I'm starting on my header fabrication for the Vega this week. The empty engine and trans go back in for the fourth time tomorrow night. I got a bunch of parts from Stahl Headers:
http://www.stahlheaders.com/Frame%20Tubing.htm
Click on "Bending Mistakes". It takes you to prices for a box of random bent tubes in 16 and 18 gauge of different sizes. I got a box of 1 3/8" tube for the primaries and a couple collectors with 2 1/2" exits.
I'll post what comes in the box when I get it.
Nix-
I would like to see how the engine & transmission look in your Vega. I am toying with the idea of using one of the many Rover 3.5 V8s and 5-Speeds to install into a Vega. I have found a brown 1977 or 76 Vega coupe for sale for $800.00. I am a Triumph TR8 guy but for some reason the Vega Rover sounds very appealing. One of the TR8s I have worked on has a Rover 5.0 liter with Buick 340 heads had custom headers (4-1) made that flow really well compare to the typical headers (4-2-1) configuration. What are you going to fabricate; 4-2-1 or 4-1?
-Mike
I'm building 4-1 headers. I don't have current enough pix of the engine and transmission with the customized crossmember for the trans. I'll be putting it back in tomorrow and I'll post some pix then.
I think the Rover v8 is the best swap for the Vega. It's light and powerful if built right. GOod stuff.
What ever happened to Ed Henneman..
"Headers by Ed".
His website has been down for some time now.
He was in south Minneapolis nick.
I tried calling a couple times but no answer. I don't know what happened to him. Weird. That was why I ended up going with Stahl.
I periodically try the url to see if it's backup but no luck. Sad.
He is there but hard to get on the phone. I thought about stopping in for parts since he is only about 40 minutes away. Hmm, my wife only works about 5 minutes from his place of business.
-BMC.
Nice! Where is it? Is it still the same address?
What a character. GOod advocate for header performance.
OH man... I f'ed up and bought the wrong diameter tubes! AAHHHH! I meant to get 1 5/8" tubes and ordered 1 3/8". GEEZ! SO that process is about to start over. Damn.
I would think that 1 1/2" primaries would be plenty for a 215/3.5. I am using 1 5/8" on my 400hp Camaro.
Too late. I already changed the order. They were really coool about it. They are sending me a new set with a return label. COOL! Looks like I'll get 400 hp then!!! SWEET! That was easy.
No. I got that number from Des Hammill's book on the Rover V8. He's saying minimum of 1 1/2" for lightly modified 4.0/4.6L Rovers with stock heads. 1 3/4" for full race engines with 7k redlines. I figured 1 5/8" was a good compromise. We'll see.
OK on that topic. I was planning on making my primaries 40" long. Any input here? Thanks Team!
> I would think that 1 1/2" primaries would be plenty for a 215/3.5.
> I am using 1 5/8" on my 400hp Camaro.
The primary diameter should be based upon what the exhaust port flows.
David Vizard wrote a couple of good articles ("Exhaust Science Demystified"
Popular Hot Rodding, May 2005 and "No Loss Exhaust", Drag Race Monthly) in
which he presents simple design equations for header and muffler sizing.
I use his equations as starting points for Dynomation iterative simulations
so I wrote a little routine to calculate the parameters. The equations are
based what the exhaust port flows at your maximum exhaust valve lift:
OID = SQRT (Ex_CFM * 1.27/FD)
CDiam = 1.75 * OID
where:
OID = optimal internal diamter (inches)
Ex_CFM = exhaust port flow (CFM) at 28" H20
FD = flow density (around 80 CFM/square inch @ 28" H20)
CDiam = collector diameter (inches)
I have tested several sets of Buick 215 and 300 aluminum heads on a local
flow bench and ran the exhaust flow numbers through Vizard's equation:
Buick 215 unported 85 CFM (1.3125" exhaust valve)
Primary ID (inches) = 1.16
Collector ID (inches) = 2.03
Buick 300 unported 116 CFM (1.3125" exhaust valve)
Primary ID (inches) = 1.36
Collector ID (inches) = 2.38
Buick 215 home ported 129 CFM (1.48" exhaust valve)
Primary ID (inches) = 1.43
Collector ID (inches) = 2.50
Buick 300 pro ported 153 CFM (1.5" exhaust valve)
Primary ID (inches) = 1.56"
Collector ID (inches) = 2.73
The above CFM numbers are exhaust flow at 0.5" lift and the diameters are
ID's (internal diameters). You have to add your tubing thickness. Vizard's
rules reflect bank separated 4-into-1 headers on 90 degree V8's with dual
plane crankshafts. For most applications, primary lengths should fall
between 24 to 36 inches with shorter lengths favoring higher RPM. Likewise
collector length should fall between 12 and 20 inches (good for up to 8000
RPM). Of the two, the collector length is much more important than the
primary length. On engines like ours, longer collectors are generally
better. To not pose a serious restriction, mufflers should flow 2.2+ CFM
per HP (the point at which there is a 1% difference between mufflers and
open pipes). In my own limited experience, mufflers can have a big effect.
