84RX7'nSTi

I took my completely stock '85 GSL SE (w/72K miles) to the track yesterday. The track was extremely busy. We got to the track at 8 AM and by the time we made it through inspection it was 1 PM. I knew with 400 cars there, I was not going to get too many runs in.

Down to business. My first pass was 17.79 @ 79.53 mph w/ 2.560 60ft (missing the second gear shift). And my second and final pass was 17.44 @ 78.23 mph w/ 2.460 60ft (missing the third gear shift). I know I can improve on the ET by not missing shifts and getting a slightly better launch. However, what stands out is the poor MPH.

I am new to RX-7's, but I would think that the SE should produce better #'s. My old competely stock '03 Miata Club Sport (6spd) ran 15.90 @ 84.50 w/ 110whp and weighing virtually the same as the SE. I was expecting similar results.

I have not driven another SE, but my 13B seems to be flat at full throttle. I does not seem to accelerate any better with full throttle than it does with a quarter throttle? Is it possible my auxilary ports are not opening?

I don't know, any thoughts?

Mike

shm21284

That sounds like it could be a possiblity... the ports not opening.

The SE should rund a low 16, similar to your miata. A buddy of mine had an SE and I had a 12a with Dellorto, RB intake and Exhaust, which ran a 15.7, and his was only 3-4 car lengths behind after a quarter mile (never took the SE to the track).

Check the valves.

Zyrano

swap out the exhuast system, that would make a hugh difference, cats from the 80s were really restrictive. Also check your fuel filter, plugs and stuff.

84RX7'nSTi

How do I go about checking the valves? I know that some people compare the six ports to a honda v-tec. My SE does not resemble that at all during full throttle at high rpm.

The air filter and plugs are new. I need to check out the rest of the items.

I know an exhaust system is a must, but I wanted to get a good baseline before adding performance parts.

Mike

Rotary Weasel

I am running similar times in my SE as well, it has plenty of power at low to mid rpm but seems to make more noise than power at high rpm: dropping in a new 13B this next summer should solve that of course

RacerX7fb

Six-port actuation is alot smoother than a VTEC switchover, just about unnoticable.
Checking it is simple. While under the hood, look for the two actuators below the lower intake manifold like in the picture.

You should be able to press the rods in fully with your thumb. If you can't, they are stuck. If they open partially but do not return they are stuck. Do not hit with a hammer to loosen, force them, etc. The rod is NOT a straight solid piece, half is similar to a coiled cable and it flexes. When an actuator is stuck it's typically because the sleeve is gummed up inside the side housings. Best fix is to remove the LIM for a full cleaning.

Now warm up the engine. By hand pull on the throttle to rev the engine anywhere above 4000RPM (ths is if you are by yourself, if you have a friend with you he can press on the accelerator and watch the tach.)
You should see the actuator rods begin to depress and be fully open along the way to WOT. They should shut when you are off the accelerator.

Yes determining 6-port actuation can be done while the car is parked! No need to grease the rods and drive. The engine does not need to be under load, especially when the car is fully stock with cats. People may say so otherwise.

Rotary Weasel

thanks for that! I know what i'm going to be doing today.....

84RX7'nSTi

Thanks RacerX7fb!

I just spent the last hour dissembling the intake on the SE. I noticed that the bottom two butterfly's in the throttle body are open. And that there is no linkage attatching them to the other throttle body linkage? So it looks like they are always open? I don't know if this has anything to do with anything?

I was able to press both actuators down with my thumb and they both retracted when I released pressure. But, when I started the car and rev'd the motor they did not depress? I will try it again and make sure I was getting the engine over 4,000 rpms.

Mike

RacerX7fb

Make sure that the split-air pipe ( the 1/2" tubing from the main cat) and hoses are all attached and in place.

gsl-se addict

iTrader: (3)

Those butterflies are suppose to be like that. They will close when the car is cold to keep the secondaries shut off.

If the rods for the 5/6 ports are working smoothly, you may need to rev it quicker to get them open. Also check the small vacuum line that goes from the back of the intake manifold to the check valve near the main cat. The system uses exhaust back pressure from here to operate the 5/6 ports. I had a hole in my vac tube causing mine not to open.

riceburner1r2001

iTrader: (4)

hey this is dave with that blue 7 u talked too. u just need more practice and you,ll be fine and it was great talking with u. i could hook up at all i spun from 1 all threw 4th and almost grabbed 5th i smoking threw all gears

84RX7'nSTi

Hey Dave,

I'm glad you found this thread. It was great meeting you! I greatly appreciate all the knowledge and information that you shared with me during the long inspection line.

Man, I could never find you in the pits and I never got a chance to see you run.

I definitely need more 1/4 mile practice in my RX-7's. I know next time my E.T.'s will improve. The MPH just kills me though. I have searched and read that the SE's should be good for 15.9-16.1 @ 84-85mph.

I double checked the 5/6 port actuators at 4,000 + rpm and a quick full throttle blip. The actuators do start to engage, I can imagine at full throttle while pulling rpm they open fully.

Mike

Kentetsu

Check your timing too. That can make a big difference in overall performance.

LokiRx7.1

iTrader: (1)

You're working with an older car, simply because of age your car may be slower than it was when it rolled off the assembly line. So many things could be wrong all of the above could be correct. You may not be getting good compression, your plugs or plug wires may need replaced, your throttle body and/or injectors could be filthy. You may not be getting good vacuum which would not allow your port accuators to properly operate. So many things could be just ever so slightly be off, I dont know if your looking to put this car to the track and or turn this into a performance application, the engine will need rebuilt, just a good investment. You'd be amazed at the simplest of things I've seen that affect performance so negatively. A guy came to me with a '66 Chevy II and he couldnt figure out why his car was slower than it had been. He was absolutely sure it was his timing but he said he checked that and it was fine. The first thing I did was pop the hood, it was an old 6-banger and I opened the air cleaner, guess what? Dirty air filter, he came back and said he was still having trouble. I did a Carb rebuild and it solved the problem. His dirty air filter had allowed a minuscule particle of dirt into his carb and it was trapped in his carb somewhere. I reccomend you just do a general tune up, replace everything that is cheap first. Just a rule of thumb

FB II

OHHHH NOOEEESSSSSS, if you plan to do anything to this engine you need to rebuild it first!!!!


first and foremost... you really should check your compression. it's a good thing to know as a baseline for what really needs to be dealt with. IF that checks out good, then you have the biggest possible problem out of the way. so you know to start looking at fuel and ignition. take it one step at a time... and you will get this baby rockin down the track.