re: performance of computer chip

Submitted: Thursday, Dec 04, 2014 at 00:05
ThreadID: 110334 Views:4501 Replies:8 FollowUps:7
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I have a 2011 200 series twin turbo V8 diesel and I am unhappy with the fuel consumption while towing my 3 1/2 ton van. I drive very conservatively and at best in normal conditions battle to get better than 19 1/2 - 20 litres per hundred.
I am not considering a 3" ss exhaust system because of cost but would like to fit a performance enhancing chip. I've heard various reports about one model of chip being a good deal better than another. Can anyone offer advice as to what brand of chip to get and what the advantages in litres per 100 would be with good conservative driving?
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Reply By: Gone Bush (WA) - Thursday, Dec 04, 2014 at 00:11

Thursday, Dec 04, 2014 at 00:11
What gear do you tow in?

I tow in S4 and that gives best results. Mind you, 19 to 20 l/100kms is pretty good and you shouldn't expect much better. Don't ever tow in Drive, that's the worst thing you can do.

Do you have a Scangauge 2? If not, buy one and set it to show Transmission Fluid Temperature, get that right and everything else falls into place.

In my opinion, and this is bound to be argued, a chip just over fuels and is counter productive.
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Follow Up By: Member - Mally (WA) - Thursday, Dec 04, 2014 at 00:51

Thursday, Dec 04, 2014 at 00:51
Thanks for your input. I will certainly look at getting a Scangauge2.
I have been towing in S5 sitting on 98 klms ph at 1800 revs.
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Follow Up By: Member - Nutta - Friday, Dec 05, 2014 at 17:12

Friday, Dec 05, 2014 at 17:12
Personally when I'm towing I like the revs up around 2200 to 2500 where theres a little more torque.
1800 is just lugging the engine to much imo.
FollowupID: 829003

Reply By: Gone Bush (WA) - Thursday, Dec 04, 2014 at 06:33

Thursday, Dec 04, 2014 at 06:33
Mally, here is a copy of a post I put on the Bushtracker Forum, and on LCOOL (highly recommended Forum):

"I just had my Scangauge upgraded so it could display the Transmission Fluid Temperature (TFT). If you recently purchased a Scangauge it will display TFT after you enter the appropriate parameters, but older ones, like mine, need to be upgraded.

If you haven’t got one, you can buy them here:

The parameters to enter are:
TXD: 07E121D9
RXF: 032100000000
RXD: 2808
MTH: 00010001FFD8

We just spent a few days out in WA’s north east wheatbelt exploring the granite rock outcrops with two other BT owners and I took the opportunity to experiment by driving to keep the temperature of my transmission fluid low.

It is a real education and flies in the face of my long held belief that low revs/tall gear were best for touring, economy and kindness to the vehicle.

Toyota recommends towing in S5. Driving in Sports mode allows the Torque Converter to lock up, given the right circumstances. It won’t lock up in Drive (D).

Now I prefer to drive at about 90kph. If I drive at 90 in S5, the TC will not lock up and the Scangauge shows these approximate figures:
RPM: 2300
L/100kms: 24
TFT: 85 to 90degC

However, if I drive at 90 in S4, the Scangauge shows these approximate figures:
RPM: 2200
L/100kms: 18
TFT: 60 to 65degC

That is a real fuel saving and is being very, very kind to your transmission.

The only way I can get similar good figures in S5 is to speed up to about 100kph where the TC will lock. But I find that uncomfortable touring and it is very hard to keep the TC locked at that speed. Any slight incline or headwind will unlock the TC in S5.

The really interesting thing is that changing down (from S5, TC unlocked, TFT at about 85degC) to S4, you can see/feel the TC lock by the RPM dropping about 200 revs, the TFT readout drops very quickly to about 60degC, within a minute actually. And the fuel consumption improves by about 5 or so L/100kms.

So I think most of my towing will be in S4 from now on, and my Cruiser will thank me for it."

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Follow Up By: Athol W1 - Thursday, Dec 04, 2014 at 09:47

Thursday, Dec 04, 2014 at 09:47
I agree totally with Gone Bush with all his comments, but I also have an added transmission cooler (Making 3 in total) as you can not overcool a transmission, and for every 10 deg that the temp is reduced then the life of the transmission is doubled.

