Boss 302 Quad Pipes on a GT500

[tasdevl]

Tob,

Thanks for the links - just ordered the Boss 302 book, looks like a fascinating read. Did you ever try your QTP cutouts, or just figured you'd leave the pipes open all the time?

I'm going to get arrested with these sidepipes. Over the past couple of days, side windows down, foot on the gas, and wind it out to redline every single chance I get - the car sounds and feels so much more aggressive with that wraparound sound that it's too addictive :fm::fm:

What I realized today in trying to record the sound again is that my iPhone can't capture low frequencies well, and part of the experience is feeling those lower frequency vibrations through the car as well. I would guess you'd have to drive a Boss without the attenuation plates in place to really experience the same thing. I'm finding the sound reflects off surfaces like walls and curbs beside the car really well with the sidepipes, making it fun to drive past buildings or walls close to the road while dropping back a couple of gears and getting on the gas.

 

[tasdevl]

Interesting to read that the engineers tuned the Boss with that little 5/16" hole in the plates to get exactly 80.0 decibels.

 

[Tob]

Tob,

Thanks for the links - just ordered the Boss 302 book, looks like a fascinating read. Did you ever try your QTP cutouts, or just figured you'd leave the pipes open all the time?

There is quite a bit of insight regarding development and production. It doesn't matter which engine you have in your S197 chassis - the book is a must have.

I felt that even wide open the pipes are subdued. Remember that Briggs and Stratton size muffler wedged inside it...

I'm going to get arrested with these sidepipes. Over the past couple of days, side windows down, foot on the gas, and wind it out to redline every single chance I get - the car sounds and feels so much more aggressive with that wraparound sound that it's too addictive :fm::fm:

I know the feeling. I appreciate the burble they emit under light load such as when you are puttering around town in a 30 mph zone. Heads turn, not because of some top fuel dragster sound shrieking "LOOK AT ME" but rather a tone that says that you've done something that Joan Claybrook wouldn't approve of.


What I realized today in trying to record the sound again is that my iPhone can't capture low frequencies well, and part of the experience is feeling those lower frequency vibrations through the car as well. I would guess you'd have to drive a Boss without the attenuation plates in place to really experience the same thing. I'm finding the sound reflects off surfaces like walls and curbs beside the car really well with the sidepipes, making it fun to drive past buildings or walls close to the road while dropping back a couple of gears and getting on the gas.

I'm convinced that unless you are there in person you'll never capture the real life sound in a recording, digital or not. And yes, sitting at a stoplight, the pipes direct just the right amount of burble towards an adjacent vehicle.

I've never been impressed by the warble that the blown modular motor's emit. Pales in comparison to my E303 cammed fox coupe. But the Boss quad pipes change all that.

Interesting to read that the engineers tuned the Boss with that little 5/16" hole in the plates to get exactly 80.0 decibels.

I agree. They tuned the car to be just under the legal limit. Props to Carney and crew.

 

[shelbysvt]

I still don't get why the hole originally is so tiny. Was it just because of the decibal legal limits?

 

[Tob]

From the link I posted for you up above...

 

[tasdevl]

Yep, if you read the excerpt from the Boss 302 book that Tob posted, engineer Shawn Carney from the Boss development team says:

"the cool thing is that we deliver the car literally right at the legal sound limit", says Carney. "But the system is designed to allow the customer to easily remove the plates. They can then drill out the plates for custom tuning or leave them out entirely. When you remove the plates to open the pipes, like when someone goes to the track, you get the full sound experience. There's also a back pressure reduction for a modest power increase."

I'd be intrigued to know what the sound level is without the plates. I'd also be intrigued to know what the car would sound like with the boss rear exhaust, whether it's a different note or not. Working in a mechanical engineering department while not actually being an engineer, I tend to be intrigued by a lot of things. oke:

 

[shelbysvt]

I see so it indeed was for sound. So this exhaust seems more to be for sound than performance. But the left the option up to the driver to remove the plate completely when going to the track.

So if I were to buy this from buyfordracing it would come with the these plates I'm assuming with the little hole in it?

And probably this would be better kept that way because then I would not experience any drone or stuff like that tasdevl mentioned. This is why according to that article then they didn't make the hole bigger.

Am I understanding all this correctly?

 

[tasdevl]

ahh, sorry for the double post there. Also, long story, but the drone or boominess I was hearing at certain rpms is my ears, not the car. I had hearing issues a while back from a nasty cold that went away, but I've had a cold recently, I noticed when I turned the radio on this morning I got the same effect from louder talk radio voices. It's something my eardrums do with a certain volume when I've been sick, should go away in a week or two. Driving the car this morning I was loving the sound, could not imagine changing it back to stock - it has the aggressive sound the car should have had from factory. And strangely, it didn't bother my 7yr old daughter when she took a ride last night, and she usually complains about everything :cryying::thumbsup:

 

[tasdevl]

shelbysvt,

The mini-muffler in the side pipes takes care of drone (see my explanation above of my issue with my eardrums, and sorry for the confusion), the plate hole sizes just made it louder or quieter. If you leave the standard plate in (the standard plates come with the system), it'll be quieter.

 

[Tob]

I see so it indeed was for sound. So this exhaust seems more to be for sound than performance. But the left the option up to the driver to remove the plate completely when going to the track.

