How strong is the 4.2?

[pit viper]

Does anyone know what the rough power limits are for the 4.2 in the C5 A6 in stock form?
And when it lets go, what goes first? I know the 2.7 can handle a ton of power with just a rod upgrade, but not what the 4.2 can do.

[04A6SLine]

i think you're at around 300hp with stock limit. Also base on GIAC's chart, it can also give you another 20HP (which is more like 10-15HP).. so if you think about it.. a CHip 2.7t vs 4.2 are almost the same in HP..

http://www.audiworld.com/model/a6/04/04a64_2.pdf

[pit viper]

Ok, I didn't phrase that right. How much power can the engine handle before the rods/rings/head studs/etc... let go?

[04A6SLine]

LOL sorry yeah i guess it was more of my fault... you should give KINGOFNYC a PM. He put a supercharger in his V8 S6... so i guess he'll have more info

[A62TURBO]

Depending on the power adder involved I'm pretty sure you can push about 400-450 safely depending on the tune.

[SpooldYou]

First of all PES superchargers have a ton of drama surrounding the b6/b7 s4 motors. check out this Link (http://www.audizine.com/search/index.php?s=&cof=FORID%3A10&ie=ISO-8859-1&securitytoken=1235689648-86b44b13b2191460e62330ab2893c58737839544&do=process&searchthreadid=&cx=partner-pub-7993519228154114%3A8bu6v2-7eoi&q=pes+supercharged+s4&searchWhere=partner-pub-7993519228154114%3A8bu6v2-7eoi&sa.x=0&sa.y=0&sa=Search)

The 4.2 responds so well to mods and JHM has been making more and more parts for it. I believe they are running a 100-125 shot to a 6speed s4. Piggie Downpipes, K & N drop in, 2.5 Exhaust Should net you 290-300 whp w/o the Nitrous. I would do a search through there website or give them a call. They definately got there shit together. Unless you have the cake to spend on a supercharger. I'd say that your best bet is bolt ons. Hope that helps.

[redneck truck]

There's also a guy on quattroworld who built a twin turbo 6-speed S8 setup with K03's making 6 pounds of boost. Don't know what power it put down or how reliable it is, but he says it's a world of a difference, and it's on a stock fuel system.

[FrankA6]

I doubt the stock trans will hold up with 400+ hp

[redneck truck]

What do you think would give? There must be a reason they make insane clutches for these transmissions.

[SpooldYou]

Here you go Dug up a link.

Granted its a S4 But You get the Idea. I'd stay farrr farrrr away from superchargers and THIS specific V8.

http://www.streetfire.net/video/jhm-nitrousna-car-vs-vfs-supercharged-b6-s4_2035390.htm

Frank, The Combination of the V8 auto and N2O is heaven. I dont think these transmissions are as shitty as people think they are. Everyone forgets. when you take a Stock anything and almost double the output shit breaks. No one ever said it was cheap to mod a car. I know this all too well.

[redneck truck]

Spyker went the other direction - N/A, restrictor plate, 15:1 compression and made big power by revving upwards of 10krpm.

[A62TURBO]

I doubt the stock trans will hold up with 400+ hp

That's a different issue, he asked about the motor.

[G Men 08]

mmm I love that b6s4 exhaust note! I wish I could have gotten my a6 v8 to sound like that!

[Scotty@Advanced]

Ok, I didn't phrase that right. How much power can the engine handle before the rods/rings/head studs/etc... let go?

Rods are the same as the 2.7, so figure 75hp-85hp per hole. However the high compression pistons don't work well with boost, and IIRC they are cast. I'd wager probably 450-500hp being the limit of that the high compression ratio and pistons being the weak link.

Rumor has it the RS6 engine is good past 800hp but it's compression is a bit lower.

If ignition is controlled properly you can go further on Nitrous than forced induction.

[A4edwin]

Didn't king get his torque converter worked on?

