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[zambon]

I am planning to buy a set of custom made large diameter headers. I have a person in line to do the work, but I want to utilize the minds on the board to create the design as I am sure that the result will be far superior that way. I have read the other thread and I am looking use tubing with at least 39mm id. Similar to the beautiful set built by Jarle, possibly.
I know that the details of the design are sure to be of the utmost importance. Since this is over my head I ask that everybody weigh in. Help design the headers.
I plan to order a small run (3-4 sets) to lower the unit cost, so perhaps a few others will be able to benifit if they turn out well.
What should my primary and secondary tubes measure, diameter and length? I have a stock engine right now, but I plan to open things up in the future with a Megasquirt and eventually a head rebuild.
I plan to use the CSC style (downpipes?) secondary pipes to keep clearance in check. What about up top? Do I use a design similar to Jarle, with the tubes going directly down, or do I make a more complex pretzel like the CSC design.
I would also like this to be able to fit without extreme modifications.

As everybody reading this can tell, I need some education here .
Thanks in advance

[Dennis]

Make your own primaries and downpipes. MD (also active on this forum) once sent me a paper with drawings of the best setup for a 3.0. I'll add it as an attachment, because I've scanned it and made a pdf of it. Check it out and we'll take it from there.

oh, the attachment is too big. Leave me your email adresses and I'll send it to anyone who wants it.

[EDIT]

or download it here: http://www.dennisderooy.com/ARexhaust.pdf

[/EDIT]

[MD]

Zambon,

Mate, this is a HUGE topic but for the sake of a quick overview here are some hints:-

Just like there a different tyres for different applications eg snow, mud, dry, race, street etc there are different exhaust system requirements depending on the application.

Your job is to make some concrete plans about what it is you want out of your car and what sort of car you want it to be ultimately. You see the needs of a racing engine are very different to the needs of a road car and so the specifications must relate to the application. There is no point in saying you want to use a certain ID pipe because you don't say what the application is going to be.

When it comes to enhanced performance in all rev bands, there is no "one exhaust is perfect for all". You have one of those things on your car now !!Essentially you will be tuning the system (and I emphasise system as opposed to headers) to work best in the rev range you want to operate in commensurate with torque needed.

So for now, my recommendation is that you read the stuff that Dennis is /will send to you then after you had digested it, have a serious think about what you want . Quick street, race ,rally, (Heaven forbid) towing and get back to the forum. Once that is settled, you will get a lot of constructive feedback I am sure.

One final thing I would like you to appreciate. You know how an open "G" string on a guitar has a resonant frequency ? Well your exhaust system also has a resonant frequency and whether this will help or hinder depends on its design and purpose.

Cheers,

[zambon]

Thanks for the feedback. I know there is no one size fits all system. However, there is nothing currently available that is any better than the CSC system which is rather expensive.- I have also been led to believe that it is designed for a 2.5 engine.
As far as how I plan to use the car... I guess I plan to do the standard US street/track dual use vehicle. That said, I do not plan to use the car for any commuting, just running back roads for fun and track/autocross when I can. The car will exist solely for type driving.
Also, I dont want a system to optimize the engine I have now. I want to purchase the system for the faster engine I plan to build in the next year or two. I have not decided whether I want to raise compression or go with forced induction, but I have been led to believe that both would benifit from more exhaust flow.
So, I guess I want a race exhaust. Is there any drawback to having a race system?

please send me the pdf. email=jameszambon@yahoo.com

many thanks for the help

[zambon]

Ok, last post I said I want a ¨race¨system...not exactly. I dont want a peaky system.
Dennis-thanks for the file. Just the type of information I need. I only question the fact that the drawing seems to be designed for a stock 3.0. Also, on the other thread, Jim made some statements that lead me to believe that a larger diameter primary would be a good idea, althouth he said nothing regarding primary length. While my 3.0 is currently stock, I do not want to tune the exhaust for my current setup. The wise thing to do would be to wait until my engine is ironed out and tune the exhaust to the engine but my car is in Mexico now and I can have the system made at a more reasonable cost. As soon as I return to the US my cost goes up significantly.
I would like to build the best system I can with the information I have. Perhaps I am doing things backwards, but this is more fun than doing nothing at all.
For the sake of advancing this thread, I propose that my system be designed to run on a 3.0 with Megasquirt and a supercharger. More or less, this is what I would like to be running eventually.
What would the exhaust valve output of this engine be +/-?
thanks for all of the help
James

[zambon]

Finally have a design roughed out. The credit goes to JimK for designing the specifications. Thanks Jim
I will start getting prices for the build. Hopefully I will know somthing this week.
Also thanks to MD and Dennis for the replys. The link is fantastic.

¨Thats gold Jerry-solid gold,¨ -Banya.

[Dennis]

What did you end up with, Zambon? Post! I'm curious on what points it differs from the system MD worked out in the pdf.