FORD has really kicked a goal in Australia with its latest-gen Mustang. Sales are up, we see a bunch of them on the road and there are plenty of enthusiasts looking to get that little extra out of the stock 5.0-litre Coyote engine.
This article was first published in the July 2019 issue of Street Machine
The Coyote really is a gem of a powerplant. As far as stock-bottom-end performance goes, it’s the king, hands down. Plenty of workshops have been offering aftermarket performance options for these motors, but the boys from Northmead Auto Centre have really been on their game when it comes to developing these engines without opening them.
Their 2015 Mustang has made an astonishing 1060rwhp with 16psi of boost on a stock engine, with the only mod being the addition of billet oil pump gears. That’s right, a totally stock motor with a couple of 60/62 Precision whizzers attached.
Unlike an LS, which needs a different cam, head bolts, valve springs and head gaskets (at a minimum) to make a great boost combination, the Coyote has variable cam timing controlled by the ECU. This makes it perfect as a Drag Week-style package as there are no lifters, pushrods or any of the usual valvetrain failures to worry about.
To date, the Northmead 2015 ’Stang has run 9.1@151mph, on stock suspension and running on radials, and the car is full-weight!
Not prepared to rest on their laurels, the team has its sights set on another goal: to run a 10-second pass in a full-weight, stock-suspension, naturally aspirated 2018 Mustang, with zero modification to the factory engine. Seems impossible, right?
Yet through re-tuning the engine and transmission, Northmead’s ’18 Muzzy has so far run an 11.1@126mph with a totally stock motor/auto combination and weighing 3900lb.
In stock trim the 5.0-litre makes around 240kW at the rear wheels – pretty stout for a small engine. The great thing about the motor is the overhead cam configuration, which means it can rev to around 8500rpm. Another advantage of the 2018 model over the earlier versions is that it is equipped with both direct and port injection, so it has excellent down-low torque with the direct injection, and power with the port injection. Its predecessor only had port injection and came with a six-speed rather than a 10-speed auto.
To begin with, the Northmead crew found the factory ECU quite a challenge. Nobody seemed to have any experience locally or overseas and all the Americans offered was a locked tune you could buy, so your car would go quicker, but never quicker than the tune allowed. Not good enough.
It took quite some time for Northmead head tuner Tyson Munro to get a handle on the factory tune, and they started by doing their own flash tune, which really didn’t make any difference. “We quickly realised that the factory headers are very restrictive and the exit on number-eight cylinder is just bloody horrible,” Tyson says.
“We started with a set of bolt-on Pacemakers and then built our own custom mid-pipe section. We wanted to keep the car as quiet as possible and retain all the factory features, so we built the rear tailpipe section to incorporate the bi-modal exhaust motor.”
The bi-modal exhaust is basically an electric exhaust cut-out that is controlled by the ECU and changes with each performance function or setting.
After a fresh tune, the car responded with a huge 40rwkW increase, punching the total power to around 285kW.
In standard trim the car was pretty quick, clicking off a 12.5. After the flash tune and exhaust system upgrades it was into the 11.50s, but constantly struggling over the 60-foot.
“Then we went to an E85 tune, and with the massive fuel system fitted to the car from the factory we didn’t need to touch the pump or injectors; we just tipped the fuel in and re-tuned it,” says Northmead Auto Centre owner Bill Tzavaras. “Even on E85, the injectors are only at 34 per cent duty cycle; win-win!
“The high static compression ratio of 12:1 and E85 mix made it perfect to bump some more timing in, and at points we have added up to six degrees, which added another 10 per cent overall and left us with 314kW at the tyres.”
Just to put that in perspective, that’s over 400rwhp – about what a GTHO Phase III made at the flywheel.
“The car comes with a factory transbrake/launch control, but even on the big 305 radials it just blows them off,” Bill says. “We tried changing wheels and taking all the extras, junk and personal effects out of the car, and it went 11.40s. Our biggest gain by far was the E85 tune, which put the car right into the 11.1 zone. If we could just get the car into the 1.5s in the 60-foot it would be a 10.6 car.
“But we are pretty happy really,” Bill concludes. “We know it will go a 10 in the next meeting or two, so for about $9K a customer can drive in and drive out with a 10-second street car.”