history is full of engines where they got it wrong so i would not trust the manufacture, but also why you don't tune engines that have known issues.
a lot of engines are well designed enough that you can increase the power a lot, if you know what needs to be done. not uncommon for guys to get double, triple, the power out of an internally stock engine. it depends on how far do you want to go and what will it take to keep it reliable.
mechnificent,
Jan 6, 6:31pm
So tell me about the egt.
tweake,
Jan 6, 6:32pm
i don't think i have heard that one before and it sounds like BS. if you make the injection to long it can cause piston burn but advancing the timing to much is equally bad. your better to do the correct timing and increase injection pressure and flow rate (bigger injector).
tweake,
Jan 6, 6:34pm
fine if you keep afr's reasonable and enough air flow (boost) for cooling. a lot of that comes down turbo tuning and intercooling.
tweake,
Jan 6, 6:36pm
of course. but funny enough thats not usually where they fail.
mechnificent,
Jan 6, 6:38pm
Yeah it's burning too late in the cycle that causes high egt. too much fuel or not enough advance.
mechnificent,
Jan 6, 6:39pm
Keep us posted how it lasts.
mechnificent,
Jan 6, 8:20pm
Oh ?
tweake,
Jan 6, 8:22pm
from some that i know of, longer than most people keep their cars. one i can think of (tho older model) thats putting out well over double the factory HP on stock head/block. even my own i've had for 8 years. atmo diesel with turbo added. many people said it would blow up. its still running perfectly fine. chipped work ute that hauls loads, lots of fully loaded trailer towing. still good and egt's are low.
if done right they last perfectly fine. most problems are because they are done poorly.
tweake,
Jan 6, 8:27pm
egt is heat from the fuel minus the cooling.
retarded timing causes higher egt because your pouring in extra fuel to compensate for the lack of power caused by the retarded timing. ie egt is higher than normal when driving, and so is the fuel usage.
s_nz,
Jan 6, 8:32pm
The reason you can gain substantial power & economy via re-chipping diesels is that the factory tune essentially uses more fuel, and gives up power to keep emissions (partially oxides of nitrogen) at allowable levels.
By allowing Oxides of nitrogen in the emissions to exceed allowable level's, both power and effichency gains can be had. This is what VW had their "dieselgate" cars do. Unless the cars detected they were being lab tested, they would run run an "alternate" tune. Unsurprisingly they quickly picked up a reputation for offering good drive-ability and lower real word fuel consumption compared to peer diesel cars that didn't cheat on emmisions.
The above is why re-chips are banned in NZ without LVV certification to prove that emissions haven't been worsened.
So yes, but gains can be had. But as allways, more power & torque means more stress in the driveline, and the temptation exists for the programmer to excessively crank the boost pressure. Will lead to initially happy customers, but puts the engine under a lot more stress.
tweake,
Jan 6, 8:45pm
does LVVT have to keep to an emission standard? mine hasn't and i'm pretty sure there is a ton of worked v8's running around that will never be close to factory emission standards. afaik, please correct me here, that its more about making sure the extra power is "safe" ie braking is adequate, mounts are suitable etc.
but quite correct that mild gains are to be had by defeating emissions.
but i'll argue about the stress put on the engine. most decent engines will handle a lot more IF its done correctly. the problem is thats its very easy to make tune thats more than the rest of the engine can work well with. ie it needs a different turbo, bigger injectors, better intercooling etc. thats the choke point for a completely stock engine. eg to much fuel means high egt's but also excessive turbo back pressure which increases egt's, increased boost can heat soak the intercooler so inlet temps go up which not only increases egt's but also acts like timing advance. that all combines to make excessive egt's especially when under load for long lengths of time.
s_nz,
Jan 6, 8:59pm
Actually I am not sure what is involved with getting a Chipped vehicle LVV certified, or if it would pass. Just assumed the process wouldn't be worth it for most.