I dyno tested a 475 HP small block Ford V8 street motor (made peak power
at 5500 RPM) that lost 50 HP through the stock mufflers compared to open
headers with an 18" extension. Installing a pair of 3" inlet/outlet
Magnaflow mufflers, it got all but 1 or 2 HP of that back. Interestingly
enough, there was little difference in peak power on that engine between
headers with 1 3/4" and 2" diameter primaries but the smaller primary
headers (which also had longer collectors) made a bit better torque below
3000 RPM.
> No. I got that number from Des Hammill's book on the Rover V8.
> He's saying minimum of 1 1/2" for lightly modified 4.0/4.6L Rovers
> with stock heads. 1 3/4" for full race engines with 7k redlines.
> I figured 1 5/8" was a good compromise.
Are your Buick 300 heads ported? Uisng Vizard's formula, my ported
Buick 300 heads which peak at 153 CFM (1.5" exhaust valve) would need
a primary ID of 1.56" inches. 1 5/8" = 1.625" OD which should be
close when you factor in the tubing wall thickness.
> OK on that topic. I was planning on making my primaries 40" long.
> Any input here?
36" is plenty long for the primaries. Make the collectors longer
and don't go too large on the collector diameter.
Dan Jones
I did get a mild port job done, mostly in the pockets. All the rough parts have been polished out of the exhaust ports but no change to volume. I'm using 16-gauge tubing (about 65ish thou wall thickness) so it looks like I'm at about 1.5". I figure I'm flowing a little less than 153 CFM. How about, for argument's sake, we split the diff and call it 135 CFM. What do you think? I should be pretty close to where I should be I figure.
shortening to 36" should help me a bit. It was putting the collectors WAY back. LOL! Thanks again Dan.
Nick, I ended up with 32" primaries (was aiming for 36) and that has worked out great. Remember that you can extend the tube into the collector a little ways to get even lengths if you need to, that can help a lot. I think you will find that these headers you are building will really make that engine scream. There's more to be gained there than most people realize, especially when compared to the block huggers and shorty headers that are common.
Jim
> so it looks like I'm at about 1.5". I figure I'm flowing a little less
> than 153 CFM. How about, for argument's sake, we split the diff and call
> it 135 CFM. What do you think? I should be pretty close to where I should
> be I figure.
1.5" primary ID should be fine. With 135 CFM exhaust flow at peak cam
lift, you'll want:
Primary ID (inches) = 1.46
Collector ID (inches) = 2.56
Dan Jones
Perfect. That works for me.
I'm pretty excited to start fabricating. I'm certain I'll be hating this by the time I finish. LOL!
