Installing 320 amp alternator to 2016 2.5 should I get an ecu tune??? :confused:

I’m installing an apex alternator 320 amp in my 2016 Subaru Legacy 2.5 l. They said you could get a Ecu tune to raise the idle, but it isn’t required. I’m just wondering what the trade offs are if I don’t get the tune? Could the car end up not running correctly without it? Also wondering how much it would cost doing something like that would be for a car that doesn’t have many mods made for it.

 

 

If you have any thoughts or suggestions that’d be greatly appreciated

 

Thanks, have a great day

 

-Rad

 

 

12/5/19 --- Interesting development today - we installed a 1000cca battery to test the difference to see if that was the main issue. While it did improve the peak before cutting out it didn't solve the issue. Another thing he thought it possibly might be is the positive connector that connects to the terminal itself being to loose or somehow being screwy i guess. So next time i see him with the improved battery we are going to replace those connectors entirely. the positive may be the issue, as we connected my battery back to it and torqued the posi down very tight worked for a few seconds then started to cut out again. So this whole issue might have been that the connector was not right when we put the 1000 cca battery on.

Edited December 5, 2019 by Radmandan2
new development

The first big question is, "Why do you think you need a 320 amp alternator?" Second question, "Is it compatible with the Legacy's battery management system, in which the ECU modulates the alternator's output voltage under different conditions?"

 

That said, I would strongly recommend that you not mess with the ECU. If it ain't broke, don't fix it.

Edited December 3, 2019 by ammcinnis

The first big question is, "Why do you think you need a 320 amp alternator?" Second question, "Is it compatible with the Legacy's battery management system, in which the ECU modulates the alternator's output voltage under different conditions?"

 

That said, I would strongly recommend that you not mess with the ECU. If it ain't broke, don't fix it.

 

 

Well, its a complicated story, but I have two 15" nvx subwoofers hooked up to a Hifonix brutus brx 3016.1 d amplifier wired at 2ohms 2000 watts max rated.

(side note: in test on youtube

the current pull at 2ohms to 1% thd was 128.4 amps, my stock alternator puts out 130 amps at full load. on the dynamic test which fits the music i listen too the amp pulled 150.3 amps. so i figure by that, i could use the alternator anyway and or that could be the whole issue.)

 

I'm having an issue where the volts to the amplifier are dropping and causing the amp to go into protect mode. I had the system installed at connected car audio in NH. He's been in the business a long time, but who knows what that means. He does seem very knowledgable though, and i did not have any issues with the system until ab 8 months after the install i brought it back to him and he changed the ground location and it was working fine apparently but then it got home and stopped working again. (this is the most recent occurence) Another interesting little quirk ab it was that when it first happened i switched out my brand new hifonix amp (which worked for 8 months) with my brothers old one (same model) it worked fine until the amp combusted and smoked till dead, ab 5 days later. after ab 2 months, I bought another brx 3016.1 d and it worked fine for a couple of days then the same issue arose again although this time the amp did not blow up and still is working. My thought on that is that the amp was probably used to his system in a way or it was just being under powered. The first thing that comes to mind is a new battery deep cycle 800cca optima yellowtop havnt ordered that though as i have to fabricate a new battery tray. the reason i think it may be the battery not having enough power is because after i take the positive off for a while (a few weeks) they seem to work for a bit at any volume, not always at full, but as i explained after ab two months of no extra load they worked for three days no limit. at this point they are working at a low level less than 25% of what they should be able to run at. whenever i go any higher the amp cuts in and out.

 

Anyway the alternator stock is clutched and runs at 130 amps at full capacity. i also just wanted piece of mind in the future because i did have dimming issues beforehand when the system was running. The alternator was also on a 200 and some odd # sale so i sent it.

 

I apologize for the long winded response, but I'm just trying to give you all the details, im really in a tough spot here unfortunately and any help is greatly appreciated.

 

Thank you,

 

Austin.

Edited December 3, 2019 by Radmandan2

Well, its a complicated story, but I have two 15" nvx subwoofers hooked up to a Hifonix brutus brx 3016.1 d amplifier wired at 2ohms 2000 watts max rated.

