LGT-700 Manual Transmission - Holy Grail?

[jtwoods4]

For those of you that remember the SS700 transmission and the Kiesler bankruptcy fiasco... all is not lost. It turns out that Legend Gear has all the tooling equipment, is still producing the gear sets, and has made an agreement with 4 suppliers to sell the renamed LGT-700 transmission. (see links below)

Now for a little background.... Everything I have written below is from extensive testing at Road Atlanta with both the TKO 600 Road Race and the Autogear M22X Road Race transmissions using both 3.42 and 3.73 rear end gear ratios.

For years the TKO-600 has been the best thing going for us pro touring guys (in the 5 speed category). As most of you know, the TKO-600 has a terrible 2nd to 3rd ratio drop and the 1st gear is way to deep for most of our cars. In order to perform well in a road race application and shift well at high RPM the TKO-600 also requires about $1000 bucks worth of upgrades. For road racing the TKO 600 flat out sucks. 3rd to 2nd downshifts are not possible/very dangerous due to the huge gap between 2nd and 3rd. In order to downshift from 3rd to 2nd you have to drop the RPM's way down out of the power band in order not to over rev the engine when you engage 2nd gear. I know from experience, broke a rocker arm down shifting from 3rd to 2nd on the back turn at Road Atlanta. Also, If your running a 3.73 rear end, then 1st gear is simply not usable. You would not ever use 1st gear on a track but when we get back to the street we need first gear. The TKO 600 first gear is so deep you have to shift almost immediately after leaving a red light, no room at all for a 3.73 / 3.55 / 3.42 rear (maybe 3.42 but not the best setup).

However, the Autgear Super Case M22X (road race ratios) is an outstanding road race transmission. The ratio drops are perfect from 1st all the way to 4th, perfect for our big torque engines. The transmission is also extremely strong and has taken everything I can throw at it. TKO 600's sometimes blow 3rd gear if your not careful. With the Auto Gear M22X you need to run a 3.42/3.55 gear in order to hit top speed on straight aways without maxing out RPM before you get there. The M22X is only 4 speeds, straight aways need that extra 5th gear. Again, I am speaking from experience at Road Atlanta on the long back straight. The M22X has no overdrive. This means no long road trips unless you have a 3.08 or 3.23 rear gear, but then you cant run well at the track.



Since we have pro touring cars we also want them to perform well on the Street/Highway and a nice overdrive is needed for those long haul events like the Power Tour. The TKO 600 .64 overdrive is great for that, but it is not usable on a road course, simply to much overdrive and no power in 5th gear. The .82 road race TKO-600 solves that problem on the track but loses the deep overdrive for long haul highway driving, not to mention we still have the 2nd to 3rd ratio being to wide.

Well, I think the holy grail still exists and can be found at the link below. The LGT-700 can be purchased with several ratios but one of them stands out as the holy grail. The LGT-700 also comes with the upgrades that have to be done separately and at extra expense to the TKO-600 (like bronze shift pads to make smooth high RPM shifting):

LGT-700 CLOSE RATIO
2.66-1.78-1.30-1.0-.69 OR .80 OD

TKO-600 RR (no no no... this is a bad road race setup)
2.87-1.89-1.28-1.00-.82

1. The LGT-700 Fixes the overly deep 1st gear ratio found on the TKO-600.
2. The LGT-700 Fixes the 2nd to 3rd ratio problem on the TKO-600.
3. The LGT-700 Adds a little more overdrive to help get the RPMS down on cruises but still
provides enough power for road racing

http://legendgt.com/Products/lgt-700/

http://www.sprakerracing.com/


SIDE NOTE
For those of you that are willing to modify your trans tunnel then the REAL holy grail is the T56 used by the Viper Racing team in 1997... I am not including this transmission because it is a 6 speed and I am comparing 5 speeds. It also requires significant modifications to the trans tunnel and will not bolt up to a standard bell housing bolt pattern found on our early model pro touring cars.

Part Number AA08-000-013
Year 1997
Viper Racing
Torqe Rating: 650
2.29 1.61 1.22 1.00 0.85 0.75 (THIS IS ABSOLUTELY PERFECT!)

[mmosley]

Legend Gear was making them for Kiesler, so yes, they have the tooling.

Yes, the ratios in the LGT 700 are better for racing than the TKO 600. The TKO 600 ratios look to be a compromise for cars with tall rear gears and relatively low power.

