Quote:
Originally Posted by Rotzy
Thanks for the feedback pits200 CT335xi. I must say I'm really surprised that no one is worried about adding 140+ hp to a stock N63TU.
Yes, that is true about my dyno numbers. I was being conservative when I said 140+ at the crank. I definitely wouldn't be beating on it non stop, but I have seen 15psi of boost during moderately heavy accelleration (not to the floor) on the highway. I'm thinking that if a flash allowed, say, 20psi, you wouldn't have to be beating on it to see those boost levels and the added engine stress that comes with it. I guess I'm just being overly conservative with this notoriously troublesome engine.
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To add to this, there are a few dynos from N63tu tuners. If you look at Mission Performance dynos for their tune, the baseline for a 550i was 393rwhp and the stage 1 puts down 464 for a 71rwhp net.
I have seen other n63tu dynos as well and the consensus seems to be around 390rwhp, which if you do the math (15% drive train loss on a rwd vehicle) puts it at 458 crack. This is right in line with typical BMW under claiming actual HP.
The dyno BPC is showing at the net +127 claim seems a bit odd. I am not sure what vehicle they were running but it only did 350rwhp stock, far less than the 550i in the other example. Still using a dynojet, this would be only 409 crank under the same math assumptions. That crank number looks like the old n63 number to me and far less than factory. Even Terry @ BMS dynoed a stock 550i and it was 392.
So it makes you wonder whose claims are right. To be fair, DusH did all wheel dyno his 50i and it made 455 or something on a hot day and it was a mustang dyno which said typically reads 20hp lower than a dynojet. That would put it right into the 470awhp area. Again, this is in line with the other plots and even BPCs high number.
To me, that stock number BPC has is suspect. I think the REAL net wheel hp is somewhere around 70-75 with a stage 1 tune. This is far from aggressive for a BMW engine IMO. A stage 1 tune on my old 335i netted around the same on a dyno and that engine and platform handled it fine for years.
Hope that helps.