Header question for all

[Jolane]

Pete,

Did you happen to read that article about the LS7 engine, linked in another post? (I don't know how to link another post here, sorry) There is a picture of the hydro formed exhaust manifolds they are using. It is unique in that the collector is straight, not a square of four pipes. I think this might work well for a SBC hybrid. It would be narrower where it counts, between the engine and frame rails.

What I am not sure of though is the mating part. The article says "From there, exhaust is routed by a smoothly-tapered extension into a "wide-mouth" catalytic converter. The design greatly reduces the engine's backpressure.". I am not sure exactly what this means. It almost seems like the four collect into the mating peice. If this is the case, I could see this working well to go around the oil filter and starter, just a single tapered piece maybe fabricated from two pieces of steel formed around a wooden buck.

Just curious on your thought about this type of header?

Joshua

[pparaska]

Joshua,

 

Yeah I read that article. I'm no header expert. But Ed Henneman does comment that one of the design considerations for a good header is to have the 4 pipes arranged in a square, the pulses advance around the square as they come down the primaries. In other words, on the left of the SBC, with cylinders 1-3-5-7, which show up in the firing order in the order of 1-3-5-7 (or the right side, with the cylinders firing in the order 8-4-6-2) the pipes would be arranged like this:

 

(1)(3)

(7)(5)

 

and

 

(8)(4)

(2)(6)

 

So that the pulses come out of the pipes in a circular order as the engine fires.

 

Or something like the above, maybe rotating the numbers for better equal length distribution:

 

(5)(7)

(3)(1)

 

or

 

(4)(6)

(8)(2)

 

( Had to disable smilies in this post for the above to work!)

 

Supposedly, the pulse from one tube creates a bit of a vacuum in the adjacent tubes, helping pull the exhaust out of the next one in the firing order.

 

I'd think the straight line type of collector would negate that effect as cylinder 7 fires, then 1, the pulse from the #7 pipe wouldn't be able to affect the #1 tube, since it's at the other end of the straight line.

 

Well, that's all theory to me. Who knows if it'd make a difference on a Z with mufflers, etc.

[Jolane]

Pete,

I will admit that I am not up on exhaust manifold design theory. Thanks for taking the time to explain Ed H's theory (maybe it is proven?). I do though understand a bit about CFD, and from that perspective, the square arrangement does make sense. I am having a hard time though with how much of a difference it will make, even on an engine without mufflers. Maybe it is negligible. My gut says that it depends a lot on the port shapes as well. Maybe the D shaped ports help minimize backflow into the cylinder, so the "scavenging" effect is not so effective.

This problem can also be looked at from a mass flow point of view. When the exhaust exits one of the adjacent tubes, the gas has some velocity. This should create a vacuum effect to the tubes around it. Maybe this has an effect also, but I wouldn't think that the tube length is so critical.

Now scavenging, as I understand it, is based on wave theory. Basically, the sound waves travel up and down the pipes, creating pressure waves that help scavenge the exhaust. This supposedly does require more accurate tube lengths, matched lengths, etc. I think though that it also requires a completely matched system. On motorcycles, the length of the silencer and pipe are critical to HP, and can have a measurable effect (according to the pipe manufacturers anyways). This though is the system as a whole. Those pipes are fairly straight-through also without chambers.

In the end, I am confused and would love to know just how much better a well designed header is over a block hugger. I am guessing the advantage is not worth the cost and effort on a street car with mufflers.

Joshua

[pparaska]

Joshua,

 

According to Ed, who has been building and testing headers for racers since at least the early 60s, the following maximizes power from a header design:

 

"Maximizing Performance is accomplished through correct selection of a header’s performance design parameters. These are:

 

Tube Size;

Tube Length;

Collector Size;

Collector Length;

TRUE Equal Length header tube design;

Efficient Collector Shaping;

Efficient Port Matching."

 

He doesn't believe in Tri-Ys, as he's always been able to build a better 4 into 1 than a Tri-Y, even as far as low and midrange go. To him, block huggers are WAY too short and uneven length to work on the street, let alone the race track.

