zero83

iTrader: (7)

I have a s4 n/a engine that I will be rebuilding soon. This is going in my DD, so I'm not looking to make crazy n/a HP. From what I have searched theres not much you really can do anyways unless you go bridge/PP and thats not happening

But since I have it torn apart I might as well do some porting. From what I understand there really is not a "streetable" intake, so I will just be doing the exhaust. My first question is about the exhaust sleeves in the housings. Can I still port the exhaust and use those or do I need to replace them with T2 sleeves to actually make a difference? And if I am going to remove them, how much louder is it really going to be?

I also will be needing an intermediate housing. Are there any benifits to swaping to one other than stock? Like using the T2 because intake ports are larger


Thanks If anyone has any suggestions feel free to post...I want to make this some what reliable but with a little kick

13bpower

You can do porting to the intake. As long as you stay within "street port" specs of a templet it will be very streetable. The exaust diffusers and be grinded out but it is a pain in the ***. If if you are going to leave the diffuser in I wouldn't bother porting the exhaust ports. If you remove the diffuser slight porting of the exhaust would be helpful. Just keep in mind you will be hurting power in the low RPM range where most daily driving is done. This will also lower your gas milage. Something to consider when it is going to be a DD.

If I was going to have a N/A as a DD I would just do a light streetport on the aux intake ports. I would also use FD rotor housings which have no diffuser and keep all other ports stock. That will give the best low end response and a nice bump in the top end.

flaco

iTrader: (7)

if your going to port it go ahead and do a nice big port. if you want small for that just dont do it

Derekcat

iTrader: (8)

Grab some Pineapple sleeve inserts. Make sure your 5th/6th ports open properly..

I wouldn't remove the exhaust diffusers unless you have a RB or stock exhaust [and I'm not sure how much help it would be on the stock..] With a full RB exhaust [headers/presilencer/catback] the car is still quiet, but it is an audible difference. [Diffusers or no]

ScrapFC

iTrader: (5)

Not much gain to be had porting an NA. I would do a nice cleanup port on the intake side, leave the exhaust ports alone, get the lightest flywheel you can stand and a proper exhaust. Definitely do some kind of aux port sleeves, whether Pineapple of Atkins. If you're really obsessed you can gain a bit more by porting/polishing the intake. If you focus on efficiency rather than trying to really hog things out you can have really excellent driveability, if not monstrous horsepower.

driftxsequence

iTrader: (8)

street port made a noticeable difference on my car. lost a little low end power but i wasnt sitting in traffic often so i didnt mind. the top end power was a lot stronger and pulled into higher RPMs. gas mileage was worse because i was taking it to redline for that feeling and sound more often.

zero83

iTrader: (7)

I already had the atkins sleeves on order, as well as a RB exhaust template. I think I will just order the intake one as well. The car is mainly used for work and back, which is only 10 miles one way and I never see traffic. So a little loss in low end and gas mileage isn't too bad.

I would like to take the car to an occasional autoX or track day soon. I know I have other areas to take care of other than the engine...but I have 209K on the original engine so I'm crossing this bridge first. Don't want to have a car with bad *** brakes/tires and a blown engine

RotaryEvolution

iTrader: (30)

removing the exhaust wing is about a 13-14% horsepower gain, just sayin'.

and free flowing intake and exhaust actually improves mileage, not decrease it. unfortunately these 2 things combined make for a loud car.

in stock trim these cars are rather constipated.

clokker

iTrader: (2)

My car farts in your general direction.

"Rather constipated" implies that application of a suitable laxative will unleash torrents of power, an event I still await.

REAmemiya_fan

Karack does make a good point though. You must think, in the NA 6 port you have the horrid port air flow around the actuator rods, then air going into the engine at 90* after smashing into a wall of nothing, then exiting through the diffused exhaust port into nothing more than an exhaust plenum of a manifold, through three sets of cats, and out through two non-straight through mufflers. Breathing through this engine is a difficult task. I'm not saying going with giant ports and straight pipe exhaust will solve all it's problems, but all the right things will allow an NA to make good power levels.

13bpower

When starting out with 110 wheel horsepower another 20-25 isn't exactly a kick in the pants. If you consider that most vehicles would not get nearly the same percentage increase from just opening up the intake and exhaust (see RX-8) then you will understand the wisdow and experience behind his words.

REAmemiya_fan

This. I always trust what Karack has to say. And Rotarygod.