Brunton Stalker XL #22 Build

[toedrag]

Major milestone achieved with the throttle linkage. Man, I struggled with this one...so many dependencies and chicken/egg scenarios trying to get it put together.

 

For some background, the LS3 uses drive by wire, and the GM throttle pedal is included in the electronics kit from Brunton. The GM pedal base is too large for the footbox, so it gets located on the vertical section of the firewall shelf, and there is a linkage connecting it to the actual pedal, both of which are also provided by Brunton - sort of. The DIY part here comes when connecting the GM pedal to the lever included in the Brunton kit. Brunton started using heims & hex tube on their turnkey cars, but these bits aren't included in the kit. The other common approach is to just use flat steel bar. I like the heims & hex tube approach, but had another idea, which was born mostly out of impatience and not wanting to source tiny hex tube & tiny heims.

 

I made up some clevis ends by bending some flat steel, tapped a 1/4-28 hole to use with some threaded rod, and drilled a 1/4" hole for the pin. I made two of these:

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27596&g2_serialNumber=3

 

Here is a partially assembled linkage, minus the cut-out in the firewall shelf to allow the Brunton-supplied pedal to pass through. I have 1/4" bolts as the 'pins' of the clevis, temporarily. Locating the connection point high on the GM pedal allows a nice stock feel to the throttle pedal effort and should still clear the underside of the hood. I used bronze sleeves as thrust bearings (I think that's the term?). And yes, the ECU harness can still be easily connected with the pedal base mounted where it is.

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27598&g2_serialNumber=4

 

Final throttle pedal position. All pedals are quite adjustable. When I climbed in and practiced my heel/toe, it felt good, but I was really guessing on the amount of brake pedal travel the car will have:

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27600&g2_serialNumber=3

 

Top view of the near-final assembly. What's not shown is some temporary reinforcement on the other side of the firewall shelf where the GM pedal base mounts. The firewall shelf flexes a little too much for my liking when the pedal is actuated. I have yet to figure out exactly what I'll do back there, but it shouldn't be too difficult.

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27604&g2_serialNumber=5

 

To finish things up:

• I'll add some nylon spacers to the clevises to keep them quiet
  
• Lengthen the pedal cut-out to allow slightly more pedal travel at the end of the stroke
  
• Add a grommet/boot for the cut-out in the firewall shelf
  
• Figure out reinforcing for GM pedal base
  
• Cut-off the extra GM pedal
  
• Add a 1/4" pin/bolt to connect the throttle pedal to the linkage lever. There is only 1 sheet metal screw holding it in right now, and I'm not going to rely on that to keep my throttle pedal attached.
  

[jevs]

That is a bit different angle/throw than they use at the cut off GM throttle pedal. Curious if your planning to leave it there and like it better?

 

I am working on gathering the parts for this. Sourcing a 3" rod for the heims is not fun (hard to find, but I did find it). I asked Scott if he can just sell me the heims and rod instead since they have to send me some parts soon anyway. I am waiting for a response to that. The extra adjustability might come in handy later, who knows.

 

I also ordered those same spacers you used on the other pedals to avoid all the time wasting of making my own. I had a 15% coupon code for garage sale items so it was like $8.49

[toedrag]

That is a bit different angle/throw than they use at the cut off GM throttle pedal. Curious if your planning to leave it there and like it better?

 

I am working on gathering the parts for this. Sourcing a 3" rod for the heims is not fun (hard to find, but I did find it). I asked Scott if he can just sell me the heims and rod instead since they have to send me some parts soon anyway. I am waiting for a response to that. The extra adjustability might come in handy later, who knows.

 

I also ordered those same spacers you used on the other pedals to avoid all the time wasting of making my own. I had a 15% coupon code for garage sale items so it was like $8.49

 

It is; I do like it and will leave it - unless something else with the remainder of the car requires me to do something different. It's as close to the feel of a "stock" pedal as I could get. The other location doubles or maybe triples the amount of effort required to move the pedal. I'm guestimating; I'm sure there's some math I could use here, but I don't feel like looking it up. I suspect the closer location may be based on Scott's personal preference to have a very stiff throttle pedal.

 

The good news is that, as long as you don't chop off the end of the pedal first, you can drill a few holes to find what you like :cheers:

 

The adjustability is useful for changing the angle/distance of the throttle pedal relative to the other pedals - if nothing else for the initial setup. I probably adjusted mine 5-6 times, and I imagine I'll adjust it a couple more times after I have a functional vehicle.

