The Dunklenator (Poor Man's Z8 Project)

[ProductUser]

Very cool!

[IndianaRoadster]

Congrats, always a great feeling when you can experience the fruits of your labor.

[Boomster]

Awesome project! I wish I had even half your mechanical abilities!

[Mr Bingley]

Pretty fancy--it's been a long haul, but you have actually arrived--congrats!

[BladeRunner919]

Brilliant - what a great job!

[ProductUser]

Curious...How are you going to pass emissions with that beast?

[TexaZ3]

Keeping it green, I assume?

[CoconutPete]

Curious...How are you going to pass emissions with that beast?

There's a very real chance that AZ does not do emissions on it anymore. Here in NC they stopped doing it on my 2000 maybe 2 years ago.

[ProductUser]

There's a very real chance that AZ does not do emissions on it anymore. Here in NC they stopped doing it on my 2000 maybe 2 years ago.

From AZ DOT
Vehicles that are model year 1967 and newer and more than 5 years old require emissions—this includes gasoline and diesel-fueled vehicles. Alternative fuel, flexible fuel (E85) and hybrid vehicles also require emissions. Newer vehicles are exempt for the first 5 years of registration.

Note: I don't know if historic cars require emission testing.

I'm sure BB can tell us; this is his area of expertise Where are you BB?

[IndianaRoadster]

Here in Indiana, at 25 years you can get a classic license plate which does not require emission testing. We have to test every 2 years. I tested this year, so one more time and I'm done!

[BimmerBreaker]

The Arizona emissions process does not require the original engine to be installed nor do they even check the engine bay. For this model year you are allowed up to 2 readiness monitors not be set and still pass (which is how it is now). I do have a few pending CEL's for some things that I need to figure out, because they should have been disabled in the tune but they are still popping up CEL's (such as the DMTL and post-cat O2's). Emissions is next on my list to sort through so I will likely be focusing on that next...

Keeping it green, I assume?

That's the current plan... the green has grown on me. Perhaps more prescient is the fact that my original plan for purple wouldn't look good with a tan interior and I don't really want to have to source a complete black interior and then not be able to drive the car while installing it. Between the fabric stuff and the new job I definitely do have a little less time these days, my work schedule has been getting a bit busier so I want to be able to enjoy the car now instead of spending all my free time working on it


The new expansion tank came in today... got home from work and installed it. Here it is installed while pressure testing (did a "cold bleed" right afterwards)



Drove it somewhere else today to piss off different neighbors Eventually I will photograph more angles of it but the rear is a work in progress currently and I don't want to show it until at least the fiberglass is done...



Ripped it around for a test drive (in Mexico, of course). Here's a little glimpse of how it's moving these days...



I got to say, it's a blast with the 3.15, I can actually enjoy the engine instead of just shifting all the time! I love the feel of the rear end as well, completely planted but the car still has nice OE like compliance on rough roads

[Caker]

Well done sir, very cool project

[dbarton62]

The Arizona emissions process does not require the original engine to be installed nor do they even check the engine bay. For this model year you are allowed up to 2 readiness monitors not be set and still pass (which is how it is now). I do have a few pending CEL's for some things that I need to figure out, because they should have been disabled in the tune but they are still popping up CEL's (such as the DMTL and post-cat O2's). Emissions is next on my list to sort through so I will likely be focusing on that next...

On my phone's stopwatch I timed 0-60 a few times and all were under 5 seconds. I do believe you had wheelspin off the line. Very respectable. Well done.



That's the current plan... the green has grown on me. Perhaps more prescient is the fact that my original plan for purple wouldn't look good with a tan interior and I don't really want to have to source a complete black interior and then not be able to drive the car while installing it. Between the fabric stuff and the new job I definitely do have a little less time these days, my work schedule has been getting a bit busier so I want to be able to enjoy the car now instead of spending all my free time working on it


The new expansion tank came in today... got home from work and installed it. Here it is installed while pressure testing (did a "cold bleed" right afterwards)



Drove it somewhere else today to piss off different neighbors Eventually I will photograph more angles of it but the rear is a work in progress currently and I don't want to show it until at least the fiberglass is done...



Ripped it around for a test drive (in Mexico, of course). Here's a little glimpse of how it's moving these days...



I got to say, it's a blast with the 3.15, I can actually enjoy the engine instead of just shifting all the time! I love the feel of the rear end as well, completely planted but the car still has nice OE like compliance on rough roads

Timed the run a few times on my phone's stopwatch. All were under 5 seconds. Did I detect wheelspin off the line? Very respectable. Well done.

[cyberman]

Starting September 2019 until now, you've taken us all on a wonderful ride. Thanks for spending the endless hours documenting the work. I can't wait to see the cosmetics done and everything straightened out. You'll have one kickin sleeper to surprise those guys in their built-up pickup trucks.

[BimmerBreaker]

Well done sir, very cool project

Thank you!

Timed the run a few times on my phone's stopwatch. All were under 5 seconds. Did I detect wheelspin off the line? Very respectable. Well done.

