Tight converter consistency

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Archeryguy02

Archeryguy02

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I am a bit concerned about consistency with the tight converter, but I like the extra power the car has compared to the rest of the cars in my bracket at the finish line.

How much will a tight converter effect consistency? I am still working on getting the car dialed in obviously, but I want to hear from others that may have experienced a similar situation.

Car set up is below.

1968 Valiant full interior and glass minus radio. Gonna guess its around 3200 with me in it.
LA 360 stock crank and rods
Icon 741 pistons about 10.6:1
As cast Speedmaster heads, I bought the castings and had my engine builder put them together.
Oregon Cam Grinding 242/248 @ .050" .600" lift solid roller cam
performer RPM, 750 double pumper
Stock type 273 type adjustable rockers 1.5 ratio
Doug's Headers with a 17" header extension and some turn downs, no mufflers or exhaust yet.
Lock up 904 from a 1982 Cordoba with a TF2 shift kit
A PTC lock up converter that was supposed to stall at 3500 but is a bit tight at 2800 which is likely keeping this car out of the 11's at this point.
8.8" ford explorer rear end 3.73 Limited slip
Super Stock springs, slant six torsion bars, Mancini bolt on subframe connectors welded in.
26x8.5 Mickey T pro drag radial

First weekend out it ran a 12.20 @ 114.37mph
 
496 polara said:
Does it spin off the line or bog?
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It occasionally spins but I am thinking I can rectify that with some chassis tuning and better burn outs. It doesn't really bog when it hooks up it just goes but its stalling at around 2800 when everyone recommended a 3500 stall. Experienced racers are telling me it seems tight and I am told my 60' times are slow for my Et and mph at 1.900 best 60'.
 
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With a better converter you would be in the 11's (just looking at your mph)...and yes, 1.9 is slow for the ET, which is again due to the converter. Just eyeballing your combo, but I would think it would ET a lot better with a tight 8" converter (~4500 stall).

My street/race car runs a PTC 8" converter that stalls about 5200 behind my 408...works great, super consistent, and can drive around town too.
 
You have mid elevens mph.....and a high thirteens 60 ft. I would suggest getting rid of the lockup, and get a proper converter. If this is primarily a strip car, i would look for at least 4500 out of a tight eight inch. If street strip, 4000 from a tight nine.
With the mph you have, your 60 should be in the low 1.6s.
 
Archeryguy02 said:
Experienced racers are telling me it seems tight and I am told my 60' times are slow for my Et and mph at 1.900 best 60'.
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It could be the converter or it could be the tune. I would work the tune before I spent any money on a new converter.
 
Needs a converter if you think or know it's only flashing to 2800. Probably make the chassis work more efficiently as well. May find some more MPH with a good piece.

Yes, work on the tune. But, you aren't likely going to find the 3+ tenths you are missing in 60' with the current converter
 
crackedback said:
Needs a converter if you think or know it's only flashing to 2800. Probably make the chassis work more efficiently as well. May find some more MPH with a good piece.

Yes, work on the tune. But, you aren't likely going to find the 3+ tenths you are missing in 60' with the current converter
Click to expand...

One night at the drags I saw a valiant with less cubes/cam/carb/tyre and less gear weighing more than mine with a 2500 converter run better 60fts than me. Was a real eye opener to say the least.

The real give away was when he told me who built the carb for him, then I knew why the car was really quick especially in the 60. Torque determines where your converter stalls and the tune affects the torque you're motor produces.
 
Hysteric said:
One night at the drags I saw a valiant with less cubes/cam/carb/tyre and less gear weighing more than mine with a 2500 converter run better 60fts than me. Was a real eye opener to say the least.

The real give away was when he told me who built the carb for him, then I knew why the car was really quick especially in the 60. Torque determines where your converter stalls and the tune affects the torque you're motor produces.
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OK so what should I focus on tuning first? Chassis? Carb? Timing? I ordered some new shocks to help with weight transfer that arrived at the house today. Should I raise or lower the torsion bars to help weight transfer?
 
crackedback said:
Needs a converter if you think or know it's only flashing to 2800. Probably make the chassis work more efficiently as well. May find some more MPH with a good piece.

Yes, work on the tune. But, you aren't likely going to find the 3+ tenths you are missing in 60' with the current converter
Click to expand...

I really appreciate all the help guys.

I know my converter is tight, is it possible to tune enough power out of it to raise the flash point several hundred RPM? The motor is not falling on its face.

I am not real interested in going much faster than I am right now because I want to run a 12.0 and slower bracket. I want to know how much more inconsistent will the tight converter be compared to the correct converter?
 
Archeryguy02 said:
I really appreciate all the help guys.

I know my converter is tight, is it possible to tune enough power out of it to raise the flash point several hundred RPM? The motor is not falling on its face.

