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ECU knock option worth it?
http://forum.diyefi.org/viewtopic.php?f=6&t=2850
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Author:  dfarr67 [ Tue Mar 27, 2018 3:37 pm ]
Post subject:  ECU knock option worth it?

In my other vehicles the ecu or tuner was plug and play with known oem hardware- even then the engine on one is noisy enough to cause false knock issues. I'm looking at https://controls.is/shop/ecu/lpc4 by Baldur and it has a knock expansion board for an extra $200 (this buys a group of options) just wondering if it is worth while- on the other vehicles I had the stock starting point, here you would have to build the file (Toyota 22RE turbo application). I think I know the effort involved in tuning knock and will be ordering a configuration soon.

Author:  Fred [ Wed Mar 28, 2018 12:40 pm ]
Post subject:  Re: ECU knock option worth it?

Probably depends on how consistent your fuel supply is and how extreme your seasons and seasonal fuel variations are.

If your cooling system isn't particularly tight it could also be helpful as chamber temperature and valve temperature have a direct impact on knock.

I've personally run my low output engine up to knock, backed off JUST enough to prevent it, and driven like that for years without it recurring, so in NZ I reckon the fuel is consistent enough to not bother.

I'll link Baldur here so he can add his 2c - he's about as straight up as you'll find so it's unlikely to be self-biased :-)

Author:  dfarr67 [ Wed Mar 28, 2018 3:50 pm ]
Post subject:  Re: ECU knock option worth it?

Sounds like his knock routine isn't ready yet and I'm on the fence on waiting for the option. temps range from -30C to +30C here, application is turbocharge (low boost) 1990 4runner 4x4 with the 22RE. cooling is via Evans coolant and V6 rad. No E85 here but there is winter rated fuel. Baldur's competition right now is the (local tuner) ProEFI 48, but for some reason although I like the oem like hardware- I have a bad taste about the company- I have had no dealings with them, just research. I like knock protection, I want it, but I understand its a undertaking by itself.

Author:  Fred [ Wed Mar 28, 2018 8:22 pm ]
Post subject:  Re: ECU knock option worth it?

It's also of limited use on more extreme stuff, however if you're aiming for super efficient then it might be useful to run your timing intentionally into knock and let the ECU back off as required (one of the big reasons why the OEMs have it).

Author:  dfarr67 [ Wed Mar 28, 2018 10:39 pm ]
Post subject:  Re: ECU knock option worth it?

I don't feel that I would want to take it that far and really lean on it, maybe for a bad tank of gas or some such. Super efficient and 4x4 are an oxymoron ;) Although I do like lean cruise/highway mode.

Author:  baldur [ Thu Mar 29, 2018 10:57 am ]
Post subject:  Re: ECU knock option worth it?

I have tuned hundreds of cars and only used knock control on very few of them actually. I always monitor knock during tuning to make sure I am not too close to knocking at full load.
The thing with knock control is it needs careful calibration to make it work, and some applications don't lend themselves to making it work (too much mechanical noise). You need to make the engine knock on purpose to test the knock detection. I have found that on modified engines, even with just small modifications like swapping into a different chassis with solid engine mounts, the OEM knock calibration does not work well, usually picking up false signs of knock.

In my opinion, knock control is essential in two scenarios. Scenario one is a mass produced car that needs to be able to run safely and efficiently regardless of what fuel is put in the tank, from 85 octane and up. There the knock control will let the ECU adapt to the different fuels. Scenario two is a racing class with spec fuel, where the knock control will let the ECU keep the engine designed to push the spec fuel to its limits from blowing up.

In other applications it is certainly nice to have but it does need careful calibration to do any good at all.
Outside of some competitive racing applications, it is a good idea to begin with to make sure the tune is not too close to the knock threshold, and for the same power, it's safer to run one more psi boost than to advance the timing closer to the knock limit.

Author:  dfarr67 [ Thu Mar 29, 2018 6:06 pm ]
Post subject:  Re: ECU knock option worth it?

Baldur, since you brought up the octane issue I have a general question. Carbon tax here has really boosted pricing of fuel and I am thinking about retuning two existing vehicles back to 87.

1/ 1989 chev 4x4 383 with TPI currently tuned with 90 octane, AFR vortec heads (decent chamber design), 9.5:1.

2/ 2015 Honda Accord 2.4L 6MT DI tuned for 90 octane.

Is either of these vehicles is it worth the extra cost to run 90? Is there a payback in mileage?

87 here $1.20/L
90 +$0.10/L

Author:  baldur [ Fri Mar 30, 2018 10:41 am ]
Post subject:  Re: ECU knock option worth it?

There really isn't a great difference between 87 and 90 octane. You may see a slight difference in low speed torque with 90 octane and an even smaller difference in fuel economy but on an engine that's not super high compression they'll make the same power up top.

Author:  dfarr67 [ Sun Apr 01, 2018 8:41 pm ]
Post subject:  Re: ECU knock option worth it?

I want an opinion. I don't plan on running high boost, I had the TB bored out and it has worked ok for na, I thinned out the shaft myself- I aslo JB welded everything together- and I'm kind of looking at this sidewise, I have a spare TB should I go back to stock or change out the shaft- for robustness.

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