964 engine stall with lightweight flywheel
#1
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Well, the 3.6L is in the car and it is impressive. Tremendous torque ... the car pulls up to 7000rpm redline. The accelerator pedal is different, very light to the touch. I understand the accelerator connection with the 3.6 is different from the 3.2L.
Now, for the "hiccup". There is some stalling with the lightened flywheel as the revs drop very quickly. But, if I'm careful (remember I just road tested the car for the first time this evening), with a alittle heel-toeing (a skill I am still trying to learn), I can avoid stalling.
There are a few different "cures" we are considering to solve the idle stalling:
(1) switching back to the heavy duty pressure plate, allowing inertia to slow the rapid drop in revs; (2) "tricking" the computer into thinking that the AC is "on" (the AC has been removed from the car), which increases the revs by about 150rpm; (3) installing a weltmeister chip - perhaps resulting in a higher idle; (4) installing a "remapped" idle stablization valve. I've heard this may be available through Windward (and maybe other suppliers), but don't know whether it works on an '89 964 3.6L engine.
Any ideas?
To me, the car now feels "turbo fast", but without any "turbo lag". The engine pulls from the bottom revs right up past the "old" redline - the way we built this engine shifting at 7000 is safe (after bending all the valves in the 3.2L, believe me, I'll be careful).
With the Web Cams "993 supersport" cams, the exhaust note has just enough "roughness", a little "growl" and a slightly deeper sound.
I will attempt to post pictures next week.
The installation is extremely clean and looks "right on"; oh yes, I have heat!
Now I'm just hoping that the weather holds here in New York through this weekend so I can become reaquainted with my "new" old friend. The "Red Sled" returns!
Richard
'87 Carrera 3.6L
Now, for the "hiccup". There is some stalling with the lightened flywheel as the revs drop very quickly. But, if I'm careful (remember I just road tested the car for the first time this evening), with a alittle heel-toeing (a skill I am still trying to learn), I can avoid stalling.
There are a few different "cures" we are considering to solve the idle stalling:
(1) switching back to the heavy duty pressure plate, allowing inertia to slow the rapid drop in revs; (2) "tricking" the computer into thinking that the AC is "on" (the AC has been removed from the car), which increases the revs by about 150rpm; (3) installing a weltmeister chip - perhaps resulting in a higher idle; (4) installing a "remapped" idle stablization valve. I've heard this may be available through Windward (and maybe other suppliers), but don't know whether it works on an '89 964 3.6L engine.
Any ideas?
To me, the car now feels "turbo fast", but without any "turbo lag". The engine pulls from the bottom revs right up past the "old" redline - the way we built this engine shifting at 7000 is safe (after bending all the valves in the 3.2L, believe me, I'll be careful).
With the Web Cams "993 supersport" cams, the exhaust note has just enough "roughness", a little "growl" and a slightly deeper sound.
I will attempt to post pictures next week.
The installation is extremely clean and looks "right on"; oh yes, I have heat!
Now I'm just hoping that the weather holds here in New York through this weekend so I can become reaquainted with my "new" old friend. The "Red Sled" returns!
Richard
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'87 Carrera 3.6L
#2
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Steve Timmins sells a Cyntex chip programmed to address this.
There was also a factory Cup/RS chip that did the same thing.
There was a guy selling the Windward ISV in the rennlist classifieds, recently. It may be the cheapest option for your application.
Cyntex Chips with idle code, $325 with kit:
* The factory chips have a fuel cut algorithm to bring the car down to idle with the massive dual mass flywheel (40 Lbs). When the factory chips are used with a lightweight flywheel (as supplied), and especially with a lightweight clutch pack (such as the Sachs Power Kit clutch pack) the engine has a tendency to stall when dropping down to idle.
* The specially designed Cyntex chips have a special idle deceleration code that eliminates this problem and raises idle to 850 RPM and redline to 6800.
*
* The factory chips have a fuel cut algorithm to bring the car down to idle with the massive dual mass flywheel (40 Lbs). When the factory chips are used with a lightweight flywheel (as supplied), and especially with a lightweight clutch pack (such as the Sachs Power Kit clutch pack) the engine has a tendency to stall when dropping down to idle.
* The specially designed Cyntex chips have a special idle deceleration code that eliminates this problem and raises idle to 850 RPM and redline to 6800.
*
There was a guy selling the Windward ISV in the rennlist classifieds, recently. It may be the cheapest option for your application.
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Hi Richard,
Welcome to the wonderful world of stalling lightweight flywheel (LWF) equipped 3.6L 911s! If you had spent much time on the 964 or 993 board in the past, you surely would have seen this coming
.
All the '90-95 964/993s are susceptible to stalling when a LWF is installed. VRAM/OBDII owners that install LWFs don't seem to have stalling problems--OBDII apparently handles the mod. without trouble.
To correct your stalling, you can:
1) Reinstall the heavy flywheel (as you suggest).
