ddnspider

iTrader: (26)

I've had a stalled 4l60e previously on a bolton car and had fun with it, but it was a 12 second car and while it would 1.6x sixty, it wasn't all that impressive. This time around I decided I wanted to play with a centrifugal blower and knowing I was going to make some decent power, I started researching about the 4l60e and seeing all these horror stories of people blowing them up whenever they put any kind of hp behind them or went to the track with a tire on them. See HERE for my build thread.

Anyways, in my searches I came across THIS THREAD thread which made me curious. Specifically, this post from a GM Engineer, It got me thinking, we know that heat is an enemy of the transmission, but what if RPM and the change in RPM at the shift or the shock at the shift is the major cause. Could you have a setup that makes plenty of HP and tune it such that it would live when beaten on and taken to the track. So here's my line of thinking:

-Do the obvious stuff like run a good trans cooler.
-Keep the shift RPM close to stock. This is obviously going to give up power and mechanical advantage over someone willing to shift at 6800 rpms. But if the setup is designed around this max RPM range, you can still make plenty of power and have a blast and run decent times.
-Pull timing at the shift momentarily to soften the shock on the trans. I believe this is key and will show what I did in a later post.

ddnspider

iTrader: (26)

My setup consists of:

Futral F13 cam
D1SC running 5-7 psi depending on belt slip
Yank 3600 converter
STOCK 4L60E
STOCK 10 bolt with TA girdle
STOCK bottomend
Raceweight is ~3800lbs with me in it.

I am running a 40,000gvw trans cooler that is tucked into the bumper horizontally. It does not replace the factory trans cooler, but is inline so there's really 2 trans coolers. Some will argue to get rid of the factory one altogether since there is also coolant going through the radiator that can add heat to the trans fluid. I log my trans temps and I typically sit around 160*, while my coolant temps are typically 180-190*. Outside of this, I have no other modifications to the transmission or anything special.

Based on my logs and comparing with online calculators its making about 550rwhp or about 700fwhp since the blower takes hp to turn and has been like this for almost a year. Again its not crazy HP, but its also not your average bolt-on/cam car. The car shifts within 100 rpm's of my commanded rpm, usually 50 or less. The car rolls around the street on 295/50/16 M/T ET Streets so it doesn't just skate around all the time. The shifter never leaves [D] when driving. I just went 11.2 with a 1.67 sixty at 3800lbs at the track and everything seems to be doing what its told

ddnspider

iTrader: (26)

Here's where I think the real key is other than limiting the RPM. You need to strike a balance of softening the hit at the shift. You do that by limiting the timing when it shifts. The transmission would have trouble normally handling 600 ftlbs of torque THROUGH the shift....but by limiting the timing MOMENTARILY and only making say 350 ftlbs at the shift, its much less stress on the parts and then pour the timing right back in. Does this give up some time at the track, I would assume so. Is a couple tenths worth it to keep 99% of people happy and driving home after racing, I would also assume so So here is what I changed:

Note: These are EFI Live based table numbers and titles.

[B1902} Torque loss from spark retard- This is zero'd out.
{B6615} through {B6620} is all maxed.

I had to figure out what tables affected the final commanded timing at the shift. Working with joecar, he fed some info from the scan tool:
The one we want to focus on is Transmission Torque Reduction-
For Transmission Torque Reduction: see tables D0801,2,3; and also look at D2004 and its enablers D2001,2,3 and D0301. You will use these to set the percentage of timing you want to pull during the shift. See my example. You will have to do a little trial and error here. If you pull a percentage from 0ftlbs all the way up, your ramp rate of the timing will be very slow when the computer adds back in the timing. You want to do this so it only pulls timing right at the shift and then steps back up to your commanded timing based on your hi/low spark tables.



The trick that we couldn't figure out is that the above tables are looking at {B6605} TCS Spark Retard Torque Loss. Even though this is in the traction control section of the tune, this is still used as spark retard required to cause the desired engine torque loss when you set a percentage in the transmission torque reduction section of the tune. This is the key. You can play with the timing in this tables until you get the desired torque/timing pulled at the shift. Here is how mine looks:



If we look at my log, the 2-3 shift is commanded to shift at 6000 rpms. The car makes the shift at 6023 and drops from normal timing of 14 degrees to 8 and then once the car enters 3rd gear the timing ramps back up to normal. There's plenty of other modifiers like IAT, ETC, etc., but changing your torque reduction percentage and modifying the retard timing allow you to tailor you timing retard at the shift as well as ramp rate.

