zinsavage123

I have recently been digging through the forum and some other sources, answers seem to be all over the place, so I figured I would get some of the pros input here now.

I am curious as to what the stock c5 engine and auto trans can handle. I seem to be hearing over 500whp is pushing it. Now I know there is no magical number, but I would like to have a general idea.

The a4 trans, I have heard things all over the place as well, some even seem to say the factory ratings anything over 350whp is pushing it, so who knows? This seems to be the issue finding out clear answers on, at least from my research.

I am curious on these things, because basically I would be looking into a vortech/procharger system, and want to know that with proper tuning can the c5 engine/drivetrain/a4 even handle it?

foggy

The short answer is: How Much Traction Do You Have

When you get Hook, then you'll find the weakest link in the chain.
If you are going with a supercharger and just street driving it, I think you
will be fine for a while.. Once you really start beating it hard/tracking it/ or getting
good traction, then you'll need to upgrade. And it depends on the condition of
your trans currently too

zinsavage123

So is it more so, these in stock form arent geared for the 1/4 that well vs WOT runs or from a roll to where less stress on the a4/drivetrain?

TX Z06 02

No, the less stress is from spinning the tires. Usually on the street, youre gonna spin, even with drag radials. But when the tires bite, then youre gonna find the weakest link.

At the drag strip, you typically always bite. Again, finding the next weakest link in the drivetrain.

Gearing applies somewhat here, since gearing is the multiplier for how much power you are making. Higher gears (numerically lower) means less likely to spin. But that only applies up to a certain power level.

Bill Curlee

Here are some WELL KNOWN FACTS.

1. When you modify a LS1 engine and add an aftermarket cam, you have to tune and change the idle speed. That usually requires a higher stall speed Converter. That causes more HEAT. A4s HATE heat! You will need an aftermarket trans oil cooler.

The 3rd/4th gear sun shell, clutch packs and the piston for that assy are WEAK. They break and or wear out. The A4 is full of components that do not react well to increasing engine TORQUE and HP.

Your trans may be fine for a while but trust me, you WILL find the weak link. Murphy will say it will be sooner than later!

There are TONS of You Tube Videos on A4 trans upgrading and repairs. Take a gander at some of those and see what were telling you. Here are a some for a start!

GM has an entire SERIES on the A4 and it shows you how it works, and how it fails and how GM fixed those failure prone components.




Here is the series starting with part 1. You can easily find the remaining Part 2, 3, 4 etc..


Hope this helps.

Bill

Brad Kirby

Volvo used this transmission in their twin-turbo XC90. Failures were very high, granted the vehicle weighed in around 4600 pounds but the engine only produced about 260 foot-pounds. That should tell you all you need to know about how likely the 4L60 will hold up to mods. The transmission is over its' head already. I really don't understand why GM used it in this car, oh wait, yes I do.

Volvo used that transmission as a stop-gap while they designed their own. You can buy a pre-2003 XC90 for a dime now because of the high failure rate. I think it was ASIN that makes the transmission for them after 2003, I picked up a 2006 XC90 with the Yamaha V8 for a song because it needed some suspension work. I spent some time researching the vehicle and found the only issue was in the 2006 (of course the one I have), the servos could wear the bores out, nothing an $800 servo kit won't fix. Otherwise it seems the transmissions hold up fine. Too bad GM didn't have ASIN build the transmission for this car.

zinsavage123

I am a little stunned a car with an engine this size, as well as being a v8 and gm's flagship vehicle at one point be equppied with a toothpick auto trans though, cant believe this has pretty much zero room for mods if 350wtrq is the limit....so many say at least.

Rob 02

They can be built up.

zinsavage123

Yeah, I looked at rpmtransmissions, guess that would be the first step, then the rearm just was hoping to have some play with some bolt ons at least without having to build a rear/trans lol.

Rob 02

I have a LS6 engine with slightly ported and polished heads, ~11.3:1 compression, CIA, and a mail order tune from ECS. I assume the engine is making around 440 RWHP with plenty of low end torque (not really big HP but fun). I do a lot of spirited street driving and I floor it once in a while and haven't had trouble yet. I wanted a RPM trans but I'm going to wait until mine starts showing signs of trouble.

It seems like 3rd and forth gear are the weakest link. Going with a higher stall converter would be hard on this trans. Like Bill said above. A trans cooler is a good Idea.

lionelhutz

What part of the LS1? The stock bottom end on a LS1 is likely fairly safe up to about 550-600 crank hp if you don't screw-up the tune or otherwise abuse it. For example, add turbos and lots of boost at a low rpm and that is more abusive then the boost coming on at a higher rpm. Change rods and pistons and the engine might be good for 800-1000hp, but when boosted to that level expect to see head gaskets or bearings becoming an issue.

The 4L60e is a pretty weak transmission. In stock form, GM put torque control algorithms into the PCM to limit the engine torque during shifts. So, they didn't feel the transmission could even handle the full torque output of a stock LS1 during shifting.

3rd/4th clutch pack, sun shell and input sprag are common failure points.

It can be upgraded, but at some power level (probably about 500-600 ft-lbs), you simply reach the point where it will fail again because all parts are being stressed to the level that one of the weaker part will give. The idea of a bulletproof 800hp or 1000hp 4L60e makes me laugh.

dankhts

Only good for max 350 hp like they come from the factory.... That's why I left mine stock......

Bill Curlee

The L460E has quite a few short comings in stock OEM form. There are hundreds of excellent You Tube Vids that discuss what they are and what needs to be done to fix them.

Better clutches and steels, improved Sun Shell, better bands higher quality software and improvements to the servo pistons ect.... The improvements alloy you to expand the power limits.

ADDITIONAL COOLING is a MUST especially if you install a higher stall speed converter. Heat kills the clutches, bands and software.

Talk a look on Google and You Tube and see where you stand.

Rob 02

In the math and Physics of it, there is the torque torque your engine makes and there is applied torque.

If you are in a light weight vehicle then then there is less mass on the system and less applied torque. The car is not pushing against a wall with full torque being applied.

If a lighter car, like the C5 corvette only weighs ~3200 lbs and moves pretty freely then the "applied torque" Is felt softer.

In a full on acceleration the drive-line may only actually feel 150Lb of applied torque depending on the load.

Rob 02

I'n Wikipedia I read that The 4l60e got an upgrade around 2001 with a stronger sun shell and a hardened shafts.

Again, I am not going to try to be on par with Bill on this topic.