So I have an S5 vert daily driver that has just about had it, it's bone stock. I'm going to rebuild it soon but have had a hard time deciding exactly what to do...



engine must stay N/A

must use the oem S5 N/A intake manifold,TB, airbox, ECU, wiring harness, etc

I'm OK with changing injectors and adding a fuel pressure regulator

I'm willing to change the header, but want to keep it oem past the cats

I don't care about working aux ports or vdi, I'll just wire them open if need be

It must have a smooth drivable powerband, idle properly, start every time, etc

I should have to spend minimal time messing with it to get it to run properly

oh, and it should make about 300 hp





I was planning on just doing a street port on the 6 port, swapping the exhaust sleeves for TII ones, and calling it a day. Then I started thinking about maybe a TII center iron, then thought about just doing all TII irons. maybe a complete streetported TII motor with N/A rotors? how would the S5 N/A intake manifold stand work with that combo? who has ideas?

you will NEVER get anywhere close to 300 hp NA with what your mentioning/ requirements





you might make like 160 wheel hp wiht a street port and thats about it.... ( if your keeping stock cat back and ecu and intake)



the upper limit with good longivity and daily drivability is about 200 hp with a reliable setup that is very daily drivable



( bridge ports and exreme porting can get more but you generally lose low end power and makes hard for street driving)





only way u can get reliable 300 hp is with a turbo or super charger.

a stock port s5 NA with full rb street exhaust and an afc tuned for the proper fuel curve will make 160whp if everything i sworking correctly. i would hope a ported engine makes more power then this https://www.nopistons.com/forums/pub...IR#>/smile.png

go check out the dyno section

obviously I don't really expect to make 300 hp https://www.nopistons.com/forums/pub...>/rolleyes.gif

so why mislead the people that you came to for help?

Port the primaries/secondaries to open a little earlier, leave the aux ports alone they are already cut too high, and port the exhaust*. I would consider lower C/R rotors now that the keg is open, 9.0, 9.4,

A header and full exhaust*.



A direct port N20 kit, back out timing a little, and maybe colder plugs



I emphasised exhaust tunning to evacuate the the extra gasses the N20 will build. And you gotta do your math with N20. The airbox MAY be a restriction, but I dont think it will hurt to try and keep it with a good filter.



You should be approaching 300 hp with that setup and have a reasonably normal car.

keep it stock...

I have an '86 GXL I bought from a girl who's dad bought it for her nine years back. He ordered a low mileage engine from one of the Japan importers and rebuilt it himself (He's a mechanic up in Woodstock) and since the rebuild , 63k has been put on it. Runs like a charm. Never had it stall out or not start, no matter the weather. In fact, the only wrong things with the car is the transmission is 20 years old and not hiding it too well and my oil pressure gauge or sender (still not sure which) has gone bad and my pressure gauge keeps hopping in random ways, randomly.



Michelle said he replaced the seals with heavier duty ones, she always has warmed the car up, changed the oil on time, etc.



Rebuild it stock. Maybe do a slight port, and get a racing beat exhaust + cold air intake. You'll be fine, my car is 100% drivable and has no problem bitch-slapping the smirks off the local ricers' faces. I parked next to this totally ricer 1G Eclipse and he actually moved to another parking space.