We've been looking for other transmission options for the Berkeley salt flat racer we have. I came uppon the idea of using a T5, but swaping the 5th gear set so it isn't OD, preferably it would split 3rd and 4th and be somewhat closer to 4th. I know that's likely a custom pair of gears, but with only 120 CID to play with I'm not particularly worried about hurting a T5 behind that engine. Aside from the cost (to have gears custom made), and a funky shift pattern, what issues would anyone see with doing that? I know the engagement dog would likely be the minimum "minor" diameter of the drive gear, but i'm not looking for much below direct (1.14 or closer), and I don't believe I will have the extra power to expend driving an overdrive, even a T5.
Not sure I understand the purpose or need for 5 speeds where 5th isn't an OD, it would be a lot easier to just go get a T4 then. But the purpose of OD is to lower engine RPMs and reduce stress on it at highway speeds, also giving you better fuel economy.
Have you looked into Getrag 262 c and 262cr? If you find the right one it`s got perfekt stepped gears. five speeds, none overdrive.
A typical 4 speed or Richmond 5 speed transmission that locks up the mainshaft in high gear uses slightly less power than an indirect 5 speed in OD. A few HP might be a concern with your small engine
The above responses dont understand the problems faced on the great white dyno. I think its a brilliant idea to place another ratio half way between 3rd and 4th. I have no idea the costs involved, but I say go for it. You only need two custom gears. If you buy a used aftermarket trans with changable gear sets, you are looking at thousands to get what you need. You no doubt are looking for a 400 RPM drop between the top shifts.
You might think about using the .85 OD gears from the Chevy S10 T5. If you reversed these it might give you the ratio you need. Of course the spline in both of the gears is different but if you started with two sets of gears and with a little thinking I would bet you could machine the center out of one set and get them attached to the other set using dowel pins and bolts that would take the torque of your little two liter. You need to go to this web site http://www.britishv8.org/Articles/Borg-Warner-T5-ID-Tags.htm and look at all of the different ratio options then decide on the specific T5 you should start with and then, you can get the .85 OD gears from www.ttcautomotive.com. The shift pattern will take some concentration. Good luck. Rex
I've been a machinist for over 40 years and I'm telling you that you ain't gonna fucking believe what those custom gears are gonna cost you if you can even find someone qualified and having the equipment to do the job that is willing to do it. My advice is to consider something like a small sports car such as a Mazda Miata and see if ratios are right for what you need, maybe check for a Miata forum. Joe Varble, (chopnchaneled on HAMB) has a sideline to his Ford restoration and hot rod business of rebuilding Miata transmissions for guys who road race them all over the place. If I can contact him, I'll ask him for OK to send you his phone number and then get back to you. OK, scratch all this about Miata trans. Writing the above made me remember a friend who races a Miata in Autocross and I just called him and he says all Miata(s) are 5 speed OD. He also has a Porsche 928 which is a 5speed non OD but I expect you can buy a Richmond for less dollars, He did say that 99&up Miata a 6 speed was optional and 5th was direct. I can see your need to keep that small engine way up in it's power band by using lots of gears closely spaced, but I strongly suggest looking thru small sports cars stuff, as an adaptor for one of them will be cheaper to make than a set of custom gears, if you can even get the gears made. Dave
not sure of space available or if weight is an huge issue other than the obvious, but what a bout a gear vendors type unit such as the hone O Drive. These will 'split' the gears. The C4 vetts used a doug Nash unit on the 4+3. The later will probably the most compact and are fairly plentiful and cheap relatively.
I know a guy here in town who has 2 guys working for him in a teardown lot and storing parts in a warehouse that he sells online and he specializes in BMWs good thought zman. Dave
The problem with most OE type 5 speeds regardless of whether they have an OD 5th or a 1:1 5th is that they still have a pretty big spread between gears. The only difference in application is how they gear the rear end to cope with this. What you need is a true close ratio 5 speed like a Jericho, G-Force or Liberty. maybe even one of the old Doug Nash street 5 speeds. You can find them used on places like Racingjunk.com a lot cheaper than having custom gears made for a T5
http://forums.turbobricks.com/showthread.php?t=42399 take a look here for more confusing info about BMW's and Volvo's. Good luck.
