V/Stacks are on ! - The Unofficial BMW M5 Messageboard (m5board.com)

Keith97M3turbo · 11th January 2004, 06:03

Well I couldn't wait for dyno time to come up.I had to put them on secretly while the wife ran some errands this morning. After driveing with the butt dyno today it seems like the bottom is alittle softer but the 4.5-5k and up pulls harder. Reminder this is ONLY after todays impression.
I am set up to do some dyno testing with stock stacks vs. Technik stacks very soon , as I'm curious to see what gives? (and if the butt dyno is calibrated correctly)

I will post dyno info hopefully in a week or two,as I still have to get the metal cats put on mon/wed-ish.
If wondering, they are from Sam@Rennsport.
Here's a pic. but I think we've all seen them before,they all look the same.

MIB · 11th January 2004, 09:24

Hey Keith,

Congrats on the stacks. I have them as well.

I think they will heat soak in Drag and Dyno applications.

Because they are metal, they get hot when they sit.

When we installed mine, we put one in place and walked away for 5 minutes, and when we returned, it was so hot, you couldn't touch it. The plastic ones were hot, but not like the aluminum ones.

So what I have noticed is, the car feels really strong on the street, constant driving.

But at the drags where you drive 1/4 then park and heat up, it doesn't seem to pull as hard.

So if you want to see a true dyno effect, park the car and let it get cold first.

Then do the dyno run, with cold trumpets. Driving along there is plenty of air flow to keep them cool.

Good luck and let us know about the dynop results.

11th January 2004, 18:00

They sure look great!

tampa_M5 · 13th January 2004, 04:25

yes those really do look great, and i would be interested to know how much hp they actually add.....and did you get those from Renn-Sport???

-----Jonathan

Keith97M3turbo · 13th January 2004, 06:04

Jonathan, yes they are from Sam at Rennsport.
I will be doing some dyno tests with the stacks very soon and will post results, Sam is expecting my findings. I'm also curious to see what power the car is makeing with all the current mods.

Terk · 13th January 2004, 06:13

Very nice, they look excellent. It's really too bad the plenum cover has to hide such art.

Regards,

Terk.

gra8fuldd ed · 13th January 2004, 06:14

Quote:

Originally Posted by Keith97M3turbo

Jonathan, yes they are from Sam at Rennsport.
I will be doing some dyno tests with the stacks very soon and will post results, Sam is expecting my findings. I'm also curious to see what power the car is makeing with all the current mods.

Keith:

Have you done some Dyno Testing in the past ... prior to any Mods ... in order to establish a good baseline?

If so ... Could you post some numbers?

I am sure it will be nearly impossible to tell how much, if any, increase in HP the shorten VS will yield. From everything that I've read & heard ... The shorter the VS will bogg down the low end and increase the top end of the power curve.

I guess that's a good thing ... IF you plan on going IN X S of a 120mph!

Are you plannning on lower or changing your differential? If so ... to what?

Keith97M3turbo · 13th January 2004, 06:35

Ed, I didn't get to do any base dyno runs as the car had mufflers and filters on it. I was wanting to see how the car faired with all the stuff in my sig.,but mostly see how the headers(and after the metal cats on weds.) turn out.
I need to dyno with stock runners and then v/stacks to see what the outcome is so I can let Sam know. So then I guess we all know if they work or not.

Why I didn't dyno first.Mmm,well..I bought the car in late this past Oct. and told myself and others "I'm not going to do anything to this one"

I did believe it! for a minute. Well all of a sudden BAM!! next thing I know stuff is being ordered and being sent to secret locations,not the house caus' that's where the wife is and she was one of the ones that heard what I said.
If she knew that would be bad. It all happened so fast I didn't have time to dyno it.
This was supposed to stay 'civil and stock' because the m3 got a little, no alot out of control.
As for a diff.,very funny you mention I was actually thinking of doing the Evo or Dinan 3.45's (a mod the wife can't tell).

gra8fuldd ed · 13th January 2004, 06:46

It's really too bad you didn't get the chance to Dyno in order to baseline YOUR specific beast. The stock or even slightly modified M5 is all over the dyno HP range from as low as 310hp to as high 360hp and those were BOTH completely stock '03 M5's.

My baseline before any mods was 342hp on a 70 degree day at sea level. I really did not think that was very good. Now I have lots of mods and it's time to go back to the dyno and see what has developed before I install Headers.