The Buchka 242 Fake Racecar

This is such an insane build I'm pretty certain it will end up on buildthreads some day.

Given all the custom work and endless hours, do you reckon it will be driven as hard as it should once finished?

amerbritcan said:

So you guys are short

I can't get seats low enough for my taste. I drove Acurry6's orange 242 with the seats bolted right to the floor and had a moment of "ooh, this I like" before I even started the thing.

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About 5'9", so slightly below average? Keep in mind that the floor of our car is 0.75" up from the bottom of the rocker panel seam. It's more than 3" lower than the top of the seat mounting hump on a 240, so saying it's going to be a raised seating position is all relative.

Arn02 said:

This is such an insane build I'm pretty certain it will end up on buildthreads some day.

Given all the custom work and endless hours, do you reckon it will be driven as hard as it should once finished?

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Thanks! We'll definitely be flogging it on track days. The odds of doing anything wheel-to-wheel is small.

Ended up taking a pleasure cruise down to Winding Road Racing in Fountain Valley today to look at racing seats. They had a great deal going on some Oreca seats, so we splurged.

Oreca is a French constructor that decided to start selling seats, belts, suits, gloves and so forth to club racers. They mainly buy items from other manufacturers, re-brand, and sell at a lower price point.

These are the "Turn One by Oreca" CUP. Oreca is changing their gear brand to "Oreca Gear" so these Turn One seats are being phased out.


They are re-branded OMP seats, which means they carry the same FIA certification as the OMP counterpart.

Here's the approximate position we'll be mounting it in:


It leaves ~70mm to the main hoop x-brace and should be high up enough to where the front edge of the hood is visible. We're planning on putting the driver seat on sliders and just leaving the passenger seat fixed. Both seats and two sets of mounting brackets cost us $920 out the door.

With the seat roughly positioned we could also play with the shifter position. The stock location is just slightly too far back and too low. I think we'll be able to get away with shortening the throw and making an extended and offset lever.

Karl Buchka said:

The seat is going to end up being raised quite a ways off the floor because of that whole needing-to-see-where-you're-going thing.

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No, you gotta keep that CG low broham! Bolt seat to floor and rig up small cameras and video screens to replay what's going on around you.

I've always been able to see the hood pin on the drivers side of my car, but I think I'd go a bit lower in a track car. For street/autoX, I felt better sitting a bit higher. Our lemons car has the seat riser cut out and some square tube welded directly to the floor pan and the side mount brackets are bolted to those. Suits the tall/big driver.....and Rob could still see out the windshield...

http://www.pbase.com/towerymt/image/144135140.jpg

Poor rob...

Rear box is lookin' strong, quite strong. I'm happy to help again whenever you guys are turnin' and burnin' on this (assuming you're back to work this week).

Were you able to "fit try" seats at Winding Road? I need to see if I fit in the Sparco Sprint seat.

Sweet deal on the Oreca re-branded OMPs!

towerymt said:

I've always been able to see the hood pin on the drivers side of my car, but I think I'd go a bit lower in a track car. For street/autoX, I felt better sitting a bit higher. Our lemons car has the seat riser cut out and some square tube welded directly to the floor pan and the side mount brackets are bolted to those. Suits the tall/big driver.....and Rob could still see out the windshield...

http://www.pbase.com/towerymt/image/144135140.jpg

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Thanks for the info. I think we'll install the seat at a taller position on the seat bracket. That way we can always lower it later.

Duder said:

Rear box is lookin' strong, quite strong. I'm happy to help again whenever you guys are turnin' and burnin' on this (assuming you're back to work this week).

Were you able to "fit try" seats at Winding Road? I need to see if I fit in the Sparco Sprint seat.

Sweet deal on the Oreca re-branded OMPs!

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Thanks dude(r). We are back at work this week. Not sure when we'll be back out for more wrenching. We'll probably drop in to mock up the pedalbox once it comes in. I'll keep you posted.

They had a decent selection of seats at Winding Road with the ability to plant your ass in any one of them. I'm pretty sure the Turn One RAC/Oreca Start FG seat is a re-branded Sprint, and that sells for about $100 less than a Sparco.

I was just joking around, wasn't taking any actual crack at anyone's height.

I know I'm a mutant giant, but not as mutant giant as others.

This Project is so awesome, always looking forward to the NeXT updates!!

Kj?r p?!

Waiting on material to make seat mounts and the pedal box bracket. In the mean time we took one of the dampers apart to see how much was inside.







Conclusion: All of it.

Since these are originally motocross/ATV dampers, they will need to be re-valved to match the characteristics of the car. The non-reservoir end will also need to be extended to reach between the body and control arm. Currently pricing rebuild parts and looking at replacement shims.

