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Simon Motorsports upgrade of 350 Verados

Old 11-19-2019, 11:26 AM
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Originally Posted by 32 sun View Post
-a mechanical fuel flow device potentially inhibits fuel flow. not a good idea on supercharged engine running above stock boost. I did see that issue in a review of the GRS10, event though Garmin's specs say it will flow up to 50GPH and has a 1psi restriction at 40psi, those specs should work as I believe my true fuel flow is in the 40-45GPH range.
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if the paddle wheel sticks or breaks then it's a different story. at 15 psi boost you can cook your motor in seconds if you suddenly restrict fuel flow and lean out at wot. i would not do it.

let me give you an analogy. in the early days of efi back in the 90s companies used a vaf to monitor air flow for the ecu instead of a maf sensor. a vaf sensor is sping loaded flap that tells the ecu how much air is flowing based on air pressure. a maf sensor uses a fixed sensor. several cars were produced that were identical year to year except for the switchover to maf (same ecu map and same injectors). toyota supra is the classic example. you could reliably boost a maf vehicle more than a vaf vehicle. this was simply because there was the chance of mechanical failure of the vane flap under boost conditions. no other variable. if the flap failed even a little, you went lean and cooked your motor.
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Old 11-19-2019, 12:02 PM
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Originally Posted by 32 sun View Post
-a new motor the ecu fuel flow report should be very accurate because clean new injectors are very precise and do what the ecu tells them to do. Agreed in theory, but from my data I would guess the issue is the engine ecu "massages" that data through a table to give more consistent readout?
pretty sure it is not massaged. it is just the calibrated output of the injectors at a given voltage.

possibly the motor has a rising rate fuel pressure regulator that the chip is varying to a higher psi without the ecu knowing about it. the ecu is thus assuming fuel is entering the injectors at stock psi but the higher actual psi is boosting the injector output. if so and if you can find out how much they up the fuel rail pressure you could calculate your real fuel economy as a simple multiplier of your current readout.

or they are leaning the motor out.

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Old 11-19-2019, 12:23 PM
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Originally Posted by suzukidave View Post
pretty sure it is not massaged. it is just the calibrated output of the injectors at a given voltage.

possibly the motor has a rising rate fuel pressure regulator that the chip is varying to a higher psi without the ecu knowing about it. the ecu is thus assuming fuel is entering the injectors at stock psi but the higher actual psi is boosting the injector output. if so and if you can find out how much they up the fuel rail pressure you could calculate your real fuel economy as a simple multiplier of your current readout.

or they are leaning the motor out.
I guess that is possible, seems like it would take a lot of additional fuel pressure, but maybe. Seems like we also have to figure out how they are getting additional boost without it showing up on the vessel view. If just additional fuel was added without additional boost it would just be very rich and not make much more power.

What I got from Simon:
-More power, but I don't understand how, and I believe the fuel flow is not accurate.

What I wanted from Simon:
-More power, clear explanation of how it works, accurate display of all engine parameters.
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Old 11-19-2019, 02:57 PM
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Originally Posted by 32 sun View Post
I guess that is possible, seems like it would take a lot of additional fuel pressure, but maybe. Seems like we also have to figure out how they are getting additional boost without it showing up on the vessel view. If just additional fuel was added without additional boost it would just be very rich and not make much more power.
it might be part of what they do rather than the whole difference, but i agree with you in general that another 100hp from that little motor without more boost seems far fetched. what is the wot boost on the stock 400? is it more than 15-16 psi?

if fuel flow is not correct then boost might be wrong also. could be the same issue with the ecu thinking it is sending stock boost voltage to the boost controller when it is not. maybe the fuel mapping on this engine is not infinitely scaled so they had to fool the ecu that it is running within stock parameters.
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Old 11-19-2019, 05:11 PM
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Originally Posted by suzukidave View Post
it might be part of what they do rather than the whole difference, but i agree with you in general that another 100hp from that little motor without more boost seems far fetched. what is the wot boost on the stock 400? is it more than 15-16 psi?

