3.6 guys - Do you have a lightweight flywheel? has anyone switched back to factory?

[JonT]

Wondering if switching back to factory size flywheel would help drivability? Currently with the hot cam (993 SS) and lightweight flywheel the clutch is very fussy and bucks in 1st gear without a lot of clutch feathering. What is causing this and is there a known fix?

[Bill Verburg]

Originally Posted by JonT

Wondering if switching back to factory size flywheel would help drivability? Currently with the hot cam (993 SS) and lightweight flywheel the clutch is very fussy and bucks in 1st gear without a lot of clutch feathering. What is causing this and is there a known fix?

all of the conversion 915 flywheels are l/w compared to ta stock 964/993 dual mass flywheel

what clutch are you using?

when I had a racing clutch in mine it was like an on/off switch, great for track use not so much in traffic, Now using an al. Sachs sport clutch which is a pleasure even w/ RS cams

[icarp]

bucking has to do with the mixture .
It is normally too lean

Ian

[stownsen914]

I'm not able to comment on OP's specific setup, but depending on how we are defining "bucking'" I'd say it can happen with a lightweight flywheel and clutch. In cars I've driven with lightweight clutches, it's hard to get the car to settle into a steady cruise state in the lower gears - always adjusting throttle up or down to maintain a speed. Even worse with a smaller diameter clutch. More weight on the flywheel/clutch assembly can help smooth this out.

Releasing the clutch to get rolling can be challenging too of course. Above I'm referring to when the car is already rolling.

Mixture being off can cause bucking as well.

[JonT]

Originally Posted by Bill Verburg

all of the conversion 915 flywheels are l/w compared to ta stock 964/993 dual mass flywheel

what clutch are you using?

when I had a racing clutch in mine it was like an on/off switch, great for track use not so much in traffic, Now using an al. Sachs sport clutch which is a pleasure even w/ RS cams

I'm using a Sachs sport clutch. I'll investigate the mixture as well.

[PeteKz]

Agree with ICarp. Your mixture probably is too lean, or you have vacuum leaks. That said, a heavier flywheel/clutch will improve drivability.

[blucille]

If it’s a 3.6 from 993 or 964 with fuel injection it doesn’t seem like there would be much you can do to adjust mixture. But a vacuum leak would be the more likely cause.

What did the motor come out of. The plastic intake boots and rubber couplers can be a cause of vacuum leaks.

I’ve been listening to the latest jason Cammisa podcast and Derek tam Scott mentioned his car and his dad’s car both had some similar issues that you (and I) are suffering from. Mine are highly intermittent- and both ECU’s needed to be rebuilt. His dad’s car has been flawless since and when he swapped that ecu into his car, it was also perfect. His ECU is on its way back from being rebuilt.

I wouldn’t bother sending to Dave/Loren, so I’m looking for a trusted vendor to take a look

[JonT]

thanks guys. Blucille let me know where you end up getting your ecu rebuilt please.

[mysocal911]

Originally Posted by blucille

If it’s a 3.6 from 993 or 964 with fuel injection it doesn’t seem like there would be much you can do to adjust mixture. But a vacuum leak would be the more likely cause.

What did the motor come out of. The plastic intake boots and rubber couplers can be a cause of vacuum leaks.

I’ve been listening to the latest jason Cammisa podcast and Derek tam Scott mentioned his car and his dad’s car both had some similar issues that you (and I) are suffering from. Mine are highly intermittent- and both ECU’s needed to be rebuilt. His dad’s car has been flawless since and when he swapped that ecu into his car, it was also perfect. His ECU is on its way back from being rebuilt.

I wouldn’t bother sending to Dave/Loren, so I’m looking for a trusted vendor to take a look

The 964/993 DME ECMs are rarely, if ever, intermittent. Guess again!

[blucille]

Thanks Loren / Dave. That’s why I’d like to find the right person to send it to.

[Bill Verburg]

ECU Docs in Fla. did mine, quick turnaround and they did a great job, I was impressed w/ their knowledge of some of the nuances involved w/ the different chips that can be used.

[blucille]

Originally Posted by Bill Verburg

ECU Docs in Fla. did mine, quick turnaround and they did a great job, I was impressed w/ their knowledge of some of the nuances involved w/ the different chips that can be used.

That’s great to hear, Bill.

What were the symptoms of you needing to send it out? Intermittent ????

[rumlyne]

For Bill V.
do you have a phone number for ecu docs?
Their form doesn't fit a conversion ecu and I'm hesitant to blindly give someone my credit card info as requested on their repair form
A 2 minute phone conversion is better than incessant typing and hope.
I don't post much on here but have been here since 2007 and always
pay great attention to your posts. You and Jack Olson were the motivation
to build this car.

Thanks

[rumlyne]

I did my conversion back in 2012. I also have the light weight flywheel
with the sachs alu sport clutch package and have had no issues except the
usual occasional stall.

[avenbugt]

Originally Posted by rumlyne

I did my conversion back in 2012. I also have the light weight flywheel
with the sachs alu sport clutch package and have had no issues except the
usual occasional stall.

Same for me! Since 2008. No issues.
Advise: don't drive with heavy work shoes! Best is with light shoes where you can feel the accelerator...

[Bill Verburg]

Originally Posted by blucille

That’s great to hear, Bill.

What were the symptoms of you needing to send it out? Intermittent ????

when I hit a bump in the road everything cycled off then back on

The cold solders are the primary culprit

when I bought my 993 it had an RS solid l/w flywheel and wound occasionally stall w/ AC on coming to a stop, SW chip solved that issue