3.5 Advance amount.

[discomark10]

Hi guys,

Just installing a MJ setup on my 3.5 efi.

Been reading about the advance map table and that a smaller CU can run more advance, my question is what the max on a 3.5?

And also does it matter what the compression ratio is?

Cheers Mark

[Quagmire]

Here's something I sent to another forum member a little while ago - might help get you started...

I can't find the charger for the laptop my latest map is on, but If you go to here:

http://www.classicro...16625&start=120

And scroll some way down you will get to a screenshot of the map I am running in my Rover P6. This is a 3.5, running 9.25:1 compression and using later 10 bolt heads. It goes very well indeed!

If your 3.5 is a similar compression then you should be ok, if its lower (8.13) then you may need to up the advance a little bit- how much I have no idea! Just keep your ears peeled for pinging, and if in doubt, stop.

I built the map using the info from here:

http://www.rover-cla...e/enginev8.html

and wrote about it a bit on here (I had questions about ported vs manifold vacuum):

http://www.v8forum.c...e5a6c11ac7b92a9

Hope this helps,

Have fun!

Jamie

[discomark10]

Jamie your a gent, thanks for all the great links.

Mine is indeed a 8:5.1.

So from my understanding you can run more advance with a higher RON fuel as it is more resistant to knock (pre-detination)

According to Nige's post the max advance on a 3.5 is 36.

http://forums.lr4x4.com/index.php?showtopic=15317&view=findpost&p=239333
3.5s - Max of 36 degrees at around 3100-3200 .........(if you have a 'sleeved 3.5' with reduced CC (ie 3400) then 38 Degrees at 3200)
3.9s Maximum of 34 degrees 3750-3850
4.2s to 4.5s max 31 degrees @ 3900-4000
4.6s and bigger Max 28 @ 3750-4000

According to this table below and presuming its scales up the rev range with a low comp I can run more advance on the same RON fuel on a low comp motor.

<table 712"="" border="1" style="margin: auto; padding: 0px; color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-size: medium;">

At 600 rpm Compression Timing 10.5:1 6 degrees BTDC for use with fuel of 100 minimum research octane number. TDC for use with fuel of 96 to 99 minimum reasearch octance number 9.25:1 6 degrees BTDC for use with fuel of 96 minimum research octane number 8.5:1 6 degrees BTDC for use with fuel of 90 minimum research octane number

for a 3.5 at max advance (36deg)

9.25:1 on 96 is 0.375 deg per RON

8.5:1 on 90 is 0.4 deg RON

so 95 (regular unleaded) is 38 deg
97 is 38.8 deg

So does this sound right?

Cheers Mark

[Hybrid_From_Hell]

^^ Spot on !

[discomark10]

^^ Spot on !

Cheers

Here's something I sent to another forum member a little while ago - might help get you started...

I can't find the charger for the laptop my latest map is on, but If you go to here:

http://www.classicro...16625&start=120

And scroll some way down you will get to a screenshot of the map I am running in my Rover P6. This is a 3.5, running 9.25:1 compression and using later 10 bolt heads. It goes very well indeed!

If your 3.5 is a similar compression then you should be ok, if its lower (8.13) then you may need to up the advance a little bit- how much I have no idea! Just keep your ears peeled for pinging, and if in doubt, stop.

I built the map using the info from here:

http://www.rover-cla...e/enginev8.html

and wrote about it a bit on here (I had questions about ported vs manifold vacuum):

http://www.v8forum.c...e5a6c11ac7b92a9

Hope this helps,

Have fun!

Jamie

Having a look though the rest of the links and looking at your map, how on earth are you running 46 deg with no knock?

[Quagmire]

That 46 degrees is only ever seen with the throttle fully closed at high revs - in these situations you can have a lot more advance that at WOT. At WOT it is only getting something like 30 I think? (photobucket is blocked on the vessel so cant get to or see any of my own pics). So far it has done about 3000miles with this setup and no issues at all, well, none engine related anyway

No sign of pinging either, but to be honest without some form of det cans I wouldn't expect to hear anything at that kind of rpm in the P6 as it is very well sound proofed compared to a landrover... You should be able to hear a lot better.

I arrived at that figure when I built the map, which basically meant taking the quoted mech adv figures for my dizzy, and using them to populate the 100kPa row. I then converted the inHg quoted for vac advance to kPa and worked those in vertically.

If you are worried about adding that much just back it off a little. If you use the factory figures for advance at WOT you cant go far wrong, as they should be a little conservative.

[discomark10]

That 46 degrees is only ever seen with the throttle fully closed at high revs - in these situations you can have a lot more advance that at WOT. At WOT it is only getting something like 30 I think? (photobucket is blocked on the vessel so cant get to or see any of my own pics). So far it has done about 3000miles with this setup and no issues at all, well, none engine related anyway

No sign of pinging either, but to be honest without some form of det cans I wouldn't expect to hear anything at that kind of rpm in the P6 as it is very well sound proofed compared to a landrover... You should be able to hear a lot better.

I arrived at that figure when I built the map, which basically meant taking the quoted mech adv figures for my dizzy, and using them to populate the 100kPa row. I then converted the inHg quoted for vac advance to kPa and worked those in vertically.

If you are worried about adding that much just back it off a little. If you use the factory figures for advance at WOT you cant go far wrong, as they should be a little conservative.

Yea that makes sense, Its all new to me so having to get my head around it.

I'm tempted to setup a knock sensor, even if its just to a pair of headphones to get it setup.

Something like this http://www.dwjenkins.plus.com/knock-detection.htm

[missingsid]

Here's something I sent to another forum member a little while ago - might help get you started...

I can't find the charger for the laptop my latest map is on, but If you go to here:

http://www.classicro...16625&start=120

And scroll some way down you will get to a screenshot of the map I am running in my Rover P6. This is a 3.5, running 9.25:1 compression and using later 10 bolt heads. It goes very well indeed!

If your 3.5 is a similar compression then you should be ok, if its lower (8.13) then you may need to up the advance a little bit- how much I have no idea! Just keep your ears peeled for pinging, and if in doubt, stop.

I built the map using the info from here:

http://www.rover-cla...e/enginev8.html

and wrote about it a bit on here (I had questions about ported vs manifold vacuum):

http://www.v8forum.c...e5a6c11ac7b92a9

Hope this helps,

Have fun!

Jamie

Twas I and it is running and sounding great.

I did not comment earier as I wanted to let first hand info arrive for this request.

Marc