I am getting a rebuild soon on my s4 na and plan on getting a streetport. my question is do i need a piggyback to run a large streetport? Or is the stock ecu sufficient? Also do s5 rotors give a power gain?

 

It's best to use a standalone. Megasquirts work well with N/A applications, and can be had for less funds than any other standalone on the market. I would not recommend using the stock ECU, you can't control ignition and fuel. You could run a piggyback, but compared to a standalone, it's limited in control.


S5 rotors do give some gain, but not alot. You are better off keeping the S4 rotors in.

 

A standalone is great, don't get me wrong, but whether the cost is going to worth it is another matter. Even a Megasquirt install is going to be expensive when done right and if you can't do the tuning, you're going to need to pay someone else at over $100 an hour to dial in the car.

A "large" street port on a 6 port engine will probably result in a slower car. The 6 port already has plenty of port so there is only a little work needed to clean them up. Most of the higher HP NA cars (minus those with bridge or peripheral porting) are on stock or nearly stock ports.

 

so a mild streetport would be better?

 

A mild streetport amounts to nothing more then smoothing out the runners and transition with only a few minor port timing changes. For a street driven car, it is probably the best choice.

Then again, a much better question is how much power do you want to make, what is the intended use of the car, do you care about low end torque, etc.?

 

ok my goal is 180whp, daily driven street car. low-end torque is always a plus.

 

I would leave the ports alone, or do a mild street port.

 

I just did a large street port on my built and very pleased with the results. I'm still using stock ECU and injectors. I didn't had a chance to take it for a dyno yet, but racing against a stock 6 port with RB exhaust all the way wasn't even close. 5000 rpm and beyond is the sweetest thing you will expereince on N/A form. It just felt like driving my old MR2 with 180 whp, but the engine has more to give on higher rpm and I'll find that out once I have a stand alone ECU.

 

Who did your port? ,How much was it? ,And how does it run on the stock ecu? Mods list please?

 

I did all of the porting and technically I have changed most of the vital parts of the car. i.e. polyurethane bushings, toe steer eliminator, converted my 4 lug to 5 lug, ghetto CAI, pineapple racing 6 port insert on the sleeve, s5 rotors on s4 engine, lightweight flywheel, OMP mod, gutted interior and more to list.

 

Using the stock ECU was fine it's almost the same as before, I got more low end torque when I connected the 6 port actuator at the air pump instead of the exhaust back pressure. Now the car is pretty consistent at 17 mpg but before that while breaking it in I was getting 13 then 15 mpg. I still have the stock exhaust manifold and I'll have the RB road race exhaust manifold once I have the EGT bung installed and probes in. I'm up here in Santa Clarita where are you in LA?

 

Now compare it to a stock S4 TII, which probably makes the same amount of power.

 

yeah i'm in shitty los angeles lol! Why? good to know it runs well on the stock ecu.

 

would love to take a ride in a large streetported or bridgy rx7.

 

Because the TII will be quite a bit faster due to all the midrange torque...

 

How much do TII put down stock? They maybe faster but dont last as long lol!
love all rotarys though na or turbo.

 

S4 TIIs put down 180HP stock, while S5 TIIs put down 200HP in stock form.

 

yeah but thats at the crank. i mean at the wheels?