[Mk2] [Turbo] i want 300bhp ish :P

[dylan5084]

Ok, so is it possible to just run an external map sensor, upgrade to the rev 3 or piggy back ecu ditch the afm and screw up the boost?

Have already got steel head gasket, and a stage 3 hybrid fensport turbo

[gazrev1tubby]

What you need to bear in mind, is that a hybrid turbo will push more cfm than a stock one will, so in essence, if you run higher boost, you need to ensure that your fuelling can cope with the volume of air being delivered.

I know some folk will disagree, but it's generally known that rev 1/2 injectors are safe for 1.1 bar of boost, and rev 3+ injectors will support 1.3 bar - on stock turbo units. Also, at these levels, you're outside of the stock ecus maps, so would need a piggy back or standalone to to correct the fuel maps.

On stock management, rev 1/2 1 bar, and rev3+ 1.2 bar is generally considered safe. Now the difference that 0.2 bar makes in the the real world, is probably circa 25 bhp.

Having spent hours and hours, and a lot of money over the years on mine, playing with standalones and also doing a rev3 conversion on mine, my advice would be that it's a lot of money to spend - for a relatively small gain.

Just my 2p, but if you were building a monster high power weapon, then changing management would obviously be necessary. For an everyday road car on a limited budget, I wouldn't bother

[bobhatton]

What you need to bear in mind, is that a hybrid turbo will push more cfm than a stock one will, so in essence, if you run higher boost, you need to ensure that your fuelling can cope with the volume of air being delivered.

I know some folk will disagree, but it's generally known that rev 1/2 injectors are safe for 1.1 bar of boost, and rev 3+ injectors will support 1.3 bar - on stock turbo units. Also, at these levels, you're outside of the stock ecus maps, so would need a piggy back or standalone to to correct the fuel maps.

On stock management, rev 1/2 1 bar, and rev3+ 1.2 bar is generally considered safe. Now the difference that 0.2 bar makes in the the real world, is probably circa 25 bhp.

Having spent hours and hours, and a lot of money over the years on mine, playing with standalones and also doing a rev3 conversion on mine, my advice would be that it's a lot of money to spend - for a relatively small gain.

Just my 2p, but if you were building a monster high power weapon, then changing management would obviously be necessary. For an everyday road car on a limited budget, I wouldn't bother

On high octane fuel I have been for the last two years running 1.5 bar boost on a stock Rev 2 engine and ECU with a CT20B giving 300 HP at the flywheel.

My son is running a T3/4 turbo and 274 deg cams with a stock Rev 3 ECU at 350 HP.
No need to add or change the ECU untill you need bigger injectors.

The thing that keep the engines together is the high octane fuel

[gazrev1tubby]

Exactly right bob, but when you say high octane, are you referring to anything higher than 99ron, which is the highest available from the pumps?

[bobhatton]

Exactly right bob, but when you say high octane, are you referring to anything higher than 99ron, which is the highest available from the pumps?

Yes, 110 octane

[dylan5084]

How much you payin per litre of 110, I take it its not readily available?

[bobhatton]

How much you payin per litre of 110, I take it its not readily available?

We buy 200L drum of C16 and mix it with 99 road fuel, I think it is around £650 a drum

[Al-sw20]

I pay $3 a litre for 110 LL off the pump. Thats £1.50 a litre btw.

[dylan5084]

I pay $3 a litre for 110 LL off the pump. Thats £1.50 a litre btw.

Lucky you, diesel is almost £1.50 a litre at the pumps here, and was over £1.50 a year ago! Ridiculous the tax we pay on fuel.

[Turbonoz]

What you need to bear in mind, is that a hybrid turbo will push more cfm than a stock one will, so in essence, if you run higher boost, you need to ensure that your fuelling can cope with the volume of air being delivered.

I know some folk will disagree, but it's generally known that rev 1/2 injectors are safe for 1.1 bar of boost, and rev 3+ injectors will support 1.3 bar - on stock turbo units. Also, at these levels, you're outside of the stock ecus maps, so would need a piggy back or standalone to to correct the fuel maps.

