SixStarCars' 818R - NASA ST3 - SCCA Solo X Prepared Build Thread

[Santiago]

What with the other gussets you added to the chassis, I'm surprised you didn't just add in another upper arm mount to put the control arm in double shear. I had considered this route, so I wonder what your thoughts would be.

Something like this is what I thought should be feasible with a couple of brackets and some trimming to clear the front roll-cage strut: single position upper a-arm mount
Or this: upper a-arm mounting bracket

I figure such a mod is at least as strong as what FFR is expecting R-cars to run and should be a good deal stronger.

Thoughts?

-j

[SixStar]

We're way too far off from any real testing, and I don't think the cars that are finished will be racing at our level.

We will just have to wait and see. I talked to several people about it and we're for sure NOT moving the upper arm.

[Jim Schenck]

Moving the lower arms up to the alternate ride height but not moving the uppers would give some pretty undesirable results with the front roll center. This would most likely (depending on ride height and tire size) give you a higher roll center in the front than rear and make the car pitch toward the rear in hard corners which is not what you want for sure. Mounting the upper arm to only the top plate would be plenty strong, that is how all MKI-MKIII cars were from FFR including the challenge cars, and those are about 400lbs heavier than the 818. Adding the spacers and using the strength of both plates is overkill strength wise, but since the mount is there we recommend using it.

[SixStar]

Haven't touched the 818R in a week!!!

Been busy with an ASP build for a friend/customer:
pw0XQqQ.jpg

But... this came today:
Z3ePJs7.jpg

2 and 2.5" IC piping from CX racing. They sent the core too but it was WAY too big. Steel for the rear hoop will be here tomorrow also. That means another trip to CORaceFab and another Friday/Saturday of custom fabrication and making this racecar a racecar.

Stay tuned!

[SixStar]

Got the rear body panels mounted solid enough for this next round of fabrication. All the materials are here and I'll be towing it over to Nayr's shop tomorrow for some work. Goal is to knock out the wing mount, intercooler and mount, IC piping, exhaust, and maybe the stand-offs for the quick release for the roll pan (rear bumper).

Lots to do but if we can bust it out then she's ALMOST ready for paint.

Album of today's work - http://imgur.com/a/djlH0#0

The fender liners need love in the front, they're a little flimsy. I'm hoping the sealing trim and some persuasion will make them fit better later on at final assembly.

[Racebrewer]

Cute pup. He looks as helpful as my deaf white cat.....<LOL>

Passing thought......... From my experience in square back, bluff bodies in road racing karts, the air behind the back panel is actually a high pressure area. Air comes around the sides and loops in a 180 degree turn. It might not ventilate as you want. I tried running orange yarn to follow air flow and it flowed over the top corner of the body and did a complete turn into the rear panel.

John

[SixStar]

Yeah, I've seen that on other cars. I'm hoping that there's enough 'filling' the rear body work from the 4 vents to create a pressure differential and since that will be the only exit air should flow over the IC. Plus since there isn't a windscreen or a roof on this car it won't behave the same as a full bodied car.

Air flow data would have been helpful, but since that won't happen I'm just going to build the thing and hope for the best. I do know for certain that the air "flow" over the TMIC will not be sufficient. I also know that an A2W is more complicated than I am comfortable with in a true racing situation.

Testing will just be ad-hoc until we're able to get it in a tunnel in late June.

[SixStar]

Got pretty far on the rear-subframe/intercoolermount/wingmount this weekend. I'm holding off on posting until it's mostly finished, it'll keep the "constructive criticism" at bay until it's done.

The very first thing we had to fix first was the badly warped rear strut bar. When the diagonals were welded on it shrunk warping either end of the flat bar up almost 1/2". This was the same on both frames and both bars. Solution one was to heat it up with a torch and massage it back into shape. We chose option two which was to notch the flat bar and kink the entire brace. Stronger, plus it actually looks pretty sweet with that slight raise in it.

