What numbers could i get out of a built 4.0 OHV

[Downey]

So if i would build an 4.0 ohv. what the most hp and tq i could get of the motor? what would need to be done to get to this point?


Thank

Cam

 

[Big Jim M]

Well there is built and then there is built! Too get the most HP and torque out of the engine you would have to run it above 5,000 rpm.. If you intend to run it on the street it wouldn't pull a fat girl off of a potty!

However if you intend to run it on the street all you would need is a low rpm, stump pulling, cam and you would be in business.

What most of us fail to see is how many rpm we actually USE. We need a camshaft that produces for us at two grand..not at six grand.

It is possible to build a very stock engine with the proper camshaft and have the best of all worlds. First it would be cheap to build. Then it would be driveable..

It would be nice to have one of those 9,000 rpm NASCAR engines in our rides... but below 6,000 it wouldn't hardly run.

So building is a compromise.. what is it you want your ride to do?
Big JIm

 

[Downey]

i want stomp pulling low end for off roading and some mild towing. i just want a good all around motor gas mileage isnt a concern i only drive my truck maybe one day a week and less than 100 miles

 

[Big Jim M]

i want stomp pulling low end for off roading and some mild towing. i just want a good all around motor gas mileage isnt a concern i only drive my truck maybe one day a week and less than 100 miles

Then change the differencial gears and leave the engine alone.. Those gears will give you all the stump pulling you can use.. Go as low as you wish.
Big JIm

 

[Downey]

not the real answer to my question i want something a little over stock. but i have no idea what number i could pull i would love to make 250 rwhp. but i have no idea what it would take

 

[fastpakr]

The ONLY way you're going to get 250rwhp from an OHV 4.0 without destroying bottom end power is through forced air or nitrous. Power modifications for an N/A engine will move the torque peak upwards on the RPM scale. You seem to want it to move downwards and increase power at the same time - not possible with normal aspiration and pump gas.

 

[Downey]

lets just say this. what numbers could i get with out na motor? what would i have to do?

 

[fastpakr]

Can you punctuate that sentence? I'm not sure what you're asking.

 

[Downey]

fixed sry lol

 

[Fx4wannabe01]

http://www.rangerpowersports.com/forum/member.php?u=35757

He's got just about all you can do to it in NA form.





still ain't fixed or makes sense...

 

[Downey]

i dont get what your trying to show me with that link shane. and my question above is what can i get out of a NA motor and what do i have to get the most out of it

 

[Big Jim M]

Downy What you want is doable to some extent.. BUT you won't be able to drive it where you are driving it now. Changing the horsepower requires more rpm to get that horsepower.. All the while losing horses where you drive the vehicle now.
So in the end you will wind up changing axle gearing to get into the higher rpm..

So the answer is to change the axle gearing and see what your present engine does..

NASCAR engines have 850 horsepower! But they get that horsepower at OVER 9,000 rpm. YOU and I are looking for a few more horses at 2,000 rpm. So we can drive our vehicles at normal speed and normal places...not just on a track in circles.

You could build up the super most exotic 4.0 engine imaginable.. and it wouldn't pull a fat girl off of a potty...until it gets above 4,000 rpm.

I have many friends that have built up their engines for the most horsepower.. They are for the most part sorry they did so. Their rides hardly move in traffic and offroading is a nightmare for them.

What we need is a smooth idle and power from 1200 to 3,000 rpm. That is what makes an engine drivable. High rpm horsepower doesn't.

Big JIm

 

[Fx4wannabe01]

^^This man speaks the truth. You OHV guys got it good...must be nice to have SOME torque down low... SOHC's SUCK in the down low RPM's.



Downey.... that is a profile link. You go to the profile, and see the threads he's posted to learn OHV engine mods because as I said in my post, he's got just about all you can do to a OHV on his in NA form. Maybe he'll have power numbers? All about searchin' and learnin'...

He may be a member here, i don't know.

 

[Downey]

alright thats what i thought shane just didnt look to deep at first

 

[Bird]

pre-95 pistons with 98 style heads for a 1 point bump in compression, p&p heads with SI-Valves undercut stem valves, 410 cam, headers+ 2.5 exhaust system = 200+ rwhp with excellent torque characteristics for 4 wheelin.

Anyone tells you different = they haven't built one like this - I have.

Use P&P pre-95 heads for factory compression ratio and add a Paxton Kit with 5# boost = 260+rwhp with enough torque to shred the tires off that thing. (yep - done that also)

Bird