I have been putting off doing headers for a while because of the hassle involved with a getting a new Y-Pipe made. What I am wanting to do is put a set of Flowtech longtubes on my '94 F250 4x4 with the 351 and C6. I want to keep the cat and the 3" exhaust I have behind the cat.

My question is this: does anyone have an idea how much it would cost to have an exhaust shop fabricate a Y-pipe that would go from my Flowtech longtubes' 2.5" collectors, back to the cat, while keeping my O2 sensor, cat, and stock exit location?

The whole reason that I have not got headers yet is that I do not have a ton of money to throw at this and have no idea how much it will cost to have a y-pipe made to fit my application.

 

It probably depends on what state you live in and how high the cost of living is. Here on Long Island where rent and utilities are sky high, we would probably charge between $225 and $275, that's without seeing what's involved.

 

I was gonna guess between $250 and $300. But It might be cheaper than that. I once had a complete exhaust system built for $600 including the muffler and new y-pipe and O2 sensors and a cat.

 

You are going to install longtube headers, and run them into a single exhaust? Correct? jd

 

Building a Y for long tubes should be really easy and cheap. There are ready-made Y pieces where all you do is extend the ends to meet the collectors and add the mating flange to connect to the headers. Parts could be bought on Ebay for less than $70.

If its not under $200 shop around.

 

Thanks for the advice everyone, $200 is about what I was guessing. And yes, I do plan on running longtubes into a single exhaust system. As far as low end power goes, longtubes and single exhaust will be just as good as duals, and I do not want duals anyway.

 

The combining of headers into a single pipe will negate some or all of the gain (if any) you may have obtained from the installation of the headers. jd

 

I disagree. The y-pipe if built properly can add additional exhaust scavenging. Dual exhausts can negate this effect. The phenomenon I am referring to here can be observed in headers. You can get the triple y or the common collector type. The collector types have more potential, but can be peaky and unstable at lower rpms, the triple y tends to enhance the entire powerband more evenly. The y-pipe helps stabilize and equalize the exhaust flow and that helps improve low end power, without being restrictive at the higher rpm ranges.

I'm going to agree with "1994 F250: 351, C6", I think he has the right idea. Besides, its his truck, he knows what he wants.

 

Thanks for the support Bear River. There are a lot of people out there that think duals are the only way to go and this is nonsense. Using headers with a single exhaust system is, if anything, superior to duals when used on a truck where low-end torque for towing and hauling is prefered over high-end horsepower. I am not aiming to insult jimdandy, but saying that running headers into a single pipe will negate the gain from installing headers is FALSE. If headers and single exhausts did not work when combined, companies like Banks would not produce exhaust systems that utilize headers and single exhausts. In addition I would say that you could look to plenty of people on this site that have used headers in combination with single exhausts and would be able to tell you they experienced a gain in power.

 

Well, and regardless, almost any header is less restrictive than a stock manifold. In any case, we are all entitled to our own opinions, but from my perspective, duals have little or no advantages when used on stock motors unless you view the added cost and weight as an advantage.

 

Cost and weight not withstanding, you can make the same power regardless of whether you use 1 or 2 pipes. Its all in the design.

 

Good point Ken....

 

Headers on a stock engine sometimes produce little results unless the system was restrictive to begin with.

From what I have experienced, dual systems produce better torque under about 4500 rpm if properly designed. Torque is what is desired for a heavy vehicle that carries heavier loads. By combining the headers into a single larger pipe, it slows the scavenging effect of the system. This occurs because the larger pipe radiates more heat cooling the exhaust. Cool exhaust is heavier, and does not flow well, and when the hot gasses coming from the headers encounter the heavier gas it slows the velocity of the gasses.

Another problem is signal reflection, and other phenomena, but I won't get into that. As stated, it's your vehicle and money, do what you want. But, for others reading the thread, it might be something to give some thought to.

Banks, like other mfgrs., is there to sell product. Using what they do as a guide might be misleading. Using that argument, Ford could save money by using one exhaust on their higher performing engines, but I see most have duals, as do other mfgrs. jd

 

A larger pipe radiates more heat than 2 pipes? Can you prove that a single larger pipe looses more heat than duals. It has much less surface area to loose it through.

Most of Ford's high performance engines on vehicles newer than '95 are single exhausts. You can't tell unless you get them in the air because many have dual outlet mufflers or y into two pipes before the mufflers. I have a complete catalog of the converters systems for Mustangs, Thunderbirds, and other performance cars built by Ford, and none of them built after '95 are true dual systems. This is also true of several other manufacturers, including BMW, Mercedes, GM (they do have some true duals and they are dogs). Yes, some of these companies built so true duals, but those applications are producing large amounts of power and can justify true duals because they are top end cars and money is not an object. Their engines are also optimized for racing. And one more thing, none of them are trucks (with the exception of the dog GMs, which dual into the muffler so they are still not true duals).

Are are probably right that you can produce more power with a proper design, but is it worth the added expense and weight? Probably if money is no object.

If you look at the differences in how a header is built versus factory manifolds, I think you would agree that any header will flow better than a stock manifold and produce more power. If should produce a very noticeable improvement in power as many people on this forum can attest.

 

Blah blah blah....

Flow is FLOW. It doesnt matter if its through 1, 2 or 9 pipes. Low end gains can be just as good on either setup, IF DONE RIGHT. Look at some factory Y pipes and then wonder why headers have little to no effect. And whats the point of headers if its all going into too small of a pipe anyways? jimdandy has some valid points.

I really dont understand why you are so single minded about exhaust systems. And using factory designs as a basis for your argument is laughable. If the designs were so good, noone would be getting the kinds of gains they are by opening up their factory exhaust.

Factory single exhaust systems are more often than not made the way they are FOR COST REASONS. Its cheaper to use a log manifold and small diameter pipe since most of the buying sheep... I mean public dont care anyway.