On stock management, rev 1/2 1 bar, and rev3+ 1.2 bar is generally considered safe. Now the difference that 0.2 bar makes in the the real world, is probably circa 25 bhp.

Having spent hours and hours, and a lot of money over the years on mine, playing with standalones and also doing a rev3 conversion on mine, my advice would be that it's a lot of money to spend - for a relatively small gain.

Just my 2p, but if you were building a monster high power weapon, then changing management would obviously be necessary. For an everyday road car on a limited budget, I wouldn't bother

On high octane fuel I have been for the last two years running 1.5 bar boost on a stock Rev 2 engine and ECU with a CT20B giving 300 HP at the flywheel.

My son is running a T3/4 turbo and 274 deg cams with a stock Rev 3 ECU at 350 HP.
No need to add or change the ECU untill you need bigger injectors.

The thing that keep the engines together is the high octane fuel

The thing that keeps the engines together is lack of knock

Instead of running high octane fuel, you can go the route of aftermarket ECU, and control the timing. Knock control is achievable via high octane fuel and fixed OEM timing stipulated by the last column on the timing map, or lower octane fuel and user-defined timing on an extended timing map. The end result is the same.

[Super_red]

What you need to bear in mind, is that a hybrid turbo will push more cfm than a stock one will, so in essence, if you run higher boost, you need to ensure that your fuelling can cope with the volume of air being delivered.

I know some folk will disagree, but it's generally known that rev 1/2 injectors are safe for 1.1 bar of boost, and rev 3+ injectors will support 1.3 bar - on stock turbo units. Also, at these levels, you're outside of the stock ecus maps, so would need a piggy back or standalone to to correct the fuel maps.

On stock management, rev 1/2 1 bar, and rev3+ 1.2 bar is generally considered safe. Now the difference that 0.2 bar makes in the the real world, is probably circa 25 bhp.

Having spent hours and hours, and a lot of money over the years on mine, playing with standalones and also doing a rev3 conversion on mine, my advice would be that it's a lot of money to spend - for a relatively small gain.

Just my 2p, but if you were building a monster high power weapon, then changing management would obviously be necessary. For an everyday road car on a limited budget, I wouldn't bother

On high octane fuel I have been for the last two years running 1.5 bar boost on a stock Rev 2 engine and ECU with a CT20B giving 300 HP at the flywheel.

My son is running a T3/4 turbo and 274 deg cams with a stock Rev 3 ECU at 350 HP.
No need to add or change the ECU untill you need bigger injectors.

The thing that keep the engines together is the high octane fuel

The thing that keeps the engines together is lack of knock

Instead of running high octane fuel, you can go the route of aftermarket ECU, and control the timing. Knock control is achievable via high octane fuel and fixed OEM timing stipulated by the last column on the timing map, or lower octane fuel and user-defined timing on an extended timing map. The end result is the same.

Is pre ignition not caused by the compression in the cylinder? I was under the impression that if the fuel ignites under compression this would cause knock and the only ways to reduce this are to lower static CR or increase the fuels resistance to combust. I cant see how ignition timing can stop pre ignition?

[rs007]

Is pre ignition not caused by the compression in the cylinder? I was under the impression that if the fuel ignites under compression this would cause knock and the only ways to reduce this are to lower static CR or increase the fuels resistance to combust. I cant see how ignition timing can stop pre ignition?

Yes, thats pre-ignition. Mapping can affect it because ignition timing too advanced, or fuel maps too lean, can raise combustion chamber and cylinder temps. Hotter cylinder/combustion temp coupled and the higher the CR increases the chance of the mixture igniting before the spark at some point in the run. High IATs don't help either, they never help anything.

Detonation is another thing, and is an uncontrolled chaotic burn of the mixture post spark

Both are bad, but from what I've seen and gut feeling, its detonation that destroys most of the engines we hear about, and fuel mapping has a massive affect on the chances of det occuring (or not).

[Super_red]

I thought that the blast front from the pre ignition hitting the blast front from the spark was what caused knock? And the resulting hot spot is what damages pistons?

