Pros and cons of 2.5" crossover vs 3"
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Pros and cons of different tubing sizes in turbo kits. I have a set of truck manifolds....
I also have the ability to build my own headers...
Motor is less then 360CI and it will be spinning say a GT47-88mm or larger
Lets say truck manifolds, what crossover and why or why not on the other size.
On the custom headers, 1 3/4 primaries or 1 7/8....2.5" collector or 3" collector on either size...
Discuss.
I also have the ability to build my own headers...
Motor is less then 360CI and it will be spinning say a GT47-88mm or larger
Lets say truck manifolds, what crossover and why or why not on the other size.
On the custom headers, 1 3/4 primaries or 1 7/8....2.5" collector or 3" collector on either size...
Discuss.
Last edited by V6 Bird; Dec 30, 2005 at 08:39 AM.
On The Tree
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From: San Antonio
I would stay with a 2.5" crossover. And a 3" collector. with 1 3/4 primarys
Only if you went over 400" would I go to a 3" crossover
Only if you went over 400" would I go to a 3" crossover
Last edited by Spambell; Dec 30, 2005 at 09:02 AM. Reason: Mistake
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Originally Posted by Spambell
I would stay with a 2.5" crossover. And a 3" collector. with 1 3/4 primarys
Only if you went over 400" would I go to a 3" crossover
Only if you went over 400" would I go to a 3" crossover
think he is an expert, but ya, use the 2.5
unless your planning on over 1500rwhp id use the 2.5 it will allow the velocity of the gasses to remain high and dont think it would cause a restriction till past 1500rwhp.
trying to think of people who use a 2.5" up-pipes, the ohio boys with their pt88/98, they have ran some low eights at 180.
unless your planning on over 1500rwhp id use the 2.5 it will allow the velocity of the gasses to remain high and dont think it would cause a restriction till past 1500rwhp.
trying to think of people who use a 2.5" up-pipes, the ohio boys with their pt88/98, they have ran some low eights at 180.
using larger pipe would just create a buffer, (to a point) Taking more time to create pressure creating lag. Im sure theres a way to figure it out mathmatically wise. Bore x stroke, RPM, CFMs, turbo size, I dont know the formula though.
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thats a large turbo for a "less then 360 inch" mill.. unless your going to use it for all out drag racing.. what is the plan with the car? I know Jose did some testing on a 355inch mill that had minimal variance between the 88 and 76mm units and had a large gap in spool time.. may wanna check for his threads if this is to be a street/strip setup.. for all out drag racing spool is not as important if you have a high stall and transbrake once the thing is ryled up.. it will pretty much remain there through the run.
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
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Originally Posted by RyanJ
I guess Mike wants Corky Bell to respond or something. Check turbomustangs.com, many guys use 2.5" well above 1000rw. Should spool faster as well.
I didnt notice who it was until you guys pointed it out..I was looking for a highlighted name i guess..
My bad.
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Originally Posted by lcvette
thats a large turbo for a "less then 360 inch" mill.. unless your going to use it for all out drag racing.. what is the plan with the car? I know Jose did some testing on a 355inch mill that had minimal variance between the 88 and 76mm units and had a large gap in spool time.. may wanna check for his threads if this is to be a street/strip setup.. for all out drag racing spool is not as important if you have a high stall and transbrake once the thing is ryled up.. it will pretty much remain there through the run.
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
Now can i get some feed back like this as if i went with tubular headers and HVMC's...
Would i chose 1 7/8 into a 2.5" or 3" or go with 1 3/4 into 2.5" or 3" collectors..
I just bought this cool new bandsaw and im ready to fab this stuff up.
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Originally Posted by lcvette
thats a large turbo for a "less then 360 inch" mill.. unless your going to use it for all out drag racing.. what is the plan with the car? I know Jose did some testing on a 355inch mill that had minimal variance between the 88 and 76mm units and had a large gap in spool time.. may wanna check for his threads if this is to be a street/strip setup.. for all out drag racing spool is not as important if you have a high stall and transbrake once the thing is ryled up.. it will pretty much remain there through the run.
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
Its a strip car that will see lots of street use...Solid roller. 7500 rpms should be around what ill spin it too. 8 will be redline, i believe.
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Originally Posted by JZ 97 SS 1500
You don't need anything larger then a 2.5-2.75 max.
Jose
Jose
How about custom tubulars though...
Originally Posted by lcvette
thats a large turbo for a "less then 360 inch" mill.. unless your going to use it for all out drag racing.. what is the plan with the car? I know Jose did some testing on a 355inch mill that had minimal variance between the 88 and 76mm units and had a large gap in spool time.. may wanna check for his threads if this is to be a street/strip setup.. for all out drag racing spool is not as important if you have a high stall and transbrake once the thing is ryled up.. it will pretty much remain there through the run.
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
as for 2.5" I am running 2.5" crossover to a 3" up pipe as mentioned before.. you have to keep in mind that the pulses are still phased to the firing order, so even though the crossover or intermediate pipes on a truck style setup will be seeing all the pulses from each bank, they are still only going to see them per combustion event.. the exhaust tuning should be for the displacement of the engine, matched to the primary size which should be matched to the collector/up pipe size.. step up too much and there will be a pressure loss which will equate to a temperature loss which will create a decrease in exhaust energy pulse velocity relying on the next pulse to speed things up again. so decide what the operating range of the engine will be in terms of rpm.. the higher the rpm operating goal, the larger the primaries and up pipe sizing can be to minimize a restriction and still maintain a smooth thermodynamic pulse flow towards the turbine resulting in quicker spool time and the least amount of flow restriction as possible. this will yield the best performance but as with anything it is completely dependent on what you want to use this combination for. 1-5/8" primaries will do perfectly fine for a 350ish CID motor not spinning more then say 6000 rpm.. but increase displacement and rpm goal and 1-3/4" will be beneficial.. going into the mid 400+ CID and high RPM and 1-7/8" would suit the goal better.. there will come a point of diminishing returns where the primary size becomes too big, slowing down the pulse velocity and thus negatively effecting the overall performance of the system.
so step one honestly decide how you will use your car and then go from there. posting your goals here will assist the people your asking how to more accurately return an answer!
Chris
Last edited by sparkwirez06; Jan 1, 2006 at 08:07 PM.
