Thread: Dyno Chart
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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
I agree with Brian and Jim. You do not need the boost delay function at that hp level and your WUR settings are not right in most all respects it seems.

As to AFR goals, max acceleration (pre boost) is at about 13.2/1. Safe on boost AFR is probably about 11.5/1 for CIS. You make more HP in the low 12's on boost but it is safer to shoot for around 11.5/1 at TQ peak with CIS as it is not as accurate as EFI. On a street car you can let your AFR's creep up some after HP peak but to no more than about 12.5/1 at red line if needed.

Idle and off idle AFR is adjusted at the fuel distributor.

Cruse AFR is adjusted leaner by increasing hot control pressure.

On boost AFR is adjusted leaner by increasing enriched / on boost control pressure.

All adjustments have to be ballanced against each other and changing one can change the other.

Start with setting your AFR or CO at idle. For max acceleration use your wide band and shoot for about 13.2/1 of idle untill boost enrichment is triggered. You may end up running fat at idle if you do this or you can just set it at 14/1 for better economy.

Your AFR's climb quickly with acceleration even without boost enrichment!

It almost looks like you have a HF fuel distribuitor or your system pressure has been jacked to get you more fuel but is probably just the WUR settings. Your base hot control pressure seems to low. If you increase it you will not go as fat as quickly. You want to stay near 13/1 untill you hit about 5psi boost and the boost enrichment is triggered.

This will also effect your cruse AFR. What is you AFR on cruse? I suspect you are probably fat there looking at your AFR curve.

I might shoot for about 14/1 at cruse as a comprimize between accelleration and milage. For better milage you could go for around 14.7/1. For better performance you might use your wide band and look for low 13's with first throtle input off cruse.

Boost enrichment:

As noted, you are way to fat on boost. Increase your on boost / enriched control pressure setting and shoot for the mid 11's at TQ peak and try to stay in the hight 11's from about 4500rpm thru about 6250rpm.


Full boost:
You are reaching full boost at about 3600 to 3900rpm depending on your boost level. This seems late even for C2 cams and stock heat exchangers for a car with a good muffler and HF turbo. Getting your AFR's in a better range should help some.

This and your rich AFR's almost make it look like you could have a boost leak but I am not saying you do.

After the AFR's are all near there ideals, you might look into dialing in your timing curve.

More advance off idle might improve throtle response and reduce spool time. However, you need to be carfull not to advance timing when on boost past about -20 deg unless you have good info that your build and fuel can handle it safely.

Not an expert, just what I belive so far.
Old 05-07-2010, 07:47 AM
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