[in2thenightaudi]

he had a new torque converter installed. Thread about his car here: thread (http://www.audizine.com/forum/showthread.php/284288-Say-Hello-to-the-first-Supercharged-S6.?highlight=supercharged)

[ChescoS6]

I dont think these transmissions are as shitty as people think they are.

Not to thread jack but I feel the same way. I've been on here for several years and have seen a lot of ZF bashing. I think a lot depends on how the car is driven, if you abuse the hell out of it trying to launch like a manual car then yeh it's probably going to F it up. I know there are many versions of ZF transmissions but I found these two quotes interesting in reference to the BMW 335d.. I would like to hear Scotty@advanced opinion.


The 335d features a 50-state compliant version of BMW’s 3.0 liter diesel inline six-cylinder, putting out 265 horsepower and 425 lb-ft. of torque in this application. Only offered with a six-speed automatic transmission – BMW says the engine is too torquey to mount up to a manual


From an enthusiasts point of view the one big disappointment with the 335d is the mandatory automatic transmission. Apparently BMW simply doesn’t have a manual transmission (or more specifically a clutch) that can handle the 425ft lbs of torque without exploding within a few miles from the dealer’s lot. Ok, it’s a good excuse. And the automatic is a great one. It’s the ZF six-speed that has been raved about in many other BMW products. FROM HERE (http://www.bimmerfile.com/2009/05/15/bf-review-bmw-335d/)

[Scotty@Advanced]

I would like to hear Scotty@advanced opinion.


Since you asked...

The ZF 5HP19 and 5HP24 (V8) are fairly stout gearboxes, they have had issues with one of the drums and the torque converter but for the most part are pretty good gearboxes.

The RS6 was made auto only because Audi stated there wasn't a manual gearbox up to the task of handling that kind of power (however incorrect Audi may be), and the same for the V10, V10 RS6, and all the other uber powerful cars.

However you also have to consider this from a manufacturers perspective.. With an automatic, the manufacturer can limit torque the transmission sees by gear selection or engine throttle, whereas with a manual the gear selection is not controlled by a computer. Auto manufacturers design their cars to withstand abuse by the most retarded drivers, and with a dumb driver and alot of power it's fairly uncomplicated to destroy a manual gearbox, however automatics are more idiot proof. Automatics are also inherently stronger by weight by their design. Manual boxes with their opposed shafts and gears are constantly trying to push themselves apart, meaning you need a beefy (heavy) case to keep parts where they need to be. More power = more beefy case etc.. An automatic can get away with a very lightweight case due to the sun and planet gears they use. The outer ring gear in a planetary gear set acts as it's own container and can easily withstand forces created by gears. Planetary gearsets can also be smaller and stronger than typical manual box gearsets as the multiple gears can be used in the planetary set, whereas for the manual box your pretty much stuck with a 2 gear cluster.

That is my opinion and I'm sticking to it.

[cag3937]

Friend just blew his s4 engine after he chipped it

[linust]

... I know there are many versions of ZF transmissions but I found these two quotes interesting in reference to the BMW 335d...


The 335d features a 50-state compliant version of BMW’s 3.0 liter diesel inline six-cylinder, putting out 265 horsepower and 425 lb-ft. of torque in this application. Only offered with a six-speed automatic transmission – BMW says the engine is too torquey to mount up to a manual


From an enthusiasts point of view the one big disappointment with the 335d is the mandatory automatic transmission. Apparently BMW simply doesn’t have a manual transmission (or more specifically a clutch) that can handle the 425ft lbs of torque without exploding within a few miles from the dealer’s lot. Ok, it’s a good excuse. And the automatic is a great one. It’s the ZF six-speed that has been raved about in many other BMW products.

Note that they refer to 6 speed ZF autos...that would be a generation later than the 5HP24A found in our C5 4.2's. Call me an optimist, but I imagine ZF learned a thing or two in later years :)


Since you asked...

The ZF 5HP19 and 5HP24 (V8) are fairly stout gearboxes, they have had issues with one of the drums and the torque converter but for the most part are pretty good gearboxes.

