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Bolt-ons are great. I'm sure a down pipe, FMIC upgrade, cold air kit and a tune will make a good improvement but some people will want more.

This thread is about the limitations of the stock 1.6 Ecoboost and how they can be addressed. Its speculation because no one has been pushing the limits and talking about it yet.

#1, no tuning software. We can't tell what is going on with the ECU maps so we can't see where Ford tuned around the hardware.

COBB has the Accessport and soon will have Accesstune Race which should solve the tuning issue.

#2, a really small turbo. Looking at dyno curves and the description of the COBB 93 octane tune (20.5 psi boost at torque peak tapering off to 13.5 psi at red line), it looks like the compressor is too small to push a lot of boost at high rpm.

A bigger turbo seems to be the answer but going too big will mean sacrificing that almost off idle surge of torque. A first place to look is the Borg Warner K03 that is used in the Focus ST and capable of 300 HP. Looking beyond that, Borg Warner's EFR series has a really impressive set of features like a low inertia Titanium Aluminide impeller, dual row ceramic ball bearings, a good integrated waste gate and very nice thin wall stainless turbine housing. The EFR 6258 is the smallest one available but good for 350+ whp on a Miata 1.8 with full boost achieved around 3,000 rpm. If we can find a turbo that can maintain the 20.5 psi boost and 220 ft-lbs of torque until 6,500+ rpm, 270 whp is possible which is a reasonable goal for the engine I think.

#3, the high pressure fuel pump. With a tiny turbo I don't think anyone is going to find the limit but looking at the Bosch web site, it seems like they only make one basic pump and the volume supported is determined by the fuel pump lobe on the cam.

The Ford Focus ST seemingly has the same pump and can support about 300 whp so if the Fiesta runs out of fuel, the fix might be as simple as a custom cam with an exact copy of the Focus ST fuel pump lobe.

#4, fuel injectors. Hopefully these do not limit anything because they are application specific.

#5, traditional turbo plumbing issues. Exhaust restrictions, cold side plumbing, etc. If you are going for a turbo upgrade, making nice plumbing seems like a no-brainer. Increasing the size of the throttle body and porting the intake manifold might be places to find power. Porting the cylinder head might be worthwhile too. It seems like there are going to be several FMICs to compare, hopefully one will be appropriate at the 300 whp level.

My guess is that the next level in performance is a custom exhaust manifold, EFR 6258 turbo, high flow down pipe, high flow exhaust, FMIC upgrade, good plumbing, possibly a custom cam and a tune.

The manifold, downpipe, and plumbing need custom fabrication and finding a custom cam might be hard but nothing is really out of reach. Since I can do a lot of the custom fabrication it seems like only a question of time and money ($1,450 turbo, probably $1,500 for stainless and intercooler, $625 for tuner, maybe 50 hours of fab).

If there are any additional issues to address, known good parts sources or other ideas, this is the thread for it.

 

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That's a nice picture, it shows the Bosch high pressure fuel pump and even the way it is driven by a lobe on the camshaft.

That and the turbo are probably the limiting factors, just look at that tiny turbo.

I did some research on aftermarket turbos and that is how I read about the BW EFR series. They have just about every go faster feature out there including ceramic ball bearings and a titanium-aluminide impeller which weighs about 1/2 as much as a comparable size Inconel impeller and that makes it spool quickly. It also has an integrated waste gate and boost control solenoid valve so that its an easy retrofit for OEM style turbochargers.

Lastly I was told by a guy who has lots of turbo Miata experience that the smallest EFR has power potential like a disco potato with spooling like the smallest common Garret aftermarket turbo.

Trying to make big power from a 1.6 without losing that quick spool and 2,000 rpm torque is not something that is done very often and the parts choices are usually a large compromise. You get a peaky motor with lag if you don't choose right. Starting with the best available makes sense when you look at the work and $$ involved in a full system upgrade.

I might have to call up Pumaspeed about getting just a header flange, but I'll have to read about welding 321 to 316 to be sure that it won't cause cracks. If that combo isn't a good one I'll just have to get a flange CNC cut from 321.

 

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I just finished watching all of the instructional videos and took my first stab at using the Borg Warner EFR matchbot.

I'm not sure everything is right and I would like to reverse engineer a match from a similar engine with good dyno data to see how close it gets and where I need a fudge factor.

Any way, 5.6 psi at 2,000 rpm, 17 psi at 3,000 and 21 psi from 4,000-7,000 rpm with 330 HP at the crank, that turbo should spool pretty good at low rpm and deliver plenty of air. If the direct injection can keep up that sounds just about perfect to me.

I'll eventually do some heat exchanger math to refine the inputs and I'll be emailing some people at Borg Warner to make sure I'm doing it right.

 

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I intend to do a brake upgrade, coilovers, a little aero and maybe a bolt in harness bar/roll bar.

I'm hoping the rotating assembly can take it. Usually a turbo engine is designed to handle a little detonation which is far worse than a 50% increase in power. I think the key is "don't detonate".