Please post more info about your engine,trans and rear end. G Force Transmissions used to sell custom gear sets for the T-5. Look at removing weight from the whole drive train. Reverse and 5th gear should be totally removed. You could also look for a T-4 same as the T-5 just a gear short. I think it has different ratios than the T-5. Blind Elwood
The T5 5th gears can be swapped around and with some math you could probably achieve what you need, but your shift pattern may be weird...1,2,3,5,4
Thank you all for posting. Yes we can swap rear gears, but it still doesn't address the gap between the gears in the transmission. I have looked at an external gearbox, to use as a splitter, but they all add parasitic losses to the drivetrain that defeat their purpose in this car. Thank you for suggesting them though (hadn't checked the hone). Yes, I'm sure a Jerico can be built that would have the ratio spacing I need (IIRC they have a gear for 3rd that's available as 1.12, 1.10, 1.08, and 1.05) and if I was running between 800 and 1000 horsepower I could justify that box, or a Lenco. But they both take extra power to turn, hence my interest in modding a smaller box that from what I've seen should consume less power than either of the alternatives I've mentioned. As for more specifics about the drivetrain, the rear axle is a pr 1969 7 1/4 Chrysler. Why? Because the PO found it consumed less power than all of the then popular alternatives (9" ford, 8 3/4 Chrysler, Dana 60, ...). Can't fault him for that. I'm running in the unblown class, so no blowers, no turbos, no nitrous, I'm also running what SCTA calls gasoline, so no exotic fuels to assist me either. Point being, anyone that has seen the power curve of an engine this size, that has made the power we are talking about knows the power peak looks alarmingly like the cutting edge of a razor blade, and drops off sharply to either side. I do appologise for not including the power goal, as that is relevent, as it assists in demonstrating the issue I'm having with gear spacing; between 350-400 Horsepower. Yes, we will have to wind it, alot. Yes, there are others making that kind of power from that kind of displacement out there on the salt. No, I do not wish to discuss the engine further here, as it's a thread about transmissions. I would like to keep the RPM drop to less than 1000 rev. I had thought of having factory gears modified (bore the guts out of a smaller gear for the drive and press, weld, bolt, pin, furnace braze, whatever to the drive hub of another, with a similar process for the driven gear) but I thought of it after I posted this thread. (thanks for suggesting it, I might not have thought of that) Ernie, yes, it will be exactly as you describe, if I use the stock shift mechanism (looking into alternatives). I've seen several other 5 speeds, including the european ones, my primary concern with them is parts availability. Yes, I suggested custom pieces in the T5, but the rest of it would be either stock, or US made, so any of the supporting pieces (bearings, bushings, seals, etc) would be available. Yes, I would have to order them, and would still be SOL if they failled at B-Ville, but I wouldn't be waiting 6-10 months for something to show up from elsewhere, only to have it be wrong (for anyone that's been there, missed an event due to lack of the parts you need, you understand). Thank you all again for all the information, even the stuff I've already crossed off the list, as it reassures me that I'm not nuts for thinking of it. The big thing of course is not what I've already thought of, but what all of you out there in HAMB land might know that I haven't thought or heard of. So please feel free to post, I promise I won't bite.
I was starting to wonder if this thing had the power band of a semi-truck, but for a specific racing application it makes more sense.
OK, so I was right in assuming that you needed a true close ratio box. Since it seems that the Jerico and similar are out of the question, here's some thing else to look for. Back in the eighties I raced both a Datsun and Mitsubishi and both of them had close ratio non overdrive gear boxes through the racing departments. Additionally I had a Ford Escort (European rear drive car, not the US front drive thing) that had a DOHC 4 cylinder (Ford BDA) and a close ratio ZF gear box. All of these were designed for 4 cylinder motors, so there weren't huge amounts of mechanical drag.
