comancheboy Posted November 4, 2009 Share Posted November 4, 2009 Thinking about building a stroker motor out of my 1988 non high output motor. Ben hunting around on the internet trying to find a set up useing the non H.O motor but can't find one. I'm thinking maybe converting the non H.O motor to the high output head etc. to make it easyer for the stroker kit but i can't deside what to do SO WHAT DO YOU THINK????? Link to comment Share on other sites More sharing options...
Geonovast Posted November 4, 2009 Share Posted November 4, 2009 viewtopic.php?f=2&t=19299 Link to comment Share on other sites More sharing options...
comancheboy Posted November 4, 2009 Author Share Posted November 4, 2009 Thanks for the link. Sounds like i mite have to step it up and put a H.O in it looks like you get the best power out of the H.O motor. Is there any links that break down the swap to high ouput .Like what you need besides motor ecu and some rewiring some things in the engine bay and maybe under dash?? Link to comment Share on other sites More sharing options...
Pete M Posted November 4, 2009 Share Posted November 4, 2009 To do the whole HO swap, you need to swap the entire wire harness out of the donor XJ, dash and all. what size tires do you have? What gears? Link to comment Share on other sites More sharing options...
comancheboy Posted November 4, 2009 Author Share Posted November 4, 2009 Dam sounds like alot of work for some extra power. Well better build this stroker good to make it worth my time. Is there a painless wireing kit or another company that mite sell a kit so you don't have to use all the ripped out old wire out of the donor jeep. Link to comment Share on other sites More sharing options...
Pete M Posted November 4, 2009 Share Posted November 4, 2009 nope. Go buy a complete donor XJ (that's in the best running shape you can afford). Gears are a better solution to power problems. Link to comment Share on other sites More sharing options...
Eagle Posted November 4, 2009 Share Posted November 4, 2009 Ya know ... Just thinkin' out loud here. I have NOT done this, but with 287,000 miles on the '88 XJ I'm ... exploring options. Jeep sells (or used to sell) an MPFI conversion kit for the old, carbureted 4.2L engine in the early YJ Wranglers. Essentially, the conversion was the intake manifold, throttle body, injection, and engine room wiring harness from a 1994 Wrangler 4.0L with the HO MPFI system. It was NOT necessary to rewire the entire vehicle to install this kit. If you can convert a carbureted Wrangler to the HO MPFI without rewiring the entire vehicle, I have trouble understanding why there is any need to rewire the entire chassis when the engine harness appears to be functional as a stand-alone conversion. Link to comment Share on other sites More sharing options...
glundblad Posted November 4, 2009 Share Posted November 4, 2009 nope. Go buy a complete donor XJ (that's in the best running shape you can afford). Gears are a better solution to power problems. I don't mean to hijack this thread but Pete's comment above brought up a question I pondered awhile back. It contradicts my conclusion. Gearing doesnt increase power (unless you stay in first gear). Specifically, see Eagle's comments in my thread below. My conclusion was the drivetrain would generate the same torque if I wound the engine a little higher. I am running 3:07 and was considering switching to 3:73 but I concluded I would have the same result (or close depending on speed of course) if I kept it in 4th gear rather than 5th. viewtopic.php?f=2&t=18501&hilit=gearing Anyone agree or disagree? Link to comment Share on other sites More sharing options...
Pete M Posted November 4, 2009 Share Posted November 4, 2009 your drivetrain needs the extra leverage on those bigger tires. It's like having a too-short handle on your ratchet. It's harder to turn that socket. Whip out the breaker bar with the pipe extension and it's much easier to turn. Having gears not matched to your bigger tires is actually harder on your drivetrain (especially with regard to auto transmission fluid temps and manual trans clutches) Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 4, 2009 Share Posted November 4, 2009 Jeep sells (or used to sell) an MPFI conversion kit for the old, carbureted 4.2L engine in the early YJ Wranglers. Essentially, the conversion was the intake manifold, throttle body, injection, and engine room wiring harness from a 1994 Wrangler 4.0L with the HO MPFI system. It was NOT necessary to rewire the entire vehicle to install this kit. If you can convert a carbureted Wrangler to the HO MPFI without rewiring the entire vehicle, I have trouble understanding why there is any need to rewire the entire chassis when the engine harness appears to be functional as a stand-alone conversion. Hesco developed these kits for Mopar and still sell them (one for auto tranny; one for standard). Not cheap though.......... http://www.hesco.us/shop.asp?action=details&inventoryID=43025&catId=7577 Link to comment Share on other sites More sharing options...
sinkrun Posted November 5, 2009 Share Posted November 5, 2009 :eek: Link to comment Share on other sites More sharing options...
