Forums » Grassroots Motorsports » New guy to the Challenge 1 2

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  Aug. 7, 2010 11:47 a.m. rockthemullet None

  Well gents, with this being my first post I might as well start off with a bang. A few friends and I have decided to build a GRM Challenge car. 2011? Nope, 2010. Are we starting ridiculously late? Absolutely, but lets just call that another challenge we've given ourselves. We've already acquired the car (Aug. 1, 2010) and have laid out a pretty solid plan. There are a few concerns, however, and that leaves me to some questions...

  • I've seen some projects strictly gut the interior and be done with weight reduction while I've seen others literally cut sections out of the car (most of them are drivetrain swaps). Nevertheless, what exactly are the rules here? The Challenge rules dictate that all body panels and the unibody must remain intact unless modified for drivetrain clearances. If non structural areas are compromised by rust, can these areas be cut out and not replaced? Can sheet metal be removed for air intake system routing? If plastic inner fender wells cover metal inner fender wells, can either of them be removed? (Challenge rules state inner fender wells remain)

  • Which lexan and polycarbonate materials meets the Challenge safety requirements and which do not?

  • Challenge rules mention replacement of wheels and tires while additional wheels and tires must be figured into the budget. Does this mean the primary set of tires on the car (call them replacement tires for tires currently on the vehicle) are not added to the budget?

  • Some parts for the project have already been purchased. Contacting the previous owners may be possible but on certain things it may be difficult. Is it possible to use quoted prices on currently available parts to prove value of parts currently owned? My understanding is that this is correct but I wanted to clarify.

  With this being our first time out and with a very limited time frame, our only goal is to finish in the top half of the field. This is really just a "get our feet wet" exercise and a good stepping stone for future Challenge years. We're looking forward to it!

  ~Eric

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  Aug. 7, 2010 12:20 p.m. EvanB Dork

  If a certain part is not on the car at the challenge then it does not need to be counted in the budget. So if you replace the wheels and tires you don't need to count the ones currently on them if you don't use them at the event.

  I believe the inner plastic liners can be removed as long as the metal inner fenders remain.

  Formerly jdmae92

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  Aug. 7, 2010 4:29 p.m. AngryCorvair SuperDork

  EvanB wrote: If a certain part is not on the car at the challenge then it does not need to be counted in the budget. So if you replace the wheels and tires you don't need to count the ones currently on them if you don't use them at the event.

  not exactly. if they were covered by the initial purchase price of the vehicle, then you can not deduct them from the budget unless you actually sell them. file that under "challenge tribal knowledge".

  however, you are allowed to trade parts into and out of your personal stash, or the stashes of others, as long as the following two conditions are met: 1. FMVs on both sides of the trade are pretty equal; AND 2. the source of the thing you're trading hasn't been zeroed out in your budget.

  2 above is why i never zero anything out. sell it down to a dollar and you can trade until you die. sell it down to zero and no trading after that point.

  OK, i just re-read the OP's post, and while tires are probably considered safety items, you can't replace all-season whitewalls with V710s, unless it's a trade meeting conditions 1 and 2 above.

  if you're gonna be a bear.... be a grizzly bear!

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  Aug. 8, 2010 9:34 p.m. rockthemullet New Reader

  Thanks for your responses, gentlemen. I'm bumping this, hoping for more insight on the rest of my questions. I also have another for you...

  • Are we limited to the type of fuel we can use? 93? 91? E85? C16? 110?

  ~Eric

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  Aug. 8, 2010 9:44 p.m. unevolved HalfDork

  Fuel and all other fluids are non-budgeted and unlimited. We ran 109 in our car last year.

  Texas A&M Racing

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  Aug. 9, 2010 12:23 p.m. rockthemullet New Reader

  Excellent news!

  Pertaining to safety equipment, the rules state roll cages must be bolt in while roll bars can be welded in. Can the main hoop (technically a roll bar) be welded in and have slip fit female provisions for removeable, bolt in a-pillar and door bars? I would think this would satisfy the bolt in requirement but I'm not 100%.

  ~Eric

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  Aug. 9, 2010 6:17 p.m. SVreX SuperDork

  The main hoop is not a roll bar if it is part of a roll cage (bolt in or otherwise). It would then be a roll cage.

  Are you going fast enough to need a cage? They aren't required unless you are going faster than 11.50.

