Upgrade Ignition

[PatinIdaho]

Currently i have a Delco Voyager ignition but im thinking a Mercruiser Thunderbolt V system would be a good upgrade as it adjusts timing on the fly and uses a knock sensor.
After doing some reading it seems like its about as close as you can get to computer control with out a actual ecm/o2 sensor.
Any thoughts?
Boat is a 1984 245 Bayliner with 260HP 5.7 and a DP lower

 

[Scott Danforth]

Your Delco voyager adjust timing on the fly

You 1984 block wouldn't have the bosses for the knock sensors

 

[PatinIdaho]

Thanks Sott!
So here is the low down.(short version)
The knock sensor is mounted into the lower engine drain of the block as the pics will show 1 is a VP pic and the drawn one is from the Mercruiser manual.
Mounting the knock sensor is not a problem.

The Delco unit only fallows a pre programed advance curve depending on the module selected and RPM. It was designed as a "Limp Home mode" for autos that just happens to work decent on a marine engine.

The Thunderbolt V is different.
Idle speed spark control.(Helps to maintain engine idle speed)
Acceleration spark advance(Advances spark during acceleration over base advance as long as no detonation is detected)
Mean best timing spark advance(Finds best advance for a steady cruising rpm)
Rev limiter
Knock retard spark control(helps to prevent engine damage from detonation)

I would think this is the best ignition system you can get for a 5.7 carburetor boat engine without going full ecm setup.

 

[PatinIdaho]

No Title

Well dang it will not let me upload the other pic

 

[Bondo]

Ayuh,.... Yer gonna waste a ton of money, for Zer0 performance up-grade,....

I don't dispute that the T-Bolt ignition is no doubt the very Best boat ignition even built,........
But,.....
The T-Bolt, bein' Merc. is Stupidly expensive,....

DonS always suggested goin' to the Delco Voyager if a major T-Bolt component died, insteada fixin' the T-Bolt,....

 

[PatinIdaho]

There has to be some improvement someplace or why would they design anything over the T-4?
Would i see more speed. Probably not?? but other things should improve as more timing with out detonation is better as you get a better LPCP and that equals more torque
I would think i would see better fuel economy if even only slightly at cruse.
Better acceleration. I would think so as the T-5 can give more advance then the Delco when accelerating.
I probably will not feel much difference but i bet i see a difference at the gas pump + i can get the entire setup for $300 from a wrecked boat being parted out.

 

[Scott Danforth]

There is zero impact on fuel economy changing ignitions.

 

[PatinIdaho]

here is something else i found on this forum.

I am an engineer. I am very familiar with the t-bolt IV and V and its functions.

I would lean toward getting the t-bolt V components and switching back. Yes, I know what it cost, but heres my opinion and why.

The t-bolt has a very hot spark. If you remove the spark cable from the center tower and crank the engine, a bright white spark will jump from the center tower to one of the coil terminals. And, that's while the battery is at 8-9 volts while cranking. The plugs in that engine were chosen to work with that spark intensity, and ignite teh fuel throughly. Note: you MUST use the merc coil with the t-bolt series systems. I even tried a MASCAR grade coil and the boat ran badly.

Next, and this is the most important part. The timing is done in the pack, not the distributor. The t-bolt ignition systems have a memorized advance curve.
This was adaquate and produced reasonable power for the RPMs. The t-bolt V has a knock sensor. The system will advance the timing until it knocks and back it off until it stops. So, simply put, the system operates the timing at the best spot for whatever conditions, gas grade, sea conditions, etc will allow. This makes HP better and even results in a slightly better fuel burn. Their specs state as much as 10 degrees, + and -.
My 5.7 has the t-bolt V. Its rated at 250 HP. The same engine and carb with the t-bolt IV was rated at 220-230 HP. SO, you can see the benefits of teh V.

Next, the t-bolt systems were designed time engines for a marine loading. Its wayyy different. Like in a car or truck, you may use 200 HP accelerating to hi-way spped, and use maybe 30 HP to keep it there.
If a boat requires 120 HP to cruise, you are using 120 HP all the time.

Lastly, if the timing is advanced too far, it may burn a hole thu a piston top.
As an engineer, I learned not to second guess someone elses design. They do a lot of testing and have to warranty it for up to 7 years. they certainly don't want to give you another engine for free.....

 

[Scott Danforth]

I am an engineer. I am very familiar with the t-bolt IV and V and its functions.


My 5.7 has the t-bolt V. Its rated at 250 HP. The same engine and carb with the t-bolt IV was rated at 220-230 HP. SO, you can see the benefits of teh V.

So the different heads, and the roller can have nothing to do with the HP increase? Its all in the ignition?

My 5.7 liter motor after I played with it was over 300hp (about 330 at the flywheel). I suppose the cam, roller rockers, vortec heads, and intake had nothing to do with that either. Guessing I should have just put in a TBV.....

Spend your money, don't spend your money. However guaranteed you won't get any performance change.

 

[Bondo]

Spend your money, don't spend your money. However guaranteed you won't get any performance change.

Ayuh,.... Ditto,....

 

[bruceb58]

My 7.4L engine in my Volvo has a proprietary ignition in it which uses knock sensors to adjust timing. I am switching it out to a Voyager and have the distributor in hand ready to install.

Guess what...Volvo switched to the Voyager in later year engines.

I agree with Scott....the increase in HP was not due to the ignition.

 

[H20Rat]

One of my hobbies is ECU hacking on vehicles... If ANYONE would be an advocate of a more advanced ignition, I'd be it, but in a marine environment, those advanced features do almost nothing. Boats don't deal with uphill, downhill, coasting, variable loads, transmissions, etc... They swing a prop that is a fixed size through a medium that is a relatively fixed density, and move a boat that doesn't change load more than a small amount. The demands of the ecu/ignition are almost static compared to what a car engine goes through. Because of that, all the advanced tuning features are almost useless. Yes, it technically might gain a couple HP and maybe a little mileage, but not enough to actually notice.

 

[Muisak]

Well dang it will not let me upload the other pic

You may have just saved me friend... I have a mercruiser 5.0 efi i'm working on, and when I got the boat this sensor was just laying off to the side. Trying to figure out where this bad boy goes. Not sure why anyone would have removed it.... the engine does seem to run fine without it, but I haven't had it in the water as of yet.