Bg86 exhaust mod?

[Gerbutt]

Hi

 

I was wondering if anyone had drilled the exhaust of a bg86 exhaust? I know being louder is not so good on a blower and also bring at full revs for long periods, but I just wonder if like an ms150 it'd give it loads more power?

 

 

Sent from my iPhone using Arbtalk

[Arbtech Tree Services]

The airflow (velocity and volume) is directly linked to engine rpm. If the engine is already achieving max rpm then no amount of extra power will make any difference, so drilling the exhaust will only serve to increase noise levels and void any warranty on the machine.

 

Regards,

 

Steve.

[spudulike]

I drilled the exhaust making the tube coming from it pretty thin. I also lowered the squish and ported my BG85, it pulls around 9500rpm rather than the standard machines circa 7500rpm.......TBH, I was bored one day:001_rolleyes:

[doobin]

There may be a little bit more power to be had (if you cover the nozzle the revs rise so the airflow is indeed providing resistance and therefore defining the top end of the revs), but on a blower what's the point? It won't help you get the job done faster, if you're thinking you need more airflow then it's time to pick the rake up for a couple of minutes and clear the pile

[spudulike]

The airflow (velocity and volume) is directly linked to engine rpm. If the engine is already achieving max rpm then no amount of extra power will make any difference, so drilling the exhaust will only serve to increase noise levels and void any warranty on the machine.

 

Regards,

 

Steve.

 

I don't quite follow your statement but in my experience, if the flow of the engine is increased through porting/mufler mod, the flow through the carb is increased and generally, this will pull through more fuel with the carb settings left on standard settings.

 

The carb will generally need leaning up slightly on a ported engine to obtain the correct mix and the extra engine flow will increase the power and allow the blower to run faster/higher revs - well that is what occured on mine when I played with it!

[Gerbutt]

I was just wondering really, it made such a big difference to my 150, and those blowers sound bunged up just like it used too. I'm sure it'd increase revs.

 

Can you take a little vid of yours sometime spud?

 

 

Sent from my iPhone using Arbtalk

[spudulike]

There may be a little bit more power to be had (if you cover the nozzle the revs rise so the airflow is indeed providing resistance and therefore defining the top end of the revs), but on a blower what's the point? It won't help you get the job done faster, if you're thinking you need more airflow then it's time to pick the rake up for a couple of minutes and clear the pile

 

Mmm - I ported my strimmer, hedge cutter, blower and every saw I have:blushing:

 

Guess I can't help myself:lol:

[Arbtech Tree Services]

The airflow (velocity and volume) is directly linked to engine rpm. If the engine is already achieving max rpm then no amount of extra power will make any difference, so drilling the exhaust will only serve to increase noise levels and void any warranty on the machine.

 

Regards,

 

Steve.

 

I don't quite follow your statement but in my experience, if the flow of the engine is increased through porting/mufler mod, the flow through the carb is increased and generally, this will pull through more fuel with the carb settings left on standard settings.

 

The carb will generally need leaning up slightly on a ported engine to obtain the correct mix and the extra engine flow will increase the power and allow the blower to run faster/higher revs - well that is what occured on mine when I played with it!

 

Spud,

 

I was basing this on the engine already achieving max rpm ie. limited coil, however if the engine rpm can be increased by producing more power then obviously throughput of air (on the blower side) will increase proportionately.

 

Regards,

 

Steve.

[Gerbutt]

When they start to run out of fuel the revs increase so I presume they're not at the limiter yet? If it also sucks your tshirt over the intake the revs go up too?

 

 

Sent from my iPhone using Arbtalk

[spudulike]

When they start to run out of fuel the revs increase so I presume they're not at the limiter yet? If it also sucks your tshirt over the intake the revs go up too?

 

 

Sent from my iPhone using Arbtalk

 

My BG85 coil wasn't limited so was able to get a bit more out of it. I didn't want it to be stupidly loud as I use it around my property - usually to mess up the wifes hair, gives me a laugh:blushing:

 

Video - really.....it isn't that interesting:lol: