Optiless LT1(Picture)
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Pro
Joined: Aug 2009
Posts: 725
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From: Plano, TX
Optiless LT1(Picture)
Yes the LT1 is very similar to a small block chevy. In fact the LT1 aftermarket cams come with a distributor drive gear. Its just a matter of drilling the hole in the intake in the right place. The distributor is an Accel dual sync with crank and cam signals. The aftermarket computer is an accel gen 7 dfi. It runs fully sequential injection. I piggyback the the stock computer which runs some basic functions like Air conditioning clutch control and Dual Fans turn on. The opti is still on the car but it is only used for its high resolution signal to the stock computer so that it thinks the car is running under the stock computer. All the engine control, fuel injection, ignition, and IAC is controlled by the Gen 7 computer.
The car runs like a raped ape. 383 with AFR195 heads, CC503 Cam. Idles and drives like stock. There are no check engine lights and the computer is hidden under the dash. It gives me the ultimate in tuning abilities with Wideband fuel control for perfect Air/Fuel ratio at all engine speeds.
The car runs like a raped ape. 383 with AFR195 heads, CC503 Cam. Idles and drives like stock. There are no check engine lights and the computer is hidden under the dash. It gives me the ultimate in tuning abilities with Wideband fuel control for perfect Air/Fuel ratio at all engine speeds.
Last edited by 93VettePilot; Sep 16, 2012 at 06:14 PM.
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Melting Slicks
Joined: Jul 1999
Posts: 2,875
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From: Olive Branch (Memphis suburb) MS
Cruise-In II Veteran
Nice setup. I'm runnng the DFI 7 also. I still use the opti (no rotor) to signal the DFI and the stock computer so the gauges function correctly. I like how your running fully sequential. 
Racer
Joined: Dec 2009
Posts: 317
Likes: 8
From: Houston TX
How did you piggy back the systems? I have a similar setup: Running a Holley SR on a LT1 engine in my TPI 90. Thinking of using a Holley C950 FI system, but maybe the TPI computer with chip might just work? The Holley SR has long runners similar to the TPI but obviously larger. I used to have a Accel Big mouth intake, runners, ported Plenum and 58mm TB.
Thread Starter
Pro
Joined: Aug 2009
Posts: 725
Likes: 4
From: Plano, TX
How did you piggy back the systems? I have a similar setup: Running a Holley SR on a LT1 engine in my TPI 90. Thinking of using a Holley C950 FI system, but maybe the TPI computer with chip might just work? The Holley SR has long runners similar to the TPI but obviously larger. I used to have a Accel Big mouth intake, runners, ported Plenum and 58mm TB.
As far as piggybacking, basically you leave most of the stock computer/vehicle wiring alone. You run the accel wiring to the fuel injectors, IAC, Map, Ignition box, coil, and distributor. Alot of this wiring can simply be spliced into the stock harness next to stock computer. My car came with a "Fasttrack"(Now called horsepower connection) harness that had good directions on which wires go where. It takes time to do it right. I soldered in all the wiring and shrink wrapped it to make sure that no water or vibration would cause problems.
Last edited by 93VettePilot; Jun 30, 2011 at 01:36 PM.
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
I removed my stock computer entirely. All guages and speedo function 100%
Only reason I went this route was because im spinning past 8000 rpm. Nowadays i wouldnt even reccomend it i would say go LS route with coil on plug and efi connections setup. How many well known dfi tuners are there? i cant name any. with efi connections setup you eliminate the opti COMPLETELY and it uses an ltx billet timing cover with reluctor wheels for the signal. There are capable tuners for the ls computer anywhere and everywhere in the world.
Hard to believe its been almost 10 years since i did the dfi swap back then it was cool
Only reason I went this route was because im spinning past 8000 rpm. Nowadays i wouldnt even reccomend it i would say go LS route with coil on plug and efi connections setup. How many well known dfi tuners are there? i cant name any. with efi connections setup you eliminate the opti COMPLETELY and it uses an ltx billet timing cover with reluctor wheels for the signal. There are capable tuners for the ls computer anywhere and everywhere in the world.
Hard to believe its been almost 10 years since i did the dfi swap back then it was cool
Last edited by 5abivt; Jun 30, 2011 at 01:50 PM.
Thread Starter
Pro
Joined: Aug 2009
Posts: 725
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From: Plano, TX
Its STILL cool. LOL The coil on plug(LS1) never had the visual appeal of an old school distributor for me. There are many other choices as far as aftermarket computers go. Accel, FAST, Bigstuff3, Holley, LS1 computers. I would think that if a tuner was very reputable then he would know how to tune on all of these.
Last edited by 93VettePilot; Jun 30, 2011 at 05:34 PM.
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
Its STILL cool. LOL The coil on plug(LS1) never had the visual appeal of an old school distributor for me. There are many other choices as far as aftermarket computers go. Accel, FAST, Bigstuff3, Holley, LS1 computers. I would think that if a tuner was very reputable then he would know how to tune on all of these.
Now theres so much out there. I agree someone can tune most of those but tuning an LS can be done almost anywhere and there are probably hundreds of reputable tuners. The ls ecm is awesome. The coil on plug doesnt look as good but the efi connection setup is just badass for the price. With my first motor grenaded I am still contemplating on how I can get a crank signal without having both signals off the dual sync. In the end I may just put a magnet trigger setup behind the ati pulley for an accurate crank pickup and let the dual sync do the cam sync. I will say that getting to learn the DFI is kick butt. Ive tried a few other systems for friends and they dont have nearly the tuning options the dfi gives you.
Here's a before pic I usually post up on here because its the most hideous shot I have of the car
Here's how it looked not long after we got it running. it will look a little different with the new motor as I removed the a/c etc as well. Blowing up an ac compressor and watching it catch fire on the side of the highway after an 8000 rpm blast was exciting !
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
Here's a post by efi that did the conversion. To me this is the best route possible. After I get my motor up and running I will remove the dfi and go this route and have someone very experienced dial my motor in. I'm leaving the dfi in for now to eliminate possible issues to get the car up and running. I learne my lesson changing too many things at once and then trying to toubleshoot :/
http://ls1tech.com/forums/parts-clas...onversion.html
http://ls1tech.com/forums/parts-clas...onversion.html