DOM, I've been looking into the various motorcycle boxes, the Hyabusa is impressive, and there is a dedicated race gear and shaft set from Liberty, but I think the case is dedicated (built in) to the engine case (I haven't found one I can look at, in person or on the internet ). If it was seperate, and drove off the main shaft it should be fairly close. I have also been looking at some of the V twin setups (Harley, S&S, etc) and the Baker DD7 (direct drive 7 speeds) looks decent, but if I'm looking at their schematic correctly, it drives off the counter shaft, so the output shaft turns the opposite direction of the input shaft (makes sense, as the primary drive is on one side of the bike, and the output is usually on the other ). Hence my interst in the T5, I suppose I could hook the output of one of the bike trannies up to a set of quick change gears, to reverse the output, but then I'm adding drag again. Don, if I could find a couple of those it would be great, but the concern I have is parts. ZF makes some great stuff, but there are people I know that can't get parts for their ZF truck trannies, from the late '90s (as I recall the BDA Ford ZFs were older and less common, but maybe that isn't as big an issue as I think it is?). I wouldn't have an issue with the Mitsu or the Datsun / Nissan either as the Japaneese definetly know how to make an effiecient gearbox. I've also sent an email to Saenz as they make (or at least sell) a racing transmission that looks apropriate for a smaller displacement unit (they list two, one that is likely in competition with the Jerico, and a smaller one, I asked about the smaller one, it's available as a sequential too ). Sequential would make it easier to package the shifter in the microscopic driver's compartment we have in the car. If that isn't feasable, then we will figure out a way to put a "regular" shifter in there, but that's one more thing to do (does anybody know of a cable shifter for the T5?) .
G Force Transmission T-5 http://www.gforcetransmissions.com/tran_gt-5.asp click on the gear ratio chart upper right of page 2.0 Ecotec 371HP @ 9800+ Race Gas Blind Elwood
For US guys who may not be familiar, some euro spec 5 series BMWs in the 1980s used the Getrag 262 (my daily driver is a euro 5 series, it had one originally.) You can find them occasionally but they are pretty uncommon in the US. They're reasonably strong, but it will depend on the horsepower of your engine.
Rex was headed in the right direction. I did this with a road racing Fiat. I gathered up three different gear sets. All I needed to modify was the cluster gears, because the driven gears were individual gears. Here is what I did: 1. Have all the cluster gears annealed. 2. Have each gear cut off the cluster. Make sure they are all the same width. Match the width of the driven gears. 3. Have every gear drilled radially for 5 or 6 drive pins. Have all the cluster spacers drilled to match. 4. Drilled shims/washers might be needed to fill where the cuts were made. If the gears and cluster spacers are cut right, shims/washers will not be needed. 5. Have all the cluster spacers and individual gears reheat treated. Now you can mix and match the different individual gear sets to make your own cluster gear set. The gears are kept from individually rotating buy the 5 or 6 drive pins. I used drill rod for the pins. You would only need to make two new drilled gears and one cluster spacer set to keep costs down.
No, you do not want an overdrive for your application. You want direct in 5th or top gear. In case you don't know it any gear can be changed in the Richmond 5 speed. You can have anything you want. They have one model with spur gears and that would also shave a bit of loss off. Parts are readily available and the whole thing is reasonably priced. I have one in my car with a Long shifter and you can shift it so fast it sounds like a Lenco.
^^^^^^^^^^^^^Listen to Pete, he was first racing on the salt when Ike was elected! +/- a few months! BTW, I have T4, the non OD version of the T5. Having had it open, I dont think you wanna mess with it. Not real beefy.
Pete, I haven't looked at a Richmond in a while, I'll check them out. Trent, I know the T5 isn't as strong as a Richmond, or any of the other racing transmissions out there, but I believe it to be the least ammount of parasitic loss that could survive in this application I was only interested in changing the 5th gear set around, as they are splined onto the main shaft and cluster, but that's good to know about how to shift the other gears on the cluster, if I ever need to, thanks Drill rod pins sound like they would work, especially for no more torque than I'm dealing with.
Erik, How much of the short course do you use? What speed do you pull away from the push truck? Have you thought about a good aftermarket 3 speed transmission? I fully understand that you want to set a record at Bonneville, but the T-5 is holding you back. At some point your going to want to add horsepower,turbo,Nitrous or maybe a class change to F or E and go really fast. The T-5 will not last long then.A good transmission will serve you well for many years to come. Elwood
The Jalopy Journal
