floman

iTrader: (54)

I recently purchased a 98 SS Camaro with a LS3 conversion that is somewhere in the 450 rwhp range and about 600rwhp on 150 shot. Car currently has a Century built 4L60E tranny w/3600 Circle D converter, Moser 12 Bolt w/4.10 gears & 275-60-15" M/T Drag radials. Car is full weight non stripped down car. Has supposedly run 11.21 @121mph with approx 1.57 60ft. on motor and no times for nitrous runs.

Tranny acted goofy a few days ago and I'm afraid its on its way out

I really dont want to put money into another 4L60E, so I am looking into doing a 4L80E conversion. I know on motor only its probably overkill, but with 600rwhp on the nitrous I feel its a worthy conversion. I would rather do it once and do it right if it wont totally kill the cars performance.

My question is: How much 1/4 mile ET diff am I going to see changing over to the 4L80E with the different gearing of the tranny and heavier rotating mass, assuming the same stall speed & STR on the converter? Any of you guys have real world comparisons? I realize I will probably lose some performance, but hopefully gain a whole lot of reliability.

1) Approx ET loss?
2) 60ft loss?

01ssreda4

iTrader: (96)

If you don't plan to do much more modding I'd say a well built 60 could handle what you are throwing at it. As for your original question, it may be difficult to answer but hopefully someone has some direct back to back info for you.

floman

iTrader: (54)

This was already a stage 3 build from Century Transmission around Houston, the guy I bought the car from had a receipt for $2800.00. I just hate to throw more money at it and have the same problem in the near future. I have seen and heard of too many 4L60Es biting the dust.

Thought if the 4L80E wont kill the car too bad, it would be money well spent. If I need to I can get the converter for the 4L80E a little looser to help make up any 60ft loss and hopefully not blow through it too bad on the nitrous hit?

Anybody with real world comparisons would care to shed some light on the subject? I don't want to go backwards, but I don't want to keep fighting problems either. I don't have the funds to keep building 4L60s, that's why I say do it once and hopefully be done for quite a while.

mrvedit

This thread covered the topic pretty well:

https://ls1tech.com/forums/automatic...ile-times.html

Note that some people reported quicker ETs with the 4l80e due to its tighter gear spacing.
The additional 30 lbs makes little difference in a 3000+ lb car.
(According to Jake the difference is that small without the converter.)

The additional 10 lbs of rotating mass is also minor, about the same as the difference between a steel and aluminum drive shaft. Perhaps a 5 HP loss due to higher internal friction.

Perhaps better to compare the ET difference between the 4L80E and a 4L60E that blows at launch - about 3 weeks.

01ssreda4

iTrader: (96)

You completely pulled that pile of crap out of your ***. You can't just make up laws of physics dude

itsslow98

iTrader: (18)

I bet with a 4l80 and transbrake leaving on the bottle the car would go LOW 10s maybe high 9s. If your not doing a transbrake id have someone like FLT build the 4l60.

mrvedit

Partly true but it reflects the opinions of many others from the numerous previous threads that have discussed the differences between 4l60e and 4l80e. I mostly wanted to counteract the incorrect "huge penalty" reputation that some people have of the 4l80e.
I also recall seeing dyno numbers from someone who made the swap with no other changes and they were 5 HP down.
Its been a long time since I was in school, but I learned physics well enough on my own to get advanced placement credit at UofMich and then took a bunch of college physics courses for the fun of it.

I certainly defer to your much greater experience...
Are you suggesting the losses are higher or lower?

carlsonauto

Pulled from his *** or not he was trying to say that the difference is going to be minimal between the two as far as power loss and he is absolutely correct. As much as I am a fan of using the lightest parts as much as possible the ET difference between the two as far as weight will be minimal if any. As stated the gear ratio may indeed help ET....

floman

iTrader: (54)

Keep it coming guys. I would love to hear and see about some real world experiences. I'm pretty sure this is the direction I am going.Just need to sell a few more parts to help fund the project. If anybody needs something please feel free to check out my for sale ad.

