cachaciero

The theory is fine however try to apply it consistently on the M25 / M4 🙂

Bit late to this topic and what I will have to say is based upon my experience with an RX400H. IMHO the bit that needs re-mapping is the gearbox / electric motor controller. The 450 motor is unlike the 400 already tuned for economy, now given that on a reasonably cross country run mixed motorway / A roads I can see 32- 34 I would have thought that the 450 would be able to get 35-38 on the same journey and maybe better driven to the cars strengths. However the bit that will kill the mpg figures on the 400 is Mway driving, the fuel consumption drops of a cliff at about 65 and driven hard will soon dip to sub 30mpg, I don't understand why the cut off point is as marked as it is, drag force will increase in proportion to the square of the speed so I have to assume that being a draggy square box the extra 5mph between 65 and 70mph is enough to significantly increase the aerodynamic load at that point. However there is one other issue that takes its toll on motorway driving. Imagine driving in a file of cars all doing nominally 70 but slowing up to say 60 and then accelerating back to 70 and then decelerating again (M25 scenario )- Now my 400 decelerating from 70 will often require a touch of brake to get the speed down to an acceptable level in the distance available under these circumstances I will often put it into B mode thus increasing the deceleration and getting a little extra into the battery, as the stream speeds up back into D and touch the throttle, now I don't require much energy to get back to 70, the battery is well up and there is more than adequate electrical energy available to restore speed but the moment you touch the pedal the IC engine springs into life, burning petrol which does not need to be burnt, because a minute or two later you are having to slow again and this really pi???? me off. That is the one area where my gut feel is that the software really needs a bit of re-working. There appears to be little sensible relation between speed, torque demand (pedal position) and battery power' Unfortunately with no access to logic flow diagrams let alone source code it is near impossible to do anything. Someone with the requisite tools and knowledge could probably re-constitute the code but that would require a lot of enthusiasm or money and as we are not talking about races to win on a low volume production vehicle there is little chance of either happening as far as I can see.

As far as I can see the GS450H is in terms of drive train / HV battery is little different to any other Toyota / Lexus Hybrid and overall HV battery failure is very low so what is different about the GS450H? what is "a high number of people with battery issues" ?. I suspect that at a battery module level the modules are identical over the whole Hybrid spectrum, the only thing that appears to change is the number of modules in a battery pack and hence the final voltage. When I purchased my first Hybrid a Prius 2 battery and ability to repair / replace was a concern and I did a fair amount of research on this and came to the conclusion that it was no big deal to repair a HV battery pack, I believe pretty well any second hand HV battery should be a source of usable individual modules, Toyota seems to like to keep things standard across models and generations as far as possible and I believe that this will apply to batteries as anything else, however this is unproven and I would be interested if anybody knows for fact that this is not so. The only problem I can see with building / refurbing an HV battery pack is charging it on the bench and ensuring that all the modules are at a similar charge state before use this is improtant. In the event until now I have had no reason to explore this scenario further both the Prius and Lexus just work and the occasional check with an analyser would indicate that there is little deterioration from new in the individual battery modules on either car. NiCad batteries providing that the charge / discharge regime is controlled within limits are virtually indestructible, in this respect the Toyota setup does control the battery charge / discharge regime very conservatively, actually too conservatively IMHO. 12 V battery is another story :-) Friday at 09:44 AM 19 replies

Have a trawl through e-bay though knowing what the OEM part number was would help.

Thanks for that and the reference to Toyodiy some interesting reading there. Rgds Tony

Does no one know the answer... ?

O.K it doesn't work the way I believed it did, have to say I am a little surprised, it aint logical :-). The next question is what are the o/p volts 12V....5v or something else and what is the switch? straight forward electrical contacts which may handle enough current to drive a relay or an optical or other semiconductor O/P which may have very limited current drive capacity, hooking a relay coil straight onto such an output could have disastrous consequences. Bit more info required :-) Regards Tony.

Please! Please! don't ever think I have superior knowledge on anything and least of all the Lexus which I have only had for six months :-) I don't even have a complete set of schematics and none of the Training Material which I am sure is available to their Techs. Currently for areas of interest I have to go onto the Lexus Support site and wade through bits of that trying to find info on the things which are of interest. So far I have not had a need to look in detail at the gear selection side so I don't have all the info on this area of the car. As regards the gear selector something I saw / read somewhere makes me believe that it works the way I said it does BUT I could be wrong. The gear positions are displayed on the instrument panel and for sure that data comes from the network, doesn't mean to say though that there isn't a discrete wire for each position directly from the gear switch though I can't see why they would need to do that. If you like send me a copy of the schematics you have (saves me time and money!) and I will have a look and tell you what I think. However my gut feel is that is that it will be easier to purchase one of the available decoder boxes that hook onto the can bus and give the discreet outputs you require, prices seem to range from about 50 to 150.00 depending on the number of outputs. Out of curiosity why don't you just use the switch to disable the front sensors? regards Tony

A relay connected to D ...(rive?) you might have a problem doing that I would have to go back and delve into ,the wiring but pretty sure that the Gear Selector is it's own ECU connected to the CAN bus so there will not be anything to connect to :-). Tonyd

Indeed :-) Unfortunately this site does not appear to e-mail me reliably with updates

Could not agree more, the only car black is good for is a Hearse the occupant being long past caring about being kept in an oven. Tonyd

My personal view about Hammerite is not very positive, never had much luck with it, yes you can paint it over rust but then you can paint lots of things over rust, the biq question is how well does it contain it? in my experience not very well. There are better and more long lasting solutions to rust. My preferred technique is to mechanically remove as much rust as possible then wash with water containing a salt neutraliser. Then paint / spray a conversion coat, the kind that goes blue/black when it's dried, finish with a coat of epoxy primer they are not so difficult to work with as you might think, it sticks like the proverbial even to poorly prepared areas and once cured is hard and totally air and water proof. More complicated than going down to Halfrauds and buying Hammerite of the shelf but a much better job and you won't have to do it again in a year or so. Your initial outlay in material will be more expensive but the materials do not markedly deteriorate with time and the next time you find a bit of rust you will have everything to hand.:-) For anybody working on cars dealing with rust cure / protection I would strongly suggest a visit to www.rust.co.uk their online site and printed catalogue is informative and they can supply all the products I have referenced. I have no connection with them other than as a satisfied customer. Fe-123 from the same company may also be worth considering if mechanical cleaning is difficult due to access. Tonyd

That is exactly what I meant, find it very annoying to find a thread that touches on a problem I have and then it just ends with no conclusion, was the problem fixed? what fixed it? or did it just disappear as sometimes happens. Tonyd