Hi everyone, I have been looking around and I think I have found most of the information I need but I still want to make sure before spending too much money in something that could be wrong.
I have a '93 FD, it is extensively modified but still a daily driver and I am about to buy a G-Force T5 transmission for it. The question is: Helical Dog Ring or Synchronized?
I do want the helical dog ring since I know it is better for faster shifting and gears 2 to 4 you can shift without the clutch. It is also stronger. But it has the downside of being a little harder to shift at low speeds AND a little noisier.
Now, the question is: Is it just a little noisier than the synchronized one or MUCH louder? Because I know the Straight Cut Dog Ring is the really loud one and the straight cut is what makes most of the noise. I dont mind some noise since I already have a bridge port with 4" exhaust so the car is pretty loud, but the constant whining noise of the straight cut for example would be too much.
Are there also any other reason against the Helical Dog Ring in a street car?
Thanks in advance for any insights into the subject.
Leo

 

It is NOISY! Not as noisy as a straight, but would get pretty annoying on the highway!
As well you have always shift hard. So that could get annoying as the shifting window is small. I would stick to the Synchro version if I was you!

 

Thanks for hte answer abeomid. Do yo have a helical dog ring transmission or have you ridden in a car that has one?
Leo

 

Nobody else has any other opinions about it?

 

PM SpeedNyc, i believe he has a gforce, street driven. It might be a T56, i cant remember atm late night. PM him anyhow.

 

This might be helpful......



Doesn't sound noisy to me.....


....Compared to this

 

Thanks, yes I saw those videos before and according to what I can get from them, the helical dog ring is much smoother than the straight cut. And it is pretty streetable as the Pfitzner video shows.
BUT I have not been able to find a video of a Helical Dog Ring from G-Force, I guess it would be the same but just want to make sure since the Pfitzner is a higher quality, higher price gearbox.
Leo

 

I would go with a synchronized 1st and 5th, dog ring the rest. It will keep things civil on the streetlight. As for the helical vs straight cut I would use straight cut, it removes the thrust forces from the main bearings and most I have seen have thicker gears. In the long run it will last longer.

 

Yes, the G-Force has synchronized 1st and 5th as far as I know. Thanks for the comments.
Leo

 

Wow! nobody else that has any experience with this kind of transmission?
At least I had a response from SPEED_NYC and he told me what I thought so far, it is clunky or noisy when engaging the gears but not while driving. So it should be ok to drive in the streets as far as I don't expect a silent gear engagement. That is much better that the constant whining of the Straight cut gears
Leo

 

I know I'm kinda late to the party on this one but I have driven a 3-rotor FD with a stock 'box modified with the first 3 gears switched to dog rings and it was awful. I was under the impression that I knew how to match revs (got quite good at it in autocrossing) but it's worlds different. I had the car for a couple days, tried shifting without the clutch, and double-clutching; I'm careful with my equipment and would fear that by the time I got smooth enough that a passenger wouldn't get seasick, the trans would need a rebuild. Any time you grind a gear or miss a shift, you're knocking mostly small, but sometimes big pieces of metal off. Just keep that in mind before you drop that kind of money into this.

 

Thanks for the reply zak_rabbit, I didnt buy the tranny yet so I will consider your input.
Leo

 

In my experience, problem is with people who go from synchro transmissions to dog ring transmissions tend to be not aggressive enough when shifting. You need to pull the shifter as fast as you can or it will grind which is the complete opposite of a synchro transmission. Blipping is more important than rev matching. When you rev match, you aren't unloading the input shaft which is required to reliably and safety shift a dog box. It will grind and make uncomfortable noises if this isn't done.

Take everything you thought you knew or were good at on synchro transmissions and toss it out the window and start fresh!

I think a dog box on the street would be fine as I would consider it to be similar to a cool down lap at the track. Just takes practice to gain finesse for low rev shifting.

 

I have the liberty gear face platting for my RX4 and it works fine. Had it for over 2 years while street driving and no problems. Trans is a turbo II.

 

If this how you really feel, don't do it. I've driven a dog ring straight cut box on the track and like mentioned earlier the cool down lap would be like driving on the street and it would suck to have to do that every day and like you said the whining of the straight cut isn't really heard because of the exhaust noise but every time you shift the giant clunk you get is impressive. as mentioned earlier by someone else "by the time I got smooth enough that a passenger wouldn't get seasick, the trans would need a rebuild" that big clunk every time you shift wether it be all gears or just 1st and 5th will get annoying, plus what are you really gaining? there's a guzillian cars on this forum that make huge power and don't have dog boxes. dog boxes were always meant to be used on the track, that's why you posted in the race car tech section. think about driving said box for a year............... yeah that is an annoying thought

just my .02 worth, don't spend it all in one place.

BigAl...

 

Did they face plate all gears or only 3, 4, and 5?

 

Clunks into, 1st, 2nd, 3rd, and 4th. 5th is the reg synchro...it takes some getting used to but you just gotta shift quick that's all. Hell, even my wife drives it just fine