 

If you want some really interesting reading/listening, buy his HEADER DESIGN Infopak with the CD:

http://headersbyed.com/ordrinfo.htm

 

$22 with shipping. It's a pile of articles, a CD with him talking about header design, catalogs for headers and parts, lots of info with theory and testing info. Lots of advice if you want to build your own headers.

 

An October 98 CHP article showed a 40 hp increase from using the equal length long tube HeadersbyEd set over the blockhugger that has a straight arranged collector. (he includes a reprint of the article, as well as a detailed analysis of it's findings, etc. in the infopak). Ed complains that they switched engine parameters on him, so the headers he sent them weren't an optimum design for the engine they tested. He also complains that they didn't retune the carb/distributor for each header (??? morons!). He believes his headers would have shown improvements if that were done and shows his reasons why.

 

I'm not saying Ed is the authority on header design, but he has a few things going for him. He has a mechanical engineering background, he tests his theories, he's been at it for 4 decades, and he's picky about details, so he probably finds the truth better than others who might try header design. JMO.

 

BTW, his brochure (it's on his website too) about how the novice, with the advice service he has on header design, can build a better header than the big manufacturers, as far as performance and fit. Yeah, his kit for building a set for the V8 is about $500. But it's supposedly quality stuff, including hand build custom collectors.

 

I'm "this close" to ordering a kit, to tell you the truth. If I build a set through him, I'm going to see what it'd cost to send them to him and have him build a jig for them. The way he makes his jigs, he can build a set with larger or smaller primaries if that's needed. Seeing as the JTR setup in the Z with the old school SBC is a pretty static geometry as far as fitting headers goes and with me using the hardest-to-fit Canton oil pan and blowproof bellhousing, the headers I would build should fit any JTR/Gen I SBC Z, except for maybe exhaust port height variations. Believe me, I'm seriously thinking about at least building my own, and then seeing how much or if Ed would be interested in building a jig off my headers.

[MikeJTR]

I am semi-interested in producing long-tube headers for the small-block into the Z car, however, from what I have seen, the transmission tunnel in the footwell area would have to be hammered in quite a bit to work with most of the automatic transmissions, and I don't know how people would feel about beating the transmission tunnel wider. Also, running long-tube headers under the starter can cause heat related starter problems. In addition, long-tube headers radiate a lot of heat into the passenger compartment.

 

We recently had short-tube 1-3/4" headers made for the LS1 into the Z car. It took a lot of time, cost a lot of money, and we have only sold a few sets, although, there are only a few LS1 Z cars being built.

 

We recently had long-tube LS1 headers made for the 1993-1995 RX7, and it was quite an expensive lesson. We did this because a number of people were willing to spend $800 for big-tube LS1 headers, and we think the headers may fit other applications. We have sold over ten sets, but we still haven't recovered our costs in this project. This is a link that shows the progress of the RX7 LS1 long-tube headers, complete with dyno runs:

 

http://www.torquecentral.com/showthread.php?t=25045

 

Another link, which shows the headers, and prices is shown here:

 

http://www.jagsthatrun.com/Mazda-RX7-LS1-V8_Order.html

 

The RX7 LS1 1-7/8" long-tube headers did help the lower rpm torque, and high-end horsepower, compared to 1-5/8" Edelbrock shorty headers, but the headers are expensive to produce, expensive to store, and have a very limited market.

If people on this board come up with a custom long-tube header design, I can look at having them produced by Sanderson Headers. which is located near us. The problem is cost, which could go as high as $750/set. The reason I am posting is to find out if people on this board are willing to spend $750 for headers for a small-block into a Z car. And are people willing to beat the transmission tunnel wider? And are people willing to put up with starter problems caused by the heat?

Let me know what you think.

[pparaska]

Mike,

 

Thanks for considering this!

 

BTW, I didn't see the dyno runs in that link to torquecentral. I'd love to see those.

 

As for your questions:

1) "... are willing to spend $750 for headers for a small-block into a Z car"?

