New/Modified Header Design?

[dbrick]

My thought onthe x member was if you needed to cut it, cut off the bottom part, and up and over, inverted U shape to the size needed. I was then going to weld on a thick plate with a smile shaped drop to tie it back together. You could concievebly make quite a large hole as long as you plate it.

The header design sounds great, how much would it cost to build another?

[wvitPR]

Hi Dave,
The cost?, well, I am not sure, as this was not high on my priority list but I would have to say probably about 500-700 USD at a guess, it is like everything, once all the development work has been done they are probably easy to reproduce, But they took a couple of attempts to get them to fit. I do however have a JIG just in case I needed to replicate.
Phil

[albert gast]

after watching sam neave build a lot of headers , a few observations . don't forget these are racecars.
short tubes into a merge collector .
equal length is best , but too many bends to get equal length is bad .
after the merge on a four cyl. reduce pipe dia. to two inches , then a two and one half tail pipe .
different length tail pipes may produce better results . mine is 56 inches with a turn down at the end . not doable on a street car .
like phil said cost would be $600 to $700 dollars for the work involved .
al gast

[Daryl Smith]

As Al says that is for a race car (200+ hp if I remember correctly), and people have to remember that each part of the exhaust will be different for each car depending on how it is prepared. Cam, compression, displacement, horsepower output all have effects on exhaust needs to get maximum power out.

For most of us who aren't racing there is no need to get that specific. There are general principles, lengths, diameters of pipes, and designs (4-1 or 4-2-1) which will work well for a broad range of street engines.

Even when doing the math and trying to conform to the principles it is sometimes impossible to build a system to comply.
My car for instance, should have a 1 7/8" exhaust, by my calculations (guessing 120 to 130 hp). However, there is no 1 7/8" flex pipe available. Compromise was to go to 2". I will probably lose some low/mid torque because of this, but as with everything automotive, compromise is the name of the game!

Phil,
Is yours on a U20 race car as well? Do you mind sharing your primary/secondary sizing? 1 3/8"? 1 1/2"? 1 5/8"?

[albert gast]

daryl ; have 1 5/8 pipe now , thought to go larger but frame clearence and getting the clamping washers to work would be a challenge . when my son and i built the car we had an old rallye header ,and it worked quite well . wonder if someone still makes this header . they fit good and have a nice flange at the end to bolt up the head pipe .
regards ; al gast

[Daryl Smith]

Sorry, not letting this thread die yet.......

Anyone buildiing an exhaust system for their car should read this thread:
http://www.gofastnews.com/board/engine- ... esign.html" onclick="window.open(this.href);return false;

Lots of good info there, as well as some good links for further reading.......

[Daryl Smith]

This website has a good program ($40. US) for anyone who may be interested in improving their exhaust 'system'. It will calculate the proper sizes/lengths for your header and exhaust system.

http://www.maxracesoftware.com/pipemax36xp2.htm" onclick="window.open(this.href);return false;

It 'mostly' confirms, with a few variations, what has been outlined previously in this thread with regards to header primary sizes. With some other calculations and information which are very interesting..........and very useful for modifying an engine.

[dieter ka24de]

Hi Daryl why don't you use the guy that Ross uses. I have seen there work very impresive workmanship for an SR20det. He is the guy in langley that builds headers for VWs,he seems to know how to make a supperior header. I had to have my megan header redone to fit steering and X-mber.The cost and hassle in hind site would have been better to have it custom made in Langley.

[Daryl Smith]

I have someone lined up to build the header. Just have to confirm some dimensions which seem to be different between my drawing and Mike's head. Then get some flanges cut, then off to the header shop.

Ross has been nice enough to allow me to use a rolling chassis with the engine to drop off with them to build the header. Will make it a lot easier than trying to work with the body there.

Does the company that makes the SR20DE-T (and KA24DE-T) manifolds do custom work? I understood they only have them for a few modern engines, and probably made offshore. The SR and KA manifolds they do have are very well priced at around $200 last time I saw....... .

[dieter ka24de]

I was under the impression from Ross that they are Volkswagon specialty header place.They made that exhaust from scratch.So I don't think year is important. My Ka header was completely rebuilt. Must shops that have a milling machine or CNC machine can build it.
Not sure if I know of any $200 dollar custom built parts in this day and age maybe 20 years ago.

[Daryl Smith]

"Not sure if I know of any $200 dollar custom built parts in this day and age......"

IF we are talking about the SR20DE-T manifold for the blue 510, it wasn't custom built.
Ross has never mentioned any shop that he uses, and from what I understand he has NEVER had a header built! But, I'll ask him!
There is a local company that specialises in KA and SR performance. I see them at every autocross I've been at with a maxxed out black 240SX with a turbo KA24DE. Their turbo manifolds are off the shelf at an unbelievably low price. Not more than a couple of years ago it was $200. And yes it was good workmanship. PRD maybe? (Not the diesel shop!)

I have a shop which has quoted the flange to be cut by laser. Just a few details to work out.

The shop I have lined up for the header does quality work, guaranteed for life against cracking, ceramic coated. And built to my design parameters!

I've talked to a couple of so called header experts, first thing they ask is " why don't you use a larger primary pipe?"...!!! If they are experts I shouldn't have to tell them it's a little engine and only needs little pipes!! If they had asked about displacement, usage, cam duration, VE, RPM limit, etc....FIRST, then I might believe they knew what they were talking about.....

How's the car running Dieter? Have you found a place that is secure to put it?

[dieter ka24de]

Amazing as it seems but the Grant removable steering seems to deter the lowlifes so far knock on would. The car is a litttle cold running around at the moment have to use a toque and ski goggles to go for coffee.

Ross told me it was custom built by his volkswagon people for under $400.Ask him.

[dieter ka24de]

The shop you are thinking of that specializes in KA24de and SR20det is PDM racing they did the programing on my chip.They are also connected with Specialty engineering.My engine is tuned to the same specs as the black and pinl 240sx.

[Daryl Smith]

PDM!! You're right! And right on the top of their webpage:
http://www.pdm-racing.com/products/exhaust.html" onclick="window.open(this.href);return false;
Is an SR20DET exhaust manifold on sale for .....$200.00 !!!! (and it's in stock!!)
I still stand by everything I've said. Check your facts. Talk to Mike who owns the car......

I have settled on a 4-2-1 design for my header with 1 3/8" - 1 1/2" - 1 3/4" sizing, going up to 2" for the rest of the exhaust. Tho may also modify one of the vendor headers to a 1 1/2" -1 5/8" - 1 7/8" as well just for a comparison.......

Interesting, in this PipeMax program, how the primary size drops when you go to a 4-1 style header. For a stock 1600, at 85% volumetric efficiency, with a 6000 rpm peak hp it recomends a 1.221" primary pipe! (It gets smaller with higher VE.)
According to the info I have that means the 1 1/2" header available from the vendors is about 50% larger in area than it needs to be! That is costing you power, torque, and milage......

[SLOroadster]

Daryl,
Do you own this program? If so would you be interested in plugging the numbers for my engine in to see what it says? I have flow bench results for the head.

Will