I'm considering the Pete Jackson "quiet" gear-drive while I have the top half of my engine apart. Any truth to the old rumor that gear drives rob HP? If so, how many HP could I expect to lose? Thanks in advance.

 

i believe they do, but that doesn't mean much. if you have a roller engine the gear drive won't work anyway.

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ICON Motorsports

1st & 3rd

 

The gear drive will work as long as you are not using a knock sensor.....IE carb. The knock sensor picks up the gear drive as detonation. That's the only reason they won't work.

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

2001 Dodge Ram Quad Cab 5.9L 4*2

ASE Certified Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

Willie and I have the 'quiet' drive and dont have false knock problems.

It will probably rob you of a few HP over a double roller timing chain. Thats why you see belt drive setups, those are supposed to be the best setup of all of them.

 

Initially, I suppose it is possible that a gear drive setup will rob a little power(very little). That is more than made up once you get a few miles on the chain set-up and it stretchs a little--causing inaccurate cam and ignition timing. The gear drive will remain accurate a lot longer. If I had the engine apart, and had a little extra money, I would install the gear drive.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

 

I have been running the Pete Jackson on my '89 formula 350 Computerized... Fuel Injected... Roller cam motor.

Not one problem or one false knock yet... And I have been running one for almost 4 years now on the Firebird.

The noisey ones can creat false knocks, but don't believe the myth that the quiet ones do. Listen to the people that have them and run them daily, not the ones that say their bothers cousin second uncles step sons friend said that his knocked.

And yes, you can get a quiet gear drive for a roller cam.

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Sportsman II 72 CC heads, Pete Jackson gear drive, Performance Resources chip, Edelbrock 1 5/8" headers and Edelbrock cat back exhaust, hi-flow cats, Trans-go stage 3 shift kit, Vigilante 9.5" 2800 stall convertor, SLP cold air induction, SLP roller camshaft, 24lb ADS injectors, AFPR, 3.45 rear end gears, and other goodies...


raven

 

the geardrive will cost a little horsepower but no more than 2% max. They transfer a LOT of vibration from the crank into the valvetrain, so I do not recommend them.

The one guy is right, the beltdrive is by far the best way to go, though it's way more expensive than a chain setup.

If you insist on the geardrive and suspect the knock sensor problem then simply unhook the sensor and run without it.

good luck


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*I do custom performance mods on Edlebrock Performer carburetors (dualplane intake mods in the works),
White 1986 Irocz, 305/383 with Edlebrock Performer-RPM intake and Performer #1407 carburetor, +110hp shot of crack, 700R-4 tranny, 3.25:1 rear, Mcreary Road-Stars, SLP-stainless 1.75" shortie headers & Y-pipe, single 3" Borla exhaust, Linginfelter-TPI camshaft part number 74216 pulls 17" vacuum solid. Cam specs 213/219 @.050 114-LSA, .462/.470 lift @1.5:1 ratio. MSD-6AL, billet distributor, multi-retard, blaster-3 coil, and RPM switch.
N/A runs 10.9 @124,
Crack-runs 10.3 @135
haven't run at track since Oct-99

[This message has been edited by The ODB (edited February 05, 2001).]

 

Since Madmax and Willie both have "quiet" gear drives and scan tools, they have been monitoring the knock incidences; especially Madmax as he is also into eprom burning. So I can accept their personal testimonial on the quiet gear drives.

I should add that if it did introduce a little knock indication, I would not recommend disconnecting the knock sensor or attempting to physically "desensitize" it. I would suggest attacking the problem directly in the eprom by reducing the knock sensors "attack rate" and increasing the knock sensor's "decay rate".

I have been playing quite a bit with the Spark Tables on my car and I have a persistent "inaudible" knock that seems to occur during a shift. I have researched this and it appears automatics are prone to this with locking convertors. I found the decreasing the "attack rate" (limits the speed at which the knock sensor adds spark retard) and increasing the "decay rate" (the speed at which the knock retard is removed) greatly helped in dealing with this "inaudible" knock while still retaining the safety feature of the knock sensor.

Further, I have been increasing my spark advance and I have not turn "inaudible" knock into "audible" knock; which is the one that kills. The only time I encountered any "audible" knock was when I leaned my VE tables a bit too much on the WOT load setting; and my Spark tables were very conservative and my "attack" rate and "decay" rate were still at the stock setting.

FYI, playing with the Spark Tables and the Knock "attack and decay" rates has resulted in some definite performance gains.