Change converter or keep what I have?

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Jamie V
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Change converter or keep what I have?

#1 Post by Jamie V » Wed Nov 25, 2009 7:00 pm

I need a little help from an expert on weather I should keep using the converter I have or if I should buy another one.

Here is some info.

94 Lightning Pickup 3560lbs with driver
438" small block (4.100" stroke)
C6 trans
Best 60' 1.32, averages mid to high 1.3's
Best 1/8 6.23@113mph, averages around 110-111 mph
Best 1/4 9.88@134mph, averages mid 9.90's @ 132-133 mph
4.86 gears
29.5X11.5W tires (30.6" tall)
traps 7800rpm @ 132mph, 7900 @ 134mph

Converter is a 9.5" spragless that will trans brake to 5800 rpms.

My question first is that seems to be around 9% slippage is that good/bad/or ok?
Second should I have a tighter or looser converter?
Third should I have a spragless converter?

All of these questions are more of a "is it worth the money to" type question. I don't want to spend the money if there will be really no improvement but I don't mind if there is something I'm leaving on the table. It seems to me that my MPH is low for my times. Is that true and if so is that because of the spragless converter?
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Re: Change converter or keep what I have?

#2 Post by John_Heard » Thu Nov 26, 2009 6:50 am

I would bet $ that your spragless is costing you some MPH, and very likely a little ET as well.

For your ET, it sounds like what you have is working the front half pretty good. What's the RPM drop on the shift? Do you have a MSD RPM Trace or Data logger info?

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jmarkaudio
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Re: Change converter or keep what I have?

#3 Post by jmarkaudio » Thu Nov 26, 2009 9:00 am

Read Marty's answer on spragless in the link below. I had one converted to spragless lost a tenth and 2 to 3 MPH. You might also try a tighter 8", stall around 6200 to 6500.

viewtopic.php?f=16&t=2365
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Marty Chance
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Re: Change converter or keep what I have?

#4 Post by Marty Chance » Tue Dec 01, 2009 7:18 am

John and Mark are both correct. The 1/8 mile looks pretty good , but you don't pick up much mph out the back . The stall on the converter sounds pretty close. I would keep the converter , but have it converted to a sprag type.
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Jamie V
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Re: Change converter or keep what I have?

#5 Post by Jamie V » Tue Dec 01, 2009 3:02 pm

Marty Chance wrote:John and Mark are both correct. The 1/8 mile looks pretty good , but you don't pick up much mph out the back . The stall on the converter sounds pretty close. I would keep the converter , but have it converted to a sprag type.
Marty, I saw in one of your other threads that your good diode costs about $550 is that correct? and how much would it cost to get one installed in my converter? (total cost) Last question, I can get one of your bolt together converters from a buddy of mine for around $800. Is it worth it to get that one and have you set it up similar to mine (but have the sprag in it) or just put the diode into mine? I had my motor freshened up a month or so ago and I am going to have it dyno'd this winter before it goes back int the truck (mostly to make sure the tune is spot on, but also to get a graph) would sending you that bolt together back to get setup with the dyno graph get me a better setup?

thanks again
Jamie V
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Re: Change converter or keep what I have?

#6 Post by Marty Chance » Tue Dec 01, 2009 4:57 pm

diode price $550 , we have changed the manufacturing of this sprag and have the price down to $400 now.
before you buy the used bolt together get all the stampings off of it and call me with them and i can see how close it would be for your car. If it will take major redesign work then you may not want it , but if it only needs a stator change or shimming then it is a great buy.
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358t
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Re: Change converter or keep what I have?

#7 Post by 358t » Wed Dec 02, 2009 9:37 pm

Is it possible to have a spragless converter that performs as well as its spragged counterpart?

I see so many claims of lost performance on the internet but that wasn't the case when I changed.

Scott

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jmarkaudio
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Re: Change converter or keep what I have?

#8 Post by jmarkaudio » Wed Dec 02, 2009 11:39 pm

Scott, if at any time during the run the stator wants to "unlock" and can't because it's spragless, it will cause drag in the converter. If the converter was designed so it didn't reach that point having a sprag would make no difference, but it would not slow it down either, and I would believe the converter isn't optimum as well for best ET and MPH. There is an upside to a spragless, the sprag won't slip or break cause there isn't one. The stator it self may break or slip if aluminum, mine has a CNC steel stator in it, it's very consistent and I don't expect that part of it will ever break or slip. I do plan on trying another converter with a sprag to see how mine responds sometime his next year.
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Re: Change converter or keep what I have?

#9 Post by 358t » Thu Dec 03, 2009 8:35 am

jmarkaudio wrote:Scott, if at any time during the run the stator wants to "unlock" and can't because it's spragless, it will cause drag in the converter. If the converter was designed so it didn't reach that point having a sprag would make no difference, but it would not slow it down either, and I would believe the converter isn't optimum as well for best ET and MPH. There is an upside to a spragless, the sprag won't slip or break cause there isn't one. The stator it self may break or slip if aluminum, mine has a CNC steel stator in it, it's very consistent and I don't expect that part of it will ever break or slip. I do plan on trying another converter with a sprag to see how mine responds sometime his next year.
Mark, don't you recognize my username from other sites?

Thanks for the refresher but I am aware of those details. I remember you being very closed minded on a spraggless not even having a chance of running as fast as a spragged converter. You and I's experiences are totally opposite. I firmly believe a spraggless converter will be as quick and fast in a good portion of combos as its spragged counterpart when designed correctly. At least now after our conversations you will somewhat consider that a possibility.

