Why Stroke it?

Foxfan88 · Jun 21, 2005

since the smaller motor has a shorter stroke, the shorter amount of time it takes to go through that stroke, this means more lower end, the motor is working faster... or something

stang8urimport · Jun 21, 2005

Steve-Os95GT said:
Why stroke it?

Cause it feels so good?

bluevenom867 · Jun 21, 2005

Foxfan88 said:
since the smaller motor has a shorter stroke, the shorter amount of time it takes to go through that stroke, this means more lower end, the motor is working faster... or something

2500rpm's is 2500rpm's regaurdless of stroke size.

90mustangGT · Jun 21, 2005

bluevenom867 said:
2500rpm's is 2500rpm's regaurdless of stroke size.

Yes, but piston speed will be greater, I think that is what he was getting at, and it is true. The 347 will pull in more air at 2500 than the 306 will at 2500.

bluevenom867 · Jun 21, 2005

90mustangGT said:
Yes, but piston speed will be greater, I think that is what he was getting at, and it is true. The 347 will pull in more air at 2500 than the 306 will at 2500.

I never said anything about piston speed.As a matter of fact,piston speed is good.Because at higher rpm's the air flows better when the piston speed is higher (because there is less TDC dwell time).

Aliate X · Jun 21, 2005

You guys should go check out AFR's website.

Using a crazy setup with 13:1 compression, they made 751hp out of a 347.

Heres the link, 2nd setup from the bottom.

http://airflowresearch.com/ (click on dyno tests, and then ford dyno packages, not 5.0)

90mustangGT · Jun 21, 2005

Aliate X said:
You guys should go check out AFR's website.

Using a crazy setup with 13:1 compression, they made 751hp out of a 347.

Heres the link, 2nd setup from the bottom.

http://airflowresearch.com/ (click on dyno tests, and then ford dyno packages, not 5.0)

No suprise there, but I can gaurantee it's no budget minded street motor. I mean look at NASCAR, 358cid, all motor, pushrod motors making 700-800HP.

A buddy of mine has a 351W stroker built with the best money can buy pretty much and that motor can rev to 9000rpm and is suposed to make between 660-680rwhp all motor before the 300shot.

89CopCoupe · Jun 21, 2005

Steve-Os95GT said:
So let me get this right. You are saying that those type of numbers on a 302 are feasable but not recommended do to longevity with that type of strain? BTW, thanks for all the help guys.

I'll hit some basics:

Think of your engine as a set of 8 syringes.
The 347 piston (plunger) travels further down in the cylinder (syringe) ...
...this is why it has the larger designation 347 vs 306 (cubic inches).
A syringe that travels further (with the same diameter bore) will pull in more ... in this case air and fuel.

Now look at piston speed ...
... a 347 has to travel a greater distance in the same amount of time ... 2500 rotations per minute (rpm) is 2500 rotations per minute no matter what the engine size ...
...This means a 347 piston travels faster in the cylinder than a shorter stroke 306.
A faster moving piston will pull air and fuel in with greater force referred to as "velocity".

Then we have intake port size ...
... these are the tracks that air & fuel travel though to make their way into the cylinder.
Think of these as straws attached to the end of the syringes.
Too large of a straw will make the incoming air & fuel "lazy" ... as in poor velocity.
Too small of a straw creates restriction ... not enough volume can be supplied as the engine desires ...
... Kinda like trying to suck up a McDonald's shake
You want these head and intake port tracks to be the appropriate size for the engine combination you are building.
A larger port requires a smaller engine (306) to spin faster in order to create enough velocity to pull and push the fuel in and out of the engine ...
Or a larger port needs a larger consuming engine (347) to keep the air from being too lazy
... Driving a street car around at 3500rpms all day long is

So to wrap this essay up, a 347 will create more consumption (power) than a 306 in the same amount of time ...

That is the whole name of the game ... get more air & fuel in and out of the engine in the least amount of time ... that's why a top fueler is so beastly ... it is very good at doing this

90mustangGT · Jun 21, 2005

Well said 89CopCoupe.

89CopCoupe · Jun 21, 2005

90mustangGT said:
Well said 89CopCoupe.

I wish amateur (me) advice was worth something ...at least a nickel

cjman15 · Jun 21, 2005

Steve-Os95GT said:
Why stroke it?

That's what she said!!!

Scorcher2005 · Jun 22, 2005

Foxfan88 said:
since the smaller motor has a shorter stroke, the shorter amount of time it takes to go through that stroke, this means more lower end, the motor is working faster... or something

no, the shorter the stroke usually just means it can rev faster/higher more safely

speedracer238 · Jun 22, 2005

Steve-Os95GT said:
95GT
Edelbrock Heads (out the box)
Shorties, pullies
CAI, stock intake
Lifters, rockers.... that is most of it.
292rwhp
324rwtq

So you are almost putting down 300 hp to the wheels with a stock intake, stock cam, and no boost??

Please tell me ur secret cause thats next to impossible.

giddyup306 · Jun 22, 2005

89CopCoupe said:
I think the obvious "gear head" advantage is the increased vacuum ...

Please tell me how a stroker motor would create more vacuum. However if you ment volume I would agree.

Modular2v · Jun 22, 2005

giddyup306 said:
Please tell me how a stroker motor would create more vacuum. However if you ment volume I would agree.

i think it creates more vacuum because it is wanting to pull more air in due to the increase in displacement

Flavadave4 · Jun 22, 2005

TheUser said:
I think you answered the question yourself. More power w/ the same combo is probably why people do it. More cubes w/ the same size block. A lot of people don't want to run a big block, which is bigger/heavier, maybe a little more work to fit in and is obvious. No one will ever know you have a stroker unless the motor is torn down or you tell them. BTW, 15% of a 300hp motor is 45hp...not to shabby.

There's a lot of threads detailing pro's and cons of each if that's a consideration for you.

im with him

bluray · Jun 22, 2005

So basically stroking a 302 would decrease speed and power in the lower end rpm? If so than a person with a 302(or if I understand correctly, any type of engine) that uses his ride for more than 80% street driving would not want to stroke the engine because it would reduce performance in the lower rpm(which is probably 90% of the time on the street) and increase fuel consumption lowering milage, right?

bluevenom867 · Jun 22, 2005

bluray said:
So basically stroking a 302 would decrease speed and power in the lower end rpm? If so than a person with a 302(or if I understand correctly, any type of engine) that uses his ride for more than 80% street driving would not want to stroke the engine because it would reduce performance in the lower rpm(which is probably 90% of the time on the street) and increase fuel consumption lowering milage, right?

Were you even looking at the post above?

Its usually quite the opposite effect,you gain power and especiallly torque throw out the entire rpm range.

Steve-Os95GT · Jun 22, 2005

speedracer238 said:
So you are almost putting down 300 hp to the wheels with a stock intake, stock cam, and no boost??

Please tell me ur secret cause thats next to impossible.

Forgot to mention the cam, E 303 I think. It was already on the car when I bought it. There might be one or two more things but I can't remember.

bluray · Jun 22, 2005

bluevenom867 said:
Were you even looking at the post above?

Its usually quite the opposite effect,you gain power and especiallly torque throw out the entire rpm range.

Yikes, sorry sorry! There are lots of opinions going around here.

So then there would be increased power and torque at the lower and higher rpm, but fuel consumtion would still increase reducing milage. That sound right?

Why Stroke it?

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