littlebit421

so you mean running the split air pipe off the header at a smaller diameter,

what i was sayin from your statement was, header--->small straight pipe--->factory y pipe(where it goes to duals) then muffler of your choice,

what i did on my 88 n/a was factory manifold--->2 1/2 or 3/4 cant remember--->to factory y pipe---> straight through mufflers.

CAUTION IT WILL BE REALLY REALLY LOUD, so if you dont want to **** off everyone in the neighbor hood I would not suggest this.

sorry Im a little confused.

RotaryRocket88

iTrader: (7)

The exhaust components aren't really important other than the fact that cats will build more backpressure to help open the ports. The split air pipe is the tube running along side to bring air to the main cat. The aux. port actuator line comes off of it.

Cnicklegend

here's the pictures of where the actuators should be...

littlebit421

ok i follow you, now that we have that cleared up, I have a question, on my s5 vert i can feel a little boost at about 5000 rpm's, is that the vdi or the secondaries kicking in suddenly. my exhaust is manifold-->straight pipe 2 3/4--> resonator--> factory y pipe with factory mufflers. I probably really need to check my secondary acuators.

RotaryRocket88

iTrader: (7)

Those bolts may be JB welded in there. It may be worth it to just source a used LIM that hasn't been tampered with.

VDI @ 5200 RPM.

I'm not sure why you're concerned with your exhaust. S5 aux. port actuators are controlled by a solenoid that directs air from the airpump; just like the VDI actuator. The 6PI and VDI solenoids are on the rack. Only S4s (and 1st gen GSL-SEs) use the exhaust backpressure method.

littlebit421

I dont know either we were on a exhaust topic so i just ran with it I get that way, my fault. ill shut up now. i appreciate all the info.

Red_Rotor

iTrader: (3)

sorry for the misleading info, its all what i hear bouncin around. but for me id rather not waste a couple hundred on manifold fabing and just go turbo. u know, the fast rx7s

cab91089

iTrader: (3)

An N/A engine can put out a lot of power if you do the right mods. And turbo charging the N/A is not just about the swapping the exhaust manifold on and its turbo. It requires all the intake manifolds, port matching, drilling into the front cover, custom making other parts, etc. and when its said and done you will probably spend more then just a few hundred dollars. I am planning on making my N/A into a 6port turbo but before I do that I am trying to get the N/A running and doing mods to it until Fall rolls around. Then I pull the engine back out and get it rebuilt with half bridge and continue in the process of making a 6 port turbo out of the N/A block.

Red_Rotor

iTrader: (3)

wasnt referring to make a 6 port turbo. i was talking about a swap. also i opened the vdi manually. i capped off the actuator and popped off the arm that controls the port and opened it up. now my 5th 6th ports plus the vdi are always open. noticed a big difference in top end power

littlebit421

what about low end, like driving around town normal did it effect driveability. I was thinkin about doin this also.

Red_Rotor

iTrader: (3)

Not ag all. Used to feel slugish in the high end until i did this. Idle is perfect and i still have the low end power i did before

RotaryRocket88

iTrader: (7)

Not this again...

How exactly do you think you have gained power by making the ports and VDI permanently open? All you've done is killed low-end and mid-range, and made the engine act like it has turbo lag. You're feeling like you have a sudden boost of power because the engine is now anemic for 5000 RPM.

See the line marked A) 200mm shorter? That's what happens when you wire the VDI open. Line D) 400 mm longer is when the VDI is closed (normally under 5200 RPM). Look at the torque difference between A and D from 2000-5000 RPM. It's 5-10 ft. lbs. you miss out on.

This is straight out of the Mazda S5 SAE paper. You can even see the '88 S4 intake manifold graphed on here.




And that's just the VDI! Forcing the aux. ports open all the time is even worse. Air velocity going into the engine decreases, and you lose even more torque under 3800 RPM.

I would not suggest it. See above.

Red_Rotor

iTrader: (3)

Mind u this is only temp till i can get some new actuaters. All the stuff for emissions n all that was hacked when i got the engine. The way i have it now feels better than what it was. Id rather have the power at high rpm. Im not drag racing. When i put it in 3rd on the freeway im not at 3k. So for the way i drive i need the power at the top. I didnt buy an rx7 for its tire roasting power anyway. Im just making the best with what i have.

Red_Rotor

iTrader: (3)

Is there a way to run vdi and the 5th 6th port actuators both on rpm switches?

RotaryRocket88

iTrader: (7)

I already posted this link earlier in the thread: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/activating-aux-ports-vdi-rpm-switches-907824/.

But there's no need to use RPM switches when an S5 ECU already does it.

Red_Rotor

iTrader: (3)

heres the situation. i have a full s5 engine in my s4. using s4 sensors and wiring harness. still using s5 tps. pre mixing since its the s5 omp and my harness is s4 still. so the actuators and all the emissions stuff were hacked up including the wiring harness when i got the motor. was in a time crunch since my car was in a buddies garage. so i worked with what i had ang got it running. not to mention i have a racing beat header with no cats to my dyno max mufflers. meaning no back pressure pipe for air pump. should i close both the vdi and 5th 6th ports? or leave the vdi open and close the others or what? seems like its doin great with the way i have it right now IMO

RotaryRocket88

iTrader: (7)

As a temporary measure, wiring the aux. ports and VDI open is probably the best route. Keeping them closed all the time is worse.

If you're using an S4 ECU and wiring, the RPM switch method I detailed out would be the best bet. An electric air pump may be used in place of the stock air pump I tapped into.

Red_Rotor

iTrader: (3)

id like to get my hands on an s5 ecu and harness. that way i can use my s5 maf sensor and my s5 instrument cluster as well. id have to get s5 injectors i think too.

pyrod27

iTrader: (9)

ressurect!!!!ok i have an 89 vert and it has solid pull all the way through rpm up to redline but does not have the power increase "jump" at any point.if i think my air pump is bad would this cause the 5th/6th ports not to open?

Red_Rotor

iTrader: (3)

ya the air pump i believe is what pushes air to the actuators that make the port sleeves turn to dish air to engine. did u check to see if the actuator arms move? maybe they are stuck shut

pyrod27

iTrader: (9)

yep they are stuck shut.plan on cleaning them over the weekend.one more question where do you guys get the gaskets for the UIM and LIM?oriellys, napa, and autozone dont carry them.

Red_Rotor

iTrader: (3)

Just use rtv gasket maker. Works good

pyrod27

iTrader: (9)

but thats the getto way....isnt there anywhere that sells them?

Zero10

I got mine from the local dealership. They didn't have them in stock but were able to get them in 1 business day and the price was right too, $4-$7/each.

pyrod27

iTrader: (9)

my 5/6th ports wernt working so i ordered some atkins sleeves. took it all apart replaced all of the gaskets fuel lines vacuum lines. so i pulled out the old sleeves and they wernt dirty at all.but the cables were for sure stuck with it all together. anyways i put it back together with the new sleeves made sure they turned just fine and buttoned everything up. they still didnt work. i replaced my dead acv and bacv while doing this.any ideas?