Stock clone cam duration + 1.3-1 rockers

[Modding_out]

I'm experimenting with intake runner length and I need to know what is full duration of the stock cam as well as how I can calculate 1.3-1 rockers into the ratio as I'm well aware the duration will change once installed.

Any help would be appreciated as I need to know this before I can draw up my plans:thumbsup:

 

[Oldschool]

seems to me its 221.

I don't think your going to see a change in durration.

I understand what you are trying to achieve with different runners but i don't think your going to gain much.

 

[v6steeda]

That's correct, duration will not change. Lift will change and this will need to be factored in when selecting the valve spring rate. I hope that helps.:wink:

 

[Modding_out]

I could have sworn MDB said once that duration changes lightly.....maybe it was typo?

Any way I'm shooting for a 3000rpm kick, which happens to be roughly around the same rpm as my clutch engagement, I have yet to throw my tack on and check for sure but it was spot on at 2100 rpm before I tweek'd it.

I'll post up my calulations and findings but for now I'll just say I bought a 22mm pit bike carb for this "build"....more like experiment:doah:. I'll also place a order for those rocker arms and guide plate from the OldMiniBikes ware house:thumbsup:

 

[65ShelbyClone]

Seat-to-seat (advertised) duration won't change; the @0.050" duration will.

 

[Modding_out]

OK if the duration won't change the lift will, how would I add that percentage of gained lift to the stock lift(what ever that percentage may be.

I also received my new pz22 clone

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[65ShelbyClone]

Multiply the lobe lift by the rocker ratio. If all you have is lift at the valve, then divide that by the rocker ratio to get the lobe lift.

 

[Modding_out]

Thanks! I'll start working on how long it needs to be:thumbsup:

 

[Modding_out]

The link explains what I'm going to do nicely:thumbsup:
Ram Theory

Stock cam duration is 221* (thanks btw)
Engine rotates twice for the intake to open once, So 720* - 221*= 499* of crank rotation with the intake closed

At 2900rpm,499* time elapsed is .0287 seconds

Formula -> 2900rpm/60sec=48.33 rev-sec. 48.33rev-sec x 360*rotation =17398.8. 499*/17400= .0287 sec
1,125 fps X .0287 sec = 32.2875 32.29 feet of travel, divide by 2 = 16.15 feet for the sound wave to bounce and come back once.

Now comes the trial and error to find how many times you can get the wave to wave to bounce and still maintain a manageable runner length nascar uses 3 waves . but the point is to reduce the number of waves to a minimum.

To be continued......

 

[Oldschool]

I once made a 11 foot long ram pipe out of PVC for a diesel.

it made a lot of difference at 1500 rpm.

Ram pipes do work at limited rpm ranges a lot like tuned expansion chambers on 2 strokes.
trouble is the biggest gain in one area will hamper you at lower or higher rpms when you are out of tune....

 

[65ShelbyClone]

At 2900rpm,499* time elapsed is .0287 seconds

Formula -> 2900rpm/60sec=48.33 rev-sec. 48.33rev-sec x 360*rotation =17398.8. 499*/17400= .0287 sec
1,125 fps X .0287 sec = 32.2875 32.29 feet of travel, divide by 2 = 16.15 feet for the sound wave to bounce and come back once.

Now comes the trial and error to find how many times you can get the wave to wave to bounce and still maintain a manageable runner length nascar uses 3 waves . but the point is to reduce the number of waves to a minimum.

The waves diminish in energy each time they reflect, so for that reason it's better to grab the return wave as soon as possible. The problem is striking a balance between engine rpm and runner length. As you have found in doing the math, catching the wave on it's first trip back to the valve would require a 194" runner length, which is impractical to say the least. Like Oldschool said, resonant tuning is a tradeoff; length that helps at one end of the RPM spectrum will hinder at the other. That's why Ferrari used variable-length trumpets on their V10 F1 engines before the FIA banned such systems(like they eventually do to everything ).