 

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Well that's kind of the point, I would love it if I had enough power to smoke the tires from a roll in first, I don't like how it bogs.

One questionable thing, the matchbot output says the wastegate is flow choked at 4,000+ rpm. I'm not exactly sure what that means but I hope it doesn't mean a secondary wastegate is required.

Obviously boost control is critical, without it, detonation would happen any time rpms went very much over 3,000 rpm.

One more thing to look in to: anti-lag systems.

Traditional race systems are always active, very loud, waste fuel and tear up the turbo. If you tone it down just trying to spool the turbo a bit instead of build full boost at idle and only use it in certain throttle positions in a special race map, the turbo might live. Luckily with direct injection we may be able add fuel directly to the exhaust while the exhaust valve is open. I think that could be much gentler than a bang-bang system. You need extra air too, either by a lean burn in the engine or the race systems plumb air with something like a blow off valve in to the exhaust.

I've found one thesis summary on a system like this, I'm trying to get a copy.

 

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It looks like I need to coordinate an inter-library loan with Austria.

I hope the paper is worth the effort.

 

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I'm not talking about a stock turbo and I would rather use less than full throttle than lack power.

In higher gears it requires an absurd amount of power to smoke the tires from a roll so soft tuning just makes for slow in gear acceleration tests.

If I wanted to go slow bolt-ons and a stock turbo would be just fine.

If I get serious torque steer problems I'll look for Focus RS Revo-knuckle struts but up to that point I will be careful to make the throttle response linear rather than softening full throttle.

My goal is a car that can hang with a stock Mustang 5.0 in a straight line, kick ass in an autocross, be fully street able and look more economy car than race car.

 

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My main goal is not tire spin, its not bogging when I hit the gas from a slow roll in first.

Enough power to spin the wheels is enough that it won't bog.

I don't recall the quote but I think either a Porsche 917 driver or a Can Am driver said I'll have enough power when I can spin the wheels all the way to the end of the straight on the longest track we race.

I'm not going for that but he was right about how much is enough. Its always better to have and not need than need and not have.

 

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There are really no parts from the Focus ST that translate to the Fiesta ST except maybe the limited slip diff might be compatible.

The Focus RS Revo-knuckles I mentioned would be essentially a complete redesign of the front suspension and possibly steering, an extreme solution if I wind up with a really bad torque steer problem.

I don't think it will be bad, something like a Cobb stage 3 Focus ST has lots more torque than I can hope for and I haven't heard people saying the torque steer is unbearable. The Fiesta ST is just a slightly smaller and lighter car, there is no reason to expect big problems from around 300 HP.

If I'm going to upgrade the turbo, the EFR I'm looking at is the option that should spool as quick as anything bigger than a KP39 and once you get to the point of a new turbo, new plumbing, ECU tuning devices and software, it does not make sense to leave power on the table if all you have to do is write a decent tune to get it. Its not a matter of building for 300 HP, its a matter of building for that turbo and 300+ HP is the potential if you build it right. If there was another turbo out there that would spool quicker and still give me more high rpm boost than stock, I would be trying to figure out its match but there isn't anything like that out there.

I'm going to try to do better than a decent tune because I know some people who can help me squeeze out more. A race tune with ALS might be possible so I'm going to see what can be done. I would probably use ALS with a two-step rev limiter and neither would be used often, just a tool for certain race situations when points are on the line.

What makes a turbo spool quickly:

#1, low inertia in the turbine and compressor wheel.

#2, low friction in the bearing system.

#3, a twin scroll housing to better scavenge the exhaust pulse energy at low rpm.

The turbo I'm looking at is the smallest EFR turbo and has a Titanium Aluminide turbine wheel which has about 1/2 the density of a Nickel super alloy wheel (like Inconel) so the inertia is low. The bearing assembly uses large ceramic ball bearings rather than plain bearings, this reduces friction and increases the maximum bearing thrust load which improves the durability. It also has a twin scroll housing so all the boxes are checked.

If you want more power than bolt-ons can provide, its going to be this path or very similar. Its a shame but the KP39 is just tiny so the normal bolt-on stuff will only give small power increases.

I'm not worried about changing the balance of the car and I'm not going for a drag race setup, if anything I'm going for a time attack/street setup.

 

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Exhaust manifold design thoughts:

Headers are usually designed to tune for exhaust scavenging at one specific rpm, longer and smaller tubes shift the tuning point to lower rpm but at some point small becomes a restriction at higher rpm.

In a Fiesta, small tubes are easy but long won't work. Throw in a turbo and a lot of the traditional rules go out the window.

First thing, a twin scroll turbine housing dictates a sort of 4-2-1 header (tri-Y). Cylinders 1,4 and 2,3 are paired with the tubes merging close to the turbo flange and the twin scroll housing itself kind of acts like the third "Y".

