Is there anything that can be done to reduce the friction losses in a manual 5 speed trans normally fitted to a Honda "B" series engine? Currently, I have an S80 trans with LSD.

My application is a 1990 CRX Bonneville Land Speed car. I only need to upshift through the gears once, in no real hurry. No slamming the gears like a drag car. I have driven big rigs, so I am very familiar with pausing and matching rpm while shifting, and I don't care if the synchros work.

I am thinking of something like 0W or 5W synthetic gear oil. Anything else commonly done on race trannies? Ceramic bearings available? I'm planning on removing the LSD.

Thanks,

Jeff

 

You could get everything WPC coated? That should reduce friction. Im sure a full set of ceramic bearings would cost tons, and they aren't THAT much better.

 

While I appreciate your concern for friction, frankly, there are more important items that could considered for a land speed record. Tires, body design, etc.

 

While the trans may seem a minor issue, drive train losses usually estimated at 15% seems to leave a lot of room for improvement.

Clearly increases in engine output are desired, as well as improvements in drag, it is best to consider all sources of power increase as well as parasitic and drag losses.

Jeff

 

I would try oil additives over changing any parts.

A good experiment!

Set-up:
Remove transmission from car (if not already done)
Set on blocks, insert axles, support axles on v-blocks (or just jack stands)

Test:
Fill with your regular fluid
Shift into 5th (using a screwdriver on the selector shaft, rotate CCW and pull back)
Spin the input shaft with a drill or something to get the oil everywhere
Find a way to measure the resistance of turning the input shaft

Repeat test with different fluids/additives and record results, see what the actual difference is.

It will take time and some money (fluids), but this is the kind of stuff it takes to get every last bit out of every part.

 

Work around the 5th gear synchro setup, I would start with grinding off that little "tab" that aligns with the case slot.

You'd really be surprised at the amount of drag it causes.

I did a little "testing" this week......

 

You can't be serious?

 

Without that tab, reverse won't have a functioning synchro. If you're going to remove the tab, just leave the stopper plate, cone, needle bearing, and synchro and save some weight.

Use Torco RTF. There are treatments and coatings available, as well as straight cut gears (probably not in the ratios you need that can get by without a cuff) and dog engagement. Ceramic bearings are extremely expensive (I've used them in the K series).

 

Do straight cut gears really reduce friction? I thought they were just stronger, but made a buch of noice, hence why they aren't used.

I would only need a low friction gear for 5th gear, and right at something near 1:1 ratio (or 1.0).

I'm not familiar with the tab for reverse, but I really don't need reverse. Cars are usually towed or pushed.

I was thinking of a way to measure drag. I thought about using a drill and measuring the current draw.

Jeff

 

How much/what improvement was noted with the ceramic bearings in the K series?

Thanks,

Jeff

 

Yes, much less friction than a helical gear. MFactory has a 1.028 straight cut 5th.

You'll want as little friction in each gear as possible since Honda's are constant mesh transmissions.

I can't discuss the gains that were seen with the ceramic bearings.

You can measure the efficiency of a transmission on a transmission dyno.

 

I can guarantee the gains from ceramic bearings are not anywhere near worth the money. You would be better off putting that money into the engine or bodywork (aero package). Now the straight cut 5th would be worth looking into!

 

I hadn't realized the gears on the trans were actually in constant mesh. I haven't actually looked at the gears, but I guess there are drive dogs on the sides that have the gears sliding sideways on splined shafts to engage the dogs. If so, then yes, all the gears are constantly spinning.


How about an auto trans? I suspect I could get a locked torque converter, kind of like the circle track guys use on a powerglide, because I can push start the car in neutral, and then pop it into gear at 10 or 20 mph, whatever, and then floor it. I understand another big loss is the hydraulic pump inside. I can remove that, and drive a hydraulic pump outside the trans by an electric motor, just like my engine oil pump to eliminate that loss.

Any ideas about an auto trans with locked converter and separately driven hydraulic pump using less power than a 5 speed manual? Are there manual shift valve bodies available for a B series Honda auto trans? Will the trans handle 150-400 hp?

As far as work on the aero part of the car, I assure you plenty of effort is being spent in that capacity. As an example, since most of the classes I will run do not require front air entrance for cooling, I will have that plugged with air dams, and just use a solar type water to water heat exchanger and carry about 10 gallons of cold water to heat during the run.

Jeff

 

Not sure about the auto trans, but you'll gain a lot of weight with it, especially adding an external pump.

 

I really wouldnt mess with the trans. Fresh fluid, and MAYBE a straight cut 5th and FD.

And there is ALWAYS more aero work to be done. Add a boat tail, that is where the best aerodynamic gains will be made with almost any street vehicle.

https://www.google.com/search?q=civi...=isch&imgdii=_

 

Can't really do any body modification rear of the firewall, except a spoiler, or a few things in competition coupe.

Jeff

 

You don't work with transmissions much do you.

Using a straight cut 5th alone won't do much of anything. There are two OTS straight cut FD's for the B series, one is a 4.928 and the other is a 4.2 that is over $2,000.

 

Well he is looking for every last ounce of performance isnt he? What do you suggest he do? Spend a small fortune on ceramic bearings?

As I said before, fresh fluid is a must, but if he really wants to do something to the tranny, then those would probably be the best options.

 

If he wants every last bit of performance, then he'll need straight cut dog engagement 1-5 (MFactory PRO 1/2, MFactory Road/Race 3/4/5, all face plated), WPC treated, ceramic bearings, the right clearances, and some other items I won't mention.

 

How about a Liberty Face Plated gear set. Instead of using the Liberty Cuff to delete 5th, see if they can face plate 5th gear as well.

 

Read my last post.