LOTC

After one day of test driving to L.A for 25miles, the 3rd setup seemed like it gained a incy bit of power, but after a while the airbox got pretty hot and it raised the temperature of the air inside. So this design was a no go. On the way back from L.A with just the HKS intake and heat shield, the car felt stronger than setup #3, but this was coming home at night, so it might of been the cold air, but I still believe setup #2 with just the HKS intake and Heat shield got just a little more than setup #3 with the HKS intake, cold airbox, and heat shield.

So when I got home I decided to make another setup with the HKS intake, heat shield, stock air duct with some extra piping. I carved out the shape of the piping in the heat shield so it can extend all the way to the HKS intake.

here is a pic of the new setup I made

LOTC

here is another view.

Hope this setup works better

JBrady

Tom, I researched the Dynomax SS Ultraflow mufflers some time back and went back to double check my memory. Here is the spec pdf page from Dynomax http://www.dynomax.com/documents/ultrafloss_specs.pdf
I do not see any dual-2.25-into-single-3.00. I do see part #s 17519 which is a dual-2.5-into-single-3.0 as is 17273. Nowhere have I seen the internal design being an actual Y-merge and I had called a couple muffler manufactureres (some time ago, thought Dynomax was one) and was told it did NOT have that design. Yes, they are straight through but on the duals they have a small plenum chamber. Again, if you have specs that say otherwise I would like to know as I would probably use ONE as the diverging Y section after the first Y into 3 inch center.

Burns custom builds the Y-pipes in almost any size combination requested. Also, on a Y pipe, the area that the 2 pipes merge into is typically smaller than the single outlet size. This creates a venturi that maximizes velocity and scavenging.

I agree that building a quiet, high flow system that maximizes the full power range is the goal. I am just sceptical of the internal design of the mufflers you list. If they are as you say it should work fine. If not, maybe their is a market for such a product?

Lextreme

Eric,

The SRT have a very similar setup as yours for the IS300. I think you should cover the inlet air. The angle of the air entering the intake is at 90 degrees. At this Angle, this will cause some turbinlet (spelling) Block it off and you should notice a better performance, or move the MAF few inches.

TomWahjudi

John,

Sorry, I looked up the wrong thing. According to JEG'S catalog, aluminized Magnaflow p/n 642-12278 (basically just 12278 for Magnaflow's internal p/n) has 3" single in/2.25" dual out (it is available in SS polished Magnaflow). As far as the design inside, I will have to stop by JEG'S to check it out. Remember that this is not UltraFlo SS, but Magnaflow (different company, not Dynomax) instead. My apology if I had lead you into thinking that it was made by Dynomax.

The URLs:

http://www.magnaflow.com/02product/universal/oval.htm <--- for aluminized
http://www.magnaflow.com/02product/ss.htm <--- for SS

Scroll down to 5x8 mufflers.

They are 24" long total, the case is 18" long. I still have to get some measurement to see if two of these will fit in the center tunnel, combined they are 4ft long. The aluminized ones are about $20 cheaper on average. So, for 4 mufflers, that's about $80 in savings.

JBrady

Tom, good information. I just contacted Magnaflow and they sent me a PDF engineering diagram of one of their single-in-dual-out mufflers. Very nice design, well engineered. However, they do not have a true scavenging Y-pipe. There is a Y area inside the muffler and it is of good basic design but will not perform the same function of a scavenging Y or X section.

As the exhaust travels down the pipe, the mass flow has thermal, inertial and accoustic energy. If this flow meets a plenum area (larger than the feed) it creates a reversion wave, the flow is disrupted and inertial energy is lost. Think of a siphon. As the fluid moves through the tube it pulls more from the feed end. Once it spills into a bucket it looses this energy. You can create a second siphon from the bucket but it will not have any effect on the first siphon. Now, with a closed system using compressable gas, this is more of a spring effect with the size and shape of any intersection effecting the flow from plus to minus. If the intersection is a scavenging merge like a burns X or Y you can actually increase the "pull" at the feed. If it is a plenum the pull decreases. The larger the plenum the lower any pull effect. Also, as the pull is decreased the reversion wave can actually increase pressure at the feed end. An X or Y intersection can actually accelerate the flow without creating backpressure or the reversion wave.

This is a simplistic explanation of why too large of pipe diameter hurts low speed gas flow (and power/torque).

So, IMO, your design will flow fine but will not perform as well as a proper X or Y. Burns charges more or less the same for one X pipe or 2 Y pipes (they make the X by combining 2 Ys). The X that Eric is using is much better than most inexpesive X pipes I have seen. The X pipe that Dr.Gas sells is of a different design and the same can be bought from http://www.stainlessworks.net/ although I have a feeling the Burns design is superior. But, we are definitely getting into the area of diminishing returns. The part Eric is using should work just fine (mild steel though). Using that X with a dual pass straight through resonator OR a Y pipe into a single then another Y pipe should yield the best results. Lots to consider or just go for it an hope... your choice.

Lvangundy

Jbrady -

Earlier in this thread 2.25" muffler inlets and 3" outlets were mentioned. Doesn't this defeat the attempt to keep the 'plenum' area the same size throughout the system to reduce disruptions in the airflow?

Shouldn't a properly designed system (assuming 2.25" is PERFECT for the LS) be the same size through the ENTIRE exhaust system? To keep smog certified, a Y-pipe (1in to 2 out) from the resonator (also 2.25") should extend back on separate pipes to 2 dynomax (or whatever) mufflers which have 2.25" inlets, internal piping and outlets. Does any muffler company make a 2.25" inlet, internal and outlets?

