Headers

[taz1966]

Hi
Can anybody recommend a set of headers for my Z4MR and if so where i can buy them.
I have seen various ones in the states for not a lot of money to be honest but would prefer to buy in the UK.

Sean

[beanie]

Not sure how many RHD options there are for the car. I know Supersprint sell some but there was a thread on here where someone had found one of the two versions didn’t fit correctly (istr it being the steering column so probably a LHD part)

They’re popular in the states as they got hobbled with cats in the exhaust manifold unlike euro cars that had catless csl manifolds. If yours aren’t cracked it’s probably not worth the change without doing other supporting mods imo.

If you are going to go for them, Evolve often have sales on Supersprint stuff and Black Friday is upon us so hopefully some deals to be had.

[GT Spec]

Hi
Can anybody recommend a set of headers for my Z4MR and if so where i can buy them.
I have seen various ones in the states for not a lot of money to be honest but would prefer to buy in the UK.

Sean

There are no direct fit exhaust manifolds for RHD Z4Ms as far as I’m aware. The stock Z4M manifolds are pretty good from factory (same PN as the E46 M3 CSL) so not worth the cost in changing IMO.

[taz1966]

Thanks guys.
Probably will leave it based on the info above.

[///MBan]

I have the Supersprint v1 stepped headers and they required modification to clear the steering column. They did make a good amount more power with a Severn tune though (I’m a bit hazy on the numbers now but may have been about 14% - I have thread on here somewhere).

A tune with stock headers would have still given an increase, but probably not as much.

[taz1966]

I have the Supersprint v1 stepped headers and they required modification to clear the steering column. They did make a good amount more power with a Severn tune though (I’m a bit hazy on the numbers now but may have been about 14% - I have thread on here somewhere).

A tune with stock headers would have still given an increase, but probably not as much.

Hi,
when you say modification to clear the steering column exactly what did this include and how much did it cost.
Thanks Sean

[Ed Doe]

I'd be surprised if it involved anything more than bashing one of the runners with a hammer until it cleared the column. Which sort of defeats the point in having posh headers if there are any suboptimal changes in bore and sweep.

Also sorry but I would strongly suggest taking any big power gains with a pinch of salt, the oe headers are well designed, my understanding is there's not a lot of gain to be had there with stock cams.

[robear]

Your stock headers are already the best headers for the money; however if you feel the need to spend 4k+ on exhaust, 2k on a CSL style intake and 2k on cams, you'll want the following exhaust setup -

The RHD specific Supersprint V1 header is the only header worth the upgrade and should fit the RHD Z4 M - https://www.supersprint.com/ww-en/bmw-e ... ve.aspx#!/

Those headers will require the matching Supersprint 63.5mm Z4 M specific section 1, preferably with the HJS cats. They have a slip-fit connection to the headers unlike the stock exhaust - https://www.supersprint.com/ww-en/bmw-e ... v6.aspx#!/

This setup with 272/280 cams and a CSL style carbon intake should easily yield 360 WHP or 420 BHP. There are quite a few E46 M3 making that kind of power.

[///MBan]

Okay, I stopped being lazy and found my old thread, which shows the modifications to the headers, dynos, etc. Power gains were more like 10% it seems.

I didn’t dyno stock headers with a Severn tune, so it would be conjecture to say that the Supersprint ones make more power. People are welcome to draw their own conclusions

https://z4-forum.com/forum/viewtopic.php?t=128400

[Ed Doe]

I don't mean to be 'that guy' who sits in his armchair and throws comments out about what other people/companies have done, but I'm convinced that that cut and welded mod to the supersprint manifold will have had a noticeable effect on flow behaviour and exhaust gas velocity through those two primaries. It's entirely possible that the modifications done would have had a negative effect to the point of being worse than the stock manifold (which is widely accepted to have been very well designed for the application).

I'm glad the dyno results gave you a gain, which is ultimately what we're all looking for when doing these mods, but I can't help but think you may well have got most of those gains just through optimising the tune on the stock exhaust manifold..!

(please do not take the above as me having a dig as an armchair internet engineer - based on my understanding of exhaust manifold design, I always understood that smooth radii on exhaust primaries was essential, and maintaining a constant cross-sectional area was also essential to ensure consistent volume as part of pulse tuning!)

[beanie]

If you have a look for ‘Engine masters dented headers’ you should be able to find a video where they tested the difference between a fresh and a dented exhaust manifold. It used to be on YouTube but I’m not sure it’s still there.

As I remember, it made little/no difference, much to the internets surprise!

As for the ones ///Mban had done, it looks a fair reduction in cross section so on paper, you’d think it would strangle it to some extent, but given the test I mentioned above it’s probably negligible.

[///MBan]

I honestly think the gains I ended up with are more than would be expected on the standard Euro headers with a tune but maybe could have been more without the modifications. Does someone have dyno proven gains with a Severn tune and everything else stock? Per cent gain is what we'd need to see, not hp.

Another point to consider - and on reflection this may actually be the most important - to fit the V1 stepped headers you have to use the matching S-pipe with HJS cats. Maybe any gains over the stock setup are actually due to the HJS cats?

I don't know. As I said, it's all conjecture until someone tests it

[///MBan]

If you have a look for ‘Engine masters dented headers’ you should be able to find a video where they tested the difference between a fresh and a dented exhaust manifold. It used to be on YouTube but I’m not sure it’s still there.

As I remember, it made little/no difference, much to the internets surprise!

As for the ones ///Mban had done, it looks a fair reduction in cross section so on paper, you’d think it would strangle it to some extent, but given the test I mentioned above it’s probably negligible.

I saw that as well. Made my cringe seeing them bash the headers!