Project Audi V10 5.2 Performance S6 / S8

vtgt · December 8, 2019, 5:54pm

CountVohn:

Now back to the performance parts of the build. Last time we talked about the JHM intake spacers and their ability to help keep the 5.2 V10 heat issues in check. While the spacers are helpful at keeping the motor cooler and more efficient the motor could also beit from shedding some of that unnecessary weight strapped to the front end of the crankshaft.

Installing LW parts onto the rotational assembly of the motor for performance gains are not new. This has been around since people have been hot rodding cars. Things like underdrive pulleys and lightweight pulleys have been a big part of the performance must do’s. We all know the huge gains seen with adding an LW flywheel if you have a manual car. We have a huge TQ converter strapped to the back of our motors filled with several quarts of transmission fluid and since we obviously can’t remove that we now look to the front of the motor and the crank pulley.

Why would you want to remove and replace your crank pulley? Simple, if you want to see the science behind this go cut a piece of string just over 2 feet long. Then from there tie a 10lb weight to the end of that same string and see if you can swing that 10lb weight in front of you like a propeller of an airplane. If you even can swing it, try to keep it going at a constant speed, then after a few seconds try to swing it as fast as you can. It will take a large amount of effort to get the speed of the weight to accelerate. After you did this replace the 10lb weight with a 2lb weight and repeat. The results will be drastically different. You’ll be able to speed up and control the 2lb weight and its spinning speed much easier and with more acceleration on demand.

That’s the crappy roadside simplistic explanation. The physics behind rotational weight reduction are sound and impactful. The JHM LW crank pulley allows the motor to spin up faster and with less work. It allows for much less resistance in rotational acceleration of the motor RPM. This results in a much more eager throttle response out of the motors acceleration and its simple.

http://audirevolution.net/addons/albums/images/125978846.jpg

You’re dropping almost 9lbs off the front of the crankshaft.

So, for those of you who don’t know where this is or what it looks like. Let me show you.

Here are all the important things I reference where they’re located and what they look like.

http://audirevolution.net/addons/albums/images/522405473.jpg

You’re going to have to pull the front end of the car off to replace your crank pulley. While I was in there I decided to remove the SAI system. SAI stands for Secondary Air System. It’s the system that turns on in cold weather to help your cats heat up quicker. The downside is the car tends to run rougher on cold starts when it’s activated and over time people have seen terrible carbon build up in the SAI valves. So, for me, I just removed it. Keep in mind unless you have a JHM tune doing this would result in a CEL the first time the SAI system is required to turn on.

Back to the pulley install. For me, the JHM LW crank pulley was a no brainer. It’s like doing the intake spacers when you do the carbon clean. You’re going to be in there anyway, you might as well put in the spacers while you’re there.

I was replacing my OEM belt that looked to be original and also looking to service my belt tensioner. The belt tensioners like to freeze up over time so, I would pull off the belt, take off the tensioner and lube it. While I was in there I added the LW crank pulley.

http://audirevolution.net/addons/albums/images/137177550.jpg

The stock crank pulley is definitely heavy. Even if you don’t have to replace the belt it might not be a bad idea on replacing the crank pulley. The B6 and B7 S4’s had issues with these failing and the B8 S4s are known to have their crank pulleys fail.

As mentioned, while I was doing the maintenance I decided to remove my SAI system.

Here is a picture of all the other hardware removed. You can clearly see what lines are the SAI lines. They tap into the front of the cylinder heads.

http://audirevolution.net/addons/albums/images/280039249.jpg

You can’t just pull the SAI lines off and not cap them. Or you’ll have exaust gas coming out the front of your cylinder heads. So, I quickly cut and welded the ends off the SAI lines.

http://audirevolution.net/addons/albums/images/260811121.jpg

If anyone wants more pictures on the SAI removal let me know. I removed the pump and the valves that were located off to the side.

After the SAI lines were off and I made the caps I started putting everything back on again. Making sure to use Locktite on the crank bolts and using a nice white lithium lube on the belt tensioner.

http://audirevolution.net/addons/albums/images/60208689.jpg

The crank pulleys on the 4.2 S4 and S5 are just like our crank pulley on the 5.2. They are counter weighted and that’s something serious. The money in the pulleys is in the balancing of the pulleys to make sure they have the right counter weight.

