Twins with Twins, Anyone?

kidturbo

kidturbo

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Got the drive boxes lowered last week. Now just waiting to get the lower units back from Cali. Both are together and ready to ship.

While waiting on those to get here, decided to look at the MAP sensor resolution issue again. The 100psi sensor I originally went with works, but usable A/D conversion in tune/table resolution could be improved. We only made mid-50psi boost on the dyno, so 100psi map is kinda overkill.

So I picked up a couple of these 5bar units to see if it helps out in that LOW boost range. In a no MAF setup, the ECM limits fueling mm3 until it sees MAP values increasing. The 5bar true scale is about 75psi. The one I have now is almost 125psi. While you only have a possible 255dec range of values the ECM cab use.

When testing in FL, you could peg the throttles from idle in hi-gear, and there was almost zero response or smoke because the engine load was so high the turbo barely started to spool. While starting in lo-range resolves the issue, would be long trip home if you lost low gear.

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MarkBroviak

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kidturbo said:
I don't always watch Gale Banks videos.

But when I do, I always end up laughing my ass off...

https://youtu.be/TjumzxI-Kko

He liked our dyno run Videos Mark.. Guess we're doing shit right... lol

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Click to expand...

Lol, I would hope so. We put it on the wood and left it there with out issues or a room full of smoke. People give me a hard time on how I dyno stuff but it is the only way to see what is actually going to happen with a setup. I'd rather it fail sitting on the dyno then in the vehicle cause it is a lot easier to fix it here then after the fact. Nothing is bullet proof but Id rather feel 110% confident we know everything we needed to know when we were down with it!:hug:
 
kidturbo

kidturbo

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Got the drives back on, and the boat up on plane last weekend with some bigger props. Achieved a new top speed of like 49mph, before the 1:1 clutch packs slipped in both trannies when she came alive..

Not sure if turning up the line pressure will resolve things, or if both need trans to come out and we go back to the waffle clutch disk design. They never got hot, but puked some fluid out the vent tubes real quick. Both gears still engage, so some positive news... But also have a gear reduction box screaming I NEED ATTENTION on STBD side. Put the Dr. Stethoscope on the gear case and spun shafts by hand. She sounds a bit deep in the gears to me. The gopro videos will hurt your ears.. SO.... Look for that later today.

I would really love to put together a pit crew that can help push things along faster now that we're on the water. If anyone with skills wants to jump onboard for a week or two, I'm thinking of rolling south and setting up shop again in a few days. Better yet, if anyone near water has a shop this big girl will fit in, I'll make your drive easy...

-K
 
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kidturbo

kidturbo

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Thanks Josh. I'll hit him up tomorrow.
Last week I flew another Ryan up from FL to help out. That got the drives on, and few more of our small bugs worked out. I ask him to try an put together a crew from Sarasota / Tampa Bay area since I have plenty of marine support around there.

Checked the trans fluid today, half quart low in Stbd, but doesn't smell burnt. Also checked the gear reduction box on Stbd, no oil pumping to bearings that can see with engine running. Cracked a line, and noda... Dry sumps certainly have their place, but stuck back in a box where you can't see, reach, inspect, or tell crap about it without removing the whole out-drive drive first is probably not best place IMO.

On a fun note, glad I kept the 7 grand tachs.. These bitches bounce 6k and never break a sweat.. On the dyno we pushed em to 4200r loaded, where they fell off a cliff. On the 18" prop dyno, they shook the props loose at 4500 and 30psi boost, then shot past the 5500 defuel limit. This two speed trans in a boat is best comparable to driving a promod on ice.. The revlimt is getting dropped a 1000 before I go back out...
 
kidturbo

kidturbo

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While I can't suggest spinning a Duramax 6k all day long, it's nice to know they can handle it. But reading 100psi on the oil pressure gauges, I said, let em eat... Now to find another set of those Howards rods with pressurized wrist pin oiling. I know Mark is hiding a set back somewhere... LOL

In the cell phone video section above, I shifted at around 3500R and they fell off to about 2k. That didn't work out because the boost fell off, and wasn't enough torque to stay up on plane. However I'm not sure we are getting full throttle, because according to APP_D torque tables, it's only showing 92%. I know that's not always right, but on our dyno logs we showed 100%. The aftermarket throttles have programmable curves, so it's possible to adjust.

If anyone has an LBZ/LMM log file open, please let me know what you see for APP_D values at wide open. And APPS1&2 voltages would also be a big help. On the bench I have a Corvette throttle hooked up the LMM ECU, it only reads about 85% on APP_D....
 
Chevy1925

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How did mark setup the tune? Steve and I usually setup that 90% and above was full throttle to account for any little variables or “floor mats under the throttle” lol.
 
kidturbo

kidturbo

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Maxes out torque tables at 93%. So only calling for around 1100nm at 91% in the tables. So before I jack that down a couple rows, wanted to see what everyone else sees as max value in a truck.

Thing is, the other LMM jet boat we did is seeing this same issue, and running a stock truck throttle pedal and chassis harness. It's only topping out at around 90% with cable disconnected and pushed all the way down by hand. This twin engine boat has 25ft of wire between stick an the ECM. So I could see some voltage loss possible, even on the 12ga wire I ran up there.

I found another post on another forum from few years back about this same thing. But before I start modifying tables, be nice to get an overall take on what's normal.. All the ECM's I have setup, even with the Vette apps show 100% on relative TPS pids no matter what that APP_D shows...
 
2004LB7

2004LB7

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Logs show 100% on mine. No voltage reading though
 

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2004LB7

2004LB7

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I guess I can re-log it tomorrow along with voltage if no one else comes up with something sooner
 
Chevy1925

Chevy1925

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kidturbo said:
Maxes out torque tables at 93%. So only calling for around 1100nm at 91% in the tables. So before I jack that down a couple rows, wanted to see what everyone else sees as max value in a truck.

Thing is, the other LMM jet boat we did is seeing this same issue, and running a stock truck throttle pedal and chassis harness. It's only topping out at around 90% with cable disconnected and pushed all the way down by hand. This twin engine boat has 25ft of wire between stick an the ECM. So I could see some voltage loss possible, even on the 12ga wire I ran up there.

I found another post on another forum from few years back about this same thing. But before I start modifying tables, be nice to get an overall take on what's normal.. All the ECM's I have setup, even with the Vette apps show 100% on relative TPS pids no matter what that APP_D shows...
Click to expand...

i get it. from what steve was telling me, every truck would see a different percentage when he tuned, some very close together with the next or some very different. most likely due to voltage drop, connector resistance, floor mat, crap like that.
 
MarkBroviak

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Chevy1925 said:
i get it. from what steve was telling me, every truck would see a different percentage when he tuned, some very close together with the next or some very different. most likely due to voltage drop, connector resistance, floor mat, crap like that.
Click to expand...
100% correct and on this we were trying keep it as clean as possible so we may have to go about it a touch different if it is going to be an issue...
 
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