  Lexan- The Challenge does not have safety rules. The NHRA does, and the SCCA does. Challenge cars are subject to both. NHRA requires minimum 1/8" thick. Not sure about SCCA.

  I think you answered your own question on body panels, but you read it wrong. It doesn't say all panels must be intact,it says they must be present at all times on the car.

  Wheels and tires: Your question is confusing. The wheels and tires that were on the car when you bought it are included in the purchase price. If you sell them, you may recoup the value (up to the limit). If you buy tires for the car that were not on it when you bought it, the price goes in the budget. If you buy a second set of wheels or tires, the price also goes in the budget.

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  Aug. 9, 2010 6:51 p.m. unevolved HalfDork

  I believe there's a "commercially available" stipulation for the "roll bars are free" section.

  Texas A&M Racing

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  Aug. 9, 2010 7:02 p.m. SVreX SuperDork

  unevolved wrote: I believe there's a "commercially available" stipulation for the "roll bars are free" section.

  Nope:

  Rule G said: Roll bars and roll cages may be added. Roll cages must be bolted (not welded) into the automobile and contained within the passenger/driver compartment. Roll bars may be welded in. A roll cage has more than five attachment points (but no more than eight) to the body or frame. Roll bars and roll cages must be padded withing 6-inches of the occupants heads with SFI-spec high-density padding. Helmets must be worn in cars with roll bars or roll cages. Any additional bars and attachment points added to the roll bar or roll cage, or extending the bar or cage outside of the passenger compartment to the suspension pick up points will negate this allowance and make the entire cage count towards your budget. The safety items may only be used as intended for safety purposes and have no performance advantage.

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  Aug. 9, 2010 11:13 p.m. rockthemullet New Reader

  SVreX wrote: The main hoop is not a roll bar if it is part of a roll cage (bolt in or otherwise). It would then be a roll cage. Are you going fast enough to need a cage? They aren't required unless you are going faster than 11.50. Lexan- The Challenge does not have safety rules. The NHRA does, and the SCCA does. Challenge cars are subject to both. NHRA requires minimum 1/8" thick. Not sure about SCCA. I think you answered your own question on body panels, but you read it wrong. It doesn't say all panels must be intact,it says they must be present at all times on the car. Wheels and tires: Your question is confusing. The wheels and tires that were on the car when you bought it are included in the purchase price. If you sell them, you may recoup the value (up to the limit). If you buy tires for the car that were not on it when you bought it, the price goes in the budget. If you buy a second set of wheels or tires, the price also goes in the budget.

  It's possible that we will be skirting the edge on the 11.50 cert. I don't understand why it requests that roll cages be bolted in... if anything I would think that welded mounts would be preferred. I know neither NHRA nor SCCA discourages welded mounts so what is the concern here in the rules?

  You're other answers helped, thank you for the clarification!

  Rule G said: Roll bars and roll cages may be added. Roll cages must be bolted (not welded) into the automobile and contained within the passenger/driver compartment. Roll bars may be welded in. A roll cage has more than five attachment points (but no more than eight) to the body or frame. Roll bars and roll cages must be padded withing 6-inches of the occupants heads with SFI-spec high-density padding. Helmets must be worn in cars with roll bars or roll cages. Any additional bars and attachment points added to the roll bar or roll cage, or extending the bar or cage outside of the passenger compartment to the suspension pick up points will negate this allowance and make the entire cage count towards your budget. The safety items may only be used as intended for safety purposes and have no performance advantage.

  This is another concern. A roll cage has 6 or more attachment points but mounts rearward of the main hoop would be impossible in our car without running outside of the passenger compartment. I'm assuming the main hoop mounts, hoop support mounts, and a-pillar/door bar mounts would suffice.

  ~Eric

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  Aug. 10, 2010 6:56 a.m. Pat Reader

  rockthemullet wrote: It's possible that we will be skirting the edge on the 11.50 cert. I don't understand why it requests that roll cages be bolted in... if anything I would think that welded mounts would be preferred. I know neither NHRA nor SCCA discourages welded mounts so what is the concern here in the rules? You're other answers helped, thank you for the clarification! This is another concern. A roll cage has 6 or more attachment points but mounts rearward of the main hoop would be impossible in our car without running outside of the passenger compartment. I'm assuming the main hoop mounts, hoop support mounts, and a-pillar/door bar mounts would suffice. ~Eric

  You can weld a "cage" but GRM sees that as chassis stiffening, which is a performance advantage. If you weld it, you then have to apply the cost of the entire cage towards your budget.

