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So GGSX Diff w/ secondary gear WORKS! 88mph in 5th gear @ 3k!!!!!

alansupra94

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I guess my question is now what. /ubbthreads/images/graemlins/rofl.gif I am still very confused on the regards to primary/secondary whole thing. Is the transmission the primary and the secondary is the rear end and front diff?

I guess my question is my best option to just drop in the front diff and use the rear diff? Can I drop the GGSX rear diff into the 4 bolt pumpkin that I have already?

From my calculations (when I say that I mean CheekyChimps excel file), with a 225/45/R18 (26in diameter for the tire) and a 3.1 GGSX ratio, I am looking at 88mph at 3k /ubbthreads/images/graemlins/cool.gif

Thanks,
Alan
 
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cheekychimp

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Quoting alansupra94:
I guess my question is now what. /ubbthreads/images/graemlins/rofl.gif I am still very confused on the regards to primary/secondary whole thing. Is the transmission the primary and the secondary is the rear end and front diff?

I guess my question is my best option to just drop in the front diff and use the rear diff? Can I drop the GGSX rear diff into the 4 bolt pumpkin that I have already?

From my calculations (when I say that I mean CheekyChimps excel file), with a 225/45/R18 (26in diameter for the tire) and a 3.1 GGSX ratio, I am looking at 88mph at 3k /ubbthreads/images/graemlins/cool.gif

Thanks,
Alan



Make it simple on yourself basically you just want to "effectively" put your GVR4 1st-5th gear into your GGSX gearbox. Now without knowing anything about the GGSX really I don't know if it makes sense to actually use the GGSX transmission case but you get the idea. But yes to answer your question you need to use both the front and rear GGSX differentials. The rear diff should drop into the 4 bolt pumpkin but you will not be able to use a plate LSD only the GGSX rear diff (I am not sure if that is open or viscous) because the rear ring gear won't fit over the larger LSD body. I know this because I purchased a rear ring and pinion from a GGSX years ago intending to build exactly this gear box but the gear wouldn't fit over the ATS Carbon clutchpack diff according to Alex (Bimmubishi). I ended up having to use a standard 3.545 rear ring and pinion gear and the corresponding gears from a USDM spec VR4 transmission at the front.
 

alansupra94

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^^^^^^

Well me and GSXCONVERT have been looking at things and it seems to make sense just to use the whole entire GGSX transmission with a 1G first gear (since that is the weak point). I guess the biggest difference is that the GGSX transmission uses a FWD flywheel and clutch setup but that will not be hard to find.

I was thinking about just swapping all the gears from my VR4 into the GGSX but I don't really see the point considering they are exactly the same on the inside besides a small change in 5th gear. Reason for this was since the GGSX and VR4 were both build in Japan, they both received VERY similar transmissions.

click

Also GSXCONVERT can rebuild transmissions so he is going to run through the transmission and replace anything that is fubared so essentially I will have a rebuilt transmission like I have now. Just have to get a FWD flywheel and clutch now. /ubbthreads/images/graemlins/grin.gif

Quoting GSXCONVERT:
88 mph? careful you'll end up in 1885 at that speed.....



/ubbthreads/images/graemlins/rofl.gif
 

alansupra94

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Now that I think about it, I could in theory just slap the rear end on and drop the diff in the front and achieve the same effect correct?

That might be a better option.....
 

alansupra94

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Now I found another problem.

According to here:
click


1st 2.846
2nd 1.684
3rd 1.115
4th 0.833
5th 0.690
Rev 3.166


Primary 1.68
Secondary 3.1

Transfer 1.09
Rear end 2.844

Final 5.208

So it looks like Primary is kind of higher. That seems to make sense now. I basically need to drop the front and rear diff from a GGSX AND use the VR4 transmission in order to use their primary.
 
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cheekychimp

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Yeah you are right!

Sorry that's my stupid fault for saying put the VR4 gears into the GGSX transmission, I completely forgot about the different primary on the NA setup. You do need the 1.275 primary.
 

alansupra94

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So would I be able to just get the GGSX front diff and drop it in? That seems like a better option in my eyes since my transmission is already rebuilt with new sychros and all that jazz.

Also Cheeky did you send me the ratios? or was it someone else? I think it was you. I noticed that your excel sheet "gears" doesn't match "max speed" sheet with the same values. I checked online and it seems that "max speed" isn't calculating something right or something.
 
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alansupra94

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After talking to Shep, I don't think this might be plausible. Right now I sent Shep an email but they seem very skeptical on the phone.

I have learned that it is very easy to play with numbers and get something you want. However, PHYSICALLY, making it work is a totally new story. The rear end seems to be a cake walk but the front is going to be a nightmare as it seems that the "diff" isn't the problem. The final drive ratio is the problem. And because I am changing this to a number that hasn't been seen before, I might be screwed since I would need a matching final drive ratio.

Not sure if I am seeing this right but maybe a transmission expert can chime in.
 

cheekychimp

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I'm not sure how either Excel File calculates the max speed at a given rpm. They are slightly different. Whichever way you look at it, this is still the best combination of parts to net you a better cruise rpm without going to an EVO III gearset.
 

alansupra94

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Quote:

The "Primary" ratio is the Intermediate Shaft driving the Center Diff on an AWD or the Output Shaft on a FWD.

The "Secondary" ratio is the Output Shaft driving the Ring Gear on the Front Diff - the actual ratio of the axle shaft rotations compared to the tranny internals.