2) Install Andial's semi-LWF, which has weight added back on to cure the stalling and simplify launching the car.
3) Modify the idle stabilizer valve (as you suggest).
4) Install a chip that compensates for the LWF in its software (as you suggest).
Considering that your A/C is removed, your idea of tricking the DME into thinking the A/C is always on might work. Based on my own LWF experience, I don't think it would work if you actually had functional A/C--my idle used to be horribly erratic when I ran the A/C.
I believe Andial can add their weight to your existing LWF, if you decide to go that route.
If you decide to purchase a chip to cure your idle problems, I would recommend getting it from Steve Weiner at Rennsport. Very knowledgeable on the subject, and I'm sure he wouldn't leave you stuck with a product that doesn't work.
Best of luck!
Welcome to the wonderful world of stalling lightweight flywheel (LWF) equipped 3.6L 911s! If you had spent much time on the 964 or 993 board in the past, you surely would have seen this coming
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
All the '90-95 964/993s are susceptible to stalling when a LWF is installed. VRAM/OBDII owners that install LWFs don't seem to have stalling problems--OBDII apparently handles the mod. without trouble.
To correct your stalling, you can:
1) Reinstall the heavy flywheel (as you suggest).
2) Install Andial's semi-LWF, which has weight added back on to cure the stalling and simplify launching the car.
3) Modify the idle stabilizer valve (as you suggest).
4) Install a chip that compensates for the LWF in its software (as you suggest).
Considering that your A/C is removed, your idea of tricking the DME into thinking the A/C is always on might work. Based on my own LWF experience, I don't think it would work if you actually had functional A/C--my idle used to be horribly erratic when I ran the A/C.
I believe Andial can add their weight to your existing LWF, if you decide to go that route.
If you decide to purchase a chip to cure your idle problems, I would recommend getting it from Steve Weiner at Rennsport. Very knowledgeable on the subject, and I'm sure he wouldn't leave you stuck with a product that doesn't work.
Best of luck!
#4
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Randall is right on...ANDIAL sell a light weight flywheel with additional weight added, not much, but enough to address the stalling problem, or so I am told. It works well on the early 993 motors with OBD I electronics. The later 993 cars with OBD II electronics can handle the lighter flywheel without stalling, or so I am told onvce again. Call Pete Wetzel at ANDIAL if you want more info. They are in Santa Ana, CA.
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#6
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Enlist the help of a friend to make sure you have full accelerator travel so you're tripping the WOT switch. Mine wasn't one I first got it back.
Got pix?
What'd you use for an exhaust?
A very satisfying conversion, isn't it?
Got pix?
What'd you use for an exhaust?
A very satisfying conversion, isn't it?
Originally posted by richglickel:
<STRONG>The accelerator pedal is different, very light to the touch. I understand the accelerator connection with the 3.6 is different from the 3.2L.
</STRONG>
<STRONG>The accelerator pedal is different, very light to the touch. I understand the accelerator connection with the 3.6 is different from the 3.2L.
</STRONG>
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My opinion is to go the chip route...talk to Steve Weiner @Rennsport Systems, he'll hook you up.
The flywheel mod would mean taking your engine/trans. out again...I believe, unless they have some neat trick to install this weight? It's possible.![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
The Idle Stabilization Valve is @ $300 modified, from Windward...so for another $100 or so you get a custom burned chip for your application that can yield gains of up to 23HP...what can you lose?? Mine is enroute.
Talk to Steve W. - you won't regret it. ![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
...just trying to use a little reasoning to help you make a decision - you seem to like that extra "umph"!!
The flywheel mod would mean taking your engine/trans. out again...I believe, unless they have some neat trick to install this weight? It's possible.
![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
The Idle Stabilization Valve is @ $300 modified, from Windward...so for another $100 or so you get a custom burned chip for your application that can yield gains of up to 23HP...what can you lose?? Mine is enroute.
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
...just trying to use a little reasoning to help you make a decision - you seem to like that extra "umph"!!
![EEK!](https://rennlist.com/forums/images/smilies/eek.gif)
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#8
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Jack, Thom, Jeff, et al.,
Thanks to you all. We're working on it as I write this. Since just about everything is together and the car is up and running, I think we'll opt for the chip (maybe get alittle more hp too; don't need more torque (hee, hee).
I shall report results and, eventually, provde pix of installation.
You guys are the best. Thanks, again.
Richard
'87 Carrera 3.6L
Thanks to you all. We're working on it as I write this. Since just about everything is together and the car is up and running, I think we'll opt for the chip (maybe get alittle more hp too; don't need more torque (hee, hee).
![Stick Out Tongue](https://rennlist.com/forums/images/smilies/tongue.gif)
I shall report results and, eventually, provde pix of installation.
You guys are the best. Thanks, again.
Richard
'87 Carrera 3.6L
![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)