Spridget Tech Talk (MG Midget & Austin-Healey Sprite)
Guys, Shawn @ Moss has just confirmed that MOss Europe will have the rare 3.55 back in stock soon read for delievery. They aint cheap but at least you guys can finally get one,. $551 US + shipping. I'll check and see if he can get some sent over here.
See #10 in link.
http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=11636#top
How is this one different from a stock one in terms of performance?
Jason
Lower revs at highway speeds. Less "pick up" but higher top speed if you have the motor to pull it.
IIRC 3500 RPM @ ~70 MPH
Would there really be a benifit if someone already has a 5-speed?
Even lower RPM's snd better milage on the highway but you'll have to downshift to at least 4th w/ a 1275 if you want to accelerate. probabaly will have to go to 3rd. There is a member who has both and likes it.
IMHO, the 1rst gear on the 5-speed is a bit too low anyway. Even with the standard 4-speed box a common complaint that the press had was that 1rst was too low. I can see how it might make the whole range a bit more useful, but yes you would lose a bit off the line. It'd be great for daily driving, but it might hurt your autocross/gymkhana times.
I could definitely be interested in one or even two of them. I wonder how soon they'll be available here in the US (through our US suppliers)?
I see two B's in your sig but no Spridgets. This is just for Spridgets, it won't fit the B.
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Not to worry. I have six Spridgets (and four Bs). I'm ready to put a deposit down, with Moss USA, on two of those 3:55 difs as soon as they are ready to accept them.
They are ready now. Here, everything you need to know:
http://www.britishcarforum.com/bcforum/ubbthreads.php/topics/829317/Re_3_55_Avalible_again_Am_I_re#Post829317
PM Shawn and tell him I sent ya.;) No finantial interests, just trying to help out.:)-D
Here it is back in the catalog ready to order:
http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29295
It'll ben nice to not have to tell folks the last remaining new set (mine) isn't for sale. Several people wanted to buy my set. Now anyone who wants a set can buy one!
Better get 'em while y'all can, I feel this will probably be a one shot deal. I sent my set off Friday to be installed in an extra diff. I can't wait to put them in!
$600 for a tiny ring and pinion? I hope they are made out of titanium, or maybe platinum... Lord have mercy...
Up until last week they weren't avalible at ANY price! FWIW, I was willing to spend more than that to get the last remaining new set I have now. Believe me, this is a deal. Shawn said they are having their "buy more, get more" sale in Feb. These quaslify for 12% off right off then bat. That's comes out to $528 which was less than they cost on Moss' Euro site. That's not even counting shipping them overseas. Yeah, $528 isn't a small amount of money, but it's cheaper and easier than a 5 speed or O/D swap. 210 5 speeds recently went for $800 on ebay. Then you still gotta get the kit (if it'll fit your engine) and put it in.
I hemhawed around when these were still avalible. When I finally made up my mind the were NLA. I hunted frantically till I found the last set. I just don't want to see that happen to anyone else. For people like me w/ a 1500 and dont want to cut your car, they are the only choice. This is one of the few mods that will actually pay for itself over time with better milage and longer engine life. Gas is expected to hit $5 a gallon this summmer. I'm sure glad I got my set!
Lol, by the time you have an engine ballsy enough to effectively pull that gear you will break every other part of the rear end.
would take an awful lotta miles to make up for $528 plus installation. i guess for those w/a 3.9 or 4.2 maybe. but 3.7 down to 3.55 is not really that much diff. (haha) i guesss it is nice to have the option, though.
Ron, you're looking at ~ 500 RMP difference @ 70 mph and ~ a 20% difference in engine wear. For me, that's a lot. Anything below 70 and you get run over around here. Mine is a DD and 150+ miles a day isn't uncommon. The 1500 isn't known for is high RPM longevity or reliability. My cruise RPM is usually ~4500. I need all the help I can get. yeah, I'll miss the "extra" off-line pull of the 3.90. It all depends on what an idividual is after. I also need to extend my touring range. (This meaning fatigue on the drive, not fuel.)
IMO, it isn't worth the extra money to go from 3.9 to 3.7; 3.9 to 3.55 is a different story (IMO of course, after all, it's someone else's money we're talking about.) With me, considering this is a "lifetime" car, the money I would save on fuel and wear is worth the cost. Where I live now a 3.55 or O/D is almost manditory. "In town" my 3.90 is fine. In Uptown New Oreans a 4.22 would be ideal.( for me at least.) I do agreethat if I had a 3.7 it wouldn't be worth the xtra cost to go 3.55. However, last I checked the 3.7 we're exactly cheap.
Not having to listen to my engine at 4500 rpm for an hour at a time is priceless. Excessivly high engine noise, as well as any other unwanted or unneeded noises wear me out.
Is this a good gear for someone who travels few miles at low speeds on hilly back road? NO.
The point of this post is, that those who wanted the 3.55 but couldn't find it now can.
I made a spreadsheet to compare transmission swaps to diff swaps. All for a 1275 of course.
Obviously a 1275/ribcase/3.55 would be pretty doggy so I went with a datsun 5 speed.
The interesting thing is that the datsun is so low geared in first and second that a 3.55/datsun setup is very similar to a 3.9/ribcase.
Here are the speeds in each gear @ 3000 rpm.
Ribcase/3.9 1st-15.7 2nd-26.2 3rd-37.0 4th-50.3
Datsun/3.55 1st-15.7 2nd-25.3 3rd-39.8 4th-54.9 5th-66.9
Ribcase/3.55 gear-speed at 3,000 rpm
1st-17.2 2nd-28.8 3rd-40.6 4th-55.3
Since most people are interested in rpm at highway cruising speed a ribcase with a 3.55 will turn just over 3500 rpm at 65 mph.