Even with the additional cooler fitted I have seen transmission temps of over 125 deg when climbing some hills (Cunninghams Gap, Brown Mountain, Mombi to name a few).

I consistently get around the same figures when towing my 2.8t van with my LC200TTD, and have seen as high as 26L/100km (Scangauge average for the day) when towing into head winds on the Stuart Highway using S4 at around 95kph.

Definitely no towing in 'D', only ever tow in S5 or S4 and this is determined by the prevailing conditions with one eye on the Scangauge.

Hope this helps
FollowupID: 828932

Follow Up By: Ross M - Saturday, Dec 06, 2014 at 23:07

Saturday, Dec 06, 2014 at 23:07
You can EASILY overcool an auto transmission and most modern auto's WILL NOT change into higher gears or highest IF the temp isn't sufficient to ensure NO slip of plates and proper changing under load is achieved.

Above 60c is best and under that or too cool, moisture isn't displaced and sludge and rust/corrosion will build up.
Too cool is not good, too hot isn't either.
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Follow Up By: fisho64 - Tuesday, Dec 09, 2014 at 01:02

Tuesday, Dec 09, 2014 at 01:02
Gone Bush, I have found similar towing 3.5T of boat and agree
FollowupID: 829277

Reply By: bluefella - Thursday, Dec 04, 2014 at 08:15

Thursday, Dec 04, 2014 at 08:15
A good chip will cost approx. $2000, it will improve performance, but little effect on economy. Those figures are not to bad towing 3.5t. IMHO Unichip is the best and safest available.
AnswerID: 542530

Reply By: Member - bbuzz (NSW) - Thursday, Dec 04, 2014 at 10:12

Thursday, Dec 04, 2014 at 10:12
Hi all,
Does this policy work for a 5 speed auto Prado 3 litre?

I usually tow in D and can on good roads keep the transmission locked. Roads eg like the South Coast from Sydney tax any transmission so I suppose I should use 4 there.

My consumption is OK, around 13 to 14 towing 1800kg van. I have a Landcruiser Transmission cooler fitted. (bigger capacity).


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Follow Up By: Athol W1 - Thursday, Dec 04, 2014 at 14:40

Thursday, Dec 04, 2014 at 14:40
In answer to your question the answer is a resounding YES. It is not revs that are not excessive that will kill you vehicle but heat will. The cooler that you can keep your engine the better, provided that it has reached a normal operating temp that is governed by the thermostat, and for every 10 deg that you can reduce the transmission temp you will double its life.

Toyota do not recommend towing in D.
FollowupID: 828943

Reply By: The Bantam - Thursday, Dec 04, 2014 at 13:15

Thursday, Dec 04, 2014 at 13:15
If you have grown up with petrol engine pre-conceptions a lot of things about driving a diesel will seem strange.

In may ways the behaviours could not be more different.

Diesel engines operate most efficiently arround where the power and torque curves cross....this is where the engine develops the maximum torque and the maximum power possible both at the same time.....they will both drop away shortly after...... and this is regardless of manual or automatic gearboxes.

I don't know that it is for your engine but for my small 4 cylinder that is around 3000rpm.

OH and...with turbo diesels this band will be narrower than it would be for a similar AN diesel.

If the manufacturer of the vehicle is half smart they will have matched their transmission with this behaviour....and generally toyota are pretty good at this.

In a diesel lower RPM does not necessarily mean better fuel economy.

There is a very good reason most diesels come with a tacho.

If you listen to the engine it will tell might be heavy rock and roll, but it should be a happy song.....if it sounds like a durge it wont be running efficiently.

By all means look up the torque and power curves for your engine.
Watch your EGT
Get that scan guage and watch your tranny temp.

But above all listen for the song

the differences.
with a petrol engine

pushing for the most power, you will hold in a gear till the engine will not comfortably rev any harder till you pick the next gear and you will keep the revs high

Pushing for most economy you will run the highest gearing the engine will tolerate and keep the revs low. in all cases.

With a diesel engine

Pushing for most power, you need to keep right on top of that power and torque curve.....maximum power will not be generated below that band and power will drop off above that band.
You should shift to the next highest gear as soon as the vehicle will pull well in it.

