larger pipe over that. From their back it is up to you again. Do you want the optimal mandrel bent parts? If so each bend is $10-15 and then they must be cut and welded together. If the cutting and welding is not done correctly you negate the value of the mandrel bends

Next come the merge areas. As outlined above I am going with the "dual Y pipe" or "long X" design. This requires 2 racing style Y pipe merges. If the Y pipe is not done correctly it will become a place for turbulance and will not help power... probably hurt power. The stock parts are ugly and restrictive but they do make for high velocity and that helps low RPM power/torque. True racing Y merges sell for about $100 each. These are better than the Dr.Gas Y pipes that sell for about the same. I may be able to get this price down if the demand volume is there.

So, as far as pricing, anyone interested please PM me with their specific goals and REALISTIC budget and I will try to help you choose the most effective parts for your budget. IMHO, the best bang for your buck would be to buy two Y pipes or one X pipe (must be properly made). Have a muffler shop replace the center section with these parts and a straight through 2.50" pipe. Make the pipe 2 feet long and it can be replaced later if desired with a resonator for reduced noise. Get rid of the silencers and plumb the dual pipes directly into the stock mufflers or run a pair of turbo mufflers. This should be worth 10-15rwhp.

At some point I may be able to offer a complete system done RIGHT but for now it must be a one on one custom design.

RA40

iTrader: (6)

Your posts and the resulting follow-up's on Lextreme about exhuasts has been very informative. I'm considering a run by Burns Stainless to see what they will ask for an exhaust system build.

www.burnsstainless.com

At minimal maybe some Y pipes to graft into the stock system and eliminate the silencers and center resonator.

JBrady

Burns is an excellent choice but VERY expensive. I have posted info and pictures from Burns many times. Expect to pay $220 to $250 for each Y pipe. Beautiful work but expensive. A full custom burns system would probably come in around $2000 but check with them and let us know. BTW, the mild steel Y pipes I have posted pictures of are $100 each.

blkvip

iTrader: (1)

post 29 and 30 were are the mufflers from im loveing themmmm? and im guessing its an axel looks they bolt up to the xpipe,which is what im looking to do for now

LEXUSA400

I do realize this thread is 100 years old but was wondering how the end result turned out?

I have a question too. On my '97 LS400, are there just the two catalytic converters on the manifolds? The next "box" after the "Y" is a resonator that kinda looks like a cat?
Has anyone done an exhaust cut out? Like a quiet single exhaust on the passenger side and an open cut out on the drivers side that can be controlled electrically or by a cable?

Would/could/should a single 3" exhaust be as quiet as the factory dual LS400 system? It would be nice to have both, war/peace.

Twista4004

I believe RadioKilla has a single pipe on his car. Not 100% it's his though. You might try to PM him. Yest this is a 3 month late reply but then again your post is 100 years after the thread died.

GR8TSCOT

iTrader: (1)

I had a '99 LS400 (totaled in an accident) and replaced it with a 2000 LS400 earlier this year. I put S&S headers in the '99 (see much earlier in this post), but they were meant for the GS/SC, and required exhaust pipe/cat surgery to get them to fit. Worth the price and the hassle, but they did not last.

When they cracked after 5 years, and S&S were out of business, I contacted Paul Prentis at PPE Headers in Tempe, AZ, who inherited the 1UZ-FE header jigs from S&S. They were using thicker-walled headers, and guaranteed that they wouldn't crack. To get headers to fit the LS, I ordered a set of stock LS headers from a friendly local dealer, sent them to Paul so that he could make up jigs for his custom headers, then returned the stock headers to the dealer, unused. As a result, I got a pair of headers that fit like a charm, and definitely added a solid 30 HP to the top end. I ended up ordering two sets: one for the '99, which I ordered in 2010, and the second earlier this year for my 2000. I have surprised a lot of vehicles with just the header replacement.

I tried other exhaust tricks:
- Eliminated the first set of silencers. This was a mistake, the car sounded just loud, not loud & nice. No faster than stock.
- Replaced the rear mufflers with L-Sportline mufflers. Looked stupid without the L-Sportline rear bumper (think ***** hanging down from short shorts), but did sound nice. No faster than stock.
- (with the S&S headers) Replaced the centre resonator / pipe with a larger diameter pipe, better Y pipe at the back and a higher-flow resonator: sounded nice, better top end (maybe 5-7 HP), but lost a noticeable amount of low-end torque.

In the end, the only things which made a noticeable difference to the performance were:
- S&S / PPE Headers
- K&N Air Filter
- Light-weight wheels: I have OZ Ultraleggera 17"x7" wheels which weigh 16 lbs. each, vs. about 25 lbs. for stock wheels. They are s-w-e-e-t after receiving a black chrome treatment from California Chrome Wheel.

Twista4004

1. How much were they shipped?

2. What was the turn around time?

3. Think they still have/make them?

4. Can I massage them onto a UCF 10/11? <---If previously answered, please don't flame

GR8TSCOT

iTrader: (1)

1. Price was about $600 with jet coating. Possibly a deal, since this was the second set I ordered from them (and I got them the stock headers so they could make the jigs)

2. Turnaround was about 4 weeks.

3. They absolutely still make them! I got my latest set in April.

4. No idea. Best bet would be to ship Paul a set of stock headers so that he can make up the jigs, although he may already have jigs for UCF10/11.

VanCityLS4

iTrader: (1)

Headers are the best bang for the buck upgrade for the 1uz. Too bad labour costs to get the parts installed would probably be more than the headers themselves.

How many hrs to re & re ? Pics ?

GR8TSCOT

iTrader: (1)

10 hours, $750 at my Lexus-certified mechanic.

PureDrifter

iTrader: (10)

idk about bang for the buck, but they're probably the only reasonably priced modification that nets solid power.

Labor is about 5-800 last i checked, but really depends on the shop.