I am not real interested in going much faster than I am right now because I want to run a 12.0 and slower bracket. I want to know how much more inconsistent will the tight converter be compared to the correct converter?
Click to expand...
You may want to try taking some timing out of the engine and swap out the torsion bars for a set of /6 bars so the car transfers the weight to the rear of the car faster. An adjustable set of drag shocks in the rear would not hurt.
 
33IMP said:
You have mid elevens mph.....and a high thirteens 60 ft. I would suggest getting rid of the lockup, and get a proper converter. If this is primarily a strip car, i would look for at least 4500 out of a tight eight inch. If street strip, 4000 from a tight nine.
With the mph you have, your 60 should be in the low 1.6s.
Click to expand...
I was going to get rid of the lock up but the shop I got my converter through recommended leaving it in there, it only works in high gear and is great for cruising around. The downside of the lock up is its hard to get them to stall very high, I was told this would stall a fair bit higher than it is. It wouldn't be too much work to 86 the lock up and get a non lock up converter. I make the car much faster I will just have to detune it to stay in my bracket, and I like the extra mph at the top end for wheel racing. I just want to know how much the tight converter will handicap my consistency.
 
512Stroker said:
You may want to try taking some timing out of the engine and swap out the torsion bars for a set of /6 bars so the car transfers the weight to the rear of the car faster. An adjustable set of drag shocks in the rear would not hurt.
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I have /6 bars, and there is a summit box with some drag shocks waiting at the house. Less timing will make the car leave better?
 
Archeryguy02 said:
I have /6 bars, and there is a summit box with some drag shocks waiting at the house. Less timing will make the car leave better?
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You posted that you wanted to "tune out power"
The easiest way to take power out is to take timing out of the engine.
Like reduce the total timing from 36* to 32*
 
Archeryguy02 said:
I was going to get rid of the lock up but the shop I got my converter through recommended leaving it in there, it only works in high gear and is great for cruising around. The downside of the lock up is its hard to get them to stall very high, I was told this would stall a fair bit higher than it is. It wouldn't be too much work to 86 the lock up and get a non lock up converter. I make the car much faster I will just have to detune it to stay in my bracket, and I like the extra mph at the top end for wheel racing. I just want to know how much the tight converter will handicap my consistency.
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Who built the converter?
 
Everyone is giving you good advice , it's a tight converter-for the street...so figure out where you want to be most of the time and decide from there.
Loose converter on the street sucks.
 
Archeryguy02 said:
OK so what should I focus on tuning first? Chassis? Carb? Timing? I ordered some new shocks to help with weight transfer that arrived at the house today. Should I raise or lower the torsion bars to help weight transfer?
Click to expand...

Start with the carb and timing curve because they are linked together. You already have the hardware to run 11's so why not see what you can squeeze out of it before you throw money at it. What do the plugs look like?
 
Archeryguy02 said:
I really appreciate all the help guys.

I know my converter is tight, is it possible to tune enough power out of it to raise the flash point several hundred RPM? The motor is not falling on its face.

I am not real interested in going much faster than I am right now because I want to run a 12.0 and slower bracket. I want to know how much more inconsistent will the tight converter be compared to the correct converter?
Click to expand...
Are you leaving the line from idle or holding the rpm ‘s up higher and then launching? I have a TA 3500 tight and it gives better launches and 60’ times leaving from idle (1000-1100) every time. At first I tried different rpm’s but determined off idle worked most consistently and yields the 3500 flash stall
 
Archeryguy02 said:
.................. I just want to know how much the tight converter will handicap my consistency.
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I don't think a tight converter will effect consistency...my old nitrous setup had a tight converter, and when I ran it NA it was a bit of a dog...but it was a consistent dog. I think the issue you are seeing has more to do with the lockup converter. I have never used a lockup in a racing application, but it sounds like a really easy way for the car to be inconsistent (depending on when lockup happens and such).
 
By the way, if you want to run 12.0 with a high 10 second car (which is pretty much what you have) let me know (I have a bunch of tips for slowing cars down)...I did that once, just for a season....made the division finals team, runnered up in the shootout race at the finals...pretty good year...but hurt the trans in my car (long story).
 
512Stroker said:
You posted that you wanted to "tune out power"
The easiest way to take power out is to take timing out of the engine.
Like reduce the total timing from 36* to 32*
Click to expand...
No, I am running a 12.0 bracket so making the car run 11's at this point is not my goal. If the car ran faster I would have to detune to stay in my bracket. There are lots of cars that are detuned to run 12.0 in this class. The way the car is now I have more power than they do on the top end for wheel racing them when I catch them. I am was simply trying to find through others experiences how much a tight converter will hurt consistency.
 
Hysteric said:
Start with the carb and timing curve because they are linked together. You already have the hardware to run 11's so why not see what you can squeeze out of it before you throw money at it. What do the plugs look like?
Click to expand...
Almost white, just a bit dingy.
 
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