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Speculating beyond bolt-ons.

16K views 46 replies 14 participants last post by  stuntdoogie 
#1 ·
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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#2 ·
i think something like a bolt on gtx2867 would be nice on that engine .. it seems that the car runs out of injectors around 250bhp but the focus injectors (and upgraded injectors) might be compatible..
having a bigger turbo means more efficiency but also colder intake charge temps which means that we could possibly run on the stock intercooler without any issues as long as the airflow is decent ..
i'm wondering if ATP turbo will make something for FiST owners
 
#7 ·
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.
 
#8 ·
well i wouldn't mind a turbo spooling a tad later .. it's pretty cool to have instant torque but when driving slowly in town honestly i'd prefer staying off boost and get better fuel economy... when i has my gencoupe i saw big inprovements in fuel economy when upgrading for a bigger turbo just because i was able to keep it off boost in the city
 
#9 ·
Good news!!

info@atpturbo.com
5:24 PM (20 hours ago)



to me

Hi David,

Thanks for contacting us.

For sure, we are working on turbo upgrade options for the Fiesta ST. We've been in development mode on this platform for a few months now so turbo upgrade options will not be a problem.

We just released 4 new turbo upgrades for the Focus ST with at least another half dozen coming in a few weeks.

The Fiesta ST platform will get similar treatment from us.

Thanks for bringing the demand for this application to light for us.

We appreciate it.
 
#11 ·
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.
 
#12 ·
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".
 
#14 ·
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.
 
#19 ·
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.
 
#21 ·
Why is your main goal tire spin? If you're spinning tires in higher gears you have way more power than you need and that's just going to create a tedious auto-x experience. I'd rather be able to point the car, mat the throttle and go rather than fussing around with modulating throttle to keep the car from pushing everywhere.

I think you need to pick your focus. Setting up this car as BOTH an auto-x and drag car with lofty expectations for both is going to be frustrating.
 
#22 ·
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.
 
#26 · (Edited)
Just remember if you do most of the mods you wrote about, this will be a totally different car. I think the popularity of the Fiesta ST is the balance. That balance goes away quickly once you're introducing big mods/power. I think 50-75 hp increase at most would be great with bolt ons. After that (or even before), you need to upgrade the brakes, suspension, clutch and deal with the massive torque steer that's bound to come. Which will suck btw. Also, this is a 1.6cyl. It's never going to have V8 torque down low.

Absolutely good luck with your project and I'd love to hear the numbers you end up with. I assume most Focus ST parts will be an upgrade for this car. Tons of info out there now about the route those guys have gone. Be careful what you wish for though........a massively modded Fiesta ST may not be as fun as you think. On the street or at the track. 1/4 mile probably if you can make it hook and not bog with slicks.
 
#30 ·
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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