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DIY Fuel injection thread.


yoeddynz

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It's weird though I would have thought that an uneven intake manifold would only really pose an issue when you're at full throttle and the engine is trying to consume as much as possible.

When you're at part throttle one cylinder doesnt really have a mass flow advantage over another?

What injectors are in there, is this the car with those single pintle 1000cc?

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33 minutes ago, Roman said:

It's weird though I would have thought that an uneven intake manifold would only really pose an issue when you're at full throttle and the engine is trying to consume as much as possible.

When you're at part throttle one cylinder doesnt really have a mass flow advantage over another?

What injectors are in there, is this the car with those single pintle 1000cc?

These are xSpurt 1000cc/rebranded ID1000s, not the china 1000's

The pressure drop difference occurs at all rpms,  the blower puts 1.6L of air in every rotation of the engine but its easier for that air to get into cylinder 1 and 2 than 3 or especially 4, so even though only 1 inlet valve is open at a time there will still be a difference, more residual pressure in the manifold than reaching the cylinder in a given time. As rpm increases and there is less time for the air to move, the relative difference may change slightly one way or the other (not sure which way). As pressure increases with boost the relative difference will be less.

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35 minutes ago, Roman said:

Oh so is it more to do with lobe pulses and when you get that burst of air, rather than unequal runners?

 

I don't think it's about unequal runners at all? The runners are all equally short and the injectors are near the runner's inlet. I think the issue (in theory) is the log plenum causing a pressure difference between the runners and potentially having the front cylinders stealing fuel from the rear ones. 

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yup, not to do with lobe pulses but the log. as said runners are basically non existent and #1 is directly infront of the S/C and #2 is very close but #3 and #4 are two 90 deg right turns and 75mm and 150mm of  log away at 45mmish diameter, which is about the same as the port and valve sizes.

The lobe pulses may have some other effects, and the bypass valve is between #2 and #3 so that will have some other effects too.

just all about solving problems no one else ever has because of one else has been silly enough to persist with quite the same setup.

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  • 2 weeks later...
21 hours ago, scooters said:

facepalm..

 

"my car hasnt had 02 sensors in.. forever. it roams around in a open loop speed density tune. killing small children and raping helpless mothers at night."

 

Carburetors are open loop and work just fine

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2 hours ago, tortron said:

kiwi Holden vn and VP v6s never had O2 sensors or cat converters. 

Run slightly better in Aussie because of it

Did my time at Holden in ozz Caloundra.. 

Use to get told a lot about how the police pack stuff had ECM's that was tuned for more power (loads of shit) all the kids were pining over BT1 chassis codes. (1" lowered suspension" ) 

ohh God love the OBD1 ROM chip days. 

 

 

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I use my wideband only for logging not fuel trim.

It over/undershoots a lot in reaction to itself because of sensor latency (and no fuel film model in ecu) and makes oscillations when otherwise id only have a small % error.

There are some settings I can adjust to make it less sensitive but really need to adjust in real-time which is hard without a 2nd person to drive.

 

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Chinese LSU 4.9 came today.

 

Looks different to OE 4.9 but works perfectly so far (seems bang on in terms of accuracy, faster warmup time than OE). Will be interesting to see how long it lasts, but can't complain too much at $43.

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megasquirt 1 (2.2) question. 

on my old engine i had the radiator fan handled by the ecu no problem, but ever since i switched to the twincam it hadnt worked, (it may just be that this is when i first noticed too)

i had it setup to trigger a relay from the (-) side of LED18. but now when ever i hook up the relay to it it turns the LED off, if it was on. the ecu software is functioning properly switching the output on and off ect. 

i measured voltage at that neg pin and its ~2.5v when the led is off and ~5v when the led is on. it never seems to switch to ground like i thought it was meant to. 

any ideas whats going on here? maybe i fired the transistor somehow. 

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  • 2 weeks later...

14point7 spartan 2 came today.

 

Pulled out the LC-2 and put the 14point7 in, it's 100x better. There is no signal noise now, the sensors that the LC-2 reckoned were dead work fine, warm-up time is like 15 seconds.

 

I am using closed loop EGO control for the first time now, set with authority of 5%. Seems good so far, map is within 1% in most situations anyway. There is no way I could have used closed loop with the LC-2, it was just too unstable.

Chinese sensor is still working perfectly.

 

Now I just need to find some industrial application for the LC-2 / from my experience they seem reliable enough in low demand environments.

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