[sickguy]

Hi all. I have a JB4 G5 ISO for my E90 N54, and a BMS DCI. I run the Map 5 with 40% E85, and it already maxed out the Map 5 with 17.5lbs of boost. I still have a BMS downpipe which I haven't installed yet.

So my question is will I see any performance gain with the downpipe, as I have already maxed out the Map 5 (I believe it only autotunes to 17.5lbs)? Or do I need to switch to other map to fully utilize the DCI and downpipe mods with 40% E85?

Thanks guys.

[Davyhay]

Even if you did not boost more than 17.5psi, you would see a large improvement just from the increased flow.

[Jeff@TopGearSolutions]

^ Correct

You'd also benefit from an intercooler too.

[sickguy]

Got it, so my best bet is running Map 5 with all the mods I have. Will it be safe and if there is any advantage if I change it to Map 7, which I think boost to 19lbs?

[MasterWang]

Downpipes will help with spool time as well.
Map 7 hits 18.5psi, but you need race fuel or 100octane (50-60% e85).
You need to log to make sure it is safe to run map 7.

[Jeff@TopGearSolutions]

Originally Posted by sickguy

Got it, so my best bet is running Map 5 with all the mods I have. Will it be safe and if there is any advantage if I change it to Map 7, which I think boost to 19lbs?

You must have the appropriate modifications to run Map 7. Aimlessly adding boost may not yield more power, in fact, if you add to much you are just over spinning your turbo's and ingesting your engine with hot air. In turn resulting in lower ignition timing and hindering performance altogether.

Don't think of boost as the only means of power.

Improving efficiency through downpipes and intercooler coupled with the appropriate boost timing and fuel will yield the most gains.

[MasterWang]

LPFP upgrade and BMS flash are recommended for map 7 on high e85 mixture.

[sickguy]

Got it, thanks guys.