Fuddle Racing
The point is to not to go up in smoke at a light next to a stang. I got a 1.9 STR with mine and love it. My buddy has a 2.5 and it plain sucks. The tires go up in smoke anytime he tries to get on it. He's a H/C car and I'm not and I'll hole shot him everytime because of that. I didn't want to end up like him after my cam this summer.
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I understand the concept of STR. I just know anything past quarter throttle and his tires melt and I don't want to be in that boat. What's the point of having the power if you can't put it to the ground? I'll deal with a little looseness (which isn't bad at all) to be able to hook on the street.
Originally Posted by 0rion
The point is to not to go up in smoke at a light next to a stang.
The other thing about big STR is, it multiplies not at all
down low in RPM, hits big time out of the hole and quits
multiplying early. That's swell for a strip car on slicks.
In traffic, a car with a 1.8 STR will cruise unlocked at
1500RPM and 2.5 STR more like 2500, making heat all
the while.
The 1.8 car, with the same nominal stall speed, will
still be multiplying torque when the 2.5 is doen to
1:1. The STR above what your tires were able to
hook up is wasted pretty much and has its cost.
It's easier to get high efficiency out of a lower STR
pump/stator combo than out of a high one. So up top
you might see 97% instead of 94% efficiency and that
is about +10HP to the ground.
down low in RPM, hits big time out of the hole and quits
multiplying early. That's swell for a strip car on slicks.
In traffic, a car with a 1.8 STR will cruise unlocked at
1500RPM and 2.5 STR more like 2500, making heat all
the while.
The 1.8 car, with the same nominal stall speed, will
still be multiplying torque when the 2.5 is doen to
1:1. The STR above what your tires were able to
hook up is wasted pretty much and has its cost.
It's easier to get high efficiency out of a lower STR
pump/stator combo than out of a high one. So up top
you might see 97% instead of 94% efficiency and that
is about +10HP to the ground.
Originally Posted by jimmyblue
In traffic, a car with a 1.8 STR will cruise unlocked at
1500RPM and 2.5 STR more like 2500, making heat all
the while.
1500RPM and 2.5 STR more like 2500, making heat all
the while.
Originally Posted by sleeperstyle
i thought 1.8 would be mushier generating higher cruising rpms (unlocked) and temps? or did you accidentally switch them around?
a few people report that the old 1.6 str yank was very mushy.
The lower the STR the wider the range of coupling. If you
are cruising at very light torque the low-STR converter
will have less slip than the high STR. The Yank site used
to have nice pictures of this. The more torque you push
the more a low-STR converter's RPM will slide. This is what
people call "mushy". But a high-STR converter won't couple
much at all until you get closer-in to the stall speed. Then
it has a harder coupling slope and feels "tight" - but only
when your RPMs are up there.
are cruising at very light torque the low-STR converter
will have less slip than the high STR. The Yank site used
to have nice pictures of this. The more torque you push
the more a low-STR converter's RPM will slide. This is what
people call "mushy". But a high-STR converter won't couple
much at all until you get closer-in to the stall speed. Then
it has a harder coupling slope and feels "tight" - but only
when your RPMs are up there.
TECH Enthusiast
Joined: Mar 2004
Posts: 647
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From: Australia
Thats right. Lower STR multiples the TQ over more of the slip RPM band. Higher STR multiplies TQ over a much shorter RPM band which is closer to the stall speed. As a result it comes on harder and shocks the tyres more. Higher STR converters are better for track work, lower STR converters for the street and cruising/fuel economy.
But thats not all. STR is coupled to the stall speed. So a 3000/2.0STR converter would perform similar to a 3500/1.6STR for street manners but feel much tighter around 2500RPM - the usual driving RPM for street cars.
The other trade off is shift extension. The higher the STR usually the less efficient the converter is. However, the less the RPM drop between shifts thereby keeping you in the power band. These converters perform better at the track.
Finally the converter needs to be matched to the overall setup of your car. Things to consider are:
diff ratio & tyre size
max flywheel horsepower
power band of the motor
driving style/needs (track or street or both)
how you want it to feel
The last point is very subjective which is why you always hear posts like "I have a 4200 TCI and it has great street manners" to "I have a Yank 3500 and it feels too mushy" to "I have a nitrous 2800 converter and I cant get traction".
John from Fuddle racing can help you further with your questions. He is a sponsor here.
