Datsun Roadster Forum-311s.org

Linda,
The two headers I posted pictures of work, but are not quite where I would like. Next time I'm feeling rich and find someone skilled and reliable who can build me a header, I have one more design I'd like to try using input from PipeMax and Speedtalk threads and posts from Calvin Elston.

Mike,
From what I have read, the size of the pipe is almost totally related to the horsepower output, although the 'tightness' of the bends can effect the flow, tight bends may require an increase in diameter.

Greg,
Have yet to build my 3rd and FINAL header. May not happen. So far, just the two posted in this thread.

Alvin,
I agree with JT on that one, 1 5/8" and larger primaries just too big for 99% of the cars here, racing or 2.3L stroker maybe...
As always, I'd like to know the actual pipe OD's and the outlet diameter??

The whole point of this thread was to get 4-2-1 headers built to suit the engines we use, not mammoth sized racing headers. Smaller primaries are needed for any gains with the 1600 engine.
EDIT: Keep posting those anyway Alvin, it's always good to see what is being done with headers for these engines, even if it doesn't 'appear' to be progressive.....

JT,
I agree with most of your assessment. I thnk the Sharp manual has a picture of a 4-2-1 header that stated it was good for 9 hp, I believe on a U20?
Fact is, almost all of the 4-2-1 header comparisons I've seen show larger gains in the mid rpm range in both power and torque. I believe this was Lou's assessment also? So, even tho single digit total gains, there should be gains almost throughout the rpm range, and better throttle response.
Would mean a re-tune on the on the carburator also....

Cheers,

Not technically header related (but could be on custom header), 'anti-reversion chambers' look to be an interesting developement for the exhaust system. Little known, but, apparently have been around for many years....

Google Search:
https://www.google.com/search?client=fi ... n+chambers

More info from SpeedTalk:
https://www.speed-talk.com/forum/viewto ... =1&t=57507

Food for thought.....

Very interesting. Smallest in/out diameter tube is 3", my exhaust is 2.25. Looks like the inside of the muffler has a step to stop the wave... could something be made to reproduce that effect and then welded into the exhaust, or is it patented etc?

Hytech seems to have removed their website

Daryl,
Where would you put this in the exhaust system?

Could this be made as the collector also?

Ron,
I am going to put it in just after the exhaust passes thru the first section of the frame.
I did wonder about putting it close to the last 2-1 collector on my header....honestly...I just don't know.... I will ask John tomorrow when I call.

Daryl Smith wrote: ↑Thu Feb 25, 2021 10:48 pm Ron,
I am going to put it in just after the exhaust passes thru the first section of the frame.
I did wonder about putting it close to the last 2-1 collector on my header....honestly...I just don't know.... I will ask John tomorrow when I call.

This is what I was thinking too. That price is very reasonable. I had originally thought you were getting something (2 of them, not 2") that would fit into your primaries, thus my previous question. I'm pretty sure the first pipe in mine is 2.25" but it's been a while... that may be after the muffler. This certainly sounds interesting and so far I have not seen anyone claiming it's bunk (and it's patented). More torque is always Welcome! Thanks as always for presenting this idea to the forum, let's see what's what!