ZZ42Fast

iTrader: (2)

I use a MSD BTM which reduces timing by (currently) 1 degree per psi of boost. I am using 6e and the fuelling, thanks to Tuned Performance, is perfect. I wondered what folk here did to spark tables? I have max at 37.5 degrees but if anyone could share their table with me that would be fantastic.

It is a 305 tpi with a Blowerworks MAF, powermax 2032 cam and Procharger running 6psi (though will be 10 soon).

Thanks!

Orr89RocZ

iTrader: (20)

Stock 305 heads? Might need to pull more than 1 deg per psi. Wot max timing at 4200+ should be 34 for a naturally aspirated deal. Lv8 of 192-208+ is typical wot na.

With boost i found my 305 abit sensitive. Could have been false knock tho, not sure so sneak up on timing. I would have to open up my old tune file to check timing i used. But i do recall pulling abit more than 6 deg for 6-7 psi base wastegate boost

Cruise areas remain stock plus 1-2 deg

ZZ42Fast

iTrader: (2)

Thanks Orr! Yeah stock heads.

When you say cruise plus 1-2 you mean more timing yes? Would love to see your tables if you have them.

Thanks again.

Orr89RocZ

iTrader: (20)

Mine was speed density based but same principles apply. I smoothed out stock table and basically added 1-2 deg everywhere for my 93 oct tune. Lower load areas in the 1200-2800 rpms range

anesthes

iTrader: (12)

I have some old $6E bins that I ran in the 90s with a blower if that helps.

I never ran a BTM, I always just locked timing in. In the early 2000s I switched to 2 bar MAP.

-- Joe

ZZ42Fast

iTrader: (2)

Hey Joe that would be great- thanks. Mail them to me if you like ukzz4iroc at yahoo dot com

Orr- we get nice 98 octane here so that may help nicely

Orr89RocZ

iTrader: (20)

98 oct will help some on timing in boost.

tequilaboy

Your new MAF provides some advantages that can be exploited to aid in the tuning of ignition timing.

Important ingredients for determining safe ignition timing include boost/load, rpm, afr and air temperature...along with compression ratio, fuel and fuel quality, etc...

Assuming that the MAF is installed downstream of the intercooler(s), the sensor's integrated IAT will give you a good idea of the ambient air temp when off boost and the temperature peak under boost will serve as an indicator of overall blower efficiency and intercooler effectiveness. The cooler the better.

I'd consider a 20° F differential with respect to ambient to be reasonable performance. This can provide a guide as to how much timing needs to be adjusted to compensate for the increased charge temperature compared to running n/a.

Due to the sensor's increased flow capacity, the load range can also be extended so that the spark map and other load dependencies may be tuned to better cover the entire range of engine operation, rather than rely upon the last column to cover everything above 208 load. A 150% range extension works well up to approx. 12 psi.

Along these lines, the PE target AFR can be tuned directly as a function of load instead of rpm, linking load and AFR together.

The IAT can then be used to provide additional protection to compensate spark at high temperature.

So the end result is that we can tune the spark advance to be directly dependent upon the key inputs load, rpm, IAT and AFR over the entire spectrum of operation.

Optimizing the values is the hard part, but that's tuning.

ZZ42Fast

iTrader: (2)

Thanks tequilaboy. Great stuff