There are some tear-down pictorials on the 5HP24 showing broken clutch baskets (google is your friend). At one point, last year, rumor was A-clutch baskets were out of stock in N. America. Deteriorated F-piston seals kill reverse (did in a local AR owner, so this is true too on the 5HP19A as well)


The RS6 was made auto only because Audi stated there wasn't a manual gearbox up to the task of handling that kind of power (however incorrect Audi may be), and the same for the V10, V10 RS6, and all the other uber powerful cars.

Back on topic...Remember that the C5 RS6 had 450 hp stock. Back in the day, Champion's WCGT RS6 was rumored to put out between 550-600 hp before SCCA stuck them with tiny restrictor plates. I recall hearing that even at stock boost levels, they put out about 500 hp. So at least when adding horse-pressure, we have a decent margin!


.. With an automatic, the manufacturer can limit torque the transmission sees by gear selection or engine throttle, whereas with a manual the gear selection is not controlled by a computer.

GM calls it "torque management" and they accomplish it with a significant retarding of ignition timing right before the shift point. Really numbs the responsiveness of the throttle in my old-school Yukon. Some have coded it out of their ECUs, at risk to their already weak trannies.

[eagledubg]

whats the deal with this supercharger? Anyone try this? http://www.motodyne.com/frames/4.2LSC.html

[beemercer]

whats the deal with this supercharger? Anyone try this? http://www.motodyne.com/frames/4.2LSC.html

motodyne=scam

the hack attack won't die lol

[ben916]

Pit, if you are inquiring about the Audi V8 4.2 motor - look no further than the Gumbert Apollo for your Max power for the 4.2 (650/700/800hp)

EDIT:
Also if you are looking at a 4.2 NA or 4.2TT - check out Stephen's RS6 with all the Dahlback Racing goodies on RS6.com (search for Special Sauce) - 650hp/748TQ
All it takes is $$$,$$$

[Scotty@Advanced]

motodyne=scam

the hack attack won't die lol

Eghad don't mention he who will not be named! Soon a mysterious newly subscribed lurker will post "Evidence" contrary to all the negativity posted about Motodyne. For shits and giggles, google "Motodyne" "Murderdyne", and "Motodyne scam" and spend the next few days reading humerus posts.

[beemercer]

Eghad don't mention he who will not be named! Soon a mysterious newly subscribed lurker will post "Evidence" contrary to all the negativity posted about Motodyne.

so true, just happened maybe 3 months ago in the B6/B7 S4 forum

[c00teriyf]

i always wanted to play with a 4.2..id say do it. as mentioned they can handle somewhat decent power from what some people have done to them.

[TozoM8]

I really like mine. I probably didn't ad much on the top end (~50-70HP), but the low end torque is amazing. I have the tall (0.56) 6th gear from Scotty and I don't have to downshift on the hwy. Small turbos for very quick boost without lag. I can go as low as 35mph (1K rpm) in 6th and it picks up without hesitation. Excellent daily driver.

[eagledubg]

Eghad don't mention he who will not be named! Soon a mysterious newly subscribed lurker will post "Evidence" contrary to all the negativity posted about Motodyne. For shits and giggles, google "Motodyne" "Murderdyne", and "Motodyne scam" and spend the next few days reading humerus posts.

Haha will do

[speedtrapped]

Pit viper , u should just pull the trigger and buy my RS6 engine and tranny.....I have an extra with 73k miles on it leftover from my engine swap...last time I dyno'ed it mad 424/505 at the wheels, stock aside from stage 2 eurocharged flash, gutted dp's and larger SMIC...just a thought, and not to expensive

[G Men 08]

that would be a good time!

[mithril]

There are some tear-down pictorials on the 5HP24 showing broken clutch baskets (google is your friend). At one point, last year, rumor was A-clutch baskets were out of stock in N. America. Deteriorated F-piston seals kill reverse (did in a local AR owner, so this is true too on the 5HP19A as well)

You mean like this? As me how I came to take that picture :(

http://media.corrado-club.ca/albums/misc_pics/clutch_repair.jpg