2013 BD Pro with Low End Hesitation

[snowjunkie82]

I installed the turbo at 0 miles and the sled has worked great except for a low end hesitation when I tape the throttle from idle. The sled now has 300miles on it and I've tried every combination of tuning that I can think of. It is an intercooled kit with 2860 non tial turbo. We run 5000-8000 feet and use 75% 91 non ethonal, 25% C12 @ 9psi boost. I have also checked the tps witch was good and belt deflection (good also). Is there anything else I'm missing?

 

[philsummers21]

Hesitation as turbo lag or bogs then picks up. A turbo will always have a slight hesitation before boost picks up. There are ways to minimize it such as proper octane, more compression, lower gearing and clutching. Are you running the boondocker clutching?

 

[snowjunkie82]

It's showing the same the symptoms as a rich bog. I can take or add fuel and it does not change which makes me think I have an issue outside tunning. BD clutching.

 

[aus091]

what numbers are you changing to try to get rid of it? Do you tune with an afr or egt?

 

[Catmydoo]

My 13 did the same thing. I took fuel away from the non psi 4500 and 5500 at 99% tps. I can grab a hand full and its nice and snappy.

 

[aus091]

My 13 did the same thing. I took fuel away from the non psi 4500 and 5500 at 99% tps. I can grab a hand full and its nice and snappy.

did you take numbers away on the extra settings?

 

[Catmydoo]

I took it out of the first 2 rpm screens in the fuel menu. It might be smarter to take it of the xtra menu between say 4000 and 5500 rpm and a psi setting of 2-3 psi. I will try this next time i'm out.

My sled runs great, BD has put together a great kit for these sleds. My only complaint is the qd belt which with the help of boondocker Canada I might have that resolved.

 

[snowjunkie82]

I have EGT's on the sled, but the issue occurs pre boost (under 2psi) and under 5500rpm so there not much help. I've tried adding and removing fuel in the 4500 and 5500 RPM screens and up to 6700 PSI screens in all throttle positions. I've also used the extra screen and tried the ACEL screen. This is my third Polaris BD turbo sled so I have a fairly good back ground in tunning these sleds. It does not seem to be responding to any tunning on the bottom end. I'm not saying it couldn't be a tunning issue, but I have tried over fueling and under fueling the sled in this area to no change. I'm wondering if I could have a faulty box (I was told there is a reflash for the box for a faulty com connection). Or do I have something else going on. I also drained the gas tank and tried running the sled on 100% 91 non eth fuel to make sure I wasn't over octaining the mixture.

 

[aus091]

I have EGT's on the sled, but the issue occurs pre boost (under 2psi) and under 5500rpm so there not much help. I've tried adding and removing fuel in the 4500 and 5500 RPM screens and up to 6700 PSI screens in all throttle positions. I've also used the extra screen and tried the ACEL screen. This is my third Polaris BD turbo sled so I have a fairly good back ground in tunning these sleds. It does not seem to be responding to any tunning on the bottom end. I'm not saying it couldn't be a tunning issue, but I have tried over fueling and under fueling the sled in this area to no change. I'm wondering if I could have a faulty box (I was told there is a reflash for the box for a faulty com connection). Or do I have something else going on. I also drained the gas tank and tried running the sled on 100% 91 non eth fuel to make sure I wasn't over octaining the mixture.

I would have thought the extra numbers would clear that up. I think the accel numbers wouldnt do much in that way. Do you run the timing retard key?

 

[snowjunkie82]

I have the 3 degree timming key. Which I have tried with it unhooked to no change.

 

[philsummers21]

Whats your numbers

 

[snowjunkie82]

These are the numbers I ran last:
RPM 0 33 66 99
4500 0 0 -4 -5
5500 0 -3 -5 -8
PSI
4300 8 8 6 0
5500 12 13 20 19
6700 25 34 35 32
7500 25 30 38 41
8200 25 34 34 41
Xtra RPM Hi
Low Mid Hi
0 -02 -08

 

[Catmydoo]

If you roll on the throttle slow and smooth does it have the bog?
Mine was only when I hammered it from a dead stop and i think my 4500 is -10 and my 5500 -15 at the 99%. Not saying this is right but it cleaned mine up and my AFR numbers are still good while cruising down the trail.

By bog I mean the little hesitation before it takes off.

 

[snowjunkie82]

Just like you said. If I roll on I'm fine, if I hammer on it from a stand still it bogs. I will try your numbers tomorrow and let you know. Thanks for the info.

 

[snowjunkie82]

Just like you said. If I roll on the throttle I'm fine. If I hammer on it, it bogs. I will try these numbers tomorrow. Thanks for the info.

 

[Anthony Oberti]

Sure seems like a lot of octane if you ask me, but guess you already tried that. I am 33% 110 at 11lbs. Anyways, what primary spring are you running?

 

[snowjunkie82]

I agree that there is more octain there than needed, but I like to be on the safe side. The primary spring that I have been running is a 165/310 RCS titanium, but last two days I tried the spring that came with the kit witch I think is a polaris almond red.

 

[EZmoney]

Just like you said. If I roll on I'm fine, if I hammer on it from a stand still it bogs. I will try your numbers tomorrow and let you know. Thanks for the info.

Mine did this before bad bog in the bottom end.. I pulled fuel, added fuel,pulled my hair out. In the end it was a broked primary spring. Maybe have a look at your clutches.

 

[snowjunkie82]

Have had issues with these sleds eating primary springs in the past. Thats why I've switched to titanium springs. I'm quite sure the spring is fine, but I will check again.

 

[snowjunkie82]

Tried putting the numbers to where Catmydoo suggested and it cleaned up the bog. Guess I have to eat crow about knowing how to tune these things! What numbers are you running on the rest of the set up Catmydoo?