I think he has an engine swap though. different ratios and all.

 

Hello everyone.I just purchased a 90gtu about 6 weeks ago. it only has a header as far as mods go. My car also tops out at 110mph?? can anyone give some insight as to how i need to check ports 5 0r 6, where they are,etc...My knowledge is limited to honda's or at least smaller 4 cyl.(i know i know)
I just got a haynes today so ill be reding up...
thanks.

 

sorry about the blurry pictures, it is dark here and hard to focus.

The first picture should be recognizable

The second one (although blurry) is closer to the car

The third one is of the rear actuator with it highlighted

The fourth one is of the front actuator with it highlighted.

Yes, those are springs to help them open at the right spot with a modified exhaust.

I hope that helps you

 

so, from what i've read. the 13b i have has 6 ports. thats 6 intake and 2 exhaust.
does the motor operate on only 4 intake ports and then the last two (5 and 6) open up at a certain speedto increase top speed?? how can i check to see if the actuators are messed up?? or is it a good idea to just take it apart and clean the 5th and 6th ports????
additional info is appreciated.
thanks everyone.

 

OK I should have told you more.

The 6-port rotary runs 4 intake ports at low engine speeds(<3500 rpm), this keeps higher intake runner velocity which helps with fuel atomization, swirl and dynamic tuning. At high engine speeds (>3500rpm), these ports open, allowing more cross-sectional area for the engine to breathe through and advancing the intake timing slightly.

On the S4 (series 4, 1986-1988) The auxilliary ports were opened by exhaust back pressure starting at about 3500 rpm and fully open at 4,000 to 4,000 rpm.

(That is why I made my comment about the springs.)

You have an S5 (1989-1991) These ports (looking the same) are open by a solenoid with air from the fresh air pump at about 3500 rpm.

All you have to do to test them is to start the car, open the hood, look down at them and rev the engine while sitting in nuetral. The port actuator pistons should retract into the chambers, rotating the port sleeves and allowing the engine more air.

I apologize for not being more clear in my previous post.

 

From what I understand the aux ports don't open up when in neutral, only when in gear.

 

You could be right, I know that they do on my S4, but that is just back pressure, the ECU may not ask them to open unless the car is in gear (which poses a problem for testing them.)

If you don't mind, could you test this really quickly?

Thanks for catching that!

 

Nah its almost midnight here, no turny on car for me.

Search the forum, that should tell you whether they open in neutral or not.

One way I've heard of testing to see if they open is to put some grease on the actuators, take it for a quick spin and then pop the hood, see if the grease spread or not.

 

I should have checked Aaron Cake's site.

http://www.aaroncake.net/RX-7/6porttest.htm

The grease will work every time.

 

thank you guys. quick replies and good info. kinda reminds me of my days on honda-tech when I was running my hatch. (lol, i know, ill never go back to 4bangers)

Rob

 

I topped out at 135 and I have an 86 gxl. Have you changed the total wheel diameter on your car? this would cause the speedo to be off, if the wheel circumferance is off from stock.

 

Come one man, i have 91 NA stock except for the air filter, and i have 17' tires all round and my max speed is 130!

 

mods, close the thread. i figured out what's wrong... it's the driver ) =))

 

Man thanx for posting that link I have been trying to solve what else could be causing my car to bog out at 3800 . I have done everything else like grounding you name it . I am gonna try to do this I am hoping it helps out . I have tried moving the rear actuator and it seems difficult to move the rod . I havent tired the front since I didnt know where to look for this stuff until now . When it hits 3800 if I hold it there it will kick in till about 4200 then go back to bog just kick off jaring you know what I mean .

P.S I have been having a really hard time starting it the last few days it turns over but it just floods out then I have to un-flood it . Then when I go to start it again I have to hold the pedal down to even get it to start and this is after its only been sitting for a few hours it does this . If it sits over night it starts up fine

 

My s4 n/a se topped out at 145mph in 4th going down hill when I was still attending Wyo-Tech.. Thats the fastest I ever went..