What's that? More air from Project Evo's upcoming bigger turbo won't do squat if we don't have the fuel to go with it?
Hang on. Can't we just tell our stock injectors to stay open longer?
Yes and no.
Think about fuel injectors this way--if you're not near the limit, you're fine. Bigger injectors won't do a lick of good if the ones you have are not operating near their limit. And that limit is 100%. I'm talking about duty cycle, or the percentage of time that an injector is being told to inject fuel.
The other limit is imposed by an injector's dead time, or the amount of time it takes to dislodge the metal bit that blocks and unblocks the hole inside the injector through which fuel blasts on its way into your engine.
Right, then. Yes, we were already near the upper limit with the stock injectors when we were on the stock turbo. Our injector duty cycles were reaching about 90%, leaving little headroom to support more airflow.
The stock Evo injectors flow around 560 cc/min. By doing some simple math and adding in some margin, we want our new injectors to be at least 720 cc/min. But what if we want to go crazy with E85? Not saying we will, but it'd sure be nice to have that option. In that case we'll need an injector in the 1000 cc/min range.
Injector Dynamics not only makes a set of 1000 cc/min injectors that are "plug-and-play" for the Evo X, they go a step further.
Remember all that talk about dead time? Injector Dynamics are crazy about dead times. Nuts.
Any injector provider will match a set of injectors for you based on max flow, but Injector Dynamics is the only one we're aware of that also matches injectors based on their dead time.
There's a great writeup on their site on the effects of dead time, so I won't try to reiterate that here. Just know that Injector Dynamics are injector nerds of the first order.
Tony Palo of T1 Race Development is the head pimp of all things Injector Dynamics, and he sent us the injectors and adapters you see above.
Plus, Tony included a printout of injector dead time vs voltage and pressure for these injectors that will be very handy when Road Race Engineering rescales the injectors in the Evo's ECU.
MSRP (ID1000 injectors + adapters): $548.00
Jason Kavanagh, Engineering Editor
shaddai says:
06:08 PM, 08/21/09
I'm not a mod guy, but reading these posts kind of makes me wish I had gone with an Evo X instead of an S4 (B7)...
cwmoo740 says:
06:19 PM, 08/21/09
Even more rexpensive toys! This is going to cost a whole lot when you get this stuff installed.
spdracerut says:
08:00 PM, 08/21/09
Nah... the fuel injectors are a piece of cake on the Evo X. My 4 year old niece could do it. The only install job so far that I would not try myself would be the clutch job.
altimadude00 says:
08:16 PM, 08/21/09
There goes the fuel economy.
ricerocketeer says:
04:14 AM, 08/22/09
I've got the 725cc versions in my boosted RSX. Fuel economy isn't bad at all, as long as I stay out of boost.
demosthenes642 says:
04:35 AM, 08/22/09
So where's the COTW suspension walk around?!
nasag03 says:
10:52 AM, 08/22/09
do you need special injectors that are compatible with E85? my understanding is that ethanol will degrade certain rubber compounds and stock petrol-compatible rubbers will need to replaced for the fuel system.
i'm guessing this would include injector seals, injectors, fuel lines, fuel pump, and fuel pressure regulator.
nasag03 says:
10:58 AM, 08/22/09
do you need special injectors that are compatible with E85? my understanding is that ethanol will degrade certain rubber compounds and stock petrol-compatible rubbers will need to replaced for the fuel system.
i'm guessing this would include injector seals, injectors, fuel lines, fuel pump, and fuel pressure regulator.
skunkworks says:
10:04 PM, 08/22/09
"do you need special injectors that are compatible with E85? my understanding is that ethanol will degrade certain rubber compounds and stock petrol-compatible rubbers will need to replaced for the fuel system."
Depends, alot of newer vehicles are intentionally over-engineered to withstand even high levels of ethanol, although it is corrosive. Keep in mind that most summer blends of unleaded gasoline is E10, or 10% ethanol. Independent testing tends to find that normal gasoline generally has some where between 5-20% ethanol, many times gas stations will use an excessive amount of ethanol if it is cost effective to do so, as ethanol can be much cheaper to produce than gasoline in certain parts of the country.
E85 and turbo charged engines are a very good fit for each other, as turbo charged engines in effect have somewhat variable compression ratios, allowing a properly tuned engine to take advantage of varying combinations of ethanol and petrol that occur in most E85 blends.
And of course it's dirt cheap compared to race fuel, and is actually 20-30% cheaper than premium fuel where I live (Phoenix)
I'd love to see the IL staff convert this Evo to E85, my GSR is currently tuned to run a 91/E85 blend and it has performed wonderfully.
skunkworks says:
04:15 PM, 09/14/09
It's been three weeks... did you guys wreck your Evo?
Give us an update, can't leave us boost junkies hanging.