No jumps from 2.25 to 3" right? The measurements you took showed the stock 1998-2000 system to jump around very much in several different areas.

Along the exit line does backpressure and airflow fluctuation matter at the END of the 'tunnel' so to speak? As in, should the tips also be 2.25? Or doesit not matter at the exit?

LOTC

I will have some craapy sound clips of the setup later tonight. lol...

Lvangundy

Cool. Can't wait.

'I've been reading reviews of the dynomax super turbo muffler from several sites and nobody seems to think it sounds good.. Even less say it does something for performance!

I wonder how those mufflers sound on the LS. I want a deep tone, but I don't think the dynomax's are going to get me that sound.

LOTC

Well for some reason my car whines like I have a mini supercharger and people look at me all weird at stoplights. but I guess it is kind of a good thing to have that sound. But I dont know if you will hear the whine because I am going to record the sound clip from my digi cam and not a camcorder, since I do not have a digi camcorder. I will do the best I can.

TomWahjudi

Lvangundy,

This is twin 2.25" into 3" which is okay since the cross sectional areas of two 2.25" diameter pipes and one 3" diameter pipe are close. Actually if we can find 2.125" (2 1/8") diameter twin pipe the areas are even closer, but 2.125" pipe is not easy to find.

There are plenty of mufflers out there with 2.25" inlet/outlet. From single/single to dual/dual. Jump from single 2.25" to single 3" will be somewhat bad especially if you don't have smooth, gradual transition.

I will say tips don't really affect overall exhaust performance as long as you don't put things like louvers or smaller ID tip than the rest.


All,

I found out that Dr. Gas or Stainless Works X-pipe already cost the same as what Eric's setup did. And to add insult to injury, ONE Ultra Flo 2.25" dual in/dual out muffler costs ALSO the same as what Eric's setup did. Add two end mufflers, piping, hardware, labor and my concept ends up not worth it Maybe I'll just keep the exhaust on this thing stock for now

Lvangundy

I know..

What's up with the flow rate on the Dynomax Super turbo and the Ultra flows?

The super turbo is 400 CFM and the ultra flow is 1000CFM. I thought the super turbo would be a higher rating. Also according to their site the LS (based on their 2.2x170HP for first gen) only needs about 300CFM flow.

Ultra flows run from $60-$160each . Super turbos are under $50 online.

TomWahjudi

Ultra Flo = straight thru. Basically a straight pipe perforated and surrounded by packing material.

Super Turbo = baffled or chambered. Order a Jeg's catalog and you can see the difference.

I don't know how to explain about 1UZ-FE only needing 300cfm. It must be connected to pressure loss and probably some other parameters.

LOTC

sound clips can be heard here

https://www.clublexus.com/forums/sho...threadid=77011

JBrady

Lee, some of your questions have already been answered. Let me add some more. The stock system has TWO Y-pipes. A converging Y from the 2 cat exit pipes and a diverging Y from the resonator outlet. I would not call 2.25" "perfect" but more like the best compromise of comercially available pipe size.

The cats themselves act like plenums. By building a high flow system after the cats you reduce the restriction that the cats place one the manifolds. The 2.25" sizing is hoped to provide a reduction of backressure while maintaining high gas velocity. The converging Y is designed to maintain the enertia and velocity and merge both columns of gas into 1 going through the 3 inch center section. This section will contain a 3" ID straight through resonator. The combined length of the gas column is a mass moving away from the engine. This is designed to prevent reversion and assist in scavenging from the catalyst outlets. This drops the pressure at the catalyst inlet and reduces reversion within the header manifolds.

In order to use a dual outlet exhaust, there must be a diverging Y pipe. If this Y maintains velocity and inertia the effect is enhanced. If this section has a plenum the gass column looses its enertia. A diverging Y and converging Y are of slightly different designs but the factory diverge is terrible. Most muffler shop sections are for fitment only and pay little attention to function.

In terms of flow, the Dynomax page is using an internal calculation to help people size the muffler to their power needs. You should use engine HP not RWHP for this calculation. On my 300hp engine this means I need 660 (Dynomax rating) to prevent power loss. Now, NONE of the Superturbos can flow this much. But ALL of the Superturbos in 2.25, 2.5 and 3.0 size outflow the stock mufflers considerably. So, this doesn't mean it will stop your engine from running... rather that some power will be consumed by the backpressure. The Superturbos ARE fairly quiet and flow well for the decibel level. On 5.0 Mustangs they were always my favorite sounding muffler as they were mellow yet strong sounding without any rasp. A straight through design will flow much more than the chambered Superturbos but will be louder. BTW, don't forget, for the Dynomax power numbers the left number is the single muffler flow and the right is what 2 in a dual system will support. The best dual 2.25" are only 368, the best dual 2.5s are 384... both are way short of the 660 needed for my mild modded engine and I am guessing 320hp to be a better number and that would be 704.

Tom, I understand, this stuff is NOT cheap. After futher research I am convinced that the Y pipe design is better than the X. I see dual 2.25s from the cats into a 2.25-3.00" merge Y pipe, 3 inch ID center Magnaflow, diverging Y with a pressure valve. When low speed the valve is closed routing all gasses through one stock muffler. When open it will allow gas to exit a high flow section. I may try different size high flow sections from 2.25 to 3". This means I need two - flanges (having cut now) two - o2 bungs, one - converge Y, one 3" Magnaflow, one diverge Y, one pressure valve, one high flow muffler, and of course the relative piping between them. I will initially do it in mild steel with crush bends to gauge cost effectiveness. If it all proves out as planned I will replace the mild steel with stainless mandrel formed sections. Prototype cost should be around $500. Too much? To each their own.