More dyno #'s Ported vs oem 100 vs 92 and ignition advance

[chadihman]

:crazy1:

:msp_wink:The truth is out there :msp_rolleyes:

What's that supposed to mean?

 

[exSW]

What's that supposed to mean?

Quote from a TV show called the X files,if you know it you are rapidly approaching old fart status....if you're not already there.

 

[splitpost]

Quote from a TV show called the X files,if you know it you are rapidly approaching old fart status....if you're not already there.

The problem is there was no kooky sountrack to back your post up

 

[exSW]

The problem is there was no kooky sountrack to back your post up

I thought about that.I'm sure there is a way to link a sound bite to a post.But I'm tech illiterate and besides the effect would be lost on those without speakers or turn them off(like me)

 

[blsnelling]

Ex set at 98 deg or 164 duration Intake set at 100 deg or 160 duration Transfers set at 116 deg or 128 duration. Blow down 18 squish .026

This saw runs a good bit better than my 461.

You need less blowdown and even more intake. I like only 15-16° of blowdown and the intake at 85°.

 

[chadihman]

You need less blowdown and even more intake. I like only 15-16° of blowdown and the intake at 85°.

Really? That's taking lots off the intake floor. I already lowered the base .050. I heard that lowering the intake that far just empties the tank faster.

 

[Hedgerow]

Really? That's taking lots off the intake floor. I already lowered the base .050. I heard that lowering the intake that far just empties the tank faster.

It does that too...

 

[old-cat]

R & D. Trial and error. 1 step forward ...........

 

[chadihman]

I'm surely not a porting pro but raising the transfers to high is bad

 

[old-cat]

Make tests exploring that aspect alone. Raise ten thou test, another ten ....

 

[Andyshine77]

I'm surely not a porting pro but raising the transfers to high is bad

Normally, but not every engine is designed the same, not every carb is big enough, the numbers Brad gave you work well and I've used them myself.

Great to see the dyno up and running. I think many will be surprised with some of the results, especially when it comes to porting, a few little things here and there often makes a big difference.

 

[Terry Syd]

Trimming the piston to change the timing can be an easy way to check your mods.

Say you lowered the jug and have the intake and blowdown the way you want them, but your unsure of the transfers. Since you lowered the jug, you know the transfers have less time/area than stock, which don't compliment the other changes you made to raise the cutting speed.

It's easy enough to trim a couple of degrees off the sides of the piston crown to increase the transfer timing. Give it a run and check the results. Trim some more off the piston and give it another run. Eventually, you start going backwards - so now you take the timing that gave the best results and cut that timing in the jug and install a fresh piston.

You can do the same with intake and exhaust. Pistons are cheap to cut up and you can do it in increments.

I never throw away an old piston if it is just worn. They can always be butchered up later for experiments. Using your dyno and a few pistons, you should be able to come up with a combination that you KNOW gives the best results.

 

[blsnelling]

I wouldn't throw numbers at you that would hurt your saw. These numbers are tested and proven. Try these numbers on some saws, and you kill them. As Terry suggested, there's not a thing wrong with trimming the piston skirt. You've probably already got the port shaped like you want, so that's what I'd do.

 

[wigglesworth]

Ex set at 98 deg or 164 duration Intake set at 100 deg or 160 duration Transfers set at 116 deg or 128 duration. Blow down 18 squish .026

This saw runs a good bit better than my 461.

I like those numbers....

 

[Terry Syd]

If you're starting from scratch with a cylinder, here's what I would do.

Since the transfers are the backbone of the powerband, I would work them over first. The time/area of the transfers sets the peak delivery ratio (peak torque) I would set them where I wanted them. If I wanted to increase the cutting speed by 10%, I would have to increase the time/area by 10%.

Increasing the time/area by changing the timing requires a complicated mathematical formula, however increasing the area is straight forward. If I increase the width of the transfer ports 10%, then the transfer time/area is increased by 10% - even I can do that math.

I can then set the intake timing to 160, which is a safe number to work with.

Next, I need to set the blowdown. I can try the stock exhaust timing, then trim 2 degrees of the front of the piston and try that, ... until I go too far. After I found the optimum blowdown, I can cut that into the jug. Pop in a new piston and I'm ready to go.

With that dyno I expect you are going to blow a lot of myths away.

 

[Mastermind]

Brad does build a mean 460.....

 

[blsnelling]

Brad does build a mean 460.....

Almost..........mean enough:msp_sneaky:

 

[chadihman]

Almost..........mean enough:msp_sneaky:

I'm tempted to send you a 460 to port.

 

[blsnelling]

I'm tempted to send you a 460 to port.

I'll make that a 1/2 price job, just to see the results on your dyno!

 

[hardpan]

i tested fuel some years ago, lower octane=more power

as long as your testing fuel, try oil ratio 50/1 40/1 32/1 20/1 16/1

you will find that the more oil =more power

I've been real curious about that. Most people do not consider oil to be fuel. You are saying not only is it fuel but real good fuel. Can't wait to see those tests.