stupid long or shorter headers?

[WSSix]

In order to build headers that will clear everything on the car and not drag the ground, it appears I'm either going to have to go rather long with the primaries or go short. By long we're talking 40-42 inches and short would be maybe 24-30 inches at best. I know from my reading that the prevailing thoughts are longer primaries are better. I guess the question is are they really worth the effort? I'm leaning towards longer primaries just because I think it would be fun to build and look great. I'd also hope it would help make more power. I have no doubt they will be harder to construct than shorter headers. I don't have enough knowledge or experience to say if it's worth it though. Thoughts?

Thanks

[spode]

42" headers sound way to long. I think most are in the 28" to 34" range. The length is set for max power at a specific RPM based on cam, heads, intake, bore, stroke ect, ect. http://mez.co.uk/mezporting/exhaust_length.html
Make a set as best you can but I wouldn't sweet getting the length exact.
I know it can be just internet chatter but most people consider primary diameter more important then length.
http://ls1tech.com/forums/conversions-hybrids/1623277-custom-long-tube-header-exhaust-build-dyno-results.html
http://www.hotrod.com/how-to/engine/header-basics/
http://www.speedtalk.com/forum/viewtopic.php?f=1&t=26079

[Rick D]

In order to build headers that will clear everything on the car and not drag the ground, it appears I'm either going to have to go rather long with the primaries or go short. By long we're talking 40-42 inches and short would be maybe 24-30 inches at best. I know from my reading that the prevailing thoughts are longer primaries are better. I guess the question is are they really worth the effort? I'm leaning towards longer primaries just because I think it would be fun to build and look great. I'd also hope it would help make more power. I have no doubt they will be harder to construct than shorter headers. I don't have enough knowledge or experience to say if it's worth it though. Thoughts?

Thanks

Trey,

How come you want to build a set of header? I would think for your combination there would be a lot of good choices for headers?

If it's just you want to build them yourself I get that?

As for question, I've worked with a lot of racers that have a lot of different opinions on headers, most alway it comes back to tube diameter is more important or at least looked at more closely then how long. After the tube size is selected then they build them equal length for the room they have in their chassis.

Way smarter guys on here then me on this subject so hopefully they will chime in?

[Vince@Meanstreets]

We tried several headers on an engine dyno and the difference was 8-10 HP but an increase in TQ between Patriot middies and Dyna tech full....that 8-10 HP loss was well worth the ground clearance we gained with the middies.

[WSSix]

Thanks for the replies you guys.

Rick, with all the choices for headers I've seen and am aware of I'm too low for off the shelf designs. As it stands, a typical stacked 4 into 1 collector would hang over an inch below the subframe and that's with the exhaust only 1/2" below the floor. Also, being a WS6 car causes a lot of issues with headers because of two small braces that tie the rearward lower control arm mount to the subframe. I could remove the braces as they are bolt in but they work from what I have read about these cars so I want to keep them. It would be a little easier if I didn't have half height solid bushings.

[carbuff]

Can you find, or build, a set of Tri-Y headers instead? With a 2x1 instead of 2x2 configuration under the floorpan, you should have lots of clearance. That's what I have on TOW, and after a bit of cutting to bring them up a little bit (about 1 inch), they are just about perfectly tucked...

[WSSix]

Bryan, I was originally wanting to do tri-y headers but have been talked out of it due to the sensitivity in getting the lengths correct. From what I've found it is critical and can rob power if done incorrectly. What I had decided on was to do "normal" long tubes with a tri-y merge collector with the collectors all laying flat instead of the first two being perpendicular to the final collector. That way, I only have 1-3/4" pipe to fit under the toe boards. From there, I would just go into 2.5" pipe which only hangs a little below the subframe, maybe 1/2". Tri-y's would definitely solve my issues if I could find someone willing to say what lengths I need with certainty that they would work and not choke the engine.

Cone said flat 4 into 1 collectors are not good. SPD has a 4 into 1 flat merge collector that may work but I still have to have really long primaries to get to where I can use that collector as well.

Basically, on the driver's side the clutch slave cylinder sticks out right where I was wanting to place the collector.

[Ron in SoCal]

Why did Cone say 4-into 1 is not good?

