HP gains from stroked 4.0?

Performance mods and Advanced Stroker discussion.

HP gains from stroked 4.0?

Postby dwg86 » March 11th, 2010, 12:35 pm

What is keeping the Jeep stroker from putting out bigger Hp numbers. The new Chevy 3.6 V6 that is being installed in the Camaro is putting out 304HP 273ft/lb torque and the new Mustang 3.7 V6 is putting out 305hp and 280ft/lb of torque(torque numbers are a bit lower than I would want). I know these are new designed engines with new technology, but I have seen some old technology, pushrod, 302 fords put down some big hp/torque numbers.

I just thinking WOW! a 3.6 with 304hp, and gets 29MPG?

Now I haven't dynoed my stroker, but with all the time spent porting the heads, as well as all the other performance upgrades (roller rockers, bigger T/B, bigger cam, larger injectors) I don't think I would have more than what...260-270hp???

My next stoker I am thinking about building will have a 4.000 inch stroke and ???? size bore. Let's just say it was a 4.00 inch stroke with a 4.00 inch bore and used a 6.000 inch rod, that would be a 302 cid, with a 1.50 rod ratio. So now that is a 302 cubic inch 6 cylinder. Can you expect the same power as a 302 V8 with the same bolt ons(Cams, rockers ect)?
Is it the head design that limits the power of the engine?
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Re: HP gains from stroked 4.0?

Postby SilverXJ » March 11th, 2010, 1:06 pm

Its the engine design. Its just old. Two valves per cylinder, push rod, non cross flow head, all iron, cam dynamics, flat tappet. Plus you have to take a look into where those numbers are made. With numbers like those (low torque, high hp) they probably rev fairly high and that is where they make the power. Their torque down low is probably pretty sparse. Aren't those engine direct fuel injection as well?
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Re: HP gains from stroked 4.0?

Postby lafrad » March 11th, 2010, 1:42 pm

well, they don't need direct injection to make 300 hp from a 4.0L V6.

Our restriction is the heads. we have to do intake AND exhaust, both on ONE SIDE of the head. All those high HP V6's get one side of the head for intake, one for exhaust. you can just make things BIGGER. Spark plug in the middle helps too.

The actual block and rotating assembly means very little to actual power production.

Our cam designs also don't help... however, if you are willing to sacrifice idle quality, a flat tappet can is able to make great power.
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Re: HP gains from stroked 4.0?

Postby SilverXJ » March 11th, 2010, 2:00 pm

Direction injection and aluminum heads also mean you can run a higher compression ratio on pump gas due to the cooling effects of both. And variable valve timing also makes things better.
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Re: HP gains from stroked 4.0?

Postby Cheromaniac » March 13th, 2010, 2:30 pm

I never dyno'd my old 4.0 when it was bone stock but from the performance numbers at the time, I calculated that it was putting down 155rwhp and 198rwtq. With the 4.6 stroker and all the other external bolt-on performance enhancers, I now have 30% more HP and TQ than stock.
The Jeep stroker's biggest strength is its ability to put down monster torque from off idle to about 4500rpm, and none of those modern 300hp V6's can match that.
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202rwhp @ 4700rpm (248bhp)
258rwtq @ 3400rpm (311lbft)
1/4 mile: 14.63 @ 94.4, 3450lb curb
Stroker build-up, Stroker "recipes"
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Re: HP gains from stroked 4.0?

Postby SilverXJ » March 13th, 2010, 4:06 pm

I dyno'd mine before the stroker with a header, cat back, and cai. I got 149 hp@4600rpm and 183.47tq@ 3750rpm. If my engine actually holds together one of these days I will go back to the same dyno and get another run with the stroker. Mine is a 2000, so it would be different from Dino's. I wouldn't doubt that his made more HP stock than mine to begin with.
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