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Discussion Starter · #1 ·
I have just completed 2 8 hours of endurance racing with my K swap EG with the 6 speed transmission and it seem like the I'm having issues with the syncros for 2nd and 3rd gear. Can anyone give me some suggestion or recommendations to make the 6 speed stronger and more reliable for endurance racing without going to sequential or doing dogbox and such? Reliability is the key on the rebuild for the next race.
 

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are you on a clutch diff or a gear diff? how fresh was the transmission? are you only using gears 1 through 5 or do you have FD aggressive enough to use 6th?
 

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Discussion Starter · #3 ·
are you on a clutch diff or a gear diff? how fresh was the transmission? are you only using gears 1 through 5 or do you have FD aggressive enough to use 6th?
The LSD I have is the MFactory Helical LSD + stage 1 race pack. It was rebuild but didn't change the syncros. The track I was at is Watkins Glen and it is a high speed track. I did us 6th gear on the back straight and perhaps got up to close to 135MPH at about 5000 rpm. I'm looking for a stronger gearbox. Are the 5 speed gear box stronger than the 6 speed?
 

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1. make sure you arent using a trans fluid with a friction modifier... you dont need it with a helical lsd... if you are using one with them the friction modifier will speed up synchro wear.

2. get a carbon synchro set.

3. when you are ready... you need to have your gears and synchros (new) cryo treated and have your gears low friction coated. K series transmissions suffer from heat related issues.... to include synchro issues. unlike B series cars, you cant overfill the trans to help so you have to go to more expensive routes to help with heat.

4. if you are really bonkers (i think most endurance racers are)... you can look into a trans cooler and/or get the case treated with a heat dissipation coating.
 
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Discussion Starter · #5 ·
1. make sure you arent using a trans fluid with a friction modifier... you dont need it with a helical lsd... if you are using one with them the friction modifier will speed up synchro wear.

2. get a carbon synchro set.

3. when you are ready... you need to have your gears and synchros (new) cryo treated and have your gears low friction coated. K series transmissions suffer from heat related issues.... to include synchro issues. unlike B series cars, you cant overfill the trans to help so you have to go to more expensive routes to help with heat.

4. if you are really bonkers (i think most endurance racers are)... you can look into a trans cooler and/or get the case treated with a heat dissipation coating.
Hi, Thank you for the reply. I will be ordering the synchro set for a rebuild and I will be adding a trans cooler with Tilton pump as most people said heat is one of the biggest issue with these transmissions for endurance racing.

Currently, I'm using Torco MTF as that's what MFactory is recommending instead of RTF. I was thinking of switching over to Motul Gear 300 75w-90. I think these 2 options are safe and performs well in race condition?
 

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cooling, lightweight clutch and FW will help. you might consider switching to a 7.25 or small single disk clutch. The friction disk should feature damping springs.
 

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Hi, Thank you for the reply. I will be ordering the synchro set for a rebuild and I will be adding a trans cooler with Tilton pump as most people said heat is one of the biggest issue with these transmissions for endurance racing.

Currently, I'm using Torco MTF as that's what MFactory is recommending instead of RTF. I was thinking of switching over to Motul Gear 300 75w-90. I think these 2 options are safe and performs well in race condition?
MTF doesnt have friction modifier... BUT it doesnt hold up to heat. Most sprint racers run 50/50 RTF and MTF to try to help with the heat and keep costs down. i generally run very aggressive transmission setups and have to run all Motul or RTF... and with my plate diff (Mfactory in my B series and OSG in my K series) after about 3 sprint events they start to smell like they are cooking.

RTF will have a friction modifier and some of the Motul gear oil will be marked with a friction modifier for plate lsds... so be careful.
 

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Knock on wood, we are running an OEM junk yard take out PNN4 6-speed out of a 2006 Civic Si in our EG hatch endurance car. We have ~8 full race weekends on the transmission. I opened it to check and measure synchro wear before using, but did not replace any parts. We run Redline MTL and have not had any issues. Coupled to our stock K24a2 we are consistently using only 4th, 5th, and 6th gears. No cooler or any plans to add one. Blackstone oil lab analysis shows no appreciable oil break down or transmission wear after 16+ race hours.
 
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