Brunton Stalker M-Spec BMW N52

Sticker tires!

Wow, just wow.  Sounds gnarly and just love the dash layout.

Is the safety glass a stalker part, or something you are having custom made? Will it curve like the current windshield?

bgkast (Forum Supporter) said:

Is the safety glass a stalker part, or something you are having custom made? Will it curve like the current windshield?

It's just a flat panel I'm having cut.  Most states are fine with the lexan that Stalker uses (in the pictures here).  5/16 lexan will out perform safety glass any day so I will be fine with that as well once I have a license plate. 

Alex

No real news but thought I'd update on the Michigan titling process.  So far, so good. Got the police inspection done maybe 6 weeks ago (awesome officer who started off on the phone with a bunch of car-guy questions about what it was and said this was his favorite thing to get called for).  We spent more time talking about the Corvette in my driveway than checking anything on the Stalker :lol: He's buying a ZL1-1LE so lots of questions on that too.

Went to a very, very confused secretary of state clerk who muddled through the process with enthusiasm but I wasn't super confident we got it all in correctly.  However, got the letter yesterday (5-ish weeks later) that they're sending the VIN installer out soon and to wait for a call.  So, still looking good for a memorial day first legal drive!

Alex

First legal road drive!  Headed to my wife's studio, about 6 miles away.  Drives really well for a super immature calibration.  Over 4k RPM the sound lights up and it's spine tingling!

Once I got the police inspection scheduled the rest of the licensing process was an easy game of hurry up and wait.  Four contact points needed with the state, not terrible, I guess.  Only took a month total.

No major issues, only odd part was that it struggled to idle on startup after the soak, felt more air than fuel, thinking my IAT sensor might not be getting at the true air temp that's going in the intake.

Tinted the tail lights.  Still not sure this is the final answer but it's better:

Haven't posted many pics of the finished engine compartment, pretty happy with the overall look:

Next is to finish up enough speed density tuning to pick the throttle transition line to setup the ITB blended tables, then to the dyno!

Alex

That engine setup looks perfect. Excellent work. 

No weight yet but finally a couple videos!  It's tuned well enough to drive it without constant attention to the cal so getting more fun by the minute.  

The camera sound sucks, need to figure out a solution for that since the sound is awesome! There's none of the resonance you hear in the mic, just clean ITB goodness.  Same for the normal driveoff vid, no resonance off camera but it sounds like it's lighting the whole car up in the video.

Still clutching a bit most of the time, some more SW to write to send the megasquirt the shift cut command.

Nice braap through a MI left:

See next post for vid 2, didn't realize there was a limit...

Alex

Normal driveoff.  This has been way more work to cal than the heavy throttle side.  Lot's of conditional filtering on the electronic throttle to manage the lash in the sequential.  Getting REALLY good 90% of the time now with just the occasional clank I need to keep working on.  Once it's engaged and over about 2500 RPM the filtering all goes away for the super direct ITB response.

Next up is some yarn tufts on the hood to get a vent properly placed, then dyno time to finish >6500 RPM and do the spark table, just a conservative guess right now.

BTW, cupholders are like the best part of the car.  Anyone who made fun of them is just plain wrong.  Open car, always sunny, water is key!  Need to do some insulation on the bottom because it's hot water in 10 min :lol:

Alex

Love this - the sequential shift and the ITB's are the business.

I can only imagine how epic it is to drive this car. 

Congrats on getting featured in a magazine, even if it wasn't GRM. Car and Driver. I saw it, and I'm like "I recognize that car."

I found this again and read to the end.....(so far), but this shot is money!!! C8 DD and copious amounts of ROAD GRIME...OHY well done ALEX!!!! (left you a pm diff related)

esuvee said:

9/22/19:

Been super busy with work this summer but also plugging away for a few hours each weekend on the Stalker.  

Brake and clutch plumbing are 100% done, a bunch more aluminum panels are done, hood latch cables are done, some other stuff I'm sure.

I am going for a 1960's look on the engine with the ITB's.  To give the look of fuel lines to each "carb" I'm doing the idle air circuit out of hard line.  So far I'm thrilled with how it's turning out.  Should look awesome when the ITB's are painted carb color and the velocity stacks are polished.  Just need to spend a ton of time on the valve cover eventually to make it look less plastic.

