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1.69 vs 1.80
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Picture of inferno camaro
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I've been pulling 10-12* of timing for about 2 seconds to help with consistency and stop tire shake. Car is square tube chassis car 632 conv head 2450 lbs 1.80 glide 4.86 gear 32x16 or 33x15 slick. I'm looking into a couple changes this off season. Looking at doing a high gear leave brake (for really bad tracks and to occasionally give a different look to the race) and possibly going to 1.69 planetary to calm the car down. My question is how would the 1.69 at full power compare to the 1.80 pulling 12* for 2 seconds? I've not been around many cars pulling timing and never had a 1.69 trans. Pulling 12* for 2-2.5 seconds slows the ET approx .05 to the 1/8. Just wondering if the 1.69 would work better than pulling so much timing. I've given up trying to make it quicker just want to win more rounds now. I could change back to a 4.56 but I double most races and the trans stays a little cooler with the 4.86.
Thanks
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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Pulling 12 degrees will not work Super Pro bracket racing at all on methanol. What will happen is it will print slips to the degree it does now not pulling 12 degrees. Difference being when the moisture isn't being burned off by the sun during the day, it'll pick up a bunch at night, out of nowhere.

A bunch, like a tenth.

If you have a 3, 4, 5 hundredths advantage on the tree like I did 370 pro tree racing 6.50 index it don't matter how inconsistent the car is. If you take less stripe than you win the tree by, your win light comes on 100% of the time, but 3, 4, 5 hundredths advantages on the tree don't exist in Super Pro bracket racing. You need a consistent car.

Trust me it won't be consistent at all pulling 12 degrees for 2 or 3 seconds, unless you have fuel injection with the capability to correct itself.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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If you wanna tone your can down out of the gate, put a 8" converter in it.

Pull a little timing, couple two, three, four degrees to get it going, then put it back in asap.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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Or a 1.64 low gear, it might be a little heavy for a 8". I'm not sure of power in play on your car.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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The car is I think very consistent unless it shakes in the 1st 1-1.5 seconds. A normal day the car may vary .02 in a full day. The only way it is more than that is if it quivers the tire. Best pass of the year pulling timing was 5.03 worst 5.09 (unless it shakes or spins obviously) that is from 1200 DA do 4800.

Do you think 1.69 would calm it down as much as just pulling 12*? Or maybe I would need to go 1.64. The car works pretty well pulling 12* I just don't like doing it. I pull it for 2 seconds because it shifts at 1.5-1.6 seconds and will at times spin on the shift (prep is very sketchy at times) so trying to eliminate issues at that portion of the run as well.
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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quote:
Originally posted by Mike Rietow:
Or a 1.64 low gear, it might be a little heavy for a 8". I'm not sure of power in play on your car.


1095 @ 7000 and 935 @ 5500 on Oakley dyno.
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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The simple obvious solution to soften the hit is to drop rear gear to a 4.56, 4.30 or even a 4.10 if it can pull it. Get the right converter and make it do its job. From there pull as little timing out as you have to.
Use pulling timing out only as a fine tuning tool.
Do not worry about transmission getting hot, use good fluid and it will not matter much. You can always add a better cooler if you think it needs it.
Too many people run too much timing, too much gear and that makes it hard to be fast and consistent. Now the other thing is with in reason a looser converter is usually better than one too tight.

What is your timing all in? The fact that you pull 12* timing and it only kills .05 tells me you may be running more timing than needed all in? I think there is a Sweet Spot on the timing of say 6* degrees where it really does little to nothing until you go over or under it.

Then the other thing are you sure your chassis and shocks are really working as good as possible? You may be able to pick up a little ET and some consistency with some chassis / tire tuning.

Tire shake some tires are famous for tire shake, let me guess......


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Posts: 3916 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post



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Do you have a data recorder?

Is the shake you are experiencing from too much or too little wheel speed?

IMO - controlled wheel spin is your friend.
 
Posts: 116 | Location: Richmond, VA | Registered: December 07, 2002Reply With QuoteReport This Post
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quote:
Originally posted by Rodney Pryor:
Do you have a data recorder?

Is the shake you are experiencing from too much or too little wheel speed?

IMO - controlled wheel spin is your friend.


I agree, I was working on a couple of low five second Super Pro bracket door slammers 2017 with Ohlins shocks. One in Ohio, the other in NY. Both cars responded nicely to a hump in the driveshaft graph.

Both looked fantastic leaving the gate, and repeated time slips within a handful of test runs, once near ideal clicker settings were established.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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Took the same approach on Sky down its car, Ohlins TTX 36 shocks.

He made 7 runs consecutively within a couple thousandths. He then started a thread on DRR showcasing the timeslips a couple years ago.

I established ideal clicker settings on his car in three runs down the track, through text message photos of the driveshaft graphs.

Ain't nothing to it.

