A R E A 51 Pit Bull has become a little H O G!

[subhunter]

Im new so i gotta ask....

What preformance increase do you see by adding the finger ports?
BTW the jug looks wicked

 

[PasoRoblesJimmy]

Looks good. You might not be able to do much with that intake boot. It looks kind of fragile. The size of the carb venturi or carb throat is probably the limiting factor, anyway.

The name of the game is achieving optimal flow of the fuel/air mixture in terms of molecules (or moles) per second.

The quantity of the flow is determined by both the size of the opening and the velocity of the flow going through it.

Optimal flow is a trade off. The size of the opening will eventually reach a point of diminishing returns. Testing and experimentation can be lots of fun though.

 

[CHEVYTOWN13]

Joseph, they promote more flow. Although, finger ports are stand alones. I added mine directly into the transfer port.

I'll be getting a 7900 cylinder soon to try out my first true finger ports.

Performance gains I have seen are constant RPM throughout the cut and the throttle response is nice too.

What! Professor Jimmy in da house! Man, I should have picked your brain more at our GTG!!!!!!!!!!!!

I just matched it to the opening of the intake. It was a little tricky, but not that bad. It came out OK from viewing through the carb.

 

[subhunter]

So the finger ports in a sence are like a totally new transfer duct?

 

[roncoinc]

Looks good. You might not be able to do much with that intake boot. It looks kind of fragile. The size of the carb venturi or carb throat is probably the limiting factor, anyway.

The name of the game is achieving optimal flow of the fuel/air mixture in terms of molecules (or moles) per second.

The quantity of the flow is determined by both the size of the opening and the velocity of the flow going through it.

Optimal flow is a trade off. The size of the opening will eventually reach a point of diminishing returns. Testing and experimentation can be lots of fun though.

Aha,very good Jimmy...
when looking for more flow you have to ask WHY ?? is it to just dump more raw fuel in or to have more velocity and atomization ??
i go with the later..
case in point is the 84cc BB kit for the 64cc dolkita...
same carb,at 84cc the saw screems....the carb supplies plenty of fuel but the bigger cc drawing more supplies the velocity AND the fuel..
the carb boot IS an impediment and nothing can be done about that..doing little things help but my main concern is the free flow of air getting TO the carb..another case in point,the HD air filter kit for the dolkita's..
consider any race engine that uses free flowing air filters..theres a reason for that..

Fine job Rick..

 

[PasoRoblesJimmy]

Aha,very good Jimmy...
when looking for more flow you have to ask WHY ?? is it to just dump more raw fuel in or to have more velocity and atomization ??
i go with the later..
case in point is the 84cc BB kit for the 64cc dolkita...
same carb,at 84cc the saw screems....the carb supplies plenty of fuel but the bigger cc drawing more supplies the velocity AND the fuel..
the carb boot IS an impediment and nothing can be done about that..doing little things help but my main concern is the free flow of air getting TO the carb..another case in point,the HD air filter kit for the dolkita's..
consider any race engine that uses free flowing air filters..theres a reason for that..

Fine job Rick..

Just "What if?' brainstorming by a retired engineer. I've learned from experience over the years that it pays to look beyond individual components and look at things as complete systems.

The replacement K&N air filter on my 89 Chev pickup with 350 V8 gave a noticeable gain in uphill pulling power. Tires would easily chirp when accelerating from a dead stop.

For maximum exhaust flow or scavenging, auto exhaust systems from the cat back have to be viewed as a single tuned unit. Just slapping a free flow muffler with bigger openings into an existing exhaust system can actually result in a decrease in scavenging.

 

[CHEVYTOWN13]

Yes, extra transfer ports.

Jimmy and Ron kicking some arse

 

[roncoinc]

Just "What if?' brainstorming by a retired engineer. I've learned from experience over the years that it pays to look beyond individual components and look at things as complete systems.

The replacement K&N air filter on my 89 Chev pickup with 350 V8 gave a noticeable gain in uphill pulling power. Tires would easily chirp when accelerating from a dead stop.

