Direct Injection for a 914 Type IV?, Whose going to try it first? Options

[Brian Mifsud]

My office mate pisses me off daily... "35MPG" he mumbles as we walks past my cube...

He owns a new 2014 Mazda 3, a 3000lb car with a 2.5L 4 using direct injection. Our commutes are both in town.

My 2007 Honda fit, a 2400lbs, 1.5L Port Fuel Injection... I can't get better than 30MPG!

He tells me he's running around with a 13:1 compression ratio on REGULAR gas... (Fit is 10.4:1)...

Okay, I'm sold on Direct Injection's advantages...

We've seen adaptations of various VW Fuel Injection Systems on the Type IV... anybody got the bug to try and build a Directly Injected, Mass Airflow and Oxy Sensor managed motor?

[TheCabinetmaker]

Gas mileage? Who cares? Mazda 3? Who cares? Besides that, he probably lies.

[stugray]

Get a FA20 out of a BRZ (FRS).
It is 4cyl, Boxer, 2.0L, direct&port injected with 12.5/1 CR and variable valve timing
I get 30 MPG in the BRZ.

Then you can ridicule him for having ONLY Direct injection.
Tell him "Good Luck with those carbon deposits!! HA HA"

The Direct only engines have a problem with carbon buildup on the intake valves.
The combo port/direct cleans off the carbon.

Oh, and my Passat TDI gets 54 MPG.

[Brian Mifsud]

Carbon Buildup on the Intake Valve is definitely NOT intuitive. I'd expect if any to be on the injector itself, but I understand that when you run 20Kpsi..nothing is gonna stick to that blast.

Why the Intake Valve? Just because it is constantly cooled?

[jd74914]

Interestingly, the first motors retrofited with direct injection performed much worse than their port injected counterparts. Cylinder head and piston top really designs need to be optimized for DI since there is no port pre-mixing. I met some guys from a German university who converted a Honda CBR600RR motor to DI and found performance to be much worse, even after quite a bit of optimization. The other issue is that there aren't too many engine controllers out there suitable for controlling the DI pump (Syvecs, MoTeC M1 series come to mind), so you are a little limited on controls.

Variable valve timing is really where performance lives. With many modern VVT and VVL systems you can continuously "optimize" air movement through the engine and reduce pumping losses, charge contamination, and throttling losses. It's almost to the point that a TB is not necessary (see BMW VANOS where there is no conventional throttle body; it's only used for major flow throttling and all fine tuning is in the valve lift/timing).

The really cool part about DI for me is that since there is no port fuel wetting you can extensively control torque with fuel flow. Port injected engines either just use spark timing to control torque (only useful to about a 20% reduction), or have some torque reduction/increase delay because of fuel supply delay when using fuel cuts for torque reduction. DI injections don't have this problem so almost all torque reduction (literally 60-80% is possible) can be done with fuel. This means that traction control on racecars retains fuel efficiency. AER wrote a great article about it in terms of their LMP2 engines.

Port and direct injection like the BRZ is definitely the way to go!

[messix]

i read white paper a while ago on D/I. there is a whole lotta black magic that goes into those motors.

VVT, throttle by wire, ign timing insane fuel pressures.

the throttle on those runs like a diesel wide open at light/cruse load.

every thing is controlled by how much fuel, when it's injected and when the ignition fires and the cam phase/ timing.

some serious wizards design those engines. (IMG:style_emoticons/default/blink.gif)

[messix]

the "carbon build up' is the oil on the valve stem that doesn't get washed off or burned off in the case of the exhaust valves.

it's more of a gummed up build up.

my nephew had the do the "cleaning" on his turbo cobalt ss, get this they air blast walnut shells into the intake port to clean it. and then shop vac it out.

[veekry9]

Certainly the first aircooled type.
I would think the greatest difficulty would be being able to run the high compression and lean mixtures possible as with the watercooled.
A variation on the theme is an LPG (Propane)conversion that used a chamber injector.
From what I've read of the adiabatic cooling characteristics of the gas the method may have some distinct advantages over gasoline.
An informative treatise on the method was written by Smokey Yunick,and entertaining.
http://www.smokeyyunick.com/--------------- -------------- Buy this 1100 page book.
http://www.legendarycollectorcars.com/feat...xclusive-video/
http://www.hotrod.com/how-to/engine/hrdp-1...t-vapor-engine/
https://www.google.ca/#q=smokey+yunnick+fuel+injection

[r_towle]

Interestingly, the first motors retrofited with direct injection performed much worse than their port injected counterparts. Cylinder head and piston top really designs need to be optimized for DI since there is no port pre-mixing. I met some guys from a German university who converted a Honda CBR600RR motor to DI and found performance to be much worse, even after quite a bit of optimization. The other issue is that there aren't too many engine controllers out there suitable for controlling the DI pump (Syvecs, MoTeC M1 series come to mind), so you are a little limited on controls.

