90 Renix ~ Need more power, whats avail.

[RWKHausSupply]

Long story short. Got a New remanufactured engine in a 90 with Every (yes every) sensor new, as well as new stock injectors, new alt, PS pump, fan clutch, and a pacesetter header.

I added a cage and other stuff, and now with the 4:88's on 35's I find that up hill is a bit more work that I think it likes.

What can I do to a Renix beside the exhaust (I also have a custom short full exh system), to help make power? I just looked and found alot on the newer stuff, but not much on the renix model. I dont really want to do a motor swap, but may need to if I cant get a reliabe, true say 30 HP from this with out doing a super charger/turbo or nitrous.

Help with advise would be great...

Thanks

 

[Slo-Sho]

1st off...Let me ask you this, How much are you willing to spend?

 

[RWKHausSupply]

not looking to spend more then a SBC conversion or tubro set up.. so like 400-600$. I figure I can fab pretty much everything for a turbo setup minus the unit, for less then 300$ with the BOV, and WG. then just get a used stock unit from like a SRT for close to free (lots of friends in that area), and a greddy E-01 / emanage unit, and injectors. so total around 900-1000$ I would think.

 

[CW]

A cam swap and a either an HO head conversion or a port and polish on the renix head will get you there. An HO tb and a fipk will help too.

 

[RWKHausSupply]

A cam swap and a either an HO head conversion or a port and polish on the renix head will get you there. An HO tb and a fipk will help too.

Ok so who or what cam to get? Is there a over the shelf product or do I have to have a custom grind done for the 4.0?

Also head work? Is it a simple port matching, and polish the exhaust and blend the combustion chamber (bowl)? or is there more needed for the renix head? The motor has maybe 2000 miles on it. So I would just work with what I have now, not to mention the need to calif. smog it next yr.

I do have the crusty's tube on it but would consider a TB IF it really was worth the high $?

And is it poss to convert the older renix to a newer TB? If so I will search for info.

Thanks

Oh and you honestly think on the renix that would yield me say 40HP? I can do most all that work so thats what about a 500$ (with TB) total investment..

 

[XJoshua]

2000 XJ 4.0L Intake Manifold
Mustang Throttle Body
Port and Polish of the Renix Head
Stronger Valve Springs

Should make about 20-25HP

 

[RWKHausSupply]

2000 XJ 4.0L Intake Manifold
Mustang Throttle Body
Port and Polish of the Renix Head
Stronger Valve Springs

Should make about 20-25HP

no cam needed? Just stocker?

 

[XJoshua]

You can cam, if you do that, make sure they are offset not 270/270 but just a random number 260/280 someone will go in more detail about this, im just starting to understand cams and some calculations for using them.

I plan on doing all of the above in my previous post on my stroker with a larger cam, and other stuff.

 

[CW]

A cam is by far the biggest bang for your buck. Before you chose a cam you need to consider what you will be doing with your jeep. If it's an offroader/dd and being able to keep pace up hills is your real concern then you want a cam that delivers torque over hp. I run the comp 250h in my stroker and it makes great low end power. Search around this forum and you will find all the answers you need. Check out dino's page too.

 

[XJING]

2000 XJ 4.0L Intake Manifold
Mustang Throttle Body
Port and Polish of the Renix Head
Stronger Valve Springs

Should make about 20-25HP

Should be a headache and not produce much else

Because the Renix intake and exhaust openings are not the same as "newer castings" I dont think you are going to be able to port match the 2000 intake to the renix head.
Secondly, you dont have enough motor stock, Or with a cam to pull a bigger TB like the mustang has. Artsound on Ebay sells bored Renix TB's (good mod)
Porting and polishing the renix head works great, I have done it, If I was gonna do it again, I would just go with a "91-95 HO Head" (Which you then can do the newer Intake manifold, some people think the jury is still out on the actual power the newer manifolds create.)
Lastly, Stronger valve springs, are not nessasaraly needed, depends on the grind of your cam. ( a decent rv cam that gives you even more low end torque is what you want in a 4.0)
Good Luck

 

[N20Jeep]

SPRAY THE F'N PISS OUT OF IT....

 

[Hellbent]

i have one of artsound's bored tb's. i put it on at the same time i put in the 5.0 injectors, rusty's tb spacer, and k&n filter(which gets replaced with paper for desert trips). all these things combined made one heck of a difference in throttle response and top-end pull. i am very happy with the performance now(i'm not running 35's but...), and would definitely recommend those mods to any renix-rig owners.

 

[Dr. Dyno]

What can I do to a Renix beside the exhaust (I also have a custom short full exh system), to help make power? I just looked and found alot on the newer stuff, but not much on the renix model. I dont really want to do a motor swap, but may need to if I cant get a reliable, true say 30 HP from this with out doing a super charger/turbo or nitrous.

Help with advise would be great...

