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Mods leading up to stroker later on.

Cburb88XJ

Cburb88XJ

NAXJA Forum User
Location
Purcellville, VA
I'm slowly doing mods to my jeep to get a little more power since it keeps gaining weight and I need to pull a utility trailer around every now and then. Trying to do some mods for more power now while leading up to what I need to have for a stroker in the first place.

So far k&n drop in filter, 2 different headers just installed oem with flex joints, MagnaFlow cat, 44 muffler. In the middle of installing 99 intake with the ev6 oem injectors,63 mm TB, hesco regulator after that's done I'm going to see how it performs and I think the next step for power would be a cam kit but If possible I'd like the cam to work ok later if I stroked it.

Hopefully I can do that, I'd like to have the majority of things you need for a stroker done already and if I'm not satisfied I could stroke it and my engine would already have the other necessary bits done. Not after a racing engine just something that pulls strong. Any help on this would be good if this seems like a decent idea or not. Little easier on money and time doing it this way anyways.
 
I'm new at all this engine stuff. All I can say is I would go looks at this link.

http://jeep4.0performance.4mg.com/stroker.html

Also read up over at www.jeepstrokers.com

There is a lot of cam info over there.

The main decision I see is that you need to go ahead and build you stroker before you actually build it. Decide everything from what crank, rod, pistons, head gasket, etc you want to use now so that when the build starts, you have a cam that will work with that combination of parts. It seems like subtle changes can affect how the engine will perform.
 
Cooling system upgrades.

Flowmaster mufflers also don't flow very well. If you are planning a stroker I would go with 2.5" exhaust and maybe a straight through muffler like a Magnaflow or a turbo muffler like Dynomax.
 
I wouldn't bother with internals upgrades that you plan to move to a new motor later. A cam isn't all that expensive, and any quality builder (yourself included) should replace it again at that time anyways..


Most of the rest of the upgrades you mentioned won't really benefit a stock motor. A header, good exhaust, an intake.

Don't waste your time doing a bored throttle body, injectors, etc. Your engine can't take advantage of it, so you're just burning time and gaskets for nothing. Buy the parts, put them in a closet and start saving for the next piece of your stroker.
 
This might disagree with Cal, but here goes. There are a total of 5 things I've found that in combination wake up a stock motor to the the most a stock motor can provide - High Flow air intake, high flow exhaust, 99+ intake, 60mm throttle body, and an air/oil separator. That's it. Total cost is pretty low and you can put the rest of the money into stroker parts.

A 4.0 motor cannot draw any more air in than a 60mm throttle body will provide and 60mm TB's are inexpensive since they just machine the stock ones. And no machining of the intake is required.
 
Yes I would disagree. ;)

A cam does a lot for a stock motor, but there's no point in doing it if you plan on changing the motor.

And the stock 4.0 won't breath more air than a stock throttle body flows. it does get more 'seat of the pants' feel because you're giving it more air for the same throttle, but you'll get the same response by pushing the throttle a little harder, and the same output at WOT either way.
 
SolarBell said:
There are a total of 5 things I've found that in combination wake up a stock motor to the the most a stock motor can provide ........... and an air/oil separator.
Click to expand...

How does an air/oil separator help produce more power?
Is this for an older engine with blow-by?
I see then on turbo and supercharged engines but not on naturally aspirated engines.
 
Because on the 4.0 the intake is always pulling air from the valve cover to evacuate potential buildup of fuel vapors and exhaust gases (CCV). But that air always includes small particles of oil entrained in the air from the oil splashing around the valves. That oiled air gets pulled into the intake and into the cylinders and reduces the effectiveness of the fuel since oil doesn't burn particularly well. It's equivalent to getting a grade or two of better fuel.

To be honest - I put one on not expecting anything since I was just prepping for the supercharger so I thought it was crap myself. But I ended up noticing an improvement in power and fuel economy. My motor has less than 60k miles with great compression, but I still pull out about 1/2 - 3/4 a teaspoon of oil every tank of fuel.

YMMV. I could be an edge case or completely off my rocker. It's happened before.
 
Yea I don't agree with that. I have literally seen dyno results of the 99 intake, bored tb, ev6 higher lb injectors and hesco regulator. I can do the build myself I wouldn't be getting a brand new engine or sending it off. I was more or less curious if I can buy a cam kit for right now that would also work ok for if I were to stroke it later on. This engine has like 154k on it and the comp were 160s last I checked.

