Can't shift fast at high rpm?

[AREA 91]

I have been having this problem for a while now.
The higher I rev the engine, the longer it takes to grab the next gear.

Example:

I can shift instantly at 3000 RPM, but it takes 3 seconds at 6000 RPM.
WHY???

Is it the combination of the Fidanza aluminum flywheel coupled to a Clutch Master's Stage III clutch?

I have talked to a few senior member's on here, and there seems to be a debate that the pressure plate is "too strong" for the aluminum flywheel. The flywheel might be "flexing" at high rpm and that is making it hard to shift.

Does this make sense?

Why can I rip through the gears at low rpm's, but the higher I rev it, the longer it takes to shift.

Sugguestions???
1 New clutch cable
2 New clutch quadrant
3 Different tranny fluid
4 Ditch the aluminum flywheel, and replace it with a steel billet.

I open the floor for discussion to you lady's and gentlemen.

P.S. My SHO has done this since I put the flywheel and clutch in 2 years ago. No wonder I can't run a 12 second ET!

The Convention is not that far away, and I would like to get my problem fixed before then.

Thanks, Brian
PA SHO SHOP

 

[dodgebusta]

Here is my 2 cents worth. All three of the stick shift cars i have ever owned, have always done the same thing.

I would assume that it has something to do with the transmission having to slow down before the syncros will let you into the next gear. Thats how it is on the semi's thats one reason they have a clutch break, to slow everything down. (note: i said thats not the only reason, but its one of the reasons)\

But I would like to see if anybody else has this problem.

 

[illSHOyou]

P.S. My SHO has done this since I put the flywheel and clutch in 2 years ago. No wonder I can't run a 12 second ET!

You might have answered your own question. Seems that you have directly affected the car after the flywheel clutch swap. Whats interesting is that one would think the reduced flywheel weight would increase transmission speed not the opposite.

The clutch could not be completely disengaging. I would check the linkage and make sure your getting full release.

Also, might be benificial to know what fluid is in the transmission. While it would be easy to blame the clutch/flywheel you most likely changed the old fluid during the swap. You could have changed brand? Maybe the fluid is not doing the job, and a change of brand might be nessesary.

Also, before just taken the car all apart, try a different fluid, its only a few bucks to cure a possible simple problem.

What can cause slow shifting:

-Wrong fluid
-Old fluid
-Worn out TOB, With the rpm you turn a ceramic TOB might be a great upgrade
-Broken pressure plate
-Incomplete clutch disengagement, draging clutch
-Internal transmission issues
-Mis aligned clutch

Just some to name a few...

Hope this helps...

 

[AREA 91]

P.S. My SHO has done this since I put the flywheel and clutch in 2 years ago. No wonder I can't run a 12 second ET!

You might have answered your own question. Seems that you have directly affected the car after the flywheel clutch swap. Whats interesting is that one would think the reduced flywheel weight would increase transmission speed not the opposite.

The clutch could not be completely disengaging. I would check the linkage and make sure your getting full release.

Also, might be benificial to know what fluid is in the transmission. While it would be easy to blame the clutch/flywheel you most likely changed the old fluid during the swap. You could have changed brand? Maybe the fluid is not doing the job, and a change of brand might be nessesary.

Also, before just taken the car all apart, try a different fluid, its only a few bucks to cure a possible simple problem.

What can cause slow shifting:

-Wrong fluid
-Old fluid
-Worn out TOB, With the rpm you turn a ceramic TOB might be a great upgrade
-Broken pressure plate
-Incomplete clutch disengagement, draging clutch
-Internal transmission issues
-Mis aligned clutch

Just some to name a few...

Hope this helps...

Here's some more info.
The tranny was rebuilt with all new blocking rings and syncro's 3 years ago.
I have SHO NUT's Ceramic TOB along with the teflon coated fork bushings.
The fluid currently in the tranny is GM syncromesh.