Years and years ago when this came out for the 4.2 S4 a few people would try to make the argument that putting an LW pulley on would cause issues. Well, there been no issues with the 4.2 S4 or S5 after 10 years and after several motor teardowns for built motors in the 4.2 there was no sign of any bearing issues. As a matter of fact there seemed to be less bearing wear on cars with LW crank pulleys over OEM units.

For fun, I did a crude test to show there was no change in NVH. I did the oldschool water on the intake test.

1800rpm

http://audirevolution.net/addons/albums/images/993579728.jpg

3200rpm

http://audirevolution.net/addons/albums/images/144367236.jpg

from 3200 back to idle.

http://audirevolution.net/addons/albums/images/393403474.jpg

There are huge offset weight tolerances in the OEM pulleys where the JHM units are balanced with precision balancing. I actually noticed a smoother idle and lower knock voltages when crusing with the JHM LW pulley.

Very insightful, thanks cv. Keep it coming! Haven’t seen a good crank pulley explanation like that in awhile.

justincredible · December 8, 2019, 5:54pm

Great post. I like the picture heavy content. That was a good explination on rotational weight. The crank pulley is a nice add on to help the motor.

bigserve134 · December 8, 2019, 5:54pm

So what your saying is that I need that crank pulley for my S5!?

I was concerned that reducing the weight by so much is going to displace that force elsewhere…on some other rotating / moving part up or down the line. But what CV is saying that it is safe and in fact even better. Therefore that force/energy must being going to the wheels ;D!

justincredible · December 8, 2019, 5:54pm

You need a crank pulley for your S5. The stock crank pulley has a rubber diaphram inside that is there for hryomonic ballence. But due to the fact that the rubber diaphram is usually destryed on older crank pulleys people are not getting any use out of itanyways. That and in the V10 cars they have a huge fluid dampener on the car in the Tq converter so its kinda redundent. As for the S5 you have that huge flywheel that would absorb most of the vibration. The JHM crank pulleys are perfictly ballanced so you get no vibration from ballance issues.

bigserve134 · December 8, 2019, 5:54pm

justincredible:

bigserve134:

So what your saying is that I need that crank pulley for my S5!?

I was concerned that reducing the weight by so much is going to displace that force elsewhere…on some other rotating / moving part up or down the line. But what CV is saying that it is safe and in fact even better. Therefore that force/energy must being going to the wheels ;D!

You need a crank pulley for your S5. The stock crank pulley has a rubber diaphram inside that is there for hryomonic ballence. But due to the fact that the rubber diaphram is usually destryed on older crank pulleys people are not getting any use out of itanyways. That and in the V10 cars they have a huge fluid dampener on the car in the Tq converter so its kinda redundent. As for the S5 you have that huge flywheel that would absorb most of the vibration. The JHM crank pulleys are perfictly ballanced so you get no vibration from ballance issues.

Really? Going to IM you a few questions so that this thread does not get derailed. Thanks!

jc_io · December 8, 2019, 5:54pm

Great writeup! Bookmarked to read soon!

v8a6 · December 8, 2019, 5:54pm

Fantastic addition to the site!

Where would the v10 S6/S8 community be without posts like this???

JRach · December 8, 2019, 5:55pm

So how about some 1/4 mile times from the fastest N/A Audi V10 sedan in existence?!?!

buddyboy · December 8, 2019, 5:55pm

when you say front end needs to be removed to replace the pulley, do you mean just the bumper? Or is their other parts in the way behind that that need to be removed? I would be interested in the crank pulley and changing the belt too while there. That belt is just the ancillary drive belt i guess and these v10’s have a timing chain?

i think i need to do carbon clean, IM spacers and this LW pulley

justincredible · December 8, 2019, 5:55pm

To do the crank pulley you need to remove the bumper and front core support. Its not too bad of a job. The core support us just behind the bumper it holds the ac condencer and the raidator. Its a great time to flush the coolant.

It makes getting the pulley and the accesory belt on much eaiser.

The Alternator is run off the belt that runs off the crank. The AC and the powersteering are driven off the back of the motor on the timing system.

If you want I can make a post showing how most of that stuff works but it will be on a 4.2 V8 as they are the exact same less two cylinders.

CountVohn · December 8, 2019, 5:55pm

Yes, you need a crank pulley for your S5

Thank you. I have more coming.

Thanks, If you guys don’t see something that you would like to know about please feel free to ask or post. Keep an eye out for more

Thank you. I think the real question here is, where would the S6/S8 be without out you?

