85se stock.Can i keep stock FI and do a streetport?
11-18-16, 01:59 PM
#1
Junior Member
Thread Starter
Join Date: Feb 2015
Location: AZ
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
85se stock.Can i keep stock FI and do a streetport?
trying to keep the car stock looking but give it more power. Around 200-220hp yet still retain the fuel injection. What can i do?
im new as you can already tell. Thank you for the advice in advance. Hoping I can take the car to rxforyour7 in tucson when there is an opening.
im new as you can already tell. Thank you for the advice in advance. Hoping I can take the car to rxforyour7 in tucson when there is an opening.
11-19-16, 04:17 AM
#2
Old [Sch|F]ool
200-220hp is asking a lot from a street ported GSL-SE.
It's also asking a lot of the stock computer, and I hope j9fd3s comes along because he's played with these more than I have. I think the main limitation is the computer runs out of AFM resolution and fuel injector timing at the same time.
I have made 200hp with GSL-SE injectors on a street port (not a 6 port) but the injector duty cycle was near 100%. The stock computer won't do that. Going to larger injectors won't do much unless you can also get a correspondingly larger AFM since AFM position and injector duty cycle are directly linked. Maybe there is a BMW AFM that is larger and you could try 1000cc injectors and tune air/fuel ratio with an adjustable fuel pressure regulator (use FC primary rail, mount regulator to firewall).
If I were going to try to do what you want to do, the very first thing I'd do would be to put a series 4 N/A intake manifold on it. The common N/A FC intake, not the VDI manifold. The GSL-SE intake is a huge restriction once you have an engine that can make that kind of power. Port matching will be required, the FC runners are a different size and a different height, you'll have to put epoxy in the top of the runners in the lower manifold.
Also, eliminate the 6 port actuator shafts, they represent a huge restriction in the port runners. I've never bothered with doing anything with the port in the engine as far as a filler, I just remove the sleeve. Was always too nervous about anything in there coming loose and falling in or rotating closed.
Also, series 4 or 5 N/A rotating assembly. Your'e going to need RPM, and 3mm seals don't like RPM and the 9-pin rotor gears don't like RPM either, and they are hard on stationary gears. The 12-pin rotor gears solve a lot of problems and the 2mm seals solve the rest of them.
It's also asking a lot of the stock computer, and I hope j9fd3s comes along because he's played with these more than I have. I think the main limitation is the computer runs out of AFM resolution and fuel injector timing at the same time.
I have made 200hp with GSL-SE injectors on a street port (not a 6 port) but the injector duty cycle was near 100%. The stock computer won't do that. Going to larger injectors won't do much unless you can also get a correspondingly larger AFM since AFM position and injector duty cycle are directly linked. Maybe there is a BMW AFM that is larger and you could try 1000cc injectors and tune air/fuel ratio with an adjustable fuel pressure regulator (use FC primary rail, mount regulator to firewall).
If I were going to try to do what you want to do, the very first thing I'd do would be to put a series 4 N/A intake manifold on it. The common N/A FC intake, not the VDI manifold. The GSL-SE intake is a huge restriction once you have an engine that can make that kind of power. Port matching will be required, the FC runners are a different size and a different height, you'll have to put epoxy in the top of the runners in the lower manifold.
Also, eliminate the 6 port actuator shafts, they represent a huge restriction in the port runners. I've never bothered with doing anything with the port in the engine as far as a filler, I just remove the sleeve. Was always too nervous about anything in there coming loose and falling in or rotating closed.
Also, series 4 or 5 N/A rotating assembly. Your'e going to need RPM, and 3mm seals don't like RPM and the 9-pin rotor gears don't like RPM either, and they are hard on stationary gears. The 12-pin rotor gears solve a lot of problems and the 2mm seals solve the rest of them.
Last edited by peejay; 11-19-16 at 04:20 AM.
11-20-16, 10:45 AM
#4
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,802
Received 2,575 Likes
on
1,830 Posts
my old GSL-SE is still around, its tempting to buy it back...
i tried a bunch of stuff on that car and here are my findings.
