Has anyone attempted to put the 6 speed F40 tranny on the Duke? Wondering if it is possible and if there would be advantages. The Indy has a 4 speed and was definitely designed for 55 mph travel on the highway. Wondering what the standard 5 speed and F40 6 speed would do...
The F23 uses approx 24,000 PPM VSS out put and the F40 60,000 compared to the Fiero 4,000 so with either the F23 or the F40 some thing would be required to have an operational speedo and signal to send from the speedo to the Fiero ECM. Dan
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DARN Cars now open with Over 30 years wiring experience between cars and trade as an avionics technician in both Canadian Air Force and civilian aviation. Over 25 years experience building and modifying cars. Over 10 years of full Fiero engine swaps and harnesses building and still going.
The F23 uses approx 24,000 PPM VSS out put and the F40 60,000 compared to the Fiero 4,000 so with either the F23 or the F40 some thing would be required to have an operational speedo and signal to send from the speedo to the Fiero ECM. Dan
I have thought of it, but its way down the list. My 88 2.5/125C Fiero is glutless... with the F40 at least it would be more fun to drive while being gutless.
Can the Dakota Digital Speedo converter be made to work or does that only convert the VSS siganal to a Gauge?
Either way, I assume the goal would be for MPG and I can tell you just because your RPM's drop that doesn't mean you will get better MPG If the duke can't turn 6th gear and you are running 60-70% throttle just to get up a hill .
The F23 would be cheaper and easier to install, than the F40. And it would probably be more fun to drive (at least, the MG3 RPO version), behind the duke.
The Duke can probably spin 6th gear in the F40 without any problems on flat land, just like it can with 5th on the Isuzu, but if you hit uphill with most any manual trans in top gear, with a Duke, you're proabably going to have to downshift to do it. I certainly had to do it with the 6 speed in the Chevy Cruze Eco. Gets great MPG, but that little 1.4L turbo doesn't have a lot of power.
...if you hit uphill with most any manual trans in top gear, with a Duke, you're proabably going to have to downshift to do it.
I'm not trying to be rude (honest), but how unusual is that? I imagine with a lot of engines (most engines?), you need to downshift from the highest gear when climbing a hill of any appreciable grade.
EDIT - Sorry, I realize now that you were responding to the previous post (copied below).
I don't know how many low to medium HP engines are going to be able to race up a steep hill in an overdrive gear.
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Originally posted by 1fast2m4:
Either way, I assume the goal would be for MPG and I can tell you just because your RPM's drop that doesn't mean you will get better MPG If the duke can't turn 6th gear and you are running 60-70% throttle just to get up a hill .
[This message has been edited by Patrick (edited 10-23-2013).]
Can the Dakota Digital Speedo converter be made to work or does that only convert the VSS siganal to a Gauge?
For this application, you would want to install the Dakota digital converter between the VSS and the 203 connector and send the buffered signal to the speedo. Then the stock speedo buffer will feed the stock ecm in the stock manner.
On a '7730, you can feed the ECM with the VSS then set the divisor to 7 or 8 and use the 2000PPM output from the ECM to feed the speedo after converting it back to an analog signal. No Dakota Digital unit necessary. The circuit is simple and I think is on Darth's site.
60,000 / 4,000 = 15. Ideally using the 2000ppm output the divisor should be 7.5 but it only supports no division or 6-11...hence your choices are 7 or 8. 8 makes your speedo read slow, 7 makes it read faster than you are going. The error is only 6.67% either way. If you are running wheels with a non-stock diameter, you may end up being more accurate than before with the correct 7 or 8 setting.
BUT!
Ask the original 2.8 + F40 prototype owner, I could barely accelerate @ 65mph in 6th gear...don't expect much with a duke. If you normally drive 80, you should be ok. That said, I only drove it as a 2.8 before yanking it to build my 3.400 roller cam block car. No problems with accelerating in 6th gear with the 3.400...
[This message has been edited by lou_dias (edited 10-24-2013).]
My LS4/F40 car shows about 60lb-ft is needed to keep the car rolling at a steady 65 mph in 6th gear (with 245/50/16 rear tires) at 1941 RPM
The duke is a low rpm engine with a torque peak of about 135lb-ft around 2800 rpm. The key will be if it can pull 6th gear w/o enabling PE mode. It would be a cruise only gear as accelleration would be very poor... like when I get down to 1200 RPM in 6th... it will pull along at that speed all day, but if you want to speed up, you need to drop down a couple of gears.
I've only driven a manual duke a few times. The last time I found that I needed to down shift out of 5th if the speed dropped below 50 mph, even on flat land.