[birdman]

I currently have the Bren tune and noticed a nice gain in performance. However, I feel I’m running lean at low rpms. I’m considered installing a BP.
Has anyone installed the bren tune with a booster plug? Any reasons why I shouldn’t attempt this? Thanks and ride safe! 😎

 

[BaldyDave]

What makes you think you are ruining lean? What symptoms is the bike displaying?

I have a Bren tune and have to say it works very well at low rpm too. I used to have a Booster Plug installed before the Bren and it made a positive difference, but I removed it before using the Bren Tune and have to say I didn't notice any major throttle control differences down low, the Bren actually improved the low rpm stutter that sometimes happening when blipping the throttle so it almost never happens now. There was no improvement in low throttle smoothness over the Booster Plug (which greatly improved the stock throttle response) but the Bren Tune really woke the engine up especially in the Mid and High rev ranges. Totally different bike and the mid range flat spot was entirely eliminated. The bike is now the way BMW would have wanted it to be if they didn't have to worry about noise and emissions regulations.

My gut instinct says not to mix a BP with a BREN tune, although to be honest I don't have enough expertise to give you an explanation why. All I will say is that the Bren tune should have tweaked the AFR to the most favourable figure for engine performance and should have eliminated the lean running that stock bikes are set up with (If I am understanding things correctly). If there is something wrong with how your engine runs, personally I'd be looking for another cause at this stage.

 

[Ian_H]

I'd second @BaldyDave 's view.
I have BrenTune and would be very surprised if your bike is running lean.
Adding a BP could make your engine run too rich IMO and likely cause issues like plug fouling and maybe a loss in performance.

 

[birdman]

I think I'm running lean because sometimes when I'm stopped and I blip the throttle I get a weird response. Almost as if the engine is about to stall out. I've never had a stall this way. When I first put her on the dyno after I installed the tune i was running lean in the 4-5k rpm range in a 4th gear pull. This was before I got the catless exhaust installed. I have yet to run the dyno again since installing my catless pipes.

The Dyno at my shop is currently not working. I'm planning to drop her off in a couple weeks to get new handlebars, lines, and levers installed. As well as get some parts powder coated. I will also try to get another graph.

What would you guys recommend? I don't want to mess too much with tuning. I've heard bricking the ECU on these bikes isnt hard. I would hate to have to buy a new ECU. Could I maybe install a power commander and fine tune my AFR with dyno runs?

 

[if0rg0t2remember]

Even if you are running lean in some spots in your throttle range, why would you double up on addone rather than just contacting BrenTune and requesting a revised fuel map?

 

[birdman]

Even if you are running lean in some spots in your throttle range, why would you double up on addone rather than just contacting BrenTune and requesting a revised fuel map?

I've tried contacting Bren and they don't seem to really want to help. They say that the tune is perfect the way it is. I'm still waiting on actual graphs, with the catless headers, to send to them. Only problem is that I haven't been able to use the dyno because it has been offline.

The main area of concern is the engine stumbling when I blip the throttle. Of course maximum performance is also high on my priority list.

 

[Ian_H]

Worth checking this thread.... hesitation on snap opening throttle at idle has been seen by a few people - with and without BrenTuning.

Stumbling/Hesitation @ Idle

Like many big singles and twins, the R9T doesn't seem to appreciate having the throttle snapped open (at least my Racer doesn't). Being just slightly progressive helps miles. To me that's a characteristic rather than a fault. But you shouldn't have to coax it.

www.ninetowners.com

 

[BaldyDave]

Exactly so @Ian_H - I was going to direct @birdman to that thread. This is not an uncommon issue that I experienced too - especially when the bike was stock, its now greatly reduced, but not gone altogether. I just live with it, for me its no big deal.

 

[birdman]

Exactly so @Ian_H - I was going to direct @birdman to that thread. This is not an uncommon issue that I experienced too - especially when the bike was stock, its now greatly reduced, but not gone altogether. I just live with it, for me its no big deal.

Hey Baldy have you ever put your 9T on a dyno and got a reading?

 

[BaldyDave]

Nope mate, to be honest I've never felt the need. The differences and improvement were obvious to me so that was all I needed.

