Intake boot collapse - video

[Wwabbit]

Great video!

I while you are at it I would check the condition of your air filters.

.... It would hurt to call Rich and Dennis to get their upgraded intake system too… it’s ****ton better than the stock setup.

...... points to additional restrictions that you will want to look into.

All great points. Thanks for those. When I saw the degree to which this happens at just moderate go-get'em power, l thought about the filters. I should note that these symptoms were there from the very first drive when I bought the car at 200 miles on the clock and with the 2.9" pulley. That's the only known change to the car. I'd be surprised to find dirty filters (maybe a mouse nest since the car has obviously sat a lot). But you can bet I'll be digging into the air box further and will report back. My guess right now is, it's just the wimpy Ford boot, but the stock air box is likely a bit restrictive for the high air flows we now seem to like. FYI- I'm planning a 2.7" pulley change with an updated tune on a dyno next month.

Things like this can be fun so long as everything stays healthy. I gives something to do.

[shelbyelite]

Call me before you change that pulley

[Triheart7]

I'd love to see a video with the support installed.

[nota4re]

Bored at lunchtime.... Indy or Ice, please correct my calculations....

Our GT engine is a 4-stroke V8
On any given revolution, 2 cylinders are filling (2 are compressing, 2 are on power stroke, 2 are exhausting)
2 cylinders filling = 2/8 = 1/4 of 5.4L = 1.35L of air ingested at each revolution (with no boost at sea level)
With 14.5 psi of boost = 2x the air ingested = 1.35L x 2 = 2.7L air at each revolution (Can I say this....approximately?)
2.7L x 6000 RPM = 16,200 L per minute @ 6,000 RPM
16,200 / 60 = 270L per second @ 6,000 RPM
270L = 9.5 cubic feet of air PER SECOND at 6,000 RPM at 14.5psi

As usual, I'm probably wrong.... but maybe the smarter guys can be quick to correct. My conclusion is that we need a "mega-boatload" of air each second.

[BlackICE]

Kendall you are using the correct logic, but the auto industry calls a stroke only a half rotation of the crankshaft or, a single up or down movement of the piston. So each complete rotation of the crank sucks in 1/2 of 5.4L at one ATM, so an assuming an effective 2 ATMs (ie. 14.7 PSI boost nomalized for density, really the boost is higher due to heating the air) the engine sucks in 5.4L per rev. So at 6000, 6000+5.4=32400L/min. Double your numbers. 19 cf/sec or 1140 cfm

Now just think of the gas velocity through the small openings in the airbox, MAF, and throttle body!

[Fast Freddy]

I had been chasing a hesitation and power loss that occurred reliably in the 4000-5000rpm range on a good dig. I mistakenly assumed it was either plugs or a jiggery fuel pump relay. So I eliminated those ((( by the way, everybody has a couple of spare fuel pump relays - they are otherwise known as the wiper relays and they are stored right beside the fuel pump relays - most owner's wiper relays are virtually new and can be a convenient way to test your existing fuel pump relay))) Back to my story, so this weekend I was changing out my halfshaft bolts and I had the air box off and noticed how floppy the intake boot was. Pretty wimpy. I found myself wondering just how much suction there must be on the intake side at high boost, then the light came on - yep I was running a 2.9" pulley and I recalled the previous posts on the subject. I'm a bit slow on the uptake sometimes I guess.

So I dug out a GoPro and stuck it under the clamshell and, here's what it look's like in case you were wondering.... See you later, gotta call Accufab.

that is a total fail right there

[topshot]

I had to order one today from accufab, that is the best commercial they could have,,,,they should give you yours for free for the publicity..

[BlackICE]

I had to order one today from accufab, that is the best commercial they could have,,,,they should give you yours for free for the publicity..

I don't think they are all that bad. If I had to guess the OEM stiffener is missing. It much smaller than the Accufab one about 1" wide. I found it when I when to install the Accufab part and it wouldn't go in, the OEM part was blocking it.

[MTV8]

Great video. I had wondered the extent of the inlet issue. Are you sure the stock support is there?

I am glad that my carbon fiber inlet is finally on the way after a multiple month wait.

[2112]

I am glad that my carbon fiber inlet is finally on the way after a multiple month wait.

From Whipple?