MoeBoy Posted December 4, 2013 Share Posted December 4, 2013 Hey all, As the title says i'm new to the Renix and I have some questions before i start driving this thing. It's a 1990 model with an ax15 (i believe). As of now, i've only revved the engine to about 3k RPM and I'd like to go to 5k but i don't feel comfortable with it. With around 150k on the engine, what should i be doing maintenance wise before really stressing this thing. I don't want to blow it up! Thanks in advance Josh Link to comment Share on other sites More sharing options...
relyt120 Posted December 4, 2013 Share Posted December 4, 2013 You shouldn't need to get it to 5k rpm, I've never purposefully gotten my renix 4.0 to 5k rpm during normal operating, even on the highway. Always a good place to start:http://comancheclub....ers-renix-tips/ Link to comment Share on other sites More sharing options...
gogmorgo Posted December 4, 2013 Share Posted December 4, 2013 The question I'm asking myself is why you need to rev that high... apart from driving like I do... a bit of a hoon... And my MPG reflects my driving habits. Peak torque is around 2200 rpm, and I can accelerate to highway speeds without breaking 2000. It just takes a bit longer. But I'd just do standard stuff for buying a new vehicle, plugs, wires, cap & rotor, change fluids, check all lights are working, and not worry about the engine unless there's cause to worry. 150,000 miles really isn't all that much for a 4.0. There are some on here with twice that. Link to comment Share on other sites More sharing options...
MoeBoy Posted December 4, 2013 Author Share Posted December 4, 2013 It's not so much that I NEED to rev that high, but i'd like to know the engine could do it if necessary. I have the notion to turn this truck into somewhat of a drift-o-manche and i'd like it to not grenade. I read on another post that max HP is made right before 5k rpms. Josh Link to comment Share on other sites More sharing options...
cruiser54 Posted December 4, 2013 Share Posted December 4, 2013 It's not so much that I NEED to rev that high, but i'd like to know the engine could do it if necessary. I have the notion to turn this truck into somewhat of a drift-o-manche and i'd like it to not grenade. I read on another post that max HP is made right before 5k rpms. Josh Yes, it will and will be fine. Run a quality oil filte rlike Wix or Napa gold and some good oil. Link to comment Share on other sites More sharing options...
DangerWillRbnsn Posted December 8, 2013 Share Posted December 8, 2013 I just picked mine up with 250k on it. I resealed it, top to bottom, New plugs, wires, cap/rotor, fuel filter, and measured all the sensors to ensure proper operation (resistance values, ohms values, etc) then compression tested it. Once I was happy it was indecent shape, I have her a good pull to red-line. Nothing came apart, no knock, and she pulled strong. While 5k isn't necessary it was nice to know I can rev it if I had to. Link to comment Share on other sites More sharing options...
Eagle Posted December 8, 2013 Share Posted December 8, 2013 Hey all, As the title says i'm new to the Renix and I have some questions before i start driving this thing. It's a 1990 model with an ax15 (i believe). As of now, i've only revved the engine to about 3k RPM and I'd like to go to 5k but i don't feel comfortable with it. With around 150k on the engine, what should i be doing maintenance wise before really stressing this thing. I don't want to blow it up! Thanks in advance Josh 5,000 is the redline, and if you try to go beyond that the hydraulic lifters will limit you due to valve float. That said, the torque peak is at 2400 RPM and the horsepower peak is at (IIRC) 4700 RPM, so trying to hit or exceed redline is not just wasteful, it's counterproductive. I have logged easily over a million miles behind the 4.0L engine in various XJs and MJ, and I don't think I've ever gone higher than 3,500 RPM. There's just no reason do do so. Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 8, 2013 Share Posted December 8, 2013 Nobody picked up that a 1990 is not Renix? Link to comment Share on other sites More sharing options...
jimoshel Posted December 8, 2013 Share Posted December 8, 2013 Apparently you were the first. Link to comment Share on other sites More sharing options...
gogmorgo Posted December 8, 2013 Share Posted December 8, 2013 Then what was it if it wasn't Renix? First year of the HO was '91. Link to comment Share on other sites More sharing options...
ParadiseMJ Posted December 8, 2013 Share Posted December 8, 2013 90 = Renix (I've had 2 of them) 91 = HO HO HO HO Link to comment Share on other sites More sharing options...
Eagle Posted December 9, 2013 Share Posted December 9, 2013 Nobody picked up that a 1990 is not Renix? 1990 was the last year for Renix. 1991 was the first year for the HO. Link to comment Share on other sites More sharing options...
relyt120 Posted December 9, 2013 Share Posted December 9, 2013 Apparently you were the first. :rotf: jim is such a smart alec Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 9, 2013 Share Posted December 9, 2013 Nobody picked up that a 1990 is not Renix? 1990 was the last year for Renix. 1991 was the first year for the HO. So Chrysler continued for two years........Sorry, my mistake. Link to comment Share on other sites More sharing options...
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