EFI University

[370 LT4]

Hi ! New here to this forum. Been Tuning my 93 LT4 corvette for 2 years myself and am learning really fast. Came across this forum and it appears to be full of info and knowledge so I'm here to help share and learn.

My setup was a 388 ci LT4 solid roller in a 1993 corvette running a gen 7 dfi with a dual sync. Car ran well and I was learning from scratch and I have come along way. the motor dropped a valve and destroyed everything and is now in the process of being rebuilt.

Few questions I have for you guys :

1. Why isn't there a DFI section in the forums? I know Accel tech support is horrible but its a popular system and one of the oldest around.

2. I want to run a MSD crank trigger setup for timing. Is it easy to setup and/or compatible with the Gen 7 DFI ? I would like to use the Dual sync for a cam signal and the msd crank trigger kit for the crank signal. The motor will see 7500+ rpm so I want to ensure accurate timing.

3. If it's even possible I would like to run coil on plug ignition. If I use the dual sync for cam signal I can use the msd trigger kit for crank I can remove the dizzy cap completely. I know the DUal sync gives a signal to the coil to spark and the rotor pretty much does the sparking so I just cant seem to figure out how a coil on plug would setup would know which coil to fire. I'm wondering if there is a controller or something that can be programmed for a specific firing order and take the gen 7 signal and send it to the coils in the right order.


Besides that I've had tons of seat time in my car playing with the gen 7 and all I can say is I love it. I have the wideband option and it definitely makes things much easier to tune. My 388 ci made 479 rwhp on a Mustang dyno @ 7250 rpm after months of street tuning and learning.

Would appreciate any input.

CHeers, Mike

[Pantera EFI]

I may be of help, I manufacture a 36-1 crankshaft target that can be installed under the front cover of the
SBC when the original cover has the Crank Sensor installed into the front cover, in the stock location.

If the DFI, Accel, Accel GEN-7, Felpro, Fast, Big-Stuff can decode this target,
then you would also need at least four (4) separate ignition channels for "waste-spark" or
eight ignition channels for best performance.

Ask John Meany, he designed the above EMS.

Worst case, I could help with a IGN8-x independent ignition system.

Lance

[370 LT4]

Hi Pantera Thanks for the fast reply !

I'm not sure if you're familiar with the LT1 corvettes but i do know the 96 being the first year with obd2 had a crank sensor in the timing cover. I most easily can pick up one of these. I am guessing your target uses the crank gear mounting points and can be mounted inside the cover? This would be incredible as I wouldn't need to buy the msd kit.

I think first I would just like to get a solid crank trigger setup. Going to a coil on plug ignition setup I will worry about after the car is running. I don't want to change too much and be chasing wiring when trying to get the car fired up.

If you like email me with any more info and prices I'm interested.

thanks!

[TurboCamaro]

What are you using for an intake in order to utilize the Dual Sync in an LT4? As their is no place for a Distributer in the traditional location on an LT engine they utilized the optispark.

Regarding your thought to go to Coil On Plug it is a real easy deal. Meaneys configuration utilizes standard Hall Effect Devices for Cam and Crank Sense, the same as the current generation of LS Engines. Big Stuff is configurable for use with 5 or 12 volt as well as tooth configuration. I will check what the Gen VII uses. For Cam Sense you can use the Cam Sense (Distributer) from a GM Pickup, will get you the GM Part Number. Or I have designed a housing to implement a nice aluminum piece for the Cam and then use Pantera's Crank Sense it may have to be reconfigured to a differrent tooth pattern.

Over the last couple of years their have been some ownership and staff changes internal to Accel DFI which is the reason for their support problems. The current gent looking after support is real solid and will get back to you the same day if you email him in the morning as he typically does product development in the afternoon.

I am running Gen VII on a mild Twin Turbo Small Block, 610hp, 785ftlbs @ 4k on the ground that I am currently swithing over to Big Stuff. Only reason for the switch is to learn the Big Stuff system.

[Pantera EFI]

Yes, you are correct, all the OEM SBC items will work.

I am sure that John can do the 36-1 as he does the 58x GM pattern.

PM with your information.

Lance

[370 LT4]

Thanks for the replies !! Sounds like what I'm asking isn't very difficult at all to do it's just making sure I have the right parts for the setup.

59ram I'm using the GM Lt4 manifold. I had it sent out to LT1Intake.com which from what I have heard lately does not do the conversion anymore. I had it done 4 years ago now. I had to weld an fittings to the stock Fuel rails in order for them to clear the large cap Dual sync. Those are incredibly stout numbers you have there !!

Pantera if the Gm cover will work I'll get a hold of one of those and I'm assuming it will use the gm Sensor as well? If I am understanding correctly this 36-1 wheel will mount in the cover or on the Crank gear and provide points for the sensor to pick up? And this will provide me with a crank signal that I can replace the Dual sync signal with ?

