“Ambulance” is 80 minutes of pure mayhem wallowing through 140-150 minutes of pure Michael Bay hokum.

The action sequences are assaultive, brutally-efficient exercises in gunplay, stunts and frenetic acting passing by in a blur as breathless as the editing team can make it, all of it set to a thundering pulse-pounding score by Lorne Balfe.

The the whole movie is glib, with a police SIS captain in tattered USC gear driving his drooling mastiff around in a vintage Fiat 500 spouting flippant dialogue, with only the rarest line standing out. The plot goes completely off the rails.

And the casting is archetypal, one long Bay cliche.

Jake Gyllenhaal turns on the “crazy Jake,” with Yahya Abdul-Mateen II (Manta in “Aquaman”) in the “good half-brother corrupted” sidekick role, Eiza González as this year’s Megan Fox, playing a kidnapped paramedic and Garret Dillahunt as a Josh Duhamel substitute — the cop/authority figure given to bragging that “We’re SIS…we set traps” for bad guys. “That’s how we do it.”

It opens with an emotional gut-punch and ends with an attempted reprise of that. But most of what comes in between is a life-is-cheap/nobody-ever-needs-to-reload gunfight and crash-crash-crash (in more or less real time) car chase.

Given all that, knowing that things are going to get real stupid at some point, with characters quoting Michael Bay movies (“The Rock,” “Bad Boys”), and acknowledging that the 2:16 advertised running time is an understatement, do you give yourself over to Bay’s latest non-“Transformers”/”Bad Boys” ride?

Maybe. But you’ll hate yourself in the morning.

Abdul-Mateen II plays Will, a Marine vet with a sickly wife, big medical bills and an unhelpful military insurance complex letting him down. But his “brother,” the guy whose father “took me in,” might help. Even if his wife keeps Danny’s (Gyllenhaal) phone number blocked and warns Will away.

Sure, Danny’ll help. But not with a job helping him guard a rich client’s car collection and working as a sort of flunky/personal assistant. No, Danny’s got “a score” lined up. It’s about to go down right now. You in?

Combat vet Will finds himself in a supposedly souped-up delivery van with Danny and a bunch of strangers pulling off a $32 million bank robbery in downtown LA.

The heist goes off as an homage to Michael Mann’s “Heat,” with that one unplanned interruption that springs a massive police response. Nobody shouts “It’s a TRAP!” because there isn’t time.

Hundreds of rounds are expended, robbers drop one by one, and then it’s just improvising Danny, assuring his brother that he’ll “get you home,” hijacking an ambulance that’s shown up to save a freshly-shot cop.

EMT Cam (González) is another hostage, trying to save the bleeding-out policemen as Will drives the wheels off that ambulance through the crowded streets, freeways and down the oft-filmed LA River, chased by a “Blues Brothers” supply of crashable police cars and some seriously audacious police helicopter piloting.

The jaw-dropping moments come early — Cam’s first paramedic call of the day involves a child impaled in a car crash — and almost often enough to keep us invested. There’s a hilarious cell phone/Facetime “consultation” on a grisly bit of mid-chase back-of-ambulance surgery and the choppers swoop in so low they almost sandblast the paint right off the ambulance.

But once the picture goes seriously over-the-top and Jake pays for “help” in their escape, there’s no coming back. It’s the worst of the “Fast and Furious” movies (same Dodge product placement, same Latin car culture) in Michael Bay form.

Dillahunt is the “my day off” SIS (Special Investigations Section) captain who mismanages the chase at every turn, Olivia Stambouliah is his mouthy tech/coordination assistant and Keir O’Donnell is the gay FBI agent who leaves couples-counseling to get in on the action.

“He is looking for a way out,” the Fed says, stating the SCREAMINGLY obvious.

“How do you know that?” Captain can’t-see-the-obvious replies.

Dillahunt can’t make lines like his character’s “chess match and a cage fight” analogy funny, because they aren’t. And he generally isn’t, either.

“Ambulance” is based on a Danish thriller from 2005 which I recall seeing, but don’t recall being Danish so maybe not. It can’t have stumbled along the line between self-parody and just-plain-nuts that this does.

But Gyllenhaal knows a thing about blowing up a performance to match the mayhem around him. And if Yahya Abdul-Mateen II isn’t turned into some level of “star” by his toe-to-toe-with-Jake turn, at least he’ll force a lot more of us to remember how to spell his name.

As for the movie, just add the word “stupid” to “guilty pleasure” and you’ll have it covered.

Rating:  R for intense violence, bloody images and language throughout

Cast: Jake Gyllenhaal, Yahya Abdul-Mateen II, Eiza González, Olivia Stambouliah and Garret Dillahunt.

Credits: Directed by Michael Bay, based on the German film “Ambulancen.” A Universal release.

Running time: 2:16