My T-56 Magnum TUET10009 T56 gear ratios are 2.66-1.78-1.30-1.0-0.8-0.63; this is identical ratios 1-4 to the LGT and gives me 2 OD gears of course.
Perfect really depends on your engine torque curve. Mine is really flat so it is not as critical. Shifting at 6k in first and 5500 in the following gears puts me above 4k on each shift, changing to the Viper ratios would only move it up about 200rpm, it would also mean I have to shift more often. Likewise on the way down, dropping down a gear when you go below 4k would still put you in a safe region. Now all I need are the upshift and downshift lights on my dash.

[andrewb70]

Bowler is also selling LGT-700. The real benefit is that it fits in a GM A-body without the trans tunnel surgery that is normally required for a T56 or a TKO.

Andrew

[Roadrage David]

The close ratio road race version wil come out in 12 to 14 monds!!!!!!...

[andrewb70]

The close ratio road race version wil come out in 12 to 14 monds!!!!!!...

There is no need to have a racing transmission with over drive. Any half serious race car will use a non O.D. transmission because O.D. gears are inherently very weak.

There are already many...many...options for racing transmission that have almost unlimited gear sets available.

Andrew

[jtwoods4]

There is no need to have a racing transmission with over drive. Any half serious race car will use a non O.D. transmission because O.D. gears are inherently very weak.

There are already many...many...options for racing transmission that have almost unlimited gear sets available.

Andrew

Andrew it's not really about having an "overdrive" it's about having a gear that allows you to hit top speed on long straight aways without redlining RPMs and also allows you to have a beefy rear end gear. currently I am not familiar with any 4 speed transmission that will allow you to hit top speed at Road Atlanta, unless of course you had a 3.08 rear end. Actually, Auto gear does make a Muncie gear set with a 0.8 fourth gear. But to be honest with you you really need at least 5 gears for track day events. what transmission would you recommend for track day events and street use in our pro touring cars? Keep in mind that the transmission you select has to work on the track and the street. It cannot be a dedicated race car transmission.

[jtwoods4]

The close ratio road race version wil come out in 12 to 14 monds!!!!!!...

wow that's even better do you know what gear ratios will be in this transmission?

[andrewb70]

Andrew it's not really about having an "overdrive" it's about having a gear that allows you to hit top speed on long straight aways without redlining RPMs and also allows you to have a beefy rear end gear. currently I am not familiar with any 4 speed transmission that will allow you to hit top speed at Road Atlanta, unless of course you had a 3.08 rear end. Actually, Auto gear does make a Muncie gear set with a 0.8 fourth gear. But to be honest with you you really need at least 5 gears for track day events. what transmission would you recommend for track day events and street use in our pro touring cars? Keep in mind that the transmission you select has to work on the track and the street. It cannot be a dedicated race car transmission.

How fast do you really want to go in our old, understandably modified cars? By my calculations, with my tires and gearing, I can hit 150 MPH at 6600RPM in direct drive having 3.42 gears and 26" tires. Seems about right to me...

There is no good answer to your questions because there too many variables. I have a Richmond 6 speed with a 2.77 first gear and 1:1 5th. This makes for a very close ratio transmission. Is it fun at the track, yes. Third and 4th gears are very close and with my relatively broad power curve everything works very nicely together. However, on the street, I often start in 1st, then 3rd, then 5th. All those gears are just not needed for the street, but the .62 O.D. makes for a very nice ride on the highway. I would never shift into O.D. at high speed because I am quite certain that it will break, regardless of the transmission.

Other factors to consider are weight and fitment. The LGT700 supposedly fits into a-body transmission tunnels, which is a huge plus. The T56 Magnum is very robust and has the latest in synchro technology and supposedly shifts like a hot knife through butter, but it is a monster in both size and weight.

The transmission is like any other tool and needs to be selected for the right job.

Andrew

[jtwoods4]

I Drive a Pontiac so I red line around 6000 and I have 373 rear gears but sustaining 6000 rpm for 15 to 20 seconds while on the back straight at Road Atlanta is a little hard on the engine. the red line on our cars means it's ok to bump it every once in awhile but not sustain the rpm at the red line for 20 seconds. sounds like you have a really nice setup in your car the idea of dropping the rear end gear and using the Richmond 5 speed makes perfect sense

[jtwoods4]

I guess the point I am trying to make is that the LGT-700 transmission looks like it's going to be awesome when paired with a 342 to 373 rear end. and it appears to correct lots of the flaws found in the TKO 600.

[andrewb70]

I guess the point I am trying to make is that the LGT-700 transmission looks like it's going to be awesome when paired with a 342 to 373 rear end. and it appears to correct lots of the flaws found in the TKO 600.

