You 4.0 guys have been barking up the wrong tree.

[Jeep Driver]

Or so it seems to me. 

 

Holley TBI and a distributor based electronic ignition. 

 

 

 

[Pete M]

I love it  

[Limeyjeeper]

That is some serious power. I have done several strokers and even with a ported head never got much above 270hp. Looks like the Jeep FI system really holds this engine back.

[JMO413]

That is a thing of beauty! 

[Jeep Driver]

10 minutes ago, Limeyjeeper said:

. Looks like the Jeep FI system really holds this engine back.

 

Stock MPI/ECU is trash...........pure trash. 

 

Engine still has its limitations...........however...........still has me thinking or reconsidering SBC, I've got time to think. 

 

[johnj92131]

2 minutes ago, Jeep Driver said:

 

Stock MPI/ECU is trash...........pure trash. 

 

Engine still has its limitations...........however...........still has me thinking or reconsidering SBC, I've got time to think. 

 

Stock efi system is not trash! It is purpose built to provide a smooth running long term engine that meets legal requirements for it's required life span.

All aluminum Chevrolet engine, built years after the Jeep 4.0 offer many advantages.

 

[MJXJjeepguy]

1 minute ago, johnj92131 said:

Stock efi system is not trash! It is purpose built to provide a smooth running long term engine that meets legal requirements for it's required life span.

All aluminum Chevrolet engine, built years after the Jeep 4.0 offer many advantages.

 

Amen. 

[johnj92131]

16 hours ago, Jeep Driver said:

Or so it seems to me. 

 

Holley TBI and a distributor based electronic ignition. 

 

 

 

Years ago I got an offset ground 258 crankshaft on eBay for this guy.  Honda rod journals and a set of forged Chevy rods with Honda size rod journals.  Stroke was about 4.10 inches. So depending on the overbore, displacement could be in the 4.85 to 5.0 range.

Extrapolate his very flat torque curve, and you could see a great engine.

But no way to pass California smog tests. A strick legal requirement.

My grandson now has the crank and rods. So perhaps this equipment may be put to use.

 

Still, a California smog legal Chevy aluminum V8 conversion sounds potential better.

 

That said, just buying a late model pick up would seem to be a more reasonable choice.

[Jeep Driver]

40 minutes ago, johnj92131 said:

Stock efi system is not trash! It is purpose built to provide a smooth running long term engine that meets legal requirements for it's required life span.

All aluminum Chevrolet engine, built years after the Jeep 4.0 offer many advantages.

 

 

You are stuck in a box, a California box, it clouds your thinking. 

 

I'm not stuck in a box, refuse to be stuck in a box. 

 

For those who want more, stock system has nothing to offer, nothing, no controllability, no tuning.   

 

 

 And no, I don't want to climb into the LS box with everyone else. 

[DirtyComanche]

Meh.  Just another stroker.

 

But that Offenhauser intake is worthwhile.  I had one on my 4.0L when I ran propane.  It does flow well right out of the box, and obviously it could easily be improved.  The big plus then is you really could cram some air into it, because if you look at any other modern engine in the 4-6L displacement range you're going to see the intake/TB is absolutely massive in comparison with even the bored out HO TB.  I personally believe the throttle body and intake design is a huge hindrance on these engines, with them having made some incremental improvements over the years but never actually getting it right.  IMHO you could probably make more power by running the TB on it's side too, pointing towards the runners/head, and thus eliminating the bottle neck of the hard 90 degree turn right after the TB, but you'd probably have to fab an entire intake manifold for that.

 

And yes, you are right, running the stock ECM is going to limit you.  That's why many guys go to mega/microsquirt, although I think it's pretty much an abomination in most forms.  Throwing a Sniper on the Offy intake would be a dead nuts simple solution for many people, but it is leaving power and economy on the table versus a properly tuned MPFI setup.

[Eagle]

46 minutes ago, johnj92131 said:

That said, just buying a late model pick up would seem to be a more reasonable choice.

 

Yeah, but what fun is that? Sanity is overrated.

[johnj92131]

On 8/25/2019 at 11:09 AM, Eagle said:

 

Yeah, but what fun is that? Sanity is overrated.

