LWF on a Turbo Car - INSTALLED !
08-25-2010, 12:06 PM
#1
Three Wheelin'
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LWF on a Turbo Car - INSTALLED !
Hello
I am just trying to get some thoughts from the experts. I did speak to a few rlisters, but have received conflicting info. This post should not by any means show disrespect to the fellow rennlisters that have given their direct advice already.
Question:
Would a LWF mod on a turbo car make sense (cost vs benefit)? Do I have to reflash the ECU? Also, what thickness should the Flywheel be as there is a risk of breaking if to thin/light.
TIA
I am just trying to get some thoughts from the experts. I did speak to a few rlisters, but have received conflicting info. This post should not by any means show disrespect to the fellow rennlisters that have given their direct advice already.
Question:
Would a LWF mod on a turbo car make sense (cost vs benefit)? Do I have to reflash the ECU? Also, what thickness should the Flywheel be as there is a risk of breaking if to thin/light.
TIA
Last edited by tjangi; 09-19-2010 at 02:50 PM.
08-25-2010, 12:22 PM
#2
RL Technical Advisor
JMHO,........
LWF's on Turbo cars work really well. Naturally, you must package that with the correct clutch package for durability. The LWF is far more reliable than the Dual-Mass one.
No specific ECU flash is necessary; it will adapt very easily.
Just use the Factory RS LWF along with a proper clutch kit and you'll have no issues. Those are quite trouble free.
LWF's on Turbo cars work really well. Naturally, you must package that with the correct clutch package for durability. The LWF is far more reliable than the Dual-Mass one.
No specific ECU flash is necessary; it will adapt very easily.
Just use the Factory RS LWF along with a proper clutch kit and you'll have no issues. Those are quite trouble free.
08-25-2010, 01:03 PM
#3
Three Wheelin'
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Steve, do the RS LWF come in different weights? And if so, which ones? Also since my car is a 95, do I need to worry about stalling issues? Thank you.
08-25-2010, 04:37 PM
#4
Rennlist Member
Gappy, +1 on what Steve said.
No different flywheel is needed. Only 1 LWF available (OE)
Not sure on the stalling concerns. You'd need to check with Protomotive on the programming you have an it's tolerance for this sort of thing.
There are a couple of choices on the pressure plate. I'd go with the higher clamp force, even if your Torque output allows for the lighter duty version
From personal experience, I can tell you I have been very happy with mine. The quicker revs are very nice.
No different flywheel is needed. Only 1 LWF available (OE)
Not sure on the stalling concerns. You'd need to check with Protomotive on the programming you have an it's tolerance for this sort of thing.
There are a couple of choices on the pressure plate. I'd go with the higher clamp force, even if your Torque output allows for the lighter duty version
From personal experience, I can tell you I have been very happy with mine. The quicker revs are very nice.
08-25-2010, 09:32 PM
#5
Rennlist Member
Very happy with mine as you know Gappy...however, with your's being a 95 the stalling issue lingers...I recall it only happened to some rennlisters with 95's ..not all...
08-25-2010, 10:45 PM
#6
RL Technical Advisor
Fact is, some 95's can stall with the thing and others adapt very well with little or no drama. Personally, I think the variation is due to many little things such as worn ISV's, little vacuum leaks, dirty MAFS and throttle, etc. The reality is most of these cars have accumulated miles on them over the years and everything shows the effects of that.
When we do a proper rebuild, they rarely ever stall with the LWF,...
If everything is "right", they are pretty good. Good performance software makes them a little more stall-proof, but sometimes not perfect depending on the above variables.
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08-26-2010, 01:31 AM
#8
Three Wheelin'
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I found this article about the LWF mod with the caveat on 95 build Pcars. Sorry for the long post. But at the end of the article it is mentioned that one can "tweak" the ISV to avoid stalling. How easy is it to do this?
RS clutch and LW flywheel
December 15th, 2002 · 2 Comments
The lightweight flywheel (LWF) is a great way to improve the quickness of your 993 and make the car more fun to drive. A normal 993 uses a “dual mass” flywheel and clutch (think of it as two pieces of metal with a rubber layer between them). While it generally works fine, the rubber can fail.
The RS version of the 993 used a different flywheel that weighs about 30% less than the standard flywheel and it’s one piece of metal with no rubber to fail. Less weight means an engine that revs faster, with most noticable improvements in the lower gears. When replacing the dual mass with the lightweight flywheel the clutch must also be replaced.
This is a great change to make if you need a new clutch or your dual mass flywheel fails. It will cost about $1800 for the new parts. To remove the transmission to allow the clutch flywheel change will cost about $1000.
