lexus v8

[TheoM]

Good idea Laurence ! Maybe start a new thread even ? What are your diff ratios and who did your tuning ? Is your's the VVTi ?

[larry007]

Good idea Laurence ! Maybe start a new thread even ? What are your diff ratios and who did your tuning ? Is your's the VVTi ?

Being a noob with zero posts on the forum, I am bit reluctant posting, especially as a non-Hilux pilot with very limited mechanical capability

I don't have the VVTi, extra power wasn't required and costs were considered at the time... Currently I have 187.3kW and 356Nm, which is justabout spot on for these engines. KSD in Stikland dyno'd it recently for me and I have tinkered with the basic cold start and acceleration settings to suit me better (keyboards are more my thing). Very happy with smooth power delivery and nice torque curve from low rpms.

Regarding the diff ratio's, it a 4.9 / 29-spline normal Pajero 2.8 slip-diff, also in play, the original Gearbox and transfer case. With the original diesel box, 1st gear is short, so it help the 1.9transfer case. The Pajero is a great overlander, not a hardcore Jeep, or dare I say, Hilux It performs great in the dunes, but has limitations in cross axle twisties, but its fine for our use (family of 6). Obviously being an overlander, extra millage gained through correct driving style/speeds would be most welcome.

[TheoM]

Being a noob with zero posts on the forum, I am bit reluctant posting, especially as a non-Hilux pilot with very limited mechanical capability

..............nice torque curve from low rpms.

.

In that case then I am also disbarred from posting :razz: However I have found the guys around here to be very accomodating and helpful. My interest is the fact that I am on 33' tyres with H55F cruiserbox and TC but with 4.1:1 ratio and I am thinking that 4.56:1 ratios will be better ?

Just how good were those low RPM torques ? Got a chart ? My findings have been that alot of 1UZ 4x4 critisism should be laid before the tuners.Most of them tune for race cars at high rpms and do not bother about low rpm tuning.If we could get a good tuner to focus on the 4x4 market he would probably make an absolute killing !

[larry007]

Being a noob with zero posts on the forum, I am bit reluctant posting, especially as a non-Hilux pilot with very limited mechanical capability

..............nice torque curve from low rpms.

.

In that case then I am also disbarred from posting :razz: However I have found the guys around here to be very accomodating and helpful. My interest is the fact that I am on 33' tyres with H55F cruiserbox and TC but with 4.1:1 ratio and I am thinking that 4.56:1 ratios will be better ?

Just how good were those low RPM torques ? Got a chart ? My findings have been that alot of 1UZ 4x4 critisism should be laid before the tuners.Most of them tune for race cars at high rpms and do not bother about low rpm tuning.If we could get a good tuner to focus on the 4x4 market he would probably make an absolute killing !

I wouldn't comment on diff ratios, bar that my understanding is that the higher the ratio, the longer each gear becomes. The general consensus on this topic seems to indicate that the sweet spot exists somewhere between 2700-3300rpm. Higher speed causes higher wind resistance, this obviously also has a direct effect on fuel consumption which must be taken into consideration. For me, my cruising ave of 105-110km/h, is adequate. I believe one should decide on your cruising speed and try and get to the magic rpms for your final drive. Personally I felt that the engine didn't really perform nicely under 3000rpm, could have been due to previous maps. And running 3400rpm was too high.

My dyno graphs looks exactly as the ones seen on PAGE2 on this topic, with the little hump included...
Torque: 320nm on 2000rpm, maxing at 4500rpm with 356nm (a lot available from low rpm, with little climb to max overall)
Power: linear climb up to 5300rpm-ish, dropping rather fast
Maximum power drivability rpm: 4500-5300rpm

On tuners, that's another topic altogether and I still understand too little. Theoretically Spitronics fuel maps should allow for sedate driving - fuel map lean, normal driving - stoich, fast cruise - richer, WOT - burn fuel. From my understanding, the tuners do set the WOT first and tune as best possible from there on down, setting each map on the dyno. Realistically, a lot of time would be required to verify each map through the rev range. As a DIY, checking each of those maps and ensuring you have no pings, you'll need a Wide Band sensor, look out on the timing, all whilst driving and verifying you stay within each fuel map.

So from my acknowledged little understanding, I would say when doing a 4x4 trail, your motor is doing low RPMs, and you are lazy with the throttle. Thus, your LOW maps are normally more tuned to run leaner to save fuel, but this may not be required whilst doing 4x4. THIS IS MY LIMITED OPINION. 4x4 may require to rather have a different LOW map with fuel and timing settings tailored for doing 4x4, and upload as/when needed. However, every tuner will state that a well tuned map will work everywhere, which in my case now, I would concur compared to my previous map. (Sjoe, told you that should be another thread). I would be open to other opinions or facts on my understanding.

So with your 33", what is your cruising speed? and the rpms at that speed? and consumption?

[TheoM]

Thanks !

..So with your 33", what is your cruising speed? and the rpms at that speed? and consumption?

Not sure what my consumption will be from now on because a buddy and I discoverd 2 evenings ago that my TPS was not calibrated :wth: Now that it is, were are going on a trip this weekend so we will see but I do expect a change.In general at 120 km/h I am at about 2500 RPM in 5th and get @ 6km/l - 6.5km/l. When I tow my loaded Metalian Midi trailer in 4th at 110km/h -115km/h at about 2700 rpm I get 5km/l.My gearing is very long though.On the dyno they had to use 3rd cos 4th just becomes scary.- I have seen 137 km/h in 3rd on the GPs and there was still throttle left ! I am thinking of 4.56 ratios to shorten the legs(and reduce the load on the drivetrain) and I could then also go to 35" tyres.

[larry007]

Thanks !
In general at 120 km/h I am at about 2500 RPM in 5th and get @ 6km/l - 6.5km/l. When I tow my loaded Metalian Midi trailer in 4th at 110km/h -115km/h at about 2700 rpm I get 5km/l.My gearing is very long though.

Wow, those are loooong gears And I thought mine was bad... It would be most interesting to see what the difference in consumption would be if you were to drive @120 in both 4th and 5th. I would also think that you would like to get your gearing sorted to get the revs up a bit. My gut still says 3000-3200 will be best, if only someone can share their experience with us

PS doing 130 in 3rd at 5500rpm for fun and then putting your foot down - that is nuts!

Enjoy your trip!

[TheoM]

PS doing 130 in 3rd at 5500rpm for fun and then putting your foot down - that is nuts!

I see I am not alone