Variable valve timing is really where performance lives. With many modern VVT and VVL systems you can continuously "optimize" air movement through the engine and reduce pumping losses, charge contamination, and throttling losses. It's almost to the point that a TB is not necessary (see BMW VANOS where there is no conventional throttle body; it's only used for major flow throttling and all fine tuning is in the valve lift/timing).

The really cool part about DI for me is that since there is no port fuel wetting you can extensively control torque with fuel flow. Port injected engines either just use spark timing to control torque (only useful to about a 20% reduction), or have some torque reduction/increase delay because of fuel supply delay when using fuel cuts for torque reduction. DI injections don't have this problem so almost all torque reduction (literally 60-80% is possible) can be done with fuel. This means that traction control on racecars retains fuel efficiency. AER wrote a great article about it in terms of their LMP2 engines.

Port and direct injection like the BRZ is definitely the way to go!

Jim,

Could you please design me an aircooled motor, adapted with today's technology. (IMG:style_emoticons/default/biggrin.gif)

[colingreene]

You wont feel so good about the port/DI combo once you get the oil analyzed and realize how much gas is in the oil
Who cares if he drives a Mazda 3.

[Dave_Darling]

Heh--I know people who can get 50 MPG out of a Fit... MPG ain't everything, and you have a huge influence over what you get by how you drive.

--DD

[thelogo]

True that man let me guess

Faster u go the worse the mileage

The more the wind resistance (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/smash.gif)

[veekry9]

The guts of it.Hasn't been installed into a 914 to date.AFAIK.
http://www.ft86club.com/forums/showthread.php?t=17247
https://www.google.ca/#q=FA20
http://jalopnik.com/5918932/the-wait-for-t...s-crash-is-over.

Could be a challenge to give the T4 a new lease on longevity and efficiency.

[stugray]

the "carbon build up' is the oil on the valve stem that doesn't get washed off or burned off in the case of the exhaust valves.

it's more of a gummed up build up.

All engines have at least some "scavenging" where the intake valve begins to open when there is still positive pressure in the cylinder.
So some combustion by-products see the back of the intake valve.
In a port injection engine the fuel will keep this cleaned off.

The BRZ does kind of sound like a diesel and also has a very loud high pressure fuel pump driven off the cam.

[a few loose screws]

Someone would have to do a boat load of R and D to fit DI to a type 4 engine. you'd need to mount a whole whack of sensors , new pistons so the ultra lean burn would work correctly, not a mater of just machining a random size pocket into the piston either, I imagine you'd need to break out the old slide rule for that one. I'd have to say, you'd be a bit nuts to try, But nutty people keep things interesting. Neat technology, very diesel-esque. I took a training course a few months back on tier 4 final diesel engines, its funny how these engines are, in some ways, becoming more like petrol engines and at the same time the DI petrol engines are using diesel technology.

[rhodyguy]

so his car runs approx 50 miles further on a tank of fuel. less than 2 gallons of fuel saved. big deal. do you own your 07'? casually ask what his 2014 mazda payments are.

[Java2570]

My 2010 Fit consistently gets 35-36 mpg.....driven daily in urban stop & go traffic. And I do not drive conservatively....

[Mikey914]

I would think the major disadvantage is the cooling of the fuel in the intake. Without it, I would think that you would have to add additional cooling capacity.

[veekry9]

What a great idea Mike,a liquid cooled head for the T4,DOHC 4V,DI.
Crank trigged,variable timing and anything else I can think of.


https://www.youtube.com/watch?v=zcPGfjUO3Yg

https://www.youtube.com/watch?v=E3v2lBpeZPc
https://www.youtube.com/watch?v=78QrZyQInnk
http://www.hotvws.com/news2.php?contentID=70
https://www.linkedin.com/pub/brian-hyerstay/10/b62/93
http://www.kval.com/news/local/Rare-1946-V...-222742581.html

[Brian Mifsud]

My 2010 Fit consistently gets 35-36 mpg.....driven daily in urban stop & go traffic. And I do not drive conservatively....

You're killing me.......

I drive JUST in town but on Country Highways.. 8 miles to work, usually average about 45-50 MPH (School Zones and Speed Limits).

I bought a Fit 'Sport' which has 55 series tires, but hardly Steamrollers. ( I own the car BTW, bought it new in 2007 to replace me worn out '96 Mustang GT).

Wife insisted on an automatic (5 speed) for the 3 times a year that she drives it... ( (IMG:style_emoticons/default/hissyfit.gif) )

I accelerate smoothly (proof that I can drive smoothly.. I got 190K miles out of my Mustang GT original clutch....)

I can't crack 30 MPG in town... shit!!!

Okay, I do weight 240lbs (am working on that).. but comeon....