Porting an NA fc
10-20-16, 09:11 AM
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Porting an NA fc
Hey everyone! Winter is quickly approaching and im looking to get myself into something to keep me busy, and what better way that building a brapppping rotary?
Heres my current situation, I have a 1988 fc na convertible that needs rebuilding. I've always loved the signature braaaping idle that ported rotaries have, and would love to build and own one myself. I've done some research on porting but can't seem to find much in the way of required parts in order for everything to work. I'm fairly new to the rotary world especially when it comes to porting. So basically, I'm looking towards an NA Bridgeport, not looking to go crazy with the horsepower (not sure how much an NA can make), but it's also not going to be driven daily so the rough drive of a Bridgeport is no biggy. I know I'm gonna need a standalone, bigger fuel pump, injectors, exhaust, emissions delete... what else am I gonna need in the way of parts to be able to accomplish this?
Thanks
Heres my current situation, I have a 1988 fc na convertible that needs rebuilding. I've always loved the signature braaaping idle that ported rotaries have, and would love to build and own one myself. I've done some research on porting but can't seem to find much in the way of required parts in order for everything to work. I'm fairly new to the rotary world especially when it comes to porting. So basically, I'm looking towards an NA Bridgeport, not looking to go crazy with the horsepower (not sure how much an NA can make), but it's also not going to be driven daily so the rough drive of a Bridgeport is no biggy. I know I'm gonna need a standalone, bigger fuel pump, injectors, exhaust, emissions delete... what else am I gonna need in the way of parts to be able to accomplish this?
Thanks
10-20-16, 10:04 AM
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Engine, Not Motor
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Bridgeports are like the nastiest race cam you can put into a piston engine. 100% overlap.
Here's the thing. If you build an NA bridgeport with that 6 port engine, you're making an engine that will make peak power somewhere around 9000 RPM. Combining overlap with way too much port area. It will be rather disappointing below 4000 RPM. Stonger than the stock port, but not by a lot. You're going to need to either highly modify (by gutting the dynamic chamber) the stock NA intake or switch to a TII intake (needs port matching) or a short runner style with ITBs.
It's going to be loud. Insanely, ridiculously loud. If you want it quiet, then all the intake and exhaust restriction necessary is going to compromise power dramatically.
It will get terrible fuel economy.
Bridgeports are the most difficult port to tune. Widely overlapping load points, the lack of a distinct idle area on the map, vacuum that basically goes away when the throttle is cracked.
Did I mention it will be loud?
A healthy bridgeport on an NA engine can do power in the high 300s in race trim. But we are talking completely unstreetable here unless earplugs are involved for anyone in or around the car.
The best suggestion here is to do some research on bridgeports. Lots of info around these forums. You can use my name as a key word, as well as "peejay" and you'll find others with experience as you go long.
Also, there's the thing about putting all this time, money and effort into an NA bridgeport, dealing with the poor fuel economy, the noise and all the downsides. Then seeing your car is slower than a stock TII with an upgraded exhaust.
Here's the thing. If you build an NA bridgeport with that 6 port engine, you're making an engine that will make peak power somewhere around 9000 RPM. Combining overlap with way too much port area. It will be rather disappointing below 4000 RPM. Stonger than the stock port, but not by a lot. You're going to need to either highly modify (by gutting the dynamic chamber) the stock NA intake or switch to a TII intake (needs port matching) or a short runner style with ITBs.
It's going to be loud. Insanely, ridiculously loud. If you want it quiet, then all the intake and exhaust restriction necessary is going to compromise power dramatically.
It will get terrible fuel economy.
Bridgeports are the most difficult port to tune. Widely overlapping load points, the lack of a distinct idle area on the map, vacuum that basically goes away when the throttle is cracked.
Did I mention it will be loud?
A healthy bridgeport on an NA engine can do power in the high 300s in race trim. But we are talking completely unstreetable here unless earplugs are involved for anyone in or around the car.
The best suggestion here is to do some research on bridgeports. Lots of info around these forums. You can use my name as a key word, as well as "peejay" and you'll find others with experience as you go long.
Also, there's the thing about putting all this time, money and effort into an NA bridgeport, dealing with the poor fuel economy, the noise and all the downsides. Then seeing your car is slower than a stock TII with an upgraded exhaust.
10-20-16, 11:35 AM
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Here's the thing, i actually finished a t2 swap in the same car a few months ago only to find out the i was sold a junk motor with apex seals that were destroyed on the second rotor. So I do have a t2 motor with parts available for whatever I need. Was going to just going re build that and port that. Guess what im trying to ask, what would be my best option, for 250-300hp and obtain that signature brap in the idle. All I'm looking for here
10-21-16, 09:26 AM
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Rebuild the TII engine. Limits of the stock turbo is about 250HP with a good tune. A mild hybrid brings that up to 300HP.
Anything you do to port the idle to make it "brap" is going to destroy fuel economy, reduce vacuum, and make the car difficult to tune. If you just cut a little bridge or drill some holes to create the overlap then you won't be doing much in the way of flow or power addition, just causing all the disadvantages. Do you want fuel economy in the single digits for a "brap" noise?
Anything you do to port the idle to make it "brap" is going to destroy fuel economy, reduce vacuum, and make the car difficult to tune. If you just cut a little bridge or drill some holes to create the overlap then you won't be doing much in the way of flow or power addition, just causing all the disadvantages. Do you want fuel economy in the single digits for a "brap" noise?