Eagle Posted November 5, 2009 Share Posted November 5, 2009 nope. Go buy a complete donor XJ (that's in the best running shape you can afford). Gears are a better solution to power problems. I don't mean to hijack this thread but Pete's comment above brought up a question I pondered awhile back. It contradicts my conclusion. Gearing doesnt increase power (unless you stay in first gear). Specifically, see Eagle's comments in my thread below. My conclusion was the drivetrain would generate the same torque if I wound the engine a little higher. I am running 3:07 and was considering switching to 3:73 but I concluded I would have the same result (or close depending on speed of course) if I kept it in 4th gear rather than 5th. viewtopic.php?f=2&t=18501&hilit=gearing Anyone agree or disagree? More gear at the axle can't increase the amount of torque or horsepower produced by the engine at any particular RPM, but the torque and horsepower at the rear wheels are a product of the engine power multiplied by the total final drive ratio. This does not contradict the conclusions from your other thread. More gear allows whatever power/torque the engine is producing to apply more leverage to the rear wheels. Conversely, because of the increased rolling radius, larger tires work the opposite. 31x10.50-15s, as an example, run just about 10 percent fewer revolutions-per-mile than stock 225/75-15s. That's the equivalent of putting in 10 percent LESS gear. In other words, if you have a 5-speed with 3.08 gears, on 31s you have the equivalent of 2.77 gears. Worse, the bigger tires are heavier, so you have less gear trying to overcome MORE inertia. Yes, you might have the same result leaving it in fourth gear ... if you only drive in fourth gear. But you would not see any improvement in 1st, 2nd, or 3rd. Regearing the axle gives you more power multiplication in ALL gears. Link to comment Share on other sites More sharing options...
87Warrior Posted November 5, 2009 Share Posted November 5, 2009 Wow, they tacked on an extra $1,000 since I last looked at that kit for a YJ. I also recall several 4.2 guys splicing the XJ wiring harness into their existing set up to get the fuel injection. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 5, 2009 Share Posted November 5, 2009 Wow, they tacked on an extra $1,000 since I last looked at that kit for a YJ. I also recall several 4.2 guys splicing an XJ the wiring harness into their existing set up to get the fuel injection. Yeah, that's true. You'd think the price would go down, since this kit is offered by several other vendors and they appear to be readibly available. Also the demand has got to be decreasing since a lot of carbed 4.2's are history now, unless the individual kit parts are made of unobtainium. I'll never understand economics and how supply and demand works. :nuts: Link to comment Share on other sites More sharing options...
Eagle Posted November 5, 2009 Share Posted November 5, 2009 Back when the kit came out, it was widely understood (which is why I wrote) that it WAS the engine room harness and parts from a 1994 YJ. As long as Jeep was building a version of the HO motor and puting it in something like a Wrangler, the parts would have kept rolling off the assembly line (or rolling in the door from subcontractors, more likely). Now that Jeep has retired the 4.0L engine, there's no flow of the parts, so they must have to be specially made up in smaller quantities. Link to comment Share on other sites More sharing options...
Gjeep Posted November 5, 2009 Share Posted November 5, 2009 I too have stroker plans in the future...so I've been looking into how to 'MPI' my Renix. Hesco sells the MPI wiring harness alone for ~$500. I plan on patching together a HO using this, the later 4.0L intake manifold, etc. You may want to take a peek at their website. Link to comment Share on other sites More sharing options...
Pete M Posted November 5, 2009 Share Posted November 5, 2009 I've been looking into how to 'MPI' my Renix. I'm confused. :hmm: all 4.0Ls are MPI. Link to comment Share on other sites More sharing options...
Eagle Posted November 5, 2009 Share Posted November 5, 2009 I too have stroker plans in the future...so I've been looking into how to 'MPI' my Renix. See, now you've even got Pete confused. Me, too, but I think what we have here is a misappropriation of terminology. "MPI" (or "MPFI") is the acronym for Multi-Port Injection (or Multi-Port Fuel Injection). As Pete noted, ALL the 4.0L engines are multi-port injected. The other option is TBI (Throttle Body Injection), which is what was used on the '86 through '90 4-cylinder engines. I think what you mean is that you want to upgrade from the Renix MPFI system to the newer Mopar MPFI system. Link to comment Share on other sites More sharing options...
Blue XJ Posted November 6, 2009 Share Posted November 6, 2009 Maybe I am not understanding properly, but to run a HO head/engine in your Renix jeep, you just need to make an adapter for your TPS. Everything else swaps right over, at least it did on mine. Link to comment Share on other sites More sharing options...
Eagle Posted November 6, 2009 Share Posted November 6, 2009 Maybe I am not understanding properly, but to run a HO head/engine in your Renix jeep, you just need to make an adapter for your TPS. Everything else swaps right over, at least it did on mine. It appears the question is about updating a Renix to the newer Mopar system. Link to comment Share on other sites More sharing options...
Blue XJ Posted November 8, 2009 Share Posted November 8, 2009 I was thinking it was just swapping the motor over, not all the wiring. Oops, its been a long week, :doh: Link to comment Share on other sites More sharing options...
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