Here is a vid of my recently purchased RB True Dual Header to custom dual pipes to a single exit Apexi muffler. Let me know what you all think.


http://videos.streetfire.net/video/1...E485B93EF8.htm

 

nice

 

, we gotta meet up sometime, since we're living in the same town. I would have held the camera for you.

The new exhaust sounds mean!

 

Yup - the NA's want to be full dual.

Sounds like a light flywheel too.

Sweet.

 

I've been kinda scared to drive it around like that it is really loud in person. So I have been using a silencer in the tip, but it makes it sound strange, so I think I am gonna get a RB true dual silencer.

Natey: for sure man I live in Lompico, but I cruise into SC a lot.

Sureshot: I don't know about the flywheel when I bought the car the guy said it had a rebuild..... don't know if any extras were added.

 

Why change the true dual aspect into a single at the end?

 

Well for one I really like the single exit look. For two I got it for cheap.

 

sounds like a to me, but im sure its better in person.

 

Probably not. What is wrong with the way a chainsaw sounds?

 

lol, yeah does kinda sound like a chainsaw.

ive never seen a true dual like that where it collects at the muffler. very nice job

 

Trees will prolly run for cover when you drive around

 

Sounds good. Very raspy, though. Not that thats a bad thing...

 

That has one of the best tones/grunt of an NA I have ever heard wow. If you put a decent muffler or set of mufflers on there I am sure it would sound even better!

 

damn that sounds good! Is there anychance that you can get a under car shot of the coustoms?

 

Yeah I think it is way too loud to be street driven so I am thinking about selling it to go with something a little quieter, but I might just get a RB Dual presilencer and see if that works. Here is a pic of the custom dual pipes.

 

I agree with Sideways7, it's not supposed to sound like that, I'm sure you have a leak.

 

WTF? I thought the whole point of having a "TRUE" dual exhaust was to have 2 (thus DUAL) pipes come out into separate mufflers for better breathing and then you combine them into one? WTF is the point then? I just dont get it.
Or is it just to be different? That I can understand. But did you gain any horses?

 

Don't get rid of the system. That's a long primary system. Other 2nd gen owners should only wish they had that type of setup. I've had long primary, short primary, and true duals between 2 different cars and porting styles and the long primary is by far my favorite setup of them all in terms of power. Yours is loud because you have a very small muffler. This is a personal opinion of course but you need to get something decent on there. I'm not a fan of the small 6" round straight through mufflers. They don't muffle well and depending on how you do it, the tone isn't all that great. The smaller the muffler, the raspier it is. Get a larger oval muffler on there but leave the pipes alone. Even a Dynomax superturbo muffler would be a great choice. They are fairly cheap, muffle well, and will easily flow what your engine requires. It doesn't matter if it can't ultimately flow as well as a straight through. You aren't at high enough of a power level for it to matter. After you max out your flow requirements, anything more is worthless and does nothing. The Dynomax is a fiberglass muffler but I've had them for years with no issues. Rob Golden at Pineapple runs them with peripheral ported engines because of their value, muffling ability, and performance. They aren't the prettiest but they work very well. Put a good tip on it and paint the muffler black. You might find it to have a very nice tone, not be loud, and give good power. No need to change the whole setup again if you can get that from only a muffler. The RB presilencer would definitely be a good idea. With that and a different muffler, it would be very nice.

 

Like rotarygod stated, it is a tuned exhaust setup, tuned for exhaust pressure waves ideally, I believe you got the setup from DevilFC? I loved that setup and wish I coulda gotten my hands on it... but now I am Turbo. i would keep it if I was you and try the different muffler as suggested, maybe in combo with the pre-silencer if the muffler dosnt do enough, anyways, sounds good and good luck.

- Chris

 

Rotarygod, Are you saying that treat the dual pipes as long primaries then collected to a single muffler of larger size instead of 2 smaller mufflers? Wouldn't the pipes being this long lose the scavenging pulses way before the muffler? And if so wouldn't 2 smaller pipe be more efficient at quieting the pulses at half the frequency. I might not be looking at it the right way coz I still just dont get it.

 

Thanks for the advice rotarygod. I am taking it to a good local exhaust shop tomorrow and I will see if I can get it quieted down some, I do like the power just not the noise or tone.

 

I thought it sounded fantastic!
And as for being too loud, I got one with a RB header straight back to fart cans kansas law has changed now so as long as you have a baffle of some sort, it's legal.
If you really wanna make it quieter thow.. there's a kid around here with a header back to two flowmaster mufflers. The car might as well have a presilencer and RB mufflers.. it's not very loud at all. It is, in fact, a nice purrrrr.