I have tried every fluid under the sun with this combination. Well over a $100 bucks worth.

Red Line MTL
Red Line D4
cheap atf
Mobil 1
Royal Purple
etc.............

 

[Phoenix]

If this can help , I got the Fidanza with the CM1 and it shifts fast at whatever RPM (my redline is at 8k) , tranny runs on royal purple ATF (Max ATF is the name If I recall).

The tranny was never touched before I welded the diff , and it had 200,000 kms.

Far fetched , but if you have a spare tranny and some spare time , I would definatly swap them to pinpoint where its comming from.

 

[Ishodu]

I would suspect the flywheel is flexing and not letting the clutch disengage completely. At low RPM the small amount of friction is not enough to keep the internals under much load. But at a high rpm the slight friction is exerting enough to keep things under a bit of load and cause a shifting issue. Sounds like you need a billet flywheel! As do I as well as a stronger clutch to match.

 

[Sho Amo]

TexanTony used to sell a shim that was supposed to cure this problem.


P.S brian if you fix this and can finally shift fast your going to start breaking even more axles than you already do!

 

[93rev2sev]

I vote transmission.

I suppose it could be the flywheel, but if I had another trans to install I'd try that.

 

[Pro*banshee]

You said that you've been dragging that car for at least two years on that tranny now; it stNds to reason that beating the snot out of it twelve, I mean thirteen seconds at a time doesn't help a tranny do better! When my clutch wasn't fully disengaging I also experienced shifter problems up top too. I remember your hard shifts when I took a ride

 

[AREA 91]

I would suspect the flywheel is flexing and not letting the clutch disengage completely. At low RPM the small amount of friction is not enough to keep the internals under much load. But at a high rpm the slight friction is exerting enough to keep things under a bit of load and cause a shifting issue. Sounds like you need a billet flywheel! As do I as well as a stronger clutch to match.

Update. Flywheel swap to happen berfore the convention!

 

[yamahaSHO]

I too would question the clutch/flywheel operation.

 

[1993MTXSHO]

Update. Flywheel swap to happen berfore the convention!

Feel free to put that light one in my 94 and take my stocker

Also FWIW I have the same issues with my 93 and a stage 2 clutch. I still cannot figure out why it shifts like ****.

 

[Mrhappytuzi]

GM syncromesh? i thought that was a pretty big NO NO to run in the FORD MTX

 

[yamahaSHO]

People on this forum have been using it in SHO's for years. Many swear by it.

 

[rktmn]

Royal Purple Max ATF and 8 oz of GM Limited Slip Differential Lubricant Additive made my transmission shift like butter.

The SHOrt Shifter also makes a huge difference. The shifter limiting bolts will protect the transmission gears and shift fork from the abuse of hard shifting, and give you better control engaging the gears.

The Delrin bushing and the oversize clevis pin takes all the slop out of the shifting linkage and gives better accuracy in lining up the gear gates. If you still have your original worn out linkage clevis pin and rubber bushing in your rod shifter, you are a *********.

I do not have any right now, but I see used SHOrt Shifters for sale every once in a while here on the forum or on ebay.

Today I will be installing a new Clutchmasters organic clutch, with the SHONUT's ceramic TOB. Lets see how that works out.

Once I dialed in my transmission with all the upgrades in my signature, it was a joy to run through the gears in my SHO.

I am looking forward to putting my SHO back together again.

Only reason I am not using the SPEC clutch again is that it lasted 30,000 miles. I hope to get a bit more from the Clutchmasters.

Jose

 

[blownsho94]

I run the Fidanza with a Spec StageII. I love the flywheel and have never encountered any shifting problems. However, I will never buy a Spec clutch again, it just feels weak and slips on occassion after about 26k miles.

-- Kevin

 

[St Louis SHO]

My money is on your car will be faster with a steel flywheel in it.... :wave:

 

[syP]

my old cobalt SS did this after a stage 4 clutch install...