 

Yes, I would, IF they had a decent collector on them. The short piece of garbage that some might call a collector that was on the prototype header they first built is a JOKE. The ones they put on the second set didn't look very impressive either.

http://www.torquecentral.com/attachment.php?attachmentid=9275

 

With the length of those collectors, they have room to make them a real merge collector, but didn't bother.

 

I'd problaby want to buy as set without the collectors, and use something decent. I don't understand why a place like Sanderson isn't more up to date with collector designs.

 

They'd also have to be equal length and at least 34" primaries. It looks like it can be done. It might take some doing, but it's been done:

(Take a look at the picture near the bottom of the page and the description)

http://www.cardomain.com/memberpage/645045/1

 

I'm not sure if there is extensive mods to the underbody to make room for that or what.

 

I've got enough room with even my blowproof bellhousing and Tremec in a 240Z to have 2.5" duals. Making the collectors take up the volume of the head pipes is doable. Having room for 4 primary tubes past the back of the engine is the hard part!

 

2) "And are people willing to beat the transmission tunnel wider?"

 

Sure. as long as it doesn't mean the gas pedal doesn't have room anymore!

 

3) "And are people willing to put up with starter problems caused by the heat?"

 

A good heat shield between the headers (should definitely be coated) and the starter will solve this problem. All you need is a double walled shield with an air gap, like the aftermarket ones sold.

http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1634&prmenbr=361

But you need to have the shield go beneath the starter as well. I modified one like above to do that on my existing setup.

[jt1]

originally posted by MikeJTR

 

the transmission tunnel in the footwell area would have to be hammered in quite a bit to work with most of the automatic transmissions,

 

 

long-tube headers radiate a lot of heat into the passenger compartment.

 

Right on both counts. I went from Hooker block huggers to the S&S's, and I just don't see how you would get by the oil pan on an auto without some pretty serious hammering. It's tight with my tko, but it would be a little better if the headers were a better design. The floorboards in my car are noticably hotter now than before. I had never noticed it with the block huggers, but it's obvious now, even with the S&S's ceramic coated inside and out. About 30 min driving and you began to feel the heat on your feet. I haven't had any starter problems yet, but it's plain the starter is exposed to more heat with the long tubes.

 

I didn't dyno the car, but there was a noticable performance improvement with the S&S's, and it was pretty much all the way across the powerband, say from 2K up to 6.5K.

 

I would pay $750 for a properly fitting set of headers if they were quality constructed. But- I don't think there's any way to get that "proper fit" for an auto and straight drive with the same set of headers.

 

John

[Mikelly]

John, Did you have any ground clearance problems at the track last week?

 

Mike JTR, You probably need to POLL the group to see who wants what... We have more people in this thread with manual transmissions that would buy headers than autos, but that doesn't mean they aren't out there. I know JOhn, Pete, Mark I., Jim M., and Myself would be able to spend that kind of money. I know there are a LOT of other members who have mentioned wanting better headers. I just can't speak to their ability to cough up a large nut like $750+ shipping.

 

Tim Hepburn made some tri-Ys that looked like the BEST PROTOTYPE for our application.. They had a long merge and looked an aweful lot like the LGM headers I just installed on my C5 Corvette/ LS1.

 

Heat soak on the headers... I think the shield is one solution. The other that I would recommend doing WITH the shield is to move to a remote starter solenoid and MOVE the solenoid out of the engine bay. Mine will go inside the car, in the area where the factory fuse panel on a 280Z WAS once located. I moved one on a previous V8 Car to the fenderwell behind the tire and did away completely with my heat soak issues, but this car is a track car, so I'll pu a lot of things in the passenger compartment on this project.

 

As to hammering the floor boards, I think anyone who has done your swap isn't affraid of breaking out the hammer to widen the tunnel. Most of us did our own swaps and understand first hand the challenges you faced in pioneering this swap (Although Kim Blough, Mother of all Hybriders ~cough ~Bullshyte~ would have us all bow at his feet).

 

Come up with a prototype, or contact Tim offline to see what he did. I think he had some great ideas and could possibly put you in touch with the guy who bought the headers from him.

