F.A.S.T. Sequential question

[WaterPog]

Hello all,

I am getting pretty close here to dropping my motor in and getting busy with the FAST install finally, but I have been thinking some and had an idea to toss out there. It's about the crank trigger/cam sensor setup for the sequential system.

Basically the crank trigger needs to signal at every spark event, and the cam needs to signal once every other revolution correct? I currently have an MSD inductive pickup distributor for my 5.0L (MSD 8582) and was planning on just picking up the MSD crank trigger setup to go with it and taking off the tangs for everything but cylinder #1 on the distributor so that it will act as a cam sensor. I had another idea though when I was installing the cam.

there is an eccentric on the end of the cam, not sure if it's for balance or what it's really for, but it's ferrous so I was thinking that i could make a provision to mount a hall-effect sensor in the timing cover to read that as my cam signal and use the distributor as the crank sensor.

Any reason this wouldn't work? How long can the cam signal be before the FAST gets confused? Has this been done allready and if so how did it work out?

Thanks in advance guys,

Eric

 

[Craig Smith]

I don't think an eccentric is the best trigger to use for this type of sensor. The strength of the pulse detected by the sensor varies with RPM; the faster the cam spins, the stronger the pulse. With an eccentric, there is also a constantly varying airgap for the sensor, which also effects signal strength. I think the combination of these two variables will make your cam sensor questionable at best.

Hope this helps!

 

[WaterPog]

eccentric may be the wrong word here, it's not a full ring it's maybe 90* of rotation on the cam. Like I said it's almost like it's there for a counterweight or something, i'll see if I can find a picture.

 

[Craig Smith]

As long as the airgap is constant I think it would be OK then. I think I understand what you mean now.

In order to do this you need to be able to have the rising edge of this signal happen somewhere prior to the crank pulse for the #1 cylinder. It just tells the ECU that the next crank pulse is for #1 cylinder.

One other thing to consider is that the FAST unit has hardware inside it configured for either an inductive pickup sensor or a hall-effect sensor. Unless you had ordered it for a hall-effect sensor or have had it converted in the mean time, the unit is currently set up for an inductive sensor.

 

[WaterPog]

I'll probably end up just getting a crank trigger setup, do you have a reccomendation for a good one? I am pretty sure that the MSD wheel is only set up for a 3-bolt pulley but i'll be calling them here soon to verify that. I noticed that Aerospace is selling them now, looks almost identicle to the MSD system and is a bit cheaper.

 

[Racetronix]

The other option is to buy an Accel / Mallory billet e-Sync distributor which has both cam and crank signal outputs on it generated by two hall-effect sensors. Racetronix sells these distributors for Ford SB, BB, & W motors in small and large cap versions. A SB Ford large cap distributor is $299.99. You can send your ECM to FAST in order to have the I/P configured for hall-effect sensors. This will provide very stable timing compared to the MSD IPU version as well as saving you over $100.00.

Jack
Racetronix
www.racetronix.com

 

[WaterPog]

Well, i've allready got an MSD Inductive distributor, so all I really need is the crank trigger setup to complete the set. How much would the conversion to hall-effect run?

 

[Racetronix]

A new MSD crank tirgger system will cost you more than an e-Sync distributor. In many cases a crank trigger is a PITA to install due to clearance issues in front of the motor. Your current distributor may be worth more to someone else before you modify it.

Jack
Racetronix

 

[WaterPog]

summit lists the crank trigger at $220, Aerospace lists theirs at $190, and you listed the distributor at $299 or am I missing something?

As for the belt alignment, I plan to switch over to the Fox style brackets which sit further out from the block so what I was going to do is just use the SN95 style dampner and pulley with the fox style brackets and waterpump, I may have to actually shim the crank pulley a little bit but i'm going to wait until it's on the car to check for sure.

From what I've seen the MSD 8582 I have seems to be going for ~$100-$150 new, so I'd be looking at spending $150-$200 for the distributor system plus whatever it would cost to have my FAST modified to work with the hall effect-sensors or $220 for the crank trigger which will work with mine . I would expect a more accurate signal from the crank trigger because there is no timing chain or distributor drive gear tolerances to figure into the accuracy.

Is there something I'm missing?

 

[Racetronix]

Let me re-phrase my statement... a new MSD crank trigger system will typically cost you more to buy and install than an e-Sync distributor. If you are able to get parts needed for the conversion cheaply / at no cost and install them yourself then perhaps not?

Many of the late model cars that I have seen seem to require an excessive amount of labor and in some cases custom hardware to get the crank trigger systems to work. I also see a consistent amount of failures with IPU's which leads me to believe that their quality is not as good as it should be. Recently I have diagnosed a few IPU's where they were wired backwards from the factory. I do not know what FAST would charge for the conversion from IPU to hall-effect I/P but it should not be much. If I were to consider a crank trigger system it would be based on a hall-effect sensor as they seem to be more reliable and produce a signal which is less susceptible to interference. Perhaps this is why I am seeing more and more people replacing their HP automotive IPU’s with industrial versions. (Some of which have internal amplification) Having an LED on the back of the sensor also makes roadside replacement super easy and error free.

Jack
Racetronix

 

[NoSlix]

On the mustang, you'll have plenty of room for the crank trigger setup. Do yourself a favor though and order a trigger mount/timing pointer from Reichard Racing. Otherwise you'll have to fab up a timing pointer for the MSD mount. The MSD crank trigger does come with holes for 4 bolt balancers. Do a search and you'll find instructions I gave someone else for setting up their crank trigger. MSD's instructions are for a regular ignition and with the FAST, you want more air gap.

 

[WaterPog]

cool, thanks for the tip shane