Datatek said:

That statement is absolutely not true. Through improved control of the fuel/air mixture achieved by electronic fuel injection, modern engines are producing phenominal power output per litre compared to engine of the 60's and 70's and actually useing less fuel. Diesel engines are someway behind their petrol cousins in the development of the fuel injection systems whereas direct injection is a relatively new thing on petrol engines.
When I was playing with club level racing engines in the 70's, 100bhp per litre was the goal, the engines had narrow powerbands and were tempremental to say the least and 10 or 12mpg was not unusual These days 100bhp per litre engines can be seen in normal road going cars and motorbikes, they are not tempermental, have wide powerbands and use between a third and a quarter of the fuel to achieve the same power

Despite the losses introduced by catalytic "con" verters, improvements in combustion efficiency will continue to be made.

Click to expand...

wammers said:

Of course you miss the point entirely. I do not refer to engine developement, of course engines and fuel systems have evolved beyond anything thought posible a few years ago. We speak here of a particular engine, which is not modified in any way other than a power gain obtained by remapping the fuel system. It is not possible to obtain more power from that engine without injecting more fuel. Anyone who thinks that knows very little about engines.

Click to expand...

wammers said:

Of course you miss the point entirely. I do not refer to engine developement, of course engines and fuel systems have evolved beyond anything thought posible a few years ago. We speak here of a particular engine, which is not modified in any way other than a power gain obtained by remapping the fuel system. It is not possible to obtain more power from that engine without injecting more fuel. Anyone who thinks that knows very little about engines.

Click to expand...

Simon1975 said:

Not everyone would be proud to claim to know exactly how an engine works.

Most folks, like me, are only interested in the facts.

The facts are, I have more power and better fuel economy. That's it really.

Click to expand...

wammers said:

Glad you are happy. But to get back to my first statement. You can have more power OR better fuel economy. You cannot have both. If you use the extra power you use more fuel. Simples. If a 2.5 litre motor that produces 136 BHP, is boosted to 165 BHP by remapping the the fuel feed it has to use more fuel, if you use the 165 BHP. If you are only interested in facts please listen when someone tells you facts. This is not sales jargon but reality. Something for nothing and perpetual motion are nice thoughts but do not come into the realms of reality. Without changing anything else about the engine other than remapping the fuel supply, the only way to get more power is to inject more fuel. If you use that power you use more fuel. If you don't use that power, or maybe on motorway cruise you may get a little better economy because the spikes have been taken out of the factory setup. But if you use the power you use the fuel. Simple as that.

Click to expand...

Italian dave said:

Hi I hate to **** on your parade Simon but it is immpossible to get an increase in mpg and bhp unless youve significantly reduced the cod of your vehicle or made it alot lighter its a simple law of physics .
Maybe youre driving with a lighter foot now but I cant see how that would make much of a difference . Anyway who cares so long as your happy thats all that counts I suppose

Click to expand...

SpudH said:

Wammers and Italian Dave, both of you have missed the point of the difference between fuel consumption and fuel economy. Everything you've said is true of fuel consumption but not economy. Fuel consumption is fuel used per second and Fuel economy is distance covered per unit of fuel used.
Its not about how much fuel you use its how you use it.
The other important thing to note is to talk about torque instead of power. Peak power for these engines is up around 4,500rpm if I remember correctly. Peak torque is around 2100 and is fairly flat. In normal driving how often will you use full power? Pulling off at a T junction, passing out maybe but v.rarely in the whole. Peak torque - all the time. Its the increase in torque that has the positive effect on economy not power.

"Hi I hate to **** on your parade Simon but it is immpossible to get an increase in mpg and bhp unless youve significantly reduced the cod of your vehicle or made it alot lighter its a simple law of physics"

Completely untrue. Drive all the way home in first gear and see the difference in fuel economy. You've changed nothing in the car, your fuel consumption rate will be more or less the same but your fuel economy will drop dramatically. Why do think an "overdrive" was a big option to have in the 70's and 80's. Gearing has little to do with fuel consumption but a whole lot to do with fuel economy.

"You can have more power OR better fuel economy. You cannot have both. If you use the extra power you use more fuel. "
Again this is simply untrue in this context. As I said before if you cane it yes definitely you will use more fuel than pre-chipping, but we're talking here about normal driving.
An engine will burn, for arguments sake, 50% more fuel at 3000rpm than 2000rpm. Now say chipping uses 10% more fuel across the board. If your car produces ,through chipping, enough torque at 2000rpm that it can pull a higher gear for the same road speed it will run at lower revs for that given speed so its burning 10% more than pre-chip at 2000rpm instead of 50% more at 3000rpm. This is the fundamental behind the economy improvement.
When talking about economy you have to look at the drivetrain as a whole, not just the engine.

BTW I have no affiliation with any tuning company, I live in the S.West tip of Ireland far from anybody of that nature and I've actually flagged chipping several times as a possible source for blown headgaskets on the BMW engine. Its just that what you are both saying (with authority) is not the correct interpretation and is misleading for anyone thinking about fitting a chip.

Click to expand...

SpudH said:

If you read the post you will see that we are saying the same thing.

Yes extra fuel is injected per stroke but due to the extra torque generated a higher gear can be used and less strokes are required to travel from A to B.
No. of strokes multiplied by fuel quantity per stroke equals fuel consumed from A to B, due to a chipped engine having more torque it will change up earlier, pull higher gears, hold these higher gears longer hence increased mpg through less strokes used per journey (even though each individual stroke has used more fuel compared to un-chipped). As said before this is even more noticeable with an auto where it doesn't kickdown on hills and accelerates using lower revs.
Simples

If you're not convinced try removing your chip for a while to see the difference.

BTW I am perfectly happy discussing the various torque curves and merits of oversquare, long-stroke, straight, V, W, Boxer, 180/270/360 crank configurations should you wish.

Click to expand...

wammers said:

Truly is a cleaver device this PSI chip it also controls the oil pressure in the gearbox apparently. Stops box from changing down so you can use your extra torque. You cannot be serious? Simples.

Click to expand...