550 hp @ 22 psi wtf? On e85

[BruceH]

What are the advertised specs for the parts in your motor? Specifically the compression height of the pistons, connecting rod length, and stroke? If we have this info then calculating deck height can be done. At least then you will know what it should be and can go from there.

 

[palanza7]

Yeah we know all that info, I have it written down and it basically comes out to an 8.7 compression but there shouldn't be a 150 hp difference between 9.8 and 8.7.

Sooo thats why we think something else is going on. Based on below I think the pistons may be in the hole a little bit more than usual....

I jammed a bore scope I bought into the cylinder and I was able to see how far it comes up. You know how at the top of the cylinder there is a ring around the cylinder wall where the piston rings do not come up on?

Here is illustrate, here is a pic I took. At top dead center.

Below that is a video of the piston going up and down to TDC

Soo looking at that.. if we assume that center darker band is the headgasket at a crush of .041.. and right below is is the top of the block.. then based on what I'm looking at it looks just as thick if not more than the gasket.. so possibly its sitting down in two gaskets thick or .081.. and if thats the case, it comes out to a 7.6 compression....................... fuck

Obviously this is pretty rough estimations based on a crappy crappy image but.. its something for sure I think.
If this is the case at least i wouldnt need to rebalance the entire rotating assm and just have the block decked but.. damn =/

https://www.youtube.com/watch?v=TsgxeCxvZDE&feature=youtu.be

 

[01yellerCobra]

If the pistons are as far down as you think blocking the deck and/or heads enough to raise compression would cause more issues like the intake no longer fitting correctly. And it's just a band aid IMO.

Personally I'd either hit the track or take it to another dyno before I start making plans to tear it apart. If it doesn't perform like it should or reads low again then I'd yank the heads off to see what's going on.

 

[palanza7]

If the pistons are as far down as you think blocking the deck and/or heads enough to raise compression would cause more issues like the intake no longer fitting correctly. And it's just a band aid IMO.

Personally I'd either hit the track or take it to another dyno before I start making plans to tear it apart. If it doesn't perform like it should or reads low again then I'd yank the heads off to see what's going on.

Hm yeah I forgot that milling the block would indeed begin to change the position of the intake holes. Well it wouldn't need to be much, I'm sure there is some wiggle room but how much? That I don't know.

Don't really see why I couldn't mill the deck with the shortblock still entirely assembled as long as its handled carefully and cleaned very well after. If that is possible then yeah while technically a bandaid it would save a lot of $

 

[01yellerCobra]

Hm yeah I forgot that milling the block would indeed begin to change the position of the intake holes. Well it wouldn't need to be much, I'm sure there is some wiggle room but how much? That I don't know.

Don't really see why I couldn't mill the deck with the shortblock still entirely assembled as long as its handled carefully and cleaned very well after. If that is possible then yeah while technically a bandaid it would save a lot of $

Milling the deck will cause the same issue as milling the heads. You're removing material where the head gasket sits. You need to disassemble the shortblock because they use the mains to clamp the block to the machine. Not to mention all the metal shavings that would get everywhere and need to be cleaned up.

 

[BruceH]

But what are the dimensions? It's quite possible that the rotating assembly is mismatched from the start with optimistic advertised compression ratio. That's what I'm getting at. You could have a block that is exactly as it's supposed to be with one exception, the advertised compression could be way off because they decided to base it on 46cc heads or something crazy like that.

If you can post the advertised compression height, stroke, connecting rod length, and piston cc it would go a long way toward determining what's going on. It could well be that you simply need a different piston than the standard one that's supplied.

MMR could of speced the whole package wrong. That's why I'd really like to see the advertised specs for the aforementioned parameters, if you have them.

 

[palanza7]

Bruce I gotcha. Here is some info that I got from both Manley direct and Lito. At this point I'm not bothering to even call MMR again.

From Manley: 4.6L

Stroke Options: Stock 3.543, 3.750 stroker or 3.800 stroker
Comp Heights: 1.220, 1.200, 1.170 respectively.

Info from Lito
Rods should be 5.933

Crank is a coyote crank from what Lito and my builder had told me.

Both me, Lito and Manley feel its a -18cc piston at this point.

Here is my invoice description lol

"MMR 4.75 900SE ROTATING ASSEMBLY, 3V +20, ALLOY AND CLOSE TO 9.8**"

I've tried plugging all those combos into various calculators and the only way it goes below 8.5 compression is if the piston to deck is off from what I see.

 

[05stroker]

So, your builder did not measure this stuff during assembly?

 

[palanza7]

So, your builder did not measure this stuff during assembly?

He said he did. Guess not. This is my first time doing all of this, welcome to the school of hard knocks.

 

[BruceH]

Bruce I gotcha. Here is some info that I got from both Manley direct and Lito. At this point I'm not bothering to even call MMR again.

From Manley: 4.6L

Stroke Options: Stock 3.543, 3.750 stroker or 3.800 stroker
Comp Heights: 1.220, 1.200, 1.170 respectively.

Info from Lito
Rods should be 5.933

Crank is a coyote crank from what Lito and my builder had told me.

Both me, Lito and Manley feel its a -18cc piston at this point.

Here is my invoice description lol

"MMR 4.75 900SE ROTATING ASSEMBLY, 3V +20, ALLOY AND CLOSE TO 9.8**"

I've tried plugging all those combos into various calculators and the only way it goes below 8.5 compression is if the piston to deck is off from what I see.

I get it. They didn't really supply the specifics with the parts they sold you.

I'm really wondering what MMR gave you for pistons. There are a whole lot of compression heights available for the 4.6. The reason is because of all the different crank and connecting rod combos that have been used over the years.

