To sidepipe, or not to sidepipe.. That is the question.

pancake

pancake

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Most of the resident guys over here have way more experience with hot rodding than I do so I want to pose the above question.. Is there a noticeable decrease in performance by adding side pipes vs. running an under car exhaust?

Here's my setup:
4 bolt main vortec 383, 10.75:1 compression, GMPP Fast Burn heads with 2.02 1.60 stainless valves, Howards single pattern hydraulic roller .560" lift 112 lsa..

I am running summit steel headers with 1 5/8" primaries, 3" collector.. and the 2.5" Corvette Central exhaust through magnacrap mufflers. My estimates show that I should step up to something with 1 7/8" primaries and 3" tubing...

Or I could be lazy and just order up a set of those chinese side pipes.

Any input?
 
Side Pipes are cool for sure but some states have strict inspections and side pipes won't pass. Anyways it will depend on the muffler inserts regarding performance.
 
But almost none of the available headers have tuned length primaries and merge collectors to effectively do that. I have yet to see someone run a set of propoerly designed headers here..well..maybe I saw 1 set, the custom headers on Howards race car. The off the shelf stuff, theres no set with equal length headears.
 
I am emissions exempt in Texas because the vehicle is more than 25 yrs old so I do not have to worry about that. They definitely look cool, too. The system i have now is too restrictive so I think it would actually be an improvement.. those corvette central kits step dow to 2" out of the mufflers! It is too quiet for me to properly represent my inner hillbilly.
 
pancake said:
I am emissions exempt in Texas because the vehicle is more than 25 yrs old so I do not have to worry about that. They definitely look cool, too. The system i have now is too restrictive so I think it would actually be an improvement.. those corvette central kits step dow to 2" out of the mufflers! It is too quiet for me to properly represent my inner hillbilly.
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I just bought max flows to replace the way-too-quiet reverse flows.... so I totally get this :)

The thought rattling around in my head is to run turbos into sidepipes without the muffler - but then comes the problem you're going to have to decide which is most important.... hookers stay at 4 pipes to the side for clearance. OBX hang down a bunch (even when right against the frame).... and I'm not sure how I'll resolve that... the hard way (the way I always seem to do things) would be to go 4 into 1, turbo, 1 into 4 then out to the side pipes.... I haven't come to a conclusion yet...
 
Sipepipes are more of a personality question than a hp question in my mind. I love my Hookers, but they will burn your legs if your not careful and are more work to clean. I also love how my pipes sound with auger mufflers which isn't much quitter than open headers.

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Fuelie74 said:
Sipepipes are more of a personality question than a hp question in my mind. I love my Hookers, but they will burn your legs if your not careful and are more work to clean. I also love how my pipes sound with auger mufflers which isn't much quitter than open headers.

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I ran mine open, first, then I built some auger style mufflers, then wrapped some auger mufflers.... with the wrapped auger (had I run it on the street), I'm sure I wouldn't have been stopped by a cop who was lights-flashing on his way to an emergency....

But OMG I swear the sidepipes with no muffler was louder than straight, open headers.... I wore hearing protection because it was so loud, you couldn't think.... the open pipes worked like a megaphone
 
Heheh....aside from all the plumbing and muffler problems, just let your gal burn her ankles on the pipe, it MAY happen ONCE.....but not twice......:gurney::ill:
 
mrvette said:
Heheh....aside from all the plumbing and muffler problems, just let your gal burn her ankles on the pipe, it MAY happen ONCE.....but not twice......:gurney::ill:
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before you put the muffler in the sidepipe, wrap it with header wrap - heat will no longer be a problem.
 
So i have come to the conclusion that any true performance header would have to be custom made. With that in mind, it does not make a shit whether I run side pipe or under car exhaust. The only "tech" info I have found has been self perpetuating rules of thumb on forums. I have yet to see anything backed up with dyno results.
 
