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      07-02-2014, 10:14 AM   #199
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Quote:
Originally Posted by CanAutM3
Quote:
Originally Posted by jc05e46m3 View Post
I would like to suggest that even is the wheel torque is "ficticious", it's still a number that can be used to compare gains/differences between different vehicles. Sure, not all vehicles will have the same losses, but I think the Wtq number is still a good data point to have.
Nope, "Wtq" as a single number is utterly useless.

I agree that looking at the shape of the "Wtq" curve can give an idea of the character of an engine. But one cannot compare different vehicles' performance relative to each other looking at "Wtq" curves only.
I never said as a single number? I'm saying it's not useless.
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      07-02-2014, 10:36 AM   #200
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Originally Posted by Sedan_Clan View Post
At least you didn't sip your final tablespoon of gas while waiting in a McDonald's drive thru for a bacon & egg biscuit on a rainy morning, and need the help of 4 Hispanic dudes to push your M3 into a parking spot (..while the gf brought you a gallon of gas). So funny and embarrassing.



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      07-02-2014, 01:33 PM   #201
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Has the bolt pattern changed from E90 to F80? I just happen to have 12mms and 15mms on my about-to-be traded E90...
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      07-02-2014, 02:03 PM   #202
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Quote:
Originally Posted by smedin View Post
Has the bolt pattern changed from E90 to F80? I just happen to have 12mms and 15mms on my about-to-be traded E90...
Bolt pattern hasn't changed, but F-chassis use a 14mm bolt instead of 12mm.

We have the proper extended length studs in stock and can set you up.
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      07-02-2014, 02:17 PM   #203
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Originally Posted by tom @ eas View Post
Bolt pattern hasn't changed, but F-chassis use a 14mm bolt instead of 12mm.

We have the proper extended length studs in stock and can set you up.
Might seems like a stupid question, but are my E92 spacers compatible with the F8X?

If they are, I will hang on to them when selling the car .
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      07-02-2014, 02:21 PM   #204
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Quote:
Originally Posted by CanAutM3 View Post
Might seems like a stupid question, but are my E92 spacers compatible with the F8X?

If they are, I will hang on to them when selling the car .
Spacers are, but you need new bolts.
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      07-02-2014, 03:16 PM   #205
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Quote:
Originally Posted by tom @ eas View Post
Spacers are.
Thanks

Quote:
Originally Posted by tom @ eas View Post
but you need new bolts.
That I had figured
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      07-02-2014, 04:16 PM   #206
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Quote:
Originally Posted by tom @ eas View Post
Bolt pattern hasn't changed, but F-chassis use a 14mm bolt instead of 12mm.

We have the proper extended length studs in stock and can set you up.
Would I be able to use my BC Forged 20x9 15mm front 20x10.5 25mm rear wheels from my E92 on the F82?
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      07-02-2014, 04:27 PM   #207
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Originally Posted by Buddy Revell View Post
Would I be able to use my BC Forged 20x9 15mm front 20x10.5 25mm rear wheels from my E92 on the F82?
Depending on tire sizes, we'll need to play around with spacers to fine-tune.
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      07-02-2014, 04:31 PM   #208
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Originally Posted by modkrazy View Post
Well, EAS uses an ego-boosting dyno, as they always seem to read quite high compared to pretty much everyone else. Even with 20-30whp less, though, still very impressive.
oh I see haha, that's interesting. Just saw the goodwood run of the m4 and wow did it look crazy...sounded awesome through the straight.
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      07-03-2014, 05:56 AM   #209
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looking very good.
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      07-03-2014, 08:14 AM   #210
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Quote:
Originally Posted by JoeFromPA View Post
CanAutM3 -

If the wheel hp is solid, and the calculation of wheel torque is a fixed calculation, then while it may be a fictitious reference it is a consistent reference that is comparable across models, correct?
My understanding:

The "Wtq" figure shown on chassis dyno charts is not torque at the wheels, it is an extrapolation of engine torque minus drivetrain losses (which is a number that does not exist IRL). I guess most people call it "wheel torque" because it is derived for the Whp number (power measure at the wheels). The real torque at the wheels is always multiplied by the drivetrain gearing, there is now way around this. Further, to really assess performance, you also need the wheel/tire diameter to establish the tractive force. The power number takes all this into consideration.

That being said, as was discussed at length in other threads, engine torque without gearing tells very little about a car's ultimate performance. It is much easier to simply look at the power curve from that perspective when comparing different cars. Looking at the shape of the torque curve does give a good impression of how the engine will feel (lazy low end pull or empty down low, linear delivery or peaky delivery, top end rush or running out of breath) but tells little about actual performance.

For example, comparing the S62 in the E39 M5 with S65 in the E9X M3. The S65 engine torque is much lower at 295lb-ft compared with the 369lb-ft of the S62. But when you factor gearing, it is a different story. In 6th gear (top gear), the M3 puts down a maximum 989lb-ft at the wheels compared to the M5's 964lb-ft. Just for comparison, the F8X will be putting down a whopping max 1189lb-ft in 6th .

Last edited by CanAutM3; 07-03-2014 at 04:46 PM..
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      07-03-2014, 09:15 AM   #211
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Quote:
Originally Posted by CanAutM3 View Post
My understanding:

The "Wtq" figure shown on chassis dyno charts is not torque at the wheels, it is an extrapolation of engine torque minus drivetrain losses (which is a number that does not exist IRL). I guess most people call it "wheel torque" because it is derived for the Whp number, power measure at the wheels. The real torque at the wheels is always multiplied by the drivetrain gearing, there is now way around this. Further, to really assess performance, you also need the wheel/tire diameter to establish the tractive force. The power number takes all this into consideration.