At one time I was considering a motor with a coyote crank. I couldn't come up with a combo of piston and connecting rod that wasn't deep in the hole unless I ordered a custom piston with a non standard compression height or milled a piston top down. None of the "standard" 1.220, 1.200, or even 1.150 compression heights would come close to the deck with either 5.993" or 5.850" rods.

I was hoping they had solved the issue with a special manufacture piston that had the same compression height as the coyote piston.

Your pics do seem to show a piston that is pretty deep for a 4.6 imo.

 

[palanza7]

I get it. They didn't really supply the specifics with the parts they sold you.

I'm really wondering what MMR gave you for pistons. There are a whole lot of compression heights available for the 4.6. The reason is because of all the different crank and connecting rod combos that have been used over the years.

At one time I was considering a motor with a coyote crank. I couldn't come up with a combo of piston and connecting rod that wasn't deep in the hole unless I ordered a custom piston with a non standard compression height or milled a piston top down. None of the "standard" 1.220, 1.200, or even 1.150 compression heights would come close to the deck with either 5.993" or 5.850" rods.

I was hoping they had solved the issue with a special manufacture piston that had the same compression height as the coyote piston.

Your pics do seem to show a piston that is pretty deep for a 4.6 imo.

yeah at this point im just considering it pretty much fubar until I get the money/time/energy to try and tear it down. as it is i can't even really sell the engine if I wanted to so no point in giving up....yet

 

[BruceH]

yeah at this point im just considering it pretty much fubar until I get the money/time/energy to try and tear it down. as it is i can't even really sell the engine if I wanted to so no point in giving up....yet

On the plus side 550rwhp is nothing to sneeze at. If it is indeed super low compression you might get more power with pump gas. It takes cylinder pressure to extract the most power from E85.

 

[palanza7]

On the plus side 550rwhp is nothing to sneeze at. If it is indeed super low compression you might get more power with pump gas. It takes cylinder pressure to extract the most power from E85.

Yeah true points. Considering just slapping a 150 nitrous shot on there to pickup the loss HP and call it a day for awhile lol. Seem to find those kits used here and there for 500-600$

 

[swflastang05]

As stated above I would strongly suggest you run it at the track or another dyno before doing anything else, I can tell you that my car only made 539rwp on my local dyno (which is a MD), but it ran 9.73 @ 141 at the track right after that, at 3,720 lbs. Run this on any race calculator and you'll see those numbers are way off! The only thing dynos are good for IMO is of course tuning then after you establish your baseline numbers, you can make adjustments and determine how much you gained or lost.

 

[palanza7]

As stated above I would strongly suggest you run it at the track or another dyno before doing anything else, I can tell you that my car only made 539rwp on my local dyno (which is a MD), but it ran 9.73 @ 141 at the track right after that, at 3,720 lbs. Run this on any race calculator and you'll see those numbers are way off! The only thing dynos are good for IMO is of course tuning then after you establish your baseline numbers, you can make adjustments and determine how much you gained or lost.

Can't say I thought about it that way really. Yeah I guess the only way to know how fast the car is would be to track it. I'm not exactly a seasoned track guy so I'm sure my numbers are going to suck anyway but.. thats a solid point.

 

[05stroker]

Can't say I thought about it that way really. Yeah I guess the only way to know how fast the car is would be to track it. I'm not exactly a seasoned track guy so I'm sure my numbers are going to suck anyway but.. thats a solid point.

Doesn't matter the MPH will tell the tale.

 

[palanza7]

Well, took the plunge and pulled the drivers side head. After some rough measurements it looks like piston to deck is good, but that my pistons are like 18cc I'm assuming my crude eyeball caliper measurments may be a little off since Valve relief looks like it adds a little under 1cc as well. Sooo i guess after i pull the engine I'll do the water cc test to verify then call mmr, not be surprised when they deny me any sort of replacment.

Whats the max cr i can get away with on e85 for like. 22 psi but still be able to use 93 with way less boost? 11 to 1? i think bruce your build was what 11 to 1?

 

[Wes06]

That sucks. You changing your build plans?
Saw you had a lot of stuff listed

 

[Department Of Boost]

Well, took the plunge and pulled the drivers side head. After some rough measurements it looks like piston to deck is good, but that my pistons are like -25cc lol w.t.f. I'm assuming my crude eyeball caliper measurments may be a little off since I've never even heard of a 25cc piston and its probably 22cc. Valve relief looks like it adds a little under 1cc as well. Sooo i guess after i pull the engine I'll do the water cc test to verify then call mmr, not be surprised when they deny me any sort of replacment.

Whats the max cr i can get away with on e85 for like. 22 psi but still be able to use 93 with way less boost? 11 to 1? i think bruce your build was what 11 to 1?

What was the piston to deck?

 

[palanza7]

Well i realized i screwed up the measurement. Went back and its actually 18cc as lito originally thought. So now I'm left wondering exactly what else was screwing me up since it still seemed like i was way low on hp for that compression.

Top of piston to deck was approx .008 plus or minus .001

I did notice the timing chains marked links didnt line up with the sprocket marks but i mean if i wasnt crashing into valves then that couldn't have been that off

Yeah i listed a bunch of stuff for sale.. Im just so pissed and burned out with this thing fucking me over that im considering a full part out and buying a 2016

Next move is to verify stroke i guess. Man if that dyno was fucked up I'm going to be pretty salty yo. I mean the heads are def stock. Strokes supposed to be 3.650 and 5.933 rods i think

Measured the piston at the bottom of the hole to the deck, 3.65 so that's correct