crush/press bent will work fine.

If it tells you anything about pressbent exhaust systems Buschur sells a 2.5 pressbent exhaust. Im pretty sure he wouldnt sell them if they werent worth something. If you arent concerned with getting extremely high amounts of horsepower and are on a budget then I would go for it.
https://secure.buschurracing.com/catalog/product_info.php?cPath=23_56&products_id=205

Sweet. I'll probably go for it then. Just curious, at about what WHP level would I want to upgrade to a seriously nice exhaust?

That's a fantastic price. Bigger is generally better at any hp level (quicker spool, more TQ) but at that price I would do it.

You can get an exhaust at that price on ebay...seriously name brand exhausts are just what they are...name brand.
You can get a mandrel bent 3'' stainless steel catback for LESS than Buschur. They've been proven to work fine. The bolts rust but get some from ssstuds.com and you're golden...
Don't spend what you dont need to...

Is there anywhere that specifically shows the difference in performance between Mandrel and Pressbent?

The thing is a poorly made pressbent exhaust can flow like shit. If its done well with small radius bends it will work perfectly

Yeah, as long as the pressbent piping isnt too jacked up, I wouldn't worry about it. I have 3" pressbent and I'm happy with it. As for dyno numbers I couldn't tell you.

IslandTSI said:

The thing is a poorly made pressbent exhaust can flow like shit. If its done well with small radius bends it will work perfectly

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Thats what I was thinking. We've got a good pressbend exhast fabricator here, as I had one done for my grand am, and was very impressed with their work.

Eastwood, how does your pressbend look where the pipe goes over your rear axle?

Mine is pressbent and i love it. Got my Whole cat-back Exhaust for under 200.00! I still need to get a down pipe. Hopefully soon.

Hey I have the opportunity to get a full 3" mandrel bent turbo back for $100.00 or maybe a little less. Here is the tricky part. Its off a 1992 awd. I have read on here people say that you cant use an awd on a fwd. I have my own welder and have fabed up a few exhausts so I am not affraid to have to moddify this one. It will run under the rear axel like I am sure most 3" do. Should I get it or make one from scratch?

Get it and re sell it $$$$

On a 45 degree or more bend a press bent pipe will lose about 20% of the inside diameter. As long as the bends arent severe, I highly doubt you will know the difference.

Pressbent is fine for moderate hp goals , and with a quality system its worth the ever so slight hp loss.My 3" press system has been on for about three years and is properly designed with slight bends vs harsh bends.Flows enough for my goals (288whp last weekend) and I have less then 400 total (180 for a 3"mandrell Dp/50 for the muffler/50 for the 3" cat and $100 for the piping&welding work)

DSMcamaro said:

crush/press bent will work fine.

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I must strongly disagree with you. There is a huge difference between press bent piping and mandel bent piping, and you shouldn't just write-off the difference between mandrel piping and press bent piping. It depends on what you mean by "fine."

talon95newb said:

Sweet. I'll probably go for it then. Just curious, at about what WHP level would I want to upgrade to a seriously nice exhaust?

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Oh boy ...

Xeiros said:

Is there anywhere that specifically shows the difference in performance between Mandrel and Pressbent?

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Any kind of piping tends to "collapse" when the direction piping is changed. That is to say, if the exhaust piping isn't COMPLETELY straight, then the piping will want to collapse at any slight change.

As you probably know, the mandel piping technique uses an internal support specifically for not allowing a change in the inside diameter (ID) of the piping. However, with the press bent technique, there is no internal support, and thus the ID of the piping can be reduced (and in most cases, is).

Anytime an ID is reduced, you may as well have the rest of the piping system be at the same size as the collapsed section.

For example, if you have a 3" down pipe, a 2.5" test pipe, and a 3" cat-back exhaust system, you might as well have a 2.5" cat-back system. Why? Because the test pipe in this instance is creating such a restriction (aka neck down) that it negates the rest of the system completely. Such restrictions in the piping also create turbulence, as opposed to the smooth flow of the exhaust gases. Every time a liquid (aka air) has to change direction or is forced into a smaller diameter, there is a loss of power.

IslandTSI said:

The thing is a poorly made pressbent exhaust can flow like shit. If its done well with small radius bends it will work perfectly

Click to expand...

The primary concern (at least for me) is the flow characteristics of the piping. Again, even a "well made" press bent exhaust system has the potential of necking down. Thus, immediately after the section of the piping that is reduced, the rest of the piping is negated.

TSIAWDTalon said:

On a 45 degree or more bend a press bent pipe will lose about 20% of the inside diameter. As long as the bends arent severe, I highly doubt you will know the difference.

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I am not completely sure about the percentage you claim (although, you may in fact be quite accurate), but someone "knowing" the difference and the fact of there being a difference is what is being argued here.

lookinfor400hp said:

Pressbent is fine for moderate hp goals , and with a quality system its worth the ever so slight hp loss.My 3" press system has been on for about three years and is properly designed with slight bends vs harsh bends.

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Again, it depends on what your definition of "moderate."

IslandTSI said:

Get it and re sell it $$$$

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Yea I guess I could just turn around and make a decent profit off of it. What the hey ill pick it up.

shaunman1979 said:

Yea I guess I could just turn around and make a decent profit off of it. What the hey ill pick it up.