But thats not all. STR is coupled to the stall speed. So a 3000/2.0STR converter would perform similar to a 3500/1.6STR for street manners but feel much tighter around 2500RPM - the usual driving RPM for street cars.
The other trade off is shift extension. The higher the STR usually the less efficient the converter is. However, the less the RPM drop between shifts thereby keeping you in the power band. These converters perform better at the track.
Finally the converter needs to be matched to the overall setup of your car. Things to consider are:
diff ratio & tyre size
max flywheel horsepower
power band of the motor
driving style/needs (track or street or both)
how you want it to feel
The last point is very subjective which is why you always hear posts like "I have a 4200 TCI and it has great street manners" to "I have a Yank 3500 and it feels too mushy" to "I have a nitrous 2800 converter and I cant get traction".
John from Fuddle racing can help you further with your questions. He is a sponsor here.
Originally Posted by MNR-0
Thats right. Lower STR multiples the TQ over more of the slip RPM band. Higher STR multiplies TQ over a much shorter RPM band which is closer to the stall speed. As a result it comes on harder and shocks the tyres more. Higher STR converters are better for track work, lower STR converters for the street and cruising/fuel economy.
But thats not all. STR is coupled to the stall speed. So a 3000/2.0STR converter would perform similar to a 3500/1.6STR for street manners but feel much tighter around 2500RPM - the usual driving RPM for street cars.
The other trade off is shift extension. The higher the STR usually the less efficient the converter is. However, the less the RPM drop between shifts thereby keeping you in the power band. These converters perform better at the track.
Finally the converter needs to be matched to the overall setup of your car. Things to consider are:
diff ratio & tyre size
max flywheel horsepower
power band of the motor
driving style/needs (track or street or both)
how you want it to feel
The last point is very subjective which is why you always hear posts like "I have a 4200 TCI and it has great street manners" to "I have a Yank 3500 and it feels too mushy" to "I have a nitrous 2800 converter and I cant get traction".
John from Fuddle racing can help you further with your questions. He is a sponsor here.
But thats not all. STR is coupled to the stall speed. So a 3000/2.0STR converter would perform similar to a 3500/1.6STR for street manners but feel much tighter around 2500RPM - the usual driving RPM for street cars.
The other trade off is shift extension. The higher the STR usually the less efficient the converter is. However, the less the RPM drop between shifts thereby keeping you in the power band. These converters perform better at the track.
Finally the converter needs to be matched to the overall setup of your car. Things to consider are:
diff ratio & tyre size
max flywheel horsepower
power band of the motor
driving style/needs (track or street or both)
how you want it to feel
The last point is very subjective which is why you always hear posts like "I have a 4200 TCI and it has great street manners" to "I have a Yank 3500 and it feels too mushy" to "I have a nitrous 2800 converter and I cant get traction".
John from Fuddle racing can help you further with your questions. He is a sponsor here.
Full bolt-ons, 3.73's, built tranny W/shift kit/cooler, and a XE 230/236 cam...with nittos eventually..
Its daily driven, but not far, Im looking for the best possible track times, but also descent streetability for racing/daily driving..
I think too many people have the "cam syndrome" when it comes to car parts. Just as in selecting cams people tend to look at the numbers and think "bigger is better". That's not always the case. I have my goals set which are pretty meager by most peoples standards and I'm putting together the best possible set up to reach that goal. Sure I'd like to put down 500 HP just like the next guy but do I need that much and what am I giving up to get it? That's more what I look at versus just numbers.
Originally Posted by 0rion
I think too many people have the "cam syndrome" when it comes to car parts. Just as in selecting cams people tend to look at the numbers and think "bigger is better". That's not always the case. I have my goals set which are pretty meager by most peoples standards and I'm putting together the best possible set up to reach that goal. Sure I'd like to put down 500 HP just like the next guy but do I need that much and what am I giving up to get it? That's more what I look at versus just numbers.
mine is a 2.55 str stall. It works perfect as a daily driver. 12k miles infact. If your in the county your in lockup as much or more than when your below lockup speeds.
In terms of blowing the tires off I usually roll on the gas to avoid that.
does a lower str have a higher or lower shift extension for a given power range?
In terms of blowing the tires off I usually roll on the gas to avoid that.
does a lower str have a higher or lower shift extension for a given power range?