tntsuperjet
Tntperformance-engineering.com
- Location
- Georgetown ca
I have scene this go round and round and people say I don't want that it's a race engine I'm a free ride guy.
Race engines are tuned to get the most power from what ever power plant you choose to start with so a free ride or freestyle engine needs to be more low end orientated.
News flash. Nothing could be further from the truth. ( from here on FS and FR will mean same.
What a free ride boats need is the most possible power without all the tuning headaches of a full race built motor.
They dont need more bottom more hit or even more tq.
Race motor is built to have te most tq and hp and rev as high as possible.
Now I can turn the most radical race motor into a stunning free ride motor without changing anything in port design shape or timing.
Turning a race motor into a free ride motor is all in setup, race motor full weight crank for best rpm, free ride lighten the crank and lightest possible flywheel, longer tune dimension pipe and shorter prop. Abra cadabra your race motor is now a freeride motor.
You say you want a pump gas free ride vs a race gas.
Now we have to change some engine design as the cyl pressures are to high and detonation will be a problem so we have to detune the engine some to lower cyl pressure so we can control fuel burn and reduce detonation.
You will find a lot of motors built for free ride that have 200 deg exhaust ports.
To put that into perspective of how high 200 deg really is.
Some of the best high reving 2 strokes revved 14,000 rpm with 205 deg exh ports. So another words that's road race port timing for extremely high rpm.
Now water craft have there hand stuck in the cookie jar with wet pipes and people are finding that high port timing they rev higher and it's become more common to have ports that high in watercraft. There tricking te pipe by allowing more hot gasses to escape and it shortens the tune length of the pipe
I can tell you my engines do not have exh ports over 197 deg at the highest and my super jet turns 8050rpm and hits hard enough to get huge air off the smallest of wakes with Solas k prop 82mm nozzle and stock 144pump stock intake in the hull no stuffer.
My rpm come from pipe design and setup
So now for bottom. Some think that if they pull the throttle 1/4 that's low end power some think low end give them back flip ability.
A motor with a lot of low end will hit hard pulling throttle quickly to 1/4 throttle from idle, as low ports will trap pressure with the slightest increase in ingested volume. Taller ported motor will need more intake volume to trap equally with taller ports as the higher ports will allow for more volume to escape through the exhaust port there for require more vomume to be ingested into the motor to get the same response.
That being said the motor that has the best average hp from 3500-7k will feel the best for free ride.
4000-7500 will feel better for race.
One motor design can accomplish both of those with just basic setup differences, pipe, prop, timing, head shape and squish. You an also do long rod setup for more low mid tq as longer rod will increase piston TDC dwell time
Race engines are tuned to get the most power from what ever power plant you choose to start with so a free ride or freestyle engine needs to be more low end orientated.
News flash. Nothing could be further from the truth. ( from here on FS and FR will mean same.
What a free ride boats need is the most possible power without all the tuning headaches of a full race built motor.
They dont need more bottom more hit or even more tq.
Race motor is built to have te most tq and hp and rev as high as possible.
Now I can turn the most radical race motor into a stunning free ride motor without changing anything in port design shape or timing.
Turning a race motor into a free ride motor is all in setup, race motor full weight crank for best rpm, free ride lighten the crank and lightest possible flywheel, longer tune dimension pipe and shorter prop. Abra cadabra your race motor is now a freeride motor.
You say you want a pump gas free ride vs a race gas.
Now we have to change some engine design as the cyl pressures are to high and detonation will be a problem so we have to detune the engine some to lower cyl pressure so we can control fuel burn and reduce detonation.
You will find a lot of motors built for free ride that have 200 deg exhaust ports.
To put that into perspective of how high 200 deg really is.
Some of the best high reving 2 strokes revved 14,000 rpm with 205 deg exh ports. So another words that's road race port timing for extremely high rpm.
Now water craft have there hand stuck in the cookie jar with wet pipes and people are finding that high port timing they rev higher and it's become more common to have ports that high in watercraft. There tricking te pipe by allowing more hot gasses to escape and it shortens the tune length of the pipe
I can tell you my engines do not have exh ports over 197 deg at the highest and my super jet turns 8050rpm and hits hard enough to get huge air off the smallest of wakes with Solas k prop 82mm nozzle and stock 144pump stock intake in the hull no stuffer.
My rpm come from pipe design and setup
So now for bottom. Some think that if they pull the throttle 1/4 that's low end power some think low end give them back flip ability.
A motor with a lot of low end will hit hard pulling throttle quickly to 1/4 throttle from idle, as low ports will trap pressure with the slightest increase in ingested volume. Taller ported motor will need more intake volume to trap equally with taller ports as the higher ports will allow for more volume to escape through the exhaust port there for require more vomume to be ingested into the motor to get the same response.
That being said the motor that has the best average hp from 3500-7k will feel the best for free ride.
4000-7500 will feel better for race.
One motor design can accomplish both of those with just basic setup differences, pipe, prop, timing, head shape and squish. You an also do long rod setup for more low mid tq as longer rod will increase piston TDC dwell time
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