Changing Gear Sets [Merged 11-7] transmission drive ratios

[gsx951]

I have only used the GVR-4 first but like that a lot for street use.
The OE gear is too short. You have a substantial increase in torque; you'll be on the gas longer before the shift to 2nd.

 

[jtmcinder]

I have only used the GVR-4 first but like that a lot for street use.
The OE gear is too short. You have a substantial increase in torque; you'll be on the gas longer before the shift to 2nd.

Technically, a taller first means less torque at the wheels.

- Jtoby

 

[silvah_gsx]

Does TRE's price include install, or is that just for the gear itself?

Also, is it true that a taller gear reduce stress on the tranny?
In F1 they can't go too low on the 1st gear because it'll break the tranny, so at tracks like Monaco they'll use a short first gear for qualifying and for about 20 laps total in the race.

 

[Burnett03]

Who told you it was stronger? I've always heard it was weaker.

 

[project_tsi]

Who told you it was stronger? I've always heard it was weaker.

The Galant VR4 gear is weaker, and 7% taller.

This gear is the "JDM" 11% taller and stronger than OEM gear.

 

[marcmsj]

I'm thinking this gear would be better for people with traction problems. Might actually help some people get a better 60 ft time.

 

[gsx951]

Technically, a taller first means less torque at the wheels.

- Jtoby

Perhaps I was unclear. Paul has a substantial increase in torque (due to mods).
This will allow for him to launch in a taller gear and then stay in that gear longer.

 

[jtmcinder]

I've heard that argument before and was using it, myself, to talk myself into it being a win/win. But then I noticed that Shep has a stock first and I can't imagine that his car is lacking in power. The other factor that we might be ignoring is spool. A short first not only provides more torque, but also might allow the turbo to spool up faster. So, if you aren't near full boost at the line, the shorter first might be better for this reason, too.

- Jtoby

 

[gsx951]

Two points here regarding John:
1) He does not run a DSM transmission. I'm not aware of what ratio he's using but it is a dog box.
2) He runs in excess of 10,000 rpm.

 

[99gst_racer]

Who told you it was stronger? I've always heard it was weaker.

Jon Ripple told me it was stronger. If you compare the 11% gear to an OE gear side by side, you'll see why.

You typically want as much material behind the gear as you can get. If you measure from the peak of the gear tooth to the all the way down to the inside of the ridge (the red area), you typically want that same amount of material (or more) behind the gear teeth (the green area). The 11% taller gear has more material in the green area than the OE gear and/or the Galant gear. This is where the added strength comes from.

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NOTE: This is not an actual image of a DSM gear. It is only used for reference.


This also explains why our 4th gear is so weak. PIC

 

[AHALLA05]

gsx951 1. John actually does run a dsm transmission in his car, it just has straight cut gears. Which is what im guessing you were referring to. Either way he still broke 8`s with an upgraded OEM gearbox with OEM gears.
2. Yea if you watch his vids you can see when he missed a shift the tach completely pasted 13,000 .

Any how, im not sure which 1st gear TRE offers but thier is a couple different 1st`s. The GVR4 is the most common used to upgrade. Unfortunately I has to be the most commonly broken. Next is the JDM or to many, the Evo 2 & 3 1st gears. I`m not completely sure which is which or even if it is an evo 2 but i`ve seen the evo 3 1st and it is deffinately the tallest. The thing is, is that the ring and pinion of these("JDM") gearsets bring the overall ratio of 1st down to a shorter than U.S. ratio. This gear is not made to be put into the U.S. gear box. It is so tall that the torque of motor just rips the teeth off of the gear on hard launches. It is better for a turbo car because it allows the car to stay into boost longer in the gear, which is always a plus for our cars. The gear provides a weak spot on the awd more than Fwd cars. Under high HP awd`s with sticky tires it is easyer to rip the tooth of the gear than to spin all 4 tires especially under a hard launch. On Fwd cars it would most likely be easyer for the trans to send the power out to the wheels and spin than to break the teeth on the gear.This gear would be a big plus for fwd cars trying to prevent premature wheelspin out of the hole due to the lag of the gear being so tall. But like I said the gear is not ment to go into the trans and after several hard launches the gear may fatigue and break which causes a major problem for you considering you have a 2g fwd (cases are extremely hard to find and expensive. Also the damage those broken teeth can do to the rest of your build trans(assuming you have one)
99gst_racer: with your diagram. Say the green part is 5 inches. It can only do so much because the teeth only grab so much of that gear. The GVR4 gear already has about 1" of material in that green area while the OEM has a very small amount less. I dont believe that this amount is enough to affect the strength of the gear.
Hope this helps

 

[housegsx]

When I had TRE rebuild my transmission I went for the taller 1st gear. It's barely noticeably taller. Maybe a little more friendly driving slow like in traffic. It's also supposed to be easier on 2nd gear synchros because they are closer to each other and that also helps keep turbo spool up into 2nd. I like it.

 

[99gst_racer]

99gst_racer: with your diagram. Say the green part is 5 inches. It can only do so much because the teeth only grab so much of that gear. The GVR4 gear already has about 1" of material in that green area while the OEM has a very small amount less. I dont believe that this amount is enough to affect the strength of the gear.
Hope this helps

Regarding to your comment about the GVR4 gear, are you sure you are measuring the green area, or the blue area (pic below). I have never seen a GVR4 first gear before, so I cannot comment. Though, I was under the impression that it was quite thin behind those gear teeth.

