redeagle

Problem is that AFR is ~13.2 under WOT and fuel pressure gauge shows only 70PSI(after closing needle valve shut, before only 60 and dropping) first and then drops ~65PSI which is way less than described in manual. Under part throttle it shows 11.6 to 12.5
Idle and vacuum pressures are as described in BEGI manual and when line is closed shut it shows 85+PSI on idle
Question is what to do next?
Replace injectors to toyota 315cc(as i have them) and tune or
Replace fuel pump ( I could get 190LPH or 255LPH for good price)

gospeed81

iTrader: (51)

Both.

budget racer

iTrader: (1)

you may not be able to idle injectors that large. people typically move to 1.8 injectors to ensure adequate fueling while in boost. yes, a stronger fuel pump is a good idea too.

redeagle

Thank you for replies. Unfortunately it is almost impossible to get 1.8 injectors here (unless you get them from US) so i just need to give a shot on 315cc first.

Savington

iTrader: (31)

Lots of folks used the 305cc Supra injectors back in the day. The idle with 315s may not be perfect, but it should be more than doable.

redeagle

I'll give them a try then.
When i searched web for injector codes i found following info on toyota 315cc ones:
http://www.witchhunter.com/flowdatapix/d2325074080.jpg
and according to same website supra ones are actually stronger (took the part code from Miata Turbo Wiki page)
http://www.witchhunter.com/flowdatapix/d2325070080.jpg

mekaw

iTrader: (1)

https://www.miataturbo.net/useful-saved-posts-8/diy-faq-all-your-answers-one-big-post-10821/

this thread has good info on everything and answers to your injector question!

redeagle

tnx mekaw, i have allready readed that post as well i'm regualr visitor to Miata Turbo Wiki page.

redeagle

Success after installing toyota 315cc injectors.
Once injectors were in place, car started right away (AFR ~11 on idle).
Tuned a bit using idle mixture screw on AFM and got idle AFR back to ~14.7
Now under boost AFR is ~10.8-11.1 ( need more tune on airfield as on road it's bit difficult). Also capped BKR7E-11 plugs to 0.8mm instead 1.1mm

190LPH pump is on order.

mekaw

iTrader: (1)

I think most people recommend bkr7e and gapped to .030

mekaw

iTrader: (1)

didn't your car run filthy rich just cruising? before you hit the boost?

I remember when i put on supra injectors well 305cc without management and did what you did, it ran fine underboost but for normal cruising it was running relatively around 11ish for afr.

redeagle

That's the interesting part, on cruise AFR is like it was before ~14.7 99% of the time, only sometimes i see ~12.2 for a short time.