2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Going from stock to street port

Thread Tools
 
Search this Thread
 
Old 06-22-15, 08:20 AM
  #1  
Senior Member

Thread Starter
iTrader: (4)
 
redheddude222's Avatar
 
Join Date: Dec 2008
Location: Evansville, IN
Posts: 261
Received 8 Likes on 5 Posts
Going from stock to street port

I searched around a little bit and couldn't find anything that answered my questions, so here I am.

I'm about to have my S4 TII engine rebuilt, and I'm having it street ported at the same time. My current setup is mostly stock. Emissions delete, OMP delete, twin scroll actuator deleted, and an aftermarket turbo-back exhaust.

Besides injectors and a new clutch, what else will I need to support the street port? Is Rtek 2.1 or another standalone my only option, or is there a "chip" or reflash that will work? I appreciate any help. I'm not new to rotaries, but I've never owned a ported one.
Old 06-22-15, 11:34 AM
  #2  
Sharp Claws

iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,107
Likes: 0
Received 41 Likes on 40 Posts
you don't need anything to support a streetport, the difference are in fact usually at most a 8% gain in peak horsepower which isn't enough on its own to warrant retuning unless the other mods are pushing it beyond that ragged edge. your turboback exhaust will actually make more of a difference than the porting will do and may allow the boost to creep to unsafe levels, so my advice is to have the wastegate modified or ported as well to keep the boost down.

now if you want to make a reasonable amount more power then yes, you would need a piggyback on your ECU or a standalone, bigger injectors, fuel pump and a way to monitor AFRs to be sure it is safe. boost pressure makes power not so much any other mods you make(mods have an effect but it is ALWAYS about how much air the engine is getting in and out which usually translates to a rise in boost) so always keep in mind the more boost you run over stock the more you have to make sure the engine is happy with it.

Last edited by RotaryEvolution; 06-22-15 at 11:39 AM.
Old 06-22-15, 11:38 AM
  #3  
Rotary Adrenaline

iTrader: (3)
 
sc0rp7's Avatar
 
Join Date: Dec 2004
Location: Kennesaw, GA
Posts: 564
Received 4 Likes on 3 Posts
I'd always recommend an rtek or aftermarket chip/ecu if exceeding stock boost levels. Also some way of custom tuning the air fuel for safety if you are in fact modifying the car.
Old 06-22-15, 07:01 PM
  #4  
Senior Member

Thread Starter
iTrader: (4)
 
redheddude222's Avatar
 
Join Date: Dec 2008
Location: Evansville, IN
Posts: 261
Received 8 Likes on 5 Posts
I hadn't planned on turning up the boost since I'm still on the stock turbo. It holds a steady 6psi with no boost creep right now, but I have an HKS FCD on it just in case.
Old 06-22-15, 07:39 PM
  #5  
Sharp Claws

iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,107
Likes: 0
Received 41 Likes on 40 Posts
an FCD is just like pulling a pin out of a grenade, waiting for you to release the handle.
Old 06-23-15, 09:36 PM
  #6  
Senior Member

Thread Starter
iTrader: (4)
 
redheddude222's Avatar
 
Join Date: Dec 2008
Location: Evansville, IN
Posts: 261
Received 8 Likes on 5 Posts
So my current plan is to upgrade to Rtek 1.8 and 750cc injectors. At what boost level does the stock S4 turbo become inefficient?
Old 06-24-15, 07:36 AM
  #7  
Sharp Claws

iTrader: (30)
 
RotaryEvolution's Avatar
 
Join Date: Oct 2003
Location: Central Florida
Posts: 5,107
Likes: 0
Received 41 Likes on 40 Posts
12-13psi
Old 06-24-15, 10:18 AM
  #8  
Rotary Enthusiast
iTrader: (1)
 
GrossPolluter's Avatar
 
Join Date: Feb 2012
Location: CA
Posts: 1,075
Likes: 0
Received 2 Likes on 2 Posts
The very first thingis you needed to open up your engine and are what is usable. I would consider high oil pressure regulator.

The 2nd thing is to have the s4 turbo modified. Not just ported, but the wastegate flapper valve needs to be bigger, then the hole needs to be drilled and ported bigger. A stock s4 with full exhaust boost spikes. Now a ported engine with full exhaust spikes worse! Good way to blow an engine. So far the only person I know that puts bigger flapper valves for our turbos is bnr.

I like the s5 turbo more. You will need the s5 manifold, turbo, gasket from manifold to turbo, and oil drain tube
Old 06-24-15, 03:59 PM
  #9  
Senior Member

Thread Starter
iTrader: (4)
 
redheddude222's Avatar
 
Join Date: Dec 2008
Location: Evansville, IN
Posts: 261
Received 8 Likes on 5 Posts
I'm having a shop do the rebuild and porting for me. I guess I'll be on the lookout for a different turbo then.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
sYnth.
Build Threads
0
08-19-15 06:27 PM



Quick Reply: Going from stock to street port



All times are GMT -5. The time now is 03:58 PM.