Why did Ford choose the GT350IM for the Bullitt?

[Meatball]

If this has already been discussed to death, apologies.

There seems to be an impression out there that the GT350IM has zero advantages over a stock 18GT IM, in the low/mid range and even for peak power for a Coyote to 7500rpm (not Voodoo). There's a Car Craft article out there on a crate GT Gen3 motor (though tuned for E85 and with a CAI + non-stock TB), which shows the 18GT IM meeting or beating the GT350IM, including for peak power, to 7500rpm:

https://www.hotrod.com/articles/dyno-every-ford-coyote-intake-manifold-on-gen-3-crate/

I know the 18+ manifold is significantly revised & improved from the Gen2, and there are folks out there that know via Ford staff that no advantage to the GT350IM, but if that's the case why would Ford/FP choose it for the 19 Bullitt knowing full well how the 18IM performs? Does the IM contribute to the power bump over the GT or is it all in the CAI/TB/tune? It just seems nuts that they'd do that for no good performance reason.

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[Meatball]

If this has already been discussed to death, apologies.

There seems to be an impression out there that the GT350IM has zero advantages over a stock 18GT IM, in the low/mid range and even for peak power for a Coyote to 7500rpm (not Voodoo). There's a Car Craft article out there on a crate GT Gen3 motor (though tuned for E85 and with a CAI + non-stock TB), which shows the 18GT IM meeting or beating the GT350IM, including for peak power, to 7500rpm:

https://www.hotrod.com/articles/dyno-every-ford-coyote-intake-manifold-on-gen-3-crate/

I know the 18+ manifold is significantly revised & improved from the Gen2, and there are folks out there that know via Ford staff that no advantage to the GT350IM, but if that's the case why would Ford/FP choose it for the 19 Bullitt knowing full well how the 18IM performs? Does the IM contribute to the power bump over the GT or is it all in the CAI/TB/tune? It just seems nuts that they'd do that for no good performance reason.

By the way, I DO believe FP chose the GT350IM for valid performance reasons, I’m just trying to understand why.

 

[Schwerin]

For a fair comparison we'd also have to see those test run with a BULLITT ECU as we don't know what was changed in the stock tune vs a GT. My suspicion is that the GT350 let the powerband be extended a small bit.

I find it hard to believe that a retuned ECU, intake, TB and IM would have almost 0 change.

I'd like to see on the same day, same dyno the total of 3 stock GT runs vs 3 stock BULLITT runs, then the graphs overlapped.

 

[Whitemagic1]

If this has already been discussed to death, apologies.

There seems to be an impression out there that the GT350IM has zero advantages over a stock 18GT IM, in the low/mid range and even for peak power for a Coyote to 7500rpm (not Voodoo). There's a Car Craft article out there on a crate GT Gen3 motor (though tuned for E85 and with a CAI + non-stock TB), which shows the 18GT IM meeting or beating the GT350IM, including for peak power, to 7500rpm:

https://www.hotrod.com/articles/dyno-every-ford-coyote-intake-manifold-on-gen-3-crate/

I know the 18+ manifold is significantly revised & improved from the Gen2, and there are folks out there that know via Ford staff that no advantage to the GT350IM, but if that's the case why would Ford/FP choose it for the 19 Bullitt knowing full well how the 18IM performs? Does the IM contribute to the power bump over the GT or is it all in the CAI/TB/tune? It just seems nuts that they'd do that for no good performance reason.

Cheap. Easy to get 20 HP from parts already designed and made.Its making more power, so , it works. You're answering your own question( CAI/TB/tune). Unless you want exact answers from Ford engineering.And I cant see the comparison that Car Craft did. Why not use a stock setup. How can you compare "tuned for E85 and with a CAI + non-stock TB ? I dont see that test as a fair comparison. IMO...

 

[Meatball]

For a fair comparison we'd also have to see those test run with a BULLITT ECU as we don't know what was changed in the stock tune vs a GT. My suspicion is that the GT350 let the powerband be extended a small bit.

I find it hard to believe that a retuned ECU, intake, TB and IM would have almost 0 change.

I'd like to see on the same day, same dyno the total of 3 stock GT runs vs 3 stock BULLITT runs, then the graphs overlapped.

Right!

Cheap. Easy to get 20 HP from parts already designed and made.Its making more power, so , it works. You're answering your own question( CAI/TB/tune). Unless you want exact answers from Ford engineering.And I cant see the comparison that Car Craft did. Why not use a stock setup. How can you compare "tuned for E85 and with a CAI + non-stock TB ? I dont see that test as a fair comparison. IMO...

