RebekahsZ Posted January 19, 2013 Share Posted January 19, 2013 Weight gain can be insidous. I went to the hardware store and bought the (8) 1" long 1/2" bolts and 1/2" nuts that I need to mount my droop limiter straps. I have a bit of a washer fettish, so I bought those too. I first grabbed grade 8 bolts, but out of curiosity, I grabbed a grade 5 bolt. I asked the hardware store attendant (we have a wonderful old-timey hardware store) to weigh one grade 8 bolt and one grade 5 bolt; the grade 8 bolt weighed 2.5X as much as the grade 5! I decided to get grade 5 since these bolts just hold nylon straps. Got home and weighed the 8 bolts that I bought with the washers and nuts: 2 pounds! If I had gotten grade 8, it might have been 4-5 pounds! I'm gonna need nitrous just to break even. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 19, 2013 Share Posted January 19, 2013 Somewhere in my build thread under the old configuration with the big wing and TRW wheels, the car scaled at 48.5front and 51.5 rear. It came in at 2709. I was expecting FAR less, with a car that is essentially a caged shell. Now the car is in the low 2600# range with the lighter wheels/tires, lighter dash, revamped minimal wiring, improved fuel delivery system, smaler batter, no passenger seat/mounts/harness, no wiper assembly, and a few carbon bits. The LS1 will get the car down into the less than 2500 pound range, which is where I would expect the car to be. Most guys get a shock when their Z gets weighed. Unless you plan out every piece of the build, you end up with a much heavier car than you planned for. Mike Quote Link to comment Share on other sites More sharing options...
johnc Posted January 19, 2013 Share Posted January 19, 2013 Focus on the ounces and the pounds will take car of themselves. Cutting off and grinding down all the unused brackets and tabs on a customer's race car saved 15 lbs. Cutting unused wires out of the wiring harness on that same car and using wire tires instead of tape to loom saved 18 lbs. Also, aluminum hard lines weigh 1/4 as much as braided AN lines. Quote Link to comment Share on other sites More sharing options...
wesmc Posted January 19, 2013 Share Posted January 19, 2013 Focus on the ounces and the pounds will take car of themselves. This is strong advice. I say almost the same thing to each customer a dozen times as we are building their cars: "Concentrate on ounces and the pounds will come." Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted January 20, 2013 Author Share Posted January 20, 2013 (edited) 1tuffz has mentioned using aluminum for exhaust tubing. Is this a pratical idea? I street my car some. When I add exhaust and a REAL rollbar, I'm gonna be break-even on performance after I add nitrous to keep the power to weight at the current level! johnc, i guess those 2" longer coil springs are gonna add a little weight too....now, if the driver could only lose 30 pounds.... Edited January 20, 2013 by RebekahsZ Quote Link to comment Share on other sites More sharing options...
wfritts911 Posted January 20, 2013 Share Posted January 20, 2013 Interesting. I never really considered the weight difference between grade 5 and 8 bolts. If my Z comes in heavier than expected when I finally get around to weighing it, I might have to go through some of my bolts and either downsize and/or downgrade them. Definitely agree with the above statements, ounces make pounds, pounds win races. Also good to know that hard lines weigh less than braided lines, guess that is motivation to break out the bender when I finally get around to redoing my fuel lines -Will Quote Link to comment Share on other sites More sharing options...
kiwi303 Posted January 20, 2013 Share Posted January 20, 2013 Interesting that they are THAT much heavier, 2.5 times the weight for the same size bolt, what are they made of? I thought the grade diff was just minor metallurgy and heat treatign changes, Much like 1040 vs 5160, Minor trace element differences, 2.5x sounds like an entirely different metal such as tin based pot metal vs iron based steel! Quote Link to comment Share on other sites More sharing options...
EF Ian Posted January 20, 2013 Share Posted January 20, 2013 You could always go all out and fit titanium bolts. Quote Link to comment Share on other sites More sharing options...
clarkspeed Posted January 20, 2013 Share Posted January 20, 2013 I actually bought some 1/4-20 aluminum bolts for interior pieces and such. Quote Link to comment Share on other sites More sharing options...