[rs007]

I thought that the blast front from the pre ignition hitting the blast front from the spark was what caused knock? And the resulting hot spot is what damages pistons?

That will be one thing that will follow on from pre ignition, because inevitably, a spark will fire milliseconds later causing a second flame front.

To visualise detonation, its better to think of explosives IMO, where largely speaking the terminology is interchangeable, but easier to demonstrate.

Low explosives burn - fast - but they still burn. These are used in bullet cartridges. They burn in a predictable measurable manner, pushing the bullet progressively and efficiently down the barrel, this is a burn, and isn't too dissimilar to ideal fuel/air mixture burn in an engine, the piston being the bullet in the analogy.

High explosives detonate. Its a much faster almost instantaneous degradation of the base material, releasing a far more vicious and unpredictable force. If you packed a shell casing in a pistol with C4 for example, and detonated it, it would blow the cartridge chamber to pieces. Its too intense - the forces generated are so extreme that the mechanism surrounding the reaction cannot contain them. Thats kinda what detonation is in a petrol engine, though not quite as extreme

I'm only being particular because it all gets labeled as "knock" although the two conditions - pre-ignition and detonation are very different in terms of what is going on. They sound very different too, although fortunately for me I haven't had the displeasure of hearing much of either lol!

I might have when I start pushing the boundaries of my 3S-GTE right enough hahaha!

[Super_red]

Is the difference between an explosion and a fast burn not the sonic boom? Is this not what causes the sound when knock occurs? Is pre ignition not dangerous then? I was always led to beleive this is what holed pistons since the hot spot was predictable and always in the same place melting a hole in the piston.

[Turbonoz]

Pre-ignition is the most destructive & dangerous combustive event to occur in an engine.

Pre-ignition: The mixture is ignited prior to the timed spark event. Causes are simply hot spots within the combustion chamber. Typically caused by thin-wire precious metal plugs (plat. & iridium) designed to run hot in order to burn off all deposits which do not dissipate heat anywhere near as well as copper plugs. This is why I only run copper plugs in any engine I'm working with. Platinum plugs are for 60k service intervals in new engines running factory power. Carbon deposits themselves can ignite the mixture as well.

Pre-ignition is caused by physical 'issues' within the combustion chamber and is silent. The resultant damage (melted piston) is due the huge amount of heat & pressure from attempting to compress an explosion, rather than the explosion forcing the piston downwards to be converted into mechanical work.

Detonation: The spontaneous cumbustion of the remaining mixture after the timed spark event has initiated the burn process. The crackling noise you hear is due to the mechanical reaction of the surrounding materials to the severe, instantaneous increase in pressure when the two opposing flame fronts meet. Think of hitting a tuning fork and the resultant frequency-related sound, in a combustion chamber it occurs at ~6.4kHz. Knock sensors are simply piezo-electric sensors comprised of crystals designed to output a voltage when subjected to a shock of the correct frequency (typically 5.3-6.4khz range).

Detonation is caused by high temperatures & pressures, too low an octane (resistance to ignition), incorrect timing (too advanced) or not enough fuel. It is characterised by what is referred to as "pinging", "pinking", "knock", "det" etc. I would describe the sound like an empty crisp packet being scrumpled up by hand for a turbocharged vehicle on boost, and more like a pan of marbles in an NA vehicle (quite often caused by a faulty cam/crank sensor). The resultant mechanical damage is due to the sharp pressure increases which "shock" the piston, characterised by cracked ringlands, and pitting on the cylinder head and around the top of the cylinder bores.

'Knock hysteresis' is also worth mentioning here. Due to the 'snowball' effect of detonation causing more heat which in turn promotes detonation more readily, it takes a more retarded timing value & richer mixture (cooling effect) to halt detonation than it does to prevent it in the first place.

[rs007]

Pre-ignition is the most destructive & dangerous combustive event to occur in an engine.

Pre-ignition: The mixture is ignited prior to the timed spark event. Causes are simply hot spots within the combustion chamber. Typically caused by thin-wire precious metal plugs (plat. & iridium) designed to run hot in order to burn off all deposits which do not dissipate heat anywhere near as well as copper plugs. This is why I only run copper plugs in any engine I'm working with. Platinum plugs are for 60k service intervals in new engines running factory power. Carbon deposits themselves can ignite the mixture as well.

