Windsor headers

Pantera International Motorsports

the business that supports this bulletin board

http://www.pim.net/hpage.html

scroll down the page to "headers"

Thanks George.

Do 180's make more power?

quote:

Do 180's make more power?

I researched 180's and came to the conclusion based solely on cost, hassle factor (i.e. working on the car once they are installed) vs. power gains they weren't really worth it, unless I could find a set at a real good price.

As I see it;

Advantages: 1. Different sound; GREAT above 3000 rpm, but below, sounds like an old VeeDub (VW). 2. Shear ‘awh’ factor on opening the deck lid

Disadvantages: 1. High cost; 2. Kiss your trunk goodbye; 3. Need a heat shield or kiss the paint on your deck lid goodbye; 4. Additional weight and the comparatively huge moment arm (leverage) i.e. need support brackets on the transaxle. 5. You have to cut the car up to route the pipes out the back, unless you run them through the opening occupied by the A/C system--meaning you either have no A/C or have to spend even more $$$ to put the A/C up front or in front of the rear wheel.

I also remember reading a shoot out between various headers (on a Pantera) at some point and the 180's didn't show any real significant HP gain over a good set of aftermarket or Tri-Y headers.

The main problem (restriction) with most of the 90 degree aftermarket headers is that they have tiny collectors. I heard of someone who was on a dyno and actually cut off the 2" collectors on their Hall headers and picked up 30 HP right away.

Beware “All 180’s are not 180's”. I have seen some that are simply two independent headers, which is not the idea, there is science behind the 180 concept and reasons for the crossovers vis; (Credit to S&S Headers for the following scientific stuff, they explain much better than I could and it saves me a load of typing!)

In the case of V-8 firing order, the five pulses fire alternately back and forth from left to right collector, giving the ideal 180 degree firing cycle. Then it fires two in succession into the left collector, then two in succession into the right collector. If the proper collector outlet diameter is being used (two sizes larger than primaries) the two pulses in succession load up the collector with more air than it can flow. This results in a very strong midrange torque, but causes the engine to "sign off" early, not reaching its potential peek R.P.M. The improper firing order on a V-8 engine results in the need to use large diameter collectors so the engine will perform well at high R.P.M.s. Unfortunately the large diameter collectors cause a tremendous drop in air velocity, resulting in less scavenging through the entire R.P.M. range.
Often cams are used with extended valve timing to help the exhaust cycling. This results in valve timing overlap (Intake and Exhaust valves both open at T.D.C.) which causes a "Reversion" cycle in the exhaust. When this happens, exhaust actually backs up into the cylinder causing intake air to be pushed back out the intake. This reversion causes "Standoff" (fuel blowing out of the Intake) at low R.P.M.s. This whole improper cycling has resulted in a number of "Cure Alls" to help stop this reversion and standoff.

The optimum cure to this whole problem is to correct the exhaust firing cycle. The two cylinders that fire in succession into each collector have to be separated. This can be done partially by a "Tri-Y" header, where the four primary tubes from each bank merge into two secondary tubes (separating the two pulses firing in succession) and finally collect into a single collector. This type of header helps, but the two pulses are still coming back together at the collector.

The second optimum cure is to cross the two center tubes from each bank, across the engine running them into the collector on the opposite side. This makes the firing cycle in each collector 180 degrees apart, the same as a four cylinder engine. Once this firing order is achieved, the small collector outlet diameter can be used and the "High Velocity Scavenging" at low R.P.M.s cures the reversion problems and eliminates the need for extreme cam duration.

Having equal length tubes and arranging them to fire rotationally adds to the scavenging capabilities. The exhaust gas exiting one tube, passing across the opening of the tube directly beside it, creates more suction on that tube than it would on a tube on the opposite side of the collector.

Going by the science it sounds like they should be good for more HP, but a lot will depend on your motor and application i.e. where's your weak link or restriction? But they sure make a car look like it's going fast standing still!

Julian

Anyone know what the reason for designing the Hall headers with such a small collector? Seems stupid to merge sizable pipes into such a small collector

quote:

Originally posted by 4NFORD:
Anyone know what the reason for designing the Hall headers with such a small collector? Seems stupid to merge sizable pipes into such a small collector

Simply so they would be a direct bolt-in and mate with the oem tail pipes. I strongly disagree with this thinking. The exhaust needs a 3" to 3 1/2" collector, of reasonable length, not the stubby little collector found on most Pantera headers.

Your friend on the DTBB

Pat Mical at Future Auto makes an amazing set of Windsor headers.


Ron

Great advice Ron, I knew Pat made Cleveland headers, didn't know about the Windsor headers. I agree, Pat Mical's headers should be investigated by anyone in the market for headers.

your friend on the DTBB

I ahd a set of his headers on my Yates head engine.They were absolutely perfect! They could not have fit any better!
His Windsor headers are just as nice.
Ron
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Do you have a number for Pat Mical?

(978) 649-2211

I have Pats headers, 3" collector, very nice, perfect fit, hot coated.