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02 With lexus gearing issues

Posted: Wed Sep 20, 2017 9:24 am
by WCKD
Hi Guys

I am new here and this will 'soma' be my intro if you don't mind.

My name is Landre and I am live in Port Nolloth at the moment. I am not just new to the forum but new to the entire 4X4 game. Only recently bought a 4X4 and obviously it had to be a Hilux. This is my 3rd vehicle and also the 3rd one to be modified. But instead of doing this one myself I decided to let someone else pay the school fees for a change and got this already modified.

I got myself an 02 D/C 4X4 Hilux with a first generation Lexus V8. It came with ARB front and rear bumper with rock sliders and a roof rack. I got it in February love every minute of driving this thing. It pulls really solid and that sound is just awesome. Fuel consumption is not to bad at 5km/l on my trip from Cape town to Port Nolloth, but I think it can improve and this also bring me to my question. It seams when they did the conversion they used a 3000D with the 5L engine because @120 on GPS the RPM is @3400. Now I've read a lot around this and it seams my diff ratio is 4.88? I know GRWLR had the same problem and was looking at KZ-TE diff but never said if he got his fixed. Any suggestions on how to get the revs down a bit? Looking at 2500rpm to 2800rpm on 120km/h would be ideal. Also here are some pictures
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Re: 02 With lexus gearing issues

Posted: Wed Sep 20, 2017 10:15 am
by Mud Dog
Welcome Landre! :thumbup:

Yoh! 5km/lit on the open road is hopeless - you should be getting at least 8 or 9 with a V8.

I'm not sure what the difference in ratios are (if any) between the KZ and 5L boxes. First step would be to check that out. Then you might need to change the bell and clutch as well ... could become a costly exercise. Changing diff ratios is also a pricey route because you have to do both of them, but it may be the better option IRO cost.

You could also consider fitting bigger diameter tyres, but that brings a whole host of ills along with it besides straining the drive-train (you would probably have to do a body lift or suspension lift to accommodate the bigger wheels and both have spin-off mods that have to be addressed).

The closer to the motor you are able to change the drive ratio, the less strain there is through the drive-train. So if you have a good gearbox specialist in your area, he could advise on the availability of gear ratios that can be fitted to the existing box. That's another option if possible on your box.

Re: 02 With lexus gearing issues

Posted: Wed Sep 20, 2017 11:23 pm
by LouisZ
Your diff ratio should be on the OE diesel setup eiher a 4.55, 4.11or the scarce 3.72. The 4.88 should be at 3300rpm at 120km/h? Where any other lower diff ratio should be lower rpm at 120kmh. But depends on tyre size too.

Seems if the the diff ratio could be 4.88 :think:

The lexus will be better on a 4.5 or 4.1 ratio.

Re: 02 With lexus gearing issues

Posted: Wed Sep 20, 2017 11:35 pm
by Thabogrobler
Dtandard Kz diff ratio's are 3.73 AFAIR but you will need the Kz box as I don't think the 5L box will last long behind a Lexus.

Personally, I would leave the diffs as is and tyre up - either 33 or 35's!

Re: 02 With lexus gearing issues

Posted: Thu Sep 21, 2017 8:51 am
by WCKD
Hi Guys

Thanks for all the reply's and ideas. Seems the bigger tyre size is a favourite here. Unfortunately it is not an option for me at this stage as I do not have any space to work with. The roof rack only clears the garage door by about 20mm and since I'm only renting the place can't really get the door made bigger.

I asked about the diffs because there is an KZ here that has been rolled and I might get permission to swop out the diffs with mine, just waiting for the person responsible to come back from leave. All that it will cost me is a bit of time.

In regards to the gearbox it has I have no idea. According to the previous owner a kz was used in the conversion but that's all third hand info as he did not to the conversion but bought it finished same as me. Is there any way I can check to see what box was used/installed. I would like to know because I can always ask to swop the box as well if the 5L box stayed in there.

Re: 02 With lexus gearing issues

Posted: Thu Sep 21, 2017 3:46 pm
by Thabogrobler
Post a picture of the gearbox, we might be able to id it.

Re: 02 With lexus gearing issues

Posted: Thu Sep 21, 2017 5:07 pm
by Mud Dog
If you can swing it to swop out the diffs, that might just be all you need to do. Just make sure of the ratio that you have vs the ones you want to swop. The diff housing usually has the ratio on the outside, but this is unreliable in many cases where rebuilds and conversions have been done. The number of teeth should be stamped into the crown wheel and also the pinion (otherwise physically count them) - divide the bigger number by the smaller one and that will give you the ratio.

Re: 02 With lexus gearing issues

Posted: Fri Sep 22, 2017 8:10 am
by Stef
Hoe kry mens 'n Lexus se consumption reg?....Jy LIEG hom reg :D:

KZ Surf's gearbox works just fine on the SFA with its diffs (petrol ratios)...revs more or less the same as what you have. At a stretch it will give 7km/l but tows like a dream.

Proper bell housing with normal KZ box, D4D clutch is the way to go apprently, and diesel diff ratios should drop you rpm's.

Re: 02 With lexus gearing issues

Posted: Fri Sep 22, 2017 12:11 pm
by Willem van Schalkwyk
Hahahahahhha Stef dis die selfde met die V6 en die 2.7! :laugh2:

I would do the bigger tyres first and then the diffs if needed after that.
If you first do the diff ratios and then bigger tyres you might sit in the same situation.

my 2c

By the way....nice van!!