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Discussion Starter · #1 ·
Has anyone measured the spring rates and specs on any of the boost valve springs that are used in various 4L80E applications? With all the offerings, it would be nice to know what's what. Granted some information is published to provide a general idea on what some of these resulting pressures will be when using a specific spring as intended, and one should follow directions and not mix and match springs with certain setups, but I've read about some interesting mix and match combinations and the resulting line pressures. This is more out of curiosity than anything. Let's see... we have off the top of my head...

Sonnax LB1 spring
Transgo SK-4L80-E spring
Transgo HD2 green spring
CK performance purple spring
CK performance orange spring
Superior K4L80-E blue spring
Jakes Performance High Pressure spring
Extreme Automatics Billet VB spring
Stock TH400 OEM spring
Stock 4L80E spring

Damn that's some springs. I'm sure there's a yellow spring and a red spring out in the wild too, maybe even a pink one?
 

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There's some data out there. We quit using the Sonnax LB1 springs due to inconsistent pressure. Same trans, same day, swapping springs from new boxes pressure would vary from 165-235 on the dyno. Spent a ton of time chasing pressure on the dyno. 4 out of 5 would make the 190-200 we wanted to see then one would be off. So we would have to change the spring out.
Some other builders have measured the spring tension and rate and found them to be inconsistent on a scale too.

Superior Spring and boost valve makes about 175-185 from memory.

We have two different springs but they make 190 psi and 210 with a stock boost valve diameter and shim.

Stock 4L80E spring makes about 160-165 usually.

Stock blue 400 spring in a 4L80E makes about 190.
 

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Discussion Starter · #3 · (Edited)
Hi Jake, thanks again for taking the time to respond. This info is much appreciated and gives me a better idea. 165-235 is quite a swing.

So in your stage 3 builds, the 4L80-3A for example without a transbrake, if a customer's application is a street/strip build that will see the occasional 1000 hp at the track when turned up, do you go with stock boost valve diameter, stock shim and stock sleeve along with a 190 psi spring, stock OE bumper spring and the line to lube mod drilled at say 5/64" and stock PR valve, or do you run a spring that is less pressure since there is no transbrake? I'm all set on your D3 transbrake application which I use the HD spring that came with it on my personal car as your instructions on what to do for that was very clear. Just curious on how the level 3 build with no transbrake is handled in terms of max line pressure/spring choice and if the EPC is kept. I see statements like "The use of fixed line pressure is necessary @ 1000 plus horsepower with automatic shift controls." which conflicts with other information that I've received.
 

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I like doing fixed pressure for anything boosted because people don't or won't reprogram the epc for map vs. pressure instread of tps vs. pressure.
If you are running fixed line pressure (with epc plug), you need less spring for desired pressure because the epc isn't bleeding off. For example- stock spring will give you 190-200 with plug.
 

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Hi Jake, thanks again for taking the time to respond. This info is much appreciated and gives me a better idea. 165-235 is quite a swing.

So in your stage 3 builds, the 4L80-3A for example without a transbrake, if a customer's application is a street/strip build that will see the occasional 1000 hp at the track when turned up, do you go with stock boost valve diameter, stock shim and stock sleeve along with a 190 psi spring, stock OE bumper spring and the line to lube mod drilled at say 5/64" and stock PR valve, or do you run a spring that is less pressure since there is no transbrake? I'm all set on your D3 transbrake application which I use the HD spring that came with it on my personal car as your instructions on what to do for that was very clear. Just curious on how the level 3 build with no transbrake is handled in terms of max line pressure/spring choice and if the EPC is kept. I see statements like "The use of fixed line pressure is necessary @ 1000 plus horsepower with automatic shift controls." which conflicts with other information that I've received.
Pressure needs are based on the power of the vehicle. Weight, gear ratio, etc have some play too.

We do fixed line on anything performance oriented with real power because experience has taught us (the hard way) that even knowledgeable tuners foul this up. I can tell you that we can dyno test a trans with 200 psi pressure, send it out, it get burnt up before ever leaving the shop at the installer/tuners place, we get it back, it still have 200 psi pressure before teardown, we teardown and have multiple clutch packs burnt, forward pack welded together, and guess who gets the blame?
Fixed line solves that issue.
Now you just have to get people to fill the fluid all the way up.... "But I put 6 qts in like it says online!".


A Powerglide, TH400, 350, C4, etc all use fixed line with a transbrake, so no reason no to for a 80.

The prevalence of turbo combos also dictates this as mentioned in this thread. When you can be making 70% power at 30% throttle, the line pressure curve shouldn't be based on TPS. MAP would be better but tooners still foul that up.
For some reason it seems that the numbers displayed in the graph of many tuning softwares gets taken as line pressure when there isn't any internal transducer reading it. Those are just made up numnbers. Tooner has no feedback loop like a wideband 02. Well actually they do. It's the burnt clutches in the pan.
 

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Jake is dead on. First couple units I built for turbo cars had D1 brakes with epc. They came back with burned up intermediates. Found out real quick fixed line was the way to go.

Jake, do you more pump wear on fixed line units that retain lockup?
 
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