Why 4-1 header?
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From: Long Island, New York
'05 C230SS 6MT, 1966 Triumph TR4a IRS, Shelby Cobra 427 Supercharged
4 into 1 will give you more power at the top end, but gives a flat spot in torque at low RPMs. 4 into 2 into 1 gives more power mid range. I guess the 4 into 1 might be better in our case, because it keeps the car from dying off before the shift, but I would like to see a more mid range since that is where it is more usefull to me. If I can gain some power around 2k-4k it would make passing easier and all in all, make the car peppier in the range that most of us drive, how often do we hang out around 5500 RPM?
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From: The blue white rock, third out.
2002 C230 Coupe(M111)
Given that you have to rev the M271 so much more than any of the other motors, I think going for the most gain on top is the best bet. Besides, none of you guys look at where the power comes on, just how much you gain.
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From: NY
2016 C63s AMG
Originally Posted by Outland
Given that you have to rev the M271 so much more than any of the other motors, I think going for the most gain on top is the best bet. Besides, none of you guys look at where the power comes on, just how much you gain.
Where do your cars get going? What rpm range?
Last edited by pugguy2001; Dec 29, 2005 at 09:53 PM.
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headers
correct me if i'm wrong but isnt it that dragsters have a 4 to 1 exhaust manifold setup? IMO, wouldn't it be better if all the exhaust ports have direct access to the main exhaust pipe rather than reduced to two more pipes before it becomes just 1 pipe? wouldnt there be a mild restriction in a 4-2-1 setup compared to a 4-1 setup? IMO again, i think an engine breathes rather better with a 4-1 setup rather than with a 4-2-1 setup and delivers more torque at low RPMs specially if coupled with a down pipe exhaust system. my two cents worth..... 
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Originally Posted by coupesleek
correct me if i'm wrong but isnt it that dragsters have a 4 to 1 exhaust manifold setup? IMO, wouldn't it be better if all the exhaust ports have direct access to the main exhaust pipe rather than reduced to two more pipes before it becomes just 1 pipe? wouldnt there be a mild restriction in a 4-2-1 setup compared to a 4-1 setup? IMO again, i think an engine breathes rather better with a 4-1 setup rather than with a 4-2-1 setup and delivers more torque at low RPMs specially if coupled with a down pipe exhaust system. my two cents worth.....
Dragsters live in a different world than street cars, WFO all the time.
Backpressure is not a bad thing, it all depends on how the entire system from intake to exhaust is engineered. There are a lot of complex pressure waves happening throughout the entire rev range and if designed correctly some backpressure creates waves that are reflected back into the engine to help with scavenging the cylinder and help it fill back up. This can be engineered to happen at various points in the rev range and can be used to move the peak torque point around to enhance real-world driveability or full-on racing performance. Often there are trade-offs and so real race engines will sacrifice low-end or mid-range for top-end, but not always.
The key message here is that the entire system needs to be taken into account when you make a change to guaranteee the goals you are seeking are met. Just deciding to pop on a 4-1 header because racers have it may leave you with a major disappointment.
- Eric
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Originally Posted by lokisdog@yahoo.
...Backpressure is not a bad thing, it all depends on how the entire system from intake to exhaust is engineered. There are a lot of complex pressure waves happening throughout the entire rev range and if designed correctly some backpressure creates waves that are reflected back into the engine to help with scavenging the cylinder and help it fill back up. This can be engineered to happen at various points in the rev range and can be used to move the peak torque point around to enhance real-world driveability or full-on racing performance. Often there are trade-offs and so real race engines will sacrifice low-end or mid-range for top-end, but not always.
The key message here is that the entire system needs to be taken into account when you make a change to guaranteee the goals you are seeking are met. Just deciding to pop on a 4-1 header because racers have it may leave you with a major disappointment.
- Eric
The key message here is that the entire system needs to be taken into account when you make a change to guaranteee the goals you are seeking are met. Just deciding to pop on a 4-1 header because racers have it may leave you with a major disappointment.
- Eric
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headers
nice input to this thread..... but is pugguy really thinking of transforming his car into a dragster?.. not really sure about his intentions but one thing for sure is that changing his exhaust manifold from a 4-2-1 setup to a 4-1 setup would not really result to an engine failure would it?... i dont think so....cheers 
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From: NY
2016 C63s AMG
Like coupesleek said we got some nice info on this thread. What do our cars have from the factory is it 4-2-1 header., like coupesleek said. There is a sheild over them so I couldnt see. Any way soon enough I will have the Kleeman header install and I will see the results first hand. As far as doing all theses mods I just like to know that my car has a little more power than the factory ones.
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From: Diamond Bar & Anaheim, CA
2003 C-Class Sportcoupe
Stock cars do not have a tube header system. They have an exhaust manifold. Headers will probably give you about a 15hp gain over the stock exhaust manifold. For the I4 cars, there is one exhaust manifold. For the V6, V8, V10, V12 cars there are 2 manifolds, one on each side. If you want to show off your headers, get stainless steel ones.
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Originally Posted by pshek
Stock cars do not have a tube header system. They have an exhaust manifold. Headers will probably give you about a 15hp gain over the stock exhaust manifold. For the I4 cars, there is one exhaust manifold. For the V6, V8, V10, V12 cars there are 2 manifolds, one on each side. If you want to show off your headers, get stainless steel ones.
Depending on the car and it's initial intent, you might get less than ten horsepower, to almost 30 with headers.. but depending on the car. I think the LS400 with the 1UZFE had custom headers for under a thousand dollars being developed that had around a 20hp gain. However when you look at something like the M5 E60 already...
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From: Diamond Bar & Anaheim, CA
2003 C-Class Sportcoupe
Exhaust manifold M111 I4 engine
See the exhaust manifold (brown color), it's one piece. Pictures came off a "smurfmobile." 2002 C230K M111 engine, inline 4.
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From: Diamond Bar & Anaheim, CA
2003 C-Class Sportcoupe
"Tube" header same car engine
Same car with headers with blue anodized coating or powdercoated. V6-V12 cars usually have more HP gain from aftermarket headers than I4 cars because of the larger motor displacement. For example, it isn't unusual to see a large HP gain on V8 corvettes just from headers. Therefore, I can't really say you will see very much gain on a M111 or M271 engine, but on V8 or higher, you should see a good gain in RWHP.