(side note: in test on youtube

the current pull at 2ohms to 1% thd was 128.4 amps, my stock alternator puts out 130 amps at full load. on the dynamic test which fits the music i listen too the amp pulled 169.4 amps. so i figure by that, i could use the alternator anyway and or that could be the whole issue.)

 

I'm having an issue where the volts to the amplifier are dropping and causing the amp to go into protect mode. I had the system installed at connected car audio in NH. He's been in the business a long time, but who knows what that means. He does seem very knowledgable though, and i did not have any issues with the system until ab 8 months after the install i brought it back to him and he changed the ground location and it was working fine apparently but then it got home and stopped working again. (this is the most recent occurence) Another interesting little quirk ab it was that when it first happened i switched out my brand new hifonix amp (which worked for 8 months) with my brothers old one (same model) it worked fine until the amp combusted and smoked till dead, ab 5 days later. after ab 2 months, I bought another brx 3016.1 d and it worked fine for a couple of days then the same issue arose again although this time the amp did not blow up and still is working. My thought on that is that the amp was probably used to his system in a way or it was just being under powered. The first thing that comes to mind is a new battery deep cycle 800cca optima yellowtop havnt ordered that though as i have to fabricate a new battery tray. the reason i think it may be the battery not having enough power is because after i take the positive off for a while (a few weeks) they seem to work for a bit at any volume, not always at full, but as i explained after ab two months of no extra load they worked for three days no limit. at this point they are working at a low level less than 25% of what they should be able to run at. whenever i go any higher the amp cuts in and out.

 

Anyway the alternator stock is clutched and runs at 130 amps at full capacity. i also just wanted piece of mind in the future because i did have dimming issues beforehand when the system was running. The alternator was also on a 200 and some odd # sale so i sent it.

 

I apologize for the long winded response, but I'm just trying to give you all the details, im really in a tough spot here unfortunately and any help is greatly appreciated.

 

Thank you,

 

Austin.

 

When i asked the Apex people they said that it is compatible with my car and wont trip an engine light. i also found this manufacturer thru another subaru legacy owner with a 3.6 r on one of my earlier post. he said he had one of theres installed with no issues but it was a 3.6 so i guess i dont know for sure. Again if your still reading, thanks

 

Rad.

sounds like you need a capacitor for your system, not an alternator..

 

https://www.crutchfield.com/S-57S8w76VrIs/learn/car-what-is-a-capacitor-faq.html

sounds like you need a capacitor for your system, not an alternator..

 

https://www.crutchfield.com/S-57S8w76VrIs/learn/car-what-is-a-capacitor-faq.html

 

well that would make sense, but everyone i have talked to and the research ive done suggest that it would just put more stress on the charging system which is already maxed so from what ive researched it wouldnt even be able to charge.

 

I appreciate the suggestion and will do some more research.

Edited December 3, 2019 by Radmandan2

you don't have a charging issue, you have a draw issue. definitley get the optima battery and a Capacitor, or even 2. maybe wire your setup for 4 ohms as well.

Anyway the alternator stock is clutched and runs at 130 amps at full capacity.

FWIW, the stock alternator is indeed rated at 130 amps, but it doesn't have a clutch.

 

You do not need a new, high-capacity alternator. Your situation is an issue of peak load vs. average load. The alternator only has to satisfy the average load, while the battery (and an optional capacitor, if installed) supply extra power for the peaks. The things to look for in your case are: 1) Is the battery healthy? 2) Is the power and ground wiring large enough? Voltage drop in the power wiring will cause some of the problems you report. 3) Is the power wire attached directly at the battery? Is it properly fused? 4) Are power and ground connections clean and tight? 4 AWG copper wire would probably be the smallest I'd choose as a starting point for a 150 amp circuit. Voltage drop depends on both wire gauge selected and total wire length (power + ground).