P1181344.JPG

[SixStar]

We're using STI LCAs on our 818R but one of them is bent so we have a WRX LCA as a place holder and I can show everyone just how much caster you get from the STI arms.

WRX LCA using stock (worn out even) 205/55-16 tires, clear contact a ways before lock
P1171337.JPG

And here's full lock, same wheels and tires but with an STI LCA
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[SixStar]

Here are some pictures of our rear wing mount and intercooler. There are more but I wanted to get these up since a ton has been done since my last update.

Raw IC core


Rear tower bar plating, before clean-up

[SixStar]

Intercooler mounted and hot side tank done and plumbed in




Wing/IC mount attachment to the rear tower bar


Raw exhaust flange waiting for awesomeness

[Rasmus]

Keep up the great work Six.

I'm following your build, avidly. Thanks for all the great pictures.

[apexanimal]

^ ditto... great stuff here.

[Bob_n_Cincy]

I love your rear mount inter cooler and rear bumper and wing mount combination.
Bob

[nkw8181]

one word. NICE!!

[Brando]

Quick question on the usage as a bumper.
I really like the idea of protecting the trans and curious if you think your current addition will protect it when someone bumps into you or is it too high?
Are you going to add anything more to protect the trans or is the function really more geared for the IC and wing?

[Santiago]

Looks high to me to serve as protection for the trans. Besides, you would probably want separate components for separate functions.

C.Plavan has pointed this out a number of times. One set of bars for aero mounting, one set for bumper/trans protection. Those should NOT be incorporated into the wing mount, because if they are and you get tapped nicely you run the risk of altering your wing position in the process. Better to have a wing mount that is less likely to get distorted from a mild racing incident so you can finish the race with your normal level of aero performance intact.

Having said that, I've seen some high-level builds (a Ferrari Challenge car) use the trans bars as the base for the wing mount. However, in that configuration it was built like some sort of tank battering ram, so I suspect the idea was that if it's hit hard enough to move them, you're race is likely over anyway. I'm not sure I want to use that strategy. I'd prefer a more sacrificial set up that can take a mild tap w/no drama, take a hard tap and bend a bit w/o messing up my aero, and take a hard hit while yielding enough to disperse energy. The "battering-ram" style also weighs a lot since it needs to be overbuilt. We're also dealing with a different chassis starting point than the Ferrari, which means long bars extending out far enough, and for battering ram duty these need to be super beefy, etc., etc.

I think Plavan has in mind what I do - green flag drops, everyone heads for T1, there's a cluster-F*, and you get tagged from behind. Race just started and now your wing is all jacked up. No need for that. You should be able to carry on, not park it. Time enough for simple repairs at the shop.

My $0.02

Best,
-j

[Rasmus]

To me it looks like SixStar added that hoop there for a place to mount the intercooler, not as crash protection.

[VD2021]

Looks high to me to serve as protection for the trans. Besides, you would probably want separate components for separate functions.

C.Plavan has pointed this out a number of times. One set of bars for aero mounting, one set for bumper/trans protection. Those should NOT be incorporated into the wing mount, because if they are and you get tapped nicely you run the risk of altering your wing position in the process. Better to have a wing mount that is less likely to get distorted from a mild racing incident so you can finish the race with your normal level of aero performance intact.

Having said that, I've seen some high-level builds (a Ferrari Challenge car) use the trans bars as the base for the wing mount. However, in that configuration it was built like some sort of tank battering ram, so I suspect the idea was that if it's hit hard enough to move them, you're race is likely over anyway. I'm not sure I want to use that strategy. I'd prefer a more sacrificial set up that can take a mild tap w/no drama, take a hard tap and bend a bit w/o messing up my aero, and take a hard hit while yielding enough to disperse energy. The "battering-ram" style also weighs a lot since it needs to be overbuilt. We're also dealing with a different chassis starting point than the Ferrari, which means long bars extending out far enough, and for battering ram duty these need to be super beefy, etc., etc.