Pre-ignition is caused by physical 'issues' within the combustion chamber and is silent. The resultant damage (melted piston) is due the huge amount of heat & pressure from attempting to compress an explosion, rather than the explosion forcing the piston downwards to be converted into mechanical work.

Detonation: The spontaneous cumbustion of the remaining mixture after the timed spark event has initiated the burn process. The crackling noise you hear is due to the mechanical reaction of the surrounding materials to the severe, instantaneous increase in pressure when the two opposing flame fronts meet. Think of hitting a tuning fork and the resultant frequency-related sound, in a combustion chamber it occurs at ~6.4kHz. Knock sensors are simply piezo-electric sensors comprised of crystals designed to output a voltage when subjected to a shock of the correct frequency (typically 5.3-6.4khz range).

Detonation is caused by high temperatures & pressures, too low an octane (resistance to ignition), incorrect timing (too advanced) or not enough fuel. It is characterised by what is referred to as "pinging", "pinking", "knock", "det" etc. I would describe the sound like an empty crisp packet being scrumpled up by hand for a turbocharged vehicle on boost, and more like a pan of marbles in an NA vehicle (quite often caused by a faulty cam/crank sensor). The resultant mechanical damage is due to the sharp pressure increases which "shock" the piston, characterised by cracked ringlands, and pitting on the cylinder head and around the top of the cylinder bores.

'Knock hysteresis' is also worth mentioning here. Due to the 'snowball' effect of detonation causing more heat which in turn promotes detonation more readily, it takes a more retarded timing value & richer mixture (cooling effect) to halt detonation than it does to prevent it in the first place.

Good post

To Dylan - you should get yourself a copy of Jeff Hartmans "how to tun and modify engine management systems"

Change from £20 delivered from Amazon and the like, and its even better than I thought - open minded no limits thinking, and case studies (in multiple vehicles) to prove the theory out in many different practical settings.

Whole section devoted to rev2 MR2 turbo

Very educational read, and IMO worthwhile purchase for any avid tinkerer

[dylan5084]

Pre-ignition is the most destructive & dangerous combustive event to occur in an engine.

Pre-ignition: The mixture is ignited prior to the timed spark event. Causes are simply hot spots within the combustion chamber. Typically caused by thin-wire precious metal plugs (plat. & iridium) designed to run hot in order to burn off all deposits which do not dissipate heat anywhere near as well as copper plugs. This is why I only run copper plugs in any engine I'm working with. Platinum plugs are for 60k service intervals in new engines running factory power. Carbon deposits themselves can ignite the mixture as well.

Pre-ignition is caused by physical 'issues' within the combustion chamber and is silent. The resultant damage (melted piston) is due the huge amount of heat & pressure from attempting to compress an explosion, rather than the explosion forcing the piston downwards to be converted into mechanical work.

Detonation: The spontaneous cumbustion of the remaining mixture after the timed spark event has initiated the burn process. The crackling noise you hear is due to the mechanical reaction of the surrounding materials to the severe, instantaneous increase in pressure when the two opposing flame fronts meet. Think of hitting a tuning fork and the resultant frequency-related sound, in a combustion chamber it occurs at ~6.4kHz. Knock sensors are simply piezo-electric sensors comprised of crystals designed to output a voltage when subjected to a shock of the correct frequency (typically 5.3-6.4khz range).

Detonation is caused by high temperatures & pressures, too low ane (resistance to ignition), incorrect timing (too advanced) or not enough fuel. It is characterised by what is referred to as "pinging", "pinking", "knock", "det" etc. I would describe the sound like an empty crisp packet being scrumpled up by hand for a turbocharged vehicle on boost, and more like a pan of marbles in an NA vehicle (quite often caused by a faulty cam/crank sensor). The resultant mechanical damage is due to the sharp pressure increases which "shock" the piston, characterised by cracked ringlands, and pitting on the cylinder head and around the top of the cylinder bores.