Just bolted the Penske's on the MEAN GREEN dragster last night, when they're set right it'll have a hump in the driveshaft graph as well, I'm sure.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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There's all kinds of approaches for spinning the tires and running inconsistently to the 60 ft.

Trust me I know, I choose to run a 8.5" wide tire, just to keep it interesting.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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As stated, Shake can be not enough wheel speed or not enough grip, i will tell you the 1.69 will clam the leave tremendously and sometimes the car will even be quicker, we found this out with out top sportsman car. I think it will help you out as it seems you have enough power to pull the extra gear. 4 link setup and wheelie bar changes can also help, having to pull 12 degrees seems a bit much to get it to go down, sounds like there can be other changes to help get the consistency to where you want it and also possibly gain a little ET


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Posts: 2497 | Location: Gilmer, Texas | Registered: June 25, 2002Reply With QuoteReport This Post
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This is a bandaid for getting the shocks and suspension right, or sometimes simply not running enough tire pressure.


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Posts: 5727 | Location: Columbus, OH | Registered: December 15, 1999Reply With QuoteReport This Post
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^^^ what BEARD says. spend time fixing the suspension first
 
Posts: 1229 | Location: middle georgia | Registered: July 20, 2003Reply With QuoteReport This Post



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quote:
Originally posted by Michael Beard:
This is a bandaid for getting the shocks and suspension right, or sometimes simply not running enough tire pressure.

What he said
 
Posts: 13522 | Location: NJ | Registered: August 20, 2000Reply With QuoteReport This Post
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Full timing is 32*. If I could run a 16" diameter wheel I could probably get a better tire but 106" and 19" section is all I can fit. I uses to run MT's but they quit making the 2 tires I used so I've been trying other options. I have had the suspension and shocks setting pretty much everywhere. Chris Bell has helped me with suspension and shock settings. My 4 link is old so basicly have 2 settings that work pretty well. Converter goes 6450 at the hit full power, 6200 ish pulling timing.


quote:
Originally posted by Curly1:
The simple obvious solution to soften the hit is to drop rear gear to a 4.56, 4.30 or even a 4.10 if it can pull it. Get the right converter and make it do its job. From there pull as little timing out as you have to.
Use pulling timing out only as a fine tuning tool.
Do not worry about transmission getting hot, use good fluid and it will not matter much. You can always add a better cooler if you think it needs it.
Too many people run too much timing, too much gear and that makes it hard to be fast and consistent. Now the other thing is with in reason a looser converter is usually better than one too tight.

What is your timing all in? The fact that you pull 12* timing and it only kills .05 tells me you may be running more timing than needed all in? I think there is a Sweet Spot on the timing of say 6* degrees where it really does little to nothing until you go over or under it.

Then the other thing are you sure your chassis and shocks are really working as good as possible? You may be able to pick up a little ET and some consistency with some chassis / tire tuning.

Tire shake some tires are famous for tire shake, let me guess......

This message has been edited. Last edited by: inferno camaro,
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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I do have a logger, I have been on both sides of the too much too little wheel speed issue. Most of the time it shakes out past 60' so assume too much initial or not enough ass to keep it up. Killing power definitely seems to helps the issue though.

quote:
Originally posted by Rodney Pryor:
Do you have a data recorder?

Is the shake you are experiencing from too much or too little wheel speed?

IMO - controlled wheel spin is your friend.
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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My 4 link has basicly 2 useable settings (old course adjustments) 66.6" 7.9" up 71% AS. Or 58.9" 7.9" up 79% AS. I can I never have to abort a run shakes just enough to lose a little ET. I can also get 52" out 7.8 up and 90% AS but doesn't seem to like it. I have used tire pressure and wheelie bar adjustments to try and fine tune it.

quote:
Originally posted by The Bozman:
As stated, Shake can be not enough wheel speed or not enough grip, i will tell you the 1.69 will clam the leave tremendously and sometimes the car will even be quicker, we found this out with out top sportsman car. I think it will help you out as it seems you have enough power to pull the extra gear. 4 link setup and wheelie bar changes can also help, having to pull 12 degrees seems a bit much to get it to go down, sounds like there can be other changes to help get the consistency to where you want it and also possibly gain a little ET
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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I've tried pretty much every adjustment on it. I put some Kinetic 8300 penske shocks on a couple years ago that helped a bunch. Only other thing I was going to try was hanging a little weight up front but never got it done. I'm limited to 33x15x15 or 32x16x15 tire as I don't have room for tires with 16" diameter wheels which seem to be better for the issue I'm having.

quote:
Originally posted by Michael Beard:
This is a bandaid for getting the shocks and suspension right, or sometimes simply not running enough tire pressure.
 
Posts: 357 | Location: Indiana | Registered: January 20, 2020Reply With QuoteReport This Post
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If you were running national event prep, this thread wouldn't exist.

You're Super Pro bracket racing, going 4.90's 5.0's on local prep.

Slow up the front half, keep your mph.

This message has been edited. Last edited by: Mike Rietow,
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
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