That being said, as was discussed at length in other threads, engine torque without gearing tells very little about a car's ultimate performance. It is much easier to simply look at the power curve from that perspective when comparing different cars. Looking at the shape of the torque curve does give a good impression of how the engine will feel (lazy low end pull or empty down low, linear delivery or peaky delivery, top end rush or lack of steam) but tells little about actual performance.

For example, comparing the S62 in the E39 M5 with S65 in the E9X M3. The S65 engine torque is much lower at 295lb-ft compared with the S62 at 369lb-ft. But when you factor gearing, it is a different story. In 6th gear (top gear), the M3 puts down a maximum 989lb-ft at the wheels compared to the M5's 964lb-ft. Just for comparison, the F8X will be putting down a whopping max 1189lb-ft in 6th .
well, to my understanding torque values are important. torque is what power is calculated from on a dyno, right? tq x rpm / 5250?

so, higher torque means higher power, therefore a lot of torque means a lot of power. stronger low RPM torque, and still holding strong tq (almost 300 to the wheels) at redline is a good recipe for strong power.

gearing helps some, sure, but there is no way that an e92 m3 feels strong whatsoever in 6th gear despite the shorter gearing. it may have short gearing, but it makes very low tq and at lower rpms, it just doesn't calculate to a lot of power. the e92 m3 spends almost half its rpms under 250 whp.
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      07-03-2014, 09:30 AM   #212
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Originally Posted by KennyPowers View Post
well, to my understanding torque values are important. torque is what power is calculated from on a dyno, right? tq x rpm / 5250?
Not on chassis inertia dyno.

Power is measured/calculated based on the ability of a powertrain to accelerate a rotating mass. The "Wtq" value is then derived from the formula you quoted (Wtq=Whp*5252/Engine RPM). Dividing by the wheel RPM would yield the true wheel torque value.

Quote:
Originally Posted by KennyPowers View Post
so, higher torque means higher power, therefore a lot of torque means a lot of power. stronger low RPM torque, and still holding strong tq (almost 300 to the wheels) at redline is a good recipe for strong power.
Torque at RPM is relevent to performance, hence power. But I agree, the more torque an engine is able to produce at a given RPM, the more power it makes at that RPM. But why bother looking at the torque value when the power tells the whole story .

Quote:
Originally Posted by KennyPowers View Post
gearing helps some, sure, but there is no way that an e92 m3 feels strong whatsoever in 6th gear despite the shorter gearing. it may have short gearing, but it makes very low tq and at lower rpms, it just doesn't calculate to a lot of power. the e92 m3 spends almost half its rpms under 250 whp.
My example of the E9X M3 vs E39 M5 was just to show how gearing is important when looking at torque figures; and JoeFromPA can relate to the M5 .

At 2000RPM in 6th, an E9X M3 makes more actual wheel torque than a 335i (~825lb-ft vs ~800lb-ft), yet 335i owners keep saying that the S65 lacks low end torque . Race an M3 and a 335i in 6th gear starting at 50mph and it will be pretty even at first and the M3 will eventually pull ahead. Sometimes it is a question of prespective, since the S65 pulls so much more when downshifting, it may feel week when kept in gear.

The more power an engine can make over a broad RPM band will translate to better performance. And that seems to be the strong suit of the new S55

Last edited by CanAutM3; 07-04-2014 at 07:22 AM..
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      07-05-2014, 06:20 PM   #213
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Is there any effect on warranty with the installation of Spacers?

Thanks
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      07-05-2014, 06:25 PM   #214
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Quote:
Originally Posted by 16M3
Is there any effect on warranty with the installation of Spacers?

Thanks
Warranty of?
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      07-05-2014, 06:48 PM   #215
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Originally Posted by 16M3 View Post
Is there any effect on warranty with the installation of Spacers?
Only of related items, like wheel bearings, but that would be very rare.
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      07-05-2014, 11:38 PM   #216
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Originally Posted by GregW / Oregon View Post
Only of related items, like wheel bearings, but that would be very rare.
Thanks
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      07-05-2014, 11:41 PM   #217
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Quote:
Originally Posted by Sedan_Clan View Post
Warranty of?
Manufacturers Warranty.
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      07-05-2014, 11:54 PM   #218
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Quote:
Originally Posted by 16M3
Quote:
Originally Posted by Sedan_Clan View Post
Warranty of?
Manufacturers Warranty.
You'll be fine. Spacers won't have any adverse effects 99% of the time. As Greg said, any issues will be rare.
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      07-05-2014, 11:54 PM   #219
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Originally Posted by 16M3 View Post
Manufacturers Warranty.
The Magnussen-Moss act prohibits denial of warranty unless direct cause-effect can be proven.
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      07-07-2014, 04:10 PM   #220
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Quote:
Originally Posted by tom @ eas View Post
Sure thing, here's the F80 dyno from last week vs E92 M3 (both DCT):


Surely you should (could) shift the e9x bhp and torque 1500 rpm off to the left to rebaseline and show the useable rev range like for like? I.e, 8200 rpm max vs 7000 rpm. Then you see something more interesting about the accelerative power difference at the "low" end and "high" end of the rev range of each engine.
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