 

This isn't a dual exhaust. A typical header is an example of a short primary system. It's still a tuned length that benefits from both scavenging and acoustic pipe resonance. A long primary is really nothing more than a really long header. Obviously this will tune differently. A dual is a system that never collects, or from an effective standpoint, collects at infinity as the pulses eventuallly interact somewhere.

There are many things that affect where the powerband will be. Among these are the length of the pipes before they collect, if they do at all, the diameter of the pipes, the collector size, and even the length and diamter of the pipe after the collector. The muffler style also affects tuning. A chambered muffler such as a Flowmaster (don't use one!) will not be "seen" by the engine. Effectively the engine thinks the exhaust ended at the beginning of these types of mufflers. The area increase inside the mufflers gives it this effect. A straight through muffler is like adding a longer pipe to the system. It increases the effective length of the system. Remember we have actual length and effective length. They aren't always the same thing.

There are some generalizations that many people make about the powerband of each system but these are not rules that are set in stone. They can all be altered and in different setups, one type can be made to out do another while redesigning the system can make that result reverse and give the other system the advantage. This is only true to a point though.

When deciding which system is best suited for your particular application, you need to first decide what the car will be primarily used for. Your style of porting will also affect what system works well for you. Typically the smaller the port overlap, the better a non collected system will perform. Again, this always has to be quantified. A true dual system does not scavenge. I don't care what anyone else says or who wants to argue that. They're wrong. End of story. It tunes according to a principle of pipe organ resonance and that's where the benefit comes from. This is using the acoustic soundwaves that bounce back and forth inside the pipe. The goal is to get a low pressure trough of sound energy to arive back at the port at the right time. This only works over a narrow rpm range though. The longer the pipes, the more of these waves there will be in the pipe to have an effect on anything. Each wave helps the other waves in the pipe as well. A collected system, long or short, will also add the scavenging benefit. Scavenging is when the gasses of one pipe combine with another to use their velocity to help pull the gasses of the other pipe along. You can not have that happen if they never collect.

A long primary may or may not tune to a lower peak rpm than a short primary depending on how they were each designed. It will have a wider affect on power though. If you shift at 7000 rpm and your short primary is tuned to 7500 rpm, that's worthless. If your long primary was tuned at 6500 rpm, that's perfect. You might make a couple of horsepower less at peak power but you'll have more average and that makes you faster. At the end of the day which would you rather have, a higher number on paper, or a faster car on the street? What matters more? This is just an example to get a point across. It's usable power that counts. If you have a peripheral port engine that wants to be driven between 7500-9500 rpm, a long exhaust tuned to 6500 rpm isn't going to cut it. You'd want a short system that was designed to tune you at around 8500 rpm so your average was high. A true dual would have to be short to tune up high but then you run into other issues with high overlap and lack of scavenging that I'm not going to get into right now.

As with any setup, there will always be spots where there is a negative impact on power. You can't avoid it on any system. The key is to try to place this at an rpm that you don't care about. A longer pipe will lower and widen the powerband while a short one raises and narrows it. The higher your needed powerband, the shorter it needs to be. A long true dual system adds a nice margin or power over the full useable powerband when used on stock to midly ported engines. The greater the port overlap, the smaller their benefit becomes and once you get up to a peripheral port engine, you'll stop making power right where the engine really wants to take off.

Understand that the stock box exhaust manifold is terrible. It's effective runner length is only about 2" including the engine runners. This tunes it to about 7000 rpm so it still makes decent peak power but doesn't make the average power that a good set of headers make. The outlet is only 2" on it as well. It cracks me up that people worry about getting larger exhaust pipes when they still have a stock exhaust manifold. For good power, use only as large a pipe as you need and no larger. Smaller is better until you max it out.

There is one thing that can be said that does always apply to exhausts. The farther back the pipes collect, the harder it is to muffle it effectively with a true dual being the hardest to quiet down. As the pulses interact, much of their soundwaves can cancel each other out to some extent. The longer they are collected, the greater this is. Another thing that happens is that the farther back the exhaust collects, the lower the sound of the engine. Don't get this confused with the effect that different sized mufflers have on the system. To me a true dual at 8000 rpm sounds like it is actually at 4000 rpm in frequency. This is because we have half of the number of pulses (waves) in each pipe which means the acoustic frequency goes down. Different frequencies have different wavelengths. As you move a collector farther forward for a shorter collection point, you give the collected sound waves more room to interact. Lower frequencies are longer so the longer the primaries the more these get highlighted. As you get the primaries shortened down, more of the high frequencies get highlighted. Changing the length does alot.

That's enough writing. I could write a book on the topic in far mroe detail but there are almready lots of these out there and this was supposed to be a simple response anyways.

 

A Pex'i FTW!
btw you need to ask someone to hold it for you during night so we can see flames.

 

nice!