CDV Removed and ESS Supercharger ordered!!

I finally got around to removing the clutch delay valve (CDV) and replacing it with a modified one (http://www.zeckhausen.com/CDV.htm) . Upon first ride, I was surprised as I thought there would be a night and day difference. But now that I've been driving it for a few days, that difference is VERY obvious. I think this is the reason why....

My Z4 is my first manual transmission car so I was very adept at driving with the standard CDV. So I thought the modified one would let me drive the car completely differently (ie, sloppy) without the "jerkiness." As it turns out, the modified CDV doesn't let me actuate the clutch any differently. HOWEVER, it does change the way the car behaves when I use the clutch normally. So my actions aren't any different, but the behavior of the car is VERY different! The shifts are MUCH smoother....just what I was looking for. However, the biggest difference is one that I don't hear mentioned very often. That difference is how much faster you can get on the gas after a shift. Pulling away from a stop or shifting under hard acceleration really let's you get off the clutch sooner and on the gas WAY faster...and I'm pretty sure that equals faster acceleration!

Now on to the next mod...an ESS TS2 Superchager!!!! I'm doing dynos before and after and will post both. Thanks to the guys at Goodspeed (http://www.goodspeedperformance.com/ Scottsdale, AZ ) for taking on this project! More to come in another post.

I'll be very interested to see the results as I'm toying with doing the same thing on my 04 2.5.

Are you planning on updating any of the brake / drive line components?

azroadie said:

I finally got around to removing the clutch delay valve (CDV) and replacing it with a modified one (http://www.zeckhausen.com/CDV.htm) . Upon first ride, I was surprised as I thought there would be a night and day difference. But now that I've been driving it for a few days, that difference is VERY obvious. I think this is the reason why....

My Z4 is my first manual transmission car so I was very adept at driving with the standard CDV. So I thought the modified one would let me drive the car completely differently (ie, sloppy) without the "jerkiness." As it turns out, the modified CDV doesn't let me actuate the clutch any differently. HOWEVER, it does change the way the car behaves when I use the clutch normally. So my actions aren't any different, but the behavior of the car is VERY different! The shifts are MUCH smoother....just what I was looking for. However, the biggest difference is one that I don't hear mentioned very often. That difference is how much faster you can get on the gas after a shift. Pulling away from a stop or shifting under hard acceleration really let's you get off the clutch sooner and on the gas WAY faster...and I'm pretty sure that equals faster acceleration!

Now on to the next mod...an ESS TS2 Superchager!!!! I'm doing dynos before and after and will post both. Thanks to the guys at Goodspeed (http://www.goodspeedperformance.com/ Scottsdale, AZ ) for taking on this project! More to come in another post.

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Would love to go the ESS route BUT would it not be a better option to upgrade from a 2.5 to a 3.0 for potentially the same result AND the v.f.m. factor is retained in a future change of vehicle. As with all significant performance improvement measures it can significantly reduce the potential market wehen you look to sell or upgrade in the future.

No plan on doing any brake or drive line improvements yet. My car is my daily driver and I just want more "oomph" (oomph=fun around town!) I don't plan on driving faster...I just want better acceleration. At best, I'll do a random track day here or there and some autocross, so I don't think the brakes need upgrading for my needs...at least not yet. However, I will be adding a less restrictive air filter (BMC) to take advantage of the supercharger and increased airflow requirements.

azroadie, I'm with Alan. What's the point? with the money you're sending you can get an ///M
also about the breaks.... you'll definetly want to upgrade them.
I would for the bare minimum upgrade them to a 3.0Si setup (325 on the front and 294 on the rears).
Wouldn't cost too much... around £100 if you get one from breakers.

AlanJ said:

Would love to go the ESS route BUT would it not be a better option to upgrade from a 2.5 to a 3.0 for potentially the same result AND the v.f.m. factor is retained in a future change of vehicle. As with all significant performance improvement measures it can significantly reduce the potential market wehen you look to sell or upgrade in the future.

Click to expand...

AlanJ, depending on what you mean here, I could respond several ways. But I've wrestled with this question for nearly 2 years now and have evaluated all options in choosing to supercharge...so I certainly understand the thought process!! Here was my labored thinking.

