Advice: Sequential distributor?

[Nvrenuf]

So I am in the middle of yanking my Accel Gen VI DFI. Replacing it with FAST. Hadn't really thought about it,but I'm at that point that I should decide. Should I go with a FAST sequential distributor for $350 or whatever? Or should I just "lock up" my MSD distributor and save the cash? (i'm turbo'd and doing this to be able to retard timing under boost) From what I understand, sequential really just gives me a lil better efficiency up to about 1500 RPM. Any thoughts or suggestions? Thanks!

[ProdigyCustoms]

The FAST distributor will make it true plug and play, and sequential. All good things.

[thedugan]

Whats the reason to yank the Accel setup?

[Nvrenuf]

It's an Accel Gen 6 (VI). It just old and antiquated and doesn't do what I want it to. (I have no idea why it was put in the car!) Most importantly, it does not have the control to retard timing under boost. The new Accel versions are much better, but I just decided to go with FAST for many reasons. Mostly "my tuner" is well versed in FAST and that's the most important part.

[XcYZ]

...should I just "lock up" my MSD distributor and save the cash?

I'm no expert on this, and maybe someone else can comment on this, but I believe you need to have a dual sync distributor to run sequential?

[Blown353]

If you want to run bank to bank injection (and it works fine), then your MSD distributor is fine. However you really should rephase the reluctor to rotor relationship such that the FAST receives the signal from the falling edge of the pickup at a crank lead angle of 55-60 degrees BTDC (ideal for a FAST) but then you want the rotor pointing directly at the cap terminals at the timing required at your peak torque/cylinder pressure to reduce the chances of a misfire. MSD sells the adjustable reluctor wheels.

The FAST distributor already has the reluctor to rotor relationship set internally at a 50 BTDC crank lead, and also has a 1x per rev cam sensor output so you can run sequential. The Accel Dual-Sync distributor is the same sort of thing however it has an adjustable rotor so you can easily alter the rotor phasing, however it requires a little bit of re-wiring & connector swapping to work with a FAST.

You can run sequential with an MSD distributor and a FAST, however it requires a crank trigger also. You clip all but 1 paddle on the reluctor wheel in the distributor so it serves as a cam sensor, and the crank trigger does the rest. This is more accurate than having the distributor signal everything as you don't have to deal with distributor gear lash, cam twist, timing chain slop, etc all bouncing the distributor around and leading to inaccuracies in the signal to the EFI box.

[Nvrenuf]

Thanks for the valuable info. I am reading it over and over, letting it all sink in. It sounds like, due to my limited experience... If I just pay for the FAST distributor, everything is done for me. I know I could accomplish the same with my MSD, but whether I do it totally correctly is the question. I will study, but at this point Im leaning towards FAST dist.

[slammed con]

run sequential and buy yhr distributor make life so easy:thumbsup:

[vipercuda]

So I am in the middle of yanking my Accel Gen VI DFI. Replacing it with FAST. Hadn't really thought about it,but I'm at that point that I should decide. Should I go with a FAST sequential distributor for $350 or whatever? Or should I just "lock up" my MSD distributor and save the cash? (i'm turbo'd and doing this to be able to retard timing under boost) From what I understand, sequential really just gives me a lil better efficiency up to about 1500 RPM. Any thoughts or suggestions? Thanks!

If Bob says do it, take his advice do it..... He will not steer you wrong... I get a ride once it is completed...

Happy Holidays
Mike

[Nvrenuf]

Hey Mike! Believe me, I do whatever Bob says. But on this one, he has said it's a toss up and its just up to me. What an awesome guy he is though! Merry Christmas to you also.

[deuce_454]

why not replace the fuel and ignition system all together... ive done a couple of tec3 installs (which is what tom nelson puts on everything, including get 3&4 engines) and ive helped tune an xfi.. (which ill install next time... seems way better than tec3)...

but monkeying arround doung half solutions doesnt seem right, especially on a turbo car....

[vipercuda]

Hey Mike! Believe me, I do whatever Bob says. But on this one, he has said it's a toss up and its just up to me. What an awesome guy he is though! Merry Christmas to you also.

I can tell you we go sequential on all. I have done both with Bob and we like the sequential deals better...

I still want a ride in it....

Merry X-mas,
Mike

[Blown353]

why not replace the fuel and ignition system all together... ive done a couple of tec3 installs (which is what tom nelson puts on everything, including get 3&4 engines) and ive helped tune an xfi.. (which ill install next time... seems way better than tec3)...

but monkeying arround doung half solutions doesnt seem right, especially on a turbo car....

I also prefer the software interface of the FAST/XFI to the Tec3... however the edge in overall system accuracy of injection & spark events falls to the Tec3 because of not only their 58X wheel but also how they watch the wheel velocity & acceleration. I just chassis dyno tuned another Tec3 on Tuesday actually. The software is a bit more cryptic and "clunky" than FAST but it's a very good system... honestly I give the hardware advantage to the Tec3. Their latest WinTEC software is FAR better than earlier releases but still not as user friendly as the FAST especially when it comes to on the fly table changes, the FAST allows block cell selection/addition/subtraction/multiplication whereas the WinTEC software limits you to single cell changes when tuning on the fly. The FAST cell selection scheme is a HUGE time saver!

A FAST triggered by a distributor gets only 4 pulses per crank revolution and thus during rapid engine RPM changes can output substantially different injector & spark timing events than commanded especially if the engine experiences a rapid acceleration change between trigger events since it's only updating the engine RPM 4 times per crank revolution. This leads to timing/injection "lag" under rapid engine acceleration, and timing/injection "overrun" during rapid deceleration.

With a Tec3 and the 58X wheel it watches both rising edge, plateau, and falling edge of the teeth so it's seeing 174X separate events per crank rotation and thus has much more accurate timing & injection control because the instantaneous acceleration & velocity of the crankshaft is known with far more precision. That's also why GM is using the 58X scheme on the latest LS engines, much more accurate control of timing & injection events because the ECU can decode exactly what the crankshaft is doing with far more resolution & precision. Same goes for the Pantera 882... which is what I'm using on my new twin turbo LS2.

Another option... buy a a FAST XFI with an LS1 harness. Fit a 58X wheel onto your Gen 1 SBC and make a crank sensor bracket. Then use that instead of the distributor. That would be the most accurate way to trigger the XFI.

[deuce_454]

^ nice to hear... i still have my tec 3 in the 32..
but in all honesty the tec isnt that bad to tune, if you get it right in the wizard it is only a matter of finetuning... its just a matter of understanding what minimum pwit does for idle and all the other "not intutively logical" results of changing a digit...

i really like the GPO´s and second fuelpump option.. and for a turbo car the aux injector option is really cool...

so once again... change the accel 6 to somthing usefull :D

[Pantera EFI]

One method, the one I use, is an Oil Pump Drive with a
48-2 target inside.

The apperance of the distributor is retained, though the cap is missing in some cases.

When this item is fitted, sequential coil (8) AND injectors (8) are controlled by only ONE hall sensor inside the OPD.

The "Gear-Down" 48-2 target would be the same as 24-1
ON THE CRANK.

Yes, we measure the tooth accelaration which allows for a more accurate "spark instant".

Lance