ScionFred

iTrader: (1)

Sorry if this is old news but I haven't seen it posted here.

http://www.importtuner.com/powerpage...rs5/index.html

FromTheOld

Good stuff to know. Automatics rob power like crazy

ScionFred

iTrader: (1)

They do? I guess with modern AT's offering nearly identical performance and fuel economy, I never noticed it.

AAG

iTrader: (1)

Wow 16 hp and 18 lb/tq from bolt ons?! I wonder how much better it would have done with a full cat-back exhaust system.

FromTheOld

Automatic transmissions always rob power like crazy in every car, but dynos aren't always the full story in performance

Automatic xB2 Stock - ~125-130 WHP
Manual xB2 Stock - ~150 WHP

ScionFred

iTrader: (1)

Unless those WHP figures were obtained on the same dyno under the same atmospheric conditions, they're apples and oranges. AT's rob some power but that looks excessive.

FromTheOld

This is true, which is why I put "~" in front of those figures, but generally, automatics rob a lot more power than manual transmissions do.

draxcaliber

traditional slushbox automatic transmissions (which the xb has) do rob alot of power form the engine, because it is much less efficient way to transmit power than a manual transmission. this is why acceleration times between the same cars with different transmissions are often much slower, that and slight gearing differences.

however, automated manual transmissions that actually operate a clutch, like vw/audi with their dsg gear boxes, and porsche's pdk, do make the same power, and actually shifter faster than traditional manual transmissions, so they transmit the same power that the manual does.

coryjames

i will stick with my stick oh yeah i enjoy driving so yeah autos have there place for getting grocery's and teaching girls to drive

FromTheOld

lol, you sound so close minded and ignorant when you stay stuff like this. They also have their place for being faster than manual cars in drag racing too (well, when automatics are paired up with turbos), which is what most people care about these days. Yeah, stick is faster on the track, but that's only if you're actually a good driver and not some wannabe racer.

VonStarINC

+1

coryjames

yes a auto is more consistent and better for drag racing but the fun factor is gone dog boxes and no lift shifting are also in play now with 2 step boxes and stuff like that either way you look at it the best way to harness power is a mechanical linkage not through a slush box the holding caps of a auto are also less they are more finiky and take some time to set up manuals are simple not relying on fluid pressure not to mention the heat factor

FromTheOld

Yes, two steps can make manuals build boost off the line but you're still losing boost between shifts unless you powershift, which is dumb. Not to mention not everyone buys two steps. Also, a well built automatic transmission with a transmission cooler can easily take tons of abuse. The fact is, if you modify an automatic transmission to shift fast, it's actually making it more durable. The saying goes, "what you feel, your transmission doesn't". It's true, believe it or not.

Also here's another question, are you willing to put up with a clutch that's uncomfortable to drive just so you can handle the power in a manual car? Yes, there are twin disc clutches, etc. but the fact of the matter is that if you're not spending over 1000 grand on a damn clutch, you're going to be uncomfortable driving.

I'm not bashing manuals, and I'm not saying automatics are the best, but they both have their purposes and neither transmission choice should be dismissed so easily.

ScionFred

iTrader: (1)

Duly noted and agreed in principal. I still think that 20-25whp seems a bit much in this case. IIRC I saw a 140whp dyno result for a 5-speed somewhere but I can't seem to find it now. I'm thinking more like 10-20whp loss for the AT but I could be wrong. I did find some stock XB 1/4 mile times of 16.1 sec (MT) and 16.5 sec (AT). That's a significant difference but I don't recall how to convert that to an estimated whp difference.

ScionFred

iTrader: (1)

Agreed but you neglected to mention Ferrari and Buggati.

AAG

iTrader: (1)

FromTheOld your statement about needing to spend a grand for comfortable clutch is false. Most clutches are about half that and are just fine. Heck I prefer a stiffer clutch when driving, it doesn't feel like it's going to break (like the stock one haha).

And you are right each have their own place, but the auto in the xb is plain weak. It would never be able to handle 300+ whp like the stock manual transmission unless you spend a lot of money on it. It'd be a different story had the auto xb came with a dsg transmission.

FromTheOld

Most twin disc clutches are over 1000, and I know what it's like to drive on a stiffer clutch. It's not really that bad, but some people prefer the ease of driving the stock clutch (which is why twin disc clutches are great. They can handle power while having the stock feel).

Yes, I know the automatic is plain weak. It has to be built up, which DOES cost a lot, but adding a transmission cooler to it allows it to handle SOME power before needing a build. After all, the #1 killer of automatic transmissions is heat.

Like I said, it's all preference. I notice that the younger crowd hates on automatic like crazy, and it's really unjustified.

coryjames

you know my car probably makes the same whp as a auto just cause im at altitude less air density the rule of thumb it we loose about a second in the quarter mile here from sea level i run a stage 5 clutch master witch will hold 500ft pounds no problem the since we have a hydro clutch its not all that much heavier then stock

VonStarINC

No he didn't ;D

AAG

iTrader: (1)

[quote="FromTheOld"]Never said I hated it, I just don't like it when it's with a 4 cylinder engine. I do prefer an automatic in a v8 rwd vehicle though.