I am going to be building an 88 s4 daily driver soon, and i want to get some info that will be usefull during my build. i have searched and found some info but want more. i want to clean up the engine bay but keep the ac and power steering. Emissions can go MO has passed a new law coming up really soon. As far as Exhaust what can i do, im used to turbo cars , never had to deal with the 5th and 6th ports before. I am building the engine and will be giving it a street port. I want to get rid of any thing possible, less stuff that can fail under the hood , as long as it wont interfear with the ac or idle. i want the car to be reliable and semi powerful for an Na. please give me some good input from the big NA guys out there. help would be greatly appreciated
thank you john

 

anyone know of a really good thread to read? basically from what i have found
need to keep bac valve for idle when car is under load, block off all emissions crap. keep thermowax for high idle during start up, ditch air pump, get dual belt. with the port acuators must keep cats for backpressure, or pay for racing beat exhaust, that will provide performance and backpressure fo the actuators. How does this sound so far, its gay that i cant just bust the guts out of the cats for an exhaust. any help or comments?

 

Yep, sounds like you've got it pretty much figured out. Keep the thermowax and BAC for driveability, the rest can go. And you need either cats or the RB presilencer to work the aux ports. Or you can operate them electronically, but thats a PITA. If you have the money, its much better to just get the RB dp/presilencer combo. I think its 250-300 and comes with everything you need, except maybe a gasket or 2.
You can also find them used sometimes as well.

 

john, did you buy something?

 

no but ive found a few na s around town with blown motors, i will have one soon though, i have a s4 na block to tear down and build

 

john seems like me and you pretty much have the same ideas, i figure turbo is not the way to go for me, so i am looking for a good n/a to start off with, and not do to much stuff to it. just to drive and have fun with.

 

im all turbo ive got a t2 i just want a daily driver, but ive had an na before there still a blast to drive.

 

what is the potential whp power for an s4 NA motor street port with no emissions and racing beat exhaust?

 

190ish give or take 10 ( is that not the general consensus?)

 

that would be great i thought it would be around 140 or so, what have people gotten with sim set ups

 

anything else i need to keep under the hood for smooth running besides thermowax and BAC, i found a car quicker than i thought antone have an
NA porting template they could trace on paper for me?

 

190 is extremely generous for an S4. I think you're looking at more like 170-175 with a streetport and RB exhaust. A good mod the S4 is to put the VDI S5 intake manifold on it. It requires just a bit of grinding to get it to fit right.

 

What I did for a template was go to Mazdatrix website and look under their porting section- http://www.mazdatrix.com/faq/port6p.htm

I printed their pictures out and measured the port on the picture compared to the port on my engine. I used the ratio from the two and applied it to the scribe marks on the printed page. I then made my own scribe marks based off those measurements. Does that make sense? I basically stole Mazdatrix design...
Double check that you stay away from the oil control ring and the corner seal path.

 

Why not then just swap in two T2 or maybe FD turbo housings in?

 

You could swap in TII intermediate housing but I like porting a 6 port better. I don't think an FD would swap in without mods to the cooling passages and other areas.

 

For an complete s4 (s4 rotors and intake) you are looking at probably 160 max without fuel tuning. With a standalone you could see in the 180s with a good tune and a good port job.

 

not lookin to get crazy with turbo housings and stuff just building a simple daily driver NA. I did look at racing beats templates they are all for turbo motors. who has templtes for Na s

 

were do you find street port templets for the 6port engine

 

great question?????????????????????????????????????????? ????????????????????

 

http://www.mazdatrix.com/toolport.htm

 

good reading anyone ground out the exhaust sleeve on the 6 port engines before

 

I wrote this piece a while back. It doesn't explain very well but you get the idea...

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/good-bye-exhaust-diffuser-595350/

 

doesn't seem to hard to cut and grind those out, much cheaper than turbo housings

 

Well you wouldn't need to buy turbo housings, just the diffuser inside of the housings.

 

thats what i mean ill be tearing the engine apart this week, maybe ill take some pics of the porting on this na engine and the removal of the diffuser