Upgraded gearing KZJ78

[BurnsTACP]

Hey guys I have a 93 KZJ78 with a 1KZTE I threw some 33s on and it’s sluggish as all hell. I want to upgrade the gearing, and I’m new the the whole 4x4 thing. I’m taking it to a shop (West Texas Off-road) to have the work done. They haven’t ever worked on a prado so I’m trying to get as much info before we tear stuff apart and begin ordering parts. What axles are in the truck stock? What recommendations do you guys have regarding this undertaking?

 

[GTSSportCoupe]

Hey guys I have a 93 KZJ78 with a 1KZTE I threw some 33s on and it’s sluggish as all hell. I want to upgrade the gearing, and I’m new the the whole 4x4 thing. I’m taking it to a shop (West Texas Off-road) to have the work done. They haven’t ever worked on a prado so I’m trying to get as much info before we tear stuff apart and begin ordering parts. What axles are in the truck stock? What recommendations do you guys have regarding this undertaking?

33s aren't really big tires. Why not intercool and tune your motor? 1KZTE can make a ton of power with not much effort. That thing should rip up hills no problem.

If you're really into re-gearing, you could try to get ahold of some LJ78 4.88 diffs. Should be a bolt in affair AFAIK. But you probably won't like the high rpms on the highway.

 

[BurnsTACP]

I do plan to tune the motor some. I haven’t gotten around to it yet though. I don’t have a boost gauge installed, but plan to install an EGT and boost gauge/controller when we do the gears. It’s already got a 3” turboback exhaust. The thing is sooooo slow it’s unbearable, so it makes me think the boost must be way down on this thing.

 

[GTSSportCoupe]

I do plan to tune the motor some. I haven’t gotten around to it yet though. I don’t have a boost gauge installed, but plan to install an EGT and boost gauge/controller when we do the gears. It’s already got a 3” turboback exhaust. The thing is sooooo slow it’s unbearable, so it makes me think the boost must be way down on this thing.

Get your gauges installed and take it from there. I think if you sort out your power issues your desire/need for different gears will dissappear. I think the KZJ78 came with 4.3 gears? That is a pretty nice ratio for 33" tires. If you were running 35" or larger, then the 4.88 gears would be nice.

 

[BurnsTACP]

I plan to pick up a trans cooler. And if there were some sort of FMIC kit around I’d snatch it up in a heartbeat. Is there anything I should be looking at picking up to keep from dealing with boost or fuel cut? Again I apologize if these are basic questions. Not only am I new to this type of vehicle I’m new to diesels. My other three cars are a GTR, Supra, and an Evo, so I’m not new to cars or turbos, but starting to venture into new territory.

 

[Waikato Willy]

check out my posts, these things crank along really good, not super fast by any means but not gutless , can usually overtake people on the open road up hills at 100km/hr, I doubt 33" tyres will be causing problems

 

[BurnsTACP]

Yeah we definitely don’t have that kind of power at all. I have to carry speed into a hill or I’ll end up dragging ass about 60mph up hill just trying to crest it.

 

[Indestructible 47]

Imho, leave the gears as you will want the taller ratio if and when you upgrade the motor, otherwise it will rev way to high. I had a friend that used to say, build the truck and once it's built do the gears.

Yeah we definitely don’t have that kind of power at all. I have to carry speed into a hill or I’ll end up dragging ass about 60mph up hill just trying to crest it.

That sounds normal enough, i doubt boost is lower than stock, these things are no speed machines but can go a heck of a lot better.

 

[BurnsTACP]

Purchased gauges, pillar pod, and boost controller today. Main hold up will be the pod since it's coming from AUS. Went with AEM gauges. Boost gauge doubles as a controller. Was cheaper than purchasing an MBC separately. Everything should be installed within the next two weeks.