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Renix performance?
- Thread starter XJHOX
- Start date
CW
NAXJA Forum User
- Location
- Coeur d'Alene, Idaho
anything that works on an HO engine will work on a RENIX engine exept it will often yield higher gains. swapping on an HO head and manifolds and TB gives a fairly large performance gain. Port the heads and cam it while you are at it and ford injectors along with a bored TB and FIPK would help it perform at its best. Check out Dr. Dino's site.
5-90
NAXJA Forum User
- Location
- Hammerspace
While our colleague CW is correct - the Renix and HO 4.0 are mechanically identical - check your local smog regulations pertaining to engine mods. Many mods which are "type certified" for the 4.0 are NOT certified for the Renix 4.0 - something which those of us unfortunate enough to reside in California find irksome, at the very least.
Apart from that, have fun! Please report on whatever mods you apply and the results you get from so doing, as we are interested...
5-90
Apart from that, have fun! Please report on whatever mods you apply and the results you get from so doing, as we are interested...
5-90
CW
NAXJA Forum User
- Location
- Coeur d'Alene, Idaho
Oh yeah, since I live in Idaho that smog regulation stuff never really crosses my mind. The 4.0 HO's don't have an EGR system so you would run into a problem with that.
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
XJHOX said:
Basically what CW said. Just check your local emission laws before you get too deep into performance mods. As long as they're CARB certified, you're definitely OK.
________________________________________________
Modified 1992 4.0 XJ Laredo UpCountry, 169k miles, AX15, NP231, D35c rear, D30 front
Estimated 240hp@5250rpm/280lbft@3500-4000rpm
1/[email protected], race weight 3490lb
Future mods: 4.6L stroker
Website: Jeep 4.0 performance
Webpages: Electric fan, IAT sensor relocation, Intake manifold heatshield, Oil temp. gauge install, Jeep 4.0 cam specs, Jeep engine dyno graphs, Automotive formulae, CTS resistor trick, MAP adjuster
EndlessMtnFab
NAXJA Forum User
- Location
- Paxtonia, PA
Was just alerted to take a look in 
for a thread ... so here i am. :spin1:
There's plenty you can do to the Renix motor ... even in CA. Just a matter of how much you want to do "on the sly"
I rebuilt my motor and blueprinted as much as I could within my abilities. Attention to tolerances and specs goes a long ways. Good balance job "frees" up wasted HP from harmonics. Keeping ring gap on the tight end of the scale allows the combustion process to do it's job better. Smooth piston tops help a tiny tiny bit. So does decking/surfacing the head and block for straightness. Probably worth .1 point on your compression. There are other little tips and tricks that probably don't do much .. but i did them anyways for reliability.
I had the machinst port the heads very mildly and do some bowl blending and shaping. 3 angle valve job to help the air flow in/out does a lot too. Looking back .. i'm sorry i didn't backcut the exhaust valves. As you'll see below .. the shorter duration cam could probably "exhale" a little better.
On top of that .. i cleaned up the runners in the manifold and made sure they fit the head well (very little was needed, IMO). I aslo installed/adapted an HO throttle body to my Renix manifold. I would suggest for ease of use ... locating the bored out Renix TB. I believe Turbo City offers it. It's bored to 59 mm and is less hassle (and maybe money) than the adapter setup I used. Of course ... you can still install a Renix spacer underneath the TB. If it's the right color, the referee probably won't even notice it.
Then again ... if you put the HO TB on .. you can further bore it out to 62 mm. 6 of one .. half dozen of the other. I doubt you'll gain much more going past 60 mm. The renix head doesn't have as nice of a intake port angle. It's a bit more square .. .which helps the torque. The HO intake port is more angled. More extensive porting will help in this area. Depends what you want your motor to 'feel' like.
An air intake setup can be installed. When it's time for an inspection, simply swap your OE setup back in and play innocent. Most, if not all, ignition upgrades are 50 state legal, so you shouldn't have too many issues with that. I run a ceramic coated Borla (50 state, as you know) to a hi-flow converter (if you're that old ... you can safely change it out .. just have a good reason ready) and a Dynomax catback (50 state again).
