>From the insight shop manual, the primary reduction is direct (1:1), and the final reduction is is 3.208.
Certainly there is some room for error--it's hard to get more than 2 digits of significance from the dash instruments. My two data points were 3000 RPM at 70 in 4th, and 3800 RPM at 70 in 3rd. Using the 4th gear figure and the two gear ratios from the manual, it would predict 3837 RPM for 3rd gear, which matches the observation. Being new at this, I used this relative method rather than go through the entire drive train. However, I'd be happy to have someone take a different approach to this calculation. I seem to recall Wayland talking about "tall" gears on the Insight--perhaps that is what he was trying to say. In any case, the relative calculation puts the redline of 6000 RPM at 69 mph, so we're only a bit apart here. Gary > From: Seth [EMAIL PROTECTED] > What's the final drive ratio? The reason I ask is that it is uncommon > for cars to exceed 65mph in 2nd gear. Which means that the insight > transmission is a bit unusual in that way, or perhaps the calculations > are off by 10-20%? I only ask because 70mph seems pretty unusual for 6126rpm. > Seth Gary Graunke wrote: > > > From: "Thomas Shay" <[EMAIL PROTECTED]> > > > Subject: Re: shaft coupler material > > > Is it necessary to machine a coupling from scratch? It must be possible to > find > > something that fits the motor splines. Surely a motor doesn't exist that > nothing > > fits that the motor could drive. The center cut from a clutch disk could > > serve as the transmission end of the coupling. It seems two coupling > halves could > > made and joined. > I strongly suspect that there is a European auto that fits the motor -- an > Opel, if I recall what Victor said. > (But then I'm probably having trouble remembering the material type from > this morning!). > > We also considered bolting two halves together as a backup plan, but our > first choice was to have a single piece. > > > Can the Insight transmission tolerate being driven at 10,000 rpm? > > While it certainly is good insurance to keep the clutch for this very > reason, I did calculate the RPM at various speeds, using an observation that > the Insight goes 70 mph at about 3000 RPM in 4th gear. Using the gear ratios > from the Honda Insight shop manual (3.461 for first, 1.75 for second, 1.096 > for third, 0.857 for fourth, and 0.71 for fifth), I calculated the following > RPM for various speeds. > > The numbers for second gear were > MPH RPM > 70 6126 > 80 7001 > 90 7876 > 100 8751 > 110 9627 > 120 10502 > > Since I don't plan on going that fast (and we think the top speed due to > aero drag is about 110 for the 54 KW I'll get from 240V anyway), 2nd should > be ok. The redline for the Insight ICE is 6000 RPM, so I expect the > transmission will be ok at 70. Of course, lower RPM's would be easier on > both the motor and tranmission. > The torque is still maximal with the AC drive at 240V until I get to 4200 > RPM, somewhere over 45 mph, but should be ample for normal driving even > above that. > > I also recall Sheer's post which indicates that he obtained somewhat higher > efficiency on his trip from Portland to Seattle using 3rd and 4th gears. I'd > like to check this out before going to fixed gears. The efficiency gain > might itself justify leaving the clutch for frequent highway drivers. In any > case, 2nd should be just fine around town. > > Gary > > > Tom Shay > > > From: "Gary Graunke" <[EMAIL PROTECTED]> > > To: <[EMAIL PROTECTED]> > > Sent: Wednesday, October 02, 2002 2:55 PM > > Subject: shaft coupler material > > > > What material is best for a direct drive coupler? I'm having a coupler > made > > > that connects an A/C driver motor (max RPM 10,000) to a Honda Insight > > > transmission shaft. The piece will be machined with male spline on the > motor > > > end, and a female spine on the tranmission end. The max torque is 92 > ft-lbs.
