Do ya love yer sidepipes??? - Page 2

rblong · #1 (**permalink**) 11-27-2006, 09:56 PM

""Even without ends It'll still neck down to the 3" OD inner pipe. Why would you do that anyway? The custom inserts/Cobrapacks are identical internally and there's no new ceramic job either. Am I missing something??""

Dave - I thought you said that they recommended using the longest Cobrapack you could? What I was thinking is that without the "ends" you could get another 6 inches of Cobrapack muffler. We do not need the ends to weld to since they will fit in our housing. Am I making sence, or have I lost it

Bruce

496fe · #2 (**permalink**) 11-27-2006, 10:10 PM

I've often wondered about the collector design. There has never been a collector design like the Cobra sidepipes. I know the road racers spend a lot of design time on collectors and many-pipes-into-one designs. So do the drag boys.

Brian

Rick Parker · #3 (**permalink**) 11-27-2006, 10:31 PM

I want to give a "High 5" to Rare Iron for the following comment, he hit the nail on the head

Quote:

There's no sense spending THOUSANDS of dollars on a high HP motor only to have your mufflers rob you of 100+ HP (not to mention torque) in the power band.

This speaks volume along with what Duane said about pipe sizing and muffler design. The problem herein lies in the fact that many of you have increased the cubic inch displacement of your engines substantially, some by over 100 Cu In. yet you are still attempting to force it through a header and muffler sizing that was intended for a 427, and was not all that great on it. You must remember that header design an theory was only about 3 year old when these cars (427's) were on the road. If you look at the original collector design and if you understand exhaust theory somewhat you will realize there is severe turbulance in that design and there is no band aid that will make that design any better. Enter the "Merge Collector", read on some sites how effectively they are and how they assist in extraction of the exhaust gasses and you will soon see that it is not just the muffler that holds the key to what you are looking for.

undy · #4 (**permalink**) 11-28-2006, 04:46 AM

I agree whole heartedly with the idea about not wasting money on a high $$/HP engine if you can't make the horse power materialize at the tires. That's why on the intial dyno I did a before 'n after with the side pipes (and the air filter too..no difference there). Merge collectors/equal length primaries/stepped primaries etc, etc are all important too. Once I get the back pressure right via a better flowing muffler design and regain 80 of the 100 HP I can then spend some more $$ on Merge collectors, trying to get another (maybe) 15 horse power. The vast mojority of our power losses are due to restrictions aft of the collectors, IMHO..

undy · #5 (**permalink**) 11-28-2006, 09:26 AM

Quote:

Originally Posted by rblong

""Even without ends It'll still neck down to the 3" OD inner pipe. Why would you do that anyway? The custom inserts/Cobrapacks are identical internally and there's no new ceramic job either. Am I missing something??""

Dave - I thought you said that they recommended using the longest Cobrapack you could? What I was thinking is that without the "ends" you could get another 6 inches of Cobrapack muffler. We do not need the ends to weld to since they will fit in our housing. Am I making sence, or have I lost it

Bruce

Bruce, I was going with the longest sidepipe insert muffler that would fit inside my 4" sidepipes. They are going to put a conical "bell" reducer/increaser on each end to generate a semi-press fit inside my side pipe. They have a picture of it on their web site. He said the flow would be the same as the Cobrapacks.

Dave

rblong · #6 (**permalink**) 12-03-2006, 09:02 PM

Dave - get you pipes ordered? When they gonna come in?

Bruce

undy · #7 (**permalink**) 12-04-2006, 02:48 AM

Hey Bruce!

Yep, got 'em ordered. They're all made and shipping out today. Eric (Chambered Exhaust) left me a V/M Saturday letting me know that they're done and will be shipped out Monday. He's excited that I'll be dynoing shortly afterwards and posting the results for everyone to see. I'll let you know the SOTP results as soon as I drive it.

different note... I'm about 2/3 way through the new fuel system install, what a PITA. I'm having to relocate everything to make everything fit. I'm now running a new 140 gph pump (Holley Black, good for 750 hp), an oil filter style/size filter filter/water separator, Holley "Big Port" fuel pressure regulator and all piped 8AN.. It'll be completed this week..

Back to the dyno when it's all done!

Dave

rblong · #8 (**permalink**) 12-13-2006, 12:56 PM

Dave - I have the stage II KC heads and upgraded fuel system. Nice to hear you picked up some HP. Did you do a motor dyno? I was curious what you got at FW so I could compare to mine for effeciency and pipe loss once on chassis dyno.