It's consistent with the past two generations of Bullitts, where bits of the intake system were swapped out for a small gain in power. I have a feeling FP needed to go all in (CAI, TB, IM and tune to make them work) to get a reasonable power bump because the Gen3 is so optimized out of the gate, for a 12:1 engine that needs to be able to run on 87 octane. The big, easy gains for the Gen3 is an E85 tune. But as for the IM, there MUST be some power to be gained from that choice because it doesnt help low/midrange torque at all compared to the stock one.

 

[obspsd]

As far as the intake manifold goes, it was mostly just for marketing.
I believe there was a video a while back where a Ford engineer said as much.

 

[Tony Alonso]

You paid for engineering development time from the manufacturer of the engine parts to optimize across the system. They figured out packaging, reliability, emissions, and performance characteristics to extract more power from the higher revving set-up.

A custom manifold would have likely not been financially feasible or easy to do within the timeframe they had.

As you said, each previous Bullitt was enhanced in the power department in a similar way. Adapting something that was able to be amortized more easily is probably the business way to think of it. Adapting something that is packaged in the available space without the use of an engine cover and that worked together with a larger air element is probably the engineering way to think of it.

 

[aileron]

As far as the intake manifold goes, it was mostly just for marketing.
I believe there was a video a while back where a Ford engineer said as much.

Please post a link, and offer an alternative explanation for the 20 SAE HP delta between a '19 GT and '19 Bullitt.

 

[obspsd]

Please post a link, and offer an alternative explanation for the 20 SAE HP delta between a '19 GT and '19 Bullitt.

Still can’t find what I was looking for, but below are a couple screenshots with mostly accurate info.

 

[Zooks527]

Please post a link, and offer an alternative explanation for the 20 SAE HP delta between a '19 GT and '19 Bullitt.

Well, it does give a HP bump, but that bump only occurrs over 7000 rpm or so in higher gears where the stock GT IM becomes the flow limiting point. If you're out someplace where you'll be over 145 mph, the HP difference is real. If you're a street or strip driver, you'll never see any difference. That being said, it does let Ford claim a higher value for the Bullitt in their marketing materials.

 

[GreenS550]

I had 3 4.6 S197 GTs: 2005 auto, 2007 GT/CS and 2009 Bullitt. They were stock when I bought them used. The Bullitt was unquestionably the slowest. With a tune and summer tires it ran 13.6 in the 1/4. I know a lot of folks want to believe the intake makes more power on the Bullitt but it simply does not. Less low end torque, too. It's just that the 19 Bullitt dyno graphs show the car at higher RPMs to get the add'l HP.

That doesn't take away the coolness of the current Bullitt. Ford did it all very good. Fun as heck to drive, but the low/middle RPM torque is lacking. Just is. The Steeda tune helps a lot. Very good tune, but for me, I must SC it to get the torque I need to really enjoy the car. I think Ford did the GT350 intake and cai to try and have "stuff" to make the car different. It really is a GT with less low end torque and HP.

I personally believe the tune from Ford is the major difference.

Which also tells us that the GT engine can take some RPMs. Probably 8K on a semi-regular basis if tuned correctly.

 

[cib24]

How much mid range torque does the GT350 IM really lose out on the 18 IM anyway? From the dyno charts I have seen it's like a maximum of 10 horespower in the mid range. Surely not something anyone would feel?

In any case, those tests are literally just swapping the manifold, not also swapping the throttle body and intake. Or are they?

 

[Schwerin]

How much mid range torque does the GT350 IM really lose out on the 18 IM anyway? From the dyno charts I have seen it's like a maximum of 10 horespower in the mid range. Surely not something anyone would feel?

In any case, those tests are literally just swapping the manifold, not also swapping the throttle body and intake. Or are they?

They are using a JLT intake for all of them, which would flow similar to the GT350/Bullitt intake tube, so while it is testing the intakes more evenly, it's not an exact replica of how they perform in the cars, and may give a bump to the 18+ numbers vs the stock GT tube. To do that they would need a 18 GT and BULLITT intake tubes, ECU's and TB's. Unsure about the TB they tested with though.

 

[cib24]

They are using a JLT intake for all of them, which would flow similar to the GT350/Bullitt intake tube, so while it is testing the intakes more evenly, it's not an exact replica of how they perform in the cars, and may give a bump to the 18+ numbers vs the stock GT tube. To do that they would need a 18 GT and BULLITT intake tubes, ECU's and TB's. Unsure about the TB they tested with though.

I see. So basically, they are not comparable and you cannot infer data from the intake manifold dyno shootout tests because they aren't comparing a 100% stock Mustang GT setup to a 100% stock Bullitt setup, especially if in those shootouts they benefit from a JLT and tune for each run.

 

[GreenS550]

What would have been cool and probably too expensive somehow is to have put a shorter gear ratio transmission in the Bullitt along with the current intake/tune setup. Those long gears take some torque to really enjoy...

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