europeancarweb.com Z4 upgrades

[toplad]

Final part of upgrades for the Z4M Coupe

pity a few of the parts are missing, but it goes to show what can be done and confirms my thoughts on the positive effect of the strut brace, even on the Coupe

http://www.europeancarweb.com/projectcars/epcp_0904_project_bmw_z4_m/index.html

 

[flimper]

Project Z4 M Lap Time Progression
Upgrade Average
Lap Time
Part 1 Stock 100.8
Part 2 Add strut brace 98.00
Part 2 Wheel/tire upgrade 95.10
(+13 whp)
Part 3 Four-wheel brake upgrade 93.10
Part 4 Suspension upgrade 91.10
Part 5 Engine performance 90.20
(+29 whp)
Part 6 R-compound tires 89.30

Very interesting stuff....

 

[sammyz]

What was the engine performance upgrade? Couldn't see the specifics in the article, also they say they'd put an aftermarket exhaust on but I can't see that mentioned either.

Interesting, especially the performance of the strut brace on the coupe (which is supposed to be stiffer than a stiff man's stiffy) I guess it may follow that the strut brace is an even better upgrade on the wallowy old roadsters?

 

[mmm-five]

...and confirms my thoughts on the positive effect of the strut brace, even on the Coupe

That is fine if you're on track most of the time, but I bet even the most ardent track-dayer will only do 200 miles per day on a track and maybe do that once a week.

For me, I do maybe 120-170 miles every 2 months on track and 3000 miles a month on the road where the strut brace just makes the front end bounce around a lot more.

Plus it seems that the owner has spread these changes out over a year, so how do we know if it's purely the mods doing these improvements or the driver getting used to the car, or the track being as a slightly different temp, etc.

Unless these mods are done in quick succession, I cannot see how you can extrapolate anything significant from them - although I think that brakes should always be the first upgrade and normally gain you a few seconds, as do sticky tyres.

Why does part 2 quote a 13whp increase when all they've done is change wheels & tyres - maybe to a slightly smaller size which has messed up the dyno calculations?

 

[toplad]

...and confirms my thoughts on the positive effect of the strut brace, even on the Coupe

on the road where the strut brace just makes the front end bounce around a lot more.

Really I found there was less bounce, the front end was better tied down, really easy to notice on rougher/chambered roads

 

[dgm]

...and confirms my thoughts on the positive effect of the strut brace, even on the Coupe

on the road where the strut brace just makes the front end bounce around a lot more.

Really I found it there was less bounce, the front end was better tied down, really easy to notice on rougher/chambered roads

Totally agree with these comments from toplad.

 

[mmm-five]

Last time I tried it it was on one of the cars I was going to buy (standard other than the strut brace), but the front-end just would not stay put on the country B-roads where I was driving it, and it was so skittish (at the front) that I thought there was something very wrong with the car itself. But put it down to me coming from a very well handling e34 M5 (albeit 300kg heavier).

The 2nd car I tried had 18" wheels and no struct brace and that felt much more stable at the front, and even the car I finally bought with 19" CSLs felt more sure-footed than the first one.

Maybe there was something wrong with the first one after all, or maybe I've gotten more used to the Z4 after almost a year
Maybe I need to revisit it then?

 

[daz05]

What was the engine performance upgrade? Couldn't see the specifics in the article, also they say they'd put an aftermarket exhaust on but I can't see that mentioned either.

Interesting, especially the performance of the strut brace on the coupe (which is supposed to be stiffer than a stiff man's stiffy) I guess it may follow that the strut brace is an even better upgrade on the wallowy old roadsters?

http://www.europeancarweb.com/projectcars/epcp_0808_bmw_z4_m_coupe_project_car/index.html

Here are more details, seems the change in wheels accounted for some of the change and also the exhaust and filter.

 

[sammyz]

5 BHP gain from fitting a K & N filter and deleting the charcoal filter and 13 BHP gain from fitting lighter wheels.

The biggest gain in performance would be to leave the car stock and spend the mods money on driver training!

 

[toplad]

Last time I tried it it was on one of the cars I was going to buy (standard other than the strut brace), but the front-end just would not stay put on the country B-roads where I was driving it, and it was so skittish (at the front) that I thought there was something very wrong with the car itself. But put it down to me coming from a very well handling e34 M5 (albeit 300kg heavier).

?

That sounds like the alignments out to me, the front wheels probably pointed in different directions

 

[epbrown]

Plus it seems that the owner has spread these changes out over a year, so how do we know if it's purely the mods doing these improvements or the driver getting used to the car, or the track being as a slightly different temp, etc.

I can dispel such concerns - Doug N was a poster on another BMW forum, and he made those changes within a matter of a few months; it took European Car over a year to publish all the articles. He'd sold the car before they got around to it! Very annoying, as he wouldn't discuss the mods until the articles were published, and was gone by the time they were.