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AmickRacing
06-23-2012, 06:32 PM
2005 rocket, WISSOTA rules, D-55 tires.
Springs LF-450, RF=400/600 dual rate, 1.25" gap. LR-200, RR-225. 5th-afco progressive with 0-.25" preload
Shocks - integra, set for dryslick
Rear bars LRT-top, RRT-Middle, LRB 2nd up (using 2" shorter arm and plate), RRB 2nd up.
Panhard bar is 8.75" up on the frame, pinion is bottom of slider, approx 1" below driveshaft.
left side is 54.5, rear 54-56 depending on fuel, usually run around 70-80# bite in the LR, for the race last night put 6 turns in the LR and it was better.

I have the RR shock on the inside mount, also have a 2" drop mount on the top (lowered the spring table).

1st part of the year I struggled getting the car free'd up when there was tack. The last few weeks the track has been very dry and slick. There are some ruts and rough spots through the corners but it's getting better. Overall the car seems to work pretty good, it has decent drive off of the corner, doesn't seem to be too loose or tight going in and through the middle. Just can't seem to get the car onto the RF often or consistently, and it kind of feels like there should be a bit more side bite in the rear of the car also.

I generally drive the car straight, I like being able to roll into the corner and pick up the throttle as soon as I can vs the guys who barrel into the corner sideways.

I think I might need to open the gap on the RF dual rate stop up a bit, let it get a bit more of soft spring lean before it hits the stiffer spring. Keeping a bit more LR bite in the car should cancel out the drive issues of increasing the gap on the RF hopefully.

I've been center or just above the driveshaft with the panhard bar when it's tacky and that does help, just doesn't seem like lowering it does as much. I haven't raised it on the frame yet. I've toyed with the idea of a shorter j-bar (current is 21") or possibly a straight bar, but with the ruts I think that could upset the car too much.

Any other ideas off the top of your heads to look into and try?

FlatTire
06-25-2012, 10:13 AM
Raise the jbar on the frame and drop it on the pinion for starters.

Also, you can take a few rounds out of the RF and RR along with adding rounds to the LR when you get on the slick.

dualdj1
06-25-2012, 10:37 AM
straight bar would be risky with rough track. it's faster acting, so helps having a little more rebound in LR to smooth it out a little. advantage to straight bar is that it helps with body roll the lower you go with it, and also adds forward drive. it *can* help with side bite, but you have to tune for it, and it's quite a bit different setup than with j-bar.

Matt49
06-25-2012, 03:58 PM
Where is your ballast located?
If I'm understanding you right, the problems you are describing are car not getting over on the RF and not enough side bite.
Start raising the ballast in your car and I bet both of those problems go away.
You are already pretty extreme on j-bar angle/rake so I wouldn't go there for more side bite.
Like dual said, with the short straight bar, you could have your hands full in a real big hurry on a rough track. You'll feel like there's a pogo stick under your car.
I would say your weight just isn't transferring enough as a whole. Raising it up will really help. How much to raise it depend on where it is laterally and how big the ballast pieces are.
Where is your ballast now and how big are the pieces?

AmickRacing
06-26-2012, 02:24 AM
Unfortunately I don't have any ballast mounted on the car. I guess that's a good thing since the car scales out pretty close to the numbers in the book, just sucks because you can't move anything around.

My battery is above the LR axle, I have pondered moving it towards the center of the car or a bit to the right to help get the left side weight down some. It won't be super easy to do, but wouldn't be the end of the world either.

My fuel cell has no adjustments to raise it, but I'm betting I could fix that problem in a couple hours.

My engine is mounted I believe in the 2nd hole up on the motor plate, might be 3rd, I honestly don't know. I know it's a huge chunk of weight, but I kind of struggle to believe that raising it less than .5" would be a big difference. Also I should have mentioned I do have the motor set back 3.375" back (almost 10" setback). It's a steel headed, steel block motor fwiw.

My car is already overweight, I do believe the driver is somewhat to blame for that lol. I have to weigh 2300, and right now I'm around 2400 give or take depending on fuel (try to scale with 13-15 gal). Speaking of fuel, the last couple races I've added more fuel than I ever have with this car to get the rear % up a bit, but I'm kind of thinking that might be part of the mistake to. Taking too much weight off of the front tires...

I did play around with some lead before the season, if I add 35 lbs to the right side frame rail (about camshaft height) I can reduce the left % by .5.

After doing more thinking, I'm starting to think I should possibly throw that lead on, and reduce the fuel load some (was going out with around 25 gal for a main). I for some reason have it stuck in my head that the car should produce enough forward bite with the bars etc, that I wouldn't need quite so much fuel. Plus, if I can get it rolling through the corner better (faster) I won't need so much rear also.