[TurboNova]

What you will need for the Gen 7 is the Accel LS1 decoder to use coil on plug, it will read the LS1 trigger only, I believe though. It changes the LS1 trigger pattern to a 4x signal which you may be able to do so without the LS1 pattern and just use the 4x MSD trigger only, along with the cam sync.
_________________
Brian Macy
EFI University Instructor
Horsepower Connection
www.horsepowerconnection.com

[cutlassefi]

Not sure why Accel doesn't have it's own category, I'm with you I think it's one of the best systems out there, especially for the money. Plus no one I've seen has more transient (driveability) fueling tables than them.

Accel now makes a DIS box that will drive eight coils for coil on plug. Best thing is it also boosts the output of EACH coil like a digital 6 box. Can be used for Carb or EFI applications. Pretty much plugs right in to the Gen 7. I believe they are ready for shipping as we speak.

Have you called Holley or some of the others lately? I know it's kind of a backhanded compliment but unfortunately other than this forum and a few others there isn't much good info out there. It's a shame, that's why people stay away from EFI.

I'm making a "How-To" DVD for Accel, when it's done I'll let you know.
_________________
72 Cutlass Supreme Convertible with an Accel Gen 7 Multiport Sequential EFI system. Accel Dealer since '04. Host of Accel "How-to" DVD.

[370 LT4]

thanks again to everyone who responded. I did finally get a hold of DFI tech support.

Here's what I was considering. Using a crank trigger and the wheel Pantera produces for the crank signal and using the optispark for the cam sync signal. Turns out the one person who I know uses the opti actually uses it for a crank signal. I'm not sure how it works but I do know it has a wheel with 360 points so it can be very accurate. I don't know as of yet if the signal the gm opti pickup outputs will be compatible with the gen 7.

SO I spoke to DFI tech and they told me to stay from anything optical. From what I could understand as long as the crank trigger is there the cam sync does not require a super accurate signal. He also said the DIS box (which I considered but my old shoppe said it wouldn't work- don't know why I listened they seem to still be in carb world) will work perfectly but depends on how my setup is wired. He said there is a white wire which I'm assuming is an out put on when to fire the coil I have now will input to the DIS box and from there it will do the work. I am going to be running an LS1 firing order so I'm hoping theres options there in the box that allow it to change which order to fire the coils.

SO I seem to have a direction I'd like to go in.

1. Use dual sync as cam signal (since I already have it)
2. Use a crank trigger kit ( Pantera )
3. Use a DIS coil on plug controller for ignition.

ALl this will ensure I have accurate timing and even better ignition especially at 8000 rpms.

[TurboCamaro]

Sounds like you have the combination sorted out.

I just wanted to comment on one thing, in that Cam Signal is important! It defines TDC, John's algorithm typically watches for the Cam Falling (or Rising edge) then the next Crank edge defines TDC so a solid Cam Signal is critical.

[370 LT4]

I may have misunderstood. I did speak to DFi for quite some time as I had so many questions to ask him. I can say I got a strong impression that the dual sync will do an accurate, or i should say more than adequate job of providing cam sync.

[cutlassefi]

It will. Remember the inject timing is adjustable so it really doesn't make that big of a difference. Just set it where you have the highest vacuum, greatest amount of O2 correction, and/or the least amount of transient fueling needed.

Sounds like you have a plan and a good one at that.

By the way the Accel part number for the DIS box is 75610. If you want to use an LS1 box, it's a 77657M. Keep us posted.
_________________
72 Cutlass Supreme Convertible with an Accel Gen 7 Multiport Sequential EFI system. Accel Dealer since '04. Host of Accel "How-to" DVD.

[370 LT4]

I most definitely will keep everyone posted ! I would add some pics but I tried to keep the stock LT1 engine bay 'stock' looking with just the distributor in the manifold raising eyebrows. So there really isn't much to look at unless you guys insist of course

SO for now I need to speak to Pantera and see if the setup he has will work for me and fit under a stock GM cover with a billet double roller. I would have expected it be more difficult but if everything works as planned I'll most likely go ahead and do all the wiring before the motor even gets finished with confidence. I will make sure at least if I do mis-wire anything that I can hook up the dual sync as originally was just to get the motor fired and then trace my connections from there.

It's a great feeling when you get responses from a post just wanted to say thanks again and I'll definitely be sticking around this forum and contributing where I can.

[Pantera EFI]

Yes, the SBC 36-1 target has been used on SBC engines with
"dual roller" timing sets.

This uses the stock front cover and sensor for the SBC, late model EFI.

A BBC 36-1 target is also available, can be used with Gen 5 & 6 stock front covers,
same sensor (stock OEM).

Lance