This website is fun to play with. If you know your gear ratios and tire size you can calculate all mph/rpm/gear.
http://www.f-body.org/gears/
Good website! Would have saved me some time.
I used 22 inch diameter tires in my calculations, it's nice to be able to enter tire size on that website.
To get gearbox ratios I used the rivergate5speed website, but that seems to be down at the moment. I found a website for datsun ratios but not for the MG gearbox.
http://www.datsuns.com/Tech/datsun_transmissions.htm
If I hadn't gone with a 5 speed I'd buy the 3.55's. I'm constantly catching myself getting to 4,000 in 4th and pushing in the clutch to shift...
It seems that I indicate about 4100-4250 rpm at 65. Who knows if the instruments are accurate, but it could be that the PO put in 4.2's...
I'll have to check
I have 4.222 gears in my car, I had assumed it would be 3.9 until I took it out. I tried 3.727 and the car felt quite sluggish in comparison. Still much better than when I had the stock engine, but nowhere near as fun as with the 4.2s. I'll be swapping back soon. I have a 5 speed and would still like to drop highway rpms a bit, maybe I'll try a 3.9 centre at some point, or otherwise wait until I install the supercharger and try the 3.727 again.
I have the Toyota 5 speed, sorry, should have mentioned that.
Sorry, I guess you'd probably like the ratios too! My gearbox is a Toyota T50, ratios:
First Gear: 3.587:1
Second Gear: 2.022:1
Third Gear: 1.384:1
Fourth Gear: 1.00:1
Fifth Gear: 0.861:1
Hope that helps to compare, what are the ratios in the Datsun box?
So the data I've found (Google, no responsibility!) shows the ratios for the other boxes as follows:
Ribcase
First Gear: 3.2:1
Second Gear: 1.916:1
Third Gear: 1.357:1
Fourth Gear: 1.00:1
Datsun
First Gear: 3.513:1
Second Gear: 2.17:1
Third Gear: 1.378:1
Fourth Gear: 1.00:1
Fifth Gear: 0.846:1
Ford Type 9 (Sierra)
First Gear: 3.65:1
Second Gear: 1.97:1
Third Gear: 1.37:1
Fourth Gear: 1.00:1
Fifth Gear: 0.82:1
Ford Type 9 (Capri)
First Gear: 3.36:1
Second Gear: 1.81:1
Third Gear: 1.26:1
Fourth Gear: 1.00:1
Fifth Gear: 0.82:1
There are other aftermarket ratios available for some of these boxes (I know there are for the Toyota and Ribcase boxes, I expect the Type 9 also), but these are the standard ratios, at least according to Google...
So 1st gear is slightly shorter in the Toyota box than the Datsun, but 2nd is a bit taller. It is true that first gear is over very quickly in my car, but 2nd gear pulls hard, and was where I noticed the difference most with the 3.7 ratio. Having said that, I do have to admit (and should have mentioned above) that I haven't yet spent much time at all yet driving with the 3.7 ratio (maybe 10-15 minutes) as I had a major clutch problem, and had to pull out the engine and box. It may be that the 3.7 grows on me when I get the engine back in the car, but my first reaction was that the car felt a lot slower.
It's possible that the difference is as much perception (due to taking longer in each gear) as it is reality. My other reason for trying the 3.7 (other than highway rpm) was that I found I run out of revs in 1st when competing in motorkhanas (your autotest I think? Very tight event driving around flags), and the 3.7 may yet prove a big enough benefit for that to make it worth keeping.
Interesting also that with my car, the 3.7 ratio and Toyota box results in almost identical 1st gear gearing to the ribcase 1st gear with 4.2 rear end (as the car was when I bought it). 2nd gear however is significantly taller with 3.7 and Toyota than 4.2 and ribcase. Kind of correlates with how it felt to drive actually.
2nd gear with Toyota box and 3.7 is near identical to 2nd in ribcase with 3.9 though... I'm thinking I might be a bit spoiled by the Toyota ratios, which I have to admit I really like, seem nicely spaced and work well for me as a hard driven car on the street and club level motorsport. I'll have to give the 3.7 some more time once I get the engine and box back in (hopefully this weekend), as on paper it should work pretty well with my gearbox ratios.
I just wanted to add an update to this, seeing as there is another thread running currently about 3.55 gears. After using the 3.7 a bit my opinion has changed completely. I really REALLY like my car with the 3.7. It has lost a bit of edge off the acceleration, but on a nice twisty road there is still plenty, and when I install the supercharger setup I have for the car it will more than make up the difference in acceleration. The gears are spaced out a bit more now, and that actually works really well on a twisty road. But the clincher is open road cruising. 5th is now a proper overdrive, I only use it on the highway, but I can cruise at 100km/h at ~3000rpm, and at 110 (our national speed limit) at under 3300, and 120 at ~3500. The difference this makes (compared to 3400, 3700 and 4100 with the 4.2) is MASSIVE, my wife and I can hold a conversation at normal voice levels (my car has a very loud exhaust), which was not at all possible before, and the difference in how worn out I feel after an hour on the highway is unbelievable. Of course with a car like the Midget you try to stick to back roads as much as possible, but when you need to spend time on the highway this has made it hugely more pleasant.
In case no one has mentioned this, the Datsun 60 series transmissions came in different flavors.
The 60L 5 speed is the Dogleg and was only installed in the 210 cars for 6 months in 1979.
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box 4th 3rd 2nd 1st 5th Rev
60L 4-speed 1.000 1.378 2.170 3.513 3.764
60L 5-speed 1.000 1.378 2.170 3.513 0.846 3.464
60A 5-speed A 1.000 1.378 2.170 3.513 0.821 3.764
60A 5-speed B 1.000 1.320 2.170 3.513 0.821 3.764
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