JBrady

Silver, as you know the first pictur is of a Y pipe and the second and third are full duals with a crossover H pipe with a hefty pricetag of apx $2400.

I am interested in the Y pipe section. The picture is fuzzy so it is hard to tell but it looks like the end has a flange on it? If so, maybe this is for their parts to bolt up or maybe it is for a 1st generation LS400. Either way, can you quote a price and import proceedure? Are the pipe diameters given?

Thanks a lot.

v8huntr

lexus ls400 has 2-1-2 exhaust system. you'll need y-pipe and more. if you are making this system your self then use burns stainless steel for exhaust parts. make sure to use stainless steel pipes and mufflers. Burns have pre made y-pipe,90degree pipes and other pipes. hks makes nice universal stainless steel mufflers you can buy. hks is quite and it gives deep exhaust tones. borla xr1 street mufflers are also very nice ones. 3"inch system on lexus is not that bad and it'll give you extra room for future mods. burns stainless steels are the best of the best. i hope this helps.

p.s
stick with 304stainless. 321stainless might get too expensive. burns 304 stainless is still better then most of the other tuners use to make their exhaust systems.

www.burnsstainless.com

JBrady

I have reference Burns MANY times...

Stainless is best and is my choice but is NOT required. I ran a mild steel 3" turbo downpipe that I constructed out of mandrel bent tubing and a tig welder. It worked just fine. After 2 years of use I removed it and had it Jet Hot ceramic coated. I ran it another 3 years and sold it when I changed engines.

Mild steel actually has some benefits. MUCH easier to cut, fit and weld and of course CHEAPER... of course the ceramic coating nulifies that benefit.

JBrady

I found this Y-pipe on the C's website. Price is 98,000... yen = just over $800, all stainless, 60mm primaries (2.36") 75mm secondary (2.95")

It looks to fit a 1st gen car and deletes the center resonator. I don't know if they have one for other years or not... I don't speak/read Japanese. The C's site opens with a cutaway pic of a supercharged LS430 but I cannot find any more about it in the site. The only Celsior pics/info is 1st gen so I imagine they have 2nd and 3rd gen stuff too. Anyone read Japanese want to translate?

http://www.cs-comrade.co.jp/

I am guessing 5.5 liters, Eaton M112 supercharger, 480hp???

Although power is more and more becoming listed as Kilowatts (Kw) which 1 Kw = 1.34hp... 480Kw = 643hp!!!

SilverFlare

From the site , I think the compressor is for UCF10,11,20 only.
our 98 LS is UCF21, so the compressor is not gonna fit on our car plus from the site, I don't think they make supercharger for VVTi model, but I just wondering why they can make 5500cc supercharge system for LS430 since LS430 is also VVti model ??

I can see from there the Y pipe is for the 1st generation 98000yen, SLC which remove the speed limiter is 46800 yen and the square tail all stainless mufflers 348000 are for for 2nd 3rd generation celsior

Jbardy,
I don't understand why the Y pipe is cost that much? since u already removed the rear two mufflers, I think the air flow is always faster than any universal mufler, right? plus it also reduce the weight of car, I don't know about these, will the torque be affected, too? tks :eek:

JBrady

ALL of C's pricing is very high. Quality looks very good but at a cost.

Yes, the LS430 is V-V-T-i so you would think they could make it for the 98-00 models??? who knows.

Regarding the Y-pipe, it would cost me apx $600 to reproduce with quality Burns Stainless components... I think the 2.36" pipe is too big. I am slightly concerned that my 2.25 will drop very low torque slightly. 2.125 could be perfect. Stock is 1.95. All numbers are O.D. in inches.

When you say speed limiter are you refering to vehicle speed or engine RPM? I would like to rev to 6500-6800rpm.

Lvangundy

What's up with the dinky exhaust piping?

Jbrady - you've explained piping diameters and flow rates in other threads, but I don't get why keep basically the same size as stock piping for an exhaust mod?

Look at like american V8's, most of them don't use 2" piping. I know you know what you're talking about more than myself, but does such a small difference in piping do anything for performance?

Where's the dyno when you need it..

JBrady

Power curve. I want to retain low RPM power while increasing mid and high RPM power.

Too small a pipe (like stock) creates a restriction to high RPM flow/power.

Too large a pipe can reduce low RPM power by creating turbulence and reversion.

When you say American V8's I am assuming you are refering to the OHV engines such as the 5.0 Ford or 5.7 liter GM. These engine have 1 exhaust valve that has relatively high flow at low RPM. Our 4 liter engines have 2 exhaust valves and are actually less effective for low RPM power.

Just as all 4 liter engines do not perform the same... all like diameter exhaust systems do not perform the same. Obstructions, turbulence, boundary shear, reversion, pulse, harmonics etc all effect performance. You could use the exact same size (possibly slightly smaller) piping as stock and end up with a higher flowing system by removing restriction and improving transitions.

