Am I running lean?

With Turbo and Super charging you can create massive horsepower with vw motors.

Moderator: seabeebuggy

Post Reply
advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Fri Feb 16, 2018 10:31 am

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
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Fri Feb 16, 2018 11:17 am

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

User avatar
buguy
Posts: 1588
Joined: Wed Jan 26, 2005 11:53 pm
Location: Port Orange, FL

Re: Am I running lean?

Post by buguy » Fri Feb 16, 2018 12:34 pm

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

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Fri Feb 16, 2018 2:30 pm

10 psi here I come 😁
You do not have the required permissions to view the files attached to this post.

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Fri Feb 16, 2018 3:02 pm

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

User avatar
buguy
Posts: 1588
Joined: Wed Jan 26, 2005 11:53 pm
Location: Port Orange, FL

Re: Am I running lean?

Post by buguy » Fri Feb 16, 2018 7:34 pm

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

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Sat Feb 17, 2018 3:53 am

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 😁

User avatar
buguy
Posts: 1588
Joined: Wed Jan 26, 2005 11:53 pm
Location: Port Orange, FL

Re: Am I running lean?

Post by buguy » Sat Feb 17, 2018 8:53 am

I like it! Sounds nice and responsive.

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Sat Feb 17, 2018 9:27 am

It is very responsive 😁

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Sat Feb 17, 2018 9:39 am

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?
You do not have the required permissions to view the files attached to this post.

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Sat Feb 17, 2018 9:41 am

A better photo
You do not have the required permissions to view the files attached to this post.

User avatar
buguy
Posts: 1588
Joined: Wed Jan 26, 2005 11:53 pm
Location: Port Orange, FL

Re: Am I running lean?

Post by buguy » Sat Feb 17, 2018 10:02 am

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

User avatar
buguy
Posts: 1588
Joined: Wed Jan 26, 2005 11:53 pm
Location: Port Orange, FL

Re: Am I running lean?

Post by buguy » Sat Feb 17, 2018 10:15 am

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

advinnie
Posts: 667
Joined: Mon Jun 10, 2013 6:54 am
Location: Oxfordshire

Re: Am I running lean?

Post by advinnie » Sat Feb 17, 2018 11:29 am

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?

User avatar
buguy
Posts: 1588
Joined: Wed Jan 26, 2005 11:53 pm
Location: Port Orange, FL

Re: Am I running lean?

Post by buguy » Sat Feb 17, 2018 12:07 pm

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?

Post Reply