[Bubba3200]

I see the 4.6, 4.7, strokers and even heard of a 5.0 stroker from the 4.0. 5.0 being 300 hp. You hear of engines like the guy who jumped the Subaru over the water on New Years Eve....he had a 4 banger with 400 hp. 100 hp from each cylinder. I know he just had to use that engine to jump and not real world (Stop & go traffic etc) so maybe his 4 banger 400 hp would not be very reliable. Just how much reliable hp can you get out of the 4.0. I hear that 5.0 from a 4.0 is about max for reliable power. Couldnt you get 100 hp from each cylinder from the inline six?

[Unlimited04]

Originally Posted by Bubba3200

Couldnt you get 100 hp from each cylinder from the inline six?

with enough money anything is possible.

[PlaySmart]

You could probably get 7,000HP, given you have, money, know how, money, and did I mention money?

Nitrometh, forced induction out the ***, stronger and custom everything......

[wrangler2007]

One thing you need to do is look at a QUALITY forged rotating assembly, cnc the head and have it over-bored, intake work, and look at some type of forced induction. IF you want more look at a meth injection kit. About all you could do without some SERIOUS cash flow into this motor...but if you have big power goals you might want to look at getting a v-8...

[Greg_Volkman]

Originally Posted by Bubba3200

like the guy who jumped the Subaru over the water on New Years Eve....he had a 4 banger with 400 hp. 100 hp from each cylinder.

Apples to oranges... a subaru WRX STi comes with close to 400hp from the factory...it's engineered to produce the horsepower.

Your I-6, on the other hand, is engineered for low-end torque. It's not built to rev high. I am sure some company out there could make their own flow-through heads...maybe add valves or something...but by the time they were done it wouldn't resemble anything stock and it'd cost a pretty penny.

at that point, why not just drop an LS1 in or something similar?

[GreenLanternXJ]

JP or Peterson's (I can't remember which) did an article where they got ridiculous hp from the 4.0. However, it cost a ton

[wrangler2007]

Originally Posted by Greg_Volkman

Apples to oranges... a subaru WRX STi comes with close to 400hp from the factory...it's engineered to produce the horsepower.

One thing too I forgot to mention was that the STI's have 300 crank horsepower. That 400hp you talk about I believe was measured at the wheels on their race car. Those motors are near their breaking point on the stock rotating assembly. I'm sure that they don't really put the drivability and every day use factor into modding that engine. It's a sponsored race car...break the engine and they can throw another one right in with the same specs. They don't have to live with it daily. What I'm trying to say is that yes you can get a lot of hp out of a motor, but to do it efficiently where you can drive the vehicle easily and reliably, that's where the money comes in and things get more expensive. To run that kind of hp on the street and still "have fun with it" every now and then, the owner would want a forged rotating assembly...and so will you if you want to get the most hp out of this engine.

[Greg_Volkman]

I've heard of 600hp STi's on induction...it's crazy the HP they are getting out of them.

[BYuen]

Well JP Magazine covered their "Insane Inline" in this January issue. This bad boy was stroked to 5.0 liters and turboed. When all was said and done they report a whopping 693 HP and 777 lb/ft of torque! But is this realistic for the majority of us...? Nope!

[mlo_in_lv]

schwiiiiing

[spyder6]

Originally Posted by BYuen

Well JP Magazine covered their "Insane Inline" in this January issue. This bad boy was stroked to 5.0 liters and turboed. When all was said and done they report a whopping 693 HP and 777 lb/ft of torque! But is this realistic for the majority of us...? Nope!

5.0L stroker, turbo, hesco head, and compression that a diesel would pay attention to

[Max-Q]

Originally Posted by Greg_Volkman

Apples to oranges... a subaru WRX STi comes with close to 400hp from the factory...it's engineered to produce the horsepower.

Your I-6, on the other hand, is engineered for low-end torque. It's not built to rev high. I am sure some company out there could make their own flow-through heads...maybe add valves or something...but by the time they were done it wouldn't resemble anything stock and it'd cost a pretty penny.

at that point, why not just drop an LS1 in or something similar?

The STi actually has 300 hp from the factory but they are rather easy to modify and increase power. I gained 50 hp and 87 lb/ft torque at the wheels with just a dyno tune.

To the OP- An engine such as the EJ25 from the STi or the 4G63 2.0L engine from a Mitsubishi Evo IX are far different from your Jeep 4.0L engine. These engines are ultra high performance engines capable of high compression. They use the most modern technology for nearly every part to increase power. For example, the STi is an all aluminum engine with multiple valves per cylinder and multiple camshafts. The computers are able to optimize timing and camshaft positions to maximize power throughout the RPM range. The STi even has sodium filled exhaust valves to better withstand the heat. The Evo has hollowed cams to make them lighter. Both cars use turbos that even in stock form would destroy your 4.0 engine. The VF39 turbo in my STi was tuned to produce 19 lbs of boost on 93 octane gas and the turbo on my Evo would boost to 26 lbs on pump gas.

You would have to do a ton of work and spend an incredible amount of money to make a 4.0L engine into something comparable to an STi or Evo engine. The only real way to produce that kind of HP from the 4.0 is by increasing displacement and opening up the heads to allow them to breath better and installing a cam with the proper lift and duration depending on the engine, pistons, compression and tune.

[rubidriver]

Originally Posted by wrangler2007

One thing too I forgot to mention was that the STI's have 300 crank horsepower. That 400hp you talk about I believe was measured at the wheels. Those motors are near their breaking point on the stock rotating assembly. I'm sure that they don't really put the drivability and every day use factor into modding that engine. It's a sponsored race car...break the engine and they can throw another one right in with the same specs. They don't have to live with it daily. What I'm trying to say is that yes you can get a lot of hp out of a motor, but to do it efficiently where you can drive the vehicle easily and reliably, that's where the money comes in and things get more expensive. To run that kind of hp on the street and still "have fun with it" every now and then, the owner would want a forged rotating assembly...and so will you if you want to get the most hp out of this engine.

You have your numbers mixed up. Crank HP is always more than rear wheel HP.

[Max-Q]

Originally Posted by rubidriver

You have your numbers mixed up. Crank HP is always more than rear wheel HP.

Yep, on average you can figure about a 20% drivetrain loss, especially in an AWD car such as the STi. For example, my STi had 300 hp at the crank. On a dyno in pure stock form it was around 236 hp at the wheels which is slightly higher than a 20% loss. After adding a 3" downpipe, high flow cat and a 3" midpipe it went to 254 hp and 255 lb/ft torque at the wheels. Then with a dyno tune it jumped to 304 hp at the wheels and 342 lb/ft torque at the wheels. That would equate to about 365 hp at the crank but to be honest, once you start modifying cars and tuning them nobody ever talks about crank power. It's all about wheel hp after that.

BTW- did I mention my CTS-V makes nearly 500 hp at the wheels?

[rs4race]

haha yep. hp cost money.

I had a 2.0 4 cylinder pushing a smidgen over 400hp. Thats 200hp per liter, which is pretty good. It was pretty reliable actually it was my daily driver for several years. I put alot of money into the motor however... I would say around 8000 in engine and driveline mods..