There can be an issue with making this change with 1995 993s as the engine management is not as sophisticated as on the ‘96 to ‘98 cars (see OBDI vs OBD II). Since the flywheel weighs less it allows the engine to rev faster. This also means that the revs drop faster when you shift. On a ‘95, if you disengage the clutch the revs can drop so fast the car stalls. The higher the rpm when you diengage the clutch the more likely it is for the car to stall. There is a fix for this problem. The ISV (idle stabilizer valve) can be tweeked to eliminate the stalling. Changing the car ECU chip can also help (its a great reason to “have to” upgrade the chip).
Since you don’t have the rubber to strech and contract, the transmission is a bit noisier with the LWF than standard. This bothers some people.
December 15th, 2002 · 2 Comments
The lightweight flywheel (LWF) is a great way to improve the quickness of your 993 and make the car more fun to drive. A normal 993 uses a “dual mass” flywheel and clutch (think of it as two pieces of metal with a rubber layer between them). While it generally works fine, the rubber can fail.
The RS version of the 993 used a different flywheel that weighs about 30% less than the standard flywheel and it’s one piece of metal with no rubber to fail. Less weight means an engine that revs faster, with most noticable improvements in the lower gears. When replacing the dual mass with the lightweight flywheel the clutch must also be replaced.
This is a great change to make if you need a new clutch or your dual mass flywheel fails. It will cost about $1800 for the new parts. To remove the transmission to allow the clutch flywheel change will cost about $1000.
There can be an issue with making this change with 1995 993s as the engine management is not as sophisticated as on the ‘96 to ‘98 cars (see OBDI vs OBD II). Since the flywheel weighs less it allows the engine to rev faster. This also means that the revs drop faster when you shift. On a ‘95, if you disengage the clutch the revs can drop so fast the car stalls. The higher the rpm when you diengage the clutch the more likely it is for the car to stall. There is a fix for this problem. The ISV (idle stabilizer valve) can be tweeked to eliminate the stalling. Changing the car ECU chip can also help (its a great reason to “have to” upgrade the chip).
Since you don’t have the rubber to strech and contract, the transmission is a bit noisier with the LWF than standard. This bothers some people.
08-26-2010, 12:34 PM
#11
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I think most of the stalling issues can be attributed to the driver.
DMFs are very forgiving. You can practically side-step the clutch at idle and not stall because it soaks up a
bunch of torque at engagement, and has a tremendous amount of rotating mass.
However, the LWF doesn't soak up the torque, it just transfers it to the trans. And there is very little rotating
mass as well. If you're a little light on the throttle, or a little to quick to engage, you're probably going to stall.
The DMFs spoil us, and we have to learn how to drive all over again with the LWFs.
--Chuck--
DMFs are very forgiving. You can practically side-step the clutch at idle and not stall because it soaks up a
bunch of torque at engagement, and has a tremendous amount of rotating mass.
However, the LWF doesn't soak up the torque, it just transfers it to the trans. And there is very little rotating
mass as well. If you're a little light on the throttle, or a little to quick to engage, you're probably going to stall.
The DMFs spoil us, and we have to learn how to drive all over again with the LWFs.
--Chuck--
08-26-2010, 04:42 PM
#13
Rennlist Member
the stalling issue people are usually concerned with on the earlier 993s is the rolling-to-a-stop-clutch-in sort of stall.
The idle drops too low too fast and... the engine stalls.
As previously said, there are ways to deal with it IF it does happen after the LWF install
The idle drops too low too fast and... the engine stalls.
As previously said, there are ways to deal with it IF it does happen after the LWF install
09-19-2010, 02:49 PM
#15
Three Wheelin'
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RS LWF is installed and summary of of findings:
1. Engine response from stand still 100% faster
2. Car pulls faster
3. Stalled 2X, but otherwise no issues. ECU seems to have adapted to the faster dropping RPM and 99% manages to ref the engine by itself to avoid stalling
4. I can hear the FL at idle, but it does not bother me
Well worth mod IMHO. Thanks for everyone's input and push to the next level of slippery slope.
Special tx to the FDM boys as well
1. Engine response from stand still 100% faster
2. Car pulls faster
3. Stalled 2X, but otherwise no issues. ECU seems to have adapted to the faster dropping RPM and 99% manages to ref the engine by itself to avoid stalling
4. I can hear the FL at idle, but it does not bother me
Well worth mod IMHO. Thanks for everyone's input and push to the next level of slippery slope.
Special tx to the FDM boys as well