sparkplug reading on turbo 4age

[turboae92]

Hi I have turbo ae92 with high compression setup and would like to know more info on how's the engine is running.

[yoshimitsuspeed]

They look pretty good to me. Maybe a little on the light side. If you want to learn how to read spark plugs there is a lot of good info that can be found on Google. It is a very archaic method of tuning at this point in time. It would be like trying to win your local autocross running on wagon wheels.
If you really want to tune your car get a wideband. This is a good first step. Knock monitoring and pyrometer are very good next steps to understanding what's going on inside your motor.

[turboae92]

Thanks yoshi I also think I'm a bit lean but not far off.i do have a wideband at wot it's about 11.3 afr.

[yoshimitsuspeed]

Why would you need to read plugs if you have a wideband? 11.3 is plenty rich.
Of course you would need to cut the motor right then to read the plugs from that range anyway. You are probably seeing the effects of idle/cruise AFRs on the plugs.

What heat range are you running?
How much boost?
What compression?
What timing?
Aftermarket engine management?

[turboae92]

Ngk cooper heat range 7 with .26 gap
12 psi on 50 trim turbonetics turbo
10.1 compression
Ms1 v3.0
Idle 15 degrees , cruise about 36 and wot about 16 degrees
93 octane

[yoshimitsuspeed]

After reading this article and looking over some other 4AGTE timing maps I'm thinking you may just need a colder plug.
http://www.dragstuff.com/techarticles/r ... plugs.html

That and another article say to focus more on the porcelain for AFRs. What I can see of yours doesn't look too bad. On top of that your wideband will tell you more than the plugs ever will.
Now ideally you would tune timing for MBT or detonation depending on which came first across the band then adjust your heat range. Your map doesn't sound too aggressive though so as long as you aren't getting any detonation I would lean towards trying one heat range colder.

[turboae92]

That's a great article thanks yoshi , two weeks back before this plugs I had same ngk cooper but heat range 8 and we're nasty dark from unburned fuel.i also had detonation so I back down on the timing 3-4 degrees total.So far this the best plugs I've tried and no audible detonation. Hey yoshi I been looking at ur website for a while now and I like alot of things u make , I wondering how close ur turbo manifold gets to the distributor because my ebay one likes toasting my distributor electronic and caps.

[yoshimitsuspeed]

That's a great article thanks yoshi , two weeks back before this plugs I had same ngk cooper but heat range 8 and we're nasty dark from unburned fuel.i also had detonation so I back down on the timing 3-4 degrees total.So far this the best plugs I've tried and no audible detonation. Hey yoshi I been looking at ur website for a while now and I like alot of things u make , I wondering how close ur turbo manifold gets to the distributor because my ebay one likes toasting my distributor electronic and caps.

Sounds like you are in a pretty good range then. Looks like they might be on the hot side but if the next step colder doesn't work and if you aren't getting detonation it sounds like you may be right about right.

I can take some measurements.
Do you have the heat shield like the AW11 dizzy?

[turboae92]

Yes I'm running aw11 distributor without the shield and also I had to crush the cylinder 1 pipe just bit for more room then I wrapped it .

[yoshimitsuspeed]

Wow, can you get some pics?

Do you think a better heat shield would help? I have been thinking about making one.

[turboae92]

Will take a pict tomorrow and no space for heat shield

[turboae92]

[yoshimitsuspeed]

That looks weird. I don't remember mine looking nearly that close. I'll have to throw the mani and a dizzy back on my mockup motor to see how it looks. Is there really only a few mm between the dizzy and runner at that narrowest spot or is that an optical illusion?

[turboae92]

Yes is that close.

[yoshimitsuspeed]

I put my mani and dizzy on a head today. It looks like there is probably about 10mm at the closest point. The #2 runner looks to be a lot further away than yours which may help.
I took pics today but haven't uploaded them yet.