Optispark vs HEI
Thread Starter
Racer
Joined: Aug 2002
Posts: 305
Likes: 0
From: Mo
Originally Posted by Greg Gore
Melting Slicks
Joined: Nov 2006
Posts: 3,418
Likes: 1
From: Where CUPCAYKE lives Ontario
I just bought a 92 LT1 (see avatar) and while made aware of the Opti isssues, i didn't realize that I couldn't powerwash my engine...just some road dust to remove before I park for the winter..
Any suggestions on how I can clean it up?
Thanks. Lauri
Any suggestions on how I can clean it up?
Thanks. Lauri
Le Mans Master
Joined: Feb 1999
Posts: 6,470
Likes: 2
From: levittown pa. usa Even a bad day with my `Vette, is better than a good day at work
St. Jude Donor '10
Originally Posted by Greg Gore
It gets into a discussion concerning engineering...square wave output versus sine wave and the advantages of one over the other. 97 went back to a sine wave with hysteresis correction programmed in the computer. The Opti is based upon a sound principle and can do things DIS cannot but the engineers screwed up by not realizing C4 owners might hose their engines down so it went away after it generated some warranty costs. In other words we owners taught GM that they will have to build stuff more bullet proof than that.
The Opti also solves these issues which affected timing accuracy:
1) Torsional twist in the cam core.
2) Backlash that would be present in the distributor/ cam gears.
3) Distributor shaft end play between the housing and the gear thrust surfaces which translates to advance-retard movement due to gear helix.
4) Camshaft distributor drive gear runout; gears are never hobbed to concentricity on the cam cores and the norm is .002 - .004 runout.
5) Aluminum distributor housing sensitivity to heat and length change. Helical gear advances timing as distributor housing is heated.
6) Wear in the distributor gears or shaft bushings
In addition if you throw or break a belt you do not overheat due to the water pump being direct drive. Direct drive also eliminates lateral belt loading on the water pump bearings.
The Opti also solves these issues which affected timing accuracy:
1) Torsional twist in the cam core.
2) Backlash that would be present in the distributor/ cam gears.
3) Distributor shaft end play between the housing and the gear thrust surfaces which translates to advance-retard movement due to gear helix.
4) Camshaft distributor drive gear runout; gears are never hobbed to concentricity on the cam cores and the norm is .002 - .004 runout.
5) Aluminum distributor housing sensitivity to heat and length change. Helical gear advances timing as distributor housing is heated.
6) Wear in the distributor gears or shaft bushings
In addition if you throw or break a belt you do not overheat due to the water pump being direct drive. Direct drive also eliminates lateral belt loading on the water pump bearings.
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Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
Originally Posted by kenv
Thats all cool but, I`m wondering if the genius who said " Let`s mount the opti right under the water pump" still works for GM
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
Originally Posted by WYCKD14U
I just bought a 92 LT1 (see avatar) and while made aware of the Opti isssues, i didn't realize that I couldn't powerwash my engine...just some road dust to remove before I park for the winter..
Any suggestions on how I can clean it up?
Thanks. Lauri
Any suggestions on how I can clean it up?
Thanks. Lauri
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
Originally Posted by oldtimer
He'll probably smack his kid for using the Fword !!
Le Mans Master
Joined: Dec 2004
Posts: 7,475
Likes: 2
From: Austin TX
St. Jude Donor '07
Originally Posted by kopbet89c4
Hell, my buddy's 93 3.3L V6 Grand Am was more high tech than the LT1. Although a lot slower, it had a DIS. It has over 200k miles on it! Still running good today. GM didn't use that feature on their beloved V8s till 97 with the LS1. WTF!!! What a way to go...
I might not be the smartest tool in the shed as well as the CF bandaid bandit ghetto rigger, but I CERTAINLY know that LT1s ain't no super motor either!
Now flame me for being such a drunkazz...
I might not be the smartest tool in the shed as well as the CF bandaid bandit ghetto rigger, but I CERTAINLY know that LT1s ain't no super motor either!
Now flame me for being such a drunkazz...
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
Originally Posted by VetteUSA
Ummm, the ZR1's had a DIS.
Le Mans Master
Joined: Dec 2004
Posts: 7,475
Likes: 2
From: Austin TX
St. Jude Donor '07
Originally Posted by Greg Gore
DIS has a sine wave output and Opti has a square wave. Square wave can do things a sine cannot without hysteresis correction.
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
Where on the slope of the sine should the computer recognize data input? Square wave doesn't have that problem, very high resolution. It was admittedly overkill as was reverse cooling and both quietly went away with LS-1. It is interesting to note square wave technology is still a player today with Crane Cams new Chevy race distributor which includes hype in the advertising.