I really hope to get to do a with siprals and without at the dyno shop soon!

Bruce

Rick Parker · #9 (**permalink**) 12-13-2006, 01:46 PM

When I made my sidepipes and headers for my 289 I initially planned on using the spiral type Lobacks with a 1 inch tube in the center of the spiral baffles, all inside a 3" tube. I found the sound to be real raspy, but even more, the tube became blued from heat buildup for about 4 inches in the area of the 1st baffle. This led me to believe there was quite a bit of backpressure and restriction caused by this design and I opted to change to another type.

496fe · #10 (**permalink**) 12-13-2006, 02:34 PM

Rick,

You are right about the sound of the Lobacks. I originally had the long Lobacks with the large diameter tubes (I think they were about 2" I.D.). I couldn't stand the sound! I cut them off within minutes and installed 3" I.D. glass packs with the louvers facing back. Sounds much better.

Brian

G.R. · #11 (**permalink**) 12-16-2006, 11:35 PM

I have a set of Cobra Packs 28" that I have not yet installed. I have a mild built 289 hi-po K code, bored 025 over running a mild cam.

What is the advantage of reverseing the muffler with the louvers facing rearward?

496fe · #12 (**permalink**) 12-16-2006, 11:48 PM

The backwards-facing louvers are less restrictive, but louder.

bremillard · #13 (**permalink**) 12-27-2006, 09:14 AM

I've got a 540 Chevy motor that engine dynoed at over 700 h.p. When I installed it in my car using Shell Valley supplied sidepipes the motor would barely run. I cut open the sidepipes and removed everything. I welded in some 3 1/2" CarChemestry baffles and welded the sidepipes back together. This mod allows the motor to breathe but it is much noisier. There really is no free lunch with mufflers. It will either flow real well and be noisy or not flow as well and be quieter. Each person has to weigh what is right for them. I opted for maximizing power in my application. -Bob

decooney · #14 (**permalink**) 12-27-2006, 11:14 AM

Quote:

Originally Posted by bremillard

I've got a 540 Chevy motor that engine dynoed at over 700 h.p. When I installed it in my car using Shell Valley supplied sidepipes the motor would barely run. I cut open the sidepipes and removed everything. I welded in some 3 1/2" CarChemestry baffles and welded the sidepipes back together. This mod allows the motor to breathe but it is much noisier. There really is no free lunch with mufflers. It will either flow real well and be noisy or not flow as well and be quieter. Each person has to weigh what is right for them. I opted for maximizing power in my application. -Bob

__________________________________________________ ___________

Bob,
There are some hi-flow (straight-through, non louvered, non-baffle type) sidepipe muffler designs that are quieter than others at lower rpms purely based on entry/exit chamber design, length, etc. My previous factory pipes were much louder at lower rpms, and 30% less freeflow as compared to my current ones; so it in fact was not a give-take situation for me.

Which mufflers/cores did you choose from Car Chemistry, I see mostly baffle design inserts on their website?

bremillard · #15 (**permalink**) 12-27-2006, 11:43 AM

"Which mufflers/cores did you choose from Car Chemistry, I see mostly baffle design inserts on their website?"

I used the 3 disc weld-in baffles. -Bob
__________________

rblong · #16 (**permalink**) 12-28-2006, 08:42 PM

Mine were open on one end and a 3/4 nch hole in the other - that may be why I got 430 RWHP out of mine.

undy · #17 (**permalink**) 12-29-2006, 04:05 AM

Quote:

Originally Posted by rblong

Mine were open on one end and a 3/4 nch hole in the other - that may be why I got 430 RWHP out of mine.

Hey Bruce,

Yea, a 3/4" hole will flow quite a bit more than my 1/2". I'll probably remove the cap entirely and dyno again just to see. My initial blurb might have given the spiral turbos an undeserved bumb wrap. I'd feel bad if they lost sales due to a skewed report from me.

Dave

BTW... check the new toy in my sig.

rblong · #18 (**permalink**) 12-29-2006, 06:00 AM

Look at you! I mentioned I just bought a new 06 Viper last time we talked and next thing you got a new Vette - well I won't hold that against you since you still got your Cobra

I already have a list of "upgrades" I wanna do to the Vip - I can't keep nothin stock

Congrats!!!