Personally, if I had the legendary torque of a Pontiac engine, I would run a 3.42 (maybe even less, depending on tire size) gear and use the 2.66 1st gear transmission of your choice.

Eventually my GTO will get a 400+ ci LS engine and when it does I will use a G-Force dog-ring T56 with the 2.98, 1.99, 1.35, 1.0, .79, .62 gears and drop my rear end to the 3.2x range. Using a numerically low rear gear also has the side benefit of slowing down the driveshaft speed, which is not a trivial concern.

Andrew

[jtwoods4]

yeah you're absolutely right I put a 342 in my 69 GTO and it is absolutely perfect but I made a mistake with the Trans Am and put in a 373 which is just way too much and unusable in first gear.

[andrewb70]

yeah you're absolutely right I put a 342 in my 69 GTO and it is absolutely perfect but I made a mistake with the Trans Am and put in a 373 which is just way too much and unusable in first gear.

So what you're saying is that you don't need an O.D. for track use, you just need a different rear gear. LOL

Or, here is a crazy thought: don't go as fast in the straights. It's not like we are setting any world records here.

Andrew

[jtwoods4]

no that's not what I'm saying because the car still has to have a nice overdrive for long-haul cruises on the highway. so even if I change the rear end I still need an overdrive. the car is not a track only vehicle its a pro touring car that also sees a lot of highway use. a 4 speed transmission could be made to work on the track with a different rear end but you would lose the long haul low rpm highway driving.

[andrewb70]

no that's not what I'm saying because the car still has to have a nice overdrive for long-haul cruises on the highway. so even if I change the rear end I still need an overdrive. the car is not a track only vehicle its a pro touring car that also sees a lot of highway use. a 4 speed transmission could be made to work on the track with a different rear end but you would lose the long haul low rpm highway driving.

Read what I said again.

Andrew

[jtwoods4]

I understand your point and it makes sense. what I'm trying to explain in this thread is that the LGT - 700 transmission appears to be superior in both a track and street application. to really have an excellent performing car on both the track and the street you have to have a 5 speed. the TKO 600 has major shortcomings and it appears that the LGT 700 addresses this.

you are correct the car could be set up with a four-speed to perform excellent on the track but I would lose the street performance that having a five-speed offers.

from my experience and my research the LGT 700 transmission appears to be the holy grail of 5 speeds

no matter what rear end gear you have the TKO 600 first gear is simply too deep and the gap between 2nd and 3rd is too far apart. The LGT-700 fixes this.

[andrewb70]

...

from my experience and my research the LGT 700 transmission appears to be the holy grail of 5 speeds

....

You can't make a blanket statement like that. It really depends on the car, the engine, etc...I have no bones to pick with the LGT 700. In fact, I think it is an excellent option given that it fits so nicely into a-bodies. It's a shame that it is almost $4000 now.

Andrew

[jtwoods4]

again I understand what you're saying so let me rephrase that: for high torque and high horsepower pro touring high performance engines shifting between 6000 and 7000 rpms with a broad torque curve and with 3.31 to 3.73 rear ends the LGT 700 specifications and gear ratios are superior to the TKO 600. also the TKO has to have upgrades done to it in order to perform well at the track. these upgrades cost anywhere from 1000 to 1500 dollars. so once you add in the upgrades that have to be done the price of the lgt 700 is about the same as an upgraded TKO 600.

[andrewb70]

again I understand what you're saying so let me rephrase that: for high torque and high horsepower pro touring high performance engines shifting between 6000 and 7000 rpms with 3.31 to 3.73 rear ends the LGT 700 specifications and gear ratios are superior to the TKO 600. also the TKO has to have upgrades done to it in order to perform well at the track. these upgrades cost anywhere from 1000 to 1500 dollars. so once you add in the upgrades that have to be done the price of the lgt 700 is about the same as an upgraded TKO 600.

Or just do a T56 Magnum... (yes, I know you said 5 speed...LOL)

It's all good man. I am just glad there are options out there now.

Andrew

[jtwoods4]

Yes the T56 would be the ultimate, that's why I included the original side note at the beginning.

SIDE NOTE
For those of you that are willing to modify your trans tunnel then the REAL holy grail is the T56 used by the Viper Racing team in 1997... I am not including this transmission because it is a 6 speed and I am comparing 5 speeds. It also requires significant modifications to the trans tunnel and will not bolt up to a standard bell housing bolt pattern found on our early model pro touring cars.
Part Number AA08-000-013
Year 1997
Viper Racing
Torqe Rating: 650
2.29 1.61 1.22 1.00 0.85 0.75 (THIS IS ABSOLUTELY PERFECT!)