Automatic Transmissions

[desotoman]

The 4L80 is the T400 with an overdrive gear making it a 4-speed. Just trying to find out if they run the 3-speed or 4-speed version.

John

The 4L80 is not a 400 with an OD. It has many similarities & internal components from the 400 but it is incorrect to call it a 400 with an O/D so don't confuse yourself there John. They are different animals.
  Sid.

John,

I don't know where you are getting your information but Sid is completely correct on this subject. There was never a Turbo 400 made with an overdrive from the factory with the turbo 400 name. The later 4L80 may share some similarities, but it is a different transmission even if is shares some of the same parts. When anyone talks Turbo 400 they are talking about a 3 speed transmission that is not computer controlled. When people talk about a 4L80 they are talking about a 4 speed transmission that the 4th gear is an overdrive and it was designed to be used with a computer of some sort.

I hope this explains where I am coming from on my question, and why I am confused on your question about how many gears the Waters Roadster has.

Tom G.

[ggl205]

I think I need a course in better communications. Originally, all I was trying to say was that the T400 and the 4L80E transmissions share the same 3-speed gear components. This is discussed in just about every technical article I have read on the subject. I never once said the T400 ever had an overdrive only that if one were needed to attain a certain mph, the 4L with an overdrive gear, would be the transmission of choice. Most certainly, there are differences between a T400 and the 4L but all I was looking at was which transmission is used in the Waters roadster. Very sorry for all the confusion on my part. I was just trying to get some additional clarity on the exact transmission the Waters team is using. From this discussion, it appears it is a Kilgore T400 with modifications.

John

[kiwi belly tank]

Detour alert 
Sid... redundant relays??? are you adding failure points or concerned that the relays are not reliable enough that you are giving parallel paths.  I trust you are using the totally sealed Delphi relays... not those kinda sealed parts store ones.

There's 19 relays in total & they're all quality German Bosch items.
The redundancy is in the direct-O/D control since there is one in front of each pinion & having one shift & the other not shift would be catastrophic. 2nd gear O/D is about 100mph faster than 3rd direct due to the O/D ratio & I have the shift set up so if I need to I can shift 1st-2nd-3rd-2nd O/D- 3rd O/D or skip 3rd & go 1st-2nd-2nd O/D-3rd O/D.
There's 6 electric oil pumps feeding two diff's, O/D's & T-cases, 2 electric water pumps, dual crank trigger ignition-EFI systems, blah blah blah, you get the picture. A smarter man wouldn't have started building this much liner alone.
  Sid.

[kiwi belly tank]

Yes John, they have a 3 speed no O/D.
A gearing calculator will tell you what you need & I'm sure you've already been there.
You ran a pretty small tire with the little Ford engine, do you plan to stay with that?
  Sid.

[ggl205]

The tire I ran in 2017 was a 25? front runner. The tire I have on the car now is a 22.5? M/T Bonneville. Looks like I will need something close to a 26? rear tire if I use the 2JZ engine and T400 transmission. Might be able to go smaller than 26? if I can get a lower (numerically) final drive gear than 2.56.

John

[JR529]

We run the 3 speed T400 with a ballistic trans blanket.

[kiwi belly tank]

The tire I ran in 2017 was a 25? front runner. The tire I have on the car now is a 22.5? M/T Bonneville. Looks like I will need something close to a 26? rear tire if I use the 2JZ engine and T400 transmission. Might be able to go smaller than 26? if I can get a lower (numerically) final drive gear than 2.56.

John

I presume your idea of going to a smaller tire is based on less drag, is that correct?
That actually creates more negatives than positives.
The smaller the tire the less traction it has & while you're talking about moderate power from a 2JZ at this time, that's still a bunch & you know down the road just like everybody else you're going to set it on kill.
Secondly, it takes more power to turn a big gear than it does to turn a big tire so you really don't want to be reducing tire size.
8k rpm is probably a good number for a 2JZ, 26" tire, 2.56 gear & .75 od gives you 322 mph.
If you're planning a 10 bolt you can move up to a 2.41 gear & come up with 342 mph.
Or a 2.14 that gets you 385 on paper.
All that driveline stuff is simple & cheap.
  Sid.

[ggl205]

Sid, the 22.5 inch tire was chosen specifically for the 2 liter G-class engine and Hewland 5-speed. With 350+ HP on tap and 10,500 RPM, I potentially can make a theoretical 250 MPH with power to spare. Realistically, I am looking for around 230 MPH if all goes well. Stainless and Bockscar 2.0 are capable of that speed too so it ought to be a great shootout for top honors. My car is prepared (or soon will be) for G-class competition for as long as the engine is available to me. All this discussion about automatic transmissions is preparation for if and when I move to Blown F-class competition. Anybody want to partner and get a blue hat?

With a 26 inch tire, you hit my number of 322 MPH with the 2JZ, .75 overdrive and 2.56 final but if I use the T400, I will have to make up for lack of overdrive with a numerically lower third member R&P. My car recorded a .24 Cd in the tunnel and that data can be manipulated to determine power required to make any given MPH number I put in. At 322 MPH, data says I still have considerably more power available but you and I both know about the theoretical at Bonneville. Darn near impossible to reach. If I can get close to 322 with the 2JZ, I will be the happiest guy on the salt.

John

[kiwi belly tank]

The highest ratio 10 bolt gears are the 2.14 (actual ratio 2.136). With a 1-1 trans (no OD) you could get there with that gear on a 28" tire with 8300 rpm, on paper!
  Sid.

[SPARKY]

love those 2.14 Ebay specials with Toreson diffs

[SPARKY]

you can buy pump drives for T400s not so for 4l80E you will have to make them.

[1leg]

The TH400 and 4L80 can both be had in a SFI approved case with bell housing. Now finding one might be difficult but they do sell them.

https://www.reidracing.biz/sh400-offdrag

https://www.reidracing.biz/pg400-bellhousings

https://www.reidracing.biz/super80-products

https://www.reidracing.biz/4l80e-bellhousings
 

[racergeo]

  Came across the story on a record holding street radial drag race 240 SX. Runs 6.60 @ 215mph and makes 2200hp. Transmission is a turbo 400. I know guys running in the 10's with near stock. Shift kit, 34 element sprag, good clutches. Car is called White Rice. Check it out

[ggl205]

Holy smokes! That thing is a beast!

John

[ggl205]

One more thing to add into the mix. I was told it is possible to direct drive a Th400 to the engine (didn?t say how) and push off in neutral. Get the car up to 30 mph and snick it into first gear. Now, this sounds like a good idea and eliminates the torque converter. Any atrocious downsides?

John