I was searching the net this morning looking for more information about up tuning a TR-1 engine and this thread came up in my duck duck search… I have been exchanging emails with RIVA about their tunes, what RIVA is doing is increasing the stochiomatic characteristics of these engines by reducing the load by using an impeller with a lower pitch and then increasing the rev limiter to 8300 to be able to move more air. Which is one way to increase air flow ergo burn more fuel and make more power without doing anything mechanical to the engines.
I have zero desire to raise the rpm limit on my engines, especially when I know that more stochiomatic flow is attainable another way that has greater potential power wise and will be more efficient. I get why RIVA sells their tuners this way, its plug and play.
@brian86992, if you want more low end pulling power you may want to talk to Leading Edge impellers or Impros about a lower pitch impeller, better yet, a twin screw impeller with lower pitch. You will lose some top speed but your waking ability will be much better, or read on for better results than just a tune.
A little more info here, I could be wrong on this but I’m pretty sure this info is correct. The family of Yamaha three cylinder engines are the YXZ-a 1000cc mainly a street bike engine with the same cams that come in the TR-1 engines. The Genesis a 998cc turbo charged snowmobile engine 172hp, and the Viper a 1049cc engine that is used in the Yamaha Wolverine Side by Side and their snowmobiles. What is pertinent, and what I am 100% sure of, is that the TR-1 is the marine variant of the Viper with the YXZ cams, I’m pretty sure the TR-1 uses these cams for emissions reasons, low overlap, lift and duration keep emissions lower than the Viper cams which have more lift, duration, and overlap.
Note: The TR-1 has an open loop fuel injection system, as does the rest of the Yamaha water craft engines.
Brian Crower makes cams that will work in the TR-1. But, the BC stage 2 cam 0951 is not a drop in cam for the TR-1 engine. Brian put me in contact with an Australian fellow who modded a TR-1 engine for use in a mini jet, which looks and sounds pretty trick, in addition to the BC stage 2 cams he put in higher compression pistons. The short version is that the BC stage 2 cams are identical between intake and exhaust, but the cams need to be flipped on the engine, the casting ring needs to be machined for the cam position sensor, and the intake cam gear has to be slotted to get it timed correctly. From an engine mod perspective this is a pretty minor thing to do. I have already spoken with a gunsmith machinist that is a hot rodder enthusiast and he said he could make these mods and time the cam gears with ease.
These cams by themselves will increase seal level performance of the TR-1 by 15% at sea level, no tunes, air box mods etc… if one were to add some fuel then one can expect 25% more power at sea level and thus get the most out of these cams. The BC stage 2 cams accomplish this by; using a steeper ramp angle to open the valves faster, more lift, more duration, 8* more overlap (aka clean out) and faster closing ramps, all of these attributes increase the stochiomatic ability of the engine, across the rpm range, meaning you have increased the efficiency of the air pump (engine) and can therefore burn more fuel to make more power across the rpm range of the engine. I am mainly looking for mid range power to be able to carry MORE pitch on the impeller at high density altitudes to keep the revs down and efficiency as high as possible at best cruise speed and rpm.
Making mechanical modifications in an engine like this is the best way to get more performance out of them, especially when one knows that there are other variants in much higher states of tune than where I want to go with this project.
In my emails back and forth with RIVA I have learned the following, RIVA does have a tune for the TR-1 engine as mentioned in
@brian86992 original post by decreasing pitch on the impeller and raising the rev limiter by 300 rpm. RIVA also has a Viper engine map which is promising. RIVA also makes a 02 sensor kit for monitoring the AFR (air fuel ratio) and is also a data logger. Using this device one can record AFR’s while running, and then send that file to RIVA and they will feather the tune for your engine. I would love to have a real time auto tune wherein the tuner is goes in between the oem injector plug from the ecu and the injector, and uses the 02 sensor in realtime to adjust fueling to get the desired AFR, this is how your gasoline powered car works, Dobek used to make an auto tune but is no longer Dobek, is some other name, and they do the same thing that RIVA does with the 02 sensor. Dynojet makes a auto tuner that works with the Viper and YXZ engines, but, that requires the YXZ / Viper ECU to be used as well as the plugs, I should note here that both the YXZ and the Viper used a closed loop fuel injection system to the best of my knowledge. I am not willing to give up my no wake / cruise assist by using a different ecu, I‘m not sure that is the case, I don’t know how the no wake / cruise assist is activated, just stating that fact.
So at the moment, it appears that RIVA is the only game in town for the TR-1, unless the tuner the Australian guy uses can be used. Next on the list is to contact him again and find out how he increased the fuel in his engine project and whether or not that system is a closed loop or not.
This is a project I’m researching for next winter, when my YES warranty is almost completely used up.
