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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
Posts: 5,564
As far as I can see, engine is almost stockish except for KKK 7200 and EFI.

My suggestions are following:

1. Find and adjust trigger until 0 deg. in software means 0 deg. in hardware. Check with timing light.

2. Advance timing to 15 deg. and check that timing jumps 15 deg. in hardware (to be sure that trigger wheel software-interpretation is OK).

3. Engine being stockish (no twin-plug, right?), start with initial timing advance slightly below OEM 26 deg. (to safeguard against possible lean condition), disable accelleration enrichment (that assumes you arre doing long pulls in 3:rd or so) and do pulls and mapping of fuel cells until AFR's are rock-solid in 12.8 to 12.4 range. (I prefer 12.8, many have different opinions of AFR's on aircooled cars. It's yours and your tuners call). Devote extra time to make AFR's stay flat between trasition from no-boost to boost. This is the trickiest area to map as VE takes a big jump. Making this work 100% will improve spoolup and driveability, which won't show on peak dyno numbers.

4. Once AFR's are in check start advancing the ignition timing towards OEM and superimpose torque curves after each. Remember that you are tuning for gas being in tank...once tuned, you shouldn't fill it with lower octance brew. You will see torque slightly increasing untill you hit the limit. (Always check your AFR's during this). Limit will be either when torque starts dropping or engine starts to ping. As this engine is less forgivable of pining, I suggest playing it safe and increasing the timing to roughly OEM value and not going the whole length of finding out where it pings to save piston rings. As far as I know, gas in Oz is not always good and weather is hot. When all is done, you should be making around 330-340hp and will have total advance around 26-28 deg.

5. (This is a fine part). Ask yourself what is more important: torque off-boost or quick boost? There are tricks you can play with ignition to achieve quicker spoolup. Of course, there are always drawbacks. In case of track car that will spend most of it's time revving above 3000 RPM and where getting out of boost hole is important, it might be usable to actually drop the timing just before boost treshold in order to spool turbo quicker. This will make car consume more fuel in steady-state (like cruising on highway) but it will give you slightly more response once you nail it. Re-check AFR's after doing this and make necessary adjustments as AFR's might change.

6. Re-enable accelleration enrichment and play around with different values until fast prod of thottle in low gears doesn't make engine bog down. This is trial-and-error stuff.

7. Do a dyno pull and brag on PP

I'm sure you'll get to bottom with this, build sheet sounds solid. It's just a software glich
Thank you for your time,
Old 11-14-2007, 06:22 AM
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