So, in the interest of more power I want a system that has more flow potential without hurting low RPM power.

When comparing pipe size it is the Outside Diameter (OD) of a pipe is what most people measure but it is the Inside Diameter (ID) that is what the gas flows through. ID is generally 1/8" less than OD.

My proposed size is 2.25" OD with a 2.125" ID.

The stock size is 50mm or 1.96" (OD) with a 1.835" ID.

The 2.25"OD pipe has 34% more internal flow area (cross section area) than the stock 50mm OD pipe. This should be sufficient to present no restriction of high RPM power without hurting low RPM power.

Lvangundy

Hmm..

I understand a little better now. thanks =)

This may explain my weird 'rev-return' probelm I have (never mentioned it previously).. after I rev the engine up on its return back to 600 idle RPM, it slows down at certain points before it hits idle. My guess this has something to do with my exhaust system since it's expelling gasses. You can hear a LOUD hissing noise when the engine slows (return from high rev) and I have yet to pinpoint where it's coming from. Either the cats or the rear mufflers.

Remember the manual specifies exhaust components replacement every 4 or 6 years.

Currently where the centor single resonator was I put 3" piping (from cats to Y) and the rest towards the rear end of the car is either 2.5" or 2 1/4". Maybe because of the piping size change more turbulence is created which may be the culprit of the strange return idle I'm having, plus loss of low end torque.

If there's any sense to this I will try to get my car to another shop (as the last one I took it to uses cheap piping I just know it) to have the sections made to all 2 1/4" from the cats back and if possible a more straightened path. Here is a picture of how it looks now.

SQ-LS

Hey Lee how much did that cost you to do?

JBrady

Hmmm... correct me if I am wrong but it looks like the system is stock from the cats to the Y merge then the center res was cut off and straight pipe welded in place. It looks slightly smaller than the straight section right after the flange. Maybe 2.5" before and 3" after? Anyway, after the flange and that 3" straight the shop fabricated a diverge Y section leading to the duals of ??? diameter? Anyway. For test purposes, I would unbolt the system from the center flange to the rear mufflers and see how the engine response with just the 1st Y pipe in place. This will help determine where you are creating low RPM problems. If it wakes up the low end you need to reduce the total volume of the remaining system. It can act like a big air spring and hurt low rpm flow. My guess is it helped high RPM flow as the parts seem OK from a flow perspective. Just the low RPM velocities are a problem.

If dropping the system cures your low end response you may get away with fabricating an anti-reversion chamber in the center straight section. First things first, see if you can test it as I suggest.

Lvangundy

Yes..let's confirm this..

From the stock cats until the point where they would have connected to the single center resonator- that piping is stock.

I left the stock butt (?)end connectors just so I could change it back to the old mufflers if needed. From there is the 3" pipe replacing the center resonator. After that is another set of stock connectors to those bent pipes which are either 2.5 or 2 1/4". Another stock connector is used to chain into the stock rear mufflers. something annoying I noticed when removing the centor resonator was that when the exhaust is cold and you give the car some gas, the exhaust makes that very loud tinging/rattly noise (the rattle sounds like a cheap ricer civic exhaust), but after it heats up it's alot deeper than stock especially around 2100RPM.

Loule- I'll tell you the cost, but you might want to take jbrady's advice if you are planning on something like this. If I were to have anything modified I would go with j's plan of the 2 1/4" piping all the way through. Anyway .. the cost total was roughly $120-175. I have all the recepts somewhere.

Just make sure you take it to a good shop as the place I took mine to get done was pretty flakey and ghetto. The prices would change every time I came back, I swear they use cheap piping and welding techniques.

JBrady

Lee,

The basic system looks OK although I am a bit concerned about the transistions. Using the stock flanges means that the ID would of the flange would be the same. So, the 3" pipe would have a sharp edged 2.4" hole at the flange and the rear 2.5 or 2.25 pipes would have a 1.9" flange at the hole. Sharp edge restrictions flow much less than a section of pipe with the same diameter. In other words it is probably better to use 2" pipe without a restriction than 2.5" with a 2" restriction.

Note my last sentence on my previous answer. An anti-reversion chamber at the Y junction could help with the low end power. I would suggest welding a 2.25" diameter pipe aprox 4" long at the actual junction of the 2 pipes from the cats. Make certain the inside flow area is smooth at this 3 pipe junction. Take a 12" section of 3" diamter pipe and swage one end down to 2.25" ID. Place that swaged end of the 3" diameter pipe over this 2.25" section so that most of the smaller pipe is inside the 3" pipe. Now, this is just an idea and I haven't actually studied the stock Y pipe as mine has a permanent heat shield.

Take a look at Fig. 11
http://patimg2.uspto.gov/.piw?docid=...S=PN/6,336,471

This will create a high velocity one way "valve" and the rest of the system will be responsible for maintaining low pressure.

SilverFlare

I found the pix of X pipe for 98-00 LS400

SilverFlare