Need help, found stroked 4.5L cherokee, but 93 oct only?

[slick]

I just sold my built 06 cummins and am on the search for a cherokee when I stumbled upon a 2000 with 4.5l stroker kit/lift etc. When I called the owner who is a (insert a bunch of letters for being a certified mechanic) mechanic, it turns out he didnt order a kit or anything like that, but here are the specs of the build, which he tells me REQUIRES 93 octane, anything less and it pings/etc. (I was interested until he told me this). So upon further research, im trying to figure out after reading a ton of threads on here why his jeep is requiring 93 octane, and if there is anything that can be done to make that not be required basically.


It still has the stock throttle body, he installed crank and rods from 4.2L, comp cam part no. 682314, timing chain set, and ford motorsport injectors. He stated that he probably went a little overboard with the cam selection and that it is one step larger then what he should of put in.


Being a total noob to all this stroker stuff, I come to you guys to ask basically why this build requires 93 oct and what I should do or what options I have. I want to buy the jeep,but i dont want to pay 4.30 a gallon or 30 cents more a gallon for fuel

[shawnxj]

that's only 6 bucks more a tank for a 20 gallon tank. personally neither of my vehicles require 93 octane but that's all they ever see and i get a little better mileage out of them and more power in the process

[SilverXJ]

My current stroker requires at least mid grade. I haven't able to play with the AFR that much but I might be able to run 89 if I run it very rich. That uses KB 944 pistons. The previous one that used standard non-dished 4.0L pistons and 4.2L rods with a ridiculous quench also required premium and it had the 68-231-4 cam. There is actually nothing wrong with his cam selection.

[slick]

ok, thanks for clarifying all of that.

jeep has 166k miles on body, 2k on stroker kit. 3.5" on 31's, looks really clean, small dent on rear hatch. asking 5500 obo.


would you go for it?

I am also looking at a 01' limited, 120k miles, pretty clean as well, brand new top end from the overheating issue (blew headgasket) 4500$.

[Cheromaniac]

ok, thanks for clarifying all of that.

jeep has 166k miles on body, 2k on stroker kit. 3.5" on 31's, looks really clean, small dent on rear hatch. asking 5500 obo.

would you go for it?

Yeah why not? If it's indeed a 4.5L stroker, the owner probably reused the stock pistons so the SCR will be ~9.7:1 and that's the likely reason why the engine needs 93 octane gas. I wouldn't even worry about that. My main concern would be the 0331 head if he reused it 'cause those heads are crack-prone. It's probably OK at the moment but something to watch out for. The same concern would apply to any '00-'01 4.0 XJ.

[92tank]

i was running reg (87 oct) in my stroker for a little bit but know that im runnung prem (92 oct) it likes it alot better. with the reg i was getting about 14-15 mpg and with the prem it gets about 17-18 mpgs.