LOL

"Jake - Has Bad Luck So You Don't Have To" (murdersofa) 07/31/2017 at 12:32 • Filed to: None

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Yeah, okay Jag. “The car everyone dreams of. But very, very few can ever own.” holy crap I’m dying. Kinda wondering how a 280hp engine hauls 4000lbs to 60 in under 7 seconds. That’s impressive. Mine certainly does not do that. Maybe 7.5 seconds. Maybe. And I’m gear-limited to 125mph at the moment. Ugh.

Later this week: removing the fuel tank to chase down a fuel smell in the trunk, removing the seats, removing the floors, and welding in the new ones. Possibly also aligning the doors. Once all that is done the Jag should be far closer to the original “level of silence.. that will astonish and delight you” instead of the current “rock concert in the middle of a hurricane” situation from the 1/2" gap at the bottom of the doors and the big holes in the floor.

crowmolly > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 12:41

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Kinda wondering how a 280hp engine hauls 4000lbs to 60 in under 7 seconds.

Rear axle ratio?

I know the late 70's Z28s had ~185 hp and could do it in 7.5 @ 3600.

Jake - Has Bad Luck So You Don't Have To > crowmolly 07/31/2017 at 12:42

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I suppose, but then how does it get to 150mph with a 3 speed auto? Like I said. I’m gear-limited to 120-125 because I hit valve float around 5300rpm.

RamblinRover Luxury-Yacht > crowmolly 07/31/2017 at 12:43

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XJS V12 rear axle ratio is 2.88:1. I know the sixes are lower, but how much I don’t recall.

Edit: to amend that, I believe Euro XJS had an option of a lower rear, but the US market one was 2.88 only for the V12.

Smallbear wants a modern Syclone, local Maple Leafs spammer > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 12:45

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That’s not far off. I’ve got 300hp and ~4250lbs, around 7 second 0-60.

RamblinRover Luxury-Yacht > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 13:02

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Low first, and a torque converter the size of a tire. Rear axle ratio is quite high, and you just need a flat enough torque curve to patch the space between gears.

Even my Galaxie (which has a three-speed) has no complaints being in 2nd from 0 all the way to 50mph+ *fast* out of a Windsor small-block - torque converters are amazing when they have torque delivered to them.

Jake - Has Bad Luck So You Don't Have To > RamblinRover Luxury-Yacht 07/31/2017 at 13:06

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Hmm. I’ll have to do the math and see what my 3rd gear final drive ratio is like. I know my car was a V12 car originally and I doubt someone went to the effort of swapping out the rear end.

LongbowMkII > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 13:11

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Torque.

Jake - Has Bad Luck So You Don't Have To > LongbowMkII 07/31/2017 at 13:27

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TWERK. 300 lb-ft on a 5.3 V12.

MultiplaOrgasms > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 13:33

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So yeah the early ones were the lightest and thus fastest, especially with the 5-speed manual. Every XJS that came after was heavier and mostly automatic. That didn’t however stop them from pulling hard once you got them up to revs. I’ve been digging MotorWeek Retro Reviews lately, their ‘86 3-speed XJS accelerated to 60 in a mind blowing 8.5s and managed a 16s 1/4 mile, but with a trap speed of 95mph.

Jake - Has Bad Luck So You Don't Have To > MultiplaOrgasms 07/31/2017 at 13:35

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Yeah the High-efficiency 5.3 was kinda crap. The 6.0 made up for most of it.

MultiplaOrgasms > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 13:36

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Even the 6.0 was slower than the pre-HE 5.3

RamblinRover Luxury-Yacht > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 13:44

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Could be that the V12 hits a torque peak earlier than the Chebby, and that the gears are kind of tall for what the Chebby can do when it does it. I would assume 3rd is drive, aka 1:1, so you should be at ~4400RPM if your tires are something like a 215/70R15 and you have those 2.88 gears.

My X-type is too a real Jaguar > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 14:22

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Jake - Has Bad Luck So You Don't Have To > My X-type is too a real Jaguar 07/31/2017 at 14:31

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You are BULLSHITTING ME if that’s a real ad.

My X-type is too a real Jaguar > Jake - Has Bad Luck So You Don't Have To 07/31/2017 at 14:42

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There was a Movie in the 80s called Crazy People, Starring Dudley Moore, about an ad exec who went crazy and decided to make ads that spoke the truth. Through Hollywood comedy of errors the ads got published blah blah blah and that was one of them.