Subtraction by Addition: CHECK! Sometimes I hate my car - Page 2 - The Unofficial BMW M5 Messageboard (m5board.com)

Diny · 4th July 2009, 03:27

Quote:

Originally Posted by jrhaile

Yes I did... I did 326whp 2 months ago. Not to be an ***, but did you read my first post or was I unclear? Because I'll correct it if needed

I meant before you added the first set of mods. With the new mods, you lost 5hp and gained 8 lb/ft of torque. That's about 1% difference in horsepower and less than 2% increase of torque. I think the same car can see that kind of discrepancy on different days of the week.

I understand your concern, though, and I'll stick to this thread to see where it goes.

I must echo the thought that you shouldnt lose sleep over this (after all, wouldn't you sacrifice 5hp for a better sounding car? I would!).

jrhaile · 4th July 2009, 03:28

I called up a race car/exhaust specialist here in town who does nothing but mandrel bends and full race exhausts with SS piping. Going to take it in to him and see what he thinks about the system and see if there is something possibly hindering me.

jrhaile · 4th July 2009, 03:30

Quote:

Originally Posted by Diny

I meant before you added the first set of mods. With the new mods, you lost 5hp and gained 8 lb/ft of torque. That's about 1% difference in horsepower and less than 2% increase of torque. I think the same car can see that kind of discrepancy on different days of the week.

No, I got the car with the Dinan S1 tune and Intakes. I added the Magnaflow and then dynoed the 326whp.

After that, I added the cats, tune, etc and just dynoed 321 today.

jrhaile · 4th July 2009, 03:31

Quote:

Originally Posted by blackxs

The temperature difference between 2 months ago, late spring, and now, summer, would probably be enough to give that 5hp difference.

If not, I would blame lack of backpressure in the exhaust system from your new exhaust setup and the tune could be less than ideal.

If you dynoed them back to back, making sure the temperatures were the same, I would blame the mods. But from the sounds of it the temperature variance is to blame.

Correct me please if I'm wrong, but shouldn't the dyno correct for tempature since it's SAE?

jrhaile · 4th July 2009, 03:32

Quote:

Originally Posted by Diny

I meant before you added the first set of mods. With the new mods, you lost 5hp and gained 8 lb/ft of torque. That's about 1% difference in horsepower and less than 2% increase of torque. I think the same car can see that kind of discrepancy on different days of the week.

I understand your concern, though, and I'll stick to this thread to see where it goes.

I must echo the thought that you shouldnt lose sleep over this (after all, wouldn't you sacrifice 5hp for a better sounding car? I would!).

5whp for a better sounding car? Nope, never. I race my car, hard so I need all the horsepower I can get because this thing IS NOT LIGHT.

Diny · 4th July 2009, 03:34

Quote:

Originally Posted by jrhaile

5whp for a better sounding car? Nope, never. I race my car, hard so I need all the horsepower I can get because this thing IS NOT LIGHT.

But you lost a lot of weight by getting rid of the stock mufflers and resonators...

jrhaile · 4th July 2009, 03:41

Quote:

Originally Posted by Diny

But you lost a lot of weight by getting rid of the stock mufflers and resonators...

Point taken

jrhaile · 4th July 2009, 03:43

Dyno sheets in a couple of minutes...

jrhaile · 4th July 2009, 03:46

Crap I just realized that he put the wrong run on my graph from today... oh well you still get the point. The one with 326whp and 330ftlbs is from the last session back in May.

jrhaile · 4th July 2009, 03:57

Uploading dyno video right now... hopefully it's done before I have to leave in 30 minutes.