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Unread 07-18-2010, 09:15 AM   #1
VinceAustria
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Difference between an HO 4.0L and non HO?

hello, whats the difference between a HO and a non ho-engine? i read that the non-ho offers a little bit more torque at lower rpm....is that true?

would you recommend a non-ho?

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Unread 07-18-2010, 09:19 AM   #2
ChEaPsK87
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the HO puts out more HP and TQ. HO = High Output

over 1/2 the people in here probably are running the regular ol' 4.0 so i would have to say there is nothing wrong with it
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Unread 07-18-2010, 09:23 AM   #3
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I've owned both and not much difference at all in my opinion.
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Unread 07-18-2010, 09:26 AM   #4
tjjeepwrench978
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Welll the HO has a little different head design, although the head and block castings in the HO's are not as strong as the NVH motors, nvh block 96-99 I have a 98 nvh 4.0 with a flokooler water pump, stage 3 clutch, poly motor mounts, royal purple oil alum radiator, and i cant killl it , My 94 HO dropped a valve Use a,,, 96-99 motor and when you swap in use the intake and sensors from your motor they willl alll swap over, brackets sensor everything swaps, distributor tooo, dont forget to do full gaskets when you get a motor including the rear main seal,,


Small changes were made to the cylinder head for the 1995 model year. In 1996, the engine block was redesigned, and a new strengthened unit was then used. The new block made use of more webbing cast into the block, and a stud girdle for added rigidity of the crankshaft main bearings. The cylinder head was again changed around 1998 to a lower flowing, more emissions-friendly design. Engines installed in 1999 Grand Cherokees carried the PowerTech name, which had been used intermittently in prior years and on other Chrysler truck and SUV engines. The name was subsequently passed on to 4.0s in the other Jeep models which used the engine, the Cherokee and Wrangler.

pre 96 190 hp 225 ftlbs, 96 up 190 hp 235ftlbs


so technically the 96 motors have 10 more ftlbs of torque

oh yeah the stud gurdle tooo
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Unread 07-18-2010, 01:14 PM   #5
oderalxjlaredo
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Just to add to what 978 said, I think the non-ho (i.e, Renix) 4.0L engines only made about 177 hp. They were used in XJs from 87-90 or 91.
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Unread 07-18-2010, 01:26 PM   #6
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Quote:
Originally Posted by oderalxjlaredo View Post
Just to add to what 978 said, I think the non-ho (i.e, Renix) 4.0L engines only made about 177 hp. They were used in XJs from 87-90 or 91.
only made about!?! my wife's 96 camaro z28 is only rated at 265 HP. i mean 100 HP is not that much compared to the 1.7 liters size difference. even a 1976 corvette only made 265 HP. so i would say 177 HP is not too bad really
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Unread 07-18-2010, 02:33 PM   #7
tjjeepwrench978
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no on wikipedia it had the breakdown look under AMC 6 ru talking wheel or bhp, cuz the jeep 4.0 on a dyno only throws like 70hp wheel on Trucks tv they ran the dyno numbers, and stock is sometthing like 78 whp
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Unread 07-18-2010, 03:08 PM   #8
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That was on a tired 4.0 that had been sitting for a while. A 4.0 in good working condition should produce around 120 to 130 rwhp.
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Unread 07-18-2010, 04:09 PM   #9
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well add into the account 35 mud terrains, and I believe they had in on a 4 wheel dyno,,,,,Factory ratings are the NVH #motors are 10 more ftlbs of torque thats it, i woouldnt think that those specs are off at all. I would choose the NVH just because of strength issues, Girdle,


From what i read rwhp in 2 wheel is around 122 rwhp, in 4 wheel I guess you would what at least halve that

well apparently RIPP mods Dyno shows a turbo wrangler making 140 rwhp

http://www.youtube.com/watch?v=xmCU_BL-la0
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Unread 07-18-2010, 05:27 PM   #10
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Quote:
Originally Posted by tjjeepwrench978 View Post
no on wikipedia it had the breakdown look under AMC 6 ru talking wheel or bhp, cuz the jeep 4.0 on a dyno only throws like 70hp wheel on Trucks tv they ran the dyno numbers, and stock is sometthing like 78 whp
If you read the Wiki article you cited, you would see that there is a specific mention of the Renix-controlled AMC 242 engines.

Quote:
The 1987 RENIX 4.0 made 173 hp (129 kW) and 220 lbft (300 Nm) of torque. In 1988, the 4.0 received higher flowing fuel injectors, raising output to 177 hp (132 kW) and 224 lbft (304 Nm).
The Renix 4.0 was used in Cherokees/Commanches only.

In 1991, Chrysler was able to pull more power out of the engine with an improved head design and new computer control system, at which time they added the "High Output" moniker. Power remained at the 190 hp level through several later head designs ('96, '98) that improved NVH (noise, vibration and harshness) and emissions.
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Unread 07-18-2010, 05:29 PM   #11
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Originally Posted by ChEaPsK87 View Post
only made about!?! my wife's 96 camaro z28 is only rated at 265 HP. i mean 100 HP is not that much compared to the 1.7 liters size difference. even a 1976 corvette only made 265 HP. so i would say 177 HP is not too bad really
I was comparing to later incarnations of the 4.0 only. I agree, it was a remarkable engine for its time with good power, good torque, and legendary reliability.
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Unread 07-18-2010, 06:25 PM   #12
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Quote:
Originally Posted by oderalxjlaredo View Post
If you read the Wiki article you cited, you would see that there is a specific mention of the Renix-controlled AMC 242 engines.



The Renix 4.0 was used in Cherokees/Commanches only.

In 1991, Chrysler was able to pull more power out of the engine with an improved head design and new computer control system, at which time they added the "High Output" moniker. Power remained at the 190 hp level through several later head designs ('96, '98) that improved NVH (noise, vibration and harshness) and emissions.
so 170 ish HP to 190ish HP and around the same torque gains. i will go for oldschool less computer controlled and cheaper parts. and i can gain that much HP with a few mods that probably cost cheaper than the increased price that came with the HO.
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Unread 07-18-2010, 08:11 PM   #13
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Well, I think it's equally computer controlled whether it's a Chrysler computer or a Renault/Bendix (Renix) computer. I had an 89 XJ (another Renix year) until a few weeks ago, and while I loved the thing to death, it was a pain to get sensors and related parts for it, and also fairly difficult to diagnose problems with. I agree about the power, though: I really don't think 13 horsepower is really significant on scale of 170-190 hp. Also, I think the guys that build the 4.6 strokers tend to prefer the early engines because those computer controls are easier to hack to work with the larger displacement. If your Renix treats you right, there's definitely no reason to dump it.
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Unread 07-18-2010, 09:51 PM   #14
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No Hack on the storker motors, just larger injectors.

Most of the HO name is due to the head flowing better. The block was modified as previously mentioned for NVH. Also in 1999 the intake was modified to flow better.
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Unread 07-19-2010, 06:14 AM   #15
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Quote:
Originally Posted by Diamond-x View Post
No Hack on the storker motors, just larger injectors.

Most of the HO name is due to the head flowing better. The block was modified as previously mentioned for NVH. Also in 1999 the intake was modified to flow better.
I disagree on the head being the largest contributor to the HP increase. While it is of better design, and surely flows better on the top end, there are a few other contributing factors to consider when analyzing the HP increase.

First of all, a more sophisticated fuel injection system was used. Secondly, a much improved exhaust manifold was used. Thirdly, the throttle body size was increase from 52mm to 58mm. Fourthly, EGR was eliminated with the introduction of the HO.
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