For maximum exhaust flow or scavenging, auto exhaust systems from the cat back have to be viewed as a single tuned unit. Just slapping a free flow muffler with bigger openings into an existing exhaust system can actually result in a decrease in scavenging.

Another good one Jimmy..
the in and out are on oppisite ends but DO make up the complete system..what goes in has to go out ! however on like Rick's saw the intake is is such a poorly designed system the only room for improvement IS in the little things..if we could stick a K&N on them a "lot" of the problem would be solved..also Rick likes to tinker and doing small things "can" add a little..i have also told him a well set up carb and tuned right is probly responsable for the most gain to be found..
i think Rick has the exhaust down,i see his pipes
I have seen the same as you..a little 1 1/4 exhaust pipe with a cherry bomb as a muffler ?? so you got a bulge in a part of the exhaust pipe,for what reason ??
so lets work on an air injection system for the intake i aint talking strato either !!
all saws come with a built in blower and some use it to inject air into the airbox..it needs to be filtered and injected into the carb now..
brainstorm on that one a bit..the air compressor is there already..
possabilities ??

 

[CHEVYTOWN13]

Up in smoke

Ron, the carb kit came today thanks to one of our sponsors. That was quick service!

 

[CHEVYTOWN13]

If anyone stumbles in here to answer the question

I was ready to take compression readings on the The Hog™ when I remembered there was no fuel in the tank.

Is it best to take compression readings while there is fuel in the system? Would a dry compression reading be way off compared to actual using conditions where there is fuel in the chamber? (not sure if I'm making sense) I would imagine that would boost compression a bit.

 

[roncoinc]

I was ready to take compression readings on the The Hog™ when I remembered there was no fuel in the tank.

Is it best to take compression readings while there is fuel in the system? Would a dry compression reading be way off compared to actual using conditions where there is fuel in the chamber? (not sure if I'm making sense) I would imagine that would boost compression a bit.

It may make a little differance because the cyl wall not wet at all,but not much..
take it as is,then fire it up and get it wet and do it again and see..
of course as the rings seat comp will go up ,so all your doing is getting a base line to see how much it goes up to..
hope that helps.

 

[CHEVYTOWN13]

Sounds like a plan Ron.

Thanks brutha.

 

[roncoinc]

Sounds like a plan Ron.

Thanks brutha.

Nada..

 

[CHEVYTOWN13]

De nada buddy

I'll have a vid tomorrow after a couple of heating cycles.

Same 20" bar and chain and Elm.

 

[ronT2]

Hey CTown, looks like the saw is running great.

If you have anything like this give them a try on that intake boot. I’ve ground a fair amount of rubber and have a feeling they’d do real good. The finish might be a little rough but that could be taken care of with a regular old grinding stone.

 

[CHEVYTOWN13]

Thank you Ron. I can't wait for red light in the morning...

Ron, I cant see the photo. It's probably the iPhone that I'm on. When I get home, I'll check it out.

 

[ronT2]

Don't blame the phone, the pic didn't upload. I can't see it either on a different computer. It's just a pic of those small drum sanding tools, they should work great on rubber/plastic. I'll try to upload again when I get home.

 

[CHEVYTOWN13]

No worries Ron. I have some tech problems too. I'll have to use the 18" bar instead and a different chain.:censored:

 

[CHEVYTOWN13]

I didn't bother with the heating cycles. So the next couple of start ups should wake up the saw again. As is it feels real good and the motor sounds like a crazed maniac on the last WOT blip. You ever see the movie Kafka(1991)?

Letting the saw cut first and then putting pressure towards the end. A worked up freshly filed chain on the last of its filings. I did something wrong as the left cutters are shorter than the right:monkey: I haven't cleaned the gullets eigther:monkey::monkey: I won't be attempting 3 cuts anytime soon too:help:

Letting the saw warm up on the first cut. Someone said they were going to send me their racechain. Where is it CW Also, since it was an 18" bar, I thought it only fair to cut a bigger piece.

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I'll try again but with a square filing. Wont be correct, but should cut well for the short amount needed. I'm just glad the filings aren't beaked any more! I'll also take the time to clean the gullets.

 

[AUSSIE1]

Saw is skedaddlen there Rick.

I must get a tach on the 365 some time