The clutch was too heavy, thus creating too much momentum and needed to slow down..

The same reason i wasnt able to hit low 13s like i should have with my mods.

 

[drivinhard]

brian is your clutch a twin/double spring? I think the only situation where MAYBE you could worry about such would be with a double'd up spring plate. otherwise, I'd run the alum unit, especially for an n/a motor. I always ran an alum unit.

I changed a rear main seal on a 1,100 hp procharged 427 C5 corvette a few weeks ago, and the fella was running a triple disc carbon/carbon Exedy multi plate. I was *amazed* at how streetable it was, it was like driving a stock clutch. All that to say...

I spent some time at SPEC clutch in 'bama last week, shooting some footage of their facility and having them build an 11" alum naughty pressure plate to mate to my alum FW for my NASA time trial Z06. With the alum flywheel, this is my current "low cost" low(er) inertia solution.

However, SPEC cnc machines their own billet mini twin covers and low inertia flywheels and if you've got the dough, after driving that multi plate carbon/carbon unit, that is the *******. I've done/driven/raced a million clutches in a million cars, that's the first no compromise clutch I've ever driven. (Ie, huge holding power, light pedal, zero chatter, stock engagement).

The only compromise is cost, David @ SPEC says a carbon/carbon multi plate will set you back in the ~$2800 range. Since their minitwin covers are more of an "off the shelf type of piece", the flywheel to match it would be the only "application specific" custom machining piece for the SHO, so the cost may not get to much higher than that for a low production run. Might be worth looking into. Otherwise, regardless of who you are buying clutches from, you're always stuck with the cast Valeo bastard size SHO PP and either using higher friction materials (not street friendly) and/or changing fulcrum points on the plate spring which is less than ideal.

If I can make it to NASA nationals next year, I hope to be running one of their carbon/carbon mini twins. Even for the (much larger than the SHO) LS6 application, total weight w/ flywheel/discs/cover, is in the ~14 lb range

 

[AREA 91]

brian is your clutch a twin/double spring? I think the only situation where MAYBE you could worry about such would be with a double'd up spring plate. otherwise, I'd run the alum unit, especially for an n/a motor. I always ran an alum unit.

I changed a rear main seal on a 1,100 hp procharged 427 C5 corvette a few weeks ago, and the fella was running a triple disc carbon/carbon Exedy multi plate. I was *amazed* at how streetable it was, it was like driving a stock clutch. All that to say...

I spent some time at SPEC clutch in 'bama last week, shooting some footage of their facility and having them build an 11" alum naughty pressure plate to mate to my alum FW for my NASA time trial Z06. With the alum flywheel, this is my current "low cost" low(er) inertia solution.

However, SPEC cnc machines their own billet mini twin covers and low inertia flywheels and if you've got the dough, after driving that multi plate carbon/carbon unit, that is the *******. I've done/driven/raced a million clutches in a million cars, that's the first no compromise clutch I've ever driven. (Ie, huge holding power, light pedal, zero chatter, stock engagement).

The only compromise is cost, David @ SPEC says a carbon/carbon multi plate will set you back in the ~$2800 range. Since their minitwin covers are more of an "off the shelf type of piece", the flywheel to match it would be the only "application specific" custom machining piece for the SHO, so the cost may not get to much higher than that for a low production run. Might be worth looking into. Otherwise, regardless of who you are buying clutches from, you're always stuck with the cast Valeo bastard size SHO PP and either using higher friction materials (not street friendly) and/or changing fulcrum points on the plate spring which is less than ideal.

If I can make it to NASA nationals next year, I hope to be running one of their carbon/carbon mini twins. Even for the (much larger than the SHO) LS6 application, total weight w/ flywheel/discs/cover, is in the ~14 lb range

I am currently running a Fidanza 8 Lb aluminum flywheel coupled to a Clutch Master's Stage 3. Ceramic TOB as well.