Rotary Engine Building, Porting & Swaps All you could ever want to know about rebuilding and porting your rotary engine! Discussions also on Water, Alcohol, Etc. Injection

Is Exhaust Only Porting Ok?

Thread Tools
 
Search this Thread
 
Old Jul 30, 2003 | 12:35 AM
  #1  
GoRacer's Avatar
Thread Starter
Senior Member
 
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
Default

In one of the threads I read the Racing Beat only offers exhaust port templates. Intake porting can raise or mess up (lumpy) the idle. I'm not sure what good intake porting would do when the FD is allready turbocharged. Would there be much of a difference? Do I need to do both? Can I just do a exhaust only large street port? Am I making any sense?
Old Jul 30, 2003 | 08:22 PM
  #2  
Apex13B's Avatar
Senior Member
 
Joined: Nov 2002
Posts: 1,679
From: Colorado Springs
Default

Its gotta eat well if its gonna **** well
Old Jul 30, 2003 | 10:33 PM
  #3  
GoRacer's Avatar
Thread Starter
Senior Member
 
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
Default

Aren't race cams in pisstons exhaust only, with the exception of VTEC?
Old Jul 30, 2003 | 10:44 PM
  #4  
Silver Ninety Three's Avatar
Senior Member
 
Joined: Oct 2001
Posts: 1,675
From: Clifton, NJ
Default

Racing beat sells intake templates as well. You could port just the exhaust. We have done it on some stock cars jsut to help the turbos spool faster. I rather do intake as well though.
Old Jul 30, 2003 | 10:56 PM
  #5  
dr0x's Avatar
Member
 
Joined: Oct 2002
Posts: 54
Default

Kinda silly not to do the intake, especially since you have all the tools sitting there and the engine apart. I dont think youd regret it
Old Jul 31, 2003 | 01:14 AM
  #6  
88fc3sw/hx83's Avatar
Senior Member
 
Joined: Jun 2003
Posts: 223
From: OREGON
Default

Race Cams are NOT exhaust only in piston cars. They usually have a higher lift and duration for the intake and exhaust valves - they try to make it idle like a bridge !
Old Jul 31, 2003 | 01:44 AM
  #7  
GoRacer's Avatar
Thread Starter
Senior Member
 
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
Default

I thought race cams only changed the high rpm or exhaust and only VTEC was capable of both low and high end or intake/exhaust? ...if that's not true, what's the deal with VTEC?



Well I might want to pass smog, don't want to sacrifice low end or have lumpy idle so that's my resoning for exhaust only. So is the best choice: Mild Street for intake and Race street for exhaust? Am I confusing myself? Oh I won't be doing the porting, most likely it will be Mazdatrix if I don't go with Pineapple.
Old Jul 31, 2003 | 02:46 PM
  #8  
RotaryRocket219's Avatar
Senior Member
 
Joined: Oct 2002
Posts: 378
Default

VTEC is just valve timing electronically controlled, its changes the valve timing in the higher rpms to make peak power.



I'd do the intake ports too, I don't think low end will be sacrificed to much if you just do it moderately.
Old Jul 31, 2003 | 08:20 PM
  #9  
Apex13B's Avatar
Senior Member
 
Joined: Nov 2002
Posts: 1,679
From: Colorado Springs
Default

I also think that you'll regret not porting the inlet ports, and the idle is not lumpy at all with a small street port.



"Race" cams are usually at least a half-inch plus of lift on intake and about .490 exhaust on the lobe, anything less is bullhsit street cam
Old Jul 31, 2003 | 09:08 PM
  #10  
GoRacer's Avatar
Thread Starter
Senior Member
 
Joined: Aug 2002
Posts: 840
From: O.C. - CA.
Default

ok, so then that just leaves: Should I port match intake/exhaust or is there any benefit to a larger exhaust port (small street intake & large street exhaust port)?



All times are GMT -5. The time now is 10:19 PM.