I have a 1998 Daihatsu Mira L701 with the 1.0L EJ-DE 3 cylinder.
I swapped out the original cluster with one with a tacho, unsure what car it came from.
At 100 km/h in 5th gear, my tacho is showing around 2,250/2,500 RPM.
Does that sound right, or could the tacho be from a 4 cylinder and therefore reading incorrectly?
What RPM should an EJ-DE be doing at 100 km/h in 5th?
Won’t know till next monday when I get home and can check. It will also depend on your wheel and tire size.
That seems to be a very low rpm reading to me (assuming stock tire size and the deep, 0.70 overdrive in 5th gear). I think it is about half of the actual rpm. I would say it should be around 4K rpm. Just speaking from 60+ years messing with cars, no experience with your car.
That would make sense, if the speedo shown was in miles per hour
Butch, I assumed that the speedometer reads in kmh. So, the speed is 100kmh = 60 mph. Here is a calculation of rpm based on Speed, final drive ratio, tire diameter, and gear ratio. I looked up final gear drive of OP listed car is about 5.5, 5th gear ratio is about 0.7 (overdrive), speed equals 60 mph, and tire diameter is about 20 inches). Using a referenced equation to calculate RPM…
RPM = (Speed x Gear Ratio x final drive ratio x 336)/tire diameter
RPM= (60 x 0.7 x 5.5 x 336)/20
RPM= (77616)/20
RPM= 3,880 rpm
I did this calculation to see if my “gut” reaction was close and it seems it is reasonably close. To check the equation, I tried it on my pickup, a 2013 Frontier. This truck has a 6-speed manual with a 4 liter v6. Final gear ratio is 3.7, 6th gear ratio is 0.77, and tire diameter is 30". At 60 mph the calculated rpm is 2085 and my tach reads 2100 rpm at 60 mph in 6th gear (flat ground), so I believe OP’s vehicle is turning about 4000 rpm.
Tyres are 165/55/r14
My suspicion is that it’s a tacho from a 4 cylinder, maybe I’ll have to do a resistor mod or something.
I don’t believe a resistor will affect it. Most tachs are either direct drive or pulse driven.
I calculate the tire diameter is 21 inches.
Twisted, you could with some calculations figure out an overlay on the tach face to make it read correctly. That is how I would solve the problem.
Tacho is from a 4cyl at 100 kmh mine does 3250rpm
i agree it is too low for the tyre size
The only vehicles I have at my disposal is a neighbor’s Audi A4 and a somewhat newer SEAT of almost exact copy. While doing 50 kmh, both tachs say 2000 rpms, if that’s anything to go by. If yours does anywhere near that, you might not need changing anything. Of course, the VW products are both 6-speeds. But, that only means that their top speeds are higher. My former L601 had a long-legged gearing. But, I think that began in 4th gear.
An electronic tachometer should be accurate, when measuring just one cylinder. If so, it would be rediculous for Daihatsu to produce two different tachometer systems, given especially Daihatsu’s production thrift
Alright, I took the bone stock 1992 Rocky out today. At 60 mph (100 kmh) the tach reads 3200 rpm on flatground in 5th gear. So…
I’ll make it a point to do 100 kmh in 5th gear, today. 3200 revs seems high. But it’ll get confirmed
Doing a hundred in fifth, I got 2300 revs
