2.5" or 3" exhaust?
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stolle
- Posts: 2241
- Joined: Wed Nov 08, 2006 5:47 pm
2.5" or 3" exhaust?
trying to decide what size i should go with, give me some input not going for super high hp but it will be on a turbo charged car...
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rickles8099
- Posts: 3038
- Joined: Mon Oct 30, 2006 7:53 am
2.5" or 3" exhaust?
3 inch. with turbo setup.... bigger less restrictive exhaust is always better. the turbo creates the torque so you dont have to worry about exhaust piping that is too big.stolle;14410 wrote:trying to decide what size i should go with, give me some input not going for super high hp but it will be on a turbo charged car...
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budget_crx
- Posts: 2722
- Joined: Wed Nov 08, 2006 9:49 pm
2.5" or 3" exhaust?
not necesasarily, the bigger the exhaust the less momentum the exhaust will have to exit the car. I have some more info on it at home, ill post it up when i get a chance, but from what i remember 3" single pipe exhaust was only needed if you were making over 500hp. Besides, less restrictive would better be accomplished by having no obstructionsrickles8099;14411 wrote:3 inch. with turbo setup.... bigger less restrictive exhaust is always better. the turbo creates the torque so you dont have to worry about exhaust piping that is too big.
I vote 2.5

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rickles8099
- Posts: 3038
- Joined: Mon Oct 30, 2006 7:53 am
2.5" or 3" exhaust?
less momentum... yes because 3 inch doesnt need the high flow because it has a higher volume. anything that causes the engine having to work harder to push the exhaust gases out the exhaust is considered a restriction. aka pipes that are too small, cats, resonators, bends, crush bends compared to mandrel bends, muffler.budget_crx;14412 wrote:not necesasarily, the bigger the exhaust the less momentum the exhaust will have to exit the car. I have some more info on it at home, ill post it up when i get a chance, but from what i remember 3" single pipe exhaust was only needed if you were making over 500hp. Besides, less restrictive would better be accomplished by having no obstructions
I vote 2.5
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stolle
- Posts: 2241
- Joined: Wed Nov 08, 2006 5:47 pm
2.5" or 3" exhaust?
i agree with rick turbos dont like back pressure, but then jake has has some good points too im not going to be making insane horsepower so i dont think i need to spend the money on 3" exhaust when 2.5" would be sufficient. if someone had a good enough argument to use 3" i would, so keep the comments comin...
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stolle
- Posts: 2241
- Joined: Wed Nov 08, 2006 5:47 pm
2.5" or 3" exhaust?
this true but if the pipe is too large for the power your making the exhaust gases will cool making them more dense thus making the exhaust gases the restriction.rickles8099;14413 wrote:less momentum... yes because 3 inch doesnt need the high flow because it has a higher volume. anything that causes the engine having to work harder to push the exhaust gases out the exhaust is considered a restriction. aka pipes that are too small, cats, resonators, bends, crush bends compared to mandrel bends, muffler.
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rickles8099
- Posts: 3038
- Joined: Mon Oct 30, 2006 7:53 am
2.5" or 3" exhaust?
i would think that an overpopulation of exhaust gases in the exhaust system would be more restrictive than bigger molecules.stolle;14415 wrote:this true but if the pipe is too small for the power your making the exhaust gases will cool making them more dense thus making the exhaust gases the restriction.
whats more restrictive in a hallway.... too many people trying to go one direction or a couple of fat people trying to go one direction?
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budget_crx
- Posts: 2722
- Joined: Wed Nov 08, 2006 9:49 pm
2.5" or 3" exhaust?
rickles8099;14413 wrote:less momentum... yes because 3 inch doesnt need the high flow because it has a higher volume. anything that causes the engine having to work harder to push the exhaust gases out the exhaust is considered a restriction. aka pipes that are too small, cats, resonators, bends, crush bends compared to mandrel bends, muffler.
this is true, but a 98ci engine is not going to produce enough exhaust to need a 3" exhaust, a 2.5 will still not be restrictive as long as it doesn't have a restrictive muffler or cat.
glasspacks ftw

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rickles8099
- Posts: 3038
- Joined: Mon Oct 30, 2006 7:53 am
2.5" or 3" exhaust?
on a turbo car it isnt about the displacement... its about getting the exhaust gases out of the way of the turbo so it can spool faster.budget_crx;14419 wrote:this is true, but a 98ci engine is not going to produce enough exhaust to need a 3" exhaust, a 2.5 will still not be restrictive as long as it doesn't have a restrictive muffler or cat.
I have a article at home explaining why, ill put it up as soon as i can
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budget_crx
- Posts: 2722
- Joined: Wed Nov 08, 2006 9:49 pm
2.5" or 3" exhaust?
rickles8099;14420 wrote:on a turbo car it isnt about the displacement... its about getting the exhaust gases out of the way of the turbo so it can spool faster.
thats why downpipes are usually bigger than the rest of the exhaust, it gets it all out of the way.
edit: displacement does make a difference because displacement, valve sizes, cam profiles, they all effect how much exhaust will be produced