Yes.

So if I were to buy this from buyfordracing it would come with the these plates I'm assuming with the little hole in it?

Yes.

And probably this would be better kept that way because then I would not experience any drone or stuff like that tasdevl mentioned. This is why according to that article then they didn't make the hole bigger.

Am I understanding all this correctly?

The small hole has nothing to do with drone. It was merely to allow a certain balance between the side and the rear all with respect to the entire system being no more than 80 decibals.

:smmon:

 

[shelbysvt]

shelbysvt,

The mini-muffler in the side pipes takes care of drone (see my explanation above of my issue with my eardrums, and sorry for the confusion), the plate hole sizes just made it louder or quieter. If you leave the standard plate in (the standard plates come with the system), it'll be quieter.

I see. I'm reading this article more and I like the whole idea of the 5.1 surround sound for car thing lol.

Though its interesting that they did in fact look into an electronic exhaust but decided not to because it wasn't "mustang" enough for them.

This seems to be like an excellent mod from a sound perspective. Well I'm sold on this idea. When I order it though I'll leave the hole in the plate as is.

 

[AlanSVT]

I hate this thread. I really would like to get this done. But I'm afraid I don't have the skill set for this job. I would have to find someone to do it for me. Plus not so sure how much different I will be since I have the turbos in place of cats.

I really hate my exhaust. It has a stupid drone at 1800 rpms and it pisses me off.

 

[Tob]

Alan, IIRC your system looks exactly like the following photo - correct?

You could use the FRPP kit designed for earlier GT models. Same diameter, tubing is still stainless, etc.

All you would have to do is to make two cuts with either a sawzall or a zip disc wheel, then clamp using factory Ford Torca clamps. If you wanted those two joints welded you could just pay a good muffler shop to do it if you can't. If you could get that part out of the way then just use a sedate muffler out back and you'll be back in business.

 

[tasdevl]

I can vouch for the fact that the cutting and clamping part is very easy, if you've ever used a saw before you can do it. Second guessing yourself over and over on where you're making the cut is a totally different story though :bash::bash::bash:

That turbo setup is crazy awesome.:thumbsup:

 

[tasdevl]

Some flyby videos as promised.

IMG 0410 - YouTube
IMG 0412 - YouTube
IMG 0413 - YouTube
IMG 0414 - YouTube

Going to take the plate with the 7/8" hole out this weekend to see how it sounds, also picked up a plate with a 1/2" hole from a seller on ebay to try out.

 

[Tob]

Alan, Sean, anyone else that was interested in this mod...I just noticed that Ford Racing had posted up an instructional pdf on their M-5220-3VMB kit which was intended to fit '05-'10 GT models. I've been interested in seeing how they were handling the fact that there was no mounting hole for the side pipes at the rocker on earlier models. They followed the same route as I did, except without the welding. This kit should fit 2007-2010 GT500 models as both use 2-1/2" tubing and the tubing centerlines are a match for both.

This system uses a totally custom X/H pipe, unlike that of the regular FRPP Boss kit which makes use of the factory pipe. As such, I have yet to see or hear of anyone adding this kit their S197 - whatever the powertrain. So I can't comment on any difference in tone between the regular Boss kit and this one. My confidence level is high that FRPP configured this one right, however.

I noticed that FRPP's pdf is wrong when it comes to certain production years and whether or not they have the requisite fastener to support the side pipe at the rocker. I highlighted the years and commented in red below

In October of 2011, I contacted one of the people responsible for the side pipe system design on the Boss vehicles and asked him a question related to when Ford started equipping S197 chassis vehicles with the fastener at the rocker...

When did Ford start equipping the S197 chassis with a nut at that juncture? In 2010/2011/2012 models?

Revised convertible v-braces went in in late 2010. That's when the weld nut was added. We made use of it on the sidepipes since it was convenient to where we wanted the pipes to terminate.

Regardless, once the hole is drilled, FRPP supplies a tabbed nut similar to nuts that are used on the control arms (albeit a different size). They are indeed a high quality fastener.

A much more elegant and simpler solution than welding in a nut. This means that the average home installer merely needs a drill/bit, sawzall, and wrenches. Until FRPP releases a specific GT500 kit, this one should work fine for those of you that are interested.

 

[sdonaghey]

I installed the side pipes on my 07 GT that has Kooks LT with catted H-pipe. The sound is really nice. My installers welded in the junction point to the H-pipe, right after the cats (along the bend), so that more sound would travel to the side exits. I then installed QTP cutouts, to control how much sound. Car is nicely loud when the QTP's are open!

 

[bpodner]

Tob,
Your H pipe looks much better than that spider looking thing LOL!

Has anyone spliced an H pipe into a catted X pipe? I have been thinking of getting Dynatech LT and the catted X but want to keep my Boss quads. Looking at the catted X I see that there are clamps after the cats. It looks like the geometry may be the same or close to the H pipes.

 

[1 Alibi 2]

Great thread, thanks for posting..

 

[IA Shelby]

Tob

Thanks as always for looking out for us. Mine is a 2011 so I will either use your template or wait for FRPP to hopefully come out with a GT500 kit.

Thanks

Sean