[toedrag]

Oh, I also forgot to mention a conversation with Scott several days ago where I was asking about the general approach for the throttle pedal installation. In the course of that conversation, he mentioned that if the pedal was too stiff, remove one of the springs from the pedal base. At the time, I didn't really understand why he suggested it, but now I do.

 

This said, this convo was well before I actually started my throttle pedal install, and I haven't discussed my exact implementation with Scott.

[toedrag]

Okay, one more call-out: with the different mounting points on the GM pedal arm, it changes the amount of available throttle pedal travel. So, it's a tradeoff of effort vs how much travel you want.

[JohnCh]

The firewall shelf flexes a little too much for my liking when the pedal is actuated. I have yet to figure out exactly what I'll do back there, but it shouldn't be too difficult.

 

One option is to get a wide piece of thicker aluminum stock, bend it into a bracket that matches the scuttle back-bottom angle, and then attach both throttle assemblies to it. You could also weld in some webbing for added strength or to simply allow use of thinner aluminum. Shouldn't add too much weight and will help keep the relationship between the two throttle assemblies pretty rigid.

 

-John

[toedrag]

One option is to get a wide piece of thicker aluminum stock, bend it into a bracket that matches the scuttle back-bottom angle, and then attach both throttle assemblies to it. You could also weld in some webbing for added strength or to simply allow use of thinner aluminum. Shouldn't add too much weight and will help keep the relationship between the two throttle assemblies pretty rigid.

 

-John

 

Thx, John. That's a good idea. I was thinking something along those lines, maybe using 2 pieces of aluminum angle with a support between the two.

[xcarguy]

. . . . The adjustability is useful for changing the angle/distance of the throttle pedal relative to the other pedals - if nothing else for the initial setup. I probably adjusted mine 5-6 times, and I imagine I'll adjust it a couple more times after I have a functional vehicle.

 

Brit,

 

Looking great!

 

This is more for all the Storker builders; keep in mind that the shorter the travel of the throttle pedal (shorter throttle pedal arm in relation to the push rod location) the less progressive the throttle will be. You NEED relatively 'long' (progressive) throttle pedal travel or the car (with an LS engine) will be pretty much un-drivable. Ask me how I know this. :jester:

[subtlez28]

This is really cool to see. I wish you guys had built your kits first.

 

I really struggled with pedal placement also. And, like you had difficulty sourcing a heim set up small enough. I wish Brunton would include those parts in the kit.

 

Anyway, my set up also came from impatience, and just wanting to drive the car. A simple flat piece of (scrap) aluminum connects the pedal to the DBW set up. I intend to replace it with adjustable heims down the road, but it works for now.

 

I was concerned about flexing the shelf also. The DBW pedal required a lot of force! I cut one of the springs off.

 

I'm not sure that was a good idea now though. I was told from the start, that a lot of pedal travel was key to getting the LS3 power to the ground. So with the ratio, and mechanical advantage, the pedal is a bit to easy to push.

 

All the travel also means I'm not 100% satisfied with pedal placement from a heal/toe perspective.

 

More find tuning for the off season!

 

Keep up the great build thread! You are quite a craftsman.

[toedrag]

Brit,

 

Looking great!

 

This is more for all the Storker builders; keep in mind that the shorter the travel of the throttle pedal (shorter throttle pedal arm in relation to the push rod location) the less progressive the throttle will be. You NEED relatively 'long' (progressive) throttle pedal travel or the car (with an LS engine) will be pretty much un-drivable. Ask me how I know this. :jester:

 

Excellent point! Thx for bringing this up.

[toedrag]

Progress on the support brackets for the GM pedal base. Here's a couple videos to illustrate what's happening. In all of these videos, I'm pushing on the throttle pedal in the foot well.

 

This first video is with no brackets for the GM pedal base and with the scuttle installed, i.e. the default configuration if I left it alone and continued on with other parts of the build:

 

As you can see from the above video, there is enough flex that small throttle pedal modulations are absorbed by the aluminum panel, which isn't good.

 

Now, the next video - for entertainment purposes - this is what happens when you remove the scuttle:

 

That is a ridiculous amount of movement, but obviously, since no one would ever operate the car like that, it's not a valid use case. Still, it illustrates what's happening.

 

Here's my first attempt at solving the problem. I made 2 brackets out of 1/16" thick aluminum angle from my local HW store. I cut a slit, bent the angle, put a sheet metal screw in to lock things down. For one connection point, I used a 1/4-28 bolt with three washers, which you'll understand why shortly. These then attach to existing holes I had in the tunnel top & frame tubes.

