7m stroker kit?

[7MGTEsup]

It's 6.5mm more stroke that when added to the increased bore equals 665cc more cubes of usable power!

That's a 328cc+ increase for Non-Turbo motors!
That's a 115cc+ increase for Turbo motors!

So which is it 665cc or 115cc???

After 4 months of Dyno Testing, our non-turbo DOHC motor produced 259 HP and 247lbs of torque.

Hard to believe with only the stroker kit

The Turbo produced 320HP and 315 lbs of Torque. Both figures were produced with only the Stroker Kit.

Again difficult to believe, that a stock car would produce 88 hp and 59 lbs/ft more with only an extra 115cc

 

[figgie]

Let me make sure I understand... You're saying that .115 liters is a big deal? That doesn't seem right to me. Granted, I haven't tried it, so my opinion is based simply on gut feeling, but how much HP/TQ can we really expect to gain from such a small increase? I wouldn't think it to be much.

Anyone care to throw some numbers up and call me a moron? I'd love to be wrong about this!

yes it does. not so much so because of the displacement increase. Because of the stroke increase more so (+6.5mm increase). I have been running this engine. Adjuster runs this also. Gut feeling, i don't play gut feelings. But luckily I don't smoke up my tires either as the ECU takes care of that side of things.

So which is it 665cc or 115cc???

why don't you go look up a simple displacement calculator and have that answered for you

Hard to believe with only the stroker kit

Nah, see answer below.

Again difficult to believe, that a stock car would produce 88 hp and 59 lbs/ft more with only an extra 115cc

Why not ye of little science?



Displacement is not king Stroke is. Simple physics really. leverage point is further out from center of rotation (notice that I did not mention displacement ). That in and by itself has the effect of increasing torque at every instance during the power producing cycle without changing anything save for increasing fuel to adjust for the added displacement which is . Damn it where is defaint with his monster 100mm stroke engine!!

 

[7MGTEsup]

I'll take your word for it, on other cars I have seen with a stroker kit the gains have been much more modest.

 

[figgie]

I'll take your word for it, on other cars I have seen with a stroker kit the gains have been much more modest.

perhaps.

Though if I were to do it again. toyota V8 and turbo that

 

[Neodeuccio]

yes it does. not so much so because of the displacement increase. Because of the stroke increase more so (+6.5mm increase).

...


Displacement is not king Stroke is. Simple physics really. leverage point is further out from center of rotation (notice that I did not mention displacement ). That in and by itself has the effect of increasing torque at every instance during the power producing cycle without changing anything save for increasing fuel to adjust for the added displacement which is . Damn it where is defaint with his monster 100mm stroke engine!!

So one could then theorize that there are decent gains to be made by simple stroking the engine without having the bore increased. This is something I'll need to think about...

 

[figgie]

So one could then theorize that there are decent gains to be made by simple stroking the engine without having the bore increased. This is something I'll need to think about...

well think of all the little i4 that have 97mm strokes stock or even more. Same 1.8L engines but making more power (scion for instance).

 

[Neodeuccio]

well think of all the little i4 that have 97mm strokes stock or even more. Same 1.8L engines but making more power (scion for instance).

Now, this is probably going to sound dumb to some of the more experienced members, but is a new crank needed to do a stroke job? Or is it just a matter of changing the rods? I'd be inclined to replace all the internals at the same time, but if the crank is the same, it should be possible to save a few bucks...

 

[figgie]

Now, this is probably going to sound dumb to some of the more experienced members, but is a new crank needed to do a stroke job? Or is it just a matter of changing the rods? I'd be inclined to replace all the internals at the same time, but if the crank is the same, it should be possible to save a few bucks...

need new crank

stroke is a primary funtion of the crank. IE how far away is the rod mains from the center of rotation. Rod only affect the rod ratio.

 

[Neodeuccio]

Got it. So basically, whenever I get around to doing an engine rebuild, I need to get a new crank, rods, pistons, rings, turbo, exhaust mani, intake, intercooler... Boy that's going to get expensive. I might as well throw in a new kitchen sink while I'm at it.

 

[Keros]

ps the stroker kits make the rod 6 inches in length instead of the 5.8 inches for stock.

Referencing to Supracentral's post about stroked motors:

http://www.supramania.com/forums/showpost.php?p=180719&postcount=18

The industry "rules of thumb" for mean piston speed are:

Under 3,500 ft/min = Good reliability
3,500-4,000 ft/min = Stressful, needs good design
Over 4,000 ft/min = Very short life

Stroke and RPM are really all you need to know.

The formula is Cm = 0.167 x L x N

Cm = mean piston speed in ft/min
L = stroke in inches
N = crankshaft speed in rpm

Take the stock 7M-GTE with a 3.582" stroke and a 6500 redline.

At 6500 RPM your stock motor has a Mean Piston Speed of 3880 ft/min. Based upon our chart above, you are already "pushing" it in stock trim.

The stroker kit linked earlier from Import Performance Parts adds 6.5mm of stroke, .255", which is overall 3.837" of stroke and 4165ft/s mean piston speed at 6500rpm. figgie mentioned something about an 8500rpm redline, which with the stroker kit is almost 5500ft/s mean piston speed.

That's something to think about if one were to want the engine to last. If longevity and reliability aren't a concern, then disregard this post. However, blowing a piston through your hood is a good excuse to buy a carbon fiber hood :icon_razz

 

[figgie]

Referencing to Supracentral's post about stroked motors:

http://www.supramania.com/forums/showpost.php?p=180719&postcount=18



The stroker kit linked earlier from Import Performance Parts adds 6.5mm of stroke, .255", which is overall 3.837" of stroke and 4165ft/s mean piston speed at 6500rpm. figgie mentioned something about an 8500rpm redline, which with the stroker kit is almost 5500ft/s mean piston speed.

That's something to think about if one were to want the engine to last. If longevity and reliability aren't a concern, then disregard this post. However, blowing a piston through your hood is a good excuse to buy a carbon fiber hood :icon_razz

well aware of Mike's post
2 years 20k+ miles with no piston popping up. And believe me I don't baby cars (mileage or otherwise just maintanance).

 

[bigaaron]

need new crank

stroke is a primary funtion of the crank. IE how far away is the rod mains from the center of rotation. Rod only affect the rod ratio.

You can have a stock crank modified for more stroke. The rod journals are welded, then ground off center, then welded again and ground, then repeat until it's at the stroke you want. It is a time consuming process and it is not cheap. Depending on which way the journals are moved you can create more or less stroke. That is why a core deposit is required with most 7m stroker kits, they are using stock cranks.

 

[tekdeus]

In comparison, when I hear of the 2J 3.4L stroker kit, that extra 0.4 seems much more significant.

 

[figgie]

In comparison, when I hear of the 2J 3.4L stroker kit, that extra 0.4 seems much more significant.

want to know the stroke of the 3.4l 2jz? hehe