6 port turbocharged engine
07-28-12, 10:12 PM
#1
6 port turbocharged engine
Hello, I am wondering if there is a performance difference between 4 port irons vs 6 port irons in a turbocharged application.
NOT a difference in rotating assembly.
Simply put, if an oem built, 4 port, 8.5 rotors engine was used with the stock turbo vs an oem built 6 port, 8.5 rotors engine, what would be the performance difference?
Would the 6 port engine make higher top end do to the port area higher up (I'm guessing?).
I've searched and haven't came up with anything besides full NA 6 port turbo vs 4 port turbo engines.
Trying to decide if I should use 6 port irons or 4 port irons when I build my low comp engine for my near future turbo swap into my gxl.
~Kyle
Sent from my iPhone using my finger.
NOT a difference in rotating assembly.
Simply put, if an oem built, 4 port, 8.5 rotors engine was used with the stock turbo vs an oem built 6 port, 8.5 rotors engine, what would be the performance difference?
Would the 6 port engine make higher top end do to the port area higher up (I'm guessing?).
I've searched and haven't came up with anything besides full NA 6 port turbo vs 4 port turbo engines.
Trying to decide if I should use 6 port irons or 4 port irons when I build my low comp engine for my near future turbo swap into my gxl.
~Kyle
Sent from my iPhone using my finger.
07-29-12, 12:03 AM
#2
talking head
ive had both
..motor i pulled out of my daily couple of days ago is 6p end plates.. G middle plate ( t2 ) and 8.4 rotors ( and turbo oil pump )
manifold was modded t2 with mods to the TB secondary delay to make them work as boost secondaries
mods to the TB are necessary to try and recover the lost bottom end below 3000 rpm due to the all aux ports open
( note my setup has low down woes exacerbated by a 3.9 diff.. and an impco LPG carb )
however,, engine is very sweet from 3 K up.. and does have a little bit more top end than the equiv 4 port / mild port with same rotors
( which i have also run about 5 years ago )
however,, with both setups.. was also blessed to have first used a custom log inlet manifold
( using a t2 bottom as a basis )
and the difference between the 6p and the 4p in the top end is much more marked with that type of manifold
-- indicating to me .. that t2 manifolds are restrictive to the peak power up top past 7000 on both engines ( esp. the 6 port )
.. but do help substancially down low on the 4 port engine
my surmise from all this.. the 6p has a later. wider spread of power potential that is cut short by the various methods to make manifolds fit
ie
- s4 6p inlet manifolds may retain the bottom end but may lack diameter to feed the top end and taper off even earlier
,, and brings issues where they wont seal the ACV passage under the primary runners
( if you have used the better t2 primary plate )
and will require a custom turbo relocation
s4/5 turbo inlet manifolds modded to suit on a 6p engine will have a larger bottom end hole ,,up to 3K but hold power to 7- 7.5 K
( when the turbo 4 port motor tends to taper at about 6.5 k )
custom log manifold / single blade TB
.. will lose substancial power under 2k.. will have made it all up by 4K ... and .. at least in my setup.. have a noticable bump in power above 6.5k up to 8500
( where i back off with standard rotors )
note the log manifold is very subjective to design and volume
.... mine is still running somewhere on a 6port resi engine
( also on LPG turbo and with the tall middle plate )
and was a stab in the dark .. but it does demonstrate that both engines see a limit at revs with oem manifolds
and does demonstrate.. that if your holding onto oem inlet manifolds .. and keeping revs sane.. and driving a heavy car ( like FC ) in traffic
.. then the 4 port engine is more usable
-- having more low down flexibilty and being a closer match up top to the limits of the inlet manifold with revs
.. dont get me wrong.. i love my turbo 6ports and have been using them for 15 + years
.. back in my rx2.. they dont have the issues with lack of TQ under 3k.. and rx2 is a light car
but in the rx7.. crippled further maybe by the 3.9 diff and the impco carb.. driven everyday on the street .. power between 2 and 3k revs is important.. not so power upwards from 6.5 K