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The only possible way you're going to make a profit off of a press bent exhaust system is if you sell it to some idiot who doesn't know what he's buying (and thus, what he should be buying).

For example, if you have a 3" down pipe, a 2.5" test pipe, and a 3" cat-back exhaust system, you might as well have a 2.5" cat-back system. Why? Because the test pipe in this instance is creating such a restriction (aka neck down) that it negates the rest of the system completely.


True to an extent. Exhaust pulses much like electricity follows the path of least resistance. Just having a neck down does not negate the whole system, but will make a slight difference.





I am not completely sure about the percentage you claim (although, you may in fact be quite accurate), but someone "knowing" the difference and the fact of there being a difference is what is being argued here.


Came from the shop manual here. Oh by the way, I work at a tint/accessory/performance shop and we do our own exhaust work. Maybe I should have said I highly doubt you will be able to feel the difference, not know. With the goals he has stated, I say buy the system, and put the money saved toward something else.

DSMunknown said:

The only possible way you're going to make a profit off of a press bent exhaust system is if you sell it to some idiot who doesn't know what he's buying (and thus, what he should be buying).

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No I will make a profit if I dont decide to use it becuse it is a SS Mandrel bent 3" from the turbo back. And the guy I am buying it from is the one who dosent know what he has. Seeing as how I just picked up a big 16g, radiator, autometer boost and oil pressure gauge in a pillar pod, K&N filter and a spare 1g mas for $160.00 from him.

personally, i like using DOM tubing, becuase i use alot of chop-saw type turns in custom work and making them out of a pressbent tube wont work right or turn out as good.

TSIAWDTalon said:

True to an extent. Exhaust pulses much like electricity follows the path of least resistance. Just having a neck down does not negate the whole system, but will make a slight difference.

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See, this is what I believe to be true as well. I'm not going to pretend to be an expert on the subject, but by having a neck down alone shouldn't hamper the performance enough to make it as though it were the same diameter pipe all the way back.

Yes, it does bottleneck where it necks down out, but it also opens back up too. An example would be a 3" pipe that necks down to 2.5" around a bend, and then opens back up to 3" after the bend. The exhaust gases would hit this bottleneck at the 2.5" portion, but would open back up when it expanded to 3" allowing it flow more freely again. That in effect, should make it at least better than a 2.5" all the way back.

TSIAWDTalon said:

True to an extent. Exhaust pulses much like electricity follows the path of least resistance. Just having a neck down does not negate the whole system, but will make a slight difference.

Click to expand...

I did not say that a neck down (or multiple neck downs) negate the whole system. I said it will negate the rest of the system.

Again, I must emphatically disagree with you. There will be a significant difference with an exhaust system that has a collapsed section.

Perhaps you are considering a "neck down" as technically being any reduction in the ID, which I would agree to. Let's take another example. Say we have a ten foot long pipe that has an OD of 3" and an ID of 2.75". Now let us assume that in the middle of the pipe there is a collapsed section, where the pipe reduces to 2.74999" for about an inch, then reassumes the 2.75" ID that we saw before. That would technically be a neck down. I would continue to argue that although it may not be "significant" to most individuals, it still is a collapsed section of piping, and therefore is still impeding on the flow of the exiting gases.

TSIAWDTalon said:

Maybe I should have said I highly doubt you will be able to feel the difference, not know. With the goals he has stated, I say buy the system, and put the money saved toward something else.

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We begin to get into that area that the newbies fall into, where they tack on an aftermarket intake system and larger exhaust system and claim that they can "feel" how much horsepower and torque they have just gained.

Xeiros said:

See, this is what I believe to be true as well. I'm not going to pretend to be an expert on the subject, but by having a neck down alone shouldn't hamper the performance enough to make it as though it were the same diameter pipe all the way back.

Yes, it does bottleneck where it necks down out, but it also opens back up too. An example would be a 3" pipe that necks down to 2.5" around a bend, and then opens back up to 3" after the bend. The exhaust gases would hit this bottleneck at the 2.5" portion, but would open back up when it expanded to 3" allowing it flow more freely again. That in effect, should make it at least better than a 2.5" all the way back.

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It depends on how severe the neck down is. There is also the fact of direction changes that many exhaust systems must take (this needs to be taken into account along with reduced ID piping). With my original example that you partially reiterated, that is a significant factor of the exhaust system. I'm sorry to say, but you are fundamentally mistaken and ultimately wrong.

There are impedences throughout the whole system though. The exhaust portion coming from the head, and exhaust manifold are not 3", so by your way of logic, we shouldn't bother improving pipe size, when in reality, it improves performance.

I get what your saying, and I agree that the neckdown does impeed performance, but if you open it up on the other side of the impeedence, it does improve performance. Something you could do to keep a large restriction from happening is if you're using 3" piping for your exhaust and have to do pressbent, do 3.5" for your bends, that way your restriction is minimal.

Take a straw and blow through it. Repeat while slightly pinching one section (or use a loose fitting paperclip). Then repeat while while pinching two sections, three...Each added restriction causes increased backpressure to the total flow. This is not scientific but the general principle is there. Draw your own conclusions.