2008 ROUSH Stage 3 Build...Take III

[Wes06]

You have no heart If you would laugh at a man who is on his 3rd engine build.
Karma is a bitch.

No I'm laughing at MMR providing shit.

Don't curse me my engine is apart to install DOB as we speak

 

[BruceH]

can you please explain how you get your calculations?

Explain what? Stock piston in the hole is right around -.008" on the ones I've measured which has only been a few.

If it's about the pistons sticking out of the hole that's pretty simple. A 3.800" stroke will need a compression height of 1.150" combined with a stroke of 5.850" to reach a stock piston depth. Since his box is marked 1.170" compression height that would indicate that the piston tops are .020" taller than they should be. The difference between -.008" and .020" is .012". Obviously there will be a small tolerance stack with parts, especially aftermarket parts but the ballpark estimate is going to be pretty close.

A bigger question is why do they have pistons with a non standard compression height? Is it for use with the 5.0 crank and stock rods? If so then why did they sell them to him for his 3.800" stroke with 5.850" rods combo? Maybe they didn't understand the intended use? Maybe there is some other reason.

 

[thump_rrr]

Explain what? Stock piston in the hole is right around -.008" on the ones I've measured which has only been a few.

If it's about the pistons sticking out of the hole that's pretty simple. A 3.800" stroke will need a compression height of 1.150" combined with a stroke of 5.850" to reach a stock piston depth. Since his box is marked 1.170" compression height that would indicate that the piston tops are .020" taller than they should be. The difference between -.008" and .020" is .012". Obviously there will be a small tolerance stack with parts, especially aftermarket parts but the ballpark estimate is going to be pretty close.

A bigger question is why do they have pistons with a non standard compression height? Is it for use with the 5.0 crank and stock rods? If so then why did they sell them to him for his 3.800" stroke with 5.850" rods combo? Maybe they didn't understand the intended use? Maybe there is some other reason.

I was looking for the formula but I figured it out myself.
(stroke/2 + rod length + compression height) - deck height = Piston to deck clearance.

His Motor

Deck height on a stock modular 4.6L is 8.937"
Stroke is 3.800"
Rod length is 5.850"
Compression Height is 1.170 as per the box

[(3.800/2)=1.9 + 5.850 + 1.170] = 8.920 - 8.937 = -0.017" (under deck height)


Factory 4.6L 3V

Deck height on a stock modular 4.6L is 8.937"
Stroke is 3.543"
Rod Length 5.933"
Stock Compression Height 1.220"
[(3.543/2)=1.7715 + 5.933 + 1.220 = 8.9245 - 8,937 = -0.0.125" (under deck height)

Using your numbers

Stroke 3.800
Rod Length 5.850
Compression Height 1.150
[(3.800/2)=1.9 + 5.850 + 1.150] = 8.900 - 8.937 = -0.037" (under deck height)

 

[BruceH]

I was looking for the formula but I figured it out myself.
(stroke/2 + rod length + compression height) - deck height = Piston to deck clearance.

His Motor

Deck height on a stock modular 4.6L is 8.937"
Stroke is 3.800"
Rod length is 5.850"
Compression Height is 1.170 as per the box

[(3.800/2)=1.9 + 5.850 + 1.170] = 8.920 - 8.937 = -0.017" (under deck height)


Factory 4.6L 3V

Deck height on a stock modular 4.6L is 8.937"
Stroke is 3.543"
Rod Length 5.933"
Stock Compression Height 1.220"
[(3.543/2)=1.7715 + 5.933 + 1.220 = 8.9245 - 8,937 = -0.0.125" (under deck height)

Using your numbers

Stroke 3.800
Rod Length 5.850
Compression Height 1.150
[(3.800/2)=1.9 + 5.850 + 1.150] = 8.900 - 8.937 = -0.037" (under deck height)

Are you using 5.4 numbers? I ask because just off the top of my head a stock 5.4 is about .125" in the hole. A stock 4.6 is not.

 

[thump_rrr]

Are you using 5.4 numbers? I ask because just off the top of my head a stock 5.4 is about .125" in the hole. A stock 4.6 is not.

Nope

Deck Height 10.079"

Stroke 4.017"
Connecting rod 6.657"
Compression height 1.220

2.0825 + 6.657 + 1.220 =9.9595 - 10.079 =-0,1195

The 5.4L is supposed top be -0.120"

 

[BruceH]

Nope

Deck Height 10.079"

Stroke 4.017"
Connecting rod 6.657"
Compression height 1.220

2.0825 + 6.657 + 1.220 =9.9595 - 10.079 =-0,1195

The 5.4L is supposed top be -0.120"

Obviously 4.6 numbers. Still, something is off in your formula. Even my current motor is around .010" iirc. It's a stroke of 3.750 and 1.200" compression height. All of the stock stroke motors I've assembled came out right around .008" as have the couple of stock 4.6 I've taken apart. The only one that was less had a decked block.