 

FWIW ... Assuming reasonable speaker efficiency, the average power necessary to provide music listening in a large room at LOUD levels is only about 5 watts ... less than 1 amp at 12 volts, even allowing for amplifier efficiency. I know; I've measured it myself ... back when broadcast and professional audio was my primary job. On the other hand, peak power demand may be much higher, but it's only required for the narrow transients like percussion. (A 1 kW peak is ~23 dB louder than 5 W.)

 

N.B. If you're indeed pushing 1 kW (peak) to the speakers in an automobile, you are inflicting permanent damage on your hearing. That's a bad idea, but it's your car, your hearing, your choice.

 

 

The attached photo is of the prototype for a 200 watt (100 watts per channel) linear power amplifier of my own design ... from many years ago. The enormous heatsink was left over from another project.

Edited December 4, 2019 by ammcinnis

FWIW, the stock alternator is indeed rated at 130 amps, but it doesn't have a clutch.

 

You do not need a new, high-capacity alternator. Your situation is an issue of peak load vs. average load. The alternator only has to satisfy the average load, while the battery (and an optional capacitor, if installed) supply extra power for the peaks. The things to look for in your case are: 1) Is the battery healthy? 2) Is the power and ground wiring large enough? Voltage drop in the power wiring will cause some of the problems you report. 3) Is the power wire attached directly at the battery? Is it properly fused? 4) Are power and ground connections clean and tight? 4 AWG copper wire would probably be the smallest I'd choose as a starting point for a 150 amp circuit. Voltage drop depends on both wire gauge selected and total wire length (power + ground).

 

FWIW ... Assuming reasonable speaker efficiency, the average power necessary to provide music listening in a large room at LOUD levels is only about 5 watts ... less than 1 amp at 12 volts, even allowing for amplifier efficiency. I know; I've measured it myself ... back when broadcast and professional audio was my primary job. On the other hand, peak power demand may be much higher, but it's only required for the narrow transients like percussion. (A 1 kW peak is ~23 dB louder than 5 W.)

 

N.B. If you're indeed pushing 1 kW (peak) to the speakers in an automobile, you are inflicting permanent damage on your hearing. That's a bad idea, but it's your car, your hearing, your choice.

 

 

The attached photo is of the prototype for a 200 watt (100 watts per channel) linear power amplifier of my own design ... from many years ago. The enormous heatsink was left over from another project.

 

 

Thank you for your concern for my hearing, i appreciate that.

 

2)The amp is wired with 0 gage wire both positive and negative.

 

Interesting development today - we installed a 1000cca battery to test the difference to see if that was the main issue. While it did improve the peak before cutting out it didn't solve the issue. Another thing he thought it possibly might be is the positive connector that connects to the terminal itself being to loose or somehow being screwy i guess. So next time i see him with the improved battery we are going to replace those connectors entirely. the positive may be the issue, as we connected my battery back to it and torqued the posi down very tight worked for a few seconds then started to cut out again. So this whole issue might have been that the connector was not right when we put the 1000 cca battery on.

 

Anyhow Progress has been made,

 

1)he tested the battery on a snap on battery tester and was healthy i believe only having lost 1 amp from the 375 it originally had. now 374

 

3) The positive is connected to the connector screwed d He actually upgraded the ground wire that connects to my neg terminal. The positive is correctly fused. Another weird thing is the startup voltage dropped i think it was about 11.4 at the amp connection when just turning the ignition from 12.4 i think up front... https://imgur.com/a/RKpl5g2 : shows where the power wire hooks too.

 

(https://www.virustotal.com/gui/url/b1fe915b01bd095afa1ab5ce7ed4acc46e5ef730294047822ba45ef37287a51b/detection)

 

the amp is dropping the startup voltage by a full volt, i forget the actual #'s i will call him tomorrow and put those up here. We called hifonix and the guy we had on the line was no help unfortunately. That dropping of a full volt confused the hifonix guy aswell. it just doesn't make any sense that its the amp though as it happened with another amp granted it was the same model but that same amp works just fine in my brothers car.

