High-Flow Exhaust & 6 Ports
#1
Full Member
Thread Starter
High-Flow Exhaust & 6 Ports
Hey gang,
I bought my fc4 about 3 months ago. It had some exhaust problems that I fixed (Bad Cat). When fixing the bad cat I noticed that the exhaust manifold connected directly to the motor, i.e. no reactor.
There is no cat on the car now just a presilecer from another project and two high flow mufflers. The sound isn't bad.
I've read through the arcives and found that the secondary ports open by back-pressure from the exhaust. Because of the less restrictive air flow through the exhaust I don't think my secondary ports are opening when their supposed to.
Is there a way to check for this?
Or should I just do the 6 port thing anyway?
Also I've heard about adding an rpm switch and air pump to bypass this problem.
Does it work? Is it any better than porting?
A point to any other cheap HP mods would be appreciated.
Pyrocloud
I bought my fc4 about 3 months ago. It had some exhaust problems that I fixed (Bad Cat). When fixing the bad cat I noticed that the exhaust manifold connected directly to the motor, i.e. no reactor.
There is no cat on the car now just a presilecer from another project and two high flow mufflers. The sound isn't bad.
I've read through the arcives and found that the secondary ports open by back-pressure from the exhaust. Because of the less restrictive air flow through the exhaust I don't think my secondary ports are opening when their supposed to.
Is there a way to check for this?
Or should I just do the 6 port thing anyway?
Also I've heard about adding an rpm switch and air pump to bypass this problem.
Does it work? Is it any better than porting?
A point to any other cheap HP mods would be appreciated.
Pyrocloud
#2
REINCARNATED
iTrader: (4)
what part of tampa. I'm in clearwater.. in regards to your post
You said you have a series 4? (86-88.5)? well in that case yes backpressure is was makes your 5th and 6th ports work. try putting some grease on the actuator rods.. they can be seen just above the exhaust manifold. go out a do a couple of passes revving past 4-5 thousand rpms. when you park see if the grease has moved. if not than they are not working.
let me know.. and i'm sure any of the guys would be more than happy to help you out.
-Markus
You said you have a series 4? (86-88.5)? well in that case yes backpressure is was makes your 5th and 6th ports work. try putting some grease on the actuator rods.. they can be seen just above the exhaust manifold. go out a do a couple of passes revving past 4-5 thousand rpms. when you park see if the grease has moved. if not than they are not working.
let me know.. and i'm sure any of the guys would be more than happy to help you out.
-Markus
#3
Full Member
Thread Starter
Checked it out
Well,
I checked it out and their not moving.
This area in the motor compartment is filthy.
I'll try to post some pics tonight.
In reply: actually I live in Gulfport.
What's going on in the area? Any clubs?
I checked it out and their not moving.
This area in the motor compartment is filthy.
I'll try to post some pics tonight.
In reply: actually I live in Gulfport.
What's going on in the area? Any clubs?
#5
TII 4 SALE!
You can either wire them open, which leave's you with less low end power, but you get more top end... or else you can get a pre-silencer from racing beat that will still open them up. I have heard about electronically opening them up, but it is a big job.. and I know nothing about it.
#6
Eat Rice Don't Drive it.
iTrader: (3)
Re: Checked it out
Originally posted by Pyrocloud
Well,
I checked it out and their not moving.
This area in the motor compartment is filthy.
I'll try to post some pics tonight.
In reply: actually I live in Gulfport.
What's going on in the area? Any clubs?
Well,
I checked it out and their not moving.
This area in the motor compartment is filthy.
I'll try to post some pics tonight.
In reply: actually I live in Gulfport.
What's going on in the area? Any clubs?
try cleaning them. I found one of mine was stuck now they vboth work ok.
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#8
Full Member
Thread Starter
Getting’ on it tomorrow
I'll remove the actuator and clean that whole area tomorrow.
Is there anything else I should do while that area is exposed?
I know that everyone has probably heard this one but, is wiring the actuators open worth the low end loss?
So many people in the area!
My fc4 has some damage in the front and passenger qrt pan. So I'm not really sportin' it ya know. Wainting for some extra scratch.
After I fix the body damage, joining the MRCCFL sounds like a great idea.
I had no idea it was this big!
Is there anything else I should do while that area is exposed?
I know that everyone has probably heard this one but, is wiring the actuators open worth the low end loss?
So many people in the area!
My fc4 has some damage in the front and passenger qrt pan. So I'm not really sportin' it ya know. Wainting for some extra scratch.
After I fix the body damage, joining the MRCCFL sounds like a great idea.
I had no idea it was this big!
#9
Rabbit hole specialist
iTrader: (11)
It's best just to fix the system and use it as Mazda had designed.
The only reason to wire them open is you haven't been able to fix the problem. But to wire them open means you had to get the sleeves to rotate (therefore unsticking them if they were stuck), so you're already halfway to fixing them.
The only reason to wire them open is you haven't been able to fix the problem. But to wire them open means you had to get the sleeves to rotate (therefore unsticking them if they were stuck), so you're already halfway to fixing them.
#12
Seduced by the DARK SIDE
Join Date: Apr 2001
Location: Orange Park FL (near Jax)
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If backpressure activation is impractical, Kevin at www.RotaryResurection.com has a writeup in his tech section "airpump 6PI". It's cheap & crude but effective and elegant in it's simplicity.
To see that they open I tee in a pressure guage with a tee so I can blow in the tube & see at what pressure they open.
Then I extend the tee'd line inside the car & go for a drive to see when it hits that pressure.
To see that they open I tee in a pressure guage with a tee so I can blow in the tube & see at what pressure they open.
Then I extend the tee'd line inside the car & go for a drive to see when it hits that pressure.
Last edited by SureShot; 05-14-03 at 07:58 AM.
#15
Full Member
Thread Starter
Ah the power of cheese!
What is the backpressure sensing tube?
This tube is not hooked up. Someone welded it to the end of the header bracket and never hooked it up.
Therer are two hoses attached to the metal down tube.
I assume that the small one works the actuators. What does the big hose do?
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