Project S5 Starts.... Now.

A5/S5/RS5
#1

As usual with the N/A Audi game most of you are told there is little that you can do to have solid results power wise.

This thread and this entire list of parts is looking to Once again smash the old way of thinking. Project S5 is here to do the same thing thats been done in the past with the successful land of N/A development.

http://audirevolution.net/addons/albums/images/334472187.jpg

Over the next few months your going to see a transformation of this S5 from stock to a fully N/A built monster. Just like the other N/A cars that have been built. The combination is going to be. Exhaust. Starting with headers. After looking at the S5 its clear there have been lots of compromises made in both the exhaust and the support system. This post will expose all of them.

So while I’m not a fan of the dyno. I can see large interest in the same dyno same day usage. As we move forward the formula that worked for the B6 and B7 S4 is going to be used on the S5. Most people might not know but power wise the two cars are very close power wise.

Here is a dyno of to cars. A B7 S4 and a S5. Same day same dyno.

First is a S5 with cat-back exhaust.

http://audirevolution.net/addons/albums/images/163906876.jpg

Now is a B7 S4 with the same mods.

http://audirevolution.net/addons/albums/images/578664411.jpg

The difference.

B7 S4. max hp 294. Max Tq. 294
08 S5. max hp 294. Max Tq 282.

We can safely conclude that the stratmosphere hot air intake cost or LOST the S5 TQ. None of the gimmick hot air intakes work on these Audi’s. The Stratmosphere hot air intakes have been robbing people of money and power for years. So if you take that out of the equation. The cars made about the same figures all around. That sets the stage for the formula used on the B6/7 S4’s to work on the S5. Now there is going to have to be some changes made for obvious reasons. Still The S5 should see the same or close to the same results.

The first power mod on the S5 is going to be the exhaust. Ending up with a set of headers. The headers have been a big power adder to the B6/7 S4.

Here is a before and after on a Automatic B7 S4. Keep in mind that manual cars have seen better results.

http://audirevolution.net/addons/albums/images/94103426.jpg

Stock S4. max Hp. 241. max Tq 224
header S4 max Hp. 261. max Tq 262

Thats a gain of 20whp and almost 40wtq for a large part of the rev-range. What is important to note is how the Tq came in so much sooner with the headers and then was able to carry for so long.

So now that we have all that out of the way. Lets look at what the S5 has going on exhaust wise Stock.

#2

The stock exhaust on the S5 really has its issues. The PreCats are huge, The main cats look to be smaller then past Audi offerings. This combination seems to be there to address the dreaded PreCat back flow issue. On the older cars the PreCats in the exhaust never seemed to flow enough. Due to the fact that the PreCat is only there for the first two minutes of the start up and warm up cycle it always ended up doing more damage to performance then good for emissions. Infact the main cats alone are more then enough on the older Audi’s to help you pass emissions.

When you follow the exhaust back you can see now that what used to be the main cat is now a smaller version. While you would think this is a good thing. Its not. The fact that the older main cat or second set of cats were so much larger played a large roll in not being a restriction to the exhaust.

http://audirevolution.net/addons/albums/images/383245291.jpg

Also in the picture you can see how the exhaust takes a series of turns and bends. This is just flat out bad for performance.

Think about it like this. You have 3 90deg bends and then 3 30deg bends. There are more then that in this exhaust but when you add up the amount of bends I listed you just had your exhaust go threw a full 360deg. Buy the time the exhaust exists the pipes it will have done a full circle of useless flow. The goal is straight in and straight out. You want slow bends and if your making a X pipe you have to watch your angles and placement. Its not easy.

here is a quick walk around of the exhaust on the S5

http://audirevolution.net/videos/68/s5-exhaust

#3

Wow, great stuff and glad to see this platform begin to truly be developed as the S4 was a couple years back with JHM.

I’m also anxiously looking forward to some real pics of what went on when those pics were taken. I seem to recall seeing that lift in the past. . . Magical stuff happens when cars go on that lift. . . !

#4

wish I could have been there to lend a hand, maybe on the reinstall

#5

This is great news. Im very excited please keep us updated on this. I would love to see more.

#6

I gotta say if I could just pick one audi for my DD it would be an S5, such a good looking car! That car would then promptly get sent off to JHM :stuck_out_tongue:

Looking forward to see how things progress with it, I would assume it will take a similar path to the B6/B7 S4’s? I think a thread referenced the differences in the engines but I can’t find it.

