Custom Exhaust, just want to see what people have done Options

[r_towle]

If you are planning on a custom exhaust system while retaining the stock HE's you need to measure the length of the HE's primaries and try to add length to the short ones and match all four before the muffler.

The Bursch muffler with its collector attempts to do just this.
Any bolt on solution that does not match the primaries does work, but not optimal.

If you look at what Foley has done, this is a tuned setup specifically designed to scavange in the best possible way with the 4-2-1 setup.

Notice the 4-2-1 setup uses opposing cylinders and scavanges based upon the timing of each combustion event. This is critical...you want to use the combustion event timing to increase scanvanging.

The HE's dont do this anywhere. They run 4 unequal pipes to the muffler...again Bursch tries to do this with the collector.
The Stock 2.0 liter muffler does this within the muffler itself, but it also not optimal.

Old school drag racers (VW motors) used just 4 pipes hanging in the wind, about 1 foot long each. That worked but many people learned about scavanging and rapidly changed to a different design.
The type one systems, and any drag racing header (4-1) is designed for WOT only..the rest of the range of operation does suffer.
the 4-2-1 system is really the best design for smooth power throughout the range of performance and driving.

Rich

[Jake Raby]

The Supertrapp has never impressed me. When they quiet the engine enough to justify them they kill torque and limit RPM range.

I did a study on this in 2002 for another company and the results were as much as a 22% reduction in overall performance and as much as a 45 degree increase in CHT due to the restricted thermals.

Until you experience one of these directly compared to something more superior it seems like its not that bad... I knew they sucked since 1993 when I used one in my sandrail and could no longer climb "comp hill" in 4th gear. I removed it and went back to the previous muffler and my power came right back.

[KaptKaos]

I just got a eurorace 4 into 1. What should I stick on the end of it? I was thinking a supertrap, but........

[Chris Hamilton]

The Supertrapp has never impressed me. When they quiet the engine enough to justify them they kill torque and limit RPM range.

I did a study on this in 2002 for another company and the results were as much as a 22% reduction in overall performance and as much as a 45 degree increase in CHT due to the restricted thermals.

Until you experience one of these directly compared to something more superior it seems like its not that bad... I knew they sucked since 1993 when I used one in my sandrail and could no longer climb "comp hill" in 4th gear. I removed it and went back to the previous muffler and my power came right back.

Can you post some details?

[Jake Raby]

I will email the company I did the work for to see if they mind me posting it- they paid for the work to be done but that was almost 7 years ago.

[Chris Hamilton]

I will email the company I did the work for to see if they mind me posting it- they paid for the work to be done but that was almost 7 years ago.

Have you heard of Jay Ivey? it's odd that he puts them on his customers race engines if they're such poor performers.

[turnaround89]

I may not have posted this but i don't plan on using the heat exchangers, Ill only be driving the car in the summer on the nicest of days. too much rust work that i had to do to go and blow it by driving in snow or even rain!!

How does the exhaust system change now without the heat exchangers? All the heating stuff will be removed from the car

[r_towle]

Well, you need a header.

4-1 is easier to build and/or easier to find used, probably the cheapest bet.

For a 4-2-1 you need to call Chris Foley and step up to that system.

If you plan to fabricate the system yourself, you should probably do some general reading on how to build a header, what primaries are, how to measure these, routing etc.

This is information that people have obtained through trial and error in what is often called R&D and its not given away freely in any business manufacturing anything that they sell.

I always chuckle when people are mad that vendors or manufacturers wont share the information on how to make a product and the key decisions behind the design of a product...that information costs money.

I suspect that no one would ever flat out ask a manufacturer of microchips or software or rocket how they are built...basically you would never expect them to share that information.

Reverse engineering has its place and if you can get your hands on a header that someone loans to you, go for it, copy that persons work.
Its not ethical, its not always legal, but its done all the time. Big firms do it all the time but they BUY the product to test it and reverse engineer it.

The key things you need to read up on.
Volumetric efficiency
Tubing size and how it affects are speed and volume.
Thermo Dynamics and the behavior of exhaust gases
Scavenge based systems
Back pressure
Muffler design and baffling.

This information is the basics and no one will step up to teach you the basics, you need to learn this stuff first.

I suspect that once you are honing in on a specific design with specific questions, Jake, Chris, and others will respond.
They just dont have the time to teach the basics that they spent years to learn themselves...

Specific questions, specific ideas that may be a tweak on an exiting design will always spur healthy debate.

So, I advise you to re-state your question and educate yourself enough to pose some questions that may be answerable.

Rich

[turnaround89]

I totally understand that a company won't release info about a product, if they did the company wouldn't exist to long. Thanks for the help. Ill do some research and start asking some questions along the way.

[Jake Raby]

I will email the company I did the work for to see if they mind me posting it- they paid for the work to be done but that was almost 7 years ago.

Have you heard of Jay Ivey? it's odd that he puts them on his customers race engines if they're such poor performers.

Perhaps he has never tested them comparatively, OR perhaps they work better than any other arrangement he has used. OR perhaps he has to use them to meet Db restrictions at some tracks and they work better at that Db level than anything else.

