Boost Pressure On The 1.0 Eco Boost

[Eatonm112]

I treated myself to one of these a week ago -

http://www.amazon.co.uk/LYL-Bluetooth-Interface-Scanner-Diagnostic/dp/B00DY3EZSI/ref=pd_cp_23_1?ie=UTF8&refRID=17QF3X4CXR66NCCDP8VQ

I have been using it with the Torque App to monitor various sensors on my engine and yesterday I noticed that the boost pressure goes up to 22.5 PSI. My car has been re mapped by Superchips which is why I think its so high.

Has anyone done more testing of this sort too see what pressures different mappers use?

[Riordian]

Well...don't think.. that's the reason you measured these figures... 22.5 PSI is 1.55 bar. It's a lot.. have you noticed how long you keep this boost pressure? Mine has 1.5 bar with the remap, it's a black edition.

[SNC]

What bar do they run up to as standard? normal and overboost?

[Eatonm112]

Well...don't think.. that's the reason you measured these figures... 22.5 PSI is 1.55 bar. It's a lot.. have you noticed how long you keep this boost pressure? Mine has 1.5 bar with the remap, it's a black edition.

I have done some more data logging in my 125Bhp car that has been re mapped and when I accelerate with the pedal to the floor the boost pressure will go to 22.5 PSI at around 2000 Rpm and hold until I take my foot off the accelerator it will do the same in 1st to 5th gear.

Today, I drove my partners car which is a 100Bhp version and hasn't been re mapped and in 5th gear I put the pedal to the floor and the max recorded boost was around 15 PSI. The strange thing is when that you pull away in first gear with the pedal to the floor the boost will go to 10 PSI but then drop's off once the engine revs past 4000 rpm to around 7 PSI it also does a similar thing in second gear.

I was very surprised that the ECU is modulating the boost pressure on the 100 Bhp engine and I am now wanting to put my 125 Bhp engine back to standard to see if it does a similar thing I suspect that it does which is why the re map makes such a big difference in the low mid and high RPM range.

It would be great if someone with the Mountune 165 conversion could do a log as I would love to know how much peak boost that re map would have to be making to make the extra 15 Hp over the Super chips re map.

[SNC]

I have the same 125 as you, might get one of these OBD devices. I can switch my tuning box off and have a look at the cars standard boost when flooring it in all gears then have a look at it with the box on if that helps? but 1.55 bar seems rather high if the standard is the same as the 100 versions 1.03 bar, that's like almost a 50% increase.

[Willy]

I'll have a look and report back (MR165 owner)

[Willy]

[SNC]

So Willy, it looks like your hitting 19psi (1.31bar) which seems about a decent and not extreme increase (30%).

I don't know if I'd be comfortable with 1.55bar with the standard fitted turbo, what does the ST turbo run at?

[Willy]

19 psi you mean ;)

[Willy]

[SNC]

haha I got them the wrong way around duh, edited it to make more sense :P

[Riordian]

Thanks for going into trouble logging the car. Don't want to sound rude, but when you log your car you should not floor it from 2nd to 4th... the max boost pressure it not at 4.500-5000rpm which is when you shift gears. In 2nd gear and 1st, you have torque restrictors so you can't see what your actual boost pressure is. If you want and have the time, you can find an open road, put 3rd gear and start accelerating from 1.500-2000 rpm. That's how we are going to make absolutely correct figures :)

[Willy]

I did that also Riordian and boost reads the same at arround 19psi and no higher.

I would advise not flooring the car at such low revs because all that torque will damage the clutch in the long term.

I've noticed the boost pressure is limited in 1st gear only to arround 12psi ish were as boost pressure in the other gears is the same at 19psi ish.

[David73]

The non-turbo version sold in other countries has a maximum torque of 105Nm, ie from a manifold pressure of 1.0 bar.

The 100hp engine has a maximum torque of 170Nm. So the manifold pressure needs to be at least 1.6 bar.

The 125hp engine has a maximum torque of 200Nm. So the manifold pressure needs to be at least 1.9 bar.

The 140hp engine has a maximum torque of 210Nm. So the manifold pressure needs to be at least 2.0 bar.

Note this is absolute pressure. Sometimes pressure readings are taken as pressure above atmospheric so 2.0 bar could be indicated as 15psi.

[David73]

I would advise not flooring the car at such low revs because all that torque will damage the clutch in the long term.