I think Plavan has in mind what I do - green flag drops, everyone heads for T1, there's a cluster-F*, and you get tagged from behind. Race just started and now your wing is all jacked up. No need for that. You should be able to carry on, not park it. Time enough for simple repairs at the shop.

My $0.02

Best,
-j

?..

[Scargo]

I think it needs to be lower AND built like a tank. I've seen too many videos lately about high-speed rear-end racing crashes.

Seems the tube that's in there now could be lighter, or nonexistent, with the tube moved below the intercooler and supporting it.
If you had crushable brackets and enough hose flex, the intercooler might even survive a rear impact and not loose pressure.
I'm going with AWIC even though it adds complexity.

[SixStar]

Clearly our design deserves some explanation.

The .083 wall chromoly tubing is in NO WAY designed as crash protection. It is a mount for the wing and intercooler.

We're not concerned with protecting the transmission. IMO if you get hit hard enough to cause damage to the trans your day is over. You'll need a new rollpan (rear bumper), shift linkage, rear diffuser, intercooler, etc. Putting a bar there will just cause more damage, if you mount it to the frame then when you get hit you now need a frame, I'm going to pass on that.... Plus you're transferring energy into a structure to which YOU are mounted, that's a recipe for getting hurt.

The engine and trans are mounted with Group N rubber mounts, they will give a little, they will shear off if hit hard. There isn't any more room in the back of these cars, there's less than a 1/4" between the shifter and the rollpan and maybe 4" tops between the pan and the transmission. It's a tube chassis fiberglass car, if you get hit it's going to be destroyed. Don't get hit.

[metalmaker12]

I agree to all points. Nice idea for mount

[tmoretta]

Yes, but how about a street car? Wouldn't it be sensible to have some sort of trans. protection in the event of a parking lot bump to the rear?

[07FIREBLADE]

Simple fix for that back your car into the space and dont hit anything

[SixStar]

The car is inherently fragile. The tires are the last substantial part in the front before you get into 4' of glass and tin. Correct me if I'm wrong but part of the allure of a kit car is that it's basically an engine on wheels that has a seat without all the nanny bits you get with a road car.

[Scargo]

Wow. I'm just not in agreement on hardly any of this. It defies (my) logic. An R has to meet NASA and SCCA cage requirements. Our use of the term fragile may be different, but the car isn't unsafe or weak. To say, "don't get hit" isn't realistic. Having a rear impact go straight into the tranny and engine means it's going to end up in your back and perhaps your fuel cell. I certainly will sacrifice my whole car before my body.

[Santiago]

Wow. I'm just not in agreement on hardly any of this. It defies (my) logic. An R has to meet NASA and SCCA cage requirements. Our use of the term fragile may be different, but the car isn't unsafe or weak. To say, "don't get hit" isn't realistic. Having a rear impact go straight into the tranny and engine means it's going to end up in your back and perhaps your fuel cell. I certainly will sacrifice my whole car before my body.

Agreed...so much agreed...

This is Six Star's build thread, so rather than further muck up his space maybe we should take up the matter of "rear impact solutions" in a separate thread.

The last I'll say of it here is that we all have our own sense of what risk we're willing to take on, so we should expect that each of us is going to prioritize what we do differently. However, acknowledging a risk and ignoring a risk are not merely different risk management strategies, since one seems to admit of individual judgment while the other seems reckless.

Best,
-j

[SixStar]

So you're saying that FFR is selling and racing unsafe cars?

Their car is NASA legal, no issues. You're aware that ALL safety rules are in place to keep the driver safe right? It's a car, it's made of parts, if those parts get damaged you can replace them. If you get damaged it's a bit tougher to just replace, say a spine.

Again, any accident that can do enough damage to "go straight into the tranny and engine means it's going to end up in your back and perhaps your fuel cell" isn't going to be solved by a simple bar across the back of the car. This isn't NASCAR....... I'm not sure you realize how much TT drivers stay out of each others way when on course.