No wheelspin, I was just rolling gently into the throttle to about 10mph. I was also shifting a few hundred rpm. Wasn't 100% full throttle either - still no pedal stop installed. Once I get that installed I'll do some real sprints to 60 to try to establish a 0-60 time just as a reference point for those interested

I will say, it definitely feels faster than my S54's, at least from a dig and when stepping on it from the mid rpm's. S54 and it's RPM's might take it on the highway but I'm not really sure... I know horsepower is a factor of time and torque, but I don't know if that means that 330hp at 8000rpm is faster than 330hp at 6000rpm. That's something I should probably study a bit to get a better understanding of it.

My gut tells me that since horsepower is really just torque * time that 330hp is 330hp regardless of where in the rpm band it falls and the fact that the N62 gets there sooner may be advantageous rather than negative? It seems the main advantage of the S54 is that between shifts it will land at a point in the RPM band that provides a little more horsepower

I plotted the dyno graphs on one spreadsheet so I could compare them (not sure if I've shared this before), below is the S54, N62 4.4 plus the M54 3.0 and M52. The last two are just as a point of reference since Z3's came with those...
The y axis is torque in N-m. These figures were all pulled straight from BMW technical releases - I sampled data points every 1000rpm



The area under the curve is clearly much broader on the N62, so it makes sense it feels faster low down and in the midrange. The N62 still feels very healthy up top though, but it isn't a screamer like the S54...

- - - Updated - - -

Starting September 2019 until now, you've taken us all on a wonderful ride. Thanks for spending the endless hours documenting the work. I can't wait to see the cosmetics done and everything straightened out. You'll have one kickin sleeper to surprise those guys in their built-up pickup trucks.

Thanks! Haha. Was quite a ride for myself as well! Frankly I'm still surprised it's finished to this stage, but each time I drive it it feels more and more real... cosmetics are next on the agenda!

[zellamay]

"I will say, it definitely feels faster than my S54's, at least from a dig and when stepping on it from the mid rpm's. S54 and it's RPM's might take it on the highway but I'm not really sure... I know horsepower is a factor of time and torque, but I don't know if that means that 330hp at 8000rpm is faster than 330hp at 6000rpm. That's something I should probably study a bit to get a better understanding of it.

My gut tells me that since horsepower is really just torque * time that 330hp is 330hp regardless of where in the rpm band it falls and the fact that the N62 gets there sooner may be advantageous rather than negative? It seems the main advantage of the S54 is that between shifts it will land at a point in the RPM band that provides a little more horsepower "
llllll
As we all know, engines have different purposes. If you race, an S54 might be better, but for the street, where one needs power suddenly and quickly, the N62 will obviously be better. 330 hp at 8000 is exciting, but 330 hp at 6000 rpm is far more valuable on the street. This is one reason I never did the M50 swap on my S52: not willing to trade mid-range power for top-end power. I like the car to go "now" when I use the gas pedal. ..... I'll bet that N62 is so responsive that it starts accelerating BEFORE you use the gas pedal.

[z3forlife]

Yes. This has been fun to follow. I just had something unexpected happen yesterday. I had the throttle cable come out of the pivot arm after a quick romp. I had to limp home at idle speed in 5th. Pulled the under tray and found the cable out amd the rubber grommet missing. One of those small things to check out. WE NEED LONGER VIDS please.

[BimmerBreaker]

As we all know, engines have different purposes. If you race, an S54 might be better, but for the street, where one needs power suddenly and quickly, the N62 will obviously be better. 330 hp at 8000 is exciting, but 330 hp at 6000 rpm is far more valuable on the street. This is one reason I never did the M50 swap on my S52: not willing to trade mid-range power for top-end power. I like the car to go "now" when I use the gas pedal. ..... I'll bet that N62 is so responsive that it starts accelerating BEFORE you use the gas pedal.

That's a good point. At the end of the day I built it to have a wonderful V8 exhaust note in a droptop Z car which I definitely accomplished. And I built it to be drivable around town, which the V8 is well suited for with that torque. If I'm hung up on it being an "S54 killer" I could always pluck the 4.4 out in favor of a 4.8...

And yeah, the N62 pulls as soon as you start pushing the pedal. The response is very good, I thought I would want a more responsive throttle map (my S54's are tuned with a pretty crazy throttle response) but I am very happy with it as it is now

Yes. This has been fun to follow. I just had something unexpected happen yesterday. I had the throttle cable come out of the pivot arm after a quick romp. I had to limp home at idle speed in 5th. Pulled the under tray and found the cable out amd the rubber grommet missing. One of those small things to check out. WE NEED LONGER VIDS please.

Mine did something similar on the first test drive. The DBW Z3's use the same pedal as the cable throttle Z3's, a little metal linkage arm connects the pedal to the potentiometer and that arm popped off on my first test drive lol...

I will work on some longer videos soon. I'm never sure if people are actually interested in the videos or not but a few people asked me for longer vids so I'll work on that next time I take it out

[IndianaRoadster]

Keep making them! I love to watch, in fact it got me thinking that it would be fun to make one of my own. I'll have to get my son to go with and hold the camera. We have some cool interstate on ramps and egress with Twisties.