There are times when people make decisions based on things other than performance, even in racing.. weight and fitting challenges are just a couple. The company I did the testing for HAD to use them as they were recognized as a spark arrestor and where their engines were applied that was mandated by the USFS.

I emailed the company that I did the work for and they replied saying they don't care if we share the info. I'll do my best to capture some of the data and post it on my forums sometime in the next week.

[CliffBraun]

I will email the company I did the work for to see if they mind me posting it- they paid for the work to be done but that was almost 7 years ago.

Have you heard of Jay Ivey? it's odd that he puts them on his customers race engines if they're such poor performers.

Perhaps he has never tested them comparatively, OR perhaps they work better than any other arrangement he has used. OR perhaps he has to use them to meet Db restrictions at some tracks and they work better at that Db level than anything else.

There are times when people make decisions based on things other than performance, even in racing.. weight and fitting challenges are just a couple. The company I did the testing for HAD to use them as they were recognized as a spark arrestor and where their engines were applied that was mandated by the USFS.

I emailed the company that I did the work for and they replied saying they don't care if we share the info. I'll do my best to capture some of the data and post it on my forums sometime in the next week.

Thanks Jake. Some real numbers will be nice. I've only compared my supertrapp to stock exhaust and it's certainly an improvement in performance there.

One thing I would keep in mind is that you can turn a supertrapp into what's effectively an open pipe with the right number of plates. I have a friend who's got around 20 on one of his bikes, still does a fair bit of noise suppression.

[Jake Raby]

Thanks Jake. Some real numbers will be nice. I've only compared my supertrapp to stock exhaust and it's certainly an improvement in performance there.

That doesn't take much at all... BUT it actually may be a loss of performance, its just boosting the torque at a very low RPM and it feels faster for enough of the RPM range that you may believe it's occurring all across the power band.

This happens in lots of instances, something can make more power for 500 RPM, but kill it everywhere else... A stopwatch works wonders for this. Even better than the dyno.

[Chris Hamilton]

Thanks Jake. Some real numbers will be nice. I've only compared my supertrapp to stock exhaust and it's certainly an improvement in performance there.

That doesn't take much at all... BUT it actually may be a loss of performance, its just boosting the torque at a very low RPM and it feels faster for enough of the RPM range that you may believe it's occurring all across the power band.

This happens in lots of instances, something can make more power for 500 RPM, but kill it everywhere else... A stopwatch works wonders for this. Even better than the dyno.

He primarily autocrosses his car and blasts around on the street, so torque is certainly a benefit.

One thing I love about the supertrapp system is you can prove what you're thinking pretty easily with 6 screws. More plates, less plates, no endcap, you can do any of that in 5 minutes.

[turnaround89]

Say i actually am able to make my own exhaust system, who makes a good muffler. I don't want the thing to be loud, but i do want to be able to hear the engine. Right now the sound is perfect, could i just reuse the muffler thats on the car and make my headers go into that muffler? How do i go about picking the right muffler for my exhaust setup? What brand would you guys suggest to buy from?

[CliffBraun]

Say i actually am able to make my own exhaust system, who makes a good muffler. I don't want the thing to be loud, but i do want to be able to hear the engine. Right now the sound is perfect, could i just reuse the muffler thats on the car and make my headers go into that muffler? How do i go about picking the right muffler for my exhaust setup? What brand would you guys suggest to buy from?

I like my supertrapp, they're relatively cheap and you can tune them to whatever amount of backpressure you want.

[turnaround89]

Is a super trapp the same thing found on most tuners aka the fart can? I don't want that on my car, maybe i looked at the wrong thing.

[CliffBraun]

Is a super trapp the same thing found on most tuners aka the fart can? I don't want that on my car, maybe i looked at the wrong thing.

Dunno what you looked at but this is what's on my car. Doesn't sound bad (of course I can't hear anything over my intake) and allows lots of room for tuning. I don't believe it's a significantly different sound than most things you're gonna get and they're not really flashy looking.

[Chris Hamilton]

Is a super trapp the same thing found on most tuners aka the fart can? I don't want that on my car, maybe i looked at the wrong thing.

No, not a fart can. I have seen very few hondas other than my own with supertrapp mufflers, and it is very quiet.

[r_towle]

I had a first generation Foley type header on a race car.
Once you get the header down to a single flange, you can bolt on any muffler you want.

I had two setups and finally settled on one.
The first was a $25.00 cherry bomb from thrush, this bolted on to a three bolt flange.
the second was a hush thrush (again $25.00) muffler but it was an oval muffler similar to all the modern ones for V8 type cars running dual exhaust.

With one muffler it was perfect for the car, had a great tone, was cheap, and had very little back pressure so the car could scream at the higer rpm range.

The key was decibal levels for my choice...I need to stay under 95ish of they will pull out the sound meter.

Rich

[turnaround89]

I like the sound of the supertrapp, 1.) does the different ID for the tube affect the supertrapp at all or 2.) is that just for different exhaust setups, some with larger tubes other with smaller tubes? I figured it was the second one, but might as well ask.

I think i might buy a super trapp and work on getting the headers from the 4-1 setup.