1. yes you can do a street port and keep the stock EFI or
2. find an FC engine and put that in. essentially Mazda did a street port for the FC, and they also upgraded the seals, rotors, and other bits. the S4 NA engine is a bit of an oddball, due to the EGR, but the S5 block is 100% plug and play with the GSL-SE intakes, even the emissions ports will function. the S4 blocks off the Air Control Valve, it will never ever pass smog anywhere ever.
3. buy a Racing Beat street port exhaust. we used to think this exhaust wasn't enough, but we're now running it on Bridge, and Peripheral ports, and its fine. it comes in one box, and its quiet too.
4. the stock GSL-SE ecu, and fuel system will be completely maxed out with just the FC engine and the exhaust. you can get a little more fuel by playing with the AFM, but you might as well just change the ecu.
4a. you would be running this ecu fuel only, so it should be pretty simple to tune it. only 2 injectors means you don't need much ecu to run it. plus you get to remove the AFM (hint buy an E bay cone filter adaptor, and some pipe and just bolt the adaptor to the stock airbox, and use the pipe to go to the stock hose). plus plus, you could upgrade to 1000cc injectors, or newer style ev14's later.
4b. or you could bump the fuel pressure. i've been wanting to try this for a while, apparently atomization gets better with more pressure, so not only do you get more fuel, it SHOULD have a better mixture quality too, so hopefully mileage would also improve
5. for ignition buy a new cap, rotor and wires. run Rx8 leading spark plugs. trailings should either be stock GSL-SE, Rx8, or the racing cold ones. the FC/FD plugs are junk.
6. a stock clutch is fine. if you have an S5 engine the stock flywheel is ok. with an S4 engine a lighter flywheel is nice, on the street i like the steel one. if your car is really light the AL is ok.
7. the S4 NA intake does add hp, something like 10hp. bolts right on.
so what do you end up with? with the GSL-SE intakes you end up with a car that is quiet enough to drive every day, and with the 6 ports hooked up makes peak torque around 3k and peak power around 6500, so it has a big fat power band. you can take it to the track and run all day without having to touch it, and it'll get good mileage when you're not beating on it.
in other words its FUN and easy.
i tried a bunch of stuff on that car and here are my findings.
1. yes you can do a street port and keep the stock EFI or
2. find an FC engine and put that in. essentially Mazda did a street port for the FC, and they also upgraded the seals, rotors, and other bits. the S4 NA engine is a bit of an oddball, due to the EGR, but the S5 block is 100% plug and play with the GSL-SE intakes, even the emissions ports will function. the S4 blocks off the Air Control Valve, it will never ever pass smog anywhere ever.
3. buy a Racing Beat street port exhaust. we used to think this exhaust wasn't enough, but we're now running it on Bridge, and Peripheral ports, and its fine. it comes in one box, and its quiet too.
4. the stock GSL-SE ecu, and fuel system will be completely maxed out with just the FC engine and the exhaust. you can get a little more fuel by playing with the AFM, but you might as well just change the ecu.
4a. you would be running this ecu fuel only, so it should be pretty simple to tune it. only 2 injectors means you don't need much ecu to run it. plus you get to remove the AFM (hint buy an E bay cone filter adaptor, and some pipe and just bolt the adaptor to the stock airbox, and use the pipe to go to the stock hose). plus plus, you could upgrade to 1000cc injectors, or newer style ev14's later.
4b. or you could bump the fuel pressure. i've been wanting to try this for a while, apparently atomization gets better with more pressure, so not only do you get more fuel, it SHOULD have a better mixture quality too, so hopefully mileage would also improve
5. for ignition buy a new cap, rotor and wires. run Rx8 leading spark plugs. trailings should either be stock GSL-SE, Rx8, or the racing cold ones. the FC/FD plugs are junk.
6. a stock clutch is fine. if you have an S5 engine the stock flywheel is ok. with an S4 engine a lighter flywheel is nice, on the street i like the steel one. if your car is really light the AL is ok.
7. the S4 NA intake does add hp, something like 10hp. bolts right on.
so what do you end up with? with the GSL-SE intakes you end up with a car that is quiet enough to drive every day, and with the 6 ports hooked up makes peak torque around 3k and peak power around 6500, so it has a big fat power band. you can take it to the track and run all day without having to touch it, and it'll get good mileage when you're not beating on it.
in other words its FUN and easy.
Last edited by j9fd3s; 11-20-16 at 10:49 AM.
