Demystifying performance modifications

[Anonymous]

On my journey tweaking my Zed there was much debate about how these and other peoples modifcations would affect the performance of these vehicles.

I did some desk based work interpolating published BMW figures for various E89s and then extrapolating what other BHPs would do to the numbers.

We then got into a how does torque impact these numbers..

R.E92 suggested actual real world testing and (I think it was him) suggested a 'dragy'..

Following on from less than productive discussions on Zed max speeds and where one could test them I thought I'd at least work on the performance figures at less than max speed.

To address this I've bought a 'draggy'..its a small box that uses a clever combination of onboard sensors and GNSS to act as a dat logger to a very high degree of accuracy..its been cross tested against industrial units with very positive results.

For your £125 you get an Apple type experience..ie small white box, a device with no buttons/ switches and zero instructions..

You download the iOS or Android app to your smartphone, start the app and it finds draggy aassuming you have bluetooth switched on.

Its got an onboard battery that recharges quickly and allows 8 hours use they claim.

I've only played with it for a short period of time..

My first attempts at 0-60 resulted in lots of wheel spin and tramping so will have to read up on how to do launches..

I plan to take it to various meets next year and encourage others to use it to build up a database of real world numbers..

Enjoy..

 

[enuff_zed]

That's interesting, and should certainly balance out the bar bragging a bit.

But if you're doing your tests downhill that's cheatin'!
That drop of a couple of metres will make all the difference y'know. :wink:

 

[Anonymous]

Don't let facts get in the way of prejudice..

I was less than impressed with my expenditure initially as it seemed very non functional..however as you point out its very clever..the flag pops up if it doesn't think the data is kosher for whatever reason..

Trying to find 800m that's flat around where I live (ie a 20 mile radius) is hard work..

I have now identified a road that seems pretty flat and will return to get some better data when track conditions dry out..

Still the profile is quite useful as you can see, in this case how G, road gradient, time all map out

I can tell you that from other runs it seemed to go faster up slight uphill gradients than downhill, for some weird reasons..more data to follow..

 

[enuff_zed]

Don't let facts get in the way of prejudice..

I was less than impressed with my expenditure initially as it seemed very non functional..however as you point out its very clever..the flag pops up if it doesn't think the data is kosher for whatever reason..

Trying to find 800m that's flat around where I live (ie a 20 mile radius) is hard work..

I have now identified a road that seems pretty flat and will return to get some better data when track conditions dry out..

Still the profile is quite useful as you can see, in this case how G, road gradient, time all map out

I can tell you that from other runs it seemed to go faster up slight uphill gradients than downhill, for some weird reasons..more data to follow..

Will it allow you do runs in both directions and average them out?

Just a wild stab, but maybe a slight uphill puts a bit more weight over the driven wheels to aid traction. Just enough to help but not so steep that it slows you down.

 

[enuff_zed]

Does it also measure g-force under braking?
That would be a useful tool for brake mods (up to the point where the tyres let go anyway)

 

[Anonymous]

Don't let facts get in the way of prejudice..

I was less than impressed with my expenditure initially as it seemed very non functional..however as you point out its very clever..the flag pops up if it doesn't think the data is kosher for whatever reason..

Trying to find 800m that's flat around where I live (ie a 20 mile radius) is hard work..

I have now identified a road that seems pretty flat and will return to get some better data when track conditions dry out..

Still the profile is quite useful as you can see, in this case how G, road gradient, time all map out

I can tell you that from other runs it seemed to go faster up slight uphill gradients than downhill, for some weird reasons..more data to follow..

Will it allow you do runs in both directions and average them out?

I don't think it does..but you can just turn around and go the other way and the calculation manually..

 

[Anonymous]

Does it also measure g-force under braking?
That would be a useful tool for brake mods (up to the point where the tyres let go anyway)

Yup most profiles you can want both accleration and de-acceleration o-60 0-100 1/8 mile 1/4 mile etc etc

 

[enuff_zed]

Does it also measure g-force under braking?
That would be a useful tool for brake mods (up to the point where the tyres let go anyway)

Yup most profiles you can want both accleration and de-acceleration o-60 0-100 1/8 mile 1/4 mile etc etc

Post up the g figure when you get to the bottom of Beachy Head then.
Well, ask someone to do it for you.

 

[Anonymous]

Does it also measure g-force under braking?
That would be a useful tool for brake mods (up to the point where the tyres let go anyway)

Yup most profiles you can want both accleration and de-acceleration o-60 0-100 1/8 mile 1/4 mile etc etc

Post up the g figure when you get to the bottom of Beachy Head then.
Well, ask someone to do it for you.

I'm sure someone will complain that the attitude of the car when it hit the ground was incorrect..

 

[buzyg]

Don't let facts get in the way of prejudice..

I was less than impressed with my expenditure initially as it seemed very non functional..however as you point out its very clever..the flag pops up if it doesn't think the data is kosher for whatever reason..

Trying to find 800m that's flat around where I live (ie a 20 mile radius) is hard work..

I have now identified a road that seems pretty flat and will return to get some better data when track conditions dry out..

Still the profile is quite useful as you can see, in this case how G, road gradient, time all map out

I can tell you that from other runs it seemed to go faster up slight uphill gradients than downhill, for some weird reasons..more data to follow..

Just a wild stab, but maybe a slight uphill puts a bit more weight over the driven wheels to aid traction. Just enough to help but not so steep that it slows you down.

There is very slightly more downward force over the rear wheels at rest, pointing up hill. It is not going to aid traction though. As soon as turning torque is applied the grip is going to be less than going down hill. Think of it as pushing off a wall and please don't ask for a mathematical proof. Pbondar will likely never speak to me again, if we go there. :wink:

 

[enuff_zed]

Don't let facts get in the way of prejudice..