I started fabricating the Exhaust. I bought a couple collectors and a box of bending mistakes from Stahl Headers in PA. Absolutely GREAT company to work with. I messed up the original order saying 1 3/8" when I meant 1 5/8" and when the parts came and they were the wrong size they took them back and paid for part of the shipping. It was really a great experience. I hope to frequent their business and recommend them as much as I can. The headers are 1 5/8" primaries and 2 1/2" collectors. Here's a pic of the parts:
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_273_full.jpg)
I started out using "Muscle Car" TV's idea of welding the collectors in place where they should end up. I wanted the primaries to be about 37" long. The collectors ended up right along side the trans in a convenient slot that appears on either side of the trans crossmember mount. The strange thing is it's symmetrical on both sides. It's almost like they planned on the Vega having dual exhaust! Below is a pic of how far down the collectors hang. They are as snug as I could get them comfortably at 1/2" from the floors. Here also is a couple pix of the collector location:
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_275_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_274_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_276_full.jpg)
I was able to get two tubes in last night. There is a lot of time just standing looking at the puzzle and planning the best solution. I have to thread the steering shaft through the headers too. You can see that in these pix. Having the rack steering although causing me to have to put the shaft between cyl 6 and 8 actually gave me more room to make the tube's transitions smoother than if I'd had the stock gear box/steering shaft location.
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_277_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_278_full.jpg)
Get yourself some "smurf" tubing.. .......[The blue flexible electrical conduit ]
drill some small holes in the sides and cut them to equal lengths..
snake em around till you get them looking good then apply some foam to the inside of the pipe through the holes to harden them..
Once you have this.... its easier to weld up and form the hard pipe how you want it.
You can also use lengths of bare welding or brazing rod to get the right bend angle. Kind of an old trick but it works. Generally start at the front and work back since it's easier to add bends than to stretch the tube. Looks like a good start. Would you mind telling how much the box of bends cost?
Jim
I've been using a piece of romex I had laying about. You can actually see it in the picture of all the tubes. I've been laying it over the bends to get a handle on how I can piece them together. So far it's a lot of fun.
The bending mistakes came out to $150. It was $140 for me because my order was over $200 with the collectors. Stahl has been really great to work with on this. Even though I messed up on the order they still sent off a return slip and paid for the shipping back. WOW!
I have stahl headers on my chevelle.. they make a great product...
I emailed Jet-Hot for a quote on their coating process. Has anybody gotten a Jet-Hot coating before? It looks pretty great. They also sent a bunch of stuff in the mail for me to look at. Magazine endorsements and data. It came with a promo DVD too.
Not cheap though. $370 for my headers. What do you guys think? I think it might be worth it. They claim a big reduction in underhood temps. Like 200ยบ less. Hmmm.
I finished the mock up of the headers on the first side. They look cool! I was able go build them so it can be removed. It just fits. Pretty bitchin. I thought the driver side would be more difficult but I forgot I have to clear the starter on the other side and it's really close to the frame rail. So I've got to have all the tubes go over instead of down along the block. That will make it a little more difficult to remove once it's built. I may have to pull the engine to remove it. We'll see.
I'll have pix tonight. It's still fun so far.
Nic..
Get them done locally.. A lot of the area drag racers send there stuff here..
http://www.newimagecoatings.com
give em a call..
There is a guy that ports SRT-4 exhaust parts and puts a ceramic coating on them. He was saying that it made a big difference. I should ask him if he's willing to coat mine too. I do want to be certain the get coated inside as well as outside. I will definitely call New Image! Great find, Tony.
Here's some pix of my headers! Well one of them. I was able to keep them around 1" or so from eachother in length. I'm pretty keyed up about that. The extra space I made by replacing the frontrail support gusset with a different configuration really came in handy. I also had to wind the tubes around where the steering shaft goes. In my case that's right under the engine mount. Anyway here's the pix:
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_280_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_281_full.jpg)
Here's some pix of them installed. Was able to pull it out with the tiniest margin. It worked out well.
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_282_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_284_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_285_full.jpg)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_283_full.jpg)
Nice work!
Nice! How long are your primaries?
You've done some good fitting work there Nick, and at 1" you're probably closer than 95% of the headers made today. Looks like you may have a challenge on a couple of the welds, probably have to take the tube out, weld up the joints and put it back in. I found torch welding to be extremely well suited to building headers, as often I needed little or no filler rod as I went around the joints. Tig would be the same but costlier unless you already have the welder. Some builders like to weld the tube to the open side of the flange and then braze the back side for crack resistance, which is a pretty good practice. Coating the headers is an extremely good idea. Use a first class outfit who can reliably do both inside and out and will stand behind their work and will guarantee it against salt spray. You want it to last and it's worth a little extra.