You want a Odyssey Battery not an Optima and I've researched Apex Alternators as well and will be getting one for my audio.. Our stock Alternators are 170 amps.. Apex is going to make me a 360 amp they actually come with a smaller pulley so at Idle it's output is 14.4volts so in most Audio Systems peak power of amps are rated at 14.4v.. The alternators are regulated so at driving speed it wont over charge.

 

Sent from my SM-G965U using Tapatalk

You want a Odyssey Battery not an Optima and I've researched Apex Alternators as well and will be getting one for my audio.. Our stock Alternators are 170 amps.. Apex is going to make me a 360 amp they actually come with a smaller pulley so at Idle it's output is 14.4volts so in most Audio Systems peak power of amps are rated at 14.4v.. The alternators are regulated so at driving speed it wont over charge.

 

Sent from my SM-G965U using Tapatalk

 

What's it regulated to? With very little load on the alternator (e.g., driving for extended periods without the amp drawing power), I wouldn't want to see anything above 14.4VDC.

 

Even while charging my batteries, I won't leave them at 14.4VDC for longer than ~ 24 hrs. At 14.4 VDC, when charging amps drop to nothing or 24 hrs later, I drop the voltage to 13.9VDC for maintaining 100% capacity.

 

Even if you have the amp drawing max power, if the alternator is putting out closer to 15VDC (or higher), your battery may start gassing, since 15VDC is equalizing voltage for most 12VDC LA batteries.

Our stock Alternators are 170 amps.

Nope. The OE alternators are rated at ~130 amps max. (Source: 2015 Factory Service Manual)

 

. Apex is going to make me a 360 amp they actually come with a smaller pulley so at Idle it's output is 14.4volts ...

The output of the OE alternators at idle is typically above 14 volts. Current available at idle is less than 50 amps, though, increasing with rpm. (Source: 2015 Factory Service Manual; personal measurement)

 

The alternators are regulated so at driving speed it wont over charge.

I've never seen an automotive alternator that wasn't regulated. Some regulators are internal, while some are external. Most modern cars (including the Gen 6 Legacy) implement "battery management systems" that are considerably more complex than simple single-setpoint voltage regulation. Edited December 6, 2019 by ammcinnis

I would try installing a second battery before installing a HO alternator. Search for xp2500, it's a 100 amp hour battery designed to supplement up to 2500 watt system. Also have you installed the Big 3 Upgrade?

I would think having a large-capacity optima battery wired in a series that also feeds into 2 / 3.0 farad capacitors would be way more than sufficient for your sound system this is how I had my previous vehicle wired and I never had any issues. At the time I was running Alpine type x subwoofers pushing much higher wattage than your current setup but again the point was I was still under max load.

I would think having a large-capacity optima battery wired in a series ...

I think you mean "wired in parallel" ... i.e. positive-to-positive, negative-to-negative. (The difference is important!) Even then, it's not a good idea to connect batteries (especially mismatched batteries) directly in parallel without a battery isolator in the circuit.

 

Parallel batteries in an Outback could be even more problematic, given that the Outback's battery management system includes a sensor to measure current flow into and out of a single battery.

Edited December 18, 2019 by ammcinnis

I think you mean "wired in parallel" ... i.e. positive-to-positive, negative-to-negative. (The difference is important!) Even then, it's not a good idea to connect batteries (especially mismatched batteries) directly in parallel without a battery isolator in the circuit.

 

Parallel batteries in an Outback could be even more problematic, given that the Outback's battery management system includes a sensor to measure current flow into and out of a single battery.

 

Sorry correct in parallel otherwise you will be doubling voltage and cca in a series setup which could potentially cause a fire. Adding fuse blocks 18in before battery is a good idea as well. Now in regards to the battery management I didn't have a problem on my previous 13 legacy but not sure how it would apply to other models.

I checked out apex and it looks like the alternators are build to order I was wondering how much yours cost? On a side note I still need to run power through the firewall for amps and was wondering if you could post a pic of where you drilled. Preferably a pic from the engine as well as by the pedals figuring I’ll most likely be drilling out from inside the car.