Primary x Secondary = final - this affects the rpm of the engine vs the rpm of the front axles.

Secondary/Transfer = Rear diff
The two must equal each other for an AWD car to roll without burning up the center diff (which is why you shouldn't run tires with different diameters F/R on an AWD).

If someone wanted to change the final drive ratio on an AWD, you need to change the ring gear on the front diff along with the stubby Front Output Shaft that is driven by the center diff. These are both inside the transmission. Then the rear differential ring and pinion gears must be changed to match. The rear diff ratio will be slightly different but will equal out when multiplied by the 1.090 of the transfer case. IF the Galant GSX gears will fit in an AWD TEL, they would probably work pretty well for a high powered AWD drag racer - you'd have to launch at a slightly higher rpm, but each gear would give a higher mph than before, so you could leave it in each gear longer. Top speed could be over 200mph using GGSX gears in a TEL AWD with enough power to spin at 8K (using a TMO ECU to allow the higher limit).




Looks like I was right. I guess in order for me to use this I will need a custom ring gear and a stubby front output shaft.
 

cheekychimp

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Alan, I am not reading it like that, I don't see anything wrong with the figures. Are you assuming that the 'final ratio' and 'rear diff ratio' have to be equal? They never will be and don't even match each other in the stock VR4 and GGSX transmissions. It is the transfer case ratio that matches them.

My understanding of this is that if you intend to use the GGSX rear end you MUST use the GGSX secondary ratio and the appropriate transfer case ratio. This isn't immediately obvious here because every configuration uses a 1.09 transfer case ratio. If however we included an Evolution III gearbox in here you would see the transfer case ratio in that application is actually different.

So to recap if you use the correct GGSX transfer case ratio, the GGSX rear end and the GGSX secondary, you will be fine. You can then simply alter your final drive ratio by choosing the appropriate primary ratio, which in your case is the VR4 primary.

VR4 primary;
GGSX secondary;
Either transfer case (since they are both identical in ratio); and
GGSX Rear End

Your final ratio will be 3.953 which is why you get the extra speed i.e. it is geared higher than both the VR4 final ratio (4.929) and the GGSX final ratio (5.208).

Anyone else want to confirm the math?
 

alansupra94

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I was under the impression that the final drive ratio is a gear with in the gear box. Am I seeing that correctly?

Now I am VERY confused lol.
 

cheekychimp

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No the final drive ratio is the combined ratio output of the primary ratio and the secondary ratio.
 

alansupra94

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Oh so then...yeah it should work then.

Now the problem lies with which transmission case do I use? Do I use the GGSX transmission and drop the VR4 gears into it or do I use the VR4 transmission and drop the GGSX gears into it?

Thanks,
Alan
 

alansupra94

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Cross my fingers! GSXCONVERT is going to test out the GGSX Secondary (output shaft, ring pinion and diff) in his 1G transmission to see if it will work!

Also apparently you can drop the GGSX rear end right into a 4 bolt. I will have to look to make 100% but looks legit for me.
 

Struc

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Quoting alansupra94:
I guess the biggest difference is that the GGSX transmission uses a FWD flywheel and clutch setup but that will not be hard to find.



Keep in mind the pressure plate & clutch disc are more than likely the same. It'll only the the flywheel that is different, although I would have thought it would be the same. Be sure to do some measurements. If it does need a FWD Flywheel, then your starter will probably be different too.

Watching this thread very closely. Can't wait to see what your impressions are once the transformation is complete. I would love to get my RPM's down at highway speeds too, but don't think I'd go quite to this extreme. /ubbthreads/images/graemlins/grin.gif I would love to get a EVO3 5th gear. Actually, I'd love to find an old TRE 18% taller 5th gear.
 

alansupra94

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UPDATE: f*** YEAH IT WORKS!

Just confirmed with GSXCONVERT that the transmission works! The GGSX diff + secondary gear fit perfectly 1G transmission (aka it will fit in a VR4). This is going to be freaking sick! I really didn't think my idea would actually go from a conceptual to physical so quickly.

Just so everyone knows, this mean my cruise speed in 5th at 3000rpm would be 88mph. /ubbthreads/images/graemlins/rofl.gif This is going to be a one of a kind galant now! If I can get that VGT working, which I think I could in theory do, I will be the king.

Props to GSXCONVERT for having philosophical conversations about this!
 

cheekychimp

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If you want an idea on the spread of ratios go to Magnus' site and look up the ratios of their Dogmission. When I looked this up years ago the ratios matched almost perfectly so it is actually a decent setup for drag racing too, just be aware that it most likely won't take the abuse of a dog box. Props for the real inspiration behind this Alan really goes to John Teeter a real old hand on here who doesn't post much anymore. He put me onto this years ago. I was in the process of doing this conversion for my Galant when we discovered the rear GGSX ring and pinion doesn't work with an ATS carbon LSD. The LSD is bigger as it was designed for a 3.545 or 3.909 rear diff ratio ring and pinion gear. So I had to abandon this setup and go with a standard 3.545 secondary, but using a mix of EVO III and RS GVR4 (Evolution) 1st to 4th gears and the custom TRE 5th gear. I still get a very low rpm for cruising in 5th it is just a different way of doing it.
 

alansupra94

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Are you referring to the diff or the gears? The primary gears will be my VR4 gears, so if I really wanted too, I can grab a built transmission primary too and drop it in. As for the diff, I guess I can't really do much about that. I don't plan on really doing hard launches or banging through the gears.
 
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