You’re so right. I know, I will speed this along so I can get to that part. Sorry for the gap in posts. When you don’t see posting on my part I am making headway… Or I’m trying to, I promise.

Buddyboy, yes the bumper and core support need to come off as Justin mentioned. While it is an extra step, if you’re doing a carbon clean or full maintenance it’s a great time to pull the front end off to do the accessory belt the coolant flush the crank pulley and with the front end off the carbon clean and spacer install, is a bit easier to do as well.

CountVohn · December 8, 2019, 5:55pm

GIVE ME A BRAKE… Next phase in the performance journey, was to replace my squeaking worn out brakes.

There are several options when it comes to just replacing the OEM rotors. For me, I’ve seen lots of guys go the cheap option and you get what you pay for. Cheap rotors tend to use cheap material that wears out quicker and doesn’t seem to offset the cost in the long run.

For me, I really want to bring out the supercar in my super car. So, the search for performance rotors started and as usual as most of you know there was nothing. So, I called the guys at JHM and asked what they could do. They have performance rotors for just about every other platform why not us. The S8 and S6 front rotors are the same on our cars so its like one big market.

I wanted a lighter more performance oriented rotor that would help drop some rotational weight while pulling out the heat and helping with pad life. Heck, if the Lambo gets performance rotors, that dissipate heat and weigh less, why don’t we right?

http://audirevolution.net/addons/albums/images/254154009.jpg

BOOM I saved 30lbs of not just weight but rotational weight. That’s a 15lb weight reduction EACH SIDE, while adding a huge drop in breaking temps. That’s more than some light weight rims offer and at a fraction of the cost of lightweight rims.

The added great part is way-way down the line when it comes time to replace the rotors again, you just need to order the rings. Ording the rings will save you quite a bit of money. The rotors cost a bit more due to being two piece and being that their performance rotors. Being two piece has several advantages if you really want to track the S6 you can just get an extra set of rings for the track like lots of the road race guys like to do.

I’m not a huge cosmetic guy but even these OEM rotors look underwhelming.

http://audirevolution.net/addons/albums/images/759630630.jpg

The other thing l didn’t like about the stock rotors was the fact that the rotor was just a little bigger than the pad surface needed to be. So, this resulted in my rotor having a huge lip on it from where the pads had worn away the material. It made getting the heavy OEM rotors out quite a chore.

Now putting on the JHM rotors. Very easy a straight forward job. The addition of the slotted feature that comes with the JHM rotors is not just great to help in braking performance, but I think it looks nice as well.

http://audirevolution.net/addons/albums/images/650999356.jpg

To me, it’s hard to beat adding performance while doing maintenance. Nothing is real exciting about doing a brake job, except when you know you’re dropping weight, adding performance and helping make things look just a little better at the same time. It’s a win win win.

vtgt · December 8, 2019, 5:55pm

Brakes look great CV! What brake fluid and pads are you using?

MDUBZ · December 8, 2019, 5:55pm

That was a fun night hanging out and getting those brakes fitted CV. Don’t forget to mention the trick to getting the rear caliper brake pistons loosened up enough to fit over the rotors

v8a6 · December 8, 2019, 5:55pm

That is crazy! A 15 pound weight saving per rotor is huge!

So awesome!!!

c.scott · December 8, 2019, 5:56pm

Holy hell, that’s a MASSIVE rotational weight savings!! I just might need to have JHM address that on my car as well, in the coming weeks. I have no idea what my current rotors are, but all 4 are slotted which I don’t think is stock. EBC maybe? not really sure.

buddyboy · December 8, 2019, 5:56pm

What kind of of price range are we looking at for the two piece rotors? I need to do my rears soon but could do fronts as well. Shipping would be a killer to me though in Ireland

Jake · December 8, 2019, 5:56pm

Those rotors will be available soon on our website. However if anyone wants them pre-release give me a shout!

Jake · December 8, 2019, 5:56pm

Oh by the way… 38lbs for a used worn out rotor. I weighed in a new rotor at 39lbs ;D

c.scott · December 8, 2019, 5:56pm

Price? My car’s heading over to you guys in a couple weeks, if they don’t cost a fortune I’d be happy to give 'em a go!

Edit: after a quick google search, it appears that I’ve got EBC GD Sport rotors on all 4 corners currently. If I understand correctly, these are crap. So I’d definitely be ok with an upgrade.