Edit: You are a Ford dealer guy and have access to the manual. Could you look up the stock 4.6 Ford spec for where a stock piston is supposed to be?

 

[stang67]

I could be wrong but , to me those plugs look alittle lean

 

[one eyed willy]

Boost is a measurement of restriction. The less obstructions the less "boost". I'm not sure on how the bypass valves work on superchargers and all that jazz, but for a turbo car, when I changed my intake manifold, I lost about 2 psi on my boost gauge. Everything felt the same, if anything felt more powerful at a lower boost. With the bigger blower and new stuff you have I would expect it to drop, but I don't know how a supercharger regulates its boost.

 

[Cali HP Addict]

Great build thread. Been watching it for a while and I really like your attention to detail.
Just remember the big picture. You built a beast and you have accomplished it. It's when we aren't satisfied and we push it that we blow em up. Again... Tune that thing safe and enjoy the hell out of it. You have all the time in the world to tweek it.

 

[AutoXRacer]

Boost is a measurement of restriction. The less obstructions the less "boost". I'm not sure on how the bypass valves work on superchargers and all that jazz, but for a turbo car, when I changed my intake manifold, I lost about 2 psi on my boost gauge. Everything felt the same, if anything felt more powerful at a lower boost. With the bigger blower and new stuff you have I would expect it to drop, but I don't know how a supercharger regulates its boost.

Everything below the blower is the same...except for the MMR pistons.
The back pressure should be the same. VMP claims this blower makes more boost without any other changes. So I am currently spinning the blower faster (2.8" pulley) to get less boost than before (3.0 pulley).

I did change the throttle body from a mono-blade to the VMP 67mm twin. So I should expect some restriction there. But not enough to drop 4 PSI!!

The bypass valve works off a diaphragm exposed to vacuum. When vacuum is present, it opens the valve, when vacuum is lost it closes the valve.

See the picture below, its the little circle bypass valve at the top of the image.

 

[one eyed willy]

I'm guessing there should be a way to diagnose a bypass valve problem? What does VMP say about the drop?

 

[eighty6gt]

Good idea, make sure the bypass is closing fully.

 

[stang67]

Who installed the bypass cause when Pse superchargers did mine they said the bypass had to be adjusted properly or it would cause issues

 

[AutoXRacer]

I'm guessing there should be a way to diagnose a bypass valve problem? What does VMP say about the drop?

Nothing much, they are blaming my rotors. But in all fairness, they are busy with race season.

I am hoping VMP let's me try another blower.

Who installed the bypass cause when Pse superchargers did mine they said the bypass had to be adjusted properly or it would cause issues

I installed the bypass valve per VMP instructions. Preloaded the valve slightly. I had marked the position of the bracket.

 

[one eyed willy]

maybe throw a go-pro next to the bypass while doing a WOT pull to see if its opening?

 

[AutoXRacer]

maybe throw a go-pro next to the bypass while doing a WOT pull to see if its opening?

I don't have a go pro and the bypass is buried in there. I will bring my borescope though and see if it moves at WOT.

It should actuate during vacuum, but as soon as WOT hits, it should close and not move.

More to come.

 

[eighty6gt]

Those rotors should be functioning better than when Eaton released them, should they not?

Was the housing machined or replaced?

 

[AutoXRacer]

The rotors were repaired/resurfaced.

Here is the damage that I found:

Although I was told this is typically wear from OEM blowers...
I had Stiegy refinish the rotors:

So the rotors look a lot better than they did. Plus Stiegy claims the new coating is 100% better than Eatons...something running cooler and better airflow.

The case has been replaced with a VMP GenII case which is claimed to make 40-60HP without any other changes. Its supposed to make more boost.

This is what my original ROUSH case looks like:

Even in this condition, last time I was running the motor, it made 14 PSI with a 3.0" pulley and the mono-blade throttle body.

You would figure with a new super case and refinished rotors it would make the same or more boost.

Everything was put together by Stiegy. I shipped my ROUSH blower and the VMP case to Stiegy and they speced everything and put it together.

With the new VMP GenII case we were expecting more power, thus we were expecting to de-tune the motor further. Instead, we are currently running more timing and spinning the blower faster making less HP than before.

 

[thump_rrr]

Do you still have the old pistons?

 

[AutoXRacer]

Do you still have the old pistons?

Yes, both sets. Why?