suspension and ignition setup need help
I run my 66 chevelle in a club racing event called supercar shootout. Stock tires, stock intake, stock exhaust manifolds. I'm running an msd digital 7 box with a stock eliminator style big block. Best run 11.22 @ 122mph. I know there's more in it and I'm looking for someone with the knowledge and talent to help me. I'm willing to meet at etown atco or cecil county and compensate anyone willing to help me pick the car up.
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Re: suspension and ignition setup need help
Any suspension modifications allowed? I'm sure your 60' times could be improved upon. What type of rear tire are you calling "stock"?
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Re: suspension and ignition setup need help
http://www.supercarraces.com/SC2014-13.jpg G70-14 redline. Best 60 ft 1.74. I'm pulling out 15 degrees of timing for 1.5 seconds leaving off the foot brake. I know the digital 7 is capable of much more than I'm using it for now. I have santhuff springs up front with del alum bushings and single adj. QA1s. In the rear UMI adj. uppers, boxed lowers stock springs and sway bar and double adj QA1s. I'm losing ground to some of the other racers who have figured out how to get high 1.5 to 1.6 60 fts.
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Re: suspension and ignition setup need help
There are a lot of folks on here that could help you, but I think they would all need quite a bit of info about your combo. 11.22 is pretty stout on redlines, and is at or below the index for your 66 with any engine except the aluminum head 396/375hp at 11.20.
Rick Thomason GTOMayhem |
Re: suspension and ignition setup need help
The class is run heads up with a sportsman ladder. .400 pro tree. My combo is a "stock appearing" 360hp automatic with a turbo 400 and 4.56s. The motor made 660 on the engine dyno running through the stock exhaust manifolds, correct oval port heads, and cast iron intake which uses a holley. The car weighs 3845 with me in it. The dominant cars are hemi mopars and L89 69 camaros and novas. I feel the front of the car works well but the rear is where I could use the expertise of someone else. As well as getting full use of the MSD.
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Re: suspension and ignition setup need help
What do they allow on the rear suspension?
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Re: suspension and ignition setup need help
your performance is commendable giving the information posted.
If you can get to the point where it will leave without retarding time, that will be a big part of reaching your goal. Have you tested with fixed timing? If not, try and see what happens. |
Re: suspension and ignition setup need help
Agreed - Without a tire swap the only other thing I can think of as far as suspension are no-hop brackets...https://www.summitracing.com/parts/qa1-5213/overview/
These were used on my partner's '66 with success for a 1.51 60'...he had less hp and was closer to 4000 pounds, but did use slicks for those runs. Unsure with those tires what the outcome of a higher stall converter would net. http://i434.photobucket.com/albums/q...ManCave006.jpg Is this you at the 2:19 minute mark? https://www.youtube.com/watch?v=1ltE...ature=youtu.be |
Re: suspension and ignition setup need help
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Re: suspension and ignition setup need help
No hop bars are allowed. not much else. Trying to leave with full bore timing blows to tire away.Adding weight ballast in the trunk has been suggested but putting an extra 200 lbs in the trunk and dragging it down the track is a tough pill to swallow.I know the digital msd is capable of ramping in timing in different ways I'm just not sure of all the things its capable of. Rear shock settings are another area where I know someone with more knowledge could be helpful.
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Re: suspension and ignition setup need help
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According to those rules, his upper arms are not legal. 13.01 Traction devices are limited to hop stop bars for upper control arms on coil spring cars. 13.02 Upper and lower control arms on coil spring cars must be correct. From his OP: In the rear UMI adj. uppers, boxed lowers stock springs and sway bar and double adj QA1s. So, evidently, the rules have changed. |
Re: suspension and ignition setup need help
I'll bite..a little bit...L-O-L:
If you're taking timing out to hook it, I'd try the following and I'd put the timing back in: More sophisticated shocks...I suspect what you have now isn't exactly the best for the job. One of these if you can get away with it: H&R Parts & Stuff rear "sway bar" (more of an ARB than a sway bar since it does not attach to the lower rear trailing arms). Link: http://hrpartsandstuff.com Hope this helps. Wayne |
Re: suspension and ignition setup need help
The no hop bars may allow you to get better geometry than the adjustable bars by themselves. (the rules seem to say adjustable upper arms are not legal, if they are, I wonder what else that appears to not be legal actually is?)
Have you tried changing spring rates on either end of the car? The timing curve adjustments on the MSD to allow you to launch with low timing and bring more in will simply be a matter of testing. There may be someone who can give you a better starting point than you have, but the only way to get it dialed in is to go rent the track and beat on it, to see how much timing can be brought in and how soon. |
Re: suspension and ignition setup need help
Leaving at idle or stalled? Not hitting the tires hard uncertain if adjustable shocks are any benefit. Do they allow deep stage at these events?
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Re: suspension and ignition setup need help
to me, the largest handicap to overcome is the tire. ANYTHING that you can do for a "sticky" tire will be a huge help.
