Removing speed limiter

[ChequeredRoof]

I know, I know, much has been said about the stupidity of trying to remove the 93mph speed limiter, but my reason is slightly different...

I have an ex-RAF 1989 Ford Transit County 4x4 in the UK into which I have squeezed a US-spec 4.0 SOHC (and A5R55E transmission) from a 2004 Ranger.

Here's the engine:

That's a Mustang 4.6L radiator in the front.... but anyway, my problem is that with the axle ratios I am running, the PCM thinks the vehicle is doing 90mph when actually it is doing 60mph. This is very frustrating, as I used to be able to cruise at 75mph with my old 2.0L engine. Now I can only ever reach 60mph (although I do get there very quickly!!).

The PCM has already been professionally re-programmed to believe that it has the closest Ranger tire sizes and transmission ratios to match what I have, but it still reckons I'm doing 1.5 times (yes, 1.5 times) the speed I am actually doing. I have been told that it is not possible to "tweak" the PCM any more than this; I am apparently at the limit of the settings.

I have tried using two different box of tricks (one from Ford Performance) to alter the speed signal to try and "fool" the PCM into thinking the speed is lower, but all this does is throw the transmission (A5R55E) in a fit. I have been told this is because the difference between the output shaft speed and the road speed is too far outside the normal limits of what it expects.

Other than change the axle ratios, the only route left is to try and remove the speed limiter. My tyres are rated to 95mph, but actually I would be delighted just to get to 70 or even 75. I am pulling 3,049rpm at 60mph, and would be doing 4,065rpm at 80mph. That's plenty enough for me.

So, has anyone managed to re-programme the PCM to remove or re-set the speed limiter? With respect, I am keen to hear from anyone who has actually, definitely, genuinely managed to do it successfully. I know there have been plenty of suggestions in other posts of various reprogrammers I could try, but I don't want to spend good money on this unless I KNOW that it's going to be possible.

Thanks for reading this far, and I trust what I have written makes sense. By the way, I could never have done my engine swap without advice from the Ranger Station. A top resource.

 

[adsm08]

It's not possible to tweak it any farther via Ford's scanners. A tuner can be used to reprogram the computer an completely remove the limiter.

The other option is to re-gear.

 

[ChequeredRoof]

It's not possible to tweak it any farther via Ford's scanners. A tuner can be used to reprogram the computer an completely remove the limiter.

The other option is to re-gear.

Thank you adsm08. I understand I've gone as far as I can with Ford's scanners.

I'm not keen to re-gear.

I am guessing you are suggesting something like the Superchips Flashpaq 1815 or 1865. I have researched these, and the bottom line is that, although it looks as if it might be possible to raise the speed limiter (and adjust individual shift points which would be good), it is almost impossible to get a definite yes or no as to if it will work (because they always say "features available dependant on variant" or words to that effect). That is why I am keen to know if someone has actually got it to work, not just thinks that it might. Has anyone out there tried and succeeded? I don't want to go spending $280 for this one feature and find it isn't actually available or doesn't work.

 

[adsm08]

I am thinking more of a custom tune.

 

[ChequeredRoof]

I am thinking more of a custom tune.

I would dearly love to find someone here prepared to help me, but I have had no luck finding a custom tuner here in the UK who is prepared or equipped to work on the 4.0 SOHC which was never a factory option in any vehicle in this country.

Is it a stupid idea to think that I might be able to sort this particular problem with something like a Superchips Flashpaq?

 

[adsm08]

It may work, but since I have not dealt with one first hand I can't tell you for sure.

 

[ChequeredRoof]

Does anyone have any first-hand experience with the Superchips Flashpaq 1815 or 1865 (or similar) and a 2004/5 Ranger 4.0 SOHC with A5R55E? Can it remove the speed limiter? Can I re-set shift points? Any alternative suggestions? Many thanks.

 

[Maritime Storm]

"I am pulling 3,049rpm at 60mph, and would be doing 4,065rpm at 80mph." Lokking at those RPMs on a 4.0L SOHC, I'd be re-gearing. Most Rangers are geared turn 2100-2500RPM at 60mph.

 

[alwaysFlOoReD]

I'd like to know too. Please update if you find info elsewhere.
Subscribed.
Good luck,

Richard

 

[ChequeredRoof]

"I am pulling 3,049rpm at 60mph, and would be doing 4,065rpm at 80mph." Lokking at those RPMs on a 4.0L SOHC, I'd be re-gearing. Most Rangers are geared turn 2100-2500RPM at 60mph.

Thanks, I know the revs are high. Re-gearing with this vehicle is more complicated than it should be. The best ratio available for the Ford Transit twin-wheel rear axle is 4.63 (I currently have 5.83). The front axle is Dana 44 (Bronco), and the closest match is 4.78 (Dana ring and pinion set 706017-12X), but these no longer appear to be available, and I have failed to find anyone selling them. With the 4.63 rear, I would be pulling 2,421rpm at 60mph. Much better, if only it was achievable.

For those concerned that the front and rear ratios don't match exactly, the factory version (that I have) has a 1.02% "lead ratio" on the front (meaning the front "pulls" slightly), which is fine as the 4WD is selectable and for off-road use (loose surfaces) only. The 4.63 / 4.78 combination would give a 3.14% "lead", which although bigger (11.3 degrees per revolution compared to 3.67) is still within the "maximum 5% difference" which is recommended for tractors!

Thanks for your interest Richard. I will update here if I find the speed limiter answer elsewhere.