ddnspider

iTrader: (26)

So just to summarize, based on the searching I did and experimenting in the tune; it seems like a stock 4L60E can live at higher hp as well as track outings if you are willing to limit RPM and pull timing at the shifts. I am sure theres plenty of people who want to rev their stuff to 7k. This is not for them. There are also plenty of people who want to maximize their track setup, and this is also not for them. But for the average guy who wants horsepower and play at the track, I think this is a way to have your cake and eat it too. It means you must maximize your area under the curve for lower in the rev range, i.e. a wide torque band is your friend. You also have to be okay with giving up some timing at the shift which will slow you down. But overall it seems like a viable path to maybe make the trans live longer than alot of people see.

Game ova

What you are saying makes perfect sense. Basically the 60e has the same Achilles heel as a 400..... the sprag (high rpm and torque hurts them) . I know next to nothing about the 60e, but given how inexpensive a higher capacity sprag is (I'm assuming one is offered for the 60e).... and with it being serviceable by even a novice, it seems it would be worthwhile to change it to prevent failure. Hopefully I'm not in left field with my thinking.

ddnspider

iTrader: (26)

HMMMMMM, thats super interesting about the sprag.....makes me wonder how much the trans would hold if one swapped that out combined with the above tutorial.

Game ova

Yup. And btw, i would have NEVER dreamed of what youve done as far as changing the tune to help keep a tranny alive lol. Sharp thinking.

ddnspider

iTrader: (26)

haha, thanks man. It is a bit out there I admit.

bbond105

On the 4L60e we are stuck with a stock designed sprag. There are no aftermarket high capacity sprags made for the 4L60e.

wht/73

I have no skin in the game as I have an 80E with a compushift controller...but doesn't GM do something like this?
Torque management or is that something different ?

Game ova

Sounds to me like ddnspider might be on to something, I've seen thread after thread about failed 60e's. But his is living behind a pretty stout FI setup.

Marc 85Z28

iTrader: (8)

See post #19 from that thread.

Cam, boltons, converter, and a blower should be flirting with 9s at full weight, not running low 11s. I have no idea why you're handicapping yourself. A mildly built 4L60E by someone who KNOWS what to do shouldn't cost more than $1500 and will handle anything your setup can dish out.

Control the fluid properly (both hydraulically/mechanically and a proper tune) and the trans will live. It's been 11 years on my 4L60E and it's still going strong with 7000RPM shifts every time it's driven, full weight, with a better 60'/ET/trap than you posted in the other thread.

Spend the money, address the transmission and get that thing running where it should be. Forget the RPM limitation nonsense.

ddnspider

iTrader: (26)

You're obviously missing the entire point of this thread....and you have a built 4l60e so again.... irrelevant with the intent of this thread.
Oh...and I'm off by about 2-4 tenths so physics would disagree with your 9 second comment.

ddnspider

iTrader: (26)

1st thing everbody does is zero out torque management thinking it's needed to go fast. It's also very sloppy as far as adding the timing back after the shift.

Game ova

I kinda goofed it up as well, mentioning hardware that isn't even available for that transmission... when the whole point of this thread is to lessen the load on the transmission via the tune. Sorry.

ddnspider

iTrader: (26)

No worries. The entire premise that fluid is the main reason the 4l60e fails makes zero sense. There's plenty of people with fluid levels that are just fine and their transmissions still go up in smoke....especially when they add parts like high rpm cams that require revving the motor higher than stock.

Marc 85Z28

iTrader: (8)

No, YOU'RE missing the point. You spent a lot of money and time building your car, and yet you are foolishly and needlessly handicapping yourself and it shows in the timeslip.

That calculator is laughable. My raceweight is ~3700lbs and I made 420rwhp, yet I've run multiple 10.8-10.9 in the 123-124 range.

Good luck going out of your way to waste money and run slower.

Game ova

I dunno, sometimes people just like to be able to drive to the track....make a few light passes.... and drive home. It's not always about all out passes, often times a man has to work with what he has until he is either willing.... or able to get all the necessary components to make all out passes. There's nothing wrong with being easy on the car.... even if it does make it a bit slower at the track. Longevity trumps all else in street car world.

ddnspider

iTrader: (26)

You obviously have nothing to add to the thread then and I'm wasting your time, so move on to something that matters to you.

ddnspider

iTrader: (26)

Meh, whatev's, different strokes for different folks. All I'm offering is an alternative approach. Doesn't mean anyone has to take it.