Just pondering running aftermarket EFI on my Vega next year and wondering how does the system control timing?

 

Both of these systems control timing by using a GM or simular type of distributor that allows for electronic timing control. If you are drag racing only then a FAST system is adequate, if you plan to use your Vega as a street car then the Accel Gen 7 system is the way to go as it offers far better tuning and drivability than the FAST system. If you want a GEN 7 system be sure to contact me, I know a dealer that will beat anyones advertised pricing.

 

Fast is adequate??????

I think you have not seen a street car with F.A.S.T.. I have one that runs 6.80's at 102 on nitrous. It is a street car with air. F.A.S.T. is just as good as gen 7 and I hear it is more user friendly to tune with.

As far as timing the way to go is a points output MSD with the system. Set advance and retard with the fast at 300 to 400 rpm splits.

 

Yes it will work, but with a G7 you can get much better drivability with it than a FAST any day. Especially on engines with long duration cams. Even the old Gen 6 stuff still works great in drag racing applications, and the G7 stuff is every bit as easy to tune as the old FAST stuff but it has more functions to dial in a daily driver than FAST does. Plus the G7 stuff comes with everything in the firmware, you want something different in a FAST then you have to send it for a firmware upgrade in or pay for it up front when you buy it. If you want a sequential fire just change it in the configuration in the G7 setup and buy a dual sync distributor, want a wide band, change it in software and add the hardware, to do either of these in FAST you pay extra and if you have one that don't have it presently you have to send it in and pay even more.

Take that 6.80 street car up to 7500 feet and see how it runs. I've used FAST in several 502 suburban conversions, tune it for one altitude, and you are fine as long as you don't go somewhere where its drastically higher or lower. Now I just use the OE PCMs for the conversions, not a bit of a problem with them.

The G7 is as near as OE quality as you can get, the G7 fuel strategies are as far advanced to the FAST as the FAST is over the old G6 systems or more. Just my two bits, its all about personal preference and budgets.

 

Two questions,
1. how does the computer control the timing?

2. Anyone know where I can get a conventional SBC intake that has been drilled for injectors? and What about TB's? Where to get one of those?

BTW this Vega is a strip only car.
Thanks

 

You can get a EFI manifold already made up for EFI from Accel. Just go to their website and you can see what they offer. Also there are several companies that will take a Edelbrock Victor Jr or similar single plane and convert it to MPFI for you. These conversions costs around $300 to $450 depending on the depth of modifications that you would want. As for throttle bodies, once again check out Accels website for their TBs. They have sizes ranging from 1000 CFM all the way to over 2500 CFM

As for how the ECU controls timing, it is all done electronicly via the ECUs timing maps which sends a EST (Electronic Spark Timing) signal to the distributors control module. Normally to set the timing for instance in a Accel Gen 7 system, you can force the timing to X degrees, then with a timing light you set the timing to this timing value and lock the distributor down. After than the timing is done totally within the ECUs timing maps which are based on engine speed and MAP (Manifold Pressure) Sensor signal. In the old days we had to set the whole timing map to a given value then set the distributor but now with new software tools things are a lot easier.

All these systems, FAST, Accel, Electromotive and others all use standard GM sensors and ignition parts. Accel can now also use the Ford TFI ignition systems or they can fire an aftermarket MSD, Crane or similar ignition.

In a typical GM scenario the old HEI manual ignition had a 4 wire module, of these four wires, two are from the distributor pick up coil the other is power an the last fires the coil. Advance is all done mechanically with weights and a vacuum can for the vacuum advance. Later when electronic controls were introduced in 1980, the original C3 system which stands for Computer Command Control (how many of you even know about that one?). That was the start of the electronic spark timing controls and the 7 wire module was introduced. Added to the circuitry as the EST, reference, bypass and a redundant ground circuit. From then on the rest is history, with each passing year engine and fuel strategy complexity advance exponentially. Starting in model year 2005 the standard ALDL link with its antiquated serial bus will begin to be phased out for a new communications protocol called CAN which stands for Controller Area Network. With the advance of in car sensors and smart devices. There was a need for this new protocol for which all these devices can communicate on one bus.

In industrial applications we have been doing this for years in distributive controls systems and PLC networks. To me its funny that the morons in the Automotive Engineering fields have finally started to use similar networking buses to eliminate the mulitude of wiring harnesses within a typical automobiles of today. Sorry for the ranting, so now I hope you know how it works .....

 

The car would run just fine ...remember I have F.A.S.T. and a wb 02.

 

Ahh but the Gen 7 will perform at altitude even better with built in barometric compensation And if your maps are out of range of the FAST ECU correction limits it can't compensate much. I still have a FAST system on the shelf with the wide band option if you know anyone interested. Its used but in perfect condition. It came out of one my 502 suburban installations.