4.2 40V engine Rpm increase

[daviesbike]

im just wandering what the max that the audi v8 can take rpm wise ?

have tuned rally cars added twin webbers,cat cams, titanium valve springs ect and removed the rev limiter altogether because of running launch controll with added rev limiter and have taken them up to near 9.000rpm

so was just wandering how the V8 would fair up to this kind of mod how well balanced is the engine and internals if the cams and valve springs were uprated would it take an increase of say 1-2,000rpm more ?

dont ask why i would like to know, im just intrested thats all and there seems to be nothing on the net with regards to this sort of thing,

i thought about getting an old 32valve engine and rebuilding it from the ground up just as a project no apparent reason other than i cant sit still too long or i will chew my own arm off

[Dezzy]

That is interesting Guy, buty got to be honest i'd quite like to see you chew your own arm off too.

Go on just rebuild one you know you want to, and then you can just find out what you can get to rev to, can you carb it? it would sound awesome snorting through weber 500's

[daviesbike]

haha i carb'd my rally car on twin webber 45's it dose sound fantastic,

i like tinkering with thinks like that when i have time so i would be intresting to see what the true limitations of the 4.2 are

[Nollywood]

The issue there is the crank and rods. Very heavy on the V8, you'll need to do a lot of lightening and balancing, with the flexi plate and torque converter. Oh, and an uprated torque converter would be a good idea.

A manual assembly is a lot easier to balance.

[ainarssems]

Not sure about crank/rods or 40V engine but on 32V engine S8 engines have solid cam followers with compensating piece for valve clearance adjustment instead of hydraulic ones on intake valves to save weight and to allow for higher rpm then A8. Exhaust are still hydraulic because of higher temp variations and higher change in gap due to temp change but use double springs. I still managed to get compensating pieces damaged on mine due to valve floating on high rpm.

These engines were not made with high rpm in mind. Even if you upgrade valve-train I don't think you can go more then 7500-7800rpm

Only way to know for sure what and how much needs to be done is to test, improve, test some more and again and brake a couple of engines in process.

[daviesbike]

MMM i see, was just curious as in the states there is a company that make H beam con rods and forged pistons the the S8 so thought that the diamiter would fit the A8 engine too