Made some bespoke tooling to further disassemble the dampers. The damper cylinder and cylinder head are threaded together with loctite and are a complete bear to separate, so a means of clamping the **** out of it in the vise was required.

The solid piece was turned to a tight slip fit inside the damper cylinder and the hollow piece fits on the outside. It has flats to anchor it between the vise jaws and a slit to allow for compression. Copper shim stock was used to avoid leaving wrench marks on the aluminum cylinder head section.


Clamp in the vise like so proceed to reef on it with the biggest crescent wrench around.


Removing the cylinder head reveals the compound inner cylinder that provides hydraulic bump stoppage on these MX dampers.




Remove it, throw it in the garbage, and replace the damper shaft with a longer equivalent and suddenly you have ~30mm of extra damper travel with no changes to external dimensions.

Also got a new Steuerger?t in the mail, straight out of Lithuanian eBay.



Been spending a lot of time looking at the electronics architecture for the car lately and I think it's been locked down.

We were originally planning on using an MS3 for engine control, but that had always involved making quite a few compromises on the design. After doing some trades, the options were narrowed down to either a Life Racing F88, a Pectel SQ6M, or a Link G4+T. They're all available at roughly equivalent prices, so it really became a question of support, usability, and built-in features. The Link ended up coming out on top for several reasons. I'll be looking to buy one fairly soon along with an HP Elektronik Powerbox.

Throwing stones from a < 1mm thick glass house here, but the Link tuning software is pretty bad. Have you tried it?

Link's just another company like most of the Ozzy ECU companies, and only the G4+ doesn't suck completely IMO (G4+ introduced decent models like VE and injector parameters, etc not present in G4 down). The other two options you mentioned are supposed to be pretty highly respected hard core motorsport devices. Not really in the same category as Link IMO. 2c delivered.

Curious as to what compromises MS3 would have made you make. Care to share the details? As much as I hate it like no one else, it's pretty fully featured and capable. What do you need the ECU to do exactly?

FreeEMSFred said:

Throwing stones from a < 1mm thick glass house here, but the Link tuning software is pretty bad. Have you tried it?

Link's just another company like most of the Ozzy ECU companies, and only the G4+ doesn't suck completely IMO (G4+ introduced decent models like VE and injector parameters, etc not present in G4 down). The other two options you mentioned are supposed to be pretty highly respected hard core motorsport devices. Not really in the same category as Link IMO. 2c delivered.

Curious as to what compromises MS3 would have made you make. Care to share the details? As much as I hate it like no one else, it's pretty fully featured and capable. What do you need the ECU to do exactly?

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I have used the Link software and I thought it worked just fine.

I have a couple of friends who are dealers for Pectel and Life and they both strongly dissuaded me from Pectel and partially from the Life. Between the two of them there isn't an ECU on the market that they haven't installed and calibrated. They both feel the Link G4+T is one of the best (if not the best) bang-for-buck ECUs out there right now.

Cosworth isn't interested in offering any support to independent end-users, they charge you to add non-standard trigger patterns, the SQ6M has latent hardware faults that can cause the ECU to die, you need to request a new license every year to connect to your ECU, they charge you extra to add new CAN devices, and a number of the features they tout in the brochure are either untested or plain don't work.

The Life was certainly attractive, but I would have had to pay extra to get DBW support and the unit I had available to me was from the UK, which means I would have been unable to get support from any Life dealers in the United States. Setting it up with DBW and four-channel VVT would also have eaten up almost all the spare IO. The high-speed and burst logging it offers is very attractive though.

The Link has more IO than the Life or the Pectel, does dual DBW out of the box, allows for custom trigger patterns and CAN devices to be defined by the end-user, is cheaper than either of the other options (even at the heavily discounted rate I was able to get the Life or the Pectel), and has dual on-board lambda.

Megasquirt won't do DBW (probably ever) and the only way to get four-channel VVT is to use an MS3+MS3X which I absolutely ****ing refuse to ever spend a dime on. It also doesn't have nearly as much IO as the Link. Getting a custom VVT trigger pattern in the MS is also contingent on convincing the developers to write you one, which I would prefer not to bank on.

Excellent reply.

Links have deadlock issues, too, BTW. I know a guy who was using one in his twin turbo 6 cylinder high performance plane, and it nearly killed his pilot and damaged quite a lot of carbon fibre in the belly when it came down dead stick.

I can give you DBW for free, but I've not had my hands on a true VVT engine to play around with that, yet. It's an easy problem to solve, though. Trivial, really. And our tuning software is the absolute worst of the bunch, possibly bar none. Working on that...