First, there will be a huge difference between a supercharged 2.5 and a stock 3.0...even if it's a 3.0si. The supercharged 2.5 will put out around 320hp versus a 3.0si's 255hp and the torque difference is very dramatic. So if you look at trade in price, insurance, etc. I could get a 3.0si for about the same, but way less power/tq. And I've driven a 3.0si side by side to my 2.5 and while there was a difference, it wasn't enough to warrant the change. So take the difference between a 2.5 and 3.0si and double it. That's the jump I'm getting with a supercharger.

So really a more equal comparison is looking at a supercharged 2.5 versus upgrading to a z4M. If you ignore suspension, lsd, seats, etc. and focus on power, they are very similar (320hp vs. 333hp) However, the z4 will feel VERY comparable, if not faster as it will have a bit more torque but a much wider torque band. So for arguments sake, let's call them equal in performance (at least for my performance needs). Trading in my 2003 for a 2008 z4M (first year they made the color I want) would be at least 2x as much. So for about $15-$20K, I'd get a newer car (with a few thousand less miles), but to most people, it would look exactly the same. Now I could get an '06 or '07 for a few thousand cheaper, but I really love the look of my car and didn't want to change that. Also you have to consider and mods that would need redone...exhaust, DICE, remote top...I'd have to redo that in a new car AND add a much larger insurance tab onto my bill. So there's another few thousand more.

The other thing you might be asking is if I should upgrade to 3.0, then supercharge. You could do this 2 ways, swap out the engine or again, new car. Either way, if you look at the difference between a supercharged 2.5 and supercharged 3.0, the difference is negligible as the SC provides such a huge power bump to both that 20-30 extra horses from the 3.0 becomes negligible. Looking at the cost of an engine swap or rebuilding my 2.5 to a 3.0, it very cost ineffective for what you get.

Considering my next car will be an M3 sedan or M5 (gotta get a second set of doors at some point as I'll be keeping my Z4), this made sense in my situation. I get the power I want, in the car I want, with minimal hassle and effort (buying and reselling) and still get to start to put some $ away for that next car. So while expensive, the supercharger gives me everything I want while saving me about $5-10k over buying a newer model.

Lastly, I'm lucky enough to have the U.S. based ESS guys in my hometown. They have a great reputation worldwide, but more importantly, with the local BMW community here (AZBMW.org). They also work very closely with my shop, Goodspeed Performance, so that added a very nice piece-of-mind and solidified my decision.

... and the brakes? not worth going for Si brakes at least?

azroadie, your reasoning for doing the work is very similar to my own thought processes in so far that it would cost me roughly 10 - 12k to change to a M and approx half that to carry out the mods, I bought my Zed new and know its history warts and all, where as any M car would be used and at best only a couple of years newer with a few less miles on the clock and to the great unwashed it would be the same car, with that in mind if I do the work I would be planning on keeping the car for the forseeable future so resale value does not come in to it.

I would have agree with peddy about the brakes though and plan on upgrading mine to the 3.0si spec as a bare minimum.

like I said earlier looking forward to seeing the results.

Although I wimped and bought the M to replace my 3.0i I quite like the idea of what you are planning. The idea of taking what you already have and customising it is something we're all familiar with just that you are going that extra mile with it. Should be commended!!
:lol:

Thanks for the comments...I'm happy to keep discussing and will certainly post info (dyno runs, pics, etc.) as they happen.

I've been making my friends suffer the past few years by being "that guy"...you know the one who can never drive because he has a 2 seater? I can't keep this up much longer without some serious fall back ;-) So I'm putting the extra $5-10k that I would have spent on an Z4M and putting toward a 335i sedan next year or maybe a M3 sedan if I hold out 2 more years. Regardless, that's a second car not a replacement to my Z! Why...because I love MY Z4, not just any Z4, M or otherwise! 8)

As for the brakes... I got in on that group buy a while back and got the chrome calipers and painted mine black...so they look GREAT!



But I'll certainly upgrade when the time comes or if I feel I need it after the SC.

The other upgrade that I simply can't do on an M is in regards to storage space. With the battery placement, it seriously limits trunk space. Currently, I can fit 2 suitcases in the trunk (boot for all you UK people) and believe it or not, my bike!!! I race semi-pro so going to races is a must. So I'll admit this too (let the harassment begin!!!)...I had a custom made hitch that will allow me to carry 2 bikes on the back (or 2 snowboards), plus 2 suitcases and 2 people. There is simply no other convertible sports car on the market (new or old) that will let me do this! Note that you could also pull a small trailer with track wheels and tires if you wanted.



So adding the extra horses makes this one seriously fun do-it-all car!