the power of porting an engine?
03-07-02, 02:50 AM
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the power of porting an engine?
i was wondering how much power will street porting a na motor will punch out to. does anyone have any experiance with this, please i would like to know. also i couldnt find what the diff between a bridge port and a street port is..can any of u guys explain the differences ....bridge vs. street?
perhaps pros/cons?
i have an opportunity of getting a turbo for my NA but i dont think its gonna be worth getting a turbo for a na...just rather sell my car and buy a turbo and upgrading that...too much hassle for my situation rite now..and more $$ to put into.
so i decided to port my rebuilt motor first and see how it goes from there. thanks guys.
88se, bonez intake, N1 exhaust, t2 hood, rebuilt 1k miles, bonez racepipe. much more to come...
perhaps pros/cons?i have an opportunity of getting a turbo for my NA but i dont think its gonna be worth getting a turbo for a na...just rather sell my car and buy a turbo and upgrading that...too much hassle for my situation rite now..and more $$ to put into.
so i decided to port my rebuilt motor first and see how it goes from there. thanks guys.
88se, bonez intake, N1 exhaust, t2 hood, rebuilt 1k miles, bonez racepipe. much more to come...
03-07-02, 03:31 AM
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a bridge port kills the power below 4000 rpm and make massive tourqe and hp above 4000 rpm to about 10,000 rpm. but you will need to shorten your intake runners and get alot of fuel mods and balence the engine. It will work if you can live with bad gas milage and no low rpm power. but is upper rpm will blow your shorts off.. a street port on a N/A will only be worth it if you have full exuast and port the intake good.( exrude hone) both of them would make monsterus HP if you use 89 N/a rotors and torbo intake and side housings...
03-07-02, 02:06 PM
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Mild/Extended Port
The advantage is anywhere up to 10% more power can be reached, with the torque range extending higher up the rev scale. Up to approx 200hp is attainable with other mods
Bridge Port/J Port
In both of these examples, an additional port is cut into the plate alongside the original port - which is usually slightly modified as well. A bridge port is simply a diluted version of a J port and makes roughly 10% less power - but with slightly better bottom end torque. Both bridge and J port modified engines rely on a highly efficient intake and exhaust - without which they can actually drop power. However, in some cases peak power can be up to 50% improved - with a maximum of around 240hp (with a street exhaust/intake) to 260hp (with a race exhaust/intake). A J ported rotary can rev to 8000-9000 with few problems, but torque does start to come in higher at around 3500. The trade-offs are more severe than a mild port - both economy and drivability are poor, and flames can be expected belching from the exhaust too (especially with a carby induction set up). A bridge port is also the first stage where brap-brapping exhaust noise starts to become an issue.
Monster Port
A monster port is an even bigger and badder version of a J port. In this *****, an additional huge port that extends into the face of the rotor is ground into the plate and mods to the rotor housings are also required.
A monster makes good torque from 4000-9000 rpm and a 100% power increase can be achieved. A maximum of around 280hp can be extracted from an engine equipped with a race exhaust and intake. Drivability is all but gone.
Peripheral Port (aka PP)
Peripheral porting is the most extreme form of rotary breathing enhancement - and it's (by far!) the loudest. Low rpm torque, drivability and economy are completely lost but it's just the ticket for peak power - often, over 100% improvements can be gained over standard. (Note that with really good engine management, a PP can be driven on the street quite successfully - but you'll need injector end-point setting facilities and other such management features.) The effective torque band is also moved way up the tacho - beginning from around 5000 and building to a theoretical 10,000 rpm! (And building an engine to rev this high is another matter!) A PP won't idle much below 1800 rpm either - so by all accounts, it's a high revving and highly stressed engine that ain't for the street. However, in excess of 300hp can be found at the flywheel when combined with a race intake and exhaust.
In order to construct a PP, the standard side ports must be filled or blocked off somewhere upstream in the intake. Then, relatively large diameter ports are machined through the rotor housing (yes, on its periphery!) and into these are inserted aluminium sleeves that are shaped for best results with a die grinder. A sealant is then used to form a seal between the housing and the sleeve
The advantage is anywhere up to 10% more power can be reached, with the torque range extending higher up the rev scale. Up to approx 200hp is attainable with other mods
Bridge Port/J Port
In both of these examples, an additional port is cut into the plate alongside the original port - which is usually slightly modified as well. A bridge port is simply a diluted version of a J port and makes roughly 10% less power - but with slightly better bottom end torque. Both bridge and J port modified engines rely on a highly efficient intake and exhaust - without which they can actually drop power. However, in some cases peak power can be up to 50% improved - with a maximum of around 240hp (with a street exhaust/intake) to 260hp (with a race exhaust/intake). A J ported rotary can rev to 8000-9000 with few problems, but torque does start to come in higher at around 3500. The trade-offs are more severe than a mild port - both economy and drivability are poor, and flames can be expected belching from the exhaust too (especially with a carby induction set up). A bridge port is also the first stage where brap-brapping exhaust noise starts to become an issue.
Monster Port
A monster port is an even bigger and badder version of a J port. In this *****, an additional huge port that extends into the face of the rotor is ground into the plate and mods to the rotor housings are also required.
A monster makes good torque from 4000-9000 rpm and a 100% power increase can be achieved. A maximum of around 280hp can be extracted from an engine equipped with a race exhaust and intake. Drivability is all but gone.
Peripheral Port (aka PP)
Peripheral porting is the most extreme form of rotary breathing enhancement - and it's (by far!) the loudest. Low rpm torque, drivability and economy are completely lost but it's just the ticket for peak power - often, over 100% improvements can be gained over standard. (Note that with really good engine management, a PP can be driven on the street quite successfully - but you'll need injector end-point setting facilities and other such management features.) The effective torque band is also moved way up the tacho - beginning from around 5000 and building to a theoretical 10,000 rpm! (And building an engine to rev this high is another matter!) A PP won't idle much below 1800 rpm either - so by all accounts, it's a high revving and highly stressed engine that ain't for the street. However, in excess of 300hp can be found at the flywheel when combined with a race intake and exhaust. In order to construct a PP, the standard side ports must be filled or blocked off somewhere upstream in the intake. Then, relatively large diameter ports are machined through the rotor housing (yes, on its periphery!) and into these are inserted aluminium sleeves that are shaped for best results with a die grinder. A sealant is then used to form a seal between the housing and the sleeve
