VT GTS Memcal

[yoda69]

I'm not sure what the random $6D is doing at location $13374.
The changes at $4C02-7 are for rev limit (fuel cutoff), have been raised from 5600rpm ($E0) cut and resume at 5500rpm ($DC) to 6300rpm ($FC) cut and 6200rpm ($F8) resume.
What's more amusing, is that all the spark changes have been made to the LOWOCTAIN tables and no changes to the main spark tables.
Also the injector rate constants have all been significantly lowered, I'd hazard a guess the vehicle has been fitted with larger injectors.

yoda69

[benk]

I opened it in an earlier TP4 on my other computer, have tried it in TP5 and has opened and read ok
I will have a play with it tonight and see what has been changed from the original
From the spec's of the cam I would say it is a stage 3 or 4. Will only just idle at 850rpm
We are going to chuck it on the dyno tomorrow and see exactly what it is doing.

[benk]

I'm not sure what the random $6D is doing at location $13374.
The changes at $4C02-7 are for rev limit (fuel cutoff), have been raised from 5600rpm ($E0) cut and resume at 5500rpm ($DC) to 6300rpm ($FC) cut and 6200rpm ($F8) resume.
What's more amusing, is that all the spark changes have been made to the LOWOCTAIN tables and no changes to the main spark tables.
Also the injector rate constants have all been significantly lowered, I'd hazard a guess the vehicle has been fitted with larger injectors.

yoda69

Yes, it has bigger injectors fitted as well as a lot of work done to the engine so I would say that the rev limit has been changed for the cam.
I jus relised that I haven't done any tunning with engines with maf sensors on them before and can't realy make much sense of the maps. Looks like I will have to do some study

[yoda69]

From what you've said about the engine try the following to start with.
Start with the base CFZF tune, the one in it has too many issues.
Copy over the idle speed settings from the modified bin as a starting point.
Adjust "Base Injector Rate" to match the injectors. (as a guide, bluetops (24lb)should be 325msec/gram. SC V6 (36lb) are 214msec/gram, standard V8 are about 362msec/gram. ie.The bigger the injector the less time required to squirt 1 gram of fuel.
I would adjust the idle spark up to somewhere in the mid 20's when warm, just see what the engine likes.
Then work on the injector rate to fine tune fuelling and main spark settings.
Once the base is sorted, then start looking at Open Loop AFR and PE settings.

Good Luck,
yoda69

[benk]

Looks like I will have to order a NVRAM to fit

[benk]

Just a quick question on the maps for the maf sensor
I take it that the "mgc" is the maf sensor and the higher the number the more the air flow. Is this correct?
Also trying to work out how the injector rate table works (injector rate constant V mg/cy V RPM) Is this the one you do the fine tuning on to get the afr correct?

[yoda69]

The MAF has an output in HZ and relates back to grams/second going through it. The higher the number the more air.
The mgc is milligrams per cylinder, this takes the MAF value, RPM, Engine Capacity and number of cylinders and works out how much air is going in to each cylinder. It is similar to MAP, low mgc is vacuum, and high mgc is load. ie. if at 2000 rpm the MAF has a value of 100 and an mgc of 500, then at 4000rpm the the MAF could read 200, but the mgc would still be 500. The mgc is independent of time (rpm) and is only related to how much air is in the cylinder at that aprticular moment.
The injector rate constant is a multiplier used at a given RPM and load to adjust the Pulse width of the injector, a number under one reduces the time and one above 1 increases the time. If your injector rate and MAF table are correct, most values in this table should lie between about 0.8 and 1.2 based on the factory bins, that was part of the reason I thought the vehicle had bigger injectors as the values were all under one and down to about 0.57 I think.

yoda69

[benk]

I noticed that the injector size is the same on the standard tune as this modified tune. I will check today but am sure that it has got bigger injectors fitted

[benk]

it has 40lb injectors fitted so I worked out that the new base injector rate should be 198
BTW these are the specs on whats been done to to the motor

COME Pro series solid roller cam CS3R-411 grind
COME Twin throttle intake
VN Style Race heads
Port matched and flow tested
Kieth Black 10.4:1 Flat tops with sealed power rings
5.7 chev rods
355 Harrop Crank
4bolt mains

If you have any ideas with these specs if I should change anything else in the standard tune before I load it in
BTW did a dyno run on the tune that was in the car and theAFR was all over the place and wouldn't rev above 4000rpm as the AFR fell below 10

[Holden202T]

lol sounds like a good tune then ..... sounds like it should be a pretty reasonable motor once its dialled in!