I did end up lowering the front camber to roughly 4 deg on each side from the 5.5 rocket recommends. This really helped the RF tire get heat all the way across it. Last week I lowered the RF upper A-arm to the bottom hole in the frame, and it seemed to take 2-3" of working tire away (outside edge was cold).
Not sure if I should drop it down, and take a bit of camber out of the car, or possibly it'll just roll over harder on the RF with the other changes, and I'll be ok. Tough call for sure!

Thanks for the help so far fella's!

lovinlatemodels
06-26-2012, 08:37 AM
I would get your fuel cell up to help your weight transfer first then work on moving weight your battery would be the first thing i move before adding lead. And i wouldn't get too concern with weight of your car yet i think a heavier well balenced car is much better then a lighter unbalanced car i was always 50 to 70 lbs heavier.

joedoozer
06-26-2012, 09:20 AM
Get that cell up in the air, it makes a huge difference. My old cell (black one) was a 32 gallon. I never ran more than 15 gallons in it. The new cell is a 16 gallon. I moved that weight over 1 foot straight up. And it made a big difference in how the car rolled over.

dualdj1
06-26-2012, 09:57 AM
Ballast = any movable mass, including your battery/fuel cell. As Joe and lovin said, the higher up you get it, the more transfer you get. Same goes with your engine. You may not think half an inch makes much difference, but when you're talking about that much weight (steel heads), it will make more than you think. if you aren't rolling over well, and have room to go up with it, move the engine up too.

Now, the other thing to keep in mind (battery is a good example), when you move weight to the right, you are changing your static weight, and you won't actually transfer as much weight (it'll already be over there). That's not necessarily a bad thing, it just changes the dynamic effects. Higher left % can help with forward bite. what you need is for that % to be able to decrease easily when rolling through the corner (ie transfer right).

The other thing to remember when talking about weight transfer, is your roll center. in simple terms, the farther weight is from the roll center, the easier it will transfer. Balance that with what you want your starting, static %'s to be.

Rear roll center, is halfway between the upper shock mounts side to side, and height is halfway between the mounting points of your panhard bar.

So another thing you can do to get more transfer is move your LR spring from angled in, to straight up, or if your RR was straight up, angle it in. This changes other things though such as spring rate, etc, and may not be possible or practical on your chassis.

hpmaster
06-27-2012, 06:00 PM
Get that cell up in the air, it makes a huge difference. My old cell (black one) was a 32 gallon. I never ran more than 15 gallons in it. The new cell is a 16 gallon. I moved that weight over 1 foot straight up. And it made a big difference in how the car rolled over.

Car looks good now hows it drive?

AmickRacing
06-28-2012, 12:45 AM
I almost hate to make this post, but lesson learned...
Threw the car on the scales tonight to double check where I was at. I added 10 turns to the LR last week, and it weighed out with 70# LR bite with out me in it. Seemed awfully low, so I took the 10 turns out, and I was at 5# RR bite. There's problem #1.

Problem #2, I have no idea what happened, or how it happened, but the stop nut for the dual rate RF was 3/8-1/2" gap... problem #2.

I did lower the J-bar on the pinion, and knowingly didn't check the side to side of the QC. It was just over 17 instead of the 16.5". Don't think that was a huge issue, but coupled with the other 2, wasn't helping.

Changed things back to the baseline, where it was supposed to be, and made a few suggested changes from this post... we'll see how things go friday! I'm pretty confident it'll be much better!

joedoozer
06-28-2012, 05:43 AM
I almost hate to make this post, but lesson learned...
Threw the car on the scales tonight to double check where I was at. I added 10 turns to the LR last week, and it weighed out with 70# LR bite with out me in it. Seemed awfully low, so I took the 10 turns out, and I was at 5# RR bite. There's problem #1.

Problem #2, I have no idea what happened, or how it happened, but the stop nut for the dual rate RF was 3/8-1/2" gap... problem #2.

I did lower the J-bar on the pinion, and knowingly didn't check the side to side of the QC. It was just over 17 instead of the 16.5". Don't think that was a huge issue, but coupled with the other 2, wasn't helping.

Changed things back to the baseline, where it was supposed to be, and made a few suggested changes from this post... we'll see how things go friday! I'm pretty confident it'll be much better!
Amick every time I brainstormed in the garage and went to the track with a "can't miss" set up, it was out in left field lol. But you found some things wrong, so it's a step in the right direction.


Car looks good now hows it drive?
It did tighten the car up, but it got me the action I needed, so I tuned accordingly.

dualdj1
06-28-2012, 10:34 AM
I did lower the J-bar on the pinion, and knowingly didn't check the side to side of the QC. It was just over 17 instead of the 16.5". Don't think that was a huge issue, but coupled with the other 2, wasn't helping.

It makes more difference than you think. When your axle is moved side to side, it changes spring/shock angles, and in turn spring effectiveness, ride heights, weight to the tires, etc. even a half inch can make a difference.