e34.535i.sport
11-16-2007, 06:04 PM
I've Been searching around for some time as you may have noticed for an upgrade that will give some noticable increase in acceleration for relatively low cost. Difficult to find? Maybe not.
Upgrade Options:
1. Turbo - Way WAY too expensive for most!
2. Supercharger - See above.
3. Engine Swap - See above.
4. MAF conversion - Relatively cheap at around £250 but mixed opinions on the improvement of acceleration and reliability of the unit. I also don't like the idea of splicing the original wires to make it fit. Tempted to go for this one, but too many if's and but's.
5. EAT Chip - Clearly a positive upgrade for £120 or so. Everyone running one reports a marked improvement in acceleration and power. The only negative i can see is the need to run on higher octane fuel.
And finally,
6. Rear Diff Swap (Higher Ratio) - Now, this is an interesting one which i have researched thoroughly, and according to my calculations the best bang for the buck. I'm confident you could pick up a used Diff for anywhere between £100 and £200, and get it fitted for around £150. The theory behind the swap is with a higher ratio acceleration will improve as the revs at speeds will increase (how much depends on what ratio you go for), but top end will decrease. My car is limited to 147mph, which is a speed i will probably never see living in this oppressive country. However, I would either way sacrifice top speed for more low end acceleration. Gears will be shorter too, but that won't bother me. The only negative point i can find is an apparent reduced mpg on a run.
I Quote from Bruno's Site: "a 3.91LSD diff. from a 525iA installed to replace the stock 3.46LSD in the 535i will give you a mileage loss of about 2/3 mpg on the highway. But it is more than justified by the drastic increase in acceleration."
Now, the way i look at it the chip is the obvious choice due to the small initial outlay but it seems that in the long run the diff swap would work out cheaper. Example: Lets say it costs me £350-£400 for the diff swap total. The EAT would cost £120 to purchase and then an extra 8p per litre for the higher octane juice. an extra 8p per litre equates to an additional 36.4p per gallon, and lets say i'd average about 16mpg (about right for 95% city) doing 12000miles per year - using 750gallons of petrol, that would mean an additional cost of £270 in fuel PER YEAR! I make that £390 in the first year, then £270 the next year and so on and so forth. *And thats not taking into account any increase in fuel prices.
If you look at it closely it seems that the rear diff would be less costly in the long run, and obviously give you a serious increase in acceleration. I am looking at this clearly from an external point of veiw as i have not done the swap yet, and others will be able to shed more light on the situation.
What do you think?
Upgrade Options:
1. Turbo - Way WAY too expensive for most!
2. Supercharger - See above.
3. Engine Swap - See above.
4. MAF conversion - Relatively cheap at around £250 but mixed opinions on the improvement of acceleration and reliability of the unit. I also don't like the idea of splicing the original wires to make it fit. Tempted to go for this one, but too many if's and but's.
5. EAT Chip - Clearly a positive upgrade for £120 or so. Everyone running one reports a marked improvement in acceleration and power. The only negative i can see is the need to run on higher octane fuel.
And finally,
6. Rear Diff Swap (Higher Ratio) - Now, this is an interesting one which i have researched thoroughly, and according to my calculations the best bang for the buck. I'm confident you could pick up a used Diff for anywhere between £100 and £200, and get it fitted for around £150. The theory behind the swap is with a higher ratio acceleration will improve as the revs at speeds will increase (how much depends on what ratio you go for), but top end will decrease. My car is limited to 147mph, which is a speed i will probably never see living in this oppressive country. However, I would either way sacrifice top speed for more low end acceleration. Gears will be shorter too, but that won't bother me. The only negative point i can find is an apparent reduced mpg on a run.
I Quote from Bruno's Site: "a 3.91LSD diff. from a 525iA installed to replace the stock 3.46LSD in the 535i will give you a mileage loss of about 2/3 mpg on the highway. But it is more than justified by the drastic increase in acceleration."
Now, the way i look at it the chip is the obvious choice due to the small initial outlay but it seems that in the long run the diff swap would work out cheaper. Example: Lets say it costs me £350-£400 for the diff swap total. The EAT would cost £120 to purchase and then an extra 8p per litre for the higher octane juice. an extra 8p per litre equates to an additional 36.4p per gallon, and lets say i'd average about 16mpg (about right for 95% city) doing 12000miles per year - using 750gallons of petrol, that would mean an additional cost of £270 in fuel PER YEAR! I make that £390 in the first year, then £270 the next year and so on and so forth. *And thats not taking into account any increase in fuel prices.
If you look at it closely it seems that the rear diff would be less costly in the long run, and obviously give you a serious increase in acceleration. I am looking at this clearly from an external point of veiw as i have not done the swap yet, and others will be able to shed more light on the situation.
What do you think?