 

Bottom line is this application will only suit guys pushing above 400HP and needing better exhaust flow, due to more cubes, or a forced induction application. Most hybridZers will be fine with block huggers... Hell I ran 10.98s in a 383/ T56 combo with 1 5/8th block huggers, so they aren't "that" restricting... But spending the kind of dough most of us have spent, it would be a shame to leave 20HP and 30#ft. of broad and usable torque on the table...

 

Mike

[Jolane]

Thanks Pete for the info on Ed's information pack. I think an order and some reading is called for. I really appreciate all your your feedback on this.

Joshua

[jt1]

Mike, I've never banged the pipes during a track event. Ride height 6" to the flats on the bottom of the rockers, 2" header clearance on the pass side. The damage in the pic I posted occured where a paving crew had stopped for the weekend and left about a 3" drop in the pavement. Car is sprung stiffer than most street driven cars, 250F/275R, so it hasn't been an issue on track. I would NEVER attempt to cross a speed bump with it, that would be a disaster.

 

John

[ZROSSA]

Joshua,

The Headers by Ed info pack is really full of comparisons and Ed's opions but not really any hard facts on how to make headers. I think he wants you to spend more $ on his design service, then you get the real usfull info. The tape/cd is very usfull for putting small children to sleep on long car trips. I have book called " performance tuning in theory and practice" by A. Graham Bell. It has all sorts of formulas for finding the right size header for your aplication. His formulas are all based on exhuast valve opening before bdc. And then the rpm you want to tune the headers to. There is a table in the book so if figure out the opening before bdc I can look it up. When you have this info you can then figure out the size of pipe you need.

ID=Square root cc/(p+3)*25 then *all by 2.1. CC is volume of 1 cylinder

 

Hope that makes sence.

There is a formula to do the tail pipe length and size as well and collecter size as well. If you want them let me know.

 

Might be worth getting the book. Its been recently updated so some of the info may have changed from what I have here.

 

Cheers, Douglas

[Jolane]

Thanks Zrossa! I have been looking for information on header design, it seems that most engine buildups though just choose a full length header and run with it. Obviously, this doesn't work for us.

I will try to find the book you mentioned as well.

Joshua

 

EDIT: WOW, that is an expensive book!

[Psykovertible]

actually no. could you expound on that formula so that idiots (me) can plug numbers in more easilly.?

 

what is "p"

 

what is "cc"

[ZROSSA]

P Is your primary pipe lenght

cc is the volume of one cylinder in cubic centimeters

 

The book may be expensive but I wouldnt do without it.

 

Douglas

[pparaska]

Interesting Header Design web site. Free registration (if you're not a company) to use their design software (online).

 

http://headerdesign.com

 

I found that for my engine, estimated HP, and using a "performance factor" selection of 6, I get the following recommendations:

 

General Engine Specifications

Total Number Of Cylinders in the Engine: 8

Cylinder Bore Diameter 4.155 in.

Stroke Length 3.75 in.

Compression Ratio 10.5:1

Peak Engine Horsepower Measured at the Flywheel 550

Engine RPM at Peak Horsepower 6200

Performance Factor (See Table) 6

Exhaust Port Length in Cylinder Head 2.2 in.

No. of Collected Primary Pipes in One header 4

 

Primary Pipe Inside Diameter 1.71 in. (which is about 1-13/16" OD for 18 gage tubing)

Primary Pipe Length 31.4 in.

Collector Inside Diameter 2.80 in. (which is just shy of 2-15/16" OD for 16 gage tubing)

Collector Length 13.6 in.

Engine Displacement 406.8 cu. in.

 

So for the primaries, it'd seem that 1-3/4" or 1-7/8" would make sense.

For the collector, 2-7/8" or 3" would work.

(Headers by Ed has tubing in 1/8" increments even at 3" range, so 2-7/8" is doable.

 

I reran it for a 500hp engine of the same size, all else equal, and got the following:

 

Primary Pipe Inside Diameter 1.67 in. (which is about 1-3/4" OD for 18 gage tubing)

Primary Pipe Length 31.4 in.

