I looked but couldn't find a specific answer to my question. I am about to get my
s4 tii motor. Tearing down and porting. They guy that is helping me out said he would do an aggressive streetport. What hp gains should I expect from that?? whp or just hp, please specify if you know the numbers. If you have a list of different ports and gains, or a thread with the info i would greatly appreciate it as well.

 

it depends on who is doing the porting and how well they do it the hp gains differ depending on the person porting it and the quality of the port job

 

it will vary on your set up as well, are you using the stock turbo, fuel system, igni, piggy backs or standalone?

(My friend had a 88 Turbo 2 with a B&B Street port and tune...this is all stock stuff btw...stock fuel pump, stock injectors..piggy backs S-AFC and AVC-R, FCD and THE STOCK TMIC, he had basic bolt ons...HKS filter with the HKS 3in DP going to a GP Sport 3in single exhaust no cat)

his quarter mile time was around 13.8ish but he blew the motor anyways...(that was due to not setting his idle correctly and it over heated and died)

but before all that he was killing modded SRT-4's kept up with a Base model C5 Vette on the freeway till 155 (His 1/4 was prolly faster than 13.8)

Rumor was he dynoed at 250rwhp on the stock s4 turbo with no wastegate porting (no idea how much PSI but the sucker pulled hard)

 

A large street port is also called an "extend" port by the Anzacs. Hp levels in the link are without boost.
http://www.turborx7.com/portingpictures.htm

Street porting
http://www.mazdatrix.com/engsp.htm
Bridge porting
http://www.mazdatrix.com/faq/portbp.htm
Exhaust porting
http://www.mazdatrix.com/faq/portexh.htm

Dyno comparison of boosted engines
http://www.catenet.net/dyno.php

Keep in mind that a large street port will probably not pass a state emissions test. While you may not currently have emissions testing in your area, you may need to sell the car, or at least the engine, if you move to an area that does have emissions testing and you plan on driving it on the street.

^ +1

Also, if the person doesn't know what he is doing, the engine will be ruined.

 

I keep posting this after evils link, and not because i dis believe anything evil says. He is in fact a vary wise and informed individual. I just believe that it is important to pull from multiple sources when determining a course of action.

http://www.mazdarotary.net/porting.htm

 

I completely agree with using multiple sources, but the information in your link is already included in the first link that I posted.