So my RX8 starts up fine cold and if I let it get to operating temp. in my driveway and shut if off it'll start right back up. If I go for a long drive and then try starting it up it won't start I usually have to wait 20 minutes before I can start it. There is no power loss and the engine runs very smooth its just the hot starting that is hard.

I have also noticed that my starter cranks very very slowly for hot starts and it is the mazda 2.0kw starter any ideas why?

new battery
bhr ignition kit
28,000km on new engine

 

Slow cranking = not good

Possibly bad/loose battery cable connections since it was recently changed, maybe not if the same condition existed prior.
Possibly bad/worn starter motor brushes, how old is the starter?

Carbon/sticky seals do not affect cranking speed. Hot vs cold motor affects compression (lower hot), but again does not affect cranking speed, just that lower compression needs faster cranking speed to start. Recommend the 2009+ starter if that is the issue and you can afford it, fastest one made; powerful motor and larger/faster nose gear. When it comes to starting a hot rotary engine a fast starter makes all the difference.

Could be other things too though; maybe fuel pump is on its way out which usually shows itself when hot. Ultimately you need to resolve the cranking speed issue though.


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Starter is about a month old and is the new 2009+ 2.0kw starter

 

Look at the starter wiring...something is giving you a bad connection when warm. Remember that the ground to the engine is very important to check...all of the current to the starter has to have someplace to go

Like Team said...the starter speed should be the same hot or cold