The material on the inside of the gear teeth does not make the gear "invincible", but it does make a real world difference. Take 4th gear for example. The "green area" material is only half as thick as the height of the teeth. This was because the gear was cut to accept a bearing. The cut extends 3mm into the side of the gear, and the total width of the gear is only 14mm. If you were to pull a gear from a tranny with 100K on the clock, you can literally see wearing differences on the teeth themselves between the first 3 mm and the last 11mm. This is directly due to the fact that there is a thin "green area" right behind the teeth. The first 3mm of the gear teeth are virtually worthless due to design.

There are other qualities that add/deduct the strength and structural integrity of a gear, but when directly comparing DSM 1st gear options, the meat behind the teeth is the most notable difference.

 

[99gst_racer]

When I had TRE rebuild my transmission I went for the taller 1st gear. It's barely noticeably taller. Maybe a little more friendly driving slow like in traffic. It's also supposed to be easier on 2nd gear synchros because they are closer to each other and that also helps keep turbo spool up into 2nd. I like it.

Thank you for sharing your opinion, Erik.

Would you, any by chance, happen to have a before and after 60-foot track times?

 

[housegsx]

Unfortunately I do not. I still have the t-25 so I don't bother with drag. That'll all change in the next month or so though.

 

[AHALLA05]

"The "green area" material is only half as thick as the height of the teeth. This was because the gear was cut to accept a bearing. The cut extends 3mm into the side of the gear, and the total width of the gear is only 14mm. If you were to pull a gear from a tranny with 100K on the clock, you can literally see wearing differences on the teeth themselves between the first 3 mm and the last 11mm. This is directly due to the fact that there is a thin "green area" right behind the teeth. The first 3mm of the gear teeth are virtually worthless due to design. "

I`m sorry but I dont understand what your trying to say here. Ive included a picture of a gvr4 1st gear that had laying around. Ill try to get you a picture of a 2g fwd 1st here in a couple of days if it helps. Ive never really tried to compare that "green area" u talk about, but from the problems people have had with the gvr4 I dont know if its worth the money and the consequences if it breaks. Im deffinately willing to try and help you come to a conclusion so if you have any ?`s or need any certain pics just let me no. A.J.

 

[99gst_racer]

Wow. Now I know why that gear is so weak. There's not much support for the gear teeth. I wish I had a picture of the 11% taller gear to post up for comparison....

 

[AHALLA05]

Ok, first off I might as well give you the bad news. I dont know what I was thinking before, but you have a FWD. All of these gears are only offered for the AWD dsms and galant`s or evo`s. So even if you wanted a taller first gear in your gst you wouldnt be able to. About the evo gears though. I found the two different evo 1st`s and compared them to the dsm and GVR4. The galant deffinately lacked some of your "Green" area of metal but only like an 1/16- 1/8 of an inch. The two evo gears were comparable to the dsm material wise, but way taller of a gear. The order went from the O.E gear being the shortest geared but biggest gear size wise then the galant. Next were the evo`s, I am unsure of which is which but the size difference is noticeable. I had my buddy take some pics on his cell but they are not comming through my email so ill try and take some here in the next couple of days.

 

[JOEY A]

Shep runs a 4speed trans now, so there is nothing stock about it...and his setup has changed many times

 

[JOEY A]

Ok, first off I might as well give you the bad news. I dont know what I was thinking before, but you have a FWD. All of these gears are only offered for the AWD dsms and galant`s or evo`s. So even if you wanted a taller first gear in your gst you wouldnt be able to. About the evo gears though. I found the two different evo 1st`s and compared them to the dsm and GVR4. The galant deffinately lacked some of your "Green" area of metal but only like an 1/16- 1/8 of an inch. The two evo gears were comparable to the dsm material wise, but way taller of a gear. The order went from the O.E gear being the shortest geared but biggest gear size wise then the galant. Next were the evo`s, I am unsure of which is which but the size difference is noticeable. I had my buddy take some pics on his cell but they are not comming through my email so ill try and take some here in the next couple of days.

Cant you weld the center diff in a awd trans and then put it in a fwd car...?

 

[BrokenTsi]

He did an AWD conversion on his gst.

I have a TRE transmission with a stock 1st gear. My 1-2 shift sees 9400rpms and I cut 1.72's on ugly cheap junkyard tires. I dont see a need to change it.

 

[99gst_racer]

Ok, first off I might as well give you the bad news. I dont know what I was thinking before, but you have a FWD. All of these gears are only offered for the AWD dsms and galant`s or evo`s.

As BrokenTsi pointed out above, I recently completed an AWD conversion on my GST. And my fresh TRE rebuild now has this 11% taller 1st gear. I just haven't had a chance to play with it yet.

Since I started this thread, I have driven Project_tsi's 1G (which also has the 11% taller gear), and I loved it. It seemed to be a great modification for a car that still see alot of street time.

 

[nightspeed87]

Cant you weld the center diff in a awd trans and then put it in a fwd car...?

Bucci did this right?

 

[olmytsi]

I have the video of Devo tuning's evo 2 or 3 from Illinois going 8s in the quarter mile with a first gear that went all the way to 60 or 70 and it definitley looked like the tall first gear made a huge difference in getting out of the hole. I remember talking to Yusuf who has an evo 2 or 3 and is friends with Adam from Devo tuning but i forgot where he said that gear came from.

 

[BrokenTsi]

hmmm. Let me know how you like it, because I'm looking at getting rid of my TRE trans to get another one built. I might like a taller first gear.