Do I need to Tune(VS Ecotec)with lighter F/W

[CRACKER/AI0]

I have modded the 6 bolt F/W with an adaptor plate to fit my 3.8l Ecotec.
VR/VS 8 bolt F/W weighs around 10.9Kg with the bulk of it's MASS at the outer diameter of the F/W.

VN 6 Bolt with the adaptor plate made and bolted to the F/W weighs around 9.2Kg with the bulk of it's MASS in close to the Centre( especially due to the adaptor plate).
So I now will have a much more responsive rev response. (at the cost of loosing some Kinetic energy) Still to finish the job and put the manual gearbox in.
Would have put the box in yesterday but had a bolt break off in the Crank

Will this require changing the tune?
(I'm thinking the Idle may suffer a bit. Especially as I'm loosing 1.7Kg of weight and the different make up of the flywheel itself putting most of it's weight into the centre of the F/W)
Thanks for any help

[Holden202T]

i honestly don't reckon you'll notice the difference but your probably going to have to suck it and see

[CRACKER/AI0]

I hope it does improve it.
I have spent a fair bit of time getting the adaptor plate right.
Shame I didn't get a dyno test done before to see if there is a difference.
(mind you it was an Auto before this anyway) and Cessnock sucks for getting a Dyno test anywhere close by.

Just for reference my car
95' VS Commodore (to be manual ) has;

Modified HiTech extractors into a 2" to 2.5" ypiece to hugh flow cat
and 2.5" genie straight through with no dampener, finished with a twin tip.
Heads modestly ported.
enlarged MAF. (I think to 70mm??)
6 Bolt Flywheel and adaptor(home made) off a 89 Vn V6 series 1 block
Still to come ;
USB COMM board+ NVRAM (In the mail )
25mm Mace manifold spacer
12mm Plenum spacer
69mm TB
2X TC06 enlarged (now 50/70 impeller + air intake enlarged) Turbo's (will sell off the Extractors and make my own headers for the turbo setup)

[charlay86]

The modified MAF sensor alone will require your tune to be adjusted to suit it (the PCM will think that it is getting less air than it actually is, due to the increased cross sectional area, potentially resulting in a lean condition).
The mild porting, modified exhaust system and lightened flywheel will probably mean some changes to things like transient fuelling, might be able to get away with a bit more spark advance in some places too.

[CRACKER/AI0]

The modified MAF sensor alone will require your tune to be adjusted to suit it (the PCM will think that it is getting less air than it actually is, due to the increased cross sectional area, potentially resulting in a lean condition).
The mild porting, modified exhaust system and lightened flywheel will probably mean some changes to things like transient fuelling, might be able to get away with a bit more spark advance in some places too.

I check the MAF out. its opened out to 71mm. When I put it on the car and started it there was a bit of coughing and spluttering for a couple of seconds.
Then the engine cleared and now there's no probs. (except for the fact I have no gearbox in the car yet )

With the auto to manual conversion I had to muck around with getting the flywheel right and took the plugs out.
They do have a perfect burn with a rusty tip. ( I pretty sure the car used to run a bit rich so maybe it's come up good with the bigger MAF??)

Havent had car running with the F/W done. I hope to be finished tomorrow or Sat. I got the brken bolt out of the crank today

[charlay86]

You will also need to adjust the tune for the manual gearbox (or just start with a manual tune and go from there).
If you aren't going to get it tuned right away I would reccomend getting a standard memcal with a manual tune and run the stock MAF sensor, just to be on the safe side until you can tune it properly to suit the larger MAF and other mods.
If you are keen to tune it yourself, you will also want to invest in a wideband O2 sensor & controller.

[Holden202T]

sorry i wasn't meaning you wont notice the difference in the weight of the flywheel i was referring to the tune shouldn't notice the difference.

that said theres too many other mods that would throw the tune out anyways!

[CRACKER/AI0]

You will also need to adjust the tune for the manual gearbox (or just start with a manual tune and go from there).
If you aren't going to get it tuned right away I would reccomend getting a standard memcal with a manual tune and run the stock MAF sensor, just to be on the safe side until you can tune it properly to suit the larger MAF and other mods.
If you are keen to tune it yourself, you will also want to invest in a wideband O2 sensor & controller.

Sorry should add,
With the Auto to manual conversion I am installing a VS manual ECU and using the Auto loom (but changing C5 to D2 for the speed sensor, as well as adding the wire from the speed sensor to D2 so it will end up being the same as a manual wiring loom.
plus disconecting the obsolete wiring from the Trans plug etc, etc.
Hopefully the VS ECU I bought (back before I read up on converting the Auto ECU ) will be working fine.

What's the wideband O2 sensor & controller worth, and where can I pick one up for a reasonable price?
I'm just about to buy the NVRAM from VL400. Already have the USB Comunications board on it's way.

sorry i wasn't meaning you wont notice the difference in the weight of the flywheel i was referring to the tune shouldn't notice the difference.
that said theres too many other mods that would throw the tune out anyways!

No probs Holden202, I figured you meant it that way. Thanks to both you and charlay86 for the input.
Cant wait to get it up and running again. Was speuing when the bolt broke off in the crankshaft.I was nearly finished with what I was doing too.
Luckily it came out without too many headaches.

[CRACKER/AI0]

These are the mods that will apply when starting up.
Modified HiTech extractors into a 2" to 2.5" ypiece to hugh flow cat
and 2.5" genie straight through with no dampener, finished with a twin tip.
Heads modestly ported.
enlarged MAF. (I think to 70mm??) But will put the stocky back on if that's recomended
6 Bolt Flywheel and adaptor(home made) off a 89 Vn V6 series 1 block
SO FAR WILL STILL HAVE 3:08 LSD diff.
Still to come ;
USB COMM board+ NVRAM (In the mail )

The other stuff ie: turbos, Mace spacers, bigger TB, are for later down the track.

Have I just discovered my extreme NOOBness and that I should be calling the ECU a PCM?? (which I do think is called the Power Control Module)
I have a number of ECU's ? PCM's ?? here I have,
1 manual PCM from a 98 VN series 1
2 Auto PCM's from VS ecotec (Once I get with the program will convert one to run in my car with the T5 manual so I can sell off the manual ECU/PCM)
I'm going to go to the shed now and bring them in to take a look at them. (It's learning night tonight) Want to know which is an "808" ,"672" etc.
I'll go back through the beginners guide too.

[yoda69]

PCM - powertrain control module, does both engine & trans
ECM or ECU - engine control module or unit, does engine only
TCM - transmission control unit, does trans only

Gets a little confusing on later models like VT where the same computer is used on both.

Yoda69