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DIY Fuel injection thread.


yoeddynz

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Just now, Roman said:


Having the correct injector data for example, can make night and day difference to how well all of your compensation tables work.

this is probably going to lead me to buy brand new injectors from a reputable source for the new corona engine, 

the mitsi injectors were great, but alot of the info was sourced from seedy mitsi forums or guessed. plus a while back i had a wiring fuckup which when the car/ecu was turned off, the injectors were held open. and although i didnt notice anything majorly wrong, that cant be good for them lol. would dump the fuel rail into the cyliders and be an absolute bastard to start, no matter how any settings i fiddled with. which backs up alg193s comment about efi not being a magic fixall if your still an idiot :tongue:

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Dont forget accel enrichment. God that took me ages to fiddle into the right place.

DIY-ing an EFI system isnt about whats "easy" to throw together for magic results, thats what a chequebook EFI setup is for. DIY is about fiddling with everything and learning what everything does, even if that is from making mistakes or taking bloody ages to stop it running like a bag of dicks. There is nothing like that feeling when you finally nail that part of the tuning you have been having issues with. I really enjoy that part of it, seeing the results of what your changes.

In regards to buying a car with a cheap DIY EFI system in it, the guy that bought Effie with my Speeduino fitted couldnt care less what is in there, just that it runs and drives well. He isnt going to play with it, or change anything. It would've made no difference if it had the standard EFI in it or not. I guess it might be different if its a car that would attract the sort of owner that would fiddle with stuff?

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Just now, kws said:

thats what a chequebook EFI setup is for.

Most chequebook setups I've encountered run the worst.

With regards to accel enrich, I struggled immensely with it until I invested in a good quality TPS and then the problem instantly went away.

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Off topicish but the hondata for K24 shit is super cool, keep all factory features but open up the ECU to full live tuning. Car even has built in wideband which makes shit so easy. Learning curve is steep to learn how Honda does the knock control and to make sure it isnt fucking with your changes. That and tuning 5 fuel tables for the variable cam timing is interesting.

A great resource for all sorts of ECU tuning is this Evan guy:

https://evansperformanceacademy.vhx.tv/

Sign up for a month and rip the videos you need, has full series of him live tuning all sorts of cool shit. Certainly gets you up to speed fast.

 

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Just now, ajg193 said:

With regards to accel enrich, I struggled immensely with it until I invested in a good quality TPS and then the problem instantly went away.

This seems to be a big part of your issue with DIY setups tbh. A DIY setup doesnt mean it needs to be done as cheap as possible with the shittiest secondhand/knockoff parts.

I used good quality parts and had no issue with any of my hardware, any issues I had were user error.

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Anyone done any fuel economy tuning with a cat converter involved? Old cars I have fucked with with EFI had no cat so you can tune lean at cruise for some pretty decent economy gains. With the cat involved you are meant to aim for 14.7 at cruise so you don't cook it. I wouldn't trade off removing a cat as cars are smelly as fuck without em, but its interesting that modern cars don't use the lean cruise thing as it fucks emissions/cats. Guess they get better economy numbers though more efficient engine design etc.

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Well this topic would lead you to believe you're a horrible person if you buy any brand new components and spend more than $500 all up on an EFI conversion. TBH I didn't know the first TPS I bought was a knockoff, it was listed as genuine on trademe, when it lasted only a short time I was like 'fuck it. I'm not spending another $50 or $60 buying another supposedly good sensor when I can just take a risk and get 2 for $15 from China' - the ones from China were probably from the exact same factory. When I finally bought a genuine one I was surprised to feel the difference in quality, it weighed twice as much and was built far better.

The reason I didn't get a TPS from pick-a-part is that the Starlet throttle body required a sensor with a very specific and uncommon shaft diameter and rotation direction so I couldn't find anything. Turns out LS-1 sensors fit the bill quite well.

/end rant

Does anyone want to buy an Innovate LC-2 wideband controller? I've found them to be perfectly reliable in an industrial setting. No sensor included though.

 

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Just now, Spencer said:

Anyone done any fuel economy tuning with a cat converter involved? Old cars I have fucked with with EFI had no cat so you can tune lean at cruise for some pretty decent economy gains. With the cat involved you are meant to aim for 14.7 at cruise so you don't cook it. I wouldn't trade off removing a cat as cars are smelly as fuck without em, but its interesting that modern cars don't use the lean cruise thing as it fucks emissions/cats. Guess they get better economy numbers though more efficient engine design etc.

I've read that modern catalytic converters can cope quite happily with non-stoic mixtures but they just cost more.

Edit: I'm wrong. I'm gonna do some more reading.