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27614&g2_serialNumber=3

 

Here's how I modified the GM pedal base. The GM pedal base comes with only 3 holes, but only two are usable as-is: top right and bottom left. To use the top left hole, I used a 1/4-28 tap, and then used a 1/2" bolt with 3 washers to prevent the bolt from protruding too far. If the bolt extends beyond the face of the base flange, it acts like a stop and prevents the GM pedal arm from reaching full throttle.

 

I drilled a new hole in the bottom right.

 

Now, the pedal base has 4 usable connection points.

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27618&g2_serialNumber=3

 

The resulting video, with the brackets installed but without the scuttle. It's a dramatic improvement, and the throttle modulations are transferred to the GM pedal arm, even though there is still a tiny bit of flex remaining. Refer back to the previous video to be reminded how terrible the flex was without the brackets and without the scuttle:

 

So, it seems clear to me that something needs to be done. I think my brackets are acceptable (not pretty, but they'll be masked by the scuttle), but what might be better is a little steel tab welded in the corner of the upper frame tubes, just under the tunnel top, which would allow both brackets to have a better angle for resisting the flex. I'll have to add this to my "needs welding" list since I don't weld.

 

What is also now apparent is that the Brunton-supplied bracket it also moving a tiny bit. I'm referring to the piece shown in the lower left corner of the videos above, and if you look closely, you can see it moving in the videos. The two near side holes (not pictured in the videos) of this bracket are drilled through the frame, but the far side holes (you can see the two clecos in the last video) are only attached to the firewall shelf. At full throttle, that far side of the bracket dips down 1/16" or so. I'm thinking another steel tab should be welded over there to support it. I could just do some right-angle brackets temporarily, but I don't feel like drilling unnecessary holes in the frame.

 

Open to other ideas on this too, of course.

Edited October 2, 2014 by toedrag

[jevs]

I know you already made your own link and probably don't want to go backwards, but I found and ordered what should be a suitable part available in a short length for the throttle.

 

http://www.bmikarts.com/Racing-Aluminum-Tie-Rod-Kit-38-24_p_1492.html

[toedrag]

I know you already made your own link and probably don't want to go backwards, but I found and ordered what should be a suitable part available in a short length for the throttle.

 

http://www.bmikarts.com/Racing-Aluminum-Tie-Rod-Kit-38-24_p_1492.html

 

Good find. It does look much nicer than mine. The Brunton lever is only 5/8" OD though...a 3/8" hole through it seems like it might be too large. I may look for a 1/4" one.

[jevs]

I believe 3/8 is what Brunton uses. If you think the bolt is too large though, you can simply get a shoulder bolt with smaller thread, or put a little sleeve in the hole of the heim for a smaller bolt. The 3/8" hole gives you options. You could use 3/8", 5/16", or 1/4" bolts. If you use 1/4, well, then you just have to use 1/4, which may be fine. I am not sure how much force/tension is on this stuff yet. I am not as far along as you.

 

It does look like if you press on the pedal hard ("flooring it :)" ) that the bolt will have to take that force. Nothing on the pedal setup before the rod has a stopper that I know of yet. Bottoming out the GM cutoff pedal is the stopper I believe.

 

That rod is aluminum too, which gives you a little tiny weight savings and no rust. Not sure about the ends. I would assume they are steel by the picture.

[toedrag]

I believe 3/8 is what Brunton uses. If you think the bolt is too large though, you can simply get a shoulder bolt with smaller thread, or put a little sleeve in the hole of the heim for a smaller bolt. The 3/8" hole gives you options. You could use 3/8", 5/16", or 1/4" bolts. If you use 1/4, well, then you just have to use 1/4, which may be fine. I am not sure how much force/tension is on this stuff yet. I am not as far along as you.

 

It does look like if you press on the pedal hard ("flooring it :)" ) that the bolt will have to take that force. Nothing on the pedal setup before the rod has a stopper that I know of yet. Bottoming out the GM cutoff pedal is the stopper I believe.

 

That rod is aluminum too, which gives you a little tiny weight savings and no rust. Not sure about the ends. I would assume they are steel by the picture.

 

Ahh, I see. Makes perfect sense. Thx for clarifying.

 

The only other pseudo-stopper in play is the oval cut-out in the firewall shelf, but since that will flex with force applied, it's not a very good stopper. I was thinking about adding both a clutch stop & throttle stop.

[subtlez28]

I know you already made your own link and probably don't want to go backwards, but I found and ordered what should be a suitable part available in a short length for the throttle.

 

http://www.bmikarts.com/Racing-Aluminum-Tie-Rod-Kit-38-24_p_1492.html

 

I was ll set to order one of these to replace my temporary aluminum linkage. But my linkage is ~4.75" center to center, so the kits start to large for me.