the new motor im building for the rx7 is mild port ( 4 port ) and will be using 9.4 rotors to exploit the LPG octane and offset the slow burn at low rpms
i dont expect it to have the same top end.. i do expect it to be better under 3k
..motor i pulled out of my daily couple of days ago is 6p end plates.. G middle plate ( t2 ) and 8.4 rotors ( and turbo oil pump )
manifold was modded t2 with mods to the TB secondary delay to make them work as boost secondaries
mods to the TB are necessary to try and recover the lost bottom end below 3000 rpm due to the all aux ports open
( note my setup has low down woes exacerbated by a 3.9 diff.. and an impco LPG carb )
however,, engine is very sweet from 3 K up.. and does have a little bit more top end than the equiv 4 port / mild port with same rotors
( which i have also run about 5 years ago )
however,, with both setups.. was also blessed to have first used a custom log inlet manifold
( using a t2 bottom as a basis )
and the difference between the 6p and the 4p in the top end is much more marked with that type of manifold
-- indicating to me .. that t2 manifolds are restrictive to the peak power up top past 7000 on both engines ( esp. the 6 port )
.. but do help substancially down low on the 4 port engine
my surmise from all this.. the 6p has a later. wider spread of power potential that is cut short by the various methods to make manifolds fit
ie
- s4 6p inlet manifolds may retain the bottom end but may lack diameter to feed the top end and taper off even earlier
,, and brings issues where they wont seal the ACV passage under the primary runners
( if you have used the better t2 primary plate )
and will require a custom turbo relocation
s4/5 turbo inlet manifolds modded to suit on a 6p engine will have a larger bottom end hole ,,up to 3K but hold power to 7- 7.5 K
( when the turbo 4 port motor tends to taper at about 6.5 k )
custom log manifold / single blade TB
.. will lose substancial power under 2k.. will have made it all up by 4K ... and .. at least in my setup.. have a noticable bump in power above 6.5k up to 8500
( where i back off with standard rotors )
note the log manifold is very subjective to design and volume
.... mine is still running somewhere on a 6port resi engine
( also on LPG turbo and with the tall middle plate )
and was a stab in the dark .. but it does demonstrate that both engines see a limit at revs with oem manifolds
and does demonstrate.. that if your holding onto oem inlet manifolds .. and keeping revs sane.. and driving a heavy car ( like FC ) in traffic
.. then the 4 port engine is more usable
-- having more low down flexibilty and being a closer match up top to the limits of the inlet manifold with revs
.. dont get me wrong.. i love my turbo 6ports and have been using them for 15 + years
.. back in my rx2.. they dont have the issues with lack of TQ under 3k.. and rx2 is a light car
but in the rx7.. crippled further maybe by the 3.9 diff and the impco carb.. driven everyday on the street .. power between 2 and 3k revs is important.. not so power upwards from 6.5 K
the new motor im building for the rx7 is mild port ( 4 port ) and will be using 9.4 rotors to exploit the LPG octane and offset the slow burn at low rpms
i dont expect it to have the same top end.. i do expect it to be better under 3k
07-29-12, 12:16 AM
#3
That is a lot of great information!
It looks like I will be using the 4 port irons with the low comp rotors so I have some low end, and I will save the 6 ports for a 9.4 turbo build.
I did plan on using the stock turbo inlet manifolds on either irons, just port match the LIM to fit on the 6 port irons. Also planned on stock revs as well.
I would like to see the results from the engine you plan on building, make a thread when the time comes?
Sent from my iPhone using my finger.
It looks like I will be using the 4 port irons with the low comp rotors so I have some low end, and I will save the 6 ports for a 9.4 turbo build.
I did plan on using the stock turbo inlet manifolds on either irons, just port match the LIM to fit on the 6 port irons. Also planned on stock revs as well.
I would like to see the results from the engine you plan on building, make a thread when the time comes?
Sent from my iPhone using my finger.
