[Terry @ BMS]

*** NOTE THIS IS NOT RELEVANT TO THE JB4 G5 BOARD ***

Hey guys,

As many know the JB4 G4 board has 18ohm load resistors built in which limit the amount of duty cycle the JB4 can add. The normal 18 ohm resistors limits performance to around 17psi/410rw depending on conditions. This is enough power to run high 11s in a properly setup car. For those wanting more duty cycle/boost you can replace them with 15 ohm resistors to allow another psi or so. Just keep in mind lowering the duty cycle safety increases your risk for motor or turbo failure. You must monitor ignition timing and ensure you have sufficient octane for your boost levels. If you are relying on meth for octane then you must be using a properly configured map 3.

As a general rule, if your FFMAX (wastegate adaption value) is sticking around 130, then you'll benefit by switching over to 15 ohms.


Tools Required:
2 15ohm 5watt ceramic resistors
1 580-620 ohm 1/8 watt resistor. Any resistance within that range will work.
Soldering Iron and Solder
Solder Sucker
Small Wire Cutters

Steps:
1) Cut off 18ohm and 820ohm resistors
2) Use solder sucker to clean out the holes
3) Insert new resistors
4) Solder them
5) Cut off extra leads
6) Verify solder is thorough and if needed clean with rubbing alcohol

Photos below are from a JB3. See JB4 reference photo for correct resistor locations.

[BSM 335I]

Good to know. Thanks T

[5soko]

Nice write up!!!

[Terrance28]

Hey Terry maybe you should post some of my diy pics on how NOT to do this haha.

[Terry @ BMS]

Originally Posted by Terrance28

Hey Terry maybe you should post some of my diy pics on how NOT to do this haha.

LOL there might be small children reading.

[TakeOne]

cool DIY Terry. Will 2.0 be self-adpating to whatever board one may have? Or will there be some checkbox to select?
I'm just trying to squeeze some 2.0 info out of you if you haven't noticed

[Terry @ BMS]

It will be self adapting to a degree but may require a few fields to be changed.

[TakeOne]

good stuff!

[Rysandro]

I have JB3 1.4, but don't know what board.

Does this mean I have a 24ohm board?

[Terrance28]

Yes unless you bought it used, just open the jb3 and check.

[Maxx2]

Terry,

Do you have the DigiKey part numbers for the resistors handy? Their website isn't the easiest to navigate. Looking to place an order asap.

Thanks.

[2008_335i_coupe]

I agree on the part number question.

[yandyr]

Originally Posted by 2008_335i_coupe

I agree on the part number question.

I just picked them up at a local eletronics / TV Repair shop.. there's plenty around everywhere...

[Terry @ BMS]

Use the link in the first post.

[JPSlick]

Terry I forget, does the 18 Ohm benefit the maps 1-7 too or just 8+.

Possibly define "tip top shape".

[Terry @ BMS]

Originally Posted by JPSlick

Terry I forget, does the 18 Ohm benefit the maps 1-7 too or just 8+.

Possibly define "tip top shape".

No, its not suggested for lower maps.

[2008_335i_coupe]

so can I add the resistors to a car with full mods (with meth) and run daily on map 7 or will I have to bump up to map 8?

[yandyr]

Originally Posted by 2008_335i_coupe

so can I add the resistors to a car with full mods (with meth) and run daily on map 7 or will I have to bump up to map 8?

You'll be fine on Map7, I have an 18ohm board and run Map7 daily.

[JPSlick]

Originally Posted by Terry @ BMS

No, its not suggested for lower maps.

Uh oh lol Ive yet to run it, but I was planning on running 7 with 93 + meth. Using map 8 for the days when I need to take someone out. I was under the impression the only thing that changes was basically there wasnt as much boost taper on the top end.

Just like the poster above I know someone else that has ran the 18ohm on lower maps, and there car didnt "appear" to have a problem. Just curious if you can let us know why its not suggested with some more detail?

[Terry @ BMS]

You're taking away safety for no upside. Also the targeting tuning is a lot more sensitive and sloppy with the larger load resistors.

[JPSlick]

Originally Posted by Terry @ BMS

You're taking away safety for no upside. Also the targeting tuning is a lot more sensitive and sloppy with the larger load resistors.

Are you then suggesting I run map 8 with meth daily? or converting back to 24 Ohm?

I feel like most people daily map 7 with the 18ohm all the time? Ive yet to hear this speculation and information up until today.

I understand the concern for the turbo at WOT, I just didnt know there was that much of a difference in the daily, low to no boost areas.

[Terry @ BMS]

Do a few JB3 logs on what you have and we can advise you based on that.

[Maxx2]

Terry,

I was reading hotrod182's thread "91 Octane + Meth=118MPH" and you wrote the following:

Originally Posted by Terry @ BMS

If you are on the modified board you'll make a little more peak boost on map 7, and won't run in to 30FF codes as easily on the higher maps. But at some point we just need to get an intake/IC/downpipes on your car.

Is this still valid with the new 2.0? If so, it sounds like what JPSlick is looking for. I was planning on running the same setup as well.

Wasn't hotrod182 using the 18ohm + Meth on map7 successfully with just DCI?

[Terry @ BMS]

I think I really spelled it all out in the first post. If the risks are worth it to you for almost no benefit on map 7, go for it!

[Terry @ BMS]

As we're getting more and more 18 ohm data updated the first post and removed some posts related to changes in the suggestions for use.