'Knock hysteresis' is also worth mentioning here. Due to the 'snowball' effect of detonation causing more heat which in turn promotes detonation more readily, it takes a more retarded timing value & richer mixture (cooling effect) to halt detonation than it does to prevent it in the first place.

Good post

To Dylan - you should get yourself a copy of Jeff Hartmans "how to tun and modify engine management systems"

Change from £20 delivered from Amazon and the like, and its even better than I thought - open minded no limits thinking, and case studies (in multiple vehicles) to prove the theory out in many different practical settings.

Whole section devoted to rev2 MR2 turbo

Very educational read, and IMO worthwhile purchase for any avid tinkerer

Now that sounds like something I might read!

[bobhatton]

What you need to bear in mind, is that a hybrid turbo will push more cfm than a stock one will, so in essence, if you run higher boost, you need to ensure that your fuelling can cope with the volume of air being delivered.

I know some folk will disagree, but it's generally known that rev 1/2 injectors are safe for 1.1 bar of boost, and rev 3+ injectors will support 1.3 bar - on stock turbo units. Also, at these levels, you're outside of the stock ecus maps, so would need a piggy back or standalone to to correct the fuel maps.

On stock management, rev 1/2 1 bar, and rev3+ 1.2 bar is generally considered safe. Now the difference that 0.2 bar makes in the the real world, is probably circa 25 bhp.

Having spent hours and hours, and a lot of money over the years on mine, playing with standalones and also doing a rev3 conversion on mine, my advice would be that it's a lot of money to spend - for a relatively small gain.

Just my 2p, but if you were building a monster high power weapon, then changing management would obviously be necessary. For an everyday road car on a limited budget, I wouldn't bother

On high octane fuel I have been for the last two years running 1.5 bar boost on a stock Rev 2 engine and ECU with a CT20B giving 300 HP at the flywheel.

My son is running a T3/4 turbo and 274 deg cams with a stock Rev 3 ECU at 350 HP.
No need to add or change the ECU untill you need bigger injectors.

The thing that keep the engines together is the high octane fuel

The thing that keeps the engines together is lack of knock

Instead of running high octane fuel, you can go the route of aftermarket ECU, and control the timing. Knock control is achievable via high octane fuel and fixed OEM timing stipulated by the last column on the timing map, or lower octane fuel and user-defined timing on an extended timing map. The end result is the same.

Sorry you are wrong there. You cannot replace high octane fuel just by retarding the timing. You can make the engine run that way but that is how the blocks get cracked and a lot of power is lost.
The timing comes about by the engine design, mostly by the head design; it is fixed give or take a degree or two.

Today’s turners find it too easy to just back off the timing, when it is the wrong thing to do. If an engine starts to knock, there is something wrong with the design or the build, that has to be put right, not change the timing too much.

[Turbonoz]

I'm working with the stock engine, hence the design is a constant, not a variable. I chose not to use race fuel for the sake of showing what can be achieved on pump fuel, as it is attainable by everybody. Ergo, octane is a constant, not a variable.

What I have written is 100% correct, I'm afraid. Not wanting to be undiplomatic, but you are wrong. It's all about the minimum timing for best torque. You find this by mapping, the actual timing value is not important, the resultant torque is, determined by individual cell mapping on an eddy-brake dyno.

If you have race fuel, you map to that. If you have 99RON, you map to that. If you have high IATs, you map to that. If you have a 20k engine, you map to that. And so on.

Not everyone has tens of thousands of pounds to build an engine and feed it with race fuel. You need to think of pump fuel & standard engine design being the baseline, your perspective is that everyone has a race-spec engine and race fuel. By having stock engine & pump fuel, it's not losing power. You're able to gain power by spending thousands on engine design & race fuel....

If an engine knocks, you simply reduce timing in the first instance. There is of course many other methods including cooling the intake charge temps, running a colder grade plug, running a higher octane fuel, building a race-spec engine.

Basically, you map to the components you are given. I will make more power mapping your specced engine & race fuel with my T78 than I will my stock engine on pump fuel with my T78