Snailed Posted January 20, 2013 Share Posted January 20, 2013 1tuffz has mentioned using aluminum for exhaust tubing. Is this a pratical idea? I street my car some. When I add exhaust and a REAL rollbar, I'm gonna be break-even on performance after I add nitrous to keep the power to weight at the current level! johnc, i guess those 2" longer coil springs are gonna add a little weight too....now, if the driver could only lose 30 pounds.... Aluminum is fine for exhaust but it needs to be built with a little more attention to detail for it to last on any type of car. Don't run it all the way to the engine, start a couple feet back. A flex joint to isolate it from engine vibration and movement is very important as are hangers that prevent swinging and are designed with large surfaces in contact with the tube to prevent cracking (straps). An aluminum muffler can be a big weight savings too. You can also look into thinner steel tubes and lightweight racing "mufflers". Burns Stainless sells some sizes of tubing in 18g/ .049" which would save quite a bit of weight. I'm hoping to have an example of a light S30 exhaust to show you in about a year and a half...sigh Quote Link to comment Share on other sites More sharing options...
SUNNY Z Posted January 20, 2013 Share Posted January 20, 2013 I've seen numerous cars use AL for downpipes (right off the terbeaux), as well as exhaust. I know a thicker gauge must be used, and also wider welds. Quote Link to comment Share on other sites More sharing options...
Snailed Posted January 20, 2013 Share Posted January 20, 2013 Yes, people do it. It's too big a compromise for a street/track car in my opinion. I would rather have a slightly heavier exhaust than risk having all exhaust gasses dumping out under the hood in the middle of a 4th gear highway pull, 50 miles from home. For a strictly drag car it might be a reasonable trade off though. Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted January 20, 2013 Author Share Posted January 20, 2013 On the grade 8 bolts vs grade 5 bolt: I took the hardware store clerk's word for that-I haven't checked it myself-the difference might not be that big. But you can feel a big difference in your hand. It just made me stop and think: I'll only spend the extra money for grade 8 in those situations where high strength is really indicated. That's all I was trying to discuss. Quote Link to comment Share on other sites More sharing options...
Leon Posted January 20, 2013 Share Posted January 20, 2013 Aluminum exhaust piping? How about Inconel: http://www.primarydesigns.co.uk/index.php/standard/exhausts Quote Link to comment Share on other sites More sharing options...
Snailed Posted January 20, 2013 Share Posted January 20, 2013 RebeccaZ, you made me curious. I'm down at the shop working on my Z and I just had to weigh some bolts (we have a huge stock of new hardware on hand). I had trouble finding many grade 5s in the exact same configuration as the 8s. Some had thicker heads or a slight taper before the threads start, etc. I couldn't find any metric bolts in different grades that matched, we don't have as many metrics unfortunately. We have lots of stainless bolts too if anyone wants weights for those... First, I weighed two 5/8" x 3.5" bolts on a digital scale. One grade 5 and one grade 8. Except for the platings and the marks on the heads, they were identical. The 5 weighed 157.7 grams and the 8 weighed 157.3 I also found two 5/16" x 1" bolts but the 8 had a taller head. The 5 was 10.7g with the thinner head and the 8 was 11.6g My conclusion is that there is no real difference that would add up to more than a gram or two on a whole vehicle Time would be better spent cutting off unused threads and swapping in slim nuts where it was safe. Changing to aluminum bolts works in some places too. Quote Link to comment Share on other sites More sharing options...
Snailed Posted January 21, 2013 Share Posted January 21, 2013 I took pictures for anyone interested. 1 Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted January 21, 2013 Author Share Posted January 21, 2013 I was wrong once before, but perhaps I was mistaken. Sorry I posted inacurate information-I did not do the bolt-to-bolt weight comparison of the bolts myself, but trusted the report of another. I only weighed the grade 5s when I got home with my loot. So glad you double-checked me, Snailed-thanks. Quote Link to comment Share on other sites More sharing options...
Snailed Posted January 21, 2013 Share Posted January 21, 2013 Hey, just trying to keep the information straight. Sharing a discovery is what this place is all about...it just didn't happen to work out. My measurements could be wrong too. I would encourage another opinion on this. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 21, 2013 Share Posted January 21, 2013 THIS... I took pictures for anyone interested. Is what makes HybridZ rock! Mike Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 31, 2013 Share Posted January 31, 2013 You could always go all out and fit titanium bolts. The Group 4 FRP Kit comes with Aluminum Bolts. Someone didn't like that, it weighed so much, so off to the Aerospace Fab Shop for a replication in CF. Since the bolts were then 1~2 mm "too long", they all got trimmed but upon cogitation...they did indeed go get Titanium. Then they spotfaced the heads with a ball mill, and gun-drilled the centers out. They also made gun-drilled Titanium Rear A-Arm Pivot Bolts... It's a disease. Quote Link to comment Share on other sites More sharing options...
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