 

[birdman]

Nope mate, to be honest I've never felt the need. The differences and improvement were obvious to me so that was all I needed.

I felt the same way after the tune but I was curious to see actual numbers. Thats just me.

 

[Phenix3939]

Are you running an exhaust, headers or intake? Or just the tune? I've got all the above and the Bren tune and I've got no problems.

 

[birdman]

Are you running an exhaust, headers or intake? Or just the tune? I've got all the above and the Bren tune and I've got no problems.

running full titanium exhaust.
Here’s a picture

 

[Dirtmerchant]

@birdman, nice jeep....





haha, just kidding, beautiful FJ!!!

 

[birdman]

Here a picture of the latest dyno run. I'm worried I'm running lean; I've had more "stutters" and even stall outs when approaching a red light and dropping down into first gear. Compared to strictly power. My original runs with stock headers showed almost 10 more HP. I wasn't able to get AFR because of the cat so I cant compare that. I don't care about the power anymore. I love my 9T and the pipes I have now. I just want to get her running as perfect as possible.

Bren is not being too helpful for me. They've asked me to keep getting more dyno runs because of numerous different things. First they wanted an AFR reading so I had a wideband bung welded on my pipes. Now, they're telling me its "hopping on the roller" and that's what's creating those dip or bumps in the graph. At the lowest point on the AFR scale it drops down to about 11.9 in the 7k rpm range. I'm not sure if its just my pipes that are really impacting the performance or if I can actually make valuable changes to the fuel map. I'm open to any ideas you guys may have for more diagnosing.

After reading a few different threads I know the lean running engine is the nature of the beast. I live and Florida and it is HOT right now. I've noticed the stalling is more frequent when my engine is hotter rather than just starting her up cold. But again that makes my think why would it happen if the engine is hot? Does temperature really affect the fuel ratios or am I missing something?

 

[Ian_H]

I'm not an expert.
But I don't get any of the issues you describe with my Bren tune.
What map did you ask for ? I told them I run full de-cat with super unleaded - 99ron in the UK.
BMW needed to do a bunch of stuff on my engine last year when I had an unrelated issue and told me I was running rich - which I was happy with TBH. (Although it does mean I only get 44 mpg which I think is low???)
One idea - re-load your original map. Did you keep a copy?
Then re-load your Bren-tune map. See what change you notice in terms of stalling.
@birdman

 

[birdman]

I'm not an expert.
But I don't get any of the issues you describe with my Bren tune.
What map did you ask for ? I told them I run full de-cat with super unleaded - 99ron in the UK.
BMW needed to do a bunch of stuff on my engine last year when I had an issue and told me I was running rich - which I was happy with TBH.
One idea - re-load your original map. Did you keep a copy?
Then re-load your Bren-tune map. See what change you notice in terms of stalling.

I asked for the same as you. Catless-93 octane, here in the US. Same exact tune. I've seen people are very satisficed with the Bren map but I am not right now. However, the reason I had to get a bung welded was because my pipes actually have a "mini-cat." As you can see they are staight pipes, but somewhere in the middle the is some kind of cat converter about 2-3 inches long. See the marking in red on the photo.

I will try reverting it back to the stock map. I wanted to try that anyway.

 

[Ian_H]

By the way - air temperature has a big impact on performance.
All engines like cold dense air.
It's why you see air/charge/intake coolers - the colder the air the more bang you can get and the more performance you see.
Turbo cars always perform better in colder conditions.
And conversely, the hotter the temps - the more likely you are to run lean.
(Sorry - just realised I might be "mansplaining" the obvious here :-( )

 

[birdman]

By the way - air temperature has a big impact on performance.
All engines like cold dense air.
It's why you see air/charge/intake coolers - the colder the air the more bang you can get and the more performance you see.
Turbo cars always perform better in colder conditions.
And conversely, the hotter the temps - the more likely you are to run lean.

I figured that had something to do with it. Its like 90+ F in Florida right now with unbearable humidity.

 

[Manyakus]

Unplug one of your OEM lambda and install the wideband there. You will have a reading before CAT...then you can re-run your dyno.

The ECU can still run and function on one OEM lambda.