fine tuning fine points.........(little help)

[magnus_heydoc]

Ok so here's the set-up:

61mm turbo
lex/550s
walboro FP & AFPR (30psi with vac at idle)
WB
safc
running 1.2 bar on 100 octane fuel.
newer motor with forged internals


I'm trying to get to the low 11s A/F ratio and it's still pig rich (low 10s), in fact if I keep it on the floor it moves its way into the 9s.
Before I get flamed here I tried searching and didn't seem to find what I was looking for.
I had a couple thoughts and maybe the community can direct me.

1) Should I lower FP some as the lex/550 setup seems to be wicked rich inherently? Maybe this will get me a bit leaner?

2) I hesitated to reduce the fuel with the safc any further as I've read that reducing fuel at the various rpm levels by more than 15% would cause the ECU to alter timing (making it richer still?)

3) Screw the aftermarket screw (from reg reimer) in all the way in the lex AF body?

Any guidance would be cool by the usual 'mavens'
I'd rather not blow up another motor
thanks
Aaron

---------- Post added at 08:14 AM ---------- Previous post was at 08:04 AM ----------

while I'm at it here can anyone comment on how much boost is generally safe with 100 octane fuel?
20psi?

 

[7M-KDL]

if it is rich i believe you want to back that screw all the way out(as it lets in more air to help lean out) i am having similar issues only im running 660s/lex and a boss turbo at only 5lbs but i get afrs in the 10s at cruise and my base is only at ~34psi. as for the boost thing, from what ive heard 18-19 is the most boost you want to run on pump gas.

i should also tell you that i know for a fact that i have at least one boost leak which causes some of the dipping into the 9s at WOT. have you checked for leaks?

 

[magnus_heydoc]

Thanks for the reply.
I'll definitely check hard for leaks.

I've read diferent things about that screw. Some seem to suggest it's unmetered air and it would make me leaner screwed all the way out and others suggest it blocks the electronic 'dink' from air and then influences the ECU to make it leaner when it's all the way in. I don't know what to believe. Someone that knows what's going on should comment on what really happens.

At cruise I'm 14.5. Trouble is at WOT, the longer I hold it the richer it gets.

I have a Boss turbo as well 61mm, stage 5 (whatever the hell that means!)

 

[isnms]

More air = leaner
Backing the screw out = more air = leaner

Read up here:
• Lexus/Riemer Air/Fuel Upgrade For 7MGTE
• Tech Notes on Lexus V8 air meter and Lucas 550cc injector upgrade

 

[magnus_heydoc]

I should mention I'm running 100 octane 'low lead' Avgas. (turbo prop fuel) for whatever that's worth.

---------- Post added at 02:58 PM ---------- Previous post was at 02:58 PM ----------

I must have a boost leak. I'll look into it.

 

[87supradude]

get rid of the boost leaks, back out the screw, drop the fuel tuner to 0. check your vf. let that settle out and then you can work the fuel presure to get you even closer. get the timing right and then you can work back and forth with the piggy back and your vf. good luck, I fought mine forever and decided to go maftpro to set target afr's.

 

[magnus_heydoc]

thanks for the reply folks.

my timing is correct as far as the tsrm is concerned.

When I check the vf what is my target?

 

[isnms]

There is a link in my sig