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FD Factory 5 Speed - High RPM shifting advise

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FD Factory 5 Speed - High RPM shifting advise

Old 06-21-10, 02:06 AM
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FD Factory 5 Speed - High RPM shifting advise

Hi all,

Long story short. My FD circuit car is getting really anoying when shifting at high RPM. It quite often goes into 5th instead of 3rd and is getting harder and harder to change at high RPM.

I have a spare box and was thinking of giving it new bearings and syncros, but was wondering what experiences others have had with the factory box. Is there any point persisting with it and just changing syncos all the time? or should I just save for a dog box?
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Old 06-21-10, 10:52 AM
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if you can't train the driver to find the right gear, you should save for a dogbox...

one of the things you could try is a LONGER shifter, it'll increase the distance between 3rd and 5th, and hopefully make it easier to find.
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Old 06-21-10, 11:19 AM
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I've had issues shifting around 8100rpm, I think I'm going drop the shift point to 7500rpm and slow the shift down a bit...I wish I had a dogbox.
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Old 06-21-10, 11:20 AM
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Bob Bondurant's book on high performance driving helped me out a lot with this. Pick it up if you can, but I'll try to run through the basics real quick here.

1. Do not "grab" the shifter when shifting.
2. When moving the shifter toward the back of the car, just rest your fingers on the forward part of the **** and gently pull the lever back. Do not attempt to guid the shifter, just let it go where it wants to (it will find the right spot as long as you are not trying to force it somewhere else).
3. When moving the shifter forward, just push it gently forward with the heel of your hand. Again, let it go where it wants to, and it will find the right place.

The key thing to remember is that the shifter will always go to the correct location as long as the driver is not forcing it to go somewhere else. By not grabbing onto the shifter when making changes, you can make things a lot easier. The gates are dependant on rpms, which is now the shifter "knows" where you want to go.




.
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Old 06-21-10, 04:48 PM
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Thats for the replys, but the "getting 5th instead of 3rd" is just an off shoot of the real problem.

The real problem is it not wanting to mesh and change well. Its graunching in every gear change at high revs when its hot - is perfect when driving on the road. (going from 4th down to 3rd 3 times and it not wanting to go in, eventully getting into 5th is whats happening, but again, changing from 2 through the gears to 5th is more of a problem)

What Im wanting to know is: is there any point in my replacing syncros, or is this just a problem Im going to have to live with if using the FD box?
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Old 06-21-10, 05:20 PM
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CA

It's a little unclear what you're asking, but if it's grinding, you may just need to replace the synchros. I had mine rebuilt in '08. It's nice to not have any grinds.

But the mis-shifting isn't related to the synchros.

You haven't mentioned whether or not you're using the stock engine mounts, which are very soft. When I bought new ones last year, I could push the engine with my pinkie finger. Now I'm using the Banzai mounts, although you may want to section out a piece of the mount as the engine may sit a little higher than the stock mounts. (I need the engine about 38mm lower to fit under my Cusco D brace.) You may also consider using/fabricating an engine torque brace to keep the engine from rotating the engine/transmission.
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Old 06-21-10, 07:35 PM
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yeah Im bassicly just asking if a freshly rebuilt FD box with new syncros is ok with the abuse of track racing or if its just flat out a wast of time rebuilding it.

Im a fan of doing things once and right and dont want to go to the hassle of putting new syncros throughout if its still gonna be graunchy as with high RPM changes. Keep in mind the car is making about 4-450whp on the track.

Disregard the mis-shifting problem for now. Half of this will be the short shifter thats going in the bin. (only reason I mentioned it, is it was never a problem untill it got this tied and started graunching in every gear. It used to slot into 3rd on down changes fine)
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Old 06-21-10, 08:53 PM
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Originally Posted by TURSTY View Post
yeah Im bassicly just asking if a freshly rebuilt FD box with new syncros is ok with the abuse of track racing or if its just flat out a wast of time rebuilding it.

Im a fan of doing things once and right and dont want to go to the hassle of putting new syncros throughout if its still gonna be graunchy as with high RPM changes.
I am not sure how the FC box compares to the FD box, but after throwing money at FC boxes with many different and knowledgeable shops, I finally said enough is enough and went dog box... and I don't make nearly the HP you do. I could have bought two dog boxes had I not thrown money at the stock box.

You already said you are a fan of doing things once and doing it right so you know the answer. Spend now and skip the aggravation.
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Old 06-22-10, 05:19 PM
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My $0.02, the stock boxes are a waste of time. At the 400 rwhp level with slicks we've launched 3rd gear in 2 stock boxes. 1 FC in an FC and 1 FD in an FD, Both boxes broke right as we were putting full boost down in 3rd gear. The gears simply came apart. I went with the G-force T5 dogbox and beyond having way better gear rations it shifts faster, consistent and lets more power through. Stock transmissions were not meant for racing and they will not stand up to the abuse that racing delivers. I for one can't calmly do a gentle push into the next gear as a Porsche GT3 is right behind me going onto a long straight. The dog box can take it when you get a little over-excited. Stock boxes you start missing gears, etc.
If I had it all to do over again I'd likely just get a Jerico. I've heard nothing but outstanding stories of people abusing them horribly (like no gear oil) and rebuilding them inexpensively.

-Trent
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