7th or 8th gen rear diff?

[belize1334]

I'm working on getting my car to be ESP legal for autocross. One of the constraints is that the rear-differential cannot be externally modified in any way and must originate from a galant (any galant). So, I can either swap a 4-bolt LSD into my 3-bolt housing...or I can put a rear diff from a 7th or 8th gen galant in there as per the update/backdate allowances.

So, does anybody know if there is a desirable rear diff from one of the later gen galants that will swap in directly w/o modifications? I know it's a long shot but it's worth asking.

 

[Lonewolf64]

Maybe you'd like to contact either Shep or Jon Ripple (TRE) and talk to them about having them retrofit an Evo 3 mechanical diff into your 3bolt housing. Both of them offer this service. You could also check to see if Jack's offers this service as well.

 

[belize1334]

^^ I agree that those options would work well but I think that they're out of my budget range. I'm looking for something more along the lines of a 4-bolt swap equivalent from a 7th or 8th gen Galant. If, for instance, the 7th gen Galant used the same 4-bolt LSD as the 2gb DSM, then I could just use the 4-bolt that I already have and be perfectly w/in the rules. So, does anybody know anything about the rear diffs in later model Galants?

 

[grocery_getter]

Just swap in a 4 bolt LSD from a late 1G into your 3 bolt pumpkin housing complete with the 4ws drive port. That way there is nothing externally different look wise from your factory 3 bolt diff housing with the 4ws drive port. I've done this job twice! Easy and cheapest option! I can't imagine that being harder than to fabricate subframe adapter mounts to mount a completely different diff housing in the back.

 

[belize1334]

^^ Well, fabricating a different mount isn't an options since the update has to be a direct bolt in. It would only work if the 7th or 8th gen rear diff was a direct swap.

As for the 4-bolt in a 3-bolt, I don't have the PS pump anymore so I'd have to buy one and reinstall it. In that case, is it possible to loop the lines so that the pump doesn't run dry and seize up. I certainly don't want to reinstall the 4ws system which is a huge disadvantage in autocross.

Edit Thoughts on 3-bolt 4-bolt hybrid. Iirc, the G-GSX has a 3-bolt non-lsd rear diff w/o 4ws. Is this correct? If so, the pumpkin is identical to the 3-bolt LSD pumpkin out of a 1Ga dsm. So, I could take a 1G 3-bolt LSD pumpkin and put a 4-bolt LSD in it. That would satisfy the update/backdate criterion since the 3-bolt is ostensibly from a G-GSX and would allow me the use of the less-breakable 4-bolt axles since the internals of the differential are unrestricted. And it would have the benefit that I don't have to worry about the 4ws pump getting mucked up.

 

[Muskrat]

Do the rules not allow a block off plate for the pump? I'm guessing that would be considered an "external modification"?

Have you talked with any officials to see if they'd allow eclipse part's, since they basically used the same parts in 91/92 (aside from the housing I suppose. no 4ws). The 4 bolt was an update to that design, and thus an update to ours, except production was discontinued. If you argue the case right I'd bet they'd allow it.

 

[belize1334]

^^ It's not clear to me whether removal of the pump constitutes modification of the external unit. It depends on whether you define the pump as part of the differential or part of the 4ws system (which can be removed since the GGSX had no 4ws and all galants are considered the same for classification).

As for the TEL, they are considered a different vehicle from galants and thus cannot be used as sources for parts under any circumstances unless the part is shared between both galants and TEL in which case they don't care where you get it.

I think I'll just swap a 4-bolt into my 3-bolt pumpkin and leave the pump blocked off. If somebody objects (which they won't locally anyway) then I'll source a GGSX 3-bolt pumpkin and use that.

Just FYI, the reason for doing this is that Street Prepared recently changed their class rules to allow the use of boost controllers and the elimination of fuel cut. The long and short of it is you can do any of the stuff we normally do (i.e. suspension, DSMLink, intercooler...) so long as the front bumper isn't hacked, and you use the stock long-block and turbo. But with a boost controller and A2W intercooler I could presumably be making 275whp in a class that runs over 2 seconds slower then street modified (where we normally live).

 

[vr4play]

I ran in esp with a 1g 4bolt lsd and it was never questioned. I think you can switch parts within the manufactures. Any mitsu part should be legal. I am now using an evo 9 rear diff with evo 9 inner axle joints. Unless you plan on going to nationals no one will ever question whats back there.

 

[JSchleim18]

I dunno if it has been mentioned, but why not just slap a DSM 4 bolt LSD rear on there as they came on some of the JDM GVR-4 RS or monte carlo models?

 

[raptorWagon]

Quoting vr4play:
I ran in esp with a 1g 4bolt lsd and it was never questioned. I think you can switch parts within the manufactures. Any mitsu part should be legal. I am now using an evo 9 rear diff with evo 9 inner axle joints. Unless you plan on going to nationals no one will ever question whats back there.



How is that working out for you? I know there had been discussion on being able to use the Later Evo rear differential.

 

[belize1334]

Quoting vr4play:
I ran in esp with a 1g 4bolt lsd and it was never questioned. I think you can switch parts within the manufactures. Any mitsu part should be legal. I am now using an evo 9 rear diff with evo 9 inner axle joints. Unless you plan on going to nationals no one will ever question whats back there.