Amen on the MS3X sentiments Hackity hack. And the licensing/feature tricks ah la motec, too. Yuck.

I don't see on-board lambda as a plus, rather the opposite. It's popular to add that as a feature, but you're then stuck using a particular implementation of something that's quite easy to get wrong, really important, and may not be the best choice.

Aside from all of that, I didn't quite get clear what you needed:

• Quad VVT, got it.
• DBW you need, but two, or one? Excuse me for not reading the rest of the thread!
• Custom trigger patterns? Why? What? Details? Curious!

I love writing decoders, they're the most fun bits of code to write IMO. Wise to not bank on too much of J&K's time these days, though.

Trick question: Which one of your friends has run mine? Only teasing but the statement was a bit bold, to say the least.

And then I went to look at the link website and I got this:

The owner of www.linkecu.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website.

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Because they don't use SSL and play strange redirect games. Ahh well, can't win em all.

The thunder box certainly is pretty extensively equipt. Should do nicely. Pretty much everyone here in NZ runs Link stuff on their cars and most are fairly happy. Nothing's without a few warts, though.

It's always some kind of compromise. At this point I feel like the Link ticks the most boxes for a very attractive price. I'm not necessarily looking for another project with the ECU. I'm happy to go with a more commoditized product that is more likely to "just work."

There's no hard list of requirements since I have to be a little flexible.

Bare minimum would be the following (over and above "standard" sensors like crank position, coolant temp, air temp, MAP, etc):
Ability to control quad cam VVT
Sequential fuel and spark on eight cylinders
Dual DBW
Electric water pump control
Dual wideband with per-bank closed loop fuel control
CAN bus interface(s) for talking to the dash display, PDM, and ABS controller

I would also like to have enough ADCs left over to add some engineering sensors without needing any expansion boxes/additional dataloggers (for things like damper pots, brake pressure, wheel speeds, trans/diff temps, etc).

And regarding the trigger patterns, most VVT implementations I've seen require you to pick from a list of canned trigger wheel and offset configurations. Since no one (to my knowledge) has ever actually used a B8444S VVT with an aftermarket ECU, it would be nice to not be beholden to the manufacturer to bake in that support.

I wasn't suggesting an ECU project, it's clearly not even close to capable of doing what you need at the moment I can see how it might have sounded a bit like that, though.

Now that I know what engine you're talking about, I'm curious about your intake setup, any idea which page that's on? The factory setup looks to have one giant throttle (per 2006 XC90 wikipedia photo).

I searched a bit but didn't find what sort of crank sensor setup you're using, however I did find a reference to making your own flywheel in another thread, but that other flywheel had no teeth cut into/out of it. The only reason I can think of to not have totally generic VVT code is multi tooth cam sensors. Anything single tooth should be merely configuration, at least in my architecture. Which would make the drop down box be a bunch of presets and a "custom" option. I guess this is how the Link works, probably.

Seems like a sweet engine, especially being a Yamaha design (I have some Toyota/Yamaha heads downstairs, very nice). May I ask how much it cost you? It'd be a great platform for development/testing for me at some point (though not soon, too many irons on the fire already).

The intake manifold has not been built yet. It will likely be a dual plenum design with two throttle bodies and some kind of crossover tube.

The trigger wheel is mounted on top of the ring gear, like so:


Sensor will be hall effect, mounted on the bellhousing. The trigger wheel is still a 60-0 since the sensor position and thus trigger offset angle hasn't been determined yet.

The cam trigger wheels are multi-tooth. There are two opposed teeth of different width. I don't have the detailed measurements on hand.

The first engine was $700 with a bad balance shaft bearing. The second engine was free and had a snapped timing chain. We also have a third engine with a bad balance shaft bearing. I don't remember what that one cost.

I'm a novice, and I might be missing something, but why not use an AEM Infinity?

Cheap as chips. Do you intend to keep the balance shaft(s)?

Interesting wheel design. /me goes back to lurking.

t8fanning said:

I'm a novice, and I might be missing something, but why not use an AEM Infinity?

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I haven't heard great things about the AEM ECUs when it comes to running engines that aren't explicitly called out as being compatible. Price is also a factor. The high speed logging and large on-board memory offered by the Infinity is very attractive though.

FreeEMSFred said:

Cheap as chips. Do you intend to keep the balance shaft(s)?

Interesting wheel design. /me goes back to lurking.

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The engine has a single balance shaft nestled in the vee of the engine. It is staying. No reason to remove it as far as I'm concerned.

Do you have any concerns about the trigger wheel? I've used thinner laser cut trigger wheels with a smaller OD in the past without issue.