can someone tell me how to tell the diffrence between stock 550cc and 850cc injectors? i want to upgrade my primaries to 850's, but i'm not sure if the previous owner has already done this. is there an easy way to tell before i pull off the intake and change them anyway?
thanx

 

I believe the 550's are purple tops and the 850's are red tops.
They are not easily swappable with each other due to different bottom design.


-Ted

 

ok, so what do i need to do to get the 850s into the primary location? do i need a new rail or jusyt modify the old one?

What if i wanted to put some RC 720ccs that I have laying arround into the primarys?

Thanx

 

R..., you can use the stock 850's in the primary stock location, they will fit and will work with no problems, been there done that.

 

I thought the 850cc/550cc injectors were physically different in size?

 

So the FD's have the same physical size primary and secondary? My cosmo engine has side fed injectors in the primary and the regular top feed in the secondary. Hmmm...

 

The 550's are slightly longer than the 850's on the bottom end of the injector, but since the top half of the cavity by where the injector seals, and gets fuel from, is the same you can use the 850's in the stock 550's location with no problems as long as you have the fuel management to control it.

 

Apexi Afc to control the larger injectors?

Thanks for any info.....