Track day durability / bars

[nsk040]

I did a pretty thorough suspension refresh on my 110k mile car including Bilstein Sports but stayed with the stock springs. I got new fluid and brake lines in, and will likely go with EBC red stuff pads for a little more resiliency from the brakes - happy to shorten on-track sessions by a few laps if brakes are getting hot. 2 questions:

1) For better or worse, I didn't do coilovers with the refresh. Would the TMS (or similar) sway bar kit (front + rear) be a good upgrade that would make the car a good bit better on track? It seems like for $400 or whatever the bars cost would be a great value for my application, but wanted to see what others think.

2) Are there any known weak spots with the engine that are likely to be an issue after a few on-track sessions?

Thanks.

[zhpnsnv]

I've heard great things about the H&R sways, but in general, it will probably balance out the handling some.

Are you sticking with stock rims/tires? Maybe a better option would be a square setup.

As far as the engine goes, I'll let the track rats who've tracked their ZHPs chime in. Only thing I can think of is the oil pump nut, though I believe the ZHP has an updated part that is not susceptible to backing off and causing engine failure. If I knew were going to regularly track my ZHP, I'd probably put a baffle in the oil pan.

[derbo]

1. Sway bars reduce roll while not increasing NVH. It will make your tires work harder and too much bar will reduce independence between the two sides. IMO, sway bars are great bang for buck without lowering the vehicle. TMS bars are very nice with adjustability. I would try your stock endlinks and if necessary order endlinks after testing.

2. Oil Pump nut is a common issue on the M54 but as most mention ZHP has an updated nut (which is basically a nut with locktite) that helps with this issue but does not 100% prevent it. The other issue is the stock harmonic balancer can slip which ends up causing the 1st problem. The only real solution is to replace the balancer with the ATI one but it is around $1000.

With that said,

I have no issues at the moment with the M54, but that doesn't mean I wont in the future. Like Marc said, if serious HPDE/Track use is under consideration, Oil pan baffle, + harmonic balancer should be taken into consideration. Outside of that, have fun! :)

[slater]

1. Sway bars reduce roll while not increasing NVH. It will make your tires work harder and too much bar will reduce independence between the two sides.

very good point, derek... not many people understand this. there is definitely a fine balance - well, it's math actually ;) - between spring rate, swaybar size, and suspension travel (and CG). i'm not smart enough to understand it all, but i am aware of what feels right and what feels wrong. :)

[derbo]

very good point, derek... not many people understand this. there is definitely a fine balance - well, it's math actually ;) - between spring rate, swaybar size, and suspension travel (and CG). i'm not smart enough to understand it all, but i am aware of what feels right and what feels wrong. :)

Yup!

The TMS street bars are 27/21mm and the SPECe46 ones are 30/21. :)

I currently have a 30mm Hotckis up front with a stock M3 rear 21.5mm

[slater]

Yup!

The TMS street bars are 27/21mm and the SPECe46 ones are 30/21. :)

I currently have a 30mm Hotckis up front with a stock M3 rear 21.5mm

wow, 30mm!

i was running 26/20.5 (stock M3 front/non-M 'vert rear) on the ZHP, going to try 26/23.5 on the Touring first (picked up a 23.5mm UUC rear bar), then i'll probably go back to the 20.5 after i end up pointing the wrong direction. ;)

[derbo]

wow, 30mm!

i was running 26/20.5 (stock M3 front/non-M 'vert rear) on the ZHP, going to try 26/23.5 on the Touring first (picked up a 23.5mm UUC rear bar), then i'll probably go back to the 20.5 after i end up pointing the wrong direction. ;)

My 30mm is set to medium and it feels like the 27 on full stiff. [emoji51]


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[ZHPizza]

Yup!

The TMS street bars are 27/21mm and the SPECe46 ones are 30/21. :)

I currently have a 30mm Hotckis up front with a stock M3 rear 21.5mm

Wait I thought M3 rear bars didn't fit on non-m cars???

Edit: Now I see that you have a full M3 rear subframe. Makes sense.

And here's a 30mm Turner scratch & dent for cheap if anyone wants to snag it:

https://www.ecstuning.com/b-turner-motorsport-parts/e46-m3-turner-front-sway-bar-30mm-scratch-and-dent/e46m3-f30-swaysd/

[derbo]

Wait I thought M3 rear bars didn't fit on non-m cars???

Edit: Now I see that you have a full M3 rear subframe. Makes sense.

And here's a 30mm Turner scratch & dent for cheap if anyone wants to snag it:

https://www.ecstuning.com/b-turner-motorsport-parts/e46-m3-turner-front-sway-bar-30mm-scratch-and-dent/e46m3-f30-swaysd/



Yup, I have an M3 rear end. :)

[Stigissimo]

wow, 30mm!

i was running 26/20.5 (stock M3 front/non-M 'vert rear) on the ZHP, going to try 26/23.5 on the Touring first (picked up a 23.5mm UUC rear bar), then i'll probably go back to the 20.5 after i end up pointing the wrong direction. ;)

I've got the UUC front and rear bars on my wagon.

Roll is obviously reduced from what I remember my stock ZHP to be, and change of direction is fantastic.

This could be dummy math, but I suspect the 23.5 on the back of the wagon has a significant benefit in preventing some of the extra roll you get in the back of the touring due to weight and higher CG.

[Sockethead]

I have UUC front and rear too. Doesn't affect daily driving. I have stock front end links and, I believe, they are set on the middle hole on the bar (there are three holes for adjustment). I have adjustable end links on the back bar set to the stock end link length.