07-29-12, 04:23 AM
#4
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ive had both
..motor i pulled out of my daily couple of days ago is 6p end plates.. G middle plate ( t2 ) and 8.4 rotors ( and turbo oil pump )
manifold was modded t2 with mods to the TB secondary delay to make them work as boost secondaries
mods to the TB are necessary to try and recover the lost bottom end below 3000 rpm due to the all aux ports open
( note my setup has low down woes exacerbated by a 3.9 diff.. and an impco LPG carb )
however,, engine is very sweet from 3 K up.. and does have a little bit more top end than the equiv 4 port / mild port with same rotors
( which i have also run about 5 years ago )
however,, with both setups.. was also blessed to have first used a custom log inlet manifold
( using a t2 bottom as a basis )
and the difference between the 6p and the 4p in the top end is much more marked with that type of manifold
-- indicating to me .. that t2 manifolds are restrictive to the peak power up top past 7000 on both engines ( esp. the 6 port )
.. but do help substancially down low on the 4 port engine
my surmise from all this.. the 6p has a later. wider spread of power potential that is cut short by the various methods to make manifolds fit
ie
- s4 6p inlet manifolds may retain the bottom end but may lack diameter to feed the top end and taper off even earlier
,, and brings issues where they wont seal the ACV passage under the primary runners
( if you have used the better t2 primary plate )
and will require a custom turbo relocation
s4/5 turbo inlet manifolds modded to suit on a 6p engine will have a larger bottom end hole ,,up to 3K but hold power to 7- 7.5 K
( when the turbo 4 port motor tends to taper at about 6.5 k )
custom log manifold / single blade TB
.. will lose substancial power under 2k.. will have made it all up by 4K ... and .. at least in my setup.. have a noticable bump in power above 6.5k up to 8500
( where i back off with standard rotors )
note the log manifold is very subjective to design and volume
.... mine is still running somewhere on a 6port resi engine
( also on LPG turbo and with the tall middle plate )
and was a stab in the dark .. but it does demonstrate that both engines see a limit at revs with oem manifolds
and does demonstrate.. that if your holding onto oem inlet manifolds .. and keeping revs sane.. and driving a heavy car ( like FC ) in traffic
.. then the 4 port engine is more usable
-- having more low down flexibilty and being a closer match up top to the limits of the inlet manifold with revs
.. dont get me wrong.. i love my turbo 6ports and have been using them for 15 + years
.. back in my rx2.. they dont have the issues with lack of TQ under 3k.. and rx2 is a light car
but in the rx7.. crippled further maybe by the 3.9 diff and the impco carb.. driven everyday on the street .. power between 2 and 3k revs is important.. not so power upwards from 6.5 K
the new motor im building for the rx7 is mild port ( 4 port ) and will be using 9.4 rotors to exploit the LPG octane and offset the slow burn at low rpms
i dont expect it to have the same top end.. i do expect it to be better under 3k
..motor i pulled out of my daily couple of days ago is 6p end plates.. G middle plate ( t2 ) and 8.4 rotors ( and turbo oil pump )
manifold was modded t2 with mods to the TB secondary delay to make them work as boost secondaries
mods to the TB are necessary to try and recover the lost bottom end below 3000 rpm due to the all aux ports open
( note my setup has low down woes exacerbated by a 3.9 diff.. and an impco LPG carb )
however,, engine is very sweet from 3 K up.. and does have a little bit more top end than the equiv 4 port / mild port with same rotors
( which i have also run about 5 years ago )
however,, with both setups.. was also blessed to have first used a custom log inlet manifold
( using a t2 bottom as a basis )
and the difference between the 6p and the 4p in the top end is much more marked with that type of manifold
-- indicating to me .. that t2 manifolds are restrictive to the peak power up top past 7000 on both engines ( esp. the 6 port )
.. but do help substancially down low on the 4 port engine
my surmise from all this.. the 6p has a later. wider spread of power potential that is cut short by the various methods to make manifolds fit
ie
- s4 6p inlet manifolds may retain the bottom end but may lack diameter to feed the top end and taper off even earlier
,, and brings issues where they wont seal the ACV passage under the primary runners
( if you have used the better t2 primary plate )
and will require a custom turbo relocation
s4/5 turbo inlet manifolds modded to suit on a 6p engine will have a larger bottom end hole ,,up to 3K but hold power to 7- 7.5 K
( when the turbo 4 port motor tends to taper at about 6.5 k )
custom log manifold / single blade TB
.. will lose substancial power under 2k.. will have made it all up by 4K ... and .. at least in my setup.. have a noticable bump in power above 6.5k up to 8500
( where i back off with standard rotors )
note the log manifold is very subjective to design and volume
.... mine is still running somewhere on a 6port resi engine
( also on LPG turbo and with the tall middle plate )
and was a stab in the dark .. but it does demonstrate that both engines see a limit at revs with oem manifolds
and does demonstrate.. that if your holding onto oem inlet manifolds .. and keeping revs sane.. and driving a heavy car ( like FC ) in traffic
.. then the 4 port engine is more usable
-- having more low down flexibilty and being a closer match up top to the limits of the inlet manifold with revs
.. dont get me wrong.. i love my turbo 6ports and have been using them for 15 + years
.. back in my rx2.. they dont have the issues with lack of TQ under 3k.. and rx2 is a light car
but in the rx7.. crippled further maybe by the 3.9 diff and the impco carb.. driven everyday on the street .. power between 2 and 3k revs is important.. not so power upwards from 6.5 K
the new motor im building for the rx7 is mild port ( 4 port ) and will be using 9.4 rotors to exploit the LPG octane and offset the slow burn at low rpms
i dont expect it to have the same top end.. i do expect it to be better under 3k
I'm gonna buy BumpStart's book when it comes out!..great stuff man!..Kudos!
(sent from my laptop using my Bifocals and a nightlight)