Thanks

Rusty's intake with home fabbed heatshield
Bored Renix TB from ebay
Header
Carsound 2.5" high-flow cat
2.5" catback exhaust
Replace clutch fan with electric unit
Magnecor plug wires
Relocate IAT sensor to intake

Swapping in a cam is a PITA and not a good bang per buck mod on its own. Better to combine it with a ported HO head, '99+ HO intake manifold, and '91-'95 bored 62mm TB with Renix TPS adapted to it.

 

[RWKHausSupply]

Rusty's intake with home fabbed heatshield - PRETTY MUCH GOT THIS
Bored Renix TB from ebay - THINKING THIS IS NEXT
Header - GOT THIS
Carsound 2.5" high-flow cat - GOT THIS
2.5" catback exhaust - GOT THIS
Replace clutch fan with electric unit - HEARD THIS WAS NOT GOOD?
Magnecor plug wires - GOT THIS
Relocate IAT sensor to intake - THATS HOW A RENIX IS NOW?

Swapping in a cam is a PITA and not a good bang per buck mod on its own. Better to combine it with a ported HO head, '99+ HO intake manifold, and '91-'95 bored 62mm TB with Renix TPS adapted to it.

So what am I going to have to relocate to do a HO head and manifold? I know I loose the EGR to that will screw me for smog for ever though.

So porting a Renix head (150$) and port matching the renix manifold and header to the head with a Cam (180$) and a larger TB (175$) would not be a worthy investment for the $? What if I did the above but no cam? Would it really help that much?

Thanks

 

[XJING]

I ported my renix head and did the bore of my TB at the same time, already had the better air intake and header as you do. Its worth some power, I did the cam shortly after and every little bit helps, but I think lookin back the most gains are made my making it breathe easier and exhaust quicker, So in my opinion do the bored TB and enjoy the bit you get from it, The 4.0 is a torquey motor, not much of a hot rod. So dont look to get a whole lot more unless you are gonna stroke it.
Good Luck

 

[Slo-Sho]

Sounds like you have the mechanical aptitude so if you can deal with the down time of pulling the head and gasket matching it you'd be surprised at the amount of metal you can remove. The bowl area behind the valves as well as the valve shrouding is horrible. Needless to say there is much room for improvement. If you don't want to cam it right now, you can always modify the head to accept 1.7 ratio rockers while it is off. A high altitude CPS as well as a MAP adjuster will also help the timing and fuel delivery.


You say the motor has 2k on it? I'd let it break in some more before hammering on it. I can imagine the piston rings aren't even seated yet so there is more power on the way as the miles go by.

Oh, one more thing...was this motor NOS (New Old Stock) or a reman? Man, I wish I had a new Renix. It is rumored the old school Renix block quality is also better than later years.

 

[RWKHausSupply]

Sounds like you have the mechanical aptitude so if you can deal with the down time of pulling the head and gasket matching it you'd be surprised at the amount of metal you can remove. The bowl area behind the valves as well as the valve shrouding is horrible. Needless to say there is much room for improvement. If you don't want to cam it right now, you can always modify the head to accept 1.7 ratio rockers while it is off. A high altitude CPS as well as a MAP adjuster will also help the timing and fuel delivery.


You say the motor has 2k on it? I'd let it break in some more before hammering on it. I can imagine the piston rings aren't even seated yet so there is more power on the way as the miles go by.

Oh, one more thing...was this motor NOS (New Old Stock) or a reman? Man, I wish I had a new Renix. It is rumored the old school Renix block quality is also better than later years.

The motor was a titan remanufacture. It was fully tested with a "birth certificate", giving the oil pressure, estimated tq and hp, and comp.

well I figured that a quality time consuming porting and polishing job, along with a header and TB along with a cam, has got to help....

Bigger cam mixed with a milled head and thinner head gasket (high comp), with the needed larger TB and free'er flowing air filter setup, and then the header to evacuate it faster, all together should be a good 30-40 more hp?

I am not worried at all about torque, that is fine... But freeway hills are not very good at all..

 

[Dr. Dyno]

So what am I going to have to relocate to do a HO head and manifold? I know I loose the EGR to that will screw me for smog for ever though.

So porting a Renix head (150$) and port matching the renix manifold and header to the head with a Cam (180$) and a larger TB (175$) would not be a worthy investment for the $? What if I did the above but no cam? Would it really help that much?

Thanks

To keep things simple and keep the costs down just port your existing Renix head, shave 0.010" from the head surface and use the Mopar/Victor head gasket to raise the compression ratio to 9.1:1, and use a 59mm bored Renix TB. That way you don't have to worry about matching the intake manifold to the head, and the Tb to the intake manifold. You also retain the EGR system so you'll pass the visual inspection by the smog cops.
As for the cam, the Crower 44243 should match your engine very well and the valve lift is modest enough for you to retain the stock valve springs, so that'll be another cost saving.