richardg
Admonishtrator
Interesting idea.....I will look into that
Car remapping
- Thread starter richardg
- Start date
richardg
Admonishtrator
I'm pretty steady these days, so even if my remap is making 300bhp and could knacker the motor, I'm hopeful it won't be under my watch
Tony Lockhart
Avoiding Stress, at Every Opportunity
I’d love to see a rolling road dyno print-out for this.
A very relevant post on PistonHeads, where the subject of different power output from the "same" engine within a manufacturer's range was covered by someone who claimed to be an Engineer working for BMW in their engine development section. The postee didn't give his name etc. So its up to you if you choose to believe what he wrote without being able to verify his credentials. I was convinced by the case he made and way he explained it. I don't work in engine development, but I am a practising Engineer with a mechanical engineering degree. It went like this:
BMW have a standard combustion chamber design. It represents their latest state of the art within budget constraints etc for a mainstream production car. Its standard in terms of geometry only. The number of such chambers varies with engine type, 4 cylinder vs 6 cylinder for example. BMW then produce three power outputs for that chamber. Hence multiples of the number of cylinders and choices within the three power output levels give the various engine permutations on sale.
The postee then went on to explain that BMW employed different materials and manufacturing techniques for various engine components according to which power level application the cylinder is to be. For example the highest power output derivative would use forged pistons instead of the cheaper, weaker cast pistons used in the lowest power variant of the cylinder. I think he also mentioned smaller details like piston ring design varied with power output, mainly to deal with heat dissipation, the higher power output engine has more waste heat that needs to be managed. These upgrades are deemed necessary by BMW in order to provide an engine that lasts an acceptable lifespan at the power level at which it was manufactured to deliver.
Since these material and manufacturing method changes don't affect air and fuel flow into the cylinder they do not have a limiting effect on power output. Hence he explained, this is why tuners can replicate the highest power outputs on the lowest power output derivative of an engine. However he did caution that the mechanical design of the lower output derivative of the engine did not have the capability of providing higher power outputs over the same service life as the higher output engine.
BMW have a standard combustion chamber design. It represents their latest state of the art within budget constraints etc for a mainstream production car. Its standard in terms of geometry only. The number of such chambers varies with engine type, 4 cylinder vs 6 cylinder for example. BMW then produce three power outputs for that chamber. Hence multiples of the number of cylinders and choices within the three power output levels give the various engine permutations on sale.
The postee then went on to explain that BMW employed different materials and manufacturing techniques for various engine components according to which power level application the cylinder is to be. For example the highest power output derivative would use forged pistons instead of the cheaper, weaker cast pistons used in the lowest power variant of the cylinder. I think he also mentioned smaller details like piston ring design varied with power output, mainly to deal with heat dissipation, the higher power output engine has more waste heat that needs to be managed. These upgrades are deemed necessary by BMW in order to provide an engine that lasts an acceptable lifespan at the power level at which it was manufactured to deliver.
Since these material and manufacturing method changes don't affect air and fuel flow into the cylinder they do not have a limiting effect on power output. Hence he explained, this is why tuners can replicate the highest power outputs on the lowest power output derivative of an engine. However he did caution that the mechanical design of the lower output derivative of the engine did not have the capability of providing higher power outputs over the same service life as the higher output engine.
Tony Lockhart
Avoiding Stress, at Every Opportunity
I think generally with turbocharged petrol engine tuning, it is possible to achieve a high power figure by having a boost spike somewhere in the rev range. This figure might only be for a few hundred RPM, but it’ll grab the attention of potential customers. On the road, in the real world, that figure is meaningless with regards to performance, and could well make the car worse to drive.
Turbochargers have improved over the last few years out of all recognition, and engine management systems are in a different league too.
But, modern low pressure turbochargers aren’t going to flow the air required for proper, autobahn crushing performance, they’re too small. You don’t want the incoming air trying to go supersonic. Simple as that. It’s a limiting factor. So these remappers try to achieve the power figures at lower engine rpm by going mad with the boost.
Something has to give.
Turbochargers have improved over the last few years out of all recognition, and engine management systems are in a different league too.
But, modern low pressure turbochargers aren’t going to flow the air required for proper, autobahn crushing performance, they’re too small. You don’t want the incoming air trying to go supersonic. Simple as that. It’s a limiting factor. So these remappers try to achieve the power figures at lower engine rpm by going mad with the boost.
Something has to give.
I suppose that the remappers work on the principle that 99% of these cars will be used only on public roads and the massive boost will only be needed for a few seconds before the driver runs out of road (or talent) so they will take their foot off and allow things to cool down a bit. If this halves engine life from 200k miles to 100k miles, most drivers won't care because they never get there. I've only taken 2 petrol engines to over 150k miles, both natasp and cooking levels of power output, The Cav That Would Not Die had a 2L engine and it was absolutely perfect at 155k miles (the same at >200k miles at the hands of its next owner!), while The Indestructible Mondeo, a 1.8, was starting to consume oil and lose a bit of performance at the same mileage.
