Today I drove 450 miles for an 2 hour meeting 225 miles each way and I was amazed at my gas mileage. I averaged about 81 MPH. I use to average about 23-24. However after cleaning the throttle body, speed sensors and making adjustments to my idle and such much better

 

Now on to intake porting , K & N oil / air filter and exhaust valve modification

Is your results with a Andy Bracket

 

I don't believe in the K&N products. I know that's typically a sensitive subject.

 

I tried it and power was the same and milage was worse. Have one for sale if anyone is looking for them. Already have the Andy bracket and the exhaust manifolds, my second pair, are going out for ceramic coating along with the heat shield

 

Just imagine what a 5th gear would do? That's what Jaguar thought when they put the 5HP24 in the X308. But it was a disaster.

The Andy bracket helps!

 

Hi Phil,

One thing to be aware of is that the onboard computer only estimates fuel economy based on various sensor inputs, it doesn't actually measure fuel economy.

On my '93 XJ40, comparing the onboard computer with careful fuel usage tests over a 60-mile test circuit showed the computer typically reported 1 to 2 miles per gallon lower than actual measured mpg.

After installing the Andy bracket, the difference increased, so that while the actual measured fuel economy improved by about 2 mpg, the onboard computer reported usage that was up to 3 mpg less. I suspect the fuel usage algorithm cannot take into account the advanced ignition timing of the Andy bracket.

It would be interesting to hear Andy's take on this subject.

Cheers,

Don

 

My take is that a accurate calculation would require a fuel flow meter with the available distance variable

In this case they are probably adding the pulse injector widths with a ideal injector flowrate and a ideal fuel pressure which does increase in pressure and flowrate with higher RPMs

 

Theoretically, all that would be required would be the odometer and fuel level sender signals. But obviously, the fuel level sender spends most of its time floating up and down when the car is in motion (thus the damper circuit for the gauge). Add to this the facts that the shape of the fuel tank and arc of the sender arm mean the sender reading versus fuel level is not exactly linear.

 

It would be linear with a short between sample time before and after which would be the case of a near instantaneous changing MPG reading

But then the slosh error which I don't think they can overcome even with averaging

 

Another variable to consider is the tyre profile as the speed/distance input comes from the LH rear wheel ABS sensor and does not account for tyre diameter/circumference.

Cheers,
Jeff.

 

You must have been LATE for that meeting. Or getting back home quickly to act as if it never happened.

OR... you are in a Jaguar!!

 

On the same stretch had it moving just over 120 and it started to float on me so had to shut it down. It just wanted to run faster and faster. I love my car and although I have been offered of 32K she will be by my side until I take that last drive.

 

Are you claiming that someone offered you $32,000?

 

Sure did. He had been trying to buy it for a few years. He said he had one very similar and wanted another one. When he first started asking, it was in the low 20s, and I told him there are many out there that you could get for so much lower. Why mine? He said because he knew I had been taking care of it for years and if there was something wrong with I would have fixed it. Not to mention it is in very good shape.
He also had money to spend.....a lot of money.