Mercury Opti Air Pump...

[Tango]

Has anyone ever tested an Opti air pump with a custom lighter piston? I can only assume that using a higher quality, lighter piston could be a benefit in keeping the pump together at higher RPM with a greater efficiency.

I have custom pistons made all the time for specialty cars like a Nissan GTR or other boosted vehicles.

When these pumps fail... what is typically the culprit?

Thanks!!

[gorillapowered]

Interesting.... subscribed! The 2 that I blew up at high RPM's actually ate a reed. Maybe just me, but it was like the reeds could'nt handle the rpms. Would be a cool performance kit. Light weight piston and and a performance reed set.

[XstreamVking]

I would like to know the rpm's the pump is doing at 6000 motor rpm's. IMO The rpm's could be reduced by an under drive pulley if the air press numbers would still be hi enough.

[life is good]

I believe the failure point of these compressors was always in the crank bearing area. The older compressors only had a bearing on the top of the crank so bottom was unsupported. I don't think the piston was actually the problem.

[Tango]

I believe the failure point of these compressors was always in the crank bearing area. The older compressors only had a bearing on the top of the crank so bottom was unsupported. I don't think the piston was actually the problem.

Exactly... but with a lighter piston and adding ceramic coatings, the load to the bearings would be less. Following this line of thought... the reliability should be much greater for extended RPM usage and a lower parasite drag. Something like this might actually free up some power.

[powerabout]

200xs with ssm redline at 8000 so Merc must have tested that?

[Tango]

200xs with ssm redline at 8000 so Merc must have tested that?

My thoughts exactly... Tested, proven but they have a support truck with fresh parts each race. They wouldn't run fifty hours in a full season... Let alone a few hundred hours fifty plus miles offshore. Does anyone have a pic of one of the 200XS SS motors? Do they use the lighter aluminum Opti pump pulleys?

[flabum1017]

Or go bigger bore for more displacement and slow it down..................

[Tango]

Or go bigger bore for more displacement and slow it down..................

I thought of that, but believe it would put more load on the already failing bearings. Going larger to slow it down would also need a new rod and bearing. The compressor cranks have shown signs of failures related to journal material flaking or galling.

Any more thoughts on this?

[gorillapowered]

It would take a lot of technology and technical knowledge that surpasses me, But I always wondered what it would take to run a external electric type compressor/ air source. I would be a solid bolt on 20-25hp which is hard to find and maybe you could produce more air then gas ect...... but I guess then it would start becoming a direct injected X

[XstreamVking]

That's good thinking. Sounds intriguing to me. I dunno the volume of air that passes thru the pump at 6k r's. Some volume at pressures figures are needed. Sons an engineer, he can calculate it....Compressor needed may be too big and 12 volts is not very efficient. If nothing else a 12v compressor as a "get home" kit would be nice. Just for lower speed use.

[Tango]

My thought process is that anything electrical pumpwise would eventually fail too, due to vibration or corrosion. For racing, my application... I would rather use a composite high pressure cylinder similar to the ones I use for Nitrous Oxide and then have a regulated solenoid for air being injected into the motor. This reduces the "moving parts" needed to a proven solenoid system and a variable rate controller.

[flabum1017]

Get rid of the air compressor and hook up a nitrous bottle :D:D:leaving:

[flabum1017]

It's not a whole lot of volume, I wonder how far you can get on a couple scuba tanks................

[powerabout]

how about a pump big enough so the engine ends up boosted when it injects?

[flabum1017]

how about a pump big enough so the engine ends up boosted when it injects?

The compressor is only used to supply air to the air injectors which is a minute volume at 80 psi. For boost, you will need a much bigger compressor or blower..........

[powerabout]

The compressor is only used to supply air to the air injectors which is a minute volume at 80 psi. For boost, you will need a much bigger compressor or blower..........
sure it would be big but would get over all the issues of boosting a 2 stroke

[XstreamVking]

Little N2O mixed in would give it a kick,,,,,,

[Fishinmymission]

Some thoughts:
The current air compressor appears to produce alot of excess air most of which is dumped by the pressure regulator compared to how much is passing through the air injectors. The air injector are tiny and only open for short period in comparison to the regulator.
Per the design of the atomizers there is a pressure that is optimal for fuel atomization. Slow down the compressor speed and you will get larger variations in air pressure.
The cam and bearing were the weak points especially in the early compressor design. You would need some advanced engineering/modeling to figure out if slowing down vs Less air compression force(smaller piston) would put smaller more stable loads on the compressor cam/bearing.

[Tango]

This is why I feel just using a higher quality, ceramic coated & lighter piston will prevail as the needed measure. Reducing drag, weight, load and wear to the bearings should remedy the majority of causes for the pump failure.

Every other measure would require much engineering and effort to redesign the wheel.

[Fishinmymission]

I agree with you. If you can reduce the weight of piston and the piston is robust enough to never fail it would only benefit the cam and bearing.