Duratec 2.0 HP increase

[sf4018]

I’m looking to increase the HP of my standard 420R Duratec 2.0 engine by 20-30 HP to be a little more competitive in a race. I have an unlocked ECU and a fuel system that pushes 60 psi of fuel. The tune is setup rich to better ensure engine life and fuel consumption is not a problem (the tank is ~14 gallons).

Does anyone have any suggestions or recommendations?

[KnifeySpoony]

Roller barrels? 

[JohnCh]

I am far from an expert but have been researching the Duratec for the past 20 years and during that time have spoken at length with a number of tuners and owners on both sides of the pond who have built and dyno'd these engines.  I've also had Duratecs in three different stages, each of which has been on the dyno.  The following is probably more than you want to know but synthesizes what I've learned over that time.  Hopefully others can fill in the gaps provided they can make it all the way through this post  

 

The 210-220hp range is an inflection point.  Going beyond that puts you on the precipice of a steep, slippery slope thanks to piston-to-valve clearance limitations.  Although you can "simply" pocket the stock pistons, that need leads many to do the as-long-as-I'm-in-there dance, resulting in new, higher compression, forged pistons that can already handle the higher lift, forged rods, keyed crank, fully balanced bottom end, headwork, etc.  Been there, done that, and have no regrets.  Depending on cams, you can comfortably get to the 235-260hp range without resorting to a forged crank and short rebuild cycles.

 

The most verified power I've heard an engine make with 420 equivalent cams, Jenvey's, and headwork was 226hp.  Most, however, come in the 210-220hp range.  Heads are another consideration.  I've been unable to determine which of the two Duratec heads are fitted to the 420.  The early 2.3L from the Ranger and all US 2.0L use the same version, but when Ford added the 2.3L to the Focus in the US, they changed the head to something people later coined the high-port.  The casting is different and accommodates larger intake ports; specifically, the area over the valve guide is increased.  Ford of Europe used this head on the 2.0L in the Fiesta ST150 and possibly others, but I've never seen that casting on any US-based 2.0L.  The stock head is good for about 220hp, removing a small exhaust tumble intended for emissions increases this to about 235hp, and the stock high port flows to 250hp.  You can modify the low-port head to close most of that remaining gap.  Some claim the high port head is an immediate 10+hp upgrade on any engine.  Others state you need to have an engine already in that 220hp range to start seeing an improvement.  I've never seen before/after data either way.  There is also the 2.5L head which has enormous intake ports, and is bolt on, but does require some additional work to fit a se7en.  I've also never heard stock power potential, but as the person who does my heads told me, the stock flow is less than one would expect based on the visuals.  250-260hp maybe?

 

The reason the head matters is if the 420 uses the high-port head, you could probably knock on the door of 230hp with your current engine by adding roller barrels or throttle bodies, a good custom map and optimizing cam timing on the dyno.  You'd probably be 5-10hp less if it's the low-port head.  This is a lot easier, cheaper, and far less time intensive than rebuilding the engine as described above.  It really comes down to the age-old question, how fast do you really need to go and how much do you really want to spend?

 

-John

[MV8]

Instead of engine mods, consider setting up a spare diff with numerically higher gearing appropriate to the course. Much more cost effective and you can go back to original easier.

[KnifeySpoony]

6 hours ago, MV8 said:

Instead of engine mods, consider setting up a spare diff with numerically higher gearing appropriate to the course. Much more cost effective and you can go back to original easier.

Yeah but then you have to change the diff all the time which is a massive ball-ache on these cars lol. 

[MV8]

Everybody wants to go to the party, but nobody wants to clean up after......

How about an entry level 5 psi regulated turbo setup with rising rate regulator, small oil cooler, and no intercooler. Waste gate integral. Bov if you want to add one.

 

 

[fastg]

My projects have a life cycle, a long term plan. Adding a turbo will probably be the final iteration. MV8 is right a low pressure turbo system would be simple and cost effective. Medium size turbo, you don't want one that spools up to quickly, nor do you want a large turbo that will cause to much lag, Garrett 6262 with a .83 exhaust housing is the favorite at the moment. Good waist gate priority to allow low pressure spring to be affective. I was thinking of a 4 pound base spring increasing to 8 pounds to higher rpm. 8 pounds would give me about 400rwbhp, so maybe a 6 pound max boost.  I don't think an intercooler will be requires if you have good starting IAT. Or I could phone 4 Piston and order the 1000bhp all day setup:)

 

Graham 

[JohnCh]

I took a look in an exhaust port of my uninstalled 420 engine, and it appears to match SBD's photos of the high-port head with the bump out around the valve guide.  

 

-John

[sf4018]

Thanks all especially @JohnCh for the suggestions and info, so to summarize these are the options...

1. Rebuild engine with new pistons and other internals.

2. Add Roller Barrels or Throttle Bodies

3. Replace Diff.

4. Entry level 5 psi regulated turbo setup with rising rate regulator, small oil cooler, and no intercooler. e.g. Garrett 6262.

 

I think I'm gonna focus on 2 for now, seems the easiest for my limited skill and tool set.

 

[fastg]

A Garrett 6262 would suite my K24 Honda engine, it would be to large for your Duratec. I would not buy a Garrett for your situation, hell I would not buy one for my car, very expensive. There are a lot of good Chinachargers available, you can probably get a ball bearing turbo for $600 a Garrett would be closer to $1900. 

 

Graham 

Edited August 15, 2023 by fastg
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[JohnCh]

1 hour ago, sf4018 said:

1. Rebuild engine with new pistons and other internals.

2. Add Roller Barrels or Throttle Bodies

 

I think I'm gonna focus on 2 for now, seems the easiest for my limited skill and tool set.

 

 

The advantage of this approach is that if you later opt for #1, you will already have the induction set up in place.  The big decision is Roller Barrels or Throttle Bodies.  TBs are a lot cheaper ($1500 - $2000 vs. >$5000) but they aren't necessarily a straight bolt-on and they don't have the same cachet of RBs at resale time.  It might be worth a call to Raceline and speak to Peter (call the tech line) to get his thoughts and the latest on pricing.  They use the Jenveys which work very well.  If you do decide to go that route, ping me offline and I can walk you through some things at order time to save a few headaches.

 

-John

[Drakman]

Hi Guys,  I cannot for the life of me remember where i found the following information, i think it was on a ford focus forum.

 

There are 2 part numbers (cast into the exhaust side ) that signify the Hi port head design :- RF6S4E and RF3S4G

 

The engine in my 2014 roadsport 175  is a DHE420, which apparently means it is 107KW and 190NM.  It has the RF6S4E cylinder head fitted. 

 

Take the above as "might be right", i make no guarantees as to the accuracy of it.

 

Does anyone know where i can get a Cosworth big valve ported cyl head?

 

Cheers

Dave