What numbers could i get out of a built 4.0 OHV

[Downey]

i head that putting 98 style heads on my 94 block will bumper my compression to 10.1. is that true?


bird do you have any threads on your motor builds.

 

[Bird]

i head that putting 98 style heads on my 94 block will bumper my compression to 10.1. is that true?


bird do you have any threads on your motor builds.

95+heads will bump your compression also - the 98+ have small exhaust ports that will restrict flow until ported more heavily that the 95-97 heads.

No threads left out there that I can find, but I've already given you the recipe.

Bird

 

[pfar54]

From what Bird is saying it looks like you will be spending a whole bunch of money for in my opinion not much power at all... a few grand just for 250hp? Buy a new vehicle if you want something fast.

If you want something though do gears. That is the best bang for the buck in just about any RWD vehicle. It will feel like you've actually gained power, when in fact you may lose 1-2 hp with the lower gear.

Oh yea and to everyone who keeps saying for any high hp car you need to rev to a crazy number like 8-9k not even close to true. It depends on lots of things like the kind of cam you have, your tune, how much torque you have, power adder, etc.

My car at the moment has 490 rhp. It only revs to 6 grand. Now it is turbo'd though, so it's not as high of an rpm as an n/a car, but still. Having 540 ft/lbs of torque really helps.

Now my friend who has a built trans am he is n/a and he only revs to around 7thousand rpm's I believe. He has about the same power as me, maybe a bit more, I forget off hand.

 

[AllanD]

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

You keep asking about numbers, you seem irrationally fixated on it.

The 4.0 is pretty well optimized for offroad and towing performance as-is.
IF you want to improve upon it you are going to need a different engine.


Look at the 4.0SOHC which raises the bar from 160hp up to 207hp, but look at the penalty in low end torque.

the 4.0OHV makes 200ft/lb right off idle, the 207hp makes more torque at it's
torque peak and more torque through the upper powerband.
But it's not making 200ft/lb at 1050rpm

Now look at the next engine people look to for "bigger numbers"
is a 5.0, and generally think like hot rodders and look for a 5.0HO...

Well the 5.0HO doesn't make it's peak torque until 3400rpm!

Why are the numbers so damned important?

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[Fx4wannabe01]

Take it from someone who owns one, SOHC's suck down low. Makes me wish I went '00 for the pushrods...

 

[Ranger#1]

Take it from someone who owns one, SOHC's suck down low. Makes me wish I went '00 for the pushrods...

you guys dont even know what 4 hi is u just go for 4 lo lol iv noticed that in my friends sohc in 4 hi in the sand it sucks

 

[AllanD]

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

I'd actually be inclined to do it the other way around, put the early large chamber heads on a late shortblock and intentionally reduce compression to make the engine more boost tolerant with the blower on pump gas.

The rub is how much torque it takes to SNAP OFF the 5sp output shaft.
I've already done that without the blower.

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[exbass94]

Look at the 4.0SOHC which raises the bar from 160hp up to 207hp, but look at the penalty in low end torque.

WHAT penalty in low end torque? You mean the ~5 ft-lbs below 1600 rpm? Big freakin deal.

the 4.0OHV makes 200ft/lb right off idle, the 207hp makes more torque at it's
torque peak and more torque through the upper powerband.
But it's not making 200ft/lb at 1050rpm

You're right that the SOHC is making more torque in the upper powerband, but it's ALSO making more torque than the OHV anywhere above 1600 rpm.

Take it from someone who owns one, SOHC's suck down low. Makes me wish I went '00 for the pushrods...

I own one too, and I don't know what you're talking about. In fact, I have both a OHV and SOHC, and the SOHC kicks the OHV's ass.

 

[Bird]

I'd actually be inclined to do it the other way around, put the early large chamber heads on a late shortblock and intentionally reduce compression to make the engine more boost tolerant with the blower on pump gas.

The rub is how much torque it takes to SNAP OFF the 5sp output shaft.
I've already done that without the blower.

AD

Never had a problem with that combination on 93 octane at sea level - would work fine at your altitude.

I've seen a built 4.0 with a 125 shot of N2O run well over 100 1/4mi. passes, lifting a front tire on launch with a stock 5 speed tranny - never had a problem with the output shaft.

My own supercharged combo made untold number of passes down the 1/4 also with the factory 5 speed, t-bars and sticky tires - only broke a fork speedshifting - maybe yours was a fluke ??????

Bird

 

[AllanD]

Anything is possible but I'd love to show you the pieces...

It's just I can't get the spiral cracks radiating from every other spline root
to show up in a PIC

Breaking one makes me a bit more cautious.



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[Bird]

Anything is possible but I'd love to show you the pieces...

It's just I can't get the spiral cracks radiating from every other spline root
to show up in a PIC

Breaking one makes me a bit more cautious.

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Definitely will keep that in mind should I ever decide to hotrod one again.

You should take a vacation to come see the Alamo someday - if you do, bring your trailer and you can take a bunch of stuff back with you out of my garage........

Might even bump up the power level to be able to tow everything back........
Bird

 

[AllanD]

Definitely will keep that in mind should I ever decide to hotrod one again.

You should take a vacation to come see the Alamo someday - if you do, bring your trailer and you can take a bunch of stuff back with you out of my garage........

Might even bump up the power level to be able to tow everything back........
Bird

As I demonstrated to a friend last July, even with my truck packed with car parts and towing another ranger (a 3.0 5sp 2wd Gen2) similarly stuffed, on a tow dolly I could still easily out accelerate the truck he was driving...
a 2wd 2.3 5sp shortbox truck and his only cargo was a 4.0 engine
in his bed...

I could simply walk away from him any time I wanted to...

Funny thing was I still got nearly 16mpg while doing it with
the A/C on full blast

It's stuff like that makes me ask why anyone needs more than a properly tuned 4.0OHV?

Torque, it's what moves things.

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