Here is an interesting site I found several months ago documenting an engineering project on the subject of induction tuning on a Suzuki bike:

The Graben:. Pulse Ram Induction Theory

One thing I don't like is that in the beginning he says forced induction increases volumetric efficiency(VE), which is not true. It also was never seen through with a finished setup being run on a dyno; the results were only predicted based on the experimental data. Still gave me some ideas, though.

Also, if you want to insert the degree symbol ( ° ) somewhere, turn on number lock on the keyboard, hold the Alt key, and punch in 0176 on the number pad. Google "alt codes" for all the other special symbols that are inserted the same way.

 

[Modding_out]

Thanks! that's a good link....I was wondering how to insert a degree symbol:laugh:

 

[Oldschool]

that deg thing is a pet peaev isn't it?

Sadly I am technological impared and can't make ythe leap to things like spell check and these mad codes you speak of.....

Mad code lol.....
Intel instruction set from the 80s when I learned to key machine code into the 8085 and make a diode matrix for it too boot strap.

How the world has changed.

 

[65ShelbyClone]

Intel instruction set from the 80s when I learned to key machine code into the 8085 and make a diode matrix for it too boot strap.

How the world has changed.

Come on, man, we're cookin' with 8088s these days. :lol:

 

[Oldschool]

You do much with computers?
that specific chip was was designed to process at 16 bit but opperate on the 8 bit bus that the older chips like the Z80 and 8085 used.

The mars rovers that lasted so long ( launched how many years ago 5-10 ? ) used the 8085 because it was so reliable ( militarized versions were made an in that case used ).

Hmm.....
My XT had a 8088 in the mother board and a 8085 or 8080 in the key board to feed my key strokes to the main processor.

The z80 ( mor eor less the same as the 8085 instruction set made by Zilog )went on to become the most common chip in everything form dish washers to microwaves. i think that ersion is the z8000 now last time I payed attention it was modified with a shit load of extra holding registers so it could perform simple tasks without resorting to ram for a lo to its functions.

 

[65ShelbyClone]

You do much with computers?

Yeah, but apparently not like you do. I just threw the 8088 out there because it was introduced to market after the 8085, thus making the 8085 seem comparatively outdated to casual readers(even though both are positively ancient). :wink:

I can't stand programming, actually. I am a fan of vintage electronics, though.

 

[Oldschool]

Yeah, but apparently not like you do. I just threw the 8088 out there because it was introduced to market after the 8085, thus making the 8085 seem comparatively outdated to casual readers(even though both are positively ancient). :wink:

I can't stand programming, actually. I am a fan of vintage electronics, though.

I used to be in the automation buisness.
Automated myself right out of a job at one point lol.

I like vintage electronics too but these days I confine my tinkering to things with point to point wiring and vac tubes.

 

[Modding_out]

My initial plan was to just have the ram tube curve upward and over the engine in between the tank on my mb165

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But what do you think if I also welded bender washer every half inch along the length the tube after I bent it into position?
Further expanding on the idea I have a small squirrel cage blower (3"x3") and my engine is lighting coil equipped. I have a few 21turn 16v 550can motors off of a traxxas emaxx that should be more that adequate to power the fan. (shroud will wrap around the intake)

The reason why i want to do this is to chill the header and hope fully create a denser fuel charge.

And of you really wanted to get crazy...think back to high school chem class you'll recall that water takes 4x amount of normal energy required to heat it up one degree....this also works in reverse water will cool off the heat source 4x faster than air ever could. So if I dripped water inside the blower it would mist out and evaporate from the air rushing by further chilling the fuel charge.

Am I on to some thing or just a little crazy?ut:

 

[65ShelbyClone]

I think it would be a lot easier to just burn methanol instead of building a swamp cooler for the intake. A finned tube would not do a very good job at transferring heat away from the intake air anyway unless you did something to increase the internal surface area as well without obstructing flow. The inside of an intercooler core should give you an idea. Lastly, electricity isn't free, so whatever wattage goes into the fan is going to come out of the available power to move the bike. You'll have to weigh that loss against any potential gains and determine if it's worth doing.