Very weak under 3500 RPM
 

Hey guys I was wondering why my 86 sport feels underpowered when im driving. I have to rev to 4-4.5k in order to keep up with traffic and that just owns my gas. Any suggestions on how to fix that? Maybe Tranny slipage?

Perhaps someone wired the 5th/6th ports open?


But what are you comparing it to? Is this your first rotary car? Because really, these things aren't powerhouses at low RPM, its just the way they are - alot of their power comes from the velocity at higher RPM's.

Mmm.. yea thats what i heard. Yea this is my first rotary car. But I was just comparing with oridinary piston engines and I was just wondering how come I have to rev so high in order to keep up with people who are driving regularly on the street.

Well, rotaries don't have much torque down low, but more than likely the 5th and 6th ports have been f*&%ked with.

Plus its more than likely that your car needs a grocery list of parts to make it run like it should. Meaning its been rode hard and put away wet, probably tired ot a bit by this point.

mmm.. how would i check for the 5th and 6th ports?

do a search with 5th 6th ports as keyword and you'll come up with mountains of info on things like using electric servos to open them, wiring them open, Pineapple racing sleeves......it goes on and on.

But you'll find them located directly over the exhaust manifold. You will see two vaccum solenoids that are (should be) connected to two "rods" that stick into the intake manifold.

does it feel like your clutch is slipping? you're car should be revving around 2.5k at 65mph in fifth depending on your rear ratio.

n/a rx7's don't have enough low end torque to zoom around in fifth (overdrive) in the city; strictly highway gear.

I have my 5th-6th ports wired open on my street-port, n/a and I don't see that much of a difference on the low end. ~rich

mm.. yea the clutch isnt sliping (although has a very high or late catch point. I just don't wanna waste so much gas blasting it all the way up to 4k. Thanks for the input guys

I actually get better mileage revving a little higher before shifting. I shift out of first at around 4 to 4.3k , 2nd to third at like 3.1, 3rd to fourth around 3.5 and then 4th to fifth until I reach my desired cruising speed (Fifth IS overdrive...)

I tried following the shift light and the owners manual recommendations, but it seems I get worse mileage.

All I'm saying is that it seems like when I shift at the light intervals, my tank doesn't go as far.

Also, never get a full tank of gas unless you're clocking mileage or going on a long highway trip. Gasoline isn't exactly light...

4k is not blasting... And when you watch most automatic cars, they shift gears around 3-4k unless you're barely touching the gas, and NO ONE does that.

The N/A 13b doesn't make a whole lot of power or torque (Though for it's size, it's amazing), but it really is the funnest way to have a lack of that torque. Accelerating feels like a wound up rubber band letting go, a sling-shot effect.

And can you please stop saying 'Mmm' at the start of each post? I'm gay, so I'm the only one who can do that! :-p

S4's 5th/6th ports are actuated by exhaust backpressure. What is the condition of the exhaust system, has it been modified, or had more recent cats installed. The 5th/6th ports are most likely to be the culprit, however rotaries are peaky by nature; if you've ever driven a two-stroke dirtbike you know exactly how a rotary feels. ;)

I'd also look at your TPS voltage and grounds.

Things to do on a newly aquired rotary etc:
Coolant flush, Oil/filter change, tranny fuid, diff fluid, air filter, fuel filter, belts, plugs and wires.
Check specs on TPS, O2 and MAF sensors, clean, adjust or replace accordingly.
Flush entire brake/clutch hydraulic system and bleed with NEW DOT 3+ fluid. Adjust clutch pedal rod to assure proper engagement point.

Remove intake manifild, check the vacuum lines and solenoids for cracking or damage, replace or remove if you dont have emissions to worry about.
Check injectors for leaks as well as pulsation dampener, replace any that are leaking or even better send to Witchhunter for cleaning and new o-rings and seals ($60 shipped with a couple day turn around) as well as replace the pulsation dampener as you dont know when it was last replaced. (Should be done every 80-120k)

Doing all of this will assure most of the potential issues are not problems causing bad things to happen. I pretty much do this to ANY car I get when I first do, in exception to certain things specific to rotaries.