| Author | Message | ||
     Ft_bstrd |
Motus has moved onto the next level in production. The next step will be to build the EPA compliance "production" units. Testing and development is complete. They have decided NOT to go GDI and instead go with a traditional FI system. This decision comes as a result of dealers and tuners wanting a system that they are more comfortable with. Motus plans to be back in Daytona in March where pricing will be announced. | ||
| Natexlh1000 |
No direct injection? Wouldn't that force them to use a catalytic converter and cost them power? | ||
| Ft_bstrd |
Don't know. Possibly. | ||
| Xl1200r |
The XBs don't use DI and didn't need a cat, so they could be okay depending on how effecient the runners and chambers are. | ||
| Hybridmomentspass |
XL - Agreed. Many many FI bikes out there with no cats on them including both of my buells | ||
| Jaimec |
Actually, using a catalytic converter would mean they wouldn't have to run the engine so lean and COULD mean MORE power (and cooler running, too) without exceeding allowable emissions. | ||
| Buellkowski |
I am sorry to hear about their dropping GDI. How much of an hp drop do you think that will translate into? In it's current configuration as a pushrod-driven two-valver, could the power loss be 20% over the 160 hp GDI? | ||
| Hybridmomentspass |
Are you asking 20% less hp cause of using standard EFI versus GDI? Thats a staggering amount, didnt realize that GDI was that efficient, not knowing much of direct injection. | ||
| Xl1200r |
I think 20% is probably a gross overestimate. When GM's high-feature 3.6 V6 got GDI, it was a big improvement (about 15%) in power, but that engine also got a 1.2:1 higher compression ratio which helped a lot, and I believe better cam profiles as well some other updates. We might see a 10% drop, maybe, on the MOTUS. I'm kind of annoyed that they bailed on it because dealers and tuners wanted something they were comfortable with. This kind of thinking doesn't belong on a forward-thinking company. If everyone were like this we'd still be running carbs. | ||
| Froggy |
That was my thoughts exactly, I wonder if it is a cop-out due to other unforeseen issues in development? | ||
| Brumbear |
It may be a cost reduction thing and sold as a tunner thing though. I think the way things are going for a bike to sell has to be mid teens and this may have a bit to do with it in the long run but thats just my opinion. | ||
| Ulynut |
Even a 20% reduction in HP would still be around 128 HP. Not too shabby. Anyone know how much torque this monster will put out? We all know torque is what gets you out of the corners and down the road, right? | ||
| Ft_bstrd |
I was told when asked that there was actually an improvement in performance. My guess is that the trade off is efficiency. | ||
| Darth_villar |
Direct injection is more efficient and more powerful. There is really no legitimate downside that I know of. Cost and complexity may be higher than regular FI, but DI is definitely the near future of ICE and it is a large disappointment to see them drop it. DI allows super lean mixtures to burn without detonation, because the gas stream is directed near the spark plug/plugs, and it is only injected the instant before detonation. | ||
| Jaimec |
DI does not allow the higher redlines used by most modern high performance racing engines. THERE'S your downside. | ||
| Crackhead |
DI does not yet allow the higher redlines used by most modern high performance racing engines. There I fixed it for you. Xl1200r +1 If their logic, was applied to EBR, the rear wheel would still have a hub.} | ||
| Guell |
As a sport toured I care about it being more reliable than something more advanced. If its a more known fi system I'm more likely to be able to find someone who can fix it, or even fix it myself. | ||
| Darth_villar |
Forgive me for not being clear. I see no downsides particularly for the Motus. I am aware of the current rpm limitations of DI. | ||
| Hughlysses |
I'm sorry to hear Motus dropped GDI. It seemed like a really cool feature. It seems like GDI would have worked really well on our air-cooled Buell engines. They're (relatively) low RPM, and GDI might have allowed significantly higher compression and power. Doubt we'll see the Mothership trying it any time soon. | ||
| Syonyk |
If its a more known fi system I'm more likely to be able to find someone who can fix it, or even fix it myself. When was the last time you had a fuel injection system fail? Modern automotive-grade fuel systems and ignition systems are *insanely* reliable. I know many of you grew up with carbs & points & "well, I can fix it myself" - that's fine, when you *have to* fix it regularly. Modern cars *easily* do 100k miles on factory spark plugs, with zero fuel injection issues. Oh, and they get really good fuel economy doing it, and 200hp is "sort of acceptable" for a family sedan. I'd absolutely love to be able to do 100k miles on a motorcycle doing nothing to the engine other than oil changes and putting fuel in. 12k mile engine rotations for valve checks are unheard of in the automotive realm anymore. I was looking forward to the Motus bike, mostly for the GDI. More torque, more power, better fuel economy, cleaner burning. I'm less interested now. | ||
| Ft_bstrd |
Motus has a different model that played into the decision to use FI instead of GRID. Part of the plan is to sell the engine as a crate motor independent of the motorcycle. The intent for the initial run of bikes is around 300. Their target is the sale of 1000 engines including bikes produced. From a tuning standpoint, the market drove a FI switch. Buyers of crate motors gave feed back they they would prefer FI. The two test mules provided data acquisition for both systems. One had FI. One had GDI. (Message edited by ft bstrd on February 16, 2012) | ||
| Hootowl |
"12k mile engine rotations for valve checks are unheard of in the automotive realm anymore." True. But they make far less power per CC than a MC engine does. You can get away with self adjusting hydraulic lifters in a car (or a tuber!) but for a motor that spins over 10K, it's just not going to work. Too heavy. The spring pressure necessary to control the valve/lifter and prevent float would tulip the valve. | ||
| Ft_bstrd |
There are as few GRID tuners currently as there were FI tuner in the early days of FI implementation. It will catch on, but MC technology seems to be a late adopter of new fueling technology. There are still brand new carbed bike available on the market today. | ||
| Jaimec |
Geez, even Royal Enfield has upgraded to FI! | ||
| Natexlh1000 |
Direct injection bikes are already out there: http://www.dieselbike.net/yanmar/yanmar.htm  | ||
| Buellkowski |
How much horsepower could a 1.7 L, FI, normally-aspirated, two valve, non-VVT, pushrod engine reasonably make? I threw out the 20% reduced power figure because I personally don't see how the Motus engine can make that much more power than Honda's ST1300, which is rated under 120 hp.  I attributed (perhaps incorrectly) the Motus' 160 hp performance claim to its GDI, and I supposed that 130 hp or so was the best a FI engine in Motus' configuration could make. | ||
| Ft_bstrd |
I wonder if the RPMs could be increased enough to eliminate some of the HP loss from switching to FI. I don't know that you can compare one V-four to another. What about Aprilia's V-four? | ||
| Buellkowski |
The current V-Max engine is the closest analogous engine I can find, but it's DOHC. Around 175 hp. | ||
| Jaimec |
If you want a V-Four that's positioned in the bike the same way as the Motus, you're looking at the engine in the Honda ST1300. | ||
| Hughlysses |
Wouldn't another useful comparison be the LS3 Chevy V-8, which the Motus engine is supposedly based on? That engine is 6.2L and makes 430 HP, which works out to about 69 HP/liter. If the Motus engine achieves similar performance, 1.7L x 69 HP/liter works out to only about 120 HP. |
