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Mechman 370 Amp Alternator

Discussion in 'Product Reviews' started by freudie1, Sep 13, 2021.

  1. Sep 13, 2021 at 3:05 PM
    #1
    freudie1

    freudie1 [OP] New Member

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    Ok here goes:

    2014 Tundra 5.7 liter. I have a very extensive stereo system (endless hobby) that is a total of approximately 3500 watts rms.

    Dual Northstars (custom, one under hood, one under bed), big 3, 400 amp relay, all that fun.

    I installed the Mechman 370 amp alternator for this truck.

    The install: Sucks, but if you have ever replaced an alternator in these trucks you know that. None the less all things considered it went in fine.

    NOTE: You DO have to install a slightly smaller belt (I used a Gates belt from NAPA, part # 080944 or 8PK2399).

    The good:

    Voltage gauge doesn't budge! I can set the truck to whatever voltage I want and it sticks right there (I created a custom device that commands whatever voltage you want and maintains that voltage).

    So, no more dimming headlights, voltage doesn't sag, amps are happy.

    The bad:

    IDLE! So this is where it goes a bit south. The alternator comes equipped with a 1.75" diameter pulley (hence the need for a slightly shorter belt).

    This works OK as long as your idle speed is approximately 650 rpms or higher.

    Soooo...."What rpm DOES my truck idle at?" you might be asking.

    Here goes:

    I have HP Tuners software in hand. I have verified that the idle is controlled in two conditions:

    In park/neutral vs engine coolant temperature.

    In gear vs engine coolant temperature.

    The issue is when in gear and the ECT is above 60 celsius. By DEFAULT (read stock), 60 C + in the in gear idle table = 550 RPM idle.

    Clearly this wasn't a tested product on the Tundra (or very quickly tested before the ECT got above 60 C).

    SOLUTION: Via HP Tuners I modified the in gear idle at 60C + to be 650 RPMs. Yes, this slightly increase gas consumption, but I would argue barely unless you are idling at stop lights for ages or stuck in stop and go traffic for hours.

    REAL SOLUTION: The alt should have came with an even smaller pulley, then again I have no idea if the 1.75" diameter pulley supplied is as small as will fit on the snout of this alternator (I have an email/complaint into Mechman right now to figure out what the story is here).

    Long story short: Alt works great, just have to increase in gear idle to get proper stop light/stop sign charging abilities. Not impressed with testing (or lack thereof).

    One more minor gripe: I asked in my order notes if they knew the part # for a "slightly smaller belt" as this was indicated as being required with this alt. Their response? Nothing. Once again, makes me think this wasn't tested (or their customer support is poor).
     
  2. Sep 13, 2021 at 3:33 PM
    #2
    Danimal86

    Danimal86 Looks clean even when its dirty!

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    Welcome!
    You cant drop this kind of info on us, and not show us the system or at least a list of all the components!
    I've had the car audio bug for quite some time and my single northstar 27f has been working well for me, but i'm only pushing about 1800w max (doubt it ever puts that much out)....mines more sq than spl.
     
  3. Sep 14, 2021 at 9:19 AM
    #3
    freudie1

    freudie1 [OP] New Member

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    So as suspected they didn't test this alternator (or at least fully test it, read: Wait for the ECT to reach 60+ Celsius). Here is the response I just got from support:

    "The 46mm pulley is the smallest one we have available. So if you have the ability to modify that idle speed it would be the way to go."

    Translation: You can't use this alternator unless you have the ability (read: buy a tuning product such as HPTuners) to modify the ECU to raise the in gear idle speed.

    Sad. I've asked for a discount, but I will be surprised if one is offered. I manufacture/sell electronic devices and I couldn't imagine not testing something to this basic level then selling it.
     
  4. Sep 14, 2021 at 9:32 AM
    #4
    crewmaxlmt

    crewmaxlmt How dare you!

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    You might try DC Power. Their alternator puts out 180-200 amps at idle and the description does not mention using a smaller pulley.
     
  5. Sep 14, 2021 at 9:39 AM
    #5
    freudie1

    freudie1 [OP] New Member

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    No pictures readily available (old image hosting site is gone). I'll take some in a few weeks after I finish the latest modifications and updates (never ending).

    In a nutshell it is the following:

    Mechman 370 amp alt

    Dual NorthStars (actually the rebranded ones from Batteries/bulbs/etc place, same deal though).

    400 amp relay connecting the two (one battery is underhood, the other is under the bed in a "drop down" box from some hot rod company kit I found). 00 gauge throughout.

    ImageDynamics HLCDs (horn loaded compression drivers) with Beyma CD10nd compression drivers

    JBL 2118H 8" midbasses that I have in custom fiberglass/upholstered kick pods I built from scratch. That was fun (they are 15 lbs a piece after I added a ton of ball bearings and resin milkshake to get the resonance issues solved).....I should have taken pictures when I built these. I welded nuts to a metal plate to make removal of the drivers easier).

    JL 10TW3's: 3 in a sealed under seat enclosure (DC, so limited options unless I go blow thru which I am debating: Think "tool box" in bed but with a sub enclosure inside...saw this done years ago in another truck, very stealth but very pricey).

    Amps: Phoenix Gold Xenon 100.4 bridged for the two 2118h's, Phoenix Gold Xenon 1200.1 for the subs, Linear Power DPS 200 for the horns. I'm replacing the LP amp with an Alpine amp as an experiment. Also the 1200.1 amp I am replacing with an Orion XTR25001.dz this weekend.

