lightning25

i was reading motor trend magazine about the new shelby 500 with all the added power and such it has and it listed one of the reasons it has more power is due to being able to raise the timing because it has a knock sensor (to help prevent detonation).

i thought and was told our trucks didn't have one due to the blower making too much vibration or something??
so how can these cars with blowers have them then? (newer technology?)

Sean

FASTFORDS

2010 will have knock sensors. The additional power comes from the FRPP intake and tune. I assume the knock sensors are more of a safety item. Like Lightnings and Cobras the GT500 pulls timing based on IAT's. I don't know about vibration as the car seems as smooth as my 04' L did.

throttle jockey

There is a product on the market made by J&S Electronics called the Safeguard Vampire Direct Ignition Individual Cylinder Knock Control System. BgStew06 used his truck for testing starting about a year ago. To this day he runs the system and he swears by it. I'm about to purchase one myself but I'm trying to decide where I want to mount one of the optional gauges before I order it.

J&S Vampire

Lightning Forum | LightningRodder.com

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#4162 of 4270 - BUILT 19 JUNE 2003

99 SVT

Its about time. Most of the cars I've owned had them. Saabs, Porsches etc. Even my Toyotas have them. It would've saved a lot of blocks in our trucks if they had them.

MorpheusGPR

99 camaro had a knock sensor.

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2001 Black Lightning
Build: 5,075 of 6,381
Built: June 15th, 2001
Bought 7/31/01

JohnnyP

Turbo Buicks have had them since '78.

oilwell1415

Actually, it has two of them.

The problem with the knock sensor on the L isn't vibration you can feel, it's the harmonics from the blower. A lot has changed since the L engine was designed over a decade ago.

throttle jockey

If you read the thread I attached in an earlier response you'll see that the Safeguard very effectively uses the knock sensor installed on our trucks by Ford to do its job of retarding timing when knock (silent or audible) is sensed. Apparently harmonics from the blower isn't as much of an issue as it was once thought to be.

JohnnyP

I don't know the reason Ford decided not to use knock control, but if Stew's stock block engine is representative, it wasn't due to harmonics from the blower.

Here is a photo of the sensor activity on his truck at freeway cruise. Ignore the top trace, since that channel is not connected.

The bottom two traces show the "signal" and the threshold.

The signal is essentially a flat line at cruise, indicating no interference from the blower, and no valve clatter or piston slap.

The other trace is the threshold which is applied during the knock window.

To the unaided ear, an inaudible knock would show up as a pulse on the lower trace that would go off the screen, easily crossing the threshold and generating a proportional amount of knock retard for that cylinder.

Attached Images

F150Cruise1.jpg (13.8 KB, 21 views)

oilwell1415

And I'm sure that it works fine in 99% of the applications out there. If it doesn't work in 1% of the applications an OEM isn't going to use. There was probably one test case in some remote realm of the operating envelope that showed problems with the knock sensor and blower combination and that is enough to keep it out of production.

JohnnyP

Apparently Diablo was working on a knock program several years ago. A beta tester posted about it, and said
Complete thread here:

Diablo knock sensor program - F150online Forums

bgstew6

J&S FTW!!