#7

^ I said 6 months ago, if I had the cash I would just buy a S5 and send it to JHM for 6 month and let them do whatever they wanted with it. I know it’d be the best investment I could ever make to let them have full reign on a car like that for an extended period of time.

I’m just glad to see there are some S5 owners local to them that can help begin some beta testing for them. I know one or two down in my part of town that would love to have some real tuning help, but we’re not near JHM at all so it makes it tough.

#8

Before we get to far along in the project. Lets took at some of the possible down falls in the S5 design.

One of the added pieces that has a large amount of interest to me is the air box. While there still needs to be some investigation into this and the changes that can be made. It has started off looking like the S5’s air box has some odd twists.

we all know what the air box looks like. The S5 has a large runner going into the air box. I didn’t get all the measurements from the box yet but it seems a little on the small side. Not that this is something we need to worry about yet. We should wait for the math to come back on that.

http://audirevolution.net/addons/albums/images/804448090.jpg

You can see here the standard inlet coming from the front of the car into the air box. The opening on the air box is much larger then Ive seen in the past. So there is a large amount of open space for the car to pull in the front fed air.

http://audirevolution.net/addons/albums/images/748366352.jpg

When you look further you can see that the air box also much like the RS4 and the S4 has another feed source at the bottom that is controlled by a vacuum actuated valve.

This picture is at the bottom of the air box. Its in a great location. As its located in a spot to only pick up cold air.

http://audirevolution.net/addons/albums/images/355400172.jpg

Here is another image with the scoop on the bottom for reference. While the scoop isn’t very large. You might see a gain by just removing the scoop. As the scoop seems to be more of a restriction in its design. Also the scoop is picking up cold air but its not being force fed the air. There isn’t a clear path for the scoop but it is located in a spot that will get plenty of cold air.

Notice the scoop at the bottom of the air box as its attached in this picture.

http://audirevolution.net/addons/albums/images/868578191.jpg

Now what you will notice is that there isn’t the same opening in the air box that the other cars have for slowing down the air flow. This is the part of the air box that generally in the past would connect to the fender wall and air would be introduced into the incoming air stream to slow down the air.

While the S5 isn’t going to be effected by that air reducer it has something possibly different that might be the source of a very power robbing restriction. There is one more spot where the S5 is able to get more air from but it might not be too good.

http://audirevolution.net/addons/albums/images/441533246.jpg

This opening is getting fed directly off of the exhaust manifold. Here is a better picture showing just how bad it is.

http://audirevolution.net/addons/albums/images/218535692.jpg

While it might be a bit premature to assume that this is there to rob power. Pulling in hot air isn’t exactly the formula for great power. At this time I have to do a little more research to fond out why its there. Based off what we have seen Audi do in the past. It would lead me to believe that this is there to effect air flow, but at what pre set limit or at what point do they want this activated.

That might be the bigger question. Still at this point in time I would suggest closing this off to the air box to stop the hot air from getting in the fresh air stream going into the motor.

Thats all for tonight kids lots more coming.

#9

could that little hot air intake piece be there for emissions? like the throttle body heater on the S4s. Isn’t hotter motor = cleaner exhaust?

#10

After starting my carbon clean I found that we in the S5 world have the throttle body heater. Would think make the idea any less plausable that this would be for emmisions?

#11

^TB heater is a pretty common part (and you could probably adapt the JHM TB heater bypass to your car if you wanted to), I wouldn’t be surprised if the open duct is still to heat the air up for emissions.

#12

SO after looking at the airbox and stuff. It was time to get into the serious parts. We started making the new catback and then getting the car ready for the Headers.

Now the post wouldn’t be all that exciting if I just posted up pictures of the cat back and headers now. So your going to have to wait on that.

So on goes the project. We started getting the car set to pull off the front clip.

http://audirevolution.net/addons/albums/images/334472187.jpg

From there we took off the bumper removed the head lights and started to move the font end stuff out of the way.

http://audirevolution.net/addons/albums/images/481735656.jpg

It was a pleasant change to not have the Aux rads to deal with. The S5 has a very large radiator system. The front end of the car was well laid out and made for a easy removal of the bumper and the rest of the wires.

http://audirevolution.net/addons/albums/images/170506715.jpg

Everywhere you look you can see the advancements that Audi took on the S5 compared to the older S4. ON the S4 the tensioners for the belts are known to fail when you mention them. Look at the spring loaded unit the S5 has. While there are plenty of great new additions there are also a few down side changes.

