DMF vs SMF
Thread Starter
Instructor
Joined: Mar 2009
Posts: 122
Likes: 6
DMF vs SMF
I was wondering if a different clutch is needed with a DMF vs. a SMF. If say the DMF is 3" thick and the SMF is only 1/2" thick (these are examples as I have no idea as to the actual numbers) how does the clutch work with the difference in thickness? I have a 96 and my mechanic ordered the clutch first and then the SMF after realizing that the DMF was shot. I've had occassional trouble with burning smell in the clutch each time I drive up my driveway and into my garage. Its not to steep, but obviously I have to feather the clutch as I go into the garage. Once when downshifting I had a lot of smoke come up from the shifter. That was only about 300 miles after the new clutch and SMF was put in. I have been unhappy with the SMF (noise, etc) and he has offered to replace it a no labor cost with the DMF. Its only been 1000 miles since this new setup was put in. So I have to make the decision if I want to spend for the cost of the DMF alone. What would be causing the occassional clutch burning smell? Should I insist on a new clutch if I go with the new flywheel? Thanks for the help and advise. This is my first C4.
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Assuming he used an LT1 pull style clutch and a C4 specific SMF, it's the same clutch. The front face of the flywheel ends up in the same place.
Last edited by Mojave; Aug 15, 2009 at 03:05 PM.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
I was wondering if a different clutch is needed with a DMF vs. a SMF. If say the DMF is 3" thick and the SMF is only 1/2" thick (these are examples as I have no idea as to the actual numbers) how does the clutch work with the difference in thickness? I have a 96 and my mechanic ordered the clutch first and then the SMF after realizing that the DMF was shot. I've had occassional trouble with burning smell in the clutch each time I drive up my driveway and into my garage. Its not to steep, but obviously I have to feather the clutch as I go into the garage. Once when downshifting I had a lot of smoke come up from the shifter. That was only about 300 miles after the new clutch and SMF was put in. I have been unhappy with the SMF (noise, etc) and he has offered to replace it a no labor cost with the DMF. Its only been 1000 miles since this new setup was put in. So I have to make the decision if I want to spend for the cost of the DMF alone. What would be causing the occassional clutch burning smell? Should I insist on a new clutch if I go with the new flywheel? Thanks for the help and advise. This is my first C4.
What's as important IMO, is to use a sprung-hub clutch with a SMF vs the non-sprung unit that mates with the DMF. That's helps absorb noise/rattle.
Carolina Clutch is a good source for the SMF setup. Not sure you can even get a DMF -- if so, they probably want $1200. Using the "forum discount", you might be able to get one for $950ish thru Superior -- if they still have 'em.
Team Owner
Joined: Aug 2005
Posts: 34,988
Likes: 515
From: Riverside County Southern California
Co-winner 2020 C4 of the Year - Modified
2018 Corvette of Year Finalist
2017 C4 of Year
2016 C7 of Year Finalist
St. Jude Donor '09 thru '20
Amazingly, the DMF is becoming the new "Opti Spark" 
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Thread Starter
Instructor
Joined: Mar 2009
Posts: 122
Likes: 6
DMF vs SMF
So what is the difference between a Sprung hub clutch vs. an Unsprung and what would the impact of the unsprung with the SMF. Would that be causing the slipage and the occasional burning smell in the clutch? Thanks
Melting Slicks
Joined: Oct 2006
Posts: 2,238
Likes: 10
From: College Station TX
A sprung hub has springs in it to soften up big shocks. An unsprung does not. Running an unsprung could cause a bit more harshness on hard launches.