[WSSix]

The flat 4 collector isn't very good compared to a traditional stacked, stacked merge, or tri-y merge collector. The guy at Cone didn't elaborate as to why but I would guess it's a manner of flow velocity. Not sure what the guys at SPD think of their flat 4 merge collector though. I might shoot them an email. I'm still faced with the same problem using a flat 4 collector as a flat 4-2-1 collector arrangement though. If I go shorter on the primary tube lengths, I'll be able to use a stacked 4 into 1 merge collector.

[Flash68]

What's the approx power level here?

[carbuff]

What's the approx power level here?

^ this...

I wouldn't worry about sacrificing 10-20HP in a car if it's going to mean a big headache. It may sound sacrilegious given how much time we spend talking about how to make HP. But when you are driving it, unless you are fighting for that last tenth in some kind of race, you will be a lot happier to have a cleaner/no-clearance-problem solution. Heck, I've been driving my car for a year now without getting it on a dyno to try and tune it for the best HP, and I'm loving having it on the road! (note to self - I need to schedule that dyno session. ;) ).

[WSSix]

Should be a 500hp 383 if I get the supporting mods correct. The company that's doing the heads and suggesting the cam said cars are typically in the 420-440rwhp range with the setup I'm going with. The heads flow just under 200cfm max on the exhaust side. I'm looking to redline at 63-6500. All my math tells me I need 1-3/4" headers. While I'm not trying to build a race car, I don't mind trying to do it as best I can so that I can hopefully surprise people that usually look upon LT1s as junk.

Thanks everyone.

[Flash68]

Yeah I hear ya Trey. I'd go 1-3/4 and the easiest path, which sounds like the shorter ones from your description. Should be a fun and drivable motor with those numbers.

[WSSix]

Thanks Dave. I'm leaning that direction. I figure that so long as I do a good job on them, I should be able to sell them to someone else should I want to try a different design. I believe a big part of making a good header is making it look good and not just function well. So I'll be working on that aspect as well through all of this.

[speedjohnston]

The flat 4 into one collector does not work well on a naturally aspirated car because you lose a lot of the vacuum effect of the exhaust pulse before it. When they are square the pulse before it helps draw the next through, but when they are flat the outside tubes are too far apart. Probably not the best explanation...
You will lose more power with the flat 4 into 1 than if you make long, short or improperly size primaries. If you are supercharged this is less important because you are forcing everything through from the other end.
If it was me, I would consider removing your bracing bars, build the headers the way you want and then see what you need to do to re brace everything. Mind you, I always seem to do what costs too much and takes too long so maybe don't listen to me. Lol

[WSSix]

Those were my thoughts on the flat 4 collector as well.

Redoing the brace may be an option. We'll see. I don't mind coming up with neat little fabrication stuff like that.

Thanks

[tungstenkiller]

The flat 4 into one collector does not work well on a naturally aspirated car because you lose a lot of the vacuum effect of the exhaust pulse before it. When they are square the pulse before it helps draw the next through, but when they are flat the outside tubes are too far apart. Probably not the best explanation...
You will lose more power with the flat 4 into 1 than if you make long, short or improperly size primaries. If you are supercharged this is less important because you are forcing everything through from the other end.
If it was me, I would consider removing your bracing bars, build the headers the way you want and then see what you need to do to re brace everything. Mind you, I always seem to do what costs too much and takes too long so maybe don't listen to me. Lol

Absolutely correct on the flat 4 collector and you don't want to check the price on that collector and if you do make sure you are sitting down.

[WSSix]

Figured I'd bring this back up to the top instead of starting another thread.

I'm building the headers now and have decided to go with a traditional long tube design and am in need of opinions/information. I've got the number one primary laid out at about 32 inches long. I think I'll be able to make the others on that side the same length. If not, they will be within a couple inches. I'm not so sure I'm going to be able to make the passenger side work that well though. I'm not even sure I can get the number 2 to 32". I'm not trying to make equal length headers. I don't want to make a poor design though.

How important is it that the primaries be close to the same length between all cylinders? How much difference in primary length is too much? I'm just a street car with a street engine.

On a positive note, the driver's side header hangs no lower than the oil pan which is about 1 inch higher than the front cross member. They will also be less than 1/2 inch below the front subframe rails when looking at them from the side. The rest of the exhaust system is going to hang that low as well. Ground clearance is going to be good considering how hard it is to run exhaust on these cars. Cutting Hooker long tubes like Woody has done would have been a lot easier, but where's the fun in that?

Thanks