    Processor: Helix DSP Pro

    Head unit: OEM non-jbl!

    Essentially this is an old school tribute install with a 2-way horn/midbass front stage and some fairly old school amps (well for now that is...once again I'm swapping some amps out for a few reasons, think SNR issues in combination with very high sensitivity horn drivers causing a bit of hiss).

    Other thoughts, I'm not in love with the 10tw3's. Their low end sucks. It is what it is with shallow mount woofers hence I think my box in a box blow thru is in my future this winter if I get the itch.
     
    619Tundra likes this.
  6. Sep 14, 2021 at 9:44 AM
    #6
    freudie1

    freudie1 [OP] New Member

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    I'd rather deal with a slightly higher idle than RnR an alternator in a Tundra again. VERY unpleasant experience.

    Mechman is now claiming this:

    "
    We have sold over 100 of these and this is not something that we have experienced even with the low idle speed of that Tundra. Also, with our unit being large case and the stock unit being small case the taller centerline of the alternator makes up the small difference in belt size.


    A belt that is too short can make the tensioner not perform properly and result in some belt slip, is there any signs of belt slip on the alternator like heavy belt dust residue on the front of the alternator or any of the anodizing worn from the ribs of the pulley".

    Comedy. I am literally using the next size belt down available from the oem belt. No slipping, no "dust", heck it works great once idles get above 600 RPMs (and one would think I would have slipping WORSE as the rpms increase).

    I shot back he needs to find out who tested these alts with the Tundra and IF they tested the idle/voltage relationship in gear with ECT's at operating temps. I know the answer...even told him I suspect they tested this at idle in PARK (which is how competitors in sound comp lanes would run) since of course that would not show this issue (the stock ECU calibration commands approximately 750 rpm idle at 60+ C ECTs)....

    Once again, this alt DOES work (and well I might add), just has an output issue at in gear idle unless you modify the ECU like I did.
     
  7. Sep 14, 2021 at 9:53 AM
    #7
    freudie1

    freudie1 [OP] New Member

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    More fun. Now the support tech is telling me "the belt would only need to be .4 inches shorter than stock”.

    NOTE: The belt I am using is only .6 inches shorter than stock. Two tenths of an inch is easily taken up by the tensioner. Too funny.

    Full update, now he admits: "
    Actually I think that belt size would be within range. I think the stock size would be in range as well, when I first read your belt size I misread and 1.1 inches would be a problem but the .6 inches should be ok even with the taller centerline.

    "

    So once again...they didn't test in gear with normal ECTs. Lord, just admit you F'd up.
     
  8. Sep 14, 2021 at 10:22 AM
    #8
    Danimal86

    Danimal86 Looks clean even when its dirty!

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    I had to google what the HLCD's were...where the hell did you mount these?
    upload_2021-9-14_10-16-31.jpg

    Sounds like a pretty crazy setup. Cant wait to see pics! Cool that you got 3 of the subs under the seat, is it ported or sealed? I'm running two of the 10tw3's in a ported enclosure. I had them in the sealed stealthbox before and they really need to be in a ported enclosure.

    I'm also running the helix dsp pro mk2 and two 5ch amps, 3 way active up front and passive rears. I'd be interested to see how your graphs look like on the dsp.
     
  9. Sep 14, 2021 at 10:44 AM
    #9
    freudie1

    freudie1 [OP] New Member

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    I found some old pics of the truck install here: https://www.phoenixphorum.com/viewtopic.php?f=10&t=25348

    HLCD's aren't hard in the Tundra to mount other than you will have to lose the e-brake lever on the driver's side (can't recall the last decade I even used one...and if you really care you COULD install an aftermarket electronic actuator for the cable). If you haven't heard them you should. My image is dead center at the windshield. People think I have a center channel when in reality I don't have ANY of the speakers in the dash hooked up. Also gets brutally loud if you want it to (think front row AC/DC concert levels).

    In the pics in that post you will see the passenger side one. I covered the horn openings in grille fabric to make them less obvious. The kick pods are huge due to the 2118's needing .5 cu ft each (they are sealed pods).

    Subs are in a sealed box. I previously had 2 in a ported box for JRT/Randy/etc....he miscalculated the port size and it sounded like a one note wonder. I like boom, but also SQ (i.e. SQL style install). The 10tw3's just don't have the grunt that full size subs do no matter what I do. I'm already eyeballing my sheet metal saw.....
     
  10. Sep 14, 2021 at 11:13 AM
    #10
    Danimal86

    Danimal86 Looks clean even when its dirty!

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    Thats super cool! Man, those pods are chonkers...I bet your midbass is outstanding though....midbass can be a mf'er to get it right. Amp rack looks really nice. You should definately do a blow through. Throw a couple w6's or w7's in a bed box and that thing would be nuts!

    You doing all the helix tuning yourself? I've done about 5-6 tunes on my setup and its still a work in progress (learning as i go). I'm in the process of going through and setting the gains on the helix and amps using a handheld oscilloscope. Once i do that, i'm going to hopefully do my final tune.

    Here's my build log if you you are looking for some bathroom reading, a little long in the beginning but plenty of pics.
    https://www.tundras.com/threads/the-stereo-slow-build-begins.17397/
     
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