Converter. My Select/Coan 258 slips around 1.5%. Here's another Select/Coan going into overdrive.

The overdirve is actually pretty common in Top Sportsman cars.

quote:

Originally posted by Coloradoracer:

quote:

Originally posted by Big Steve:
I agree, looks like its a little tight down low and loose on top, opposite of what he needs

What are you looking at that tells you that? Trying to learn how to read the graph correctly so I can apply that to my stuff.

We covered this in the gears thread. The 6000 stall (arrow on left) tells us the converter is tight. The 7900 rpm at the stripe tells us according to the 34" tire, 4.10 gear at 154mph, the converter is inefficient slipping 20% plus.

The ultimate super charger converter is loose (high stall) for boost however efficient for mph (rpm). That's that obsolete Australian Cortina core 9" converter I posted a pic of.

The latest trick of the week is put in a very tight stator and install a dump valve with a restrictor controlled by a timer. Knock out a bunch of converter pressure down to low raise the stall and get the car moving and bring it back in to lock up the converter down track. The theory is good IMO, but it creates another variable in the tune up and will require some testing to find the sweet spot. You can kind of look at it like a timing curve for your converter I guess

^^^^^ http://www.rosslertrans.com/on...05/category=40293040

quote:

Originally posted by Big Steve:
The latest trick of the week is put in a very tight stator and install a dump valve with a restrictor controlled by a timer. Knock out a bunch of converter pressure down to low raise the stall and get the car moving and bring it back in to lock up the converter down track. The theory is good IMO, but it creates another variable in the tune up and will require some testing to find the sweet spot. You can kind of look at it like a timing curve for your converter I guess

That'll work great if you have a needle bearing thrust on the engine to open the option of raising the converter pressure above 125 psi, where it is safe to run with a conventional thrust in play currently on the engine, presumably speaking. You're not gonna be able to affect the converter to the extend you wanna otherwise. You get a needle bearing thrust and a steel can bell, and you'll be talking converter tuneup options, using dump valves. It'll sound like a three or four speed transmission going down through there.

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

Needle bearing thrust and a steel can bell???

quote:

Originally posted by markemark:
^^^^^ http://www.rosslertrans.com/on...05/category=40293040

Bob Gulitti was testing that exact dump valve this past weekend on his low 6 sec TS car

quote:

Originally posted by Greg Kelley:
Converter. My Select/Coan 258 slips around 1.5%. Here's another Select/Coan going into overdrive.

The overdirve is actually pretty common in Top Sportsman cars.

The turbine passed the pump eh? Wouldn't the rate of engine rpm increase be more profoundly observable diminishing, if the turbine passed the pump? I'm not saying one way or the other but curious if ya'll have verified this data by other means. Clearly the converter is stout. Either way it's interesting.

PTC does a bunch of turbo stuff. All of the turbo cars prefer a converter that is loose enough to let the non boosted engine get some rpm, but tight down track so the boosted power doesn’t blow through it. They seem to know the tricks and got mine pretty close first time.

quote:
Originally posted by Greg Kelley:
Converter. My Select/Coan 258 slips around 1.5%. Here's another Select/Coan going into overdrive.

The overdirve is actually pretty common in Top Sportsman cars.



The turbine passed the pump eh? Wouldn't the rate of engine rpm increase be more profoundly observable diminishing, if the turbine passed the pump? I'm not saying one way or the other but curious if ya'll have verified this data by other means. Clearly the converter is stout. Either way it's interesting.

been there done that but it always seems to loose et.mike it will do that ,i have a friend that has super gas car that doesit also.i still prefer aound 3%for optimum et and mph.right now mine is too loose in summer not too bad.lol i am too lazy to change stators.this is the best of both worlds at this point

Hypothetically speaking, If you have a converter the turbine rpm is passing the pump rpm, give it more final gear and the turbine will pass the pump sooner and you'll go faster, without increasing the finish line rpm depending on how much sooner the turbine pass's pump and by how many rpm's! I'm still somewhat skeptical this is happening, so I attached hypothetically to this thesis!

mike i was skeptical too at first but it does happen,however by simply adding gear,load ect if you dont add power you will loose rpm and with that you slow down.

greg kelley has tested this gear thing from one end to the other, by the way.

As long as the engine rpm isn't increasing at a higher rate than the torque of the engine is diminishing, you're making power.

When you add gear you are adding power at the back tire.

I'm not skeptical according to racepak graphs there are turbines passing pumps. I'm somewhat skeptical it is happening within torque converters. Otherwise someone would have already figured out to add gear to make it happen sooner in order to go faster without an increase in finish line rpm! Hypothetically speaking!

i think they have its called lock up converters,there was alocal around here that had one years ago,cant rememberall of the details but it was very unique back then

Damn rpm's always a stumbling block rusty. Not with this one though. We might not win but we'll have the most rpm's in the race, so it won't be for a lack of trying.

lol i believe you will

quote:

Originally posted by jenavet:
Needle bearing thrust and a steel can bell???

Yes, If you see one in the lanes, it is a racer using dump valves to tune the torque converter, most likely. A conventional thrust is designed for safely coping with 125 psi converter pressures aside from spikes in pressure. A needle bearing thrust opens up the option for additional pressure, equaling a bigger window of torque converter tuning using dump valves on both sides of the converter.

It's the next big thing boosted. Three and four speed powerglide transmissions. If you know the fundamentals it'll be a piece of cake in terms of burning less fuel testing. Input shaft plus stator tube design plays a role.

Jennn...where does the G meter dive or does it?