if fuel flow is not correct then boost might be wrong also. could be the same issue with the ecu thinking it is sending stock boost voltage to the boost controller when it is not. maybe the fuel mapping on this engine is not infinitely scaled so they had to fool the ecu that it is running within stock parameters.
Yes, can someone with stock 400 Verados please confirm WOT boost and fuel flow numbers?
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Old 11-20-2019, 03:40 AM
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They’re not raising boost. That can only be accomplished by changing the supercharger pulley.
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Old 11-20-2019, 06:29 AM
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Originally Posted by davidwademarine View Post
They’re not raising boost. That can only be accomplished by changing the supercharger pulley.
I believe Verado engines can raise boost as the waste gate is electronically controlled and does not fully close with 350 or 400HP calibrations. The Verado engines are known as having much better power than naturally aspirated engines in hot conditions, because they can compensate by increasing boost. At one point with this boat I put a new set of props on to test and the one on the port engine was made incorrectly, 28 pitch instead of 25, while the starboard had a 25 on it. I noticed the port engine was low on RPM and assumed it was an engine power issue. Told my service dealer about it and also noticed the port engine had much higher boost than starboard at all speeds. Thought is was weird to have low RPM and high boost, but the dealer tech was not surprised, said the engine ecm will increase boost in an effort to compensate for lower RPM. Changing out the bad prop fixed that issue.
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Old 11-20-2019, 06:59 AM
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Originally Posted by 32 sun View Post
I believe Verado engines can raise boost as the waste gate is electronically controlled and does not fully close with 350 or 400HP calibrations. The Verado engines are known as having much better power than naturally aspirated engines in hot conditions, because they can compensate by increasing boost. At one point with this boat I put a new set of props on to test and the one on the port engine was made incorrectly, 28 pitch instead of 25, while the starboard had a 25 on it. I noticed the port engine was low on RPM and assumed it was an engine power issue. Told my service dealer about it and also noticed the port engine had much higher boost than starboard at all speeds. Thought is was weird to have low RPM and high boost, but the dealer tech was not surprised, said the engine ecm will increase boost in an effort to compensate for lower RPM. Changing out the bad prop fixed that issue.
Boost is a measure of restriction

28P prop on one engine=more load=more restriction
The starboard/25P engine was running more efficient, therefore less boost at the same(or more) RPM, making the same power essentially
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Old 11-20-2019, 07:23 AM
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They add power though timing advance and fueling. The wastegate is kept shut at lower revs but it’s only going to make so much boost with the given pulley.
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Old 11-20-2019, 09:47 AM
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Manufacturer's need to install a software patch to stop non OEM affiliated company's from modifying their stuff.
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Old 11-20-2019, 09:49 AM
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Originally Posted by jvoisel View Post
Boost is a measure of restriction

28P prop on one engine=more load=more restriction
The starboard/25P engine was running more efficient, therefore less boost at the same(or more) RPM, making the same power essentially
Is boost not a measure of pressure? Specifically manifold pressure? Absolute pressure?
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Old 11-20-2019, 10:34 AM
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Originally Posted by alloyboy View Post
Is boost not a measure of pressure? Specifically manifold pressure? Absolute pressure?
Boost is a measurement of how much extra air is NOT flowing. You could keep everything exactly the same except port the head for better flow and the boost will actually decrease.
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Old 11-20-2019, 01:30 PM
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I did the Simon 250-330 upgrade. Very happy with the performance and posted curves on THT. The raise the rpm limit and Simon recommends propping it to the high end. Don’t know the specifics but sucks a lot more fuel in the 5000+ rpm range. Happy with it, took a few prop changes to dial it in.
My understanding from contacts in FonduLac is that they are locking the ecu on newer engines. Assume someone will hack it.
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Old 11-20-2019, 01:33 PM
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Originally Posted by syrupdawg View Post
Boost is a measurement of how much extra air is NOT flowing. You could keep everything exactly the same except port the head for better flow and the boost will actually decrease.
In what units is boost measured?
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Old 11-20-2019, 01:48 PM
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Originally Posted by alloyboy View Post
Manufacturer's need to install a software patch to stop non OEM affiliated company's from modifying their stuff.
Wheres the fun in that? To me having an engine that can be upgraded with an aftermarket tune in a couple minutes is a huge plus over other motors that cant have that done. However i think its fair if they void warranty.
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Old 11-20-2019, 03:08 PM
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Originally Posted by syrupdawg View Post
Boost is a measurement of how much extra air is NOT flowing. You could keep everything exactly the same except port the head for better flow and the boost will actually decrease.
this guy understands.
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Old 11-20-2019, 05:12 PM
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Originally Posted by alloyboy View Post
Manufacturer's need to install a software patch to stop non OEM affiliated company's from modifying their stuff.
Toyota, Audi, vw, Porsche etc have tried to do this, but all that happens is people find workarounds. There are always ways to get into the ECUs as there have to be for the manufacturers to update them.
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Old 11-20-2019, 06:02 PM
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Originally Posted by drkptt View Post
In what units is boost measured?
Measured in PSI but think of it as forcing something where it doesnt belong. If it fits right it slides in easy. If it doesnt go easy the more pressure it takes to push it in.

