a few questions

This will be cross-posted, so i appolgize to anyone who reads it more<br>than once..<br><br>I have a 1991 Brg Special edition miata with the 1.6 ltr engine (and the<br>short crank) she's got 90k plus miles on it.. no modifications yet..<br><br>I've got three questions.<br><br>1) Its started using up a little oil... i dont think the rings are gone<br>yet.. ive autocrossed it only a few times.. the engine has never been<br>rebuilt.. is this normal? what can i do to stop it and maintain<br>performance.. and how much would an engine rebuild be? Btw, i'd heard<br>something about possibly going with a different wght oil.. suggestions?<br>been running 10w 30<br><br>2) Im about to make the first modification on this car.. i autocross it<br>in scca stock, as i dont have enough money to do all the needed mods to<br>put it in the next cat. up and stay competitive.. i plan on doing a<br>cat-back exhaust.. i commute with this car occasionally.. im not really<br>looking for maximum volume.. just performance.. looks like NOPI has a<br>great deal on the Jackson Racing Cat-back right now.. any suggestions?<br>because its a simple system a friend suggested a free flowing strait<br>pipe.. he's nuts.. any SANE suggestions?<br><br>3) its about time for a tranny oil change.. should i go to redline synth<br>fluid?<br><br>Thanks.. -TJ

I'm not an oil geek so I don't know about that. I have a Thermal exhaust on my Miata and love it. It is not raspy or buzzy at all. the car sounds like it has a V6 in it, it has a deeper sound. There was a SOP difference also, probably good for 3-5 HP. Very noticable in a Miata. I bought my Thermal from M-Road/Mazda South, ask for Dan Pedroza, he's the man!

well for starters how much oil does it use per oil change? if the rings are ok then it could be your valve seals are starting to dry up and leak. another source could be an oil leak. those are my two ideas for the oil leak. and as for the engine rebuild if it has good compression then you may be able to just rip the motor apart install new bearings,rings,and gaskets wash it and give it a dingle ball hone, and a valve job and be good to go. if you did that yourself the total cost would probobally be about $100-150 but if the compression is getting lower and you have ridges across the tops of the cylenders then its time for a full rebuild and that could be anywhere from 500 to 1000. remember most of that cost is ripping the motor apart if you do that yourself then its just the machine work which still can be expensive but not nearly as expensive as paying $80 per hour to have a tech do it.