I was less than impressed with my expenditure initially as it seemed very non functional..however as you point out its very clever..the flag pops up if it doesn't think the data is kosher for whatever reason..

Trying to find 800m that's flat around where I live (ie a 20 mile radius) is hard work..

I have now identified a road that seems pretty flat and will return to get some better data when track conditions dry out..

Still the profile is quite useful as you can see, in this case how G, road gradient, time all map out

I can tell you that from other runs it seemed to go faster up slight uphill gradients than downhill, for some weird reasons..more data to follow..

Just a wild stab, but maybe a slight uphill puts a bit more weight over the driven wheels to aid traction. Just enough to help but not so steep that it slows you down.

There is very slightly more downward force over the rear wheels at rest, pointing up hill. It is not going to aid traction though. As soon as turning torque is applied the grip is going to be less than going down hill. Think of it as pushing off a wall and please don't ask for a mathematical proof. Pbondar will likely never speak to me again, if we go there. :wink:

But if by 'go faster' he means it takes fractionally less time to get to 60, then it could well be due to that added force on the back wheels so that they grip instantaneously rather than a teeny bit of slip. I suspect we're only talking very tiny fractions of a second?

 

[buzyg]

Just a wild stab, but maybe a slight uphill puts a bit more weight over the driven wheels to aid traction. Just enough to help but not so steep that it slows you down.

There is very slightly more downward force over the rear wheels at rest, pointing up hill. It is not going to aid traction though. As soon as turning torque is applied the grip is going to be less than going down hill. Think of it as pushing off a wall and please don't ask for a mathematical proof. Pbondar will likely never speak to me again, if we go there. :wink:

But if by 'go faster' he means it takes fractionally less time to get to 60, then it could well be due to that added force on the back wheels so that they grip instantaneously rather than a teeny bit of slip. I suspect we're only talking very tiny fractions of a second?

Not biting today.

 

[Nictrix]

If you wanted to build on what you have already quickly, you could post your unit out to people to use and then pass on to the next person giving you the results once they had used it.
Obviously given out to people you know and trust and whos data you would like.

 

[Anonymous]

If you wanted to build on what you have already quickly, you could post your unit out to people to use and then pass on to the next person giving you the results once they had used it.
Obviously given out to people you know and trust and whos data you would like.

Is that an offer?

 

[GuidoK]

If you want to measure the performance of your vehicle and how certain mods affect it, you're better off measuring 60-120mhp acceleration or 40-70 or whatever. (some of these tests like 60-120 also take much longer so inaccuracies by the device play less of a role)
A 0-60 measurement is very much affected by the start, so the particular grip conditions that play on that exact time and can affect the outcome easily by 30%.
Unless you specifically want to test grip by low speeds (for example tyres or maybe an LSD), then the standing start is very important

 

[Nictrix]

If you wanted to build on what you have already quickly, you could post your unit out to people to use and then pass on to the next person giving you the results once they had used it.
Obviously given out to people you know and trust and whos data you would like.

Is that an offer?

I would do it but you could get all the info you needed from ours off the net as its a standard car

 

[Argyll Andy]

If you wanted to build on what you have already quickly, you could post your unit out to people to use and then pass on to the next person giving you the results once they had used it.
Obviously given out to people you know and trust and whos data you would like.

Is that an offer?

You should’ve stuck it out to me before last weekends trip

 

[sumotan]

Hi Pbondar,

OT question pls, what brand of oil are you using now ? Im presently using Shell Helix Ultra 5w-40 not sure if I need to change when I commence modding for more power.

Many thanks again

 

[Anonymous]

If you want to measure the performance of your vehicle and how certain mods affect it, you're better off measuring 60-120mhp acceleration or 40-70 or whatever. (some of these tests like 60-120 also take much longer so inaccuracies by the device play less of a role)
A 0-60 measurement is very much affected by the start, so the particular grip conditions that play on that exact time and can affect the outcome easily by 30%.
Unless you specifically want to test grip by low speeds (for example tyres or maybe an LSD), then the standing start is very important

Hello GuidoK....

Thanks for your comments...

I wholeheartedly agree with you ref 0-60

The primary reason is only to place a modded car amongst the only published data from BMW ie 0-60..

The data logger captures all the 10 mph steps and 1/8 1/4 mile etc

So a launch however bogged down / less than perfect should have settled itself down by the time it’s got to say 40..

So the 40-60 60-80 40-80 increments should be relatively stable ..imho..

The issue with say asking someone to do a rolling 40 mph then accelerate is getting the stability /accuracy of initial approach speed

I think as a simple methodology a rolling start then as you say timed sections would show more of a ‘real world’ value..

As an aside my first two runs showed despite clearly issues with traction and launch that my modded 302 bhp ish E89 accelerates on the 0-60 as fast as a stock 35i which has about the same bhp..so it’s kind of logical ?

 

[Anonymous]

Hi Pbondar,

OT question pls, what brand of oil are you using now ? Im presently using Shell Helix Ultra 5w-40 not sure if I need to change when I commence modding for more power.

Many thanks again

Synthetics are not a unified set of oils...the base material varies..the premium oils use ester bases..

I use redline they are rated amongst the best..

https://www.bimmerworld.com/Fluids/Red-Line-Oil-Fluids-Lubricants/#/filter:finder_hierarchy_2:Z$2520Series~E89$2520Z4$2520(2009-2016)~Z4$2520sDrive28i/q:

You need to be careful with regard to emissions equipment

If you still have a cat fitted then the 5-30w oil is your best choice from this manufacturer..

If you have de-catted the 10-40 is the top dog

I also use Mahle oil filters they again are rated very highly..