A naturally aspirated engine pulls a vacuum in the intake.
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Old 11-20-2019, 08:45 PM
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Originally Posted by alloyboy View Post
Is boost not a measure of pressure? Specifically manifold pressure? Absolute pressure?
Yes, boost measured in PSI. Some factors I see:
-Supercharger is a pump connected to the crankshaft, so maximum air volume output is mostly related to RPM (and a some design factors, flow, etc.) but mostly RPM.
-Some folks have made the point that the pump is feeding the engine (cylinder heads, intake valves, etc.) and the rate at which they take air can effect the resulting pressure, true.
-Also in that closed system between the supercharger output and engine intake is the electronically controlled waste gate, instantly adjusting the amount of air being bleed off to control boost pressure.

Now some factors I have observed, but not yet relieved here:
-Stock the boost ran from 0 to ~15PSI, 0 at RPM below ~2000 and throttle less than 20%, then pretty linear scale to full boost at WOT.
-The pressure will reach 15PSI during acceleration long before full RPMs are reached. With the stock 27 props (6100 max RPM) if you trimmed the engines all the way in and put the tabs down you could limit WOT RPM to <5000, but boost would hit 15PSI at probably 4500 before you even got to full speed. Then you raise the tabs, trim the engines out, hit 6100 and the boost just holds steady at 15 the whole time.
-If you are cruising down the lake at say 50mph, 4000 RPM, 5psi of boost, and hammer the throttles while watching the boost, the first thing you will see is boost shooting up (no drop, then rise with RPM, as you would expect with a non-waste gate system).
-Hot weather versus cold weather, 15PSI

What does the above tell me? That the waste gate is the controlling factor. Mercury set a 15PSI limit on boost for the 350 and the waste gate maintains that. Also, that the pump probably has lots of extra capacity. If it can hit 15PSI at 4500 Then turning (pumping) much faster it should be able to achieve higher pressures.

-When I installed the new tune and the full speed WOT RPM went up to 6400 and speed increased ~4MPH the boost still stayed at 15PSI.
-Changed to 25P props and full speed WOT RPM went up from 6400 to 7000, still 15PSI
Those last 2 points make no sense to me, I totally expected to see 20+ PSI and also PSI varying with load/RPM as I figured the new software would just close the waste gate and achieve max boost, then adjust the injectors to enough fuel flow to achieve the correct mixture.

Something is fishy with the fuel flow and boost, I do not believe the numbers after the tune are correct, would like to know more about how the tune works.
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Old 11-20-2019, 10:43 PM
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Originally Posted by alloyboy View Post
Manufacturer's need to install a software patch to stop non OEM affiliated company's from modifying their stuff.
that could be quite easily done, but someone would find a "hack" they could also make it impossible to do "stuff" without leaving a trace, I once read (on the internet, so it must be true) that some companies want people to tinker, it is kind of like R&D but at no cost, if it fails, it's not their problem!
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