  If you want to weld, you should consider doing a 5 point, which should be a main hoop, two rear down bars and the drivers door bar. As long as you meet the rest of the NHRA specs on tubing size and wall diameter, you'd then be NHRA legal to 10.00 or 135 mph. GRM allows a welded 5 point to be unbudgeted.

  On your second question, to be NHRA legal below 11.50, you'll need to run the rear down bars from the hoop, even if they are outside of the passenger compartment, like a pick up truck.

  Pat

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  Aug. 10, 2010 7:18 a.m. unevolved HalfDork

  SVreX wrote:

  unevolved wrote: I believe there's a "commercially available" stipulation for the "roll bars are free" section.

  Nope:

  Rule G said: Roll bars and roll cages may be added. Roll cages must be bolted (not welded) into the automobile and contained within the passenger/driver compartment. Roll bars may be welded in. A roll cage has more than five attachment points (but no more than eight) to the body or frame. Roll bars and roll cages must be padded withing 6-inches of the occupants heads with SFI-spec high-density padding. Helmets must be worn in cars with roll bars or roll cages. Any additional bars and attachment points added to the roll bar or roll cage, or extending the bar or cage outside of the passenger compartment to the suspension pick up points will negate this allowance and make the entire cage count towards your budget. The safety items may only be used as intended for safety purposes and have no performance advantage.

  Ah, I remember now. I was asking about the "extending outside the passenger compartment" phrase, as most all Miata roll bars I've seen require cutting into the rear deck to mount. The car's just too short to contain a properly triangulated bar within the passenger compartment, so Per said if it's a commercially available bolt-in 4-point, it's allowed for a Miata. It's somewhere in the rule thread.

  Texas A&M Racing

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  Aug. 10, 2010 8:29 a.m. Pat Reader

  unevolved wrote:

  SVreX wrote:

  unevolved wrote: I believe there's a "commercially available" stipulation for the "roll bars are free" section.

  Nope:

  Rule G said: Roll bars and roll cages may be added. Roll cages must be bolted (not welded) into the automobile and contained within the passenger/driver compartment. Roll bars may be welded in. A roll cage has more than five attachment points (but no more than eight) to the body or frame. Roll bars and roll cages must be padded withing 6-inches of the occupants heads with SFI-spec high-density padding. Helmets must be worn in cars with roll bars or roll cages. Any additional bars and attachment points added to the roll bar or roll cage, or extending the bar or cage outside of the passenger compartment to the suspension pick up points will negate this allowance and make the entire cage count towards your budget. The safety items may only be used as intended for safety purposes and have no performance advantage.

  Ah, I remember now. I was asking about the "extending outside the passenger compartment" phrase, as most all Miata roll bars I've seen require cutting into the rear deck to mount. The car's just too short to contain a properly triangulated bar within the passenger compartment, so Per said if it's a commercially available bolt-in 4-point, it's allowed for a Miata. It's somewhere in the rule thread.

  I don't recall the discussion around the Miatas, but if it's a 4 point, it's still not going to get you legal below 11.50. Per may allow it for safety, but it's not NHRA legal.

  Pat

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  Aug. 10, 2010 11:03 a.m. unevolved HalfDork

  I would love to have that legality issue.

  Texas A&M Racing

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  Aug. 10, 2010 1:01 p.m. SVreX SuperDork

  rockthemullet:

  I think I am hearing you say that you hope to be in the top 50%, but are potentially flirting with 11.50's.

  An 11.5 would generally put you pretty high in the running.

  So, either you need to tighten up and get the rest right so you can be in the top 10, or confess that you are an overly optimistic wishful thinker like the rest of us.

  Check the scoring carefully. If you are anticipating a top 50% finish, the point or two you could be penalized for not having a roll cage probably won't hurt that much. Autocross seconds count for a bit more than drag seconds.

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  Aug. 10, 2010 1:27 p.m. poopshovel SuperDork

  unevolved wrote: I would love to have that legality issue.

  +1.

  Build a man a fire, and he'll stay warm for a day. Set a man on fire, and he'll stay warm for the rest of his life.