In the end Santiago is right, it's my car and my build and the beauty of that is I can do what I feel is right. On top of that, everyone is entitled to their own opinion, even if it's wrong.

[Scargo]

So you're saying that FFR is selling and racing unsafe cars?

Their car is NASA legal, no issues. You're aware that ALL safety rules are in place to keep the driver safe right? It's a car, it's made of parts, if those parts get damaged you can replace them. If you get damaged it's a bit tougher to just replace, say a spine.

Again, any accident that can do enough damage to "go straight into the tranny and engine means it's going to end up in your back and perhaps your fuel cell" isn't going to be solved by a simple bar across the back of the car. This isn't NASCAR....... I'm not sure you realize how much TT drivers stay out of each others way when on course.

In the end Santiago is right, it's my car and my build and the beauty of that is I can do what I feel is right. On top of that, everyone is entitled to their own opinion, even if it's wrong.

I don't want to get in a pissing match over this and I don't see that I need to say more about it after this.
First, there's many ways to build, modify, place components and accessorize this kit car. What's "best" or even "better" will be debatable. So, I'm in complete agreement with you that everyone's entitled to their own opinion.

I want to be clear that YOU implied it was unsafe, NOT ME. You said, "The car is inherently fragile." "...it's basically an engine on wheels that has a seat without all the nanny bits you get with a road car." "if you get hit it's going to be destroyed." Referring to it as "tin" is a slur in the US when referring to a car. I said, "An R has to meet NASA and SCCA cage requirements.", so I am well aware that the 818R was approved to race by NASA. I was there. But NASA nor SCCA makes you build a crash-safe car in every respect. They don't inspect welds and they generally don't care about the efficacy of the design beyond some basic parameters and overall fit and finish. In other-words they won't let you race in a rust bucket that has mechanical issues.

I have never said anything about the 818 being unsafe. I said if it were me I would build it like a tank. Just recently there was a horrific wreck at the 24 hours at Daytona. That's what I think about, and the fact that I sustained a high-speed crash when I had a mechanical failure on the track. Not that there's anything wrong with the 818R frame; I'm just going to beef it up, and a little differently. With my N motor mounts, there's nothing in their design to stop the motor if they tear apart from a rear-end collision. I'm going to look at a way of restraining the engine and transmission a little better.

You've done a lot of neat and innovative things with your build. I don't mean to be disparaging about your project and certainly not you as a person. I was trying to contribute another opinion on what I think is an important issue.
I think that's why we are on here. I think we're using the forum to share and learn together so that we all have a better experience with our builds. I haven't even started yet and I've gotten a lot of critical comments that have helped me to better understand some things. I expect I'll get a lot more criticism before it's over for all my wacky ideas!

[SixStar]

You COMPLETELY misunderstood almost everything I wrote.

This is not an 818R
rFtTr8p.jpg

This is the CHASSIS and running gear for an 818R and is NASA legal and safe for the driver and passenger. This is strong.

This is an 818R (unfinished of course)
BeJIozc.jpg

It is flimsy, weak and lightweight, just like a Lotus or a Vette. Under it's fragile veneer of fiberglass and aluminum paneling (what I call, tin) is the CHASSIS of the 818R which is strong and safe.

[SixStar]

3wbvNlx.jpg

Got the differential for the 818R today. Going to pick the car up from fabrication, phase one is done.

On to body mounting and finishing the brake likes. Another 818 owner is being so kind as to let us borrow his fuel tank since it would appear we're not getting ours anytime soon.

Pictures of the exhaust and intercooler final setup Monday.

[Rasmus]

Ah, the "WRX" brand of helical gear limited-slip differentials. Good brand. /sarcasm

Seriously, what is it? Why'd you select that one over others?