Experimenting with the above mentioned suggestions AND a better tire holds potential to greatly increase performance. |
Re: suspension and ignition setup need help
and speaking of weight, ANY weight removed from driver forward is good. If you remove 10 pounds from the front, add it back to the rear.
A "ballasted" trunk lid is good. [meaning adding weight high and rearward] |
Re: suspension and ignition setup need help
It sounds like you are running an automatic..
In this case, the rules (as posted here), leave a lot of room for experimentation. What do the fast guys use? 400?, 2.20 low gear?, 350? ..Aluminum drums (I'll bet they do..How about a Powerglide? Converter rule is wide open..Again, what do the fast guys use? |
Re: suspension and ignition setup need help
Yes. That was last summer at englishtown. Much appreciation for all the responses so far.
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Re: suspension and ignition setup need help
Wow. lots of feedback here. Front springs are Santhuff 250lb. rear springs are stock. Front shocks are QA1 single adj. Rears are QA! double adj. Adjustable upper arms are technically not within the rules but are not enough of an infraction that anyone complains. 6 inch rims are all that's allowed but most racers run 7s. The basic premise of the class is that the cars appear stock to the casual observer. I'm running a turbo 400 with a 2.10 first gear with all light weight internals as well as a 12 bolt with 4.56s with a spool and gun drilled axles.
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Re: suspension and ignition setup need help
I leave off the foot brake at 2000 rpm pulling out 15 degrees of timing for 1.5 seconds.
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Re: suspension and ignition setup need help
It sounds like you are pretty much maxed out given the restrictions. I agree with Alan about testing the limits of launching be it thru timing events or other means. The testing never ceases for any of us...
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Re: suspension and ignition setup need help
Another engine builder, who is a friend of mine, and responsible for some historic performance, told me "it isn't so much that we know what makes the car go fast, it's that we know so much about what doesn't make it go fast, or even makes it go slower". All of that comes from testing, relentless, exhaustive, tedious testing. Unfortunately, there is no known substitute.
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Re: suspension and ignition setup need help
Sneeky pete
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Re: suspension and ignition setup need help
Four wheel scales? 50/50 or better? Just some things to think about.
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Re: suspension and ignition setup need help
After giving this some thought I maybe would be inclined to look to the other end of the track instead of beating a dead horse....err, tire I mean. :p
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Re: suspension and ignition setup need help
Do they check your tires other than size? Some companies sell products to rejuvenate your tires. Think about that and let it "soak" in.
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Re: suspension and ignition setup need help
Can you retard the cam any? If so try that and bring the timing in more aggressive. Larger "worked on" intake, delay the secondary slightly on the carb. Also, I would try a 7" rim. By the picture the tire looks like it is starting to run over itself like it is to low on air. But, I know you do that to try and hook. The other way would be to put a 4.30 gear in it and let that hook and then try to be more aggressive with the timing and use more torque through the trans low gear setting. Also, do you have a soft hitting converter? By the way that is FLYING! for anything much less a very stock appearing car. Like everyone said testing, testing, testing. Keep up the good work.
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Re: suspension and ignition setup need help
I raced one of these cars about 20+ years ago. It was a 331 small block, TH400 and 5.13 combination.
If you take a side view of your car and draw the imaginary lines through the rear control arms you will find the instant center of the car probably about 6-8 feet in front of you, maybe more. The IC needs to be about where the engine block/trans come together or at worse the front of the engine. According to the rules, you might be able to do the following. The UMI adjustable upper links really don't do much more than adjust the pinion angle, kind of like the upper link in a ladder bar car. So, if you can find another upper control arm - you only need one, cut it in half, mount the half to the rear and then have your stock arm mounted in front to the frame and bring it down on top of the half. Tack weld it there, do the other side and then pull them out to weld them up. Put these in and you just moved the IC where you need it with "stock" parts. I think you will be very pleased with the 60' after this modification. |
Re: suspension and ignition setup need help
We downloaded this MicroSoft Excel file which was a big help in understanding, and getting the rear edge geometry set up in our 81 Malibu. All instructions are in the file. Measure the end point locations of all rear control arms and enter them in the spreadsheet. It will then calculate and graphically depict the Instant Center location and several other critical dimensions. You can then alter the numbers to see what you need to change to arrive at the Instant Center you desire. Good luck.
www.patooyee.com/calculators/4BarLinkV3.0c.xls |
Re: suspension and ignition setup need help
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The 2.10 1st gear is hurting not helping and who built the trans? What exactly is your performance goal? |
Re: suspension and ignition setup need help
Many of the F.A.S.T. racers use ludicrous amounts of ballast in the rear to hook on those tires.
Beautifull car !!! |
Re: suspension and ignition setup need help
i'd let those tires soak in a tube of vht the night before a race to try and soften them or make them more sticky in anyway possible
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