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  Aug. 10, 2010 2:50 p.m. rockthemullet New Reader

  Pat wrote: You can weld a "cage" but GRM sees that as chassis stiffening, which is a performance advantage. If you weld it, you then have to apply the cost of the entire cage towards your budget. If you want to weld, you should consider doing a 5 point, which should be a main hoop, two rear down bars and the drivers door bar. As long as you meet the rest of the NHRA specs on tubing size and wall diameter, you'd then be NHRA legal to 10.00 or 135 mph. GRM allows a welded 5 point to be unbudgeted. On your second question, to be NHRA legal below 11.50, you'll need to run the rear down bars from the hoop, even if they are outside of the passenger compartment, like a pick up truck.

  Excellent reply, thank you! Regarding the rear down bars, does the length of the bar have a minimum? As in, could the bar be welded to the cabin side of C-pillar of the cab (if it was a truck, for instance). This would keep the whole system in the passenger compartment and satisfy the requirement.

  unevolved wrote: I would love to have that legality issue.

  poopshovel wrote: +1.

  Haha, shouldn't be too hard ;)

  SVreX wrote: rockthemullet: I think I am hearing you say that you hope to be in the top 50%, but are potentially flirting with 11.50's. An 11.5 would generally put you pretty high in the running. So, either you need to tighten up and get the rest right so you can be in the top 10, or confess that you are an overly optimistic wishful thinker like the rest of us. Check the scoring carefully. If you are anticipating a top 50% finish, the point or two you could be penalized for not having a roll cage probably won't hurt that much. Autocross seconds count for a bit more than drag seconds.

  Haha, well I'm more of a realist than an optimist and our combo has been proven for sub 11.50s. I guess we'll see where we stand in the pack at the event. Being my first, its really hard to determine where that will be.

  As far as I know the penalization for not being legal for 11.49 is that you are scored at 11.50. If, magically, someone (definitely not us) ran a 9.99 and wasn't legal past 11.50, it would be terrible to be crippled so badly by that mistake.

  ~Eric

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  Aug. 10, 2010 4:13 p.m. Pat Reader

  rockthemullet wrote: .

  Excellent reply, thank you! Regarding the rear down bars, does the length of the bar have a minimum? As in, could the bar be welded to the cabin side of C-pillar of the cab (if it was a truck, for instance). This would keep the whole system in the passenger compartment and satisfy the requirement.

  I don't think there is a minimum length, but I believe they are required to be attached the frame on a full framed vehicle or the the 6x6x1/8 plates welded to the floor of a unibody vehicle.

  Pat

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  Aug. 11, 2010 12:06 a.m. rockthemullet New Reader

  Pat wrote: I don't think there is a minimum length, but I believe they are required to be attached the frame on a full framed vehicle or the the 6x6x1/8 plates welded to the floor of a unibody vehicle.

  Well SCCA rules state:

  9.4.B.2.e On cars where the rear window/bulkhead prohibits the installation of rear braces (e.g. Honda del Sol), the main hoop shall be attached to the body by plates welded to the cage and bolted to the stock shoulder harness mounting points. This installation design must incorporate a diagonal bar connecting the top of the main hoop to the lower front passenger side mounting point (Petty Bar). Alternatively, the rear window may be removed and a clear, lexan replacement installed. The rear cage braces may pass through this replacement window and through the engine cover or bodywork to allow connection to the frame or unibody. Such allowances shall be noted on the car’s specification line.

  I can't access the NHRA rules. Does anyone know if they're similar? Thanks in advance.

  ~Eric

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  Aug. 11, 2010 1:14 a.m. NYG95GA SuperDork

  Don't worry about it. Tape it down with duct tape, and explain to your tech that it's welded under the tape, while you hand him a fifth of Maker's Mark.

  Proceed.

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  Aug. 11, 2010 6:46 a.m. SVreX SuperDork

  rockthemullet wrote: As far as I know the penalization for not being legal for 11.49 is that you are scored at 11.50. If, magically, someone (definitely not us) ran a 9.99 and wasn't legal past 11.50, it would be terrible to be crippled so badly by that mistake. ~Eric

  That is correct, but it is exactly my point.

  Since you won't be running 9.99, the penalty won't be much.

  Let's say you run an 11.2. You would be "penalized" 0.3 seconds in the overall scoring. That could easily be made up for by just finding a slightly better line in the autocross. And it will not likely mean a huge difference in your placement (is there really a big difference between being in 27th place or 22nd?)

  If you are not targeting the top 10, your time and money would be better spent in other areas. You'll make up more scoring in the overall by spending your time on adequate testing and tuning, or your money on a better set of tires.