[SixStar]

Ha ha, right? Looks as Chinese and generic as a junk OBX. It's a Modena torque biased differential. Their diffs and gear sets can be found in some of the top finishers in tiny, low budget racing like the Rolex 24, and the Porsche Cup.

Mostly because the guy behind Guard Transmissions is a long time Subaru guy, and a personal friend. Plus he's local in Colorado. Also this is the last new Modena TBD in existence, they will never make another.

[Scargo]

This diff? Says, "This is Modena's Torsen Style Torque Biasing Front Differential for the 2002 - 2007 WRX. This replaces the factory open differential, and will behave much like the factory LSD that is in the rear differential, or like the front LSD that comes in the STI from the factory."

Obviously you didn't buy it over a stock LSD just because it was expensive. Care to share the bias you chose to have in it? Why did you choose it over the clutch-pack styles in some of the better LSDs out there?

[C.Plavan]

I have the Modena in my R. Same as above. Not cheap Chinese crap. A great reputation from what I hear. I got it from the same Fella. I have been using his LSD's in my Porsche racer for years. He recommended it to me too.

Just curious, why do you need the stock fuel tank?

[SixStar]

This diff? Says, "This is Modena's Torsen Style Torque Biasing Front Differential for the 2002 - 2007 WRX. This replaces the factory open differential, and will behave much like the factory LSD that is in the rear differential, or like the front LSD that comes in the STI from the factory."

Obviously you didn't buy it over a stock LSD just because it was expensive. Care to share the bias you chose to have in it? Why did you choose it over the clutch-pack styles in some of the better LSDs out there?

Yep, that's the critter.

I've run Cusco, KAZZ, Quaife, and some factory viscous LSDs and for strength, tuning, and durability the TBDs can't be beat. The factory STI TBD isn't compatible with a USDM 5MT transmission. The theory is exactly the same though.

As for our R the only real choices (IMHO) were the Q and the Modena. I like Matt, I respect his opinion and having seen what these parts can do in real road racing situations in the Porsches sealed the deal. In the end it wasn't quite double the price of the Q but looking closely at the Modena it's definitely better quality.

As for clutch type LSDs, they require too much tuning for what we're after and on this application you're looking at several hours each time to remove and adjust the setup. Plus all clutch type diffs will wear out and need servicing whereas the TBD really won't unless you're abusing it for millions of miles.



I need the stock tank to finish my brake and clutch lines. We're still waiting for the official word from NASA about using the Boyd's tank which we've considered, but it would still need to be cut apart and have baffles welded in so..... not 100% sure what direction we're going yet. Long way off from needing it full of fuel still.

[Brando]

I just got my Boyd tank today and reading this was disheartening. So I just purchased a $600 tank that wont be NASA approved without ripping it apart. How can that be right

[C.Plavan]

I just got my Boyd tank today and reading this was disheartening. So I just purchased a $600 tank that wont be NASA approved without ripping it apart. How can that be right

Why would you think the Boyd Tank would be racing legal? No rubber bladder, not FIA certified. No where does Boyd claim any of that.

If you look (search) at a few threads going on, you can see the search and opinions on finding a correct race legal cell. I'm throwing a Fuel Safe in the passenger area. Better balance, and far, far away from the motor and headers.

I'm sure you can sell it quickly and recoup your money.

[longislandwrx]

I'm waiting to see what the price quotes come in at for a legal stock location tank, if its $1600 i'll pass and do what plavin is doing, passenger seat location.

Step 1 remove passenger seat

Step 2 bolt fuel cell to seat rails

Step 3 pump fuel from main tank to cell, move line from stock tank/surge tank to cell


an ed112 tank should be a good fit/cheap option.

[SixStar]

Boost piping is done. Exhaust is done.

P2201386.JPG

P2201387.JPG

P2201388.JPG

P2201389.JPG

V-band flange for quick change exhaust allowing us to run a muffler at SCCA Solo events and on the street and a straight pipe for the track
P2201390.JPG