That said, Section 2.6(1) of the above requires an emissions test of post 2008 vehicles, but that emissions test is a pretty crude o2 meter, rather than measure NOx that is more relevant in diesel emissions.
For other engine mods (I assume like a bolt in high flow catback exhaust, high flow cold air induction system), they can been deemed "minor" if they meet a lot of criteria, including a total power increase of not more than 20%.
But chipping / returning of a turbo engine is specifically excluded from being a minor mod, hence allways requiring LVV certification. I assumed the reasoning was emissions, but I could be wrong and that the concern is something else like excessive power gain meaning the car could do with bigger breaks.
tweake,
Jan 6, 9:07pm
pretty sure its more about power, or more to the point about the ability to increase power above the threshhold. this is where i got stung a bit because if i used the stock electronic injection pump and factory ecu i would have been ok, but because its mechanical injection which is easy to wind the fuel up it required a cert. (this is combined with minor motor upgrade).
if your spending a say $2k+ on remap or tuning box, a $500 cert is not a whole lot extra.
mechnificent,
Jan 6, 9:10pm
When you put your foot down, the timing isn't retarded, fuel's just put in for longer, and is burning later in the stroke. That gives it more time to soak heat into the block and also go out as high egt. If the timing is tuned slightly advanced we can inject the same amount of fuel while it's still under greater pressure and it burns quicker and we get more power out and less egt. Quickest easiest way to make a diesel run crisper and with more power is to advance it slightly. Setting them retarded makes them run hot, just like a petrol does. It's the burning late in the stroke that makes high egt, whatever the cause of the late burning.
skiff1,
Jan 6, 10:41pm
why can’t it be both?
mechnificent,
Jan 7, 7:08am
Powerful, economical, cheap and reliable quality. Don't see a problem.
tweake,
Jan 7, 6:33pm
i think your mixing up a few different things. timing is the start of injection. length of injection is a different ball game.
you can advance timing, if there is head room to do so. again it depends, some engine run really good timing and advancing it causes loss of power and failure. others run retarded timing for emissions purposes so they can be easily advanced back to normal. but some run advanced timing to counteract ignition delay caused by egr. some will vary depending on if they run hot or cold egr. its not as simple as "we just advance the timing".
but also you can't advance timing enough to make up for the extra length of injection on a sizeable increase of fueling anyway.
regy_2005,
Jan 7, 6:54pm
Recently purchased a Hilux with rechip and tuning box bit worried now after reading this thread. If I disconect the wiring would it need retuning or be ok asis?
sw20,
Jan 7, 6:55pm
Because you look really silly on Monday morning saying you can't travel to the worksite because you blew the engine on Saturday night.
mechnificent,
Jan 7, 7:17pm
I know the differences Tweake. Started in a truck shop, then worked all my life in the country and on road building equipment. Overhauled pumps and tuned diesels.
You must have seen the egt go up fast when you floor it up a big hill. Throttle off and it goes down fast too.
I agree we can get more power, because all manufacturers are tuning for chumps that might inadvertently overload things. But hotting them up reduces that safety margin. it makes them easy to blow. and increases the loads, and in the case of diesels, the temps a lot.
mechnificent,
Jan 7, 7:21pm
And do you fit over sized plungers in the pump do you. like my mech son. He's done some mad ones. haha. on old L toyotas.
Now he's got a common rail triton and doesn't bother any more. It goes like stink he says. and they do pull at all revs really nicely. can't beat the new developments.
tamarillo,
Jan 8, 9:06am
Many new engines come in various states of tune. We can buy same car and same engine with different outputs. If manufacturer is giving journos correct information then sometimes, at least, there are no other changes. Indeed I recall one magazine suggesting the base model with least luxury features and lowest powered engines was the Best Buy in the range when the lost power is regained aftermarket. I’m not a mechanic, and hear the warnings of trying to get more than manufacture wanted out of an engine. But it seems sometimes a remap can keep it within limits. My bike has a remap to suit its locally made pipe, it’s 100% reliable with high mileage now.
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