The water pump is now plastic. Not sure how I feel about that. The older S4 water pump was quite strong. Not to say the S5 water pump isn’t up to the task, how ever if you think about it one of the first things to fail on the New S4 is the water pump. So that is something to think about.

One more step down memory lane is the space saving use of the counter balanced crank. Thats right the crank pulley on the S4 and now the S5 is very very unique to the car. They each have a counter balanced crank pulley for the motors. Knowing the money that was spend on the S4 to make the crank pulley. The S5 crank pulley is also going to cost a pretty penny to get made.

http://audirevolution.net/addons/albums/images/146547785.jpg

Getting closer to pulling the motor you start to see how many new emissions changes and new hoses and lines are added. It quickly can over whelm you if you don’t know where they all go or what there all there for.
Even the intermediate fire wall is clogged with new things.

http://audirevolution.net/addons/albums/images/601708990.jpg

The S5 is all business when it comes to space and weight savings. Audi went to the extreme on this car to make sure the motor was set back far enough to not cause the car to be nose heavy. Even the windshield wiper fluid container was moved further back

Honestly there was plenty of room for this up front where it is usually found. When you really look at what Audi was trying to do, they did it.

http://audirevolution.net/addons/albums/images/216776468.jpg

After you take out all the emissions components you can really see how clean the layout is. Sticking with the Audi weight distribution theme Audi actually moved the motor as far back as they could and moved the motor about 4" towards the passenger side to help off set the driver weight in hopes of creating a better balanced car.

http://audirevolution.net/addons/albums/images/24491113.jpg

These changes might look like a lot but they pail in comparison to what comes next. Audi went almost too far when it comes to trying to get the benefit of the quattro drivetrain and a solid balance to the car

#13

Que the crazy clutch design post lol… nice update

#14

Wow, love the update! Looking forward to seeing this continue to unfold and reveal it’s secrets. Also very interesting to see all the changes made and no AUX Radiators must be amazing! I’m surprised they didn’t take bigger advantage of that with the intake (from what it appears at least). God I want a JHM S/C S5. . . .

#15

Just thought I’d bump this after a month as it seems the S5 section has gone quiet. I really love the S5 platform and am interested to see what is being properly developed for it. Any update or potential ideas you’re able to throw out there is always appreciated. Thanks.

#16

Sorry guys Ive been working more on the car then this thread. We are going to have a few weeks down time while we wait for odds and ends parts so I thought I would start to get you all up to speed. Ill make a post on this later tonight

#17

Thumbs up!

#18

Last time we left off with the motor about to get removed.

http://audirevolution.net/addons/albums/images/24491113.jpg

The S5 had definitely had some engineering put into it. This is at every turn and bend you go, you see it.

The always pack these motors in there tight. Making headers isn’t going to be easy.

http://audirevolution.net/addons/albums/images/146547785.jpg

When you pull the motor down you can see how tight everything is to the block and transmission. Look at how big this Precat is. Its almost as big as the main cat. When you look back the Audi 3.0 had one large cat that did a good job, this cat looks almost as big as the 3.0 cat.

http://audirevolution.net/addons/albums/images/958195694.jpg

When you start looking closer and closer, you can see where Audi really made efforts to make the car better all around. You can see that the power-steering has been moved to make for a better ride and that the motor has been moved back to change the weight distribution

http://audirevolution.net/addons/albums/images/120730921.jpg

The more you dig the more you find. When we saw this, we were blown away. We had seen nothing like this before in automotive engineering.

http://audirevolution.net/addons/albums/images/538841914.jpg

At first glance it doesn’t look like much. Till you dig a little further

http://audirevolution.net/addons/albums/images/417076517.jpg

Its at this point you realize just how crazy this car is and how hard things are going to be.

http://audirevolution.net/addons/albums/images/699688396.jpg

The actual flywheel has to be moved off the motor to make room for the 1/2 shaft to run. 99.9% of all clutch and flywheels sit directly on the back of the crank shaft. I’ve never seen a flywheel that has been moved back to avoid the 1/2 shaft.

Audi moved back the motor in an attempt to get the motor to sit further back. This helps center ballence in the car and makes for a better handling car. The only issue here is the S5 clutch and flywheel needed to be moved off the back of the motor to make room.

#19

Strange stuff, I suppose the B8 S4 is the same way

#20

how much shorter length wise is the V6 in the S4 compared to the V8 S5?