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Just now, ajg193 said:

Most chequebook setups I've encountered run the worst.

With regards to accel enrich, I struggled immensely with it until I invested in a good quality TPS and then the problem instantly went away.

The big problem with Chequebook set ups is budget.

Paying someone to tune your entire set up from Cold Start, to Full Load Power run, along with VVT maps and associated varying conditions is unrealistic cost wise. It takes hours. At between $100 - $200 an hour or more. Let alone if they're installing components and building custom wiring looms.
 

Only drug dealers have the kinda spare cash lying around for a professional tuner to build and tune an engine management system from scratch, and end up with a system that has 80 - 90% of the startabilty, driveability and reliability of a factory ECU.

Also they're constantly blamed for Failures, so on top of that, usually have super safe ignition tables and wildly rich fuel maps. Which itself starts causing problems.

Like anything you can get 70% of the result with 30% of the effort. The last 30% takes time, patience and understanding.

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Just now, Spencer said:

Anyone done any fuel economy tuning with a cat converter involved? Old cars I have fucked with with EFI had no cat so you can tune lean at cruise for some pretty decent economy gains. With the cat involved you are meant to aim for 14.7 at cruise so you don't cook it. I wouldn't trade off removing a cat as cars are smelly as fuck without em, but its interesting that modern cars don't use the lean cruise thing as it fucks emissions/cats. Guess they get better economy numbers though more efficient engine design etc.

So there are just different tricks to acheive the same thing.

Essentially what you're trying to do is increase the airmass relative to fuel amount, but its the excess of oxygen that now causes problems. 

So VVT engines can use cam timing to introduce overlap. Which means non oxygenated hot air can flow back in from the exhaust and increase the airmass without the nasty side effects that usually come from running very lean.

The party trick of this, is that you can do so while still acheiveing stoich and keeping the cat happy. And reduce emissions by an absolutely incredible amount compared to normal lean burn.

This is why VVT cars either need a MAF sensor, or like the hondas have a million tables for cam angle. 

Because your MAP sensor value goes up or down based on how much EGR effect is happening. 

I was running a MAP based tune and then realized this was fucking everything up, so thats why I went to MAF. 

So now that I've got both sensors, look at how you can see the MAF value can stay stable while the cam advances. But the MAP reading fucks right off when EGR comes along (so at about the 30 deg advance mark in this case) 

3750rpm.PNG.91fd455d55cc4f2d6842d2715fa2667f.png.70220517a5877b564c74694738e6bbbe.png

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No but I've read up a lot on it. 
Generally you can add up to around 15% EGR before you start getting misfires. 
Some of the factory high EGR engines like Audi V10 use a coilpack that fires off 5 times after first being triggered. 
As this helps (EGR saturated) lean burn situations ensure there's a full burn.
So effectively delays the misfiring to a higher EGR percentage.
It's worth noting though that injecting EGR into your intake manifold is grotty as fuck, especially on diesels. 
I'd not be so keen on doing EGR that way.

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Just now, ajg193 said:

Have any of you played with EGR (using a valve instead of cam timing) and studied the effects on fuel economy? I feel that could be quite a fun avenue to go down

EGR is used to reduce Combustion Temperature and intern reduce Nox formation at the outter perimeter of the combustion chamber.

My understanding is that it is purely for Emissions Reduction and does not improve Fuel Effeciency. 

 

I stand corrected.

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Constantly. It's my day to day job fixing those stupid things.

On a petrol engine they contribute to fuel economy quite effectively, exactly how Romans graph shows. They reduce intake vacuum which decreases pumping losses. Modern engines take it a step further with their direct injection swirl valves by seperating the inert EGR gas to the outside of the cylinder and the air/fuel mix in the centre for a more efficient burn. It also allows for more EGR gas to enter the cylinder to "pack it out" as such.

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Just now, Yowzer said:

Constantly. It's my day to day job fixing those stupid things.

On a petrol engine they contribute to fuel economy quite effectively, exactly how Romans graph shows. They reduce intake vacuum which decreases pumping losses. Modern engines take it a step further with their direct injection swirl valves by seperating the inert EGR gas to the outside of the cylinder and the air/fuel mix in the centre for a more efficient burn. It also allows for more EGR gas to enter the cylinder to "pack it out" as such.

I wasn't under the impression that EGR was used in a Lean Burn - Startified Charge Situation. 

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Just now, japawagons said:

I wasn't under the impression that EGR was used in a Lean Burn - Startified Charge Situation. 

They call it a Stratified EGR Combustion System. Probably a bit newer or something. I went down a rabbit hole awhile back haha

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