 

What lengths are you guys seeing?

[jevs]

Brunton said a 3" rod. I see in their picture there was plenty of exposed thread on the heims. So, I assume the smallest 3-1\8" rod would work for me, so that is what I ordered.

 

Any shorter and the heims will hit each other inside the tube I think.

 

You could probably buy that smallest one and then trim the end of the rods and the threads of the heims if needed.

Edited October 3, 2014 by jevs

[toedrag]

I was ll set to order one of these to replace my temporary aluminum linkage. But my linkage is ~4.75" center to center, so the kits start to large for me.

 

What lengths are you guys seeing?

 

On mine, at the lower mounting point on the GM lever, it's [Correction]about 5 1/4" and with the upper mounting point, it's 6 1/4"

[toedrag]

Been ordering a few small parts here, like sensors & adapters.

 

Preparing for drivetrain installation, I had to modify my build table to raise the lower supports so that the engine hoist's legs could fit underneath.

 

I also finally took inventory of the suspension bolts I want to swap out, measuring the proper grip and looking up cost & part numbers for AN bolts, nuts, & washers. I'll add my list of AN bolt p/n's & locations once I've verified that they are correct installed in the car. The total cost came in at ~$150, which was less than I thought it would be. It may be overkill, but I view it as a cheap insurance policy. I'll sleep better at night.

 

I also finally spent some quality time with the engine for the oil pan swap. I was surprised that the engine was shipped with a full sump...but hey, draining it was pretty darn easy.

 

Starting off, here are a few of the oil-related parts going in:

 

• LS3 Corvette Oil Pan, GM p/n 12624617
  
• LS3 Corvette oil pickup w/new o-ring, 12624497
  
• LS3 Corvette dipstick (12570788), and dipstick tube (12570787). In retrospect, the dipstick & tube that came with the engine could work fine, but I went ahead and swapped it anyway
  
• Improved Racing crank scraper & oil pan baffle (EGM-215, which is now on their website here)
  
• CBM-10820. This is a little piece that replaces the oil cooler block off plate on the oil pan. It has 3 holes: 1 hole = M12 x 1.5 and 2 holes = 1/8 NPT. This is where one of my oil temperature sensors will go, and the other 2 holes will be plugged
  
• M20 x 1.5 to 1/8 NPT adapter. This will replace the stock oil level sensor in the pan, which is the light brown protrusion on the left side of the oil pan. The stock sensor has a float switch for the oil level indicator and also has a thermistor for oil temperature. However, I can tell you that GM's OEM ECU's only use it for oil level and use a calculation for oil temperature, not an actual sensor. I hypothesize this is because the plastic housing of the sensor isn't the best conductor of heat. I did some testing on this sensor a while back on another car, and it takes about 2 minutes, literally, for that thing to register a change in temperature. The GMPP ECU doesn't use the oil level sensor at all, and I briefly explored using it to connect to an indicator light. But, because the float sloshes about while the oil moves around, it means the sensor is constantly bouncing on-off repeatedly at a random rate. A non-GMPP ECU will have some debouncing logic and only alarm if the switch is off after some longer duration, like maybe 300ms, but I'm not going to go to the trouble of doing that. So, I'll remove the sensor, install this adapter, and have another 1/8 NPT oil temperature sensor.
  

 

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27623&g2_serialNumber=4

 

Stock oil pan removed:

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27626&g2_serialNumber=3

 

Stock windage tray removed:

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27628&g2_serialNumber=3

 

Crank scraper installed. This is my first time using a crank scraper. The provided instructions do a good job of explaining that you need to use a Feeler Gauge to measure the clearance between the crank scraper & crankshaft, while manually rotating the crankshaft. If the proper clearance can't be obtained by repositioning the crank scraper, it's time to get out the hand file. The recommended clearance is 0.020" to 0.060". I trimmed the scraper in 4 spots and re-checked the clearance after installation. The most annoying part about this was manually rotating the crankshaft.

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27630&g2_serialNumber=3

 

More on next post...

Edited October 7, 2014 by toedrag

[toedrag]

Oil Pan baffle & oil pickup installed. These were straightforward:

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27634&g2_serialNumber=3

 

C6 corvette oil pan installed, which comes with a new gasket riveted to the pan. I scraped off the old gasket maker goo in the corners of the block, all mating surfaces were cleaned, and applied new gasket maker in the corners, and the pan was aligned to the block per the service manual instructions:

http://www471.pair.com/stalkerv/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=27636&g2_serialNumber=3

 

Will do the sensors & adapters later on...

Edited October 7, 2014 by toedrag