If I may think out loud for a moment, I would opine that sidepipes are a cosmetic tribute to the racers which ran sidepipes to improve ground clearance.

Street performance was very likely never considered.:evil:
 
I have not seen any direct comparison either, most SB headers have 1 5/8" primaries, Hooker sidepipes are 1 3/4" or even 1 7/8" - could be a little too big for some... I doubt sidepipes perform better than undercar exhaust with long tubes.
I wanted the look and sound when i installed mine, I don't care if I could have 10HP more with a undercar exhaust.....
 
I can tell you that the exhaust velocity in my current system is pretty high. It is definitely pressuring up and pushing out at the flanges. I think a 4" drainpipe with the spiral inserts might just be the ticket.
 
Twin_Turbo said:
But almost none of the available headers have tuned length primaries and merge collectors to effectively do that. I have yet to see someone run a set of propoerly designed headers here..well..maybe I saw 1 set, the custom headers on Howards race car. The off the shelf stuff, theres no set with equal length headears.
Click to expand...

Well, I think on a C3 it is virtually impossible to make them equal length. I have a set of very old ones on mine now. These have a MrGasket stamp on them, apparently they were originally a Appliance header. Pretty decent.

Lately I've heard that a correct volume chamber right behind the header would have it work as an open header. However on our cars I don't see me running something like that.
 
I love the looks of sidepipes but have yet to hear any that sound good. Subjective comment I know, but most of the pipes I've heard in person or on the net sound like hillbilly trucks with no low end rumble or tone to them. Anyone have good video of a sb chevy to change my mind?

I could see them possibly reducing power a little but but nothing significant.
 
I haven't measured them, but I suspect that the Hooker sidepipes are equal length... a long length, but equal length. The nice part about super long, is you get even better draw (scavaging) from the exhaust system.

That said, I also hear the criticism that they aren't tuned; but they're also 1 7/8 primaries - for most 350s that's quite a bit larger than what they need

There's the 4" sewer pipe (love the term).

I do believe you could tune the sidepipes (okay, I know you can tune them) because they're too big.... if you cared enough for the (perhaps) 25 hp that you could gain by tuning them.

So, my totally scientific seat of the pants analysis. I've run my Corvette with an under-car system (decent one), not even Chinese (dangit), long tube, baffle mufflers - and with sidepipes... if any difference exists, sidepipes have more power - even with reversion mufflers.

But hp wasn't the impetus to change, it was saving my plastic spring from melting.

And sidepipes do not net you more ground clearance... :crutches:
 
The pace car spoiler i am going to put on will not help ground clearance, either. Besides, the pipes are very close to the ground now where they cross under the diff.

Sbg- do you have any pics of how you wrapped your pipes to prevent heat transfer to the sewer pipe? I am assuming you just wrapped the collector?
 
Some years ago I got on the phone with the owner of Schoenfeld Headers in Arkansas I think....we got to discussing a set of 151 Chassis headers he made for SBC, happen to fit my car just perfect with the rack steering, and the collectors are higher than the oil pan, and clear the filter/starter just fine.....

they are unequal length headers, I questioned that, and his comment was....'for some reason, cars like unequal length headers, and engines dyno better with equal length headers'......meaning the UNequal length headers give a less peaky torque curve,....makes sense to me....

and he went on to say that putting on any kind of exhaust pipe and especially ANY kind of muffler will totally negate any gain from the headers, in other words, they are a waste of time and money at that point.....

He could have lost a sale with that comment, but in fact for the 150 bux the headers cost me, at that time, they still on the car doing just fine....and my only issue was melting plug ends on #5&6 plugs, screw it, on with a set of Jacobs ceramic caps, melt THAT, bitch....

but that comment that adding ANY muffler and long pipe wipes out any header gain was somewhat surprising to me, but upon thinking about it, I suspect he is correct, but no one wants to admit it.....so a stock set of late 80's headers from GM would work as well, just remove the air pump crap....:tomato:
 
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