M112 - 300 Build for the '56

clintonvillian

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I wanted to start a new thread as the other was cluttered with what ifs … My apologies, but I think I am slowly starting to iron out a few things and wanted to keep this thread strictly looking at the M112 build.

As stated previously I'd ideally like 300 HP and 400 ft-lbs. But if I am sinking this kind of money into it, why stop there....so I would like the option of increasing the boost and maybe going higher. BUT IT HAS TO BE RELIABLE.

Here is what I have:

-87 4.9L
-The head completed: 2.02 Intake, 1.72 Exhaust, 1.72 Rockers, and a CNC Head Port.
-C5AE 240 no hole rods
-Custom sheet metal intake and a Clifford Intake
-Dynomax Headers
-T-5 3.35 1st, 1.93 2nd, 1.29 3rd, 1.00 4th, .68 5th
-2.78:1 Rearend
-Eaton M112 with 2.5:1 drive ratio (I can and may need to go to a larger pulley on the blower as discussed in previous threads).

Discussion/Questions:

1. I have decided 100% on a Holley EFI system (Megasquirt is ruled out). I have not decided on using the HP or Sniper unit yet. I want to discuss each option below.

2. As listed above I have already purchased remanufactured 240 rods with ARP studs, peened and polished. Will these handle the stated power, where's the cut off? or should I sell them and go for the Compstar Rods

3. I have decided to run a water/methanol injection system and for go any type of intercooler. In normal driving I wont be in the boost that much, mainly just once in awhile showing off for other car guys.

4. According to FTF in another post, the Felpro #1024 is about the best Head Gasket out there. What PSI do you think this will hold up to? OR will I need to go to copper and an O-ring (again it is a daily driver so I don't want a leaky head gasket).

5. I have a normal nodular cast crank, will it hold?

6. Which side of the motor should I mount the Supercharger on. Personally I like the drivers side. It just fits better, but will require me to pipe up and over the valve cover to the intake. It also makes bracing the supercharger easier because I do not have to contend with the headers. I think this will also help reduce heat in the supercharger.

Option 1. If I mount it on the drivers side, it eliminates the possibility of using the Sniper system in a draw through setup, due to the additional charge of air in the intake possibly exploding. This forces me to use the HP system with a fuel rail.

I actually plan to run the pulley right through the powersteering pump hole. I have electric power steering installed so I don't need the pump.

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Option 2. Now, if I were to mount it on the passenger side, I could mount it directly to the intake. This gets complicated due to bracing it, and it would require me to relocate the alternator to the driver side, in order to keep my belt routed correctly and have good wrap on everything. Not impossible, but additional work. This does however allow me to use the simplified sniper setup, no fuel rail, easier tuning etc.

6. Ignition (at least in my mind) now thanks to the guys on this forum has gotten simpler.

Sniper: As of now, I can use the TFI unit, Holley harness, and an Aftermarket Ign. Box to control timing. Or if I am lucky they will have the plug and play distributor out by the time I get there.

The other Sniper option is to modify all the vanes to the same width on the TFI distributor and add a crank signal. Then I think the Sniper is capable of controlling the timing without an aftermarket box. (That's what I gather from the Holley forum anyhow).

HP: I can pickup cheap used COP (Or coil near plug rather) from an LS (including plug wires). Reuse the TFI distributor, remove the vanes for my cam signal and create a cap as you guys have mentioned before. The worst part about this will be the bulky harness that comes with it. I'll have to figure out how to clean that up. Or possibly find a donor cam sync. This will require a 60-2 crank trigger.

I guess to summarize things, I'd really like to hear your input on the water/methanol, the 240 rods, head gasket, nodular crank, and which side of the motor/holley system to go with.

I am currently talking to a few different local engine builders. The one that is retired (built for the the Petty's (I think) back in the 80's and 90's), has raced 240's and 300's before, but I doubt he has any experience to help me with the fuel injection if I need it. He seemed very interested in helping build the six. The other is younger and worked for Joe Gibbs racing. Currently builds $20k plus turboed engines for mudders. I think with tuning he would be able to nail it down, but I am not so sure I can afford him, nor do I think he is that interested in my project.
 

clintonvillian

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I also wanted to add that I actually intend to make a move on this motor this spring. The sheet metal work is almost finished, so I want to get the motor out to my machinist while I am priming and painting. I know its been a lot of talk and not much action but I see some light at the end of the tunnel....
 

pmuller9

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As you know there has been one broken 240 rod that destroyed a turbocharged engine.
There was detonation at 20 lbs of boost. Rod failed sometime afterwards.

A turbocharger is much easier on connecting rods than a supercharger.
A turbocharger doesn't take power from the engine by way of the connecting rods.
In a supercharged engine the rods see the power at the flywheel plus the power it takes to drive the supercharger.
I wouldn't trust the long 240 rods.

The much stouter Compstar rod is shorter than the 240 but longer than the 300 rod and will allow a longer piston skirt for better stability in the bore than the 240 rod.

Stay with the supercharger on the driver side.

The HP will let you run an intercooler.
It has many features not found on the Sniper
It has safety features to protect your engine like Lean or rich safety, knock control ..ect.
It has integrated water injection control
Any style of ignition.
Data logging.
The list goes on.

You don't have to modify the vanes in a TFI distributor.
The leading edges are equally spaced for ignition and injection timing.
The trailing edges have the one spacing difference as the marker for #1 cylinder.