01ssreda4

iTrader: (96)

Well now, it's all relative to what we are talking about. There is no "set" loss amount other then the weight penalty which is constant.

RonSSNova

iTrader: (3)

The overall gear ratio in first is 12.54 with the 4L60E.
With the 4l80E it will be 10.16.

So theoretically, you will lose in 60ft.
You could change the rear gear, but you would have to change it a lot to get back to the same overall ratio in 1st. Then you may run out of gear at the finish line.

You can leave the gear the same, but add more converter.

Short of someone posting real world experience, I think it's a try it and see and live with the consequences.

BTW, as you know, it's tough to have a converter that works both on and off the bottle. You have to compromise in one direction or the other.

Ron

poorhousenext

I don't know squat about about HP loss due to weight, so what about RPM lost and retention between shifts effect on ET. Could the 4L80 have the edge in 1/4 by it's gearing doing a better job of keeping the engine higher in power band between shifts.

4l65/70
3.06
1.62 -- 52.94% (high) RPM Retention 47.06% RPM DROP
1.00 -- 61.73% (high) RPM Retention 38.27% RPM DROP

4l80/85
2.48
1.48 -- 59.68% (high) RPM Retention 40.32% RPM DROP
1.00 -- 67.57% (high) RPM Retention 32.43% RPM DROP

floman

iTrader: (54)

Yeah, I have to agree with all of your statements. I did a little calculating at work night before last and came up with the same gear mutiplications that you stated.To have the same overall gearing(as the 4L60 has with 4.10s) with the 4L80 (I would need 4:88s to match 1st gear multiplication, and 4.56 s to match 2nd gear multiplication) and finally things equal out in 3rd gear. The only advantage of the 4L80s gearing is that each gear change has less of a drop in rpm.

Guess I could buy a 4L80 with a brake and slam it outa the hole on the spray and make up the difference

Its a tough decision, I guess most of the guys doing the 4L80s are big power adder guys that dont need the gearing that the 4L60s add to the overall equation. Maybe I just need a BIG TURBO pull out the slack.

bmf5150

I would go 4l80

poorhousenext

You need to take into consideration gear blow thru 4L60 Vs 4L80. Gear blow thru is lenght of time engine will be a lower gear before it's shifts to the next gear thus losing the mechancal advantage of gear.

So blow thru 1st quicker, your in 2nd, while competion still has mechanical advantage of it taller 1st to help it engine continue down track farther, 2nd same, now trans shifts into 1:1 gear where competitions higher gear ratio 1st and 2nd still has advantage of engine having the mechanical advantage of 2nd gear farther down the track to help accelerate cars weight.

Lets just call 4L60 lower 1st and 2nd a washout or maybe a disadvantage if you again take into consideration RPM lost between shifts that the engine has to pull thru that 4L80 doesn't have to.

Model 4L60 with 3.70 rear gear, 3000 stall, 430HP LS3 in 4t gen camaro base weight 3700 lbs. Don't have a model of same combination with 4L80E. If I did we might be able to see advantage or disavantage of lower 1st and 2nd gear and their effects on 1/4 time and mph.

Smo's04Gto

iTrader: (8)

See post 2 and 3 some great info , by one on the best tuners in the country.

https://ls1tech.com/forums/automatic...mony-faqs.html

mrvedit

Thanks for finding the link to the dyno comparison. I certainly remember reading it, but could not find it during my search. I thought I remembered the dyno difference as 5 HP, but it is actually 5 ft/lbs for the peak (about 1%). Due to minor test differences the author estimated somewhere between a 5 to 15HP loss.
So as not to be (somewhat correctly) accused of pulling something out of my rear, I will not venture a guess where the loss comes from, but suggest it simply be accepted as a fact.

01ssreda4

iTrader: (96)

I appreciate any intelligent leads, whether they agree or disagree with myself. While your link provided interesting data, still close to impossible to lock this down to a T. And the loss IS revolving. Meaning it will be different in every car. It will never stay constant, which just adds to the complexity of the question. I only commented towards him because it was someone making blanket statements based on his imagination, which is just plain silly