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GSL-SE Aux ports vs FC and a hint of street porting talk

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GSL-SE Aux ports vs FC and a hint of street porting talk

Old 12-31-18, 08:30 PM
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GSL-SE Aux ports vs FC and a hint of street porting talk

Specimen is a 1980 model with a GSLSE drivetrain (with a SA transmission) and GSLSE suspension...

As I understand it, the Aux ports on an SE have a port timing of 70* ABDC with the FC being 80*. (Rotary Engine Illustrated) I have also read numerous times that street porting an 6-Port, especially as a novice... limited in the return on investment. I am considering Pineapple Racing or Mazdatrix template, but not purely dead seton it yet. My intention is to use a S4 or preferably S5 intake with DYIAutotune or similar ECU. This car is more of a weekend cuiser and not likely to see competition. I do not intend to touch the primaries, as I hope to keep the MPG at highway cruising "reasonable" but I don't mind dumping some fuel when I get into it. So the point of the story is I am not going for a dyno king but would like to hit 170 or so at the wheels. What would you do?
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Old 01-01-19, 04:09 AM
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Run a 4 port.

Changing the primary port timing will not affect fuel economy very much, do not worry about that.
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Old 01-01-19, 09:12 AM
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The cheapest route to your goal would be add a low boost turbo to what you have. 170whp on a 6 port isn't very commonly done and in my experiance you end up with an engine that makes peak power beyod the rpm that you want to run a stock ish engine.
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Old 01-01-19, 10:19 AM
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the best combination i have had in a 6 port, was an FC engine, GSL-SE intakes and a racing beat street port exhaust. not sure how much power it made, but it made it everywhere. there were a few combinations in the car and i can run down some of them:

S4 FC engine, SE EFI, RB single exhaust. butt dyno says it made very similar peak power, at slightly higher rpm, but it lost big below that.

GSL-SE engine with 9.7 rotors, SE EFI, RB dual, it gained power under 2000rpm, but lost a bunch over that.

if needed the S5 engine emissions passages are compatible with the GSL-SE, so in california i could run the GSL-SE intakes on an S5 block and it would emissions test like stock. the S4 blocks off the emissions and will never pass any emissions test anywhere ever.

in 2019, i would add an ecu and some larger more modern injectors. no smog guy has ever checked the ecu, and its fuel only so it would be simple to tune, AFM would get removed for something that looked like an AFM but wasn't

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Old 01-01-19, 11:03 PM
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Ideally, I would say start with one of the FC engines, but if you already have a perfectly good S3, then why not start there? Exhaust goes without saying, and the RB dual is the best off-the-shelf choice - assuming, it's not the ONLY choice. I would say go with your FC intake and standalone idea. I think that will take you a long way toward your goal. To that, I would probably also suggest a flywheel at some point in the mix. I also like the idea of modern injectors - just an FYI, Rx-8 ones are nice and they are also cheap. I would say do the porting last, at which point you can either upgrade the S3 rotating assembly to S4 or S5, or you can just start with a complete S4 or S5 block. As for porting, maximize your primaries and secondaries, but I'd refrain from messing with the auxiliaries.
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Richard Miller (01-02-19)
Old 01-02-19, 09:16 PM
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Personally I have not been enthused with FC-based 6 port anything.

GSL-SE on left, FC on right.

FC just simply closes way too damn late to have any fun. By the time the engine is spinning fast enough to not be losing compression to the massively late port, it is choking on the lack of flow.
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Old 01-03-19, 12:51 PM
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I would street port the primaries. That and exhaust porting is where all the gains will be made as like others have said the aux ports( on the FC anyway) already close too late. I used the Pineapple Racing templates on mine with their EP2 template on the exhaust of turbo rotor housings. I really don't see any benefit to not touching the primaries. I averaged 20mpg before. I average 18 to 20mpg now depending on the season( winter blend fuel hurts my mpg). I have hit 23mpg on pure interstate/highyway but most of my driving is probably a 80/20 hwy/city mix. This is on the stock ecu. I figure I could get better on a standalone.

Last edited by Dak; 01-03-19 at 12:53 PM.
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