Like Rich here, the modders are going to buy them at <50k miles, keep them a couple of years, give them the abuse and then trade them in at 80-90k miles with the extra boost removed. The next owner will pick up the extra wear and tear.
gez
pfm Member
So in essence because the fundamental design of the engines are identical, (bore/stroke, rev limits, combustion chamber shape, compression ratio etc), the fundamental power output of the engines in different car models are determined solely by the ECU and how it maps various things (boost pressure for example) and all the changes that are made to the more powerful engines are nothing to do with gaining more power, but only to ensure the engine can cope with the extra power. Logically it makes sense, but as you say there's no way to prove it without knowing the credentials of the poster.
After all you could easily build an engine that was "turbo ready" in the sense it had suitably low compression ratio, strong enough pistons/con rods etc, to take being boosted, and it would run just fine* without any turbo at all and produce a given amount of power. Stick a turbo on it with mild boost (under what the engine internals were designed to cope with), map it to allow for the turbo, and it would make more power, same again with a moderately boosted turbo, and so on. The ultimate limiting factor would be the strength of the engine internals and the size of the inlet/outlet ports & valves.
*As long as it's being fueled properly and not expecting to have a turbo on it.
Hmmmm it would work as you describe, but........such a low compression engine, ready for a turbo to be fitted would be pretty poor without the turbo. Fuel consumption, power and torque would all be very inferior to an engine of the same capacity but with a compression ratio optimised for normally aspirated induction. I've never heard of a company doing this and can't imagine why one would.
Tony Lockhart
Avoiding Stress, at Every Opportunity
The non-turbocharged engine would produce too little power, and be overpriced. It wouldn’t sell.
When I had a VW Bora with the 130bhp TDi engine, I had people tell me their lower rated engine was the same as mine except for the ECU because theirs would remap to 130bhp. But, I would reply, mine remaps to 170bhp. And that was limited by the clutch. And the 150bhp engine would remap to about 190, as it had a few differences here and there.
What it all comes down to is trying to find out what you might be letting yourself in for before buying. No manufacturer or remapper is going to cough up for a new engine if piston crowns melt, I can pretty much guarantee that.
I would imagine you can run a common block and change the internals to create the compression ratio and longevity you desire, cheaper than different blocks (casting different blocks sounds expensive).
One of my work colleagues, his other gig is engine design and build and we were discussing a 2l inline 4 turbo they make, it’s about 250bhp stock, one customer wanted 705bhp, now in his words, getting it upto 700bhp was quite easy, but getting it to stay together for 24hrs at speed was not.
One of my work colleagues, his other gig is engine design and build and we were discussing a 2l inline 4 turbo they make, it’s about 250bhp stock, one customer wanted 705bhp, now in his words, getting it upto 700bhp was quite easy, but getting it to stay together for 24hrs at speed was not.
It's always been a bit of a challenge doing that at the circuit in NW France.
Snufkin
pfm Member
From Wikipedia, the free encyclopedia:
225 kW version
Introduced in May 2019 this engine features a reinforced crankshaft with larger main bearings and new pistons with a lower 9.5:1 compression ratio, this allows the engine to take more boost pressure from a larger turbocharger, which blows compressed air through a reworked intake tract.
225 kW version
Introduced in May 2019 this engine features a reinforced crankshaft with larger main bearings and new pistons with a lower 9.5:1 compression ratio, this allows the engine to take more boost pressure from a larger turbocharger, which blows compressed air through a reworked intake tract.
LOL, what a coincidence. I am pleased I accurately conveyed your message over to this forum, I would have felt embarrassed if you had taken me to task over inaccuracies
I'd like to take up your offer of asking a question. Do you think it is possible to build a standard mass production petrol engine that meets latest Euro emissions limits and if serviced correctly can run reliably without major overhaul to say 300,000km?
Tony Lockhart
Avoiding Stress, at Every Opportunity
Surely that’s easy?
Yes, various sensors will need to be replaced, maybe the GPF could cause issues, and the turbocharger might give up, but a major overhaul in under 200,000 miles? Naaa, it’ll be fine, as long as bad luck or regular thrashing from cold don’t feature.
Yes, I had one. A 1992 2L 8v petrol Vauxhall Opel that ran in my hands to 155k miles, then in the less than sympathetic hands of my friend who took it beyond 200k miles/300k km. When it eventually died, the car having fallen apart around the engine, the engine ran like a Swiss watch, no knocks, rattles, no oil burning, nothing. Now OK, that engine didn't meet the latest EU standards, but there is no reason why it couldn't take on the latest sensors, ECU, etc to do so. The fundamental engine design hasn't changed that much AFAIA aware, the emissions are all about control of injection, ignition, etc and not the fundamental design. The Cav, by the way, got to 200k miles and I know for a fact that the cam cover was never taken off. So no "major overhaul", no overhaul at all, just 9k mile oil and filter changes, spark plugs and cam belts. No, I didn't believe it either.