Not fluent in converter stuff, but what I've seen is that spragless has it's place but maybe not in a 450-500 HP footbrake car. Slight loss of MPH and more heat build up. So, spragless more appropriate for higher HP? FTI will build me a SPRAG type in any stall I want but other companies want higher stall and more $$$. For me footbrake car with 450-500 HP and powerglide. Don't care if the car goes 7.01 or 7.15.

I don’t think you would have a problem with a sprag but saying that I went with their diode. Foot brake car running 5.70s

Any of them can break but being a small block car I don’t want to lose any MPH.

Curtis

This message has been edited. Last edited by: CURTIS REED,

quote:

Originally posted by 62Galaxie:
Not fluent in converter stuff, but what I've seen is that spragless has it's place but maybe not in a 450-500 HP footbrake car. Slight loss of MPH and more heat build up. So, spragless more appropriate for higher HP? FTI will build me a SPRAG type in any stall I want but other companies want higher stall and more $$$. For me footbrake car with 450-500 HP and powerglide. Don't care if the car goes 7.01 or 7.15.

This is my results going from a TCI 8" sprag convertor to a Hughes 9" spragless, both stall around 5,900 rpm. The motor is a 630hp pump gas 434 sbc with a glide, small radials & weighs 3050.

With the spragless, I lost around 3 mph in the 1/4 & 1.5 mph in the 1/8. ET, I gained around .07 in the 1/8th & lost about .10 in the 1/4.

I saw no noticeable increase in heat with the spragless. I like the 9" spragless for 1/8 mile, but prefer the 8" for both distances.

I would go with what FTI recommends

Maybe it’s just my combo but I lost .015 in the 1/8th with a sprag converter. Didn’t have any issues with the sprag converter but wanted to see if spragless was any better. Put my sprag converter back in and sold the other

Sbc dragster, broke a sprag and sent it back to have it fixed and converted to spragless. No 1/8' et or mph loss.

My altered was running 5.00 in the 1/8. broke converter and got a new spragless one from Hughes. Runs the same, I did not lose anything going spragless.

I understand the difference but I've only had converters witha sprag and engines with low HP.
With a spragless converter how would it effect finish line driving with lifting and getting back on it at the stripe? Does the spragless create more engine braking?

quote:

Originally posted by Eman:
I understand the difference but I've only had converters witha sprag and engines with low HP.
With a spragless converter how would it effect finish line driving with lifting and getting back on it at the stripe? Does the spragless create more engine braking?

Both of the spragless converters I’ve had each had engine braking when lifting off the throttle. My other converters would “coast” when lifting in comparison. I’ve always assumed it was due to the lack of a sprag. To the OP, the 1/8th mile shouldn’t make a difference, even with low power,with a spragless it’s typically th back half of the track you’d see mph losses but combo specific. I run 90/107mph respectively with the current spragless. That is with a stock engine running 7.5X in the 1/8th and 12.0X in the 1/4. It is certainly down mph, maybe 3 or so in a 4th gen Camaro. The previous spragless ran 147/180 and felt that was off about 2 mph down from where it should have been in a dragster.

Just some additional info to help with the decision.

After reading your responses, I'm inclined to go with a SPRAG for my moderate HP. I don't want to give up MPH and don't like the perception of increased engine braking. Seems like the SPRAGLESS is more appropriate for bigger HP where the possibility of breaking a sprag is higher. Thanks.

quote:

Originally posted by Eman:
I understand the difference but I've only had converters witha sprag and engines with low HP.
With a spragless converter how would it effect finish line driving with lifting and getting back on it at the stripe? Does the spragless create more engine braking?

From my experience, when I lift with the spragless convertor it does not pull the engine down immediately like the sprag convertor does. Same thing when lifting after a pass, the spragless drops a lot more rpm before it grabs the engine and you can feel the engine braking, the sprag convertor pulls it down instantly.

Don't do any 1/8 mile racing so I can't tell you when it does nor how it feels there.

I used to lose exactly .1 when lifting at the 1000ft mark, now it's more like .07 to .08.

I prefer the spragless simply because there is one less thing to slip/break which is why I went to that style. Did lose .1 in ET, but can live with that.

I tried a 9 inch spragless a few years back and that lasted about a month. I didn't like anything about it period

Why not use a diode instead of a sprag?

My take on the differences. I noticed that the engine drops RPM quicker when getting off the throttle at the finish line with a spragless; as mentioned above.

Trans temps did NOT change. If it did, it was barely noticeable.

No loss of MPH. No ET improvement.

ET is more predictable.

Really the only difference, performance-wise, was it's more predictable and one less part to fail-which, at least for me, means I can focus more on MY game than worrying about whether rattling the tires coming out of the box at a poor facility is going to hurt the converter or not.

In my case, I can't say whether the converter helps the car be more predictable, or if it is in fact more consistent. I noticed that after the converter change, ET stayed a little more consistent from round-to-round, and more predictable with weather changes.

1/8 mile, PG behind a little bitty 312" SBF that runs 6.80's and 90's in the heat. My other car's been spragless for eons, before it was "cool", only thing that's been done is to send it in once every so often for freshen-up. 5.80's with that one, bigger SBF, PG.

My car has data logger it did not show much if any temperature change and I could not tell any difference in engine drag on shut down. The car was consistent and no huge change there.
The main reason I choose the spragless was simply to remove a weak link in the drive line.

quote:

Originally posted by David_D.:
Why not use a diode instead of a sprag?

The only downside, is the diode is heavier, which can be a little harsh on the stator tube. Both a sprag and a diode are one way clutch's, of a different design. A one way clutch allows the stator/reactor to be active (turn) once the turbine, which is splined to the input shaft picks up enough speed, above stall. The fast spragless converters being reported in here, is a matter of the builder/manufacturer knowing the correct stator/modification to flow the oil through the stator with the least restriction above stall, yet for the reactor/stator to still maintain the capacity redirecting oil to the pump,in order to multiply torque adequately, below stall. I have a PTC with a Borg Warner sprag which is really aggressive/fast to the 1-2 shift. However I have a TSI spragless that is the quicker/faster overall, more efficient of the two. Both are excellent Opel 8" core torque converters.

This message has been edited. Last edited by: Mike Rietow,

That's another interesting point, how much harder on the stator tube is a spragless?

The least.