I have only done one oil change since i have owned my fd and it is time for a second. When i purchased the car, it had synthetic in it, i had heard if you were running an fd with a catalytic conveter, synthetic was bad because of the higher ash content in the burnt oil used for injection in to the combustion chamber. After hearing this i switched to regular castrol GTX. Now i have removed the cats and i am considering going back to synthetic, any thoughts on the matter?.....

 

No, the latest synthetic oils won't harm catylytic converters. That was over two decades ago when the early synthetics were found to contain too much phosphorous (a high-pressure lubrication agent); ash content has nothing to do with it. This subject has been discussed countless times; do a search and you'll finds tons of threads on it.

 

thanks for the insight, so i will probably stick with synthetic...now which brand and weight are the best to use for daily, slightly spirited driving?

 

All of my rx7 s have used synthetic oil starting in 1981 .The first car , 81, I had for 12 years with no problems . I use synthetics in everything . My 94 has syn motor oil and the oil metering pump sends Amsoil two cycle oil to the chambers .

 

There is no "best oil for daily, slightly spirited driving". Do some of your own research here and decide for yourself.

 

so how would i go about sending the 2 cycle oil to the metering pump, just use a separate resavoir and splice the lines in??

 

Dead link

 

Sorry, don't know what happened there. Try this one.

 

I use a metering pump adapter from PCV technologies and a 3 qt tank that I made to fit between the air box ,innercooler and front brace .The cylinder shape tank I made for Rotorbrain fits where the air pump was .

 

For some reason the search function doesn't hold a result page for too long. You'll have to use the search function to do some research yourself. Here's a couple of threads on the subject, just a slice of probably hundreds:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/going-synthetic-quick-questions-synthetic-guys-411254/

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/regarding-synthetic-oil-debate-98039/

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/10w30-fd-279325/

 

I'm not arguing whether adding a 2-cycle oil tank for your OMP is good or bad. But IMHO, if you've only owned the car a short time, you may want to put it a bit lower on your priorities.
Do the search that KENTO suggested and read. I think the one constant in the debate about oil is that you should change it regularly/often and use a quality filter.