Its hard to find the speed of sound in exhaust gas at high pressure but it's got to be greater than low pressure which would suggest that longer pipes are needed to tune a turbo with significant back pressure but STs don't have a lot of space so if I can get close to 16" I'll be happy (I bet 32" would be closer to tuned).

There is a lot of discussion comparing equal length headers with cast manifolds and fabricated log style manifolds. Race cars seem to have nice equal length setups if they will fit but people who have tried both say the differences are small.

Burns Stainless has some things to say that make a lot of sense, they like equal length, smooth bends and slip joints to relieve stress. I think I can agree with all of that and will try to build that as much as possible.

When the topic comes to length, diameter and pulse tuning, things get fuzzy. A twin scroll turbine uses pulse energy to spool up quickly so that's a topic I'm interested in.

Two things that seem to work together are that pulse energy relies on the velocity of the gas and as a gas is allowed to expand it slows but the turbine back pressure at high rpm is probably greater than that of a slightly small primary tube so I want to match the size of the exhaust port and carry that almost all the way out to the turbo flange. I want the transition from exhaust port size to turbo flange size to be smooth so that my low volume header will maintain as much velocity and pulse energy as possible.

Even if the primary pipes are kept small there is no way to make them long enough to tune for mid-range but trying to go short does not seem to hold any advantage. Equal lengths would help but I will be satisfied if I can keep the paired primaries equal.

Of course the biggest priority is making it fit but now I have a good idea of how I want to make them.

 

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Yeah, I've read a lot of opinions about heat and there are header wraps and turbo blankets if I find heat loss is a problem.

At low rpm everything is going to be cool and trying to suck heat out of the exhaust gas but heat transfer happens over time so keeping the pulse fast and not allowing the gas to expand before the turbine will hopefully get the exhaust through the turbo before it has a chance to cool much.

I've seen that Pumaspeed header. I sent them an email asking to buy a header flange, haven't heard back.

The main problem is that it still uses a KP39 turbo.

What I have to build is going to have longer pipes because the paired tubes have to be on the sides rather than front and back of the turbo flange.

Here is a picture of what Burns Stainless thinks is a near ideal turbo header (for a sand rail):

It looks like a 4 in to 2 in to twin scroll turbo flange with pretty long primary tubes. I see there is a 2-1 merge before a section of straight tube that heads to the turbo flange, I'll have to ask about that straight section.

Any way, that header does not look like it was designed to retain heat. Mine will certainly be shorter with smaller diameter primaries, ideally something half way between the Pumaspeed and the Burns

 

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I've looked at a lot of full race stuff after seeing their Fusion and talking to their guy at SEMA.

That layout looks like its probably too big for a Fiesta, probably for a longitudinal engine Sylvia or something.

One thing you will notice is two wastegate tubes, one for each scroll. The EFR has an integrated wastegate so that's two wastegates you don't have to buy and a bunch of plumbing you can avoid. The price looks a lot better when you factor that in.

Full race has good stuff and probably will make what I want to build eventually but I'm not going to wait.

I should place an order with Burns soon but I'm not sure they make 321 bends small enough to match the exhaust port.

 

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I was thinking about the fuel system trying to find a company that does high performance injectors.

What I read that surprised me is that the 1.6 has the fuel injector right next to the spark plug, firing pretty much directly down in to the cylinder. I had thought it was on the side like the 2.0.

Looking further, I thought the injector was a Bosch but it seems like Continental might be the OEM, especially when their press releases indicate that their new MSI XL3 injector entered production in an un-named 4 cylinder 1.5 liter gasoline turbo direct injection engine earlier this year (sounds like the EcoBoost 1.5) and their older generation MSI XL2 injector is a 6 hole that sounds like what the 1.6 has.

From what I've read it seems like the 1.6 has many fathers, base engine design dates back to Yamaha, high pressure fuel pump and ECU(?) by Bosch, turbocharger and TiVCT(?) by Borg Warner and injectors by Continental.

Any way, the XL2 injector is designed to work at 150 bar while the Bosch high pressure fuel pumps can work at 200 bar or more.

If we are really lucky the XL3 injector will be physically and electrically compatible because its a 250 bar injector and would probably move the bottleneck to the pressure output of the HPFP which could be increased by a cam with more or taller lobes.

I want to look at what the 1.0 EcoBoost has, but this might explain how the 1.6 may have an injector size issue.

 

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I keep my cars for a long time, I don't need a new one every year, that's why I'm not afraid of spending time and money to make it better.

I think I've heard you say things about fuel pumps before. I think the high pressure fuel pump operates around 100-150 bar, that's up to about 2,100 psi, maybe more if the system isn't what I suspect. Its not an engine like the Scion FRS that has supplementary port fuel injection that runs 3-4 bar.

If Bosch made an electric fuel pump that could supply pressure like that, it would look like a lowrider hydraulic pump and you would probably have to mount it in the front passenger foot well because it wouldn't fit anywhere under the hood.

 

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What's the flow rate at 2,100 psi?