I highly doubt you could do all these mods to the 4.0 and gain no benefit that has been proved many times and I've seen a few dynos enough to convince me.
 
cal said:
And the stock 4.0 won't breath more air than a stock throttle body flows. it does get more 'seat of the pants' feel because you're giving it more air for the same throttle, but you'll get the same response by pushing the throttle a little harder, and the same output at WOT either way.
Click to expand...

:clap:

SolarBell said:
Because on the 4.0 the intake is always pulling air from the valve cover to evacuate potential buildup of fuel vapors and exhaust gases (CCV). But that air always includes small particles of oil entrained in the air from the oil splashing around the valves. That oiled air gets pulled into the intake and into the cylinders and reduces the effectiveness of the fuel since oil doesn't burn particularly well. It's equivalent to getting a grade or two of better fuel.
Click to expand...

The 4.0 is a very knock proof motor in stock form, I added 5* of timing throughout the fuel map and even on crappy 87 octane CA fuel I hardly see any knock what so ever. If you were getting enough blow by to have oil vapor cause pinging on a stock timing map I could see where the oil separator would be helpful. Even with 210k on the clock my motor doesn't have enough blow by/oil vapr to cause pinging on a tune with lots of timing, even with the hell me and the previous owners have put it through.
 
Last edited:
You can doubt it all day long, you'll still be wrong. Without changing the cam or displacement, those mod's aren't going to change your dyno horsepower at all. Do a header and exjuast, gain a couple hp and few pounds of torque, but the rest of that is a placebo on a stock motor.

Yes you can do a cam, but almost any cam worth doing is going to require different valve springs, which aren't going to be bolt on (the only bolt on optoin is now discotinued) so you're doing a valve job and custom spring setup, usually with chevy LS stuff, and new valves.

At that point you might as well finish your stroker.
 
So what you're saying then is adding a 99 horseshoe intake, 63 mm tb, hesco adjustable regulator, and 24 lb ev6 injectors will make no difference at regardless of the data that is out there.
 
It will add no additional horsepower to an otherwise stock motor, no. The engine simply can't use the extra air or fuel.

What will happen is it will jump off of the line just a little faster because you're giving it more air and fuel at 25% throttle than it used to get, but instead of increasing in power to say, 100% or throttle (closer to 80%) it will peak out at 80% throttle (closer to 65%).

It will feel like more to your ass, but the dyno will call say otherwise.
 
Go read that thread again.

he's starting with a built motor. Port and polished head, chevy big valves, etc..
 
The only difference is ported and ls1 valves. Just that done alone all the sudden makes the mods worth while but a stock h.o. head won't have any gains with this? I'm not buying it...regardless I plan on building up a head later on anyways I have a spare head for when I go this route.
 
cal said:
Yes you can do a cam, but almost any cam worth doing is going to require different valve springs
Click to expand...

I can say I found this out. Put a mild cam in mine because I got it super cheap and the motor was already on an engine stand. Slight increase in power to say the least. I would have been disappointed if I had gone through the trouble of installing it in the jeep. I did other crap too like a header and injectors to help but in the end it didn't matter, climbing grades still sucks.

So now I vote stroker or nothing
 
Cburb88XJ said:
The only difference is ported and ls1 valves. Just that done alone all the sudden makes the mods worth while but a stock h.o. head won't have any gains with this? I'm not buying it...regardless I plan on building up a head later on anyways I have a spare head for when I go this route.
Click to expand...

Go ahead and do it. I'm not saying don't do what will make you happy, I'm saying that you will gain no power from it.

I'm not speaking from what someone else claims on the internet, but actual experience in a real world over the last 12 years, 6 XJ's, and 5 stroker motors.

Do your mods. Then come drag race. ;)

I'll even throw down pinks......
 
Cal and I may disagree on the options, but he's right. The displacement isn't changing. It's throwing money at getting rid of other restrictions that may or may not exist in the system. Some are valid restrictions and will regain you what shouldn't have been lost in the first place, some just change how you feel about it.

For example, the pre-99 log intake is bad enough that when Jeep had to try to make up the 5HP they lost with the new emissions equipment. They made that back up by replacing the loss-inducing intake with the 99+ intake which gets rid of the losses to make the 5HP back up.

Keep in mind you can never get past the 4.0 liters that exist in the engine. It's a terminal proposition without changing the displacement.
 
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