because under full throttle the injectors hve more pressure behind them, therefore the fuel come out of the injector better. Have you ever seen that comercial for the stp fuel treatment stuff? it show how clogged injectors tend to release fuel in spurts, which is exactly what they are doing when he is at a low throttle the fuel is not spraying evenly like it should. that is why the car tends to bucks and lacks low end power.

 

you guys also have to keep in mind that these cars have very low torque to them with a very high redline. These cars don't like to drive slow, they have very little torque at those rpms, so they are not going to drive well. And also i forgot who said it but these car do have very large throttle bodies. They are going to be very responsive, and will always have little traits to them like that.

 

not so, na makes about 100lb-ft of tq at 3k rpm where a s2k makes about 50 and teh s2k has no such problem, just comparign the numbers we have way better low end. its the car in not proper running condition thats causing this, liek i said, wear on the drive train , fuel and tps sensor will all effect this...

 

oh i agree but, if you think about it 100 ft/lbs of torque really isn't much. and these people are talking about low rpms like 2 k and that only has 50 ft lbs of torque..that isn't much

 

That's the sort of opinion I'd expect from someone totally ignorant of the rotary engine, but not from an owner! Yes, compared to a big piston engine the rotary is short on torque, but that's because it's a small engine! Compare it to another small engine and you'll find it's got a perfectly acceptable amount of torque. Saying an RX-7 "doesn't like to drive slow" is nonsensical, it's quite capable of going as slow as any other car. A drive my car (the heaviest 7 made remember) in crawling rush hour traffic every day. I find it no more difficult in these conditions than any other small-engined car I've driven. The bucking problem refered to in this post is entirely to do with the crappy TPS, not a lack of torque. As long as I keep the throttle above the TPS's cut-off point, I can happily crawl along in second gear at about 1000-1200rpm. No bottom-end torque? I don't think so!
And regarding the "large" TB, at small throttle inputs, only one Ø45mm throttle is being used. That's quite small!

 

Just do the easy things first. With no air leaks and idle & TPS settings good, a mostly stock rotary will purrrr. If the trans is in neutral, the throttle should pick up smoooth. Then you may go after driveline backlash.

 

When the throttle is completely closed (and engine speed above 1500rpm) the ECU shuts off the fuel injectors to save fuel. All EFI engines for the last 20-odd years have done this. When the ECU detects you opening the throttle (via the TPS) it switches them back on, restoring power to the engine. Obviously you only want a tiny throttle opening when the injectors come back on otherwise it’ll cause the power to come in too hard, causing bucking. This problem is much more noticable at very low speeds because the throttle is kept very close to the TPS's cut-off point. For some reason Mazda can’t seem to design a TPS that can do this properly, and the fuel arrives when the throttle is too far open for a smooth transition. My 84 Cosmo had the same problem and I’ve heard FD drivers make the same complaints. All have the same type of TPS. Those who convert to aftermarket EFI (which will use a different TPS) say the on-off throttle transition is much smoother.

 

Hmm none of the automatics(including my sister's) had that buckling issue. I wonder if a lighter flywheel would reduce the bucking effect for manual trannies.
Speaking of bucking I was driving my buddies 98' TT Supra and it was just as bad as my 90GXL when it comes to 3mph driving.

 

The bucking would be nicely damped by the torque converter. It'll still be doing it, you just can't feel it.It actually makes it worse to to reduced rotational inertia.

 

hehe off topic but where did your buddy get a 98 supra?

and as for the problem...i also believe that sounds like partially clogged injectors that flow well at high pressure and drip and sputter at low pressure. i havent experience that with an rx, but it sounds similar to a chevy i played with that had tb injection. a tb cleanup and clean injectors got it going nicely.

 

Yeah I figure since automatics are attached to flex plates which is even lighter than an aluminum flywheel, that it would buck less. But I forgot about the torque convertor which might help smooth things out a bit.

 

This thread is similar to NZconvertible: https://www.rx7club.com/forum/showth...threadid=35204

 

Did you want one of those too? He bought it for $38K at Auto Nations. Spend 2gs hopping it up turning 0-60 in about 3.2 secs. He never had a chance to dyno or see the 1/4 because he wrapped it while stupidly racing an SS. He just went out got himself a Z06, and that one didn't buck the night I drove it.

 

ok my dads 2 liter saab has a lot of torque..i can dump teh clutch at idle and it walks itself out everytime, i can't do that with my rx. Also generally with any car that has a high redline like an rx gennerally doesn't have much low end power. just my two cents on that matter.

I am just trying to help these people. i had the same problem i dumped like two cans of injector cleaner and it fixed my problem.

 

That's really interesting, I'd always wondered why you could hold the throttle right on the transition and it would sound like it'd dropped a rotor......but I didn't think it actually was! My Cosmo did exactly the same thing. I just thought the TPS was rooted (probably was) and was surprised when my 7 did the same thing. Anybody know more about this? Six Rotors? Ted?

 

I don't think anyone mentioned that the motor/diff mounts maybe bad...

 

I dont have any real input but the fact that it does redline high means that it is setup to rev high, not low. Just a simple drawback of having a sports car I guess.

 

i guess i will go ahead and put some fuel injector cleaner in and do a couple of high rpm runs.

 

oh and if it is my injectors is it best to get new ones or clean the ones in there now?