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  Aug. 11, 2010 6:52 a.m. Pat Reader

  rockthemullet wrote: I can't access the NHRA rules. Does anyone know if they're similar? Thanks in advance. ~Eric

  There are a number of differences, including tubing diameter, wall thickness, mounting plate attachment, etc. Which way you go depends on where you think the car will need the bar. For example, an SCCA spec bar isn't going to make you legal past 11.50. I

  There's a diagram here for the NHRA specs.

  http://www.nhraonline.com/contacts/tech_faq.html

  You could try to squeeze by tech, and yes, GRM does let a lot get through that technically shouldn't, but that's your call. I'll throw my opinion out that if you're not legal, you're not legal. There's a lot to this event thats based on the honor system. If you squeeze things by, I feel it taints the event.

  Let me know if you have more roll bar questions. I don't know details of the SCCA stuff, but I can probably help with the NHRA pieces.

  And, let's get some details on what you're building!

  Pat

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  Aug. 11, 2010 8:08 a.m. rockthemullet New Reader

  NYG95GA wrote: Don't worry about it. Tape it down with duct tape, and explain to your tech that it's welded *under* the tape, while you hand him a fifth of Maker's Mark. Proceed.

  I like how you think!

  SVreX wrote: That is correct, but it is exactly my point. Since you won't be running 9.99, the penalty won't be much. Let's say you run an 11.2. You would be "penalized" 0.3 seconds in the overall scoring. That could easily be made up for by just finding a slightly better line in the autocross. And it will not likely mean a huge difference in your placement (is there really a big difference between being in 27th place or 22nd?) If you are not targeting the top 10, your time and money would be better spent in other areas. You'll make up more scoring in the overall by spending your time on adequate testing and tuning, or your money on a better set of tires.

  That's an excellent point. I guess to get a real grasp of its importance, I would need to understand the scoring of the event. Is everything scored directly? As in, if a car runs an 11.60 at the strip and a 49.4 in the autocross, they're score is 61.0? If that's the case, being 5 or 6 seconds off of the leader in the autocross would be detrimental to a team's placement. If a car ran 13.60 at the strip (much easier to attain than 11.60) and a 46.4 in the autocross, that team would place higher.

  Pat wrote: There are a number of differences, including tubing diameter, wall thickness, mounting plate attachment, etc. Which way you go depends on where you think the car will need the bar. For example, an SCCA spec bar isn't going to make you legal past 11.50. There's a diagram here for the NHRA specs. http://www.nhraonline.com/contacts/tech_faq.html You could try to squeeze by tech, and yes, GRM does let a lot get through that technically shouldn't, but that's your call. I'll throw my opinion out that if you're not legal, you're not legal. There's a lot to this event thats based on the honor system. If you squeeze things by, I feel it taints the event. Let me know if you have more roll bar questions. I don't know details of the SCCA stuff, but I can probably help with the NHRA pieces. And, let's get some details on what you're building!

  I fully understand that different sanctions have different requirements. In looking into both rule books, I want to see if building to satisfy requirements for both sanctioning bodies is possible, thats all. Thank you for the link, it helps a bit!

  I'm 100% on board with the honor system ideal and I would have to say that's one of my favorite parts about this event... knowing you built a car within the allotted budget, not on paper but in real life.

  Another question that has come up is: - Can parts (other than wheels and tires) be changed between events as long as both parts are included in the car's budget? I'm mainly asking about suspension components but imagine I'm talking about any part on the car.

  Oh, and what's the fun in disclosing our project before the event? Everyone will see it in 7 weeks anyway :) I may let the cat out of the bag, especially if I have a question specific enough to identify the vehicle. After all, its not like anyone else would be crazy enough to build a car in less time than we've given ourselves, haha.

  Thanks for your continued support, gentlemen.

  ~Eric

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  Aug. 11, 2010 8:29 a.m. Supercoupe Reader

  yea...like there's no other procrastinators on this board..7 weeks..that's a lifetime to some

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  Aug. 11, 2010 9:08 a.m. NYG95GA SuperDork

  rockthemullet wrote:

  NYG95GA wrote: Don't worry about it. Tape it down with duct tape, and explain to your tech that it's welded *under* the tape, while you hand him a fifth of Maker's Mark. Proceed.

  I like how you think!

  ~Eric

  You are gonna be damn suprised when you find out that is actually how much of this is run.

  I think there is actually a prize given for "Best Bribe to the Judges"

  It's all about the fun!

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