jbell

I'm doing as much research as my brain can handle right now.... Feeling a bit overwhelmed, decided to finally ask for help.

I'm doing a crazy swap, with hopes of daily drivability. We'll get into that later.

Right now though, I'm stuck with a 2.87 rear end. It's plenty strong, but sooo low. Puts a T-56 at like 1250rpm at 70mph.

I was looking into a 4l80e, which would give me like 2000rpm at 70mph.

Is that a more practical setup for daily driving, or am I heading in the wrong direction with less gears?

mrvedit

There is little reason to get a 4L80E unless you are running close to 600HP. Also the 4L80E has a tall 1st gear ratio of 2.42; combined with your 2.87 rear you will need 600HP to get the car moving. I don't think GM ever sold anything taller than a 3.23 with a 4L80E, often a 3.42 or even higher.
In contrast a well built 4l60E can handle 550HP and has a 3.06 1st gear.

jbell

So a built 4l60 is better... Good to know.
What about other choices? 4l70? Non-electronic?

mrvedit

A 4L70E is simply a newer model 4L60E with ISS (Input speed sensor). For some marketing reason GM decided to give their latest model a new number.
Similarly a 4L75E is a 4L65E with ISS.
Sponsors like RPM, FLT and Performabuilt sell 4L60E/4L65E which will be sturdier than a 4L70E.

I've done electronics for 50 years and computers for 40 years, so asking me about non-electronic transmissions/engines is like asking me if I prefer an iPad or a sliderule.

jbell

gotcha. I must have misread. I thought the 70 was a stronger 60.

So, what I'm looking for is a trans with at least short first gear?
Another option I was looking at was the toyota r154, geared like so:
3.251
1.955
1.31
1
0.753

better option i assume, based on what you said in your first reply.


edit: what about the 5L50 from the XLR?
3.42
2.21
1.60
1.00
0.75

mrvedit

GM made minor improvements to the 4L60E from '98 to current in the way of hardening the sun shell and input shaft, better sprag etc, but no fundamental improvements. So, yes, a 2012 4L70E is "stronger" than a 2000 4L60E, but a few aftermarket parts can make it much stronger yet.

I am not familiar with that Toyota 5-speed manual trans, but at least the gear ratios are good. Poking around on the Supra forum, it sounds like the clutch doesn't hold much more than 300 ft/lbs which any LS engine easily exceeds. No idea how much the trans itself can handle but it doesn't sounds like 400+ ft/lbs.

jbell

I edited my post above as you replied.
Is the 5L50 an option?
"The 5L50 can handle up to 311 ft·lbf (422 N·m) of torque."
Ratios are...
3.42
2.21
1.60
1.00
0.75

mrvedit

I don't understand why you are opposed to the 4L60E?
I don't think a 5L50 will bolt up, is weaker and doesn't have much in the way of aftermarket parts to strengthen it. The LS engine PCM also could not handle it.
What engine are you using and what are you swapping it into?

luigiandme

iTrader: (2)

^^^^ What its going in and what engine combo will determine whether you go 60e or 80e

jbell

CLK benz. Body is being race wired, so stand alone engine is a must. no chance of ever putting a stock motor back in there.

i'm looking to do a LQ build with an appropriate transmission for the 2.87 rear.
LQ means budget obviously.

I have been doing spreadsheets in excel all night trying to figure out what transmissions would be good. I have a few car that i've owned as a baseline, so I'm going from there.

Two options that look nice are the
6L80e, which has a 4.027 1st. (damn pricey, but "E" preferred)
Jeep T-5 which is a 4.03 (no idea on strength of it)

If all else fails, I can use the r154 from the supra and it's motor. that's my fallback, but I'd love a LS/LQ in there.

Oh, and I like the idea of building an auto car, with the possibility of adding paddles down the road, hence the E.

jbell

It seems like for the cost of a 6L80, i could have a 4L60, parts and then some.

"MAC"

iTrader: (1)

what rear end do you have? also you could just change the gear to like a 3:73 its a good DD gear as well. I have it in my WS6 and it runs good with no problems.

jbell

its a 2.87, made for their 4.3 v8.
I can't find any info on their v8's auto's ratios.

I'm stuck with that for now.
I know there are swaps available, since its a 210mm benz rear (from what i hear/read) but it's out of the question until I get this thing driving...

mrvedit

I doubt the huge 6L80E would fit in the tunnel of a CLK. It is sized and geared for larger/heavier SUVs.

What kind of racing are you planning? Road course with the car clubs or more serious with the SCCA?

"MAC"

iTrader: (1)

oh ok well honestly if you plan on making a lot of power or more power than a stock Gen 4 F-Body i wouldnt get a 4L60e the reason is bc i had boltons and my trans exploded i was making 335rwhp and 350rwtrq thru the stock 4L60e. when i added a cam it blew again so i had to fix my trans again they do not like extra power and they are only good for up to 600hp running thru them just remember they are pretty much an over drive unit for the TH350 in all honesty id go for a TH400 they are cheap and they can handle very good power when built properly.

"MAC"

iTrader: (1)

the 600hp is when the 4L60e is built to the max i forgot to say that

jbell

Plans... road course with clubs, buddies, lot meets, the usual "unofficial" stuff,

As for 6l80... I didn't look into sizing. I just saw vette, and assumed. That was dumb.

A TH400 has 2.48's with my 2.87 rear... no good.

The good news is that the T-5, from the Cobra has a 3.35 1st gear.... I should be able to get a chevy bellhousing and put it on a LQ4 block, No?

Eh, just read a dozen horror stories how LS's blow T-5's apart.

"MAC"

iTrader: (1)

I dont see why not if anything just drill it out so it can fit lol redneck engineer it

jbell

Yeah, but untested matching of parts gets expensive real fast.

I'd rather drop in a stock ford 302 and t-5 with the 3.35 1st gear than Frankenstein together something.
or the 1/2JZ with its 3.251 1st gear.

both options are better than the t56 and 4l60e. (both of which seem to be my only real option for an LQ block thus far)

"MAC"

iTrader: (1)

I woudn't diss a T56 they (when built) can with stand a lot of power. building a car to make it faster takes time and money. you are asking good questions and it seems like you wanna build it right the first time which is good but the 4L60e shouldnt even be an option IMO I wish I had just splurged for the 4l80e when mine had blew the first time. Either way what ever you decide to do good luck with the build.