My post was meant to be a little sarcastic. Although if Marty or some other proffesional converter guy would like to to talk the details of what it takes to make a spragless back half as good as it spragged counterpart then I'm all ears. Or talk about what combos don't see any performance differernce between the types of converters.

Steel stators.... I think they are great if you are breaking stators but to a point I have to dissagree about them being easier on a sprag. The steel is heavier and has more mass. This puts more strain on the spragg when it has to stop it.

Scott

358t
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Re: Change converter or keep what I have?

#10 Post by 358t » Thu Dec 03, 2009 10:51 am

Jamie V wrote:I need a little help from an expert on weather I should keep using the converter I have or if I should buy another one.

Here is some info.

94 Lightning Pickup 3560lbs with driver
438" small block (4.100" stroke)
C6 trans
Best 60' 1.32, averages mid to high 1.3's
Best 1/8 6.23@113mph, averages around 110-111 mph
Best 1/4 9.88@134mph, averages mid 9.90's @ 132-133 mph
4.86 gears
29.5X11.5W tires (30.6" tall)
traps 7800rpm @ 132mph, 7900 @ 134mph

Converter is a 9.5" spragless that will trans brake to 5800 rpms.

My question first is that seems to be around 9% slippage is that good/bad/or ok?
Second should I have a tighter or looser converter?
Third should I have a spragless converter?

All of these questions are more of a "is it worth the money to" type question. I don't want to spend the money if there will be really no improvement but I don't mind if there is something I'm leaving on the table. It seems to me that my MPH is low for my times. Is that true and if so is that because of the spragless converter?
I'm not convinced that your lack of big mph in the 1/4 is the spragless converter. I've got a few questions.

-What is the rollout of the tires? I could back calculate from your 30.6" diameter figure. Just wondering what was written on them or better yet a measured rollout with the tires at operating pressure
-Are the tires Radial?
-Would you happen to also know the fallback stall after a shift?
-What are all of the details of the engine, fuel, cylinder heads, etc, etc.

Scott

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jmarkaudio
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Re: Change converter or keep what I have?

#11 Post by jmarkaudio » Thu Dec 03, 2009 12:18 pm

Yes, I think there is a place for a spragless converter, I have one in the car now. My steel stator won't break the sprag either cause there is not one in it. Since the steel stator is stationary/locked the weight has no effect other than adding to overall vehicle weight which is minimal. The converter is consistent because there is nothing to slip, and one less thing to break. And in the 1/8 mile it's not likely there will be any difference. My whole point was you can take any spragless converter and put a sprag in it, it should never be slower unless it slips or breaks, and will likely see something gained on a 1/4 mile run IF the converter reaches the point that it wants to unlock. How much would depend on the converters design, and I would think how and where the engine makes power. My old Transmission Specialties converter lost a tenth and 2-3 MPH only taking out the sprag to make it spragless with my 23˚ 427. Now our 23˚ stuff always made great low end power in low the flattened out in high, that may enhance the need for a sprag. An engine with enough power to keep the converter under a heavier load all the way down might not see that much difference, it would be farther down track before it would want to unlock. I do have plans to try the Coan I had tightened up, I also had a sprag put in it. Most likely will be after I get a better intake for it, I want to do one thing at a time to find engine improvements. Then if none of my converters match I may have to pony up for one of Marty's bolt together converters...
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Re: Change converter or keep what I have?

#12 Post by 358t » Thu Dec 03, 2009 1:36 pm

I thought it was a different brand than a TS converter that you had went back on forth between a spragless and sprag? Or maybe it was a different company that did the change back to sprag? Was the internal clearances exactly the same before and after being cut apart? What stator was in it?

Scott

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Re: Change converter or keep what I have?

#13 Post by jmarkaudio » Thu Dec 03, 2009 8:37 pm

Yes it was a TS converter, it originally had a Diode in it when new. Went to JW for a repair the first time I had an issue with the diode, and went back again to have the diode removed after losing a S/C race to Scotty Richardson because of it. :pissed: Both times it acted as if it was slipping, to my knowledge nothing else was changed and nothing else found wrong. Since then it has not been cut open, I have not used it with the SB2 as it is a PG shaft converter and my new ones I went to a Turbo spline. I still have the diode in the garage, posted pics here. Not sure if it built up debris internally to cause the issue or what happened, hasn't failed since removing it. As of this last weekend, the FTI spragless had mine running 7.62 @ 172. At some point I'll try the revamped Coan with a sprag, and see where I'm at.
Mark Whitener
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358t
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Re: Change converter or keep what I have?

#14 Post by 358t » Thu Dec 03, 2009 9:05 pm

I seen your results on another site and noticed the mph was low or worded a different way the et is very good for the mph. Do you think it is the spragless converter? What about the intake issue? That could certainly be hurting the mph.

fwiw, in good air and track conditions my spragless converter runs mid to upper 7.6x's at 173-174 in my dragster which is also sbc powered. 1/8mile mphs are in the 140.xx range so it back halves pretty good.

Scott

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Re: Change converter or keep what I have?

#15 Post by jmarkaudio » Thu Dec 03, 2009 11:13 pm

Combination of both, it ran 1.07 60ft, 4.77@ 142+ in Gainesville with my 32" tires, 1.08 and either 4.82 or 83 this last weekend in warmer Palm Beach with the 33.5 tires. Big rollout difference between the two. I have some time to work on it before the Divisionals here, the intake is the first to attack.
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