Since we are hoping to go faster than 13.49 and are cutting the roof off to make a convertible we will need a 5 point roll bar per NHRA specs. We are planning on making an 8 point roll bar just for our own piece of mind. This will be make from 1 3/4" .120 erw tubing, I am assuming that since I am buying this tubing fresh it will go in the budget at my cost. That looks like about $3.29 per foot x however many feet of tubing end up in the car.
My question is we are planning on adding some other structure to the car, dash hoop, front down bars, additional bar across top of door, and maybe a few others. My assumption is that if I make this out of material I buy out of the drop box or come out of my own "scrap" heap, then this can go on the budget at current scrap pricing. My supplier that is 50 cents per pound. This will probably be a mixture of tubing sizes, I have some 1 1/2" and some 1" tubing as well as some 2 x 2 and may get some more depending on what is available next time I visit.
Mostly I just want to make sure I am thinking about this correctly before we proceed.
Tom Suddard
Director of Marketing & Digital Assets
2/12/20 4:12 p.m.
Yes, that all sounds correct.
Stampie
UltimaDork
2/12/20 4:37 p.m.
I believe 13.49 will make you the fastest Q45 on Challenge history. I believe Mr. Neuman holds the record at 13.9.
Stampie said:
..... I believe Mr. Neuman holds the record at 13.9.
Was that bottle fed or "all motor"?
Or just don't cut the roof off?
Stampie
UltimaDork
2/12/20 6:33 p.m.
Indy-Guy said:
Stampie said:
..... I believe Mr. Neuman holds the record at 13.9.
Was that bottle fed or "all motor"?
That was mucho bottle and pretty sure that run did in his trans.
In reply to poopshovel again :
Not a chance, goal is to get weight down to 2700 lbs. besides our theme we need to get rid of the roof
In reply to Stampie :
Here is a very optimistic guess, but I think 13.49 might be in reach.
In reply to Stampie :
2 second shifts really slow you down. I should really buy another one.
I'll believe a sub 13.5 Q45 when I see it.
SVreX
MegaDork
2/12/20 8:08 p.m.
In reply to Fladiver64 :
If the goal is purely weight reduction, doesn’t the roll bar weigh more than the roof?
In reply to SVreX :
Truthfully it is probably about a wash, but I think we are cutting so much out of the car that we need to add some stiffness back anyway. We are losing the roof, trunk, most of the deck lid, about top third of the doors, firewall, front fenders, hood . There is a lot of steel that will be removed, replaced with pipe and fiberglass panels. Part of this is just the fun of building something different, I challenged the guys to think outside the box and get a bit radical. We may not make the goal and we may blow it up at the challenge but we are going to have a good time doing it.
Since we are allowing teens to drive, we thought he roll bar is a good idea, it also make nervous moms happy.
That same calculator told me Datsaniti would run high 11's/low 12's, instead I went 12.9 (2500 lbs, 250 + 100 shot, and not much spin). There is a lot more to it than just power:weight.
Robbie
MegaDork
2/13/20 10:31 a.m.
A more accurate way to use those calculators is to look up the car and driver or road and track tested 1/4mi time from when the car was new.
Plug that time and the stock weight into the calculator to get the "real" hp. Then use that hp number with your updated weight.
Stampie
UltimaDork
2/13/20 11:34 a.m.
In reply to Robbie :
That's assuming factory drivetrain. In this case the diff has been swapped from a 2.74 open diff to a 3.57 LSD.
In reply to maschinenbau :
I agree, I did say that was a very optimistic guess. Even if we just got to 13.9 I would feel better having a roll bar in place.
In reply to Robbie :
Robbie using your method the hp number comes in at 225, so at 2900 lbs that gives us 13.65 and if by some miricle we get down to 2800 we hit the magical 13.49.
The bottom line is we will be installing a roll bar since I will have other people teens driving the car, and as team leader I think it is worth the weight and budget costs for added piece of mind.
In reply to Stampie :
What did you have the wieght down to when you ran it last?
In reply to Fladiver64 :
Definitely feels good to have the roll bar, even just in the 13's with a roof.
Stampie
UltimaDork
2/13/20 5:37 p.m.
In reply to Fladiver64 :
I'll have to confirm but IIRC ~3200 lbs and 14.4.
Stampie
UltimaDork
2/13/20 5:59 p.m.
Found a post where I said we were 3158 without driver. I was 199lbs on the 14.4 run that year.
In reply to Stampie :
The 14.4 with a 3300 lb weight comes in right at 225 HP on the estimator. About the same as the 15.1 at 3800, should be interesting to see where we end up.
All this drag talk just makes me wish it was october already. Cant wait to see you all again and see what everyone brings.
Much excite.
surfshibby07 said:
All this drag talk just makes me wish it was october already. Cant wait to see you all again and see what everyone brings.
Much excite.
Doesn't have to be October to go racing. I need to remind myself of that this year.
In reply to Patrick :
Very true. I have a few events im going to this year but this event is just so fun and you dont know what to expect. The other events i know the other cars im against are just as fast if not faster than me lol