This engine from Goodwood is my rough inspiration.  Obviously a *lot* of differences but sort of a conceptual guide.

Also finished the cup holders (I know! gasp.).  I try to avoid visible welds since I'm not that great at it but I couldn't figure a way around these so I just held my breath. They turned out good enough to be visible under some textured black paint that I plan to use on the aluminum interior panels.

Getting close to being ready to blow it apart and start over like a regular kit car!  Still mounting a few fuel system components and I need to swallow the big bill for oil plumbing.  Trying to decide where in the process electrical fits.  I think I'll hard mount everything now but wire it on final assembly?  

Alex

Hey Alex- I'm getting to the point of needing to grab vacuum signal from my ITB's. They don't have provision for vacuum take offs, but do have injector ports. I was planning on using the ports in the head and coming up with an adaptor for the ports in the throttle bodies. They are standard 14mm, and it looks like you did the same. I'd like to somewhat copy what you did- do you mind telling how you managed that?  Thank you so much!

Teh E36 M3 said:

Getting close to being ready to blow it apart and start over like a regular kit car!  Still mounting a few fuel system components and I need to swallow the big bill for oil plumbing.  Trying to decide where in the process electrical fits.  I think I'll hard mount everything now but wire it on final assembly?  

Alex

Hey Alex- I'm getting to the point of needing to grab vacuum signal from my ITB's. They don't have provision for vacuum take offs, but do have injector ports. I was planning on using the ports in the head and coming up with an adaptor for the ports in the throttle bodies. They are standard 14mm, and it looks like you did the same. I'd like to somewhat copy what you did- do you mind telling how you managed that?  Thank you so much!

I did go to the injector ports on the throttle bodies since I was using the injectors in the head for fuel.  I *think* I drilled them out first and then tapped to 3/8 pipe but they may have been just exactly the right size for the 3/8 pipe tap.  I know I had to cut the pipe to AN adapters short so they didn't hang out in the airflow.  They then go to a box with and idle air valve on it.

Worked really well, having big airflow to each cylinder (3/8" hard line for me) means I can idle with the throttles 100% closed.  Makes everything way easier to synch up and less fidgety.  This car has a rock solid idle, better than any single throttle car I've ever done.  The MAP signal is also decent due to the accumulator nature of the box.  You can see the pulses but some mild filter settings on the Megasquirt make it more than workable.    The box is about 2x3x4" and I pull the signal off one side of it with no restrictors.

Alex

Thank you! I figured something out that hopefully works. I hope you're enjoying the car. 

This project is simply fantastic!  Did you ever sell the Volvo?

Amazing build quality! Coincidentally I'm hoping to add Megasquirt and BMW M54 ITB's to an I6 build. The BMW ITBs come with a cylindrical vacuum plenum that mounts next to the fuel rail. I'm planning to tap into this pipe for MAP and idle control like you did with your custom plenum. I'm only using Microsquirt though. Do you think I'll have a problem tuning the ITBs with only 2 injector batches and wasted spark?

maschinenbau said:

Amazing build quality! Coincidentally I'm hoping to add Megasquirt and BMW M54 ITB's to an I6 build. The BMW ITBs come with a cylindrical vacuum plenum that mounts next to the fuel rail. I'm planning to tap into this pipe for MAP and idle control like you did with your custom plenum. I'm only using Microsquirt though. Do you think I'll have a problem tuning the ITBs with only 2 injector batches and wasted spark?

No, you'll be fine!  I got it running at first with batch injection and wasted spark for simplicity and it really ran great right off the bat.   Also good plan on the stock air plenum.  The only reason not to use it is appearance and hood height.  I wanted a little more custom look and needed to cut the engine height down by every means possible, that was the highest pole at one point.   Very roughly looking at both of them I think it's a similar volume to my idle air box.

There is some chance I am getting some MAP signal cleaning via the long, varied length tubing before the box but who knows?

Alex

In reply to Loweguy5 (how many cars will I buy this month before my wife leaves?) :

Yes, to a guy who works in my building at GM.  Was hoping to see the car occasionally but then Covid...

Alex