sorry if the above looks like i wrote it... i didnt lol.... got it from this page :2thumbs:
some handy info too
All 4AGEs, including the 20 Valve, have identical exhaust ports. The 20 Valve has 4-2 factory tubular extractors, the remainder have 4-2 cast manifolds. The 20 Valve head manifold bolts at the extreme ends are in a slightly different location to the 16 Valve engines, however the 16 Valve manifolds can be made to fit quite easily.
The standard RWD manifold is a wise option, if it will fit in the car, as by all accounts there is little to be gained by replacing it with a set of aftermarket tubular exhaust headers, however there is much to be gained by going to a larger diameter exhaust system from this point back.
The standard RWD system has 28" long secondaries between the manifold and the tail pipe junction. The TRD RWD exhaust system utilises the original cast manifold and then breaks into 42 mm diameter secondaries that are 485mm to the junction, followed by a 330 mm long 50mm diameter pipe to the muffler, a 640 long section containing the muffler, and finally a 520 mm long megaphone expanding out to 57 mm diameter.
Local tubular headers I have seen are 4-1 design and have either 1½ " or 1 5/8" diameter primaries, with a 2" tailpipe. The headers are not very precise - the RWD primary lengths range from 21-28", the FWD from 12-14". I have been told that 2.5" exhaust systems on 4AGEs are very loud, and that 2.25" is a better diameter to go with.
Best I can figure (from a graph I got sent) the ideal is about 28" primaries on 4-1 headers for a 4AGE. The set I am building for my 4AGZE powered Ford 105E Anglia (1964 car) will be 4-2-1, with 14 inch long 1 3/8" primaries, 28 " long 1 7/8" secondaries, and 2.25" tailpipe. This is based on the best I can figure it out, and what I can get to fit. I am building them from preformed mandrel bends, which will be welded together, hence I have a very accurate means of establishing the lengths. The primaries and secondaries should be within a couple of mm in length to each other. I hope to get them built in the next month or so - I have designed them (only took about 40 sketches, drawings and a couple of weeks of measuring and thinking to do!), now I have to make them.
Personally I would not bother with a custom set of headers, especially in what is basically a road car, however the Anglia is too tight for anything off the shelf to fit. Also if you do not have the factory manifolds, an off the shelf set of headers, whilst they may not be ideal, will still work well, and provide a cost effective solution.
dont know if this will help, but cant hurt :2thumbs:
sorry if the above looks like i wrote it... i didnt lol.... got it from this page :2thumbs:
some handy info too
Appreciate all the info guys! Most people are finding between 650-700 equal length 4-1's are about right. Would love to make up 5 sets 10mm difference to each and test them all! :greenbounce: But, probably not the best bang for buck solution if I cant palm off the other 4 sets.
Gilly - Have you used these headers before? Did one perform better than the other? Would really love to see a few pics with some dimensions. Thanks a bunch mate! :2thumbs:
Fozz - Yeah, it has a steering box setup, but to clarify - The steering idler arm pivots on the chassis and connects to a steering linkage.
jinjaninja - Thanks for the info mate. I was contacted yesterday by someone who said 4 into1, 41mm pipes 650mm went well. Significant increase in rwhp. (about15-20hp)
i'll get pics
i have run both on my current engine (4AGC) but different exhausts as well so its not a direct comparison
I Have a freind who played the NA game for a while with a SR20.
If you buy a collector and reversion cone for BURNS Stainless in the U.S. I pretty should they calculate the perfect dimensions to suit your application.
And it will be the closest thing to perfect that you will get. I have seen these headers make MASIVE difference over the best aftermarket extractors you can get.
Some time the only make a small gain in total power but have awsome increas in low and mid range.
I have seen a set that made 9hp more peak but 35hp gain in other areas.
They will tell you almost allways to use a stepped style wear your first pipe off your head is the same diameter as your port and then after 10 or so inches it will step slightly for 8 or so and then step again before reaching your collector.
They usually converge the collector to a very small diameter, I think they went to 2inch on the sr one I saw and then gradually increase the 3.5 inches before sharply decreasing again to the exhaust size. Which is ALLWAYS bigger than any exhaust shop will recomend.
Check out there web site..
They make geart quiality components and now the exchange rate isn't so bad they're not sooo expensive.
[attachment=20365:toda_4_1.jpg]
[attachment=20366:toda_racinglook.jpg]
Do these look good to you? The new Toda version 2 does not have the spring joints. Toda explain their design in brief on their website.
"For ultimate power the 4-1 type exhaust manifold design is the one to use.
The problem is that power is only made from 4,500 rpm in the process removing drivability.
TODA racing have designed a 4-2-1 system which restores drivability 15% more torque with only 1.5% loss of power.
# TODAs 4-1 type used for comparison.(18100-860-000)
"A bench test(Equal length 4-2-1+ Taper) Design.
Taper design is adopted from feedback from both racing and the bench testing.
Race type high flow junction.
Each section of the manifold has optimized pipe lengths, diameters,
and angles as well as high flow junctions.
Made of light weight stainless steel for both durability and looks.
Flange manufactured by high precision machining center. (exhaust port ø38mm)
Standard catalyst can be used."
Those 4-2-1 's look like a really good design.
hot, what of $$ are you looking at for those?
The latest price list I could see (June 2007) listed the extractors at 98,000 yen or $999.00 AUS (converted on an on line currency calculator), you can also order a stainless steel exhaust system that uses the original RWD cast exhaust manifold (as used by some classes of racing in Japan) for 180,000 yen.........
Chris
sweet, might have to put away the pennies for these babies, exactly what I need next for my car... besides tunes lol.'