Stargun

I have two questions.

First my 13b seams to run fine up to 5k rpms then it starts to blow smoke. My friend and I have been discussing the color of the smoke, it is a blueish white color. Not really blue enough to be oil but not really white ether. I am leaning toward bad seals but I am wondering if anyone else has any ideas.


My second questions is how important is the air pump, the previous owner removed it.


Thank you for your help in advance.

Pele

iTrader: (28)

That's typical sign of bad oil control rings... Especially if it does it when the engine is cold.
How fast are you losing oil and what do your spark plugs look like after a couple thousand miles?

The air pump on 1989-1991 N/A RX-7s activates the aux ports and VDI systems.

The air pump on ALL RX-7s supplies air to the catalytic converter for emissions purposes. If there is a cat and no air pump, the cat will fail, fall apart, and clog up your exhaust.

Side note: Since the air pump on 1984-1988 N/A RX-7s supplies air to the catalyst. If there is no catalyst, then you'll get no back pressure on the exhaust. The back pressure is what activates the aux ports on the earlier cars. You can convert the early cars to operate the aux ports off of air pump pressure like a 1989-1991 model... If the air pump was still there.

So tell us a little more about your car. Year, Model, Other mods, etc.

canonize-ryda

my 86 na has no cat, one precat and stock mufflers. no air pump either and would u think my actuators are opening? i no its takes about 2.1 psi to open them. and one more thing do i need to get rid of my precat? or will it be ok

Stargun

Sorry lame newbness not putting in the details of my car.

I have a 89 s5 n/a convertible. As for mods I can't really tell you I just got it and the previous owner couldn't really tell me about the car. I have discovered it has an after market manifold back exahust, an electric fan and no air pump. Interior is ok, body is great, engine is ruff.

It was overheating then dropping to normal just to over heat again. I swapped out the thermostat and it stopped over heating.

I was looking at a shop manual and noticed that the air pump was missing from my car and it looked like it was important.

So from the sound of it the air pump is important.

PS what is VDI?

Pele

iTrader: (28)

Why have precats when you don't have the main cat?

Precat doesn't need air though. Main cat did.

But without the cats, you don't have much backpressure, so I doubt your aux ports are opening.

It's short for Variable Dynamic Intake. VDI is a part of the S5 (1989-1991) intake system.

You know how you can get better mileage if you follow a semi truck kinda close on the highway. The semi cuts down the air resistance to your car, so your car uses less energy to keep moving. The truck would also get a slight boost in mileage (Not really noticeable.) because you're pushing air against the truck instead of the truck creating a suction behind it.

The car's intake and exhaust can work like that. One puff of air going to a rotor can follow another puff of air. They kinda help each other along. Same with the exhaust, which is why that different manifold is on there. The pipes have been cut to a certain length so that the pulses of hot exhaust gasses meet up at the right time.


The VDI helps that effect. At low speeds, a longer intake runner (pipe of the intake manifold that goes to an individual rotor) is best so that the intake air pulses can help each other through.

At higher RPM, a shorter runner is better so that more air can get into the engine faster. At that point, it's less useful to have the VDI system and more helpful to have less restriction.

Stargun

I just did the champagne test and i got No bubbles. Also when the throttle is depressed the coolant is sucked down. So it seems me coolant seals should be good. Any Ideas on why I get the smoke over 5k rpms? Also it seems to lack power, and sometimes I get a back fire and a little smoke when I lift off the gas at any rpms.

Thankyou

canonize-ryda

well your year of engine the s5 needs the air pump to open your 5th and 6th ports. without the air pump u will probally experience loss of power after about 4k when your ports should normally open. probally same reason for the white smoke to much exhaust not enough ports to get all of it out.