 

Eagle, you are very close to the truth.  But with 4 project/toy cars, I do need  one that I can depend on every day.  So I dumped my old VW Passat TDI that VW had discontinued all most all parts support for a 2018 Chevrolet Volt in August, 2018 for a $254/month lease.  Then Guess what?  GM ended the Volt 6 months later.  Have to say that the $254/mo lease is considerably less than my maintenance  cost for the Passat TDI

 

And, while maybe not fun, it is sure nice to pay less than a dime per mile on a new car when I drive on the battery..  My Comanche TDI still needs to get the A/C working to be a decent daily driver. Even then it will cost more per mile than the Volt, just for fuel. 

 

On long trips, the Volt gets 40-45 mpg, just about the same as the old Passat (yes, my speed is lower).

[schardein]

On 8/25/2019 at 12:43 PM, Jeep Driver said:

And no, I don't want to climb into the LS box with everyone else. 

There is a reason everyone is jumping in that box.  Not following the crowd so as to be different, doesn't mean the crowd is wrong.

 

I pulled the 4.0HO from my CJ7 to put in a 5.3 LM7.  I expected a lot, but results still exceeded my expectations.

 

I have a 1980 CJ5 that I intended to put the 4.0HO in.  After all, it had been in the CJ7 for 16 years, all issues had been sorted out in the first year and had proven reliable.  Instead, I have another 5.3 sitting in the workshop now.

[ftpiercecracker1]

So this is what I'm hearing. For capturing the most power this is the breakdown.

 

Most to Least: 

 

Complete, stand alone, engine management 

Megasquirt or the like

 

Carb

 

Stock EFI (HO or Renix?)

 

 

I always thought that replacing the EFI with a carb was bass ackwards? I thought you would lose power? Is this correct? On a stock engine with all other things being equal and not being concerned about efficiency/mpg. 

[gogmorgo]

Going to a carb is a step backwards technologically, sure. But if you know what you're doing, you can get them tuned to be competitive with fuel injection in most situations.

The advantage of fuel injection is the ability to react to changes in running environment. You've got all the basic sensors to read the data, and then the only increased complexity is in the programming. With a carb, you need some fairly complex mechanical systems to accomplish the same, and then there will always be a small delay between fuel entering the intake and entering the engine, so the carb is always slightly behind in responding to changing conditions at least in comparison to port injection.

Looking at factory carb setups, it'll be similar to efi systems in that cheap and reliable are the primary concerns. They're tuned to run good under most circumstances and okay everywhere else. Going into the performance aftermarket though you'll have carbs that will outperform a stock efi setup, that are tuned to run great, but because they're so highly optimized, you may need to make manual adjustments over the course of the day, or even change out jets, to keep them in that sweet spot due to changes in ambient air temperature, pressure, and humidity. In contrast a highly optimized efi system can make those adjustments on its own, or else it's a couple keystrokes on a laptop instead of pulling out wrenches. 

 

So, would you lose power? Depends. If you bang on a carb off an old 258, definitely. If you go down to your local hotrod shop and dump your wallet out, then take it down to your local dyno shop and hand them the rest of your wallet, you'll probably get something that performs much better. Possibly better even than the factory efi.

But as has been pointed out, the factory efi is tuned for reliability and cost of manufacture, not to extract absolutely everything possible from the engine.

[Jeep Driver]

Jeeezzzzzzzzzz, come on now. 

Carb was used for dyno testing only, narrator clearly stated that owner intended to use TBI.

 

Here, TBI-

 

 

[Jeep Driver]

On 8/27/2019 at 8:32 AM, schardein said:

There is a reason everyone is jumping in that box.  Not following the crowd so as to be different, doesn't mean the crowd is wrong.

 

I pulled the 4.0HO from my CJ7 to put in a 5.3 LM7.  I expected a lot, but results still exceeded my expectations.

 

I have a 1980 CJ5 that I intended to put the 4.0HO in.  After all, it had been in the CJ7 for 16 years, all issues had been sorted out in the first year and had proven reliable.  Instead, I have another 5.3 sitting in the workshop now.

 

 

 

Nostalgia.