Jim
I'll second what Tony says. We have had quite a few headers done there and plenty of our powder coating too. Personally, I have only good things to say.
Also, headersbyed- I still have not tried them but believe he is just exceedingly busy. You can find his contact info on this site at the very last paragraph in this article:
http://www.britishv8.org/Articles/MGB-V8-Headers.htm
-BMC.
Look really great Nicolas.
Those are your flanges, Dimitri! Sweet.
So far the primaries are 37" long. I could take an inch or so off based on my updated cam choice. What do you guys think? I guess I'll wait to decide until I get the final specs on the cam.
I was thinking about renting time on a TIG welder but maybe I could use my brother's acetylene/O2 torch. I haven't welded with one of those since I was in high school. I remember really liking the control I got from the slower process. Jim, are you saying weld the port side of the flanges and then braze the primary side? I've never brazed before. Any special advice?
I'm definitely taking the pipes off the flanges to finish them up. Do you think I should worry about warping?
Thanks Team.
Nick, you should alternate your welding and check often to control warping, you'll get the hang of it pretty quickly. Correct on the brazing. No real tips, just practice some and make sure everything is clean. I like bare rod and can flux for more control of the amount of flux and fill but that's just me. It's like soldering, get the base metal hot enough to melt the rod and make sure it wets properly. On your collector length, the advice I've heard was to run up the engine before coating the headers and look for a band of heat discoloration on the collector and that's where you cut it because that's the end of the standing wave. Maybe so, I took it all the way to the glass packs at that size. As far as the primaries, the longer they are the more they shift the powerband down, and that's played off against the diameter which shifts it up as diameter increases. What is your cruising rpm? I'd put that dead in the center and then adjust upwards for redline. If you tighten up on the diameter the length should decrease and vice-versa.
Jim
OK I finally finished mocking up both sides now. It was actually a little tougher on the right side. I had to run the tubes over the starter and that constrained things a little. I also had to turn them to clear the heater box. I ended up putting the rear tube over the third tube near the flange and down the middle to meet up with the first and second tube to run back. This caused it to be a bit longer. Here's a pic showing the end.
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_291_full.jpg?001919-236)
In this picture I've used the same romex wire I've been using for length. You can see that the previously mentioned tube is almost 2" longer. I'm a little bummed about that. Do you guys think this will be a problem? Also now that I have the final specs for the cam do you think I should make the overall length shorter?
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_292_full.jpg?001919-236)
Here's the final pix:
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_287_full.jpg?001919-236)
(http://memimage.cardomain.com/member_images/5/web/2357000-2357999/2357894_288_full.jpg?001919-236)
It looks pretty good Nick. I wouldn't worry too much about that 2". Ed told me one time that about 90% of the headers made had worse mismatches than that so about the only thing getting closer than that buys you would be bragging rights. You've got a fine looking set of headers there.
Jim
> In this picture I've used the same romex wire I've been using for length.
> You can see that the previously mentioned tube is almost 2" longer. I'm a
> little bummed about that. Do you guys think this will be a problem?
Vizard has tested headers for primary length variations and says that while
180 degree headers are sensitive to a few inches of variation bank separated
4-into-1 headers are not very sensitive. Vizard also says that in his
testing average primary lengths between 24 to 36 inches yield similar results
(area under the curve) for bank separated 4-into-1 headers. At 37" inches,
you're a little on the long side. You might want to trim an inch or two.
Collector lengths between 12 and 20 inches should be goood to 8000 RPM.
In testing on small block Ford Windsors (small port and valve like the
Rover/Buick), 9 out of 10 times longer collector length, up to 25 inches,
will translate into increased performance regardless of cam or RPM.
If the choice comes down to lengthening the primary or lengthening the
collector, go with the longer collector. There will typically be a
noticeable burn pattern inside the collector which will indicate the length
the engine wants (once the engine is properly tuned for fuel and spark).
In my own testing, the mufflers were even more important than collector
length. We've lost as much as 50 HP through mufflers. Straight through
designs like the Magnaflow were nearly as good as open pipes.
Dan Jones
What about distance to the x-pipe? Is this part of "Collector" length on a full exhaust system?