Renix vs HO

[89 MJ]

I am still looking for a motor to swap in my 89 Comanche. If I were to buy a HO Jeep as my engine donor, would you recommend swapping everything to HO? 

 

Could I use the Renix throttle body with a HO full gauge set?

[87MJTIM]

Are the instrument gauges compatible between the Renix v. HO?  Will you need to swap dash wiring also?  IDK.

[89 MJ]

3 hours ago, 87MJTIM said:

Are the instrument gauges compatible between the Renix v. HO?  Will you need to swap dash wiring also?  IDK.

This is kinda what I’m wondering. 

[Smokeyyank]

So, I know you can swap certain HO parts over without the harness.  The new project MJ I'm picking up from meanlemons he did just that. Has a 96 block with the 99 intake and a few other things from the HO but will still be renix. If you do a full HO swap 98 or 99 are the only ones I'd consider. Obd HO swap isnt worth it IMHO.

[89 MJ]

1 minute ago, Smokeyyank said:

So, I know you can swap certain HO parts over without the harness.  The new project MJ I'm picking up from meanlemons he did just that. Has a 96 block with the 99 intake and a few other things from the HO but will still be renix. If you do a full HO swap 98 or 99 are the only ones I'd consider. Obd HO swap isnt worth it IMHO.

Ok. Thanks for the input. 

[cruiser54]

CRUISER'S MOSTLY RENIX TIPS

HO INTO RENIX SWAP

OCTOBER 31, 2015 SALAD 61 COMMENTS

 

This swap is easier than some will lead you to believe. And generally Pooh-poohed by those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.

• XJ Cherokee and ZJ Grand Cherokee 4.0L engine blocks interchange.
• 2000+ TJ Wrangler and WJ Grand Cherokee 4.0L engine blocks interchange.
• YJ and 1997-1999 4.0L TJ blocks will interchange in XJ/ZJ
• XJ/ZJ blocks, and the 2000+ TJ/WJ blocks do not interchange without significant modifications.

TJ/WJ 4.0L Engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand and 2000 TJ Wrangler. These blocks are not interchangeable with XJ/ZJ engine blocks. The reason is motor mount bolt holes and belt driven accessory mounting bolt holes are in different locations, or not present at all, TJ/WJ vs. XJ/ZJ.

Now that we know which engines we can use, let’s get down to business.

The HO and Renix have some differences but none that can’t be overcome very easily.

One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from an HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head at the rear for the sender.

You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use a new Renix gasket. Exhaust ports are identical.

An alternative on exhaust manifolds:

As far as exhaust, you can use the Renix exhaust manifold and be fine.
If you want to use the HO exhaust manifold, you must go with an HO headpipe and screw your O2 sensor into that headpipe. Standard Renix harness is plenty long to do so.
A bung can be welded into the HO manifold to accept the EGR tube.

You will need to use your Renix distributor as it is different than the HO design. See Tips #12 – Setting Your 4.0 to #1 TDC and #13 – Distributor Indexing to be sure you get the distributor installed correctly.

The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.

The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16” square drive or a modified 3/8” drive that has been ground down to fit. Do this before installing the engine.

As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.

 

XJ: “Regular” (not Grand) Cherokees ’84-’01
ZJ: Grand Cherokee ’93-’98 (Gen1)
WJ: Grand Cherokee ’99-’04 (Gen2)
YJ: Wrangler ’87-’95 (Gen1)
TJ: Wrangler ’97-’06 (Gen2)

[cruiser54]

And, just so you don't get your hopes up about the "HO" thing.

Ain't worth doing any harness swaps etc. A guy puts an HO in because of availability. Not for the supposed power.

Here's why:

 

HO myth buster

Renix in 90 made 182 HP. HO in 91 made 190 HP. That's 8 HP difference. 

HO only made more HP than Renix at higher RPMs and not a bit more torque. HO had a 58 mm throttle body versus a 52 mm throttle body on a Renix. That’s 20% more air available through the HO throttle body. The HO also had a better design header. See where I'm going with this? 

It’s only a 4% horsepower increase…..

The whole 8HP was not mostly from the head, but from the bigger TB and better exhaust manifold.

Put a 60mm TB from www.strokedjeep.com on your present manifold using the Renix head, eliminate the "crush" in your headpipe with proper re-routing, and go for it. 

HO stands for Highly Overrated.
 

[89 MJ]

13 minutes ago, cruiser54 said:

And, just so you don't get your hopes up about the "HO" thing.

Ain't worth doing any harness swaps etc. A guy puts an HO in because of availability. Not for the supposed power.

Here's why:

 

HO myth buster

Renix in 90 made 182 HP. HO in 91 made 190 HP. That's 8 HP difference. 

HO only made more HP than Renix at higher RPMs and not a bit more torque. HO had a 58 mm throttle body versus a 52 mm throttle body on a Renix. That’s 20% more air available through the HO throttle body. The HO also had a better design header. See where I'm going with this? 

It’s only a 4% horsepower increase…..

The whole 8HP was not mostly from the head, but from the bigger TB and better exhaust manifold.

Put a 60mm TB from www.strokedjeep.com on your present manifold using the Renix head, eliminate the "crush" in your headpipe with proper re-routing, and go for it. 

HO stands for Highly Overrated.
 

This is exactly what I was looking for. Thank you. Your site has already been bookmarked on my phone for a few months. Thanks again. 

[omega_rugal]

you gain 8 hP but lose a lot of low end torque...

 

unless the old renix is toast, fine tune it, follow cruiser´s advice and keep it rolling...

[Minuit]

What people neglect to mention (and where the HO system is a huge upgrade) is everything else where it pertains to having a functional vehicle. No more fusible links. No more 1970s-grade wiring harness jank. A proper engine bay fusebox. Proper grounding out of the box. Much more organized wiring runs. More sealed electrical connectors. Better availability of used parts. No more bouncing speedometer. A cooling system that isn't a pain in the @$$ to work with. Larger A/C compressor. Less 1980s emissions "technology." Less vacuum lines. Much higher "it just @#$%ing works" factor. I don't really care about having 8 more horsepower. I own my trucks to use them, and the HO era makes that easier.

 

The Renix era has some cool stuff about it, and my own Renix truck isn't getting an HO swap. The interiors were a lot more interesting. I like the 1987 grille a lot more than the 1991 grille. The radios are cool. But a 1991 is a better vehicle than a 1990 in practice.

[89 MJ]

3 hours ago, omega_rugal said:

you gain 8 hP but lose a lot of low end torque...

 

unless the old renix is toast, fine tune it, follow cruiser´s advice and keep it rolling...

I did not know there was more low end torque. Thank you. 

[89 MJ]

3 hours ago, Minuit said:

What people neglect to mention (and where the HO system is a huge upgrade) is everything else where it pertains to having a functional vehicle. No more fusible links. No more 1970s-grade wiring harness jank. A proper engine bay fusebox. Proper grounding out of the box. Much more organized wiring runs. More sealed electrical connectors. Better availability of used parts. No more bouncing speedometer. A cooling system that isn't a pain in the @$$ to work with. Larger A/C compressor. Less 1980s emissions "technology." Less vacuum lines. Much higher "it just @#$%ing works" factor. I don't really care about having 8 more horsepower. I own my trucks to use them, and the HO era makes that easier.

 

The Renix era has some cool stuff about it, and my own Renix truck isn't getting an HO swap. The interiors were a lot more interesting. I like the 1987 grille a lot more than the 1991 grille. The radios are cool. But a 1991 is a better vehicle than a 1990 in practice.

Thank you. That is nice info.