U20 Headers

[Andrew Griffith]

I'm looking to buy a U20 header that fit the example of the pics I included. Unfortunately the owner of the pic will not sell. Maybe a possible lead to who might have info. Andrew

[Daryl Smith]

If that is a U20 head, then that is a custom header...probably a one-off....and I'm having a hard time figuring how it fits in a roadster.

[Andrew Griffith]

Daryl it is a racing header and yes it's a U20 head. It was designed back in the 60tys but was used for quite some time..but just racing. It comes out under the frame and one tube over the frame to exit on the left side under the body and then dumped right in front of the left rear tire .

[Andrew Griffith]

I'll have to get with you about the megasquite fuel injection and your thoughts on it..thanks Andrew

[theunz]

Here’s a link about some headers made in Australia which are highly regarded. These are quite expensive especially when you add in the shipping. Keep in mind that the best headers in the world won’t make much difference unless the whole engine is designed around them. Another thing to consider is where they make their power. Giving up low and mid range just to have screaming power at 6,000 plus rpm’s is not going to be fun on a street driven car.
viewtopic.php?t=31823

[spl310]

That looks similar to the BRE header. They are tough to find

[Andrew Griffith]

Yes it is BRE style header. I can have one made but its pricey. It's been dynoed and on that engine it was worth 14hp. I'm building a pretty radical stroker u20 and this style header is going to be for a higher rpm range then 6000. It's also exits out of the car frame and 1 tube over the top of the frame to end exiting at the left rear tire..also adding to the vintage direction for the build. I will probably have to have it fabricated. Andrew

[Daryl Smith]

Andrew,
IF you are going to go to the trouble of having a header built, I would suggest you read the info in the header thread here:
viewtopic.php?t=2083&hilit=new+modified+header
Some frivolous banter in the first few pages, but, some good info overall, and some links which help explain details...
Breaking it down, my opinion....
-a 4-2-1 design for under 8,000 rpm. Helps with packaging/fit and weight.
-3 step design for max torque and horsepower.
-Buy the "Pipe Max" header design program and play with it to see how things change with horsepower and rpm (primary size is more dependent on horsepower than displacement) Pay attention to info in sections about port sizes.
- Check "Burns Stainless", HyTech Exhausts (anti-reversion chambers), Calvin Elston blog/website?..
- Once you have the design nailed down, you should be able to find a reputable shop to build it for you nearby....
- 'Equal length' is less important than a design that flows well, too many bends slows flow.
- 'Tuned length' relates to peak horsepower rpm - higher rpm/shorter header, lower rpm/longer header. The headers we are typically using are a bit short for the typical use, it shows in the Ozzy built header noted above...

While I agree that for maximum power it must be designed for your specific engine (which would require testing on a dyno - with changes), a well designed and built header should show significant increases in torque and power through the rpm range - power under the whole curve is more important than peak power.
Prepare to spend....
Calvin Elston is a top notch builder, and he's only 1/2 hr drive away (Elston Exhaust Inc - Mathews, NC)....If he can't help you, perhaps he can point you to someone reputable who can.

[Andrew Griffith]

All great info..I will do my do diligence..as the engine is going to be pretty involved. Over 8000rpm for road racing and will be a stroker. But very much agreed every engine is different depending on the build. Thank you very helpful. Andrew

[Mike Unger]

All great info..I will do my do diligence..as the engine is going to be pretty involved. Over 8000rpm for road racing and will be a stroker. But very much agreed every engine is different depending on the build. Thank you very helpful. Andrew

Andrew,

If you plan on vintage racing there are certain things that are not allowed so I would build the car to the rule set so you have plenty of places to race. If you have any questions let me know.

Mike

[Daryl Smith]

With a U20 stroker at over 8000 rpm you must be searching for 250 to 300 hp? n/a?
While that header looks to have a reasonable design, I think you can do a lot better with some modern input. Don't waste your time guessing. Put the engine specs through a decent dyno program to get a good idea where it will land, then start work on the header.
Size of primaries and overall length of the header makes a difference, as does the collector size and length. Don't be set on where the exhaust ends, as that could change with collector length. Do look into the use of a 'choke', 'taper', and 'anti-reversion' .
https://burnsstainless.com/blogs/articl ... collectors
https://www.hytechexhaust.com/products.html (anti-reversion chambers [small bulge in primary] in most headers)

EFI? For a highly tuned engine it's by far the best way to go. With efi and a crank-fired ignition you have complete control at all rpm. Wider powerband and better milage, no comparison (exactly what you need for road racing!). I got into Megasquirt because it was affordable and relatively simple at the time, their systems have become quite sophisticated and capable since then, although they still have the comparatively simple MSII based systems. I started with the MS1, which is extremely basic, but, was still a big step up from carburators. Sourced almost all of my efi/ignition components from the junkyard, cheap! Won't ever go back....
DIY Autotune is not far from you in Gainsville, GA. I'm sure they would be happy to talk to you about your needs and come up with a kit you'd be happy with.
There are many other capable systems on the market, I am just not familiar with them....

[Andrew Griffith]

Thanks Daryl

[Alvin]

Try contacting Les Cannaday at Classic Datsun Motorsports in SoCal, he might have one or know where to locate.



There are also several examples of custom made BRE-style headers here on 311s, from user "gtrbg":

[tangoterje]

Wow… let’s hope those engine mount insulators are in good shape!

[Andrew Griffith]

Thanks for all the information..I do appreciate it and from knowledgeable people familiar with these cars..Andrew