Javelin for NASA American Iron

[Bryce]

I was thinking about your vibration....

Do you have a lot of body lift at high speed? If so you may have a pinion angle change that is leading to vibration. It would be interesting if you get the same vibration on a chassis dyno.

[asifnyc]

hey Bryce,

I did think about a chassis dyno and am looking into that. my pan hard bar is ABOVE my axle and people have commented that it is not ideal and could/would cause lift.

here's a pic of the car leaning... looks like a lot to me but what do I know?

http://www.gotbluemilk.com/web120212...s/image42.html

[Track Junky]

I'd drop the panhard for sure. Try that before making any other changes. One change at a time so that you know what and why.

[Flash68]

Congrats on a successful first race! Car looks bitchin!

[68protouring454]

nice job.
Ideally you want the rear roll center as low as possible, however that generally goes with higher spring rates to keep the car balanced.
How long is your phb? center to center? The center of it is the rc of the rear of the car, so you want to get the phb as long as possible to put the rc in the middle of the car,so that the forces on the springs and shocks are even side to side. Thats why watts links are so good for road racing in a stick axle application.
I would never go higher then axle centerline for the phb height, however you will need to stiffen the springs/shocks as you lower the phb or you will just create more of a push.

[DTM Racing]

Very cool write up. I'm tossing the Idea around for an AI car next year as well. Your story has given me a bit of inspiration.

As to your vibration, I had a similar issue, and it ended up being the rear end was junk. Swapped to a new Speedway Engineering unit, new Currie third member, and no more high speed vibes. I know that is probably no what you want to hear, but at a minimum I'd check the rear axle for "trueness" and pic yourself up a second carrier to rebuild. Never hurts to have a spare set of gears around.

[asifnyc]

well, race weekend number 2 is this weekend... here's the schedule in case anyone wants to come out. This is at Infineon (Sonoma, CA) again.

Sat
8:05am warmup (20 mins)
10:25am qual (20 mins)
2:10pm race (30 mins)


Sun
2pm warmup (20 mins)
3:25pm qual (20 mins)
5:20pm race (30 mins)

and here's a write up of some recent activity... http://asifnyc.com/?p=1284

ended up building a new, aluminum driveshaft. hoping that's addressed the vibration. we'll see...

[Track Junky]

Good luck Asif, I'm going to try and get out there again and lend a hand if you need it

[asifnyc]

cool, hope to see you. you bringing the white camaro again?

[Track Junky]

I dropped the white Camaro off at Vinces new shop last weekend. Too lazy to throw the heater box in so I asked Vince to do it for me. Talked to Sevilla today and it sounds like he's bringing his '67 Camaro so it looks like you will have two extra hands.