I'm wondering if a magnet was installed in the side of an aluminum cam gear, if a 3 wire Hall Effect sensor mounted to the timing cover would pick it up for a cam sync signal?

So far the cast crank has not given any problems with street level rpm and power.

Water/Methanol injection will greatly reduce the chance of detonation, make more power and keep the cylinder clean from carbon deposits.

The Eaton 112 supercharger rpm should be limited to 14,000 rpm
 

clintonvillian

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Okay...looks like I got a nice set of rods for sale....

Now, just to be clear avoid an inter cooler and go to meth injection.

Where would be the optimal place to inject? Befor the super charger, right after? Or into the untake attache to the motor? Or does it really matter?

In regards to the TFI distributor, i know it has a thin vane. Im pretty sure someone on Holley is using them because they are cheaper than ds2s, but they said that reducing them to one vane provides a much clear signal???
 

pmuller9

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Since the engine will spend most of it's time cruising with low to no boost you can skip the intercooler.
It would be important that the engine DCR not exceed 6.5.

If you run the water/meth injection into the inlet of the supercharger it will help cool it along with the incoming air.
I'm assuming you will be using the supercharger bypass valve during cruise.

The TFI distributor has a Hall Effect sensor which provides clean 12 volt square wave.
It wont hurt if you make the vanes all the same width providing you can machine the edges square and have the exact same spacing.
 

Firepower354

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Guessing you have this, but...
[image]http://i58.servimg.com/u/f58/11/60/77/43/eaton_13.gif[/image]

With driver side mounting, the crossover piping could be extruded/finned tube, of thousands of sizes and shapes. If the engine bay is well vented.

The blow-thru carb guys see over 100 degrees of charge cooling difference between before and after carb. A TBI should be similar.

Draw-thru remote-mount, seems like there's be puddling and poor mixture distribution. And maybe 'sploding?

Water/meth is hard to distribute equally in a complex intake, based on some instrumented testing I was watching. AussieSpeed should excel there.

High pressure W/M and 6 small nozzles, as far up the runner as you can?

Holley HP with the injectors moved back to the bend of an EFI lower, aimed right at the valve, seems a good compromise, allowing decent evaporative cooling, uniform distribution. Batch fire is "easier" but sequential allows per-cylinder changes, if you add O2 sensor bungs. Way over my pay grade, but "they say" it can be done.

With some of the cheap aftermarket and OEM reluctor wheels, one could ditch the distributor butt-fur the oil pump drive.
I'm in Flint MI, and way more GM familiar, but the 411 ECM is widely supported, and the way I'm going on my L18/L29 mashup, and probably on the 12-port I'm building Pops. 28x crank and 1x cam/distributor pickups are all that are needed.
 

pmuller9

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It is supposed to be there. Looking good!
It there room to put a trigger wheel behind the harmonic balancer?
 

clintonvillian

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Yeah, I had a lip machined on it for one.

Question, the MAF sensor typically goes in the intake prior to the throttle body. I have 10" to get a cone style air filter on....see the dilemma...

I had considered cutting a hole and running the intake through the inner fender, but man I really dont want to hack those stainless fenders...
 

pmuller9

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Why not use a MAP censor in the intake manifold instead?

A 3 inch pipe is fine.
How many square inches in the intake manifold inlet?
 

THE FRENCHTOWN FLYER

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Make sure to leave enough clearance in the firewall recess so you can pull the valve cover off if need be. Nice install
 

clintonvillian

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THE FRENCHTOWN FLYER":2jzjnwn1 said:
Make sure to leave enough clearance in the firewall recess so you can pull the valve cover off if need be. Nice install

I was eyeballing that rear bolt on the cover...Im not sure how Im going tonget to it....

I thought about maybe a rubber plug in the fire wall I could remove, and then access the bolt feom in the cab.
 

pmuller9

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clintonvillian":23kqivg4 said:
Question, the MAF sensor typically goes in the intake prior to the throttle body. I have 10" to get a cone style air filter on....see the dilemma...

Instead of a MAF sensor why not use a MAP sensor in the intake manifold?
 

guhfluh

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This thread bounces all over, so I'm not sure what has been decided, but...

Not all TFI distributors have an unequal vein pattern, only the late 95-97 sequential injected engines.

Unless you have a modified damper for the SC already, a late 95-97 harmonic damper has the crank trigger space already machined on the back of it.
 

clintonvillian

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Guhfluh...I actually pulled the TFI unit apart and went to the autoparts store...

The TFI unit I have is from an 87, and has 5 thick veins and one thin. I would prefer NOT to run the TFI unit. Ive heard it is finicky.

Now I looked at multiple cam synchronizers/position sensors. I had hoped the 2005 taurus would work...no dice, it was close but the diameter was to small. It was also a 2 wire, so I think that it is a VR unit.

I have a couple others on order to look over and try. My concern os that the majority of those will be 2 wire as well.

I ordered a 96 4.9 distributor, which is supposed to have the sensor in it. We will see...
 

guhfluh

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In general, MAP based Speed Density is what is preferred in a boosted application. It is rare, but some tuners still like MAF based tuning in boost. I believe the HP is able to do either, but MAP is what I'd recommend.

A 96 4.9L distributor should be the same hall effect pickup TFI as the earlier 4.9L TFI distributors. I have been under the impression that the shutter wheel changed in late 95 for the MAF based sequential injection 4.9L trucks and the earlier ones were batch injection without the small vein signature.
 
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