In SP you can only swap parts from within the same model (for trims and years listed on the same line) and only for US vehicles. Since no US sold Galant ever had a 4-bolt it's a no go. You got away with it on your DSM since some DSMs had 4-bolts standard. On the other hand, if some other US galant (of ANY year) had a sweat swappable rear diff then we'd be in there.

 

[chucklesas]

I don't know of any other US Galants besides the VR4 and GSX that ever came AWD. Have you tried asking on thegalantcenter? (assuming that website is still around)

 

[vr4play]

You got away with it on your DSM since some DSMs had 4-bolts standard.



I never raced my dsm only my galant. Me and MJ Rosenfeld both ran in esp with 4-bolt rear diffs. We both moved to SM for more power. My car wasn't fun enough with the stock turbo and boost control. I am now in XP but that class is hard because there are basically no rules. Full race prepared cars on slicks. I think I can handle myself once I get a few bugs worked out.

The evo rear diff has been working out great. I plan to send it to TRE to be modded when I get some more funds. A quaife in the front is much needed on my car now though.

 

[belize1334]

^^ Ah, I misread your statement. I interpreted 1g 4-bolt to mean 4-bolt in a 1g not 4-bolt out of a 1g...my bad.

In any event. The reason I'm aiming for SP is that they lifted the boost control restriction as well as the fuel cut restriction. As such, anything you can do with a 14b - provided that you use traditional fuels and don't port it - is golden. So what used to be a 175whp class for us is now a 275whp class. The only restriction that remains really is that we can't hack the bumper for installing an FMIC. But with my A2W intercooler it doesn't matter cause the front core can be slim and sit behind the OEM bumper.

Now back to the rear diff issue.

15.1.C clearly says that "Equipment and/or specifications may be exchanged between different years and models of a vehicle if (a) the item is standard on the year/model from which it was taken, and (b) the years/ models are listed on the same line of Appendix A (Street Pre-pared Classes)." Since the Galant is listed on it's own line with the descriptor "all" next to it, I can put any diff from any Galant that will fit without modification but I cannot use a diff from any other car w/o being pushed into SM. Incidentally, this is also the rule that allows us to ditch ABS (instead of just unplugging it) and pull the 4ws system. Basically it's a cross compatibility with the ggsx which has the same braking system and rear subframe but has neither of the afor-mentioned systems.

The only allowance for differentials comes from 15.10.R which states that "Limited slip differentials are permitted. This permits locked differ-entials, either by design, welding, or mechanical means. Differ-ential cases, internal differential parts, and axle stubs may be machined as required for clearance and installation to the extent that material may only be removed, not added, and the exterior of the case may not be altered in any way. This machining may serve no other purpose."
Which is where I come to swapping the 4-bolt guts into a 3-bolt housing from either my gvr-4 or else a ggsx. And since (I believe) the housings from a ggsx 3-bolt and a 1ga 3-bolt are identically cast, I think I'll use one of those instead as their easier to come by and ostensibly the same once the guts have been pulled out.

Now, to be perfectly honest I'll never be nationally competitive in this car so I could probably just run a 4-bolt and nobody would ever know or care. And since it's more preventative maintenance than anything I wouldn't feel too bad about it really. Unlike a 16g vs. 14b which would fool most judges but gain me a nice little power boost. That I'd feel bad about.

 

[vr4play]

It sounds to me like rear diffs are pretty open in the rules and that you could use whatever you want including a kaaz and still be legal. The vr4 is the only specific housing. The 3 bolt and 4 bolt housing from the 1G and the GGSX are all the same. I have a 4 bolt already in a case here if you would be interested. Needs axles. I also have a 3bolt gvr4 rear diff here if you would want to run the factory rear housing. The pump won't turn without the ring gear that goes on the diff. I could install the 4 bolt lsd in the stock case for you. Also with the rear diff allowance you could run a stock evo rear diff and still be within the rules. It bolts right into the Galant or 1g case. Just need the stock inner joints from an evo and 4 bolt rear axles. The joints won't work with 3 bolt axles.

 

[gtluke]

I have a 3 bolt pumpkin with an evo 1 diff inside it. it's the same as a regular 4 bolt LSD
you can put the evo 3 mechanical LSD in the same spot. Will 2g stuff work in a 1g? If so the newer evo stuff will work.

 

[Struc]

Quoting Charles:
I don't know of any other US Galants besides the VR4 and GSX that ever came AWD. Have you tried asking on thegalantcenter? (assuming that website is still around)



Exactly what I was thinking. The last Galant in the US to have a rear diff was the 92 VR4 to my knowledge.

 

[belize1334]

Ok, then how about this. Can anybody tell me if there is any external difference (except for the back cover) between a GGSX 3-bolt and a TEL 4-bolt? The only way that I know to tell the difference is to look for the B1H on the rear cover. If that is the only difference, then I can just run one and it is ostensibly the same as having taken a non-4ws gsx 3-bolt and swapping the 4-bolt guts into it.

 

[vr4play]

The only difference between any of the rear cases is that the vr-4 has a hole drilled in it for the 4ws pump. The dsm and the GGSX have a spot for the pump it just isn't machined out. You are going to have to change axles and the stubs that they bolt to in order for it to work.

 

[iceman69510]

Maybe you could reinstall the 4WS pump without the gear driving it. It would look externally the same. Wouldn't have to worry about the fluid then.