Rev'ing out beyond the power band achieves little.

Maximum economy will occur at two places in a diesel rev range.....

lightly loaded with light throttle application right at the bottom of the power band.

Heavily loaded toward the upper end of the power band where the torque and power curves cross.

OH btw if anybody tries to say their diesel has a fairly flat power curve.....they are kidding themselves......most have less than 50%to 70% of their maximum power a thousand reves either side of the peak.

Ya gota keep on that curve.

AnswerID: 542537

Reply By: Member - mark D18 - Thursday, Dec 04, 2014 at 18:55

Thursday, Dec 04, 2014 at 18:55
Fuel figures Sounds about right to me. You are towing a fair bit of wait
I don't know how fast you drive , that's the biggest benefit to getting good fuel figures.
I would leave it standard and save yourself a heap of money.
Toyota put a lot of money into developing these vehicles .
Seems like a lot of money to me for little gain.
The after market companies must be rubbing there hands with all the gear people who want to save a km or two on fuel consumption.
Great vehicle bog standard.

AnswerID: 542548

Reply By: DaveO*ST-R - Thursday, Dec 04, 2014 at 19:51

Thursday, Dec 04, 2014 at 19:51

I have a 20' full size van weighing 2.5T gross and with my LC200 (diesel) the best I have got is about 18 LHK. So for 3.5T, I think you are doing fine at 19.5 - 20 LHK - depending of course what speed and gear you tow in. As much as the LC200 does it with ease, you are in essence towing a serious weight that is a brick on wheels !!

I have the view that it is what it is, within reason of course. For the cost of a chip at say $1500, you can buy a lot of diesel for that !! I cannot help with what fuel "savings" you may or nor may not get with fitting a chip, as I do not have one on mine. I recently had fitted a (manually operated) torque converter lockup switch to my vehicle which is said to improve consumption when towing up to around 2 LHK dependent on a few variables. I have not tried it whilst towing as yet, but a recent trip to SA and back using the TC lockup switch in 100 zones sitting on 100 with cruise control on as much as possible saw consumption at 11.5 LHK - the best I have achieved to date - and my car has quite a few accessories on it to hinder good fuel consumption - bullbar, winch, suspension upgrade, non standard tyres, roof bars and basket etc. There are plenty of opinions on TC lockup switches, but as they say, opinions are like ......, everyone has one !! Food for thought though.


AnswerID: 542551

Follow Up By: DaveO*ST-R - Thursday, Dec 04, 2014 at 20:08

Thursday, Dec 04, 2014 at 20:08
I forgot to add, the main reason I fitted the TC lockup switch was not for fuel consumption, rather for a reduction in transmission temps. The lower fuel consumption comes with the lower revs when the TC is locked and not jumping all over the place between gears with the TC continually locking and unlocking. (FYI, I tow predominantly in 4th gear, occasionally shifting to 5th on the flat or downhill)

The difference in temperatures b/w the transmission being locked or not is considerable - much better for the transmission when considering longevity etc etc. As said previously, if you do not have a Scangauge II, or an Ultragauge, something that is capable of showing transmission temperatures, get one. They are invaluable.
FollowupID: 828959

Reply By: Mick O - Friday, Dec 05, 2014 at 07:21

Friday, Dec 05, 2014 at 07:21

just a word to the wise on chips. You'll need to give careful consideration to they type that you fit considering you are not fitting other mods that go hand in hand with such a device (like an exhaust or EGT guage).

The standard plug and play type models simply dump more fuel into the motor be they fuel rail or injector pulse type. You would need to be looking at an integrated model which means a good nit of time on the dyno setting the chip up for your specific purpose. This may just save your motor when towing that 3.5 tonne load in difficult conditions like hills.

I'd very much recommend that should you go down that path, consider fitting a larger exhaust and dump pipe accordingly. More fuel will mean more heat and more exhaust gasses and they have to go somewhere.

I've been through the process with the 4.5 T/D in my 79 series and the results were outstanding, more in power gains than economy though. Results are in the blog a fair way down the page.

Building the off roader

All the best for the festive season and 2015.

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trip would doubtless be attended with much hardship.''
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