[GA/\/\/\/\A_CT]

For OTS tunes, is it generally safer to use a 91 tune? For example, if I am concerned about knocking/detonation would using pump 93 gas on a 91 octane tune mitigate that sort of risk?

[xnick101]

You're overthinking it. Just run the 93 tune with 93.

[mike@x-ph.com]

Sure, the less boost, the more safe the map is. Stock is safer than both options. You can also run less boost than stock, and it's a safer map.

If you run the recommended maps, you are safe. The likelihood of anything going wrong is almost non-existent, as proven by hundreds of thousands of users and over ten years of history.

If you don't feel safe with these numbers, enjoy your car stock.

[GA/\/\/\/\A_CT]

Thanks guys

[WernerM340IX]

Originally Posted by mike@x-ph.com

Sure, the less boost, the more safe the map is. Stock is safer than both options. You can also run less boost than stock, and it's a safer map.

If you run the recommended maps, you are safe. The likelihood of anything going wrong is almost non-existent, as proven by hundreds of thousands of users and over ten years of history.

If you don't feel safe with these numbers, enjoy your car stock.

Are we talking about the JB4 here?

[cyam]

Originally Posted by GA/\/\/\/\A_CT

For OTS tunes, is it generally safer to use a 91 tune? For example, if I am concerned about knocking/detonation would using pump 93 gas on a 91 octane tune mitigate that sort of risk?

Absolutely! That's what I do because our fuel quality is crap (Australia)

With this engine, if you reach the limit of the fuel, you won't get detonation, you'll get pulled timing and boost. Which you don't want. If that is happening then run 91 tune with 93 gas.

Use a monitoring tool (I have MHD) to test and see what is ideal in your situation. Start with 93 tune on 93 gas and do some test runs. If no pulled timing or boost, then you are good, if you are then drop to a 91 tune with 93 gas.

[mike@x-ph.com]

Originally Posted by WernerM340IX

Are we talking about the JB4 here?

We are talking about any proven tune, including the Jb4. Run the recommended maps for your fuel and mods and you have no reason to worry about reliability.

[cyam]

Originally Posted by GA/\/\/\/\A_CT

For OTS tunes, is it generally safer to use a 91 tune? For example, if I am concerned about knocking/detonation would using pump 93 gas on a 91 octane tune mitigate that sort of risk?

I did some testing this weekend. I run MHD Stage 2 with a DP.

Running 98RON (93 octane) fuel and using MHD Stage 2 95 RON (91 oct) map and I get a max of 3 degrees pull back in timing.

Using the same 98 RON (93 oct) fuel and MHD's Stage 2 98RON (93 oct) map I get a max of 7 degrees pulled timing.

So even on the 95 map with 98 fuel I am getting pulled timing. Although a few degrees is acceptable, but not preferable. But the 98 map with 98 fuel - just no way, I can't run that map here in Australia.

The fuel quality in Australia is very bad. MHD saw my logs and said its the fuel.

So I run the 95RON map and put 98RON fuel.

So yes sometimes running a lower map than your fuel IS necessary. But you have to test and see what you can get away with.

[GA/\/\/\/\A_CT]

Thanks. How did you get the data on timing?

[cyam]

Originally Posted by GA/\/\/\/\A_CT

Thanks. How did you get the data on timing?

MHD has monitoring software so you can pull logs and analyze the data.

I would test by logging acceleration runs. Flooring it from 2nd gear through all of third and fourth and into 5th then look at the logs. A solid WOT through all of 4th gear is the ideal place to look at timing. It logs timing corrections per cylinder. Ideally that should be zero but a couple degrees timing correction is generally considered ok.

[RTPenland]

It's nice to see more tuners including logging software as part of their offerings, mission as an example gives you 2-clicks to save or export or send straight to mission. I imagine MHD does something similar, logging used to be a real PITA for the common man

[Throatpunch]

Use 93

[huzidada]

Originally Posted by cyam

I did some testing this weekend. I run MHD Stage 2 with a DP.

Running 98RON (93 octane) fuel and using MHD Stage 2 95 RON (91 oct) map and I get a max of 3 degrees pull back in timing.

Using the same 98 RON (93 oct) fuel and MHD's Stage 2 98RON (93 oct) map I get a max of 7 degrees pulled timing.

So even on the 95 map with 98 fuel I am getting pulled timing. Although a few degrees is acceptable, but not preferable. But the 98 map with 98 fuel - just no way, I can't run that map here in Australia.

The fuel quality in Australia is very bad. MHD saw my logs and said its the fuel.

So I run the 95RON map and put 98RON fuel.

So yes sometimes running a lower map than your fuel IS necessary. But you have to test and see what you can get away with.

I feel you, here in South Africa we get crappy 95 RON fuel!!!