Am I running lean?

[advinnie]

Well today I tried .60 idles but the engine didn’t like that run very rich just of off idle. So went back to the .55’s then I stepped up the mains witch where 1.52’s to 1.60’s and now I’m reading 12.3:1 up to around 2400 rpm then it drops to 11.8:1 and stays there till max so I’m guessing the drop is happening when the mains are kicking in?
If so that’s good news cause the turbo is spooling fast at 1800 rpm and boost is starting to build by 2000rpm and I’m hitting the 5psi mark at the same time the A/F ratio drops from 12.3:1 to 11.8:1. So does this mean I’m ready to attempt 10psi ?

[advinnie]

Buguy I did notice that the hesitation when flooring it did go when I fitted the larger idle jets but I was producing a lot of black smoke

[buguy]

I think those AFR numbers are pretty good. Hit it!

[advinnie]

10 psi here I come

[advinnie]

Just a quick link to the sound track of my bug ( blue thunder)
https://www.youtube.com/watch?v=IftX-gC ... e=youtu.be

[buguy]

Sounds like shes running good!
What are your specs again?

[advinnie]

She’s a stock ish 1600 engine with an engle 100 cam, HD signal springs and stock push rods ( the steel ones done my head )
Carb is a Weber dcoe 40 spec’s
28 vents
160 main
55 idles
180 airs
F11 emulsion tubes
250 needle valve
Boost sensitive fuel pressure regulator set at 4 psi @idle
Turbo is a aireserch turbo (Garrett T3) .40 cold side / .36 hot side
If there’s anything I’ve missed let me know and I will answer it

[buguy]

I like it! Sounds nice and responsive.

[advinnie]

It is very responsive

[advinnie]

Right today I’ve tried going to 10 psi boost but have failed. I’m good up to 8 psi at all rpm’s but once over 8/9 psi boost @ 3700 ish rpm I get detonation
Here’s a photos of my ignition map can any of you see an issue?

[advinnie]

A better photo

[buguy]

So can't you just pull more timing out of it at like 3600 rpm?

[buguy]

And your AFR is still good at those rpm when you try 10psi?

[advinnie]

A/F ratio is leaning off after 6/7psi good call
I’m at 11.8:1 up to 6 psi of boost and if I hold 7 psi boost I’m at 12.5:1, at a constant 8 psi I’m reading 13:1, at 9 psi constant boost in at 13.8:1 and that’s where detonation starts and at 10 psi boost the A/F ratio has leaned out to 14.2:1
I done a 9 psi boost run and soon as detonation started I turned of the engine and fuel pump removed the top of the carb and the bowl was empty. I’m thinking the boost sensitive fuel pressure regulator is either not working/ keeping up or the fuel pump is not producing enough pressure?

[buguy]

Oh! Yeah that's way too lean. I always wondered how people keep those full with such a small fuel bowl and low pressures. Are your lines going to the pump big enough to support the fuel you need?