VDI and 5th/6th port sleeves/actuator rods

mbuskuhl

mbuskuhl

New member
On the S5 2nd Gen...

I have seen this done on winning ITS cars... is it legal, and if so does it fall under emissions removal or ?

VDI - wired open

5th/6th port actuators removed, actuator rods removed and holes plugged, sleeves - assumed removed as they would have to be secured some way and if the rods are gone, sleeves must be as well.
 
I looked earlier at the GCR and did not see it. Just looked again.

This is the closest I could find, are you selling it under this rule below? I'm not looking for a debate, just an answer as to what rule is used to do what I initially posted, or is it illegal?

"Exhaust emission control air pumps, associated lines, nozzles, and electrical/mechanical EGR devices may be removed."​
 
Yeah, I just looked at the 08 GCR and didn't see anything. I could swear there used to be a specific allowance. Anyone else?
 
Check in the factory manual and see that this system is located in emissions section and is controlled by the air pump. Therefore legal to remove. Section F1-42.
 
With regard to the 5/6 ports, on the spec line:
5th and 6th intake port actuators and valves may be removed or disabled
 
Thanks for all the responses, looking on the spec line might have helped!

I need some more help though. I'm having an important email debate and needing this information to help win my/our case. For those that want to run NASA ever, we need to get this cleared up. NASA (PT Director and his "RX-7 experts") are trying to say wiring the VDI open is "modifying the intake manifold" and removing the 5/6th actuators, sleeves and rods is considered "porting".

The GCR states ... "5th and 6th intake port actuators and valves may be removed or disabled"

The actuators are plain and simple, we know exactly what those are. What specifically are the "valves"? The actuator turns the "actuator rod" which turns the "sleeve". I imagine the GCR wording of "valves" is intended to cover both the "rod" and "sleeve", correct?

Note, NASA does not follow IT rules and IT does not follow NASA. However, if IT says it's legal and IT also says no "porting or polishing" on rotary motors specifically, then clearly several experts agree removing the actuator/rod/sleeve is definately not "porting".

I'm attacking VDI seperately as it wiring it opens provides ZERO benefit, only hurts under 5500 RPM torque.
 
More than one way to skin a cat (grab the ears or a**):pJust wire the solenoid to hold it all open. Nasa is being a little bit of a jerk on this one I believe. Thats what you get with a dictatorship.
 
seckerich said:
More than one way to skin a cat (grab the ears or a**):pJust wire the solenoid to hold it all open. Nasa is being a little bit of a jerk on this one I believe. Thats what you get with a dictatorship.
Click to expand...
I'm pretty sure the VDI operates with positive air pressure, normally supplied by the emissions air pump. The solenoid switches the air to actuate the VDI. The ports work the same way. So if you've removed the air pump, you've got no way to hold these devices open. And I can't see any way that it would be legal to add a pump (electric?) to operate them. The S4 worked a little differently, with the ports operating off the exhaust pressure.
 
There is a way to make the VDI work without the air pump, it's just a PITA. Guys who do the S5 intake swap on to an S4 motor on street cars found a way with an RPM switch. Same thing with the 5th/6th actuators. They needed these to work for low RPM torque. Just hope the final ruling doesn't come back that you have to have the air pump on as well!

Here is a question, feel free to PM me if you'd rather not post and I will keep the source 100% confidential.

Has anyone done dyno testing to confirm if the 5th/6th sleeve and rod removal produces any gains? There is a small amout of material that is removed from the ports, is that enough to increase air flow to actually get a measurable increase? 1-2 rwhp, I can't imagine any more if even that.

Without a doubt, we can say wiring the VDI open provides ZERO gain as it is open at 5500 RPM already. Removing the 5th/6th actuators also does ZERO.
 
mbuskuhl said:
There is a way to make the VDI work without the air pump, it's just a PITA. Guys who do the S5 intake swap on to an S4 motor on street cars found a way with an RPM switch. Same thing with the 5th/6th actuators. They needed these to work for low RPM torque.
Click to expand...
Mark, can you point me to more info on this. My son's got a street car that needs it.

Thanks,
 
If at all possible just pull them out. The gains you make over 5500 far outweigh anything you lose below. You're not running the engine down there anyway...shouldn't be anyway.
 
C. Ludwig said:
If at all possible just pull them out.
Click to expand...

That's what I am lobbying NASA for. However, they are trying to contend removing the sleeves is considered "porting". None of us want to put them back in. An official decision is still pending.

What kind of gains, if any, are truly made by removing the sleeves and rods?
 
Would someone mind explaining what this is? Im still somewhat new to my 2nd gen and i am totally lost trying to follow this conversation.

Thanks

Wes
 
monsterbronco said:
Would someone mind explaining what this is? Im still somewhat new to my 2nd gen and i am totally lost trying to follow this conversation.

Thanks

Wes
Click to expand...

Wes,

The 6 port induction system (5th-6th ports) is on all 2nd Gens, 86-88 (S4) controlled by exhaust and 89-91 (S5) air pump. The VDI (Variable Dynamic Intake) is on the 89-91(S5) upper intake manifold as the 86-88(S4) had a completely different intake design.

5th and 6th Ports (Aux ports) and VDI
All non turbo 13B engines used in the 2nd generation RX-7 have a 6 port induction system. The 5th and 6th ports remain closed below about 3500 RPM, preserving air velocity and running more conservative port timings to help increase low end torque. After that, the ports open up and improve top end horsepower. If the ports are not working properly, you will loose quite a bit of top end punch (the commonly accepted figure is around 25 HP). To test them, first locate the actuators. They are located on either side of the ACV valve above the exhaust manifold. Looking from the passenger side of the engine compartment towards the drivers side, you will see two cylinders with rods sticking out from them. Those are the actuators. Smear some grease on the shafts and after your test drive look to see if the grease has moved. If it has, then the actuators are working. If not, something needs to be repaired. If the car was not driven at high RPM, then most likely the actuators have frozen from age. Removing them and applying penetrating lube usually brings them back to life. If the actual port valves are stuck, the intake manifold probably has to come off. The '89-'92 engines also have a Variable Dynamic effect Intake (or VDI). This is another valve in the upper intake manifold that opens above about 5000 RPM to allow the pressure waves generated by intake closing to travel through the secondary port runner to the opposite port and force more of the intake charge into that rotor. The valve remains closed at lower RPM to make the secondary runners longer, thus maximizing torque. This actuator is located on the drivers side of the upper intake manifold between the runners, just below the dynamic chamber (plenum box). It can be tested in the same way as the 5th and 6th port actuators. Just make sure you make several runs over 5000 RPM so that the intake valve can open.


Also Read here...
F42-47
http://www.rx7city.com/Manuals/89-91 Manual/Fuel_and_Emission_NA.pdf

Spend some time on RX7club.com in the 2nd Gen section and reading the FSM (online for free if you don't have one), you'll learn a lot about the car. And of course, get your hands dirty and work on it yourself. Both of these systems give the car benefit at low RPM (below 5000k or so), therefore in a racing application they are not needed and removed.
 
Official NASA ruling is in, technical bulletin coming....

VDI wired open and actuator removed - 0 points

5th/6th port actuators removed, rods removed, sleeves removed - 0 points

Any modification to the air flow in the 5th/6th ports (pineapple racing inserts, JB weld, etc) - dyno classification


Just like the IT rules!

:026::026::026::026:
 
You must log in or register to reply here.
Back
Top