As far as the cam goes ... that's the 'grey area' If they don't see it ... was it done? :angel: The cam I chose was one of the Mopar units (worked at a Jeep dealer at the time ... price was great). I have more lift than factory and slightly less duration. End result is a LOT of low end torque and a touch more top end (compared to factory). At the time .. i didn't realize i was only running 75% of my TSP signal. Meaning at WOT ... the TPS was only 75% open. I still have to adjust that (lazy). I suspect it'll pick up even more top end. Degreeing the cam to centerline will ensure it at it's best possible performance as well.
Synthetic oils offer greater protection and are thinner in viscosity. Takes less HP to turn the oil pump. The "frees" up some extra power, IMO.
What's the end result? Well ... for me, best estimates are roughly 215 hp and 300 ft lbs. This going by what the machinist had done/dyno'ed in the past .. and some computer work by Desktop Dyno 2000. For real world results ... i can crack my tires loose in 1st, 2nd, 3rd, and 4th gears. Not spinning them .. but you can def. hear them chirp. I can also .. if i chose... start up in 5th gear and go. That's a manual transmission with 33s and 4.10 gears.
Hope it clears up some confusion what you can/can't do with the Renix motor.
Have fun eating those hondas and toyotas. :laugh2:
Joe
for a thread ... so here i am. :spin1: There's plenty you can do to the Renix motor ... even in CA. Just a matter of how much you want to do "on the sly"
I rebuilt my motor and blueprinted as much as I could within my abilities. Attention to tolerances and specs goes a long ways. Good balance job "frees" up wasted HP from harmonics. Keeping ring gap on the tight end of the scale allows the combustion process to do it's job better. Smooth piston tops help a tiny tiny bit. So does decking/surfacing the head and block for straightness. Probably worth .1 point on your compression. There are other little tips and tricks that probably don't do much .. but i did them anyways for reliability.
I had the machinst port the heads very mildly and do some bowl blending and shaping. 3 angle valve job to help the air flow in/out does a lot too. Looking back .. i'm sorry i didn't backcut the exhaust valves. As you'll see below .. the shorter duration cam could probably "exhale" a little better.
On top of that .. i cleaned up the runners in the manifold and made sure they fit the head well (very little was needed, IMO). I aslo installed/adapted an HO throttle body to my Renix manifold. I would suggest for ease of use ... locating the bored out Renix TB. I believe Turbo City offers it. It's bored to 59 mm and is less hassle (and maybe money) than the adapter setup I used. Of course ... you can still install a Renix spacer underneath the TB. If it's the right color, the referee probably won't even notice it.
Then again ... if you put the HO TB on .. you can further bore it out to 62 mm. 6 of one .. half dozen of the other. I doubt you'll gain much more going past 60 mm. The renix head doesn't have as nice of a intake port angle. It's a bit more square .. .which helps the torque. The HO intake port is more angled. More extensive porting will help in this area. Depends what you want your motor to 'feel' like.An air intake setup can be installed. When it's time for an inspection, simply swap your OE setup back in and play innocent. Most, if not all, ignition upgrades are 50 state legal, so you shouldn't have too many issues with that. I run a ceramic coated Borla (50 state, as you know) to a hi-flow converter (if you're that old ... you can safely change it out .. just have a good reason ready) and a Dynomax catback (50 state again).
As far as the cam goes ... that's the 'grey area' If they don't see it ... was it done? :angel: The cam I chose was one of the Mopar units (worked at a Jeep dealer at the time ... price was great). I have more lift than factory and slightly less duration. End result is a LOT of low end torque and a touch more top end (compared to factory). At the time .. i didn't realize i was only running 75% of my TSP signal. Meaning at WOT ... the TPS was only 75% open. I still have to adjust that (lazy). I suspect it'll pick up even more top end. Degreeing the cam to centerline will ensure it at it's best possible performance as well.
Synthetic oils offer greater protection and are thinner in viscosity. Takes less HP to turn the oil pump. The "frees" up some extra power, IMO.
What's the end result? Well ... for me, best estimates are roughly 215 hp and 300 ft lbs. This going by what the machinist had done/dyno'ed in the past .. and some computer work by Desktop Dyno 2000. For real world results ... i can crack my tires loose in 1st, 2nd, 3rd, and 4th gears. Not spinning them .. but you can def. hear them chirp. I can also .. if i chose... start up in 5th gear and go. That's a manual transmission with 33s and 4.10 gears.
Hope it clears up some confusion what you can/can't do with the Renix motor.
Have fun eating those hondas and toyotas. :laugh2:
Joe
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