B8.5 Port & Polish

B8 S4
#1

Had my s4 in for a service appt today and ran into another forum member that I had met before from AZ. Long and short is that he has a B8.5 and had a local shop take the supercharger off for powder coating. While off the shop gave him a deal on porting and polishing in prep for some tuning he is having them do in the next month or so. I didnt have a chance to get a lot of details, but he was saying they saw a little over 20hp increase. No tune yet, but the shop did already mount a smaller pulley.

He said he has pics and details of all the work done and will be doing a write up for posting in the forums in the next couple weeks when he gets a chance. Hopefully he has before and after dyno logs from the shops mustang dyno as well.

Sorry for the tease of a post, but I thought it was interesting. I invited him over here to post the info just in case he isn’t already so hopefully more details and pics will be forthcoming.

#2

Tell him next time he has his SC removed perhaps consider direct injection Meth into each intake port?

#3

Good point. The Emola charger did looked pretty cool in person. The color alone would be worth a couple HP on some forums. ;D

#4

Do you have any pictures? That would be cool to see.

#5

Unfortunately I didn’t take any myself, but I found this on the shops facebook page of his car…

https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xfa1/v/t1.0-9/995609_365173756968182_56847036694108694_n.jpg?oh=779708496fe8486e6ae1a45025085d6a&oe=54CBC57C&gda=1419665815_999550dc613d99d2f3554c133e5d5403

Here is what they said about it…

IAP Racing LLC The S4 put down 272AWHP in stock configuration. The only modification it had was that we ported the supercharger. We are doing tuning and dyno pulls through this entire build. To document how much hp each modification truly makes. Keep in mind this is a true load bearing Mustang Dyno that reads much lower than a standard dynojet. The Audi S4 has a pretty high percentage of valve train loss. Somewhere around 28%. So that would translate the 272AWHP to 348 horsepower at the crankshaft. Not too bad for just porting the blower. The real advantages of porting the blower will be more evident as we are increasing fuel, timing, boost, etc. Stay tuned for more updates.

https://www.facebook.com/iapracingllc

Jimmy,

I don’t think you made it out with us, but its the place in sterling that a bunch of us rolled into for their open house a couple months back.

#6

I heard about that but couldn’t make it because of work.

Interesting, they are right down the street from the detailing place that Josh with the R8 recommends.

The yellow SC does look good on that car.

#7

Sounds like they put down 272whp with the post, do you know if they did a stock dyno?

#8

they said it gained 20 hp doing the port and polish…so that means this car dynod around 250-255 whp stock? They don’t seem to have actually dyno’d it stock (or they’d have posted the numbers)…so where did they get the 20 hp claim from porting/polishing? Was that something they invented to justify the money the guy had just paid them?

[quote]The Audi S4 has a pretty high percentage of valve train loss. Somewhere around 28%. So that would translate the 272AWHP to 348 horsepower at the crankshaft. Not too bad for just porting the blower.
[/quote]
WTF are they talking about now?

  1. 272 whp does not translate to 348 hp with 28% drivetrain loss. If it was 28% drivetrain LOSS (key word loss…not gain as they have calculated it) the car would be making more like 377 hp at the crank (28% lost = 0.72 x 377 crank = 272 whp)

  2. why are they saying not too bad for porting the blower…??? this is perhaps the LOWEST EVER dyno figure for a B8 or B8.5 S4…and they’re claiming it as a victory, with their modification?

I have literally never seen a stock 3.0T S4 dyno lower than 275 whp. So they’re definitely confused about something. Of course maybe their dyno is the toughest setup dyno ever…great. How are they anticipating stock crank hp then if they’re using an outlier dyno?

We have already seen that the B8 3.0T S4s make around 355-360 hp at the crank, stock, when run on good fuel in decent conditions. These guys are just straight up confusing.

#9

They are bad at math…lol

…and have a speical dyno that is lower than the rest.

#10

Using stock for a comparison in this test is not the best because several items are modeled based on the factory setup. For example, let’s assume you were to remove a restriction which ended up causing boost pressure to drop, but mass airflow to increase. The ECU will not know mass airflow has increased, because it’s modeled based on the factory setup. It will assume it has dropped. The ECU will actually see less boost pressure than expected, and as such, will likely close the bypass valve a little more to get back to where it should be and satisfy all the models. Then the ECU will think everything is running as it should stock, but in reality it’s not. In such case, power can go up.

The best setup would be to do this on a tuned engine where the bypass valve is closed the entire time. It would be interesting to see if it picks up any power just with the modification alone. Then, from there, the tuner can see if they can pick up any more power if it leads to achieving more ignition advance.

#11

The point is they are claiming a 20hp gain over stock from their backwards calculated numbers that aren’t even correct.

If they want to compare to stock , they should have a stock baseline of that exact car.

I think most of us understand the tuning aspect and the issue with the stock tuned ECU taking advantage of the increased/more efficient air flow, but that really has nothing to do with what this company is trying to portray in order to sell/perform these modifications.

#12

So I just read over everything again and the shop didn’t say 20hp increase the owner did. maybe they took their estimated crank and subtracted the cars stock rating to get the 20hp they told the customer? did that make sense?