[BimmerBreaker]

I need to find a better camera angle... oops. Also think I need to figure the clutch position switch out, it doesn't work currently, so the engine continues to rev a bit extra sometimes when shifting. But I wanted to take it out for a spin today, at least you can hear that exhaust note... mmm...



Launched it a couple times as well, was hoping to be able to record some 0-60 sprints but of course you can't see the gauge cluster lol. Hit 95 at one point at 3:40 in the video (this was, of course, filmed on private roads in Mexico)

Open to suggestions on a good phone mount... Lol

[spfd72]

Are you still driving without power steering? That N62 has a rather unique sound-not at all like a traditional American V8.

[Hoyt Clagwell]

I love that exhaust note! It seems that you could drive the car around lightly on the accelerator and sound quiet enough not to bother the neighbors and then when your in an appropriate location, open her up to hear that authoritative but not abrasive roar. That's what I'm getting anyway. A perfect, street-able roadster. It looks like it pulls like a freight train as well.

[Boomster]

I wish my Z8 sounded that good!

[BimmerBreaker]

Are you still driving without power steering? That N62 has a rather unique sound-not at all like a traditional American V8.

Yeah still no power steering. It doesn't bother me at all once I get moving and it helps me get a feel for how much stress I'm putting through the steering system. It's probably ready for power steering now that I have more confidence in the car and the steering but it just hasn't been my main priority. Maybe this weekend I will tinker on that a little bit...
And yeah I love the sound. It has a pretty distinct "wail" to it that I really like, sounds a lot more exotic than an American V8, but without being overly high pitched

I love that exhaust note! It seems that you could drive the car around lightly on the accelerator and sound quiet enough not to bother the neighbors and then when your in an appropriate location, open her up to hear that authoritative but not abrasive roar. That's what I'm getting anyway. A perfect, street-able roadster. It looks like it pulls like a freight train as well.

It's still pretty loud at part throttle it just might not come across as much in the video lol. It definitely pulls very strong! It's addicting having it push you back in the seat when digging into the throttle...

I wish my Z8 sounded that good!

Open up the exhaust a little bit... I'm sure it'll sound even better than mine


I took it out again earlier today to monitor the coolant temps as when looking at it after some previous drives I noticed both radiator hoses seemed very pressurized and hot to the touch (the cold side just a little bit cooler) after parking it. So I drove it around today with my INPA laptop so I could make sure first of all that the temperature gauge on the cluster was reading the correct value of the engine coolant outlet temp. I also wanted to monitor the engine inlet vs radiator outlet temperatures to ensure it was cooling adequately



With the coolant temp pulled up on the "secret" menu (shown above with the car off after sitting for a few minutes), I was able to confirm that the coolant temp gauge is showing the engine outlet temp which is correct. I drove it about 10 minutes after it hit operating temperature. Most of the time it was completely fine... the inlet would go up to ~97 after driving hard then down to ~93 or so when idling or driving slow. The engine outlet temp was mostly around 100 but never exceeded 105 which is the proper operating range for an N62 as they have 105C thermostats and will vary their operating temperature from about 99-105C in my other cars

The secret menu test also shows RPM and I was able to verify that the RPM is reading correctly. That wasn't a major concern for me but it was good to double check that and confirm it is displaying the right values

However, later in the drive I was driving it a bit harder and the outlet temp started to creep up to the upper 90's and after a full throttle blast to ~80mph I looked down it showed 107 outlet for just a brief second When that happened the outlet was at 101, it quickly rose to 105 as the inlet dropped to ~103 as I was coasting and slowing down, then the inlet dropped to the upper 90s but the outlet stayed at 105 for a bit longer than it had previously in the drive so I drove it home slowly and idled it a few minutes to let it circulate coolant and cool things down. It dropped to 100 and I shut it off. It never exceeded 105, but was still enough to worry me. The engine inlet (cooled coolant from the radiator) should obviously never exceed the engine outlet temperature

It is over 100F here when I test drove it, which surely doesn't help things. But perhaps most importantly, I don't have any lower ducting in place below the radiator, so I think what may have happened is when driving it hard, all the air simply rushed underneath the radiator, instead of through it. The lack of sufficient airflow plus the extra heat from driving the engine hard was not a good combination. So the first step will be to install the lower ducting piece from an S52 Z3M (as the S54 parts have a duct for the oil cooler which I don't have). If the ducting alone isn't enough I would probably try swapping to a non-M bumper first to see if that helps, if it does maybe I will just run a non-M bumper over the summer

[R Shaffner]

I don't know about the N62 crowd, but many of us M62 owners have ditched the 105C MAP thermostat for the cooler 88C one that fits our cars. It's nice having the engine cooler overall, and especially nice to have it cooler BEFORE one jumps on the throttle.

Maybe the one listed here?
https://www.bimmerforums.com/forum/s...n62+thermostat