Collector Inside Diameter 2.73 in. (which is just shy of 2-7/8" OD for 16 gage tubing)

Collector Length 13.6 in.

Engine Displacement 406.8 cu. in.

 

Not alot of difference, but it sure seems that 1-3/4 long tubes wiht a 2-7/8" collector

would be fine for what I have planned.

 

Kind of surprising since I was guessing 1-7/8" would be about right, even based on Ed's conservative chart included withe the "Header Talk" CD.

 

Also interesting is that 31-32" primaries is all that's called for.

Those are some long collectors though!

[ZROSSA]

Pete,

Does the program ask for valve timing at all. I had a breif look but didnt see them asking for it. I think its pretty important. All the issiues with exhuasts have me a little confused at the best of times. Dave Vizard doesnt seem to care a lot for custome exhuasts and has some evidence to back it up.( how to build HP vol 1). He is refering to 90 degree crank v8's only though. I tend to believe in Ed, Hytech, Burns and similar designers. I have seen 4 bangers make 15% more power with a good exhuast. Thats one thats designed properly against a custom not so well designed one, Not stock. I think that if you are going to the trouble of making headers they may as well be the best you can make.

I also think that the reason your collecters are so long is that the program is designed to run without an exhuast. The whole length of the collecter wont be converging, a lot of it will be straight tube. Ed calls these collecter extensions. I will post the links of exhuast people that look like they know what they are doing tonight. Got to go to work now.

 

Cheers, Douglas

[pparaska]

I am semi-interested in producing long-tube headers for the small-block into the Z car' date=' however, from what I have seen, the transmission tunnel in the footwell area would have to be hammered in quite a bit to work with most of the automatic transmissions, and I don't know how people would feel about beating the transmission tunnel wider. Also, running long-tube headers under the starter can cause heat related starter problems. In addition, long-tube headers radiate a lot of heat into the passenger compartment.

 

We recently had short-tube 1-3/4" headers made for the LS1 into the Z car. It took a lot of time, cost a lot of money, and we have only sold a few sets, although, there are only a few LS1 Z cars being built.

 

We recently had long-tube LS1 headers made for the 1993-1995 RX7, and it was quite an expensive lesson. We did this because a number of people were willing to spend $800 for big-tube LS1 headers, and we think the headers may fit other applications. We have sold over ten sets, but we still haven't recovered our costs in this project. This is a link that shows the progress of the RX7 LS1 long-tube headers, complete with dyno runs:

 

http://www.torquecentral.com/showthread.php?t=25045

 

Another link, which shows the headers, and prices is shown here:

 

http://www.jagsthatrun.com/Mazda-RX7-LS1-V8_Order.html

 

The RX7 LS1 1-7/8" long-tube headers did help the lower rpm torque, and high-end horsepower, compared to 1-5/8" Edelbrock shorty headers, but the headers are expensive to produce, expensive to store, and have a very limited market.

If people on this board come up with a custom long-tube header design, I can look at having them produced by Sanderson Headers. which is located near us. The problem is cost, which could go as high as $750/set. The reason I am posting is to find out if people on this board are willing to spend $750 for headers for a small-block into a Z car. And are people willing to beat the transmission tunnel wider? And are people willing to put up with starter problems caused by the heat?

Let me know what you think.

 

MikeJTR, have you given this any more thought? We still don't have a solution for long tube headers from what I can tell.

[Mikelly]

Well based on the info you collected Pete, It sounds as if the S&S solutions would be a good fit IF THEY HAD GROUND CLEARANCE!!!!! DAMN!

 

Mike

[Tim240z]

Y'all are a bunch of girls!!

Go to http://www.motors.ebay.com and buy a pair of header flanges. Then go to http://www.summitracing.com and buy some 1 3/4" mandrel bends....and build a set of headers!!

 

[Mikelly]

No!

 

I'm using the piles I bought and had ceramic coated...

 

Besides, what else do I have to bitch about?

Mike:wink: