The next Mod to the XR8 - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

BOF · 05-03-2002, 00:43

I've got quotes and am going to go ahead with the next mod that Dollar for Dollar I reckon is going to be very hard to beat!

I'm getting rid of the 3.27:1 BTR and getting a .................

a 3.91:1 instead, i know she will use a little for fuel and rev a little higher but I reckon it must knock off half a second over the 1/4?? anyone have any idea??, whatever it does I reckon it's going to jump a little harder off the line when it's done.

Anyone know about speedo recalibration??

Thanks

EDXR8 · 05-03-2002, 01:13

I just did this mod to my friends EB XR8. Fuel economy decreased only slightly, but it was much more fun to drive. Using a performance meter it only measuerd a 0.4 second decrease in 1/4 mile times. To correct the spedo, a unit goes behind the dash to change the input signal.

BOF · 05-03-2002, 01:22

Any idea of the cost of this device that goes behind the dash? 0.4 sec is decent enough i think to be happy with, say crossing the line at about 145km/h it equates to about 4 car lengths at the line.

I think it would roughly run a 15.7 or so now so if I can take a half a second off im down to a low 15 which i reckon i would be happy with for a while.

EDXR8 · 05-03-2002, 02:08

All up it is around $1100. About $700 for the diff and $400 for the spedo corrector. If yours is an auto, the 3.9's are the way to go. If it's a manual, I have been told to go for 3.73's.

Venom XR · 05-03-2002, 06:12

Good if you drag the car a lot, not good if you drive long freeway distances though. :s3 Good luck, lets us know your new 1/4 mile times.

EDXR8 · 05-03-2002, 07:15

It's not that bad on the highway. At 120kph it sits on 2750rpm with an auto.

Troutman · 05-03-2002, 19:14

$400 for the speedo corrector? My understanding is that there is a much cheaper part from Ford that does the same job (though I don't think it would be quite as easy to install). Can find out more if needed.

Xyphoid · 05-03-2002, 21:24

Try changing the speedo sender Gear !

It must be a lot cheaper than using a Frequency Divider Circuit to modify the Speedo Frequency that is being sent to the Instrument Cluster from the Speedo Sender !

Check out
http://www4.tpgi.com.au/users/mij/Au...peedoCalc.html

According to the Percentage change in the Diff, at an Actual Speed of 100Kmph, your speedo will read 78.95Kmph.
This is a change of -21.05%

What you will need to do is go for a speedo gear with more teeth than your current one, to try and correct this percentage error.

Unfortunately, I am not sure of what make or Model the car is that you are planning on carrying this out on, so I dunno what Gear you would have in there already.

If you can find out what colour Speedo Gear you have, punch it in the the Standard Speedo Gear on the Webpage, and play with some speedo Gears on the Modified side, to try and reduce the speedo error. Also, if you have changed profile and wheel sizes, punch these in while you are at it, to reduce the total speedo error to the absolute minimum !

As for the speedo gear location,
On the BTR Auto, and the T5, the speedo sender is on the passenger side of the gearbox. (If U want more details, lemme know, and I will get some pics for you !)

Also, some of the Older Model Fords have a Trimpot at the Back of the Instrument Cluster, where you can alter the speedo Percentage error. - I personally have never seen these, but I have been told that there are such beasties out there !

Just some idea's to help you save a little money !

Cheers
Matti

Herrod Motorsport · 05-03-2002, 23:33

As far as the speedo i have had made a different output shaft gear for the speedo drive,costs around $150.00 auto trans can be done in the car but manual must be removed to change the gear.

Homer? · 05-04-2002, 00:02

Let us know how you go with this BOF and who you get to do it, as this is going to be the next mod for the EF. The EF has a 3.08 in it :crazy1:

The dash on Ex-police cars are adjustable. Maybe you can find one to make it easier.