I've noticed the boost pressure is limited in 1st gear only to arround 12psi ish were as boost pressure in the other gears is the same at 19psi ish.

The torque load of a certain value has the same effect on components irrespective of engine speed.

1st gear is limited by wheelspin. For instance a fwd car can't typically accelerate at more than 0.7g on a dry road.

On a car of about 1200kg 0.7g needs a tractive force of 8000N. Tyre radius of 0.25m gives driveshaft torque of 2000Nm. 1st gear 13x, gives 150Nm back at at the engine. No matter what the engine is capable of producing that is the maximum it can develop so there is no point giving full boost.

[Willy]

I was always lead to believe that using all that torque from a standstill was bad but with the car moving good / less strain on the clutch components?

[David73]

The point is that the torque is inherently self limiting. Try and exceed it and the wheels spin and revs rise. My example was a dry road; on a wet road the limiting value could approach half that (so traction control turns things down even further).

The way an engine works now is that your accelerator pedal is connected to a potentiometer that goes to the ECU. Consider the ECU as a barrier that competely isolates you and the metal from each other; it looks at the potentiometer and makes various deliberations depending on what it finds from other sensors and sets the air, fuel, ignition etc to try and meet your request. It won't always deliver what you want. The combination of air, fuel and engine speed gives mathematically known values of power and torque.

So a manufacturer builds a set of hardware with known mechanical capability. The manufacturer also writes the ECU software that enables the engine to work and produce those known values of power and torque. They're going to set ability to produce below the capacity to handle, surely? So if you're driving along at 1500rpm and press the pedal what you get is entirely down to the result of decisions embedded in the software; decisions that have been made back in a lab in Germany, wherever. OK, you might get audible or tangible vibration which you prefer to avoid but your human sensitivities are different to bits of metal.

[Willy]

So to put that in simple terms. Asking the car for full boost at 2000rpm will apply the same strain on the clutch as asking for full boost at 3000rpm ?

[iantt]

I would be more concerned with full boost at 2000 on the conrods than on clutch. A proper map should avoid full boost until 3000. Thats what I was told and practiced on self tuning my last car, suppose all depends on any inherent weaknesses on a particular engine.

[Eatonm112]

Mine makes full boost from 2000rpm and boosts to 22.5PSI after a superchips re map and now I am wondering how safe that level of tune is so I think I will look to change my map in the near future.

Its interesting that the MR165 boosts to 19PSI part of me thinks that the lower figure could be down to the more efficient inter cooler and better mapping of the engine control unit since the tuner has a close relationship with Ford thus understanding the ECU and engine in much better detail than an outside tuning company.

In time I think I will add the Mountune pipe work and intercooler as it will give my engine a better chance of lasting.

Also, I get a tiny bit of wheel spin on a dry day when giving it the beans in a straight line from standstill.

Going solely of boost figures isn't an exact science even if you are comparing the same engine due to being able to map in more or less valve over lap as that has a effect on the boost figures you will see measured from the intake manifold.

Someone mentioned that the ECU limited the boost in 1st gear to limit the torque produced by the engine and my thoughts were I hope that this isn't because the gearbox has syncros made of cheese.

[NQbbe]

This is quite interesting, considering I've heard of at least 3 people with Bluefin who had their 1st and 2nd gear syncro break down.

I'd expect the limitation from Ford is there to avoid exactly that problem - the torque churned out by the gearbox is after all higher in lower gears.

On a side note the ST also limits the boost in 1st and 2nd.

Furthermore my stock Black Edition (got both a ZS and a Black Ed.) feels quicker in 3rd than in 2nd, I suppose this is also down to limited boost in 2nd gear.

[iantt]

boost limiting in lower gears puzzles me, how is it limited? if by pcm control, how does it know what gear its in?

[ElliottWoodruff]

Hmmmm ran mine (100ps titanium) and it hits 13psi on regular driving....

Quite alot for a tiny little turbo!

[David73]

boost limiting in lower gears puzzles me, how is it limited? if by pcm control, how does it know what gear its in?

Depends on whether boost is being measured before or after the throttle. Don't forget the throttle is controlled by the ECU and not connected to your foot so when the ECU ignores you and closes throttle there is a pressure drop.

How does it know? When the wheels spin, it knows.

[David73]

So to put that in simple terms. Asking the car for full boost at 2000rpm will apply the same strain on the clutch as asking for full boost at 3000rpm ?

Technically, stress is the correct term. You are correct otherwise. People that put about scare stories do not understand what torque is.