yeah i wonder.... i just went and port matched some t2 manifolds wen i did a 6 port turbo setup...

 

Same here....

 

The 3500 rpm hesitation is usually caused by a ground issue...



The following is from ICEMARK from the RX7 Club:

I have this hesitation whenever I accelerate right around 3500-4000 RPM

The dreaded 3800 RPM hesitation is cause 90% of the time by poor ground connections between the engine, the battery, and the car. Clean or replace all the under hood ground connections. On 86 model year cars , replacing/regrounding the pressure sensor's ground wire has helped (do not re-ground a 87 or later model year). If there is still a problem after that, look at cleaning the fuel injectors and (on a N/A) that your 5th/6th ports are operating correctly.



Hope this helps...

 

cant believe no one thought of this, the 3,800 hesitation

 

I'd say the 3800RPM grounding issue is very likely; don't rule out a clogged cat as well (If you running one).

 

Sorry i haven't replied to you guys a bit sooner. The car hasn't got a cat so i think the problem is likely to be either earths or fuel injectors. Has anyone ever used these fuel injector/engine cleaners that you pour in the fuel tank and do they have any effect. I am tempted to try that before removing the injectors but i don't want to course any damage to the engine.



Cheers to the members who have helped out, you guys are legends and i can't wait to have the old rx running at full power as i'v never experienced this yet.





When i get some better pics of the LIM i will post them as well.

 

Fix your grounds first man. Pick up a generic grounding kit and go to town with FAQ in hand. Chances are this is your problem.



Also... Injector cleaners work SOME of the time, but for the most part, they are worth their weight in tapeworms. Just run some MMO (Marvel Mystery Oil) in your gas from now on. Its a pretty gentle solvent that won't ruin anything. Over some time it might fix your problem (if its not grounding).



Ultimately, if grounding doesn't help, send your injectors in to get ultrasonically cleaned and flow tested. Thats where you will notice a difference.

 

The cleaners aren't going to hurt anything but, they're more for preventative maintenance than harcore cleaning.



What you might try though is do a double does of the cleaner. If the bottle treats a full tank of gas, do 2 bottles. I did thiss once and it cleaned a butt load of carbon out. So much so, it clogged my cats!

 

I use a product called SeaFoam to clean injectors. Good stuff.

 

Did this form of 6th port actuation make any more hp or torque than the rotating sleeves did? It seems like a cleaner, more consistant method of controlling the extra ports, and would have the benefits that you would get from running the sleeve inserts. Whats the reason that europe got a different form of actuation?