By next week I will have the Fireballed Head and Cam combo and I was thinking about a LSD. I know all the benifits of the LSD but I have always wondered if it adds to the tranny loss? If so how much WHP is lost?

 

There are always frictional losses as well as rotational mass loss.
Don't know what it would be for a MINI but I'd suspect it's less than 10WHP.

 

The gains will out-weigh any drag/weight from the unit. What good is power if you can't put it to the ground?
I doubt there is much loss with a LSD. You are transfering power where its needed. I wouldnt think it would even be measurable.

 

doood, you are decking this car OUT huh? You planning on using any of it?

As in, October 22nd Autocross, you gonna be there? Let's see what your baby can do.

 

mario...
i have the stock lsd and ran 176 at the wheels w/ my "HAI", alta exhaust, 15% pulley.

others ran similar numbers w/ out lsd.
some ran greater numbers w/ software...
based on the Gintani dyno day w/ scmm a while back
http://www.clubscmm.com/board/index.php?topic=3206.30

which lsd are you looking into?
-glen

 

just went to a car with lsd and its absolutely amazing. GET IT, no matter what frictional losses you get because of it!

 

if you're using lsd i doubt you'll notice the change if any in whp.

 

it's catch 22 it's the guy with the 200 hp yugo with the 5 lb wheels .(hes got it but he can't use it ) probably shouldn't include yugos in annalogies huh?

 

No measured change in fuel consumption before and after installing a Quaife. I'm not saying there is no parasitic impact, but that it wasn't large enough for me to measure.

Increased parasitics in the driveline will show up as both increased fuel consumption and reduced whp. Without having personally tried it, I really doubt that you could tell the difference on a chassis dyno. Probably no where near 10whp.

Even if it did contribute to increased power/fuel consumption, the added traction is more than worth it if you do anything more than benchrace or trade dyno sheets.

Scott
90SM

 

Shucks. I was hoping you'd know the loss.

Just for info did you also go to lighter components at the same time? Lighter FW and clutch for instance? Better tranny fluid?


Also keep in mind that the LSD does nothing 99% of the time during street driving so you really won't see a mileage difference.
The only time you get a real impact is during those brief periods of engagement.
It you're doing a lot of that on the street well then shame on you


Depending on the LSD design there is also some friction during deceleration. Clutch type diffs are more prone to this. No biggie just something to keep in mind.

 

To some degree, you're answering the question right there. IE not doing much most of the time. This would be especially true in a straight line once you get out of 1st gear.

To comment on other questions, the only other change was a pulley install. While that would initially seem to really impact fuel economy and power (it does both to a degree), Helix installed their version with a fixed hub and interchangeable outer portion. I started have stock, 15% and 19% versions. The fuel consumption comments were from the stock pulley diameter and no other changes at the time.

The Quafe diff is a helical style, not clutch or viscous. As for diff engagement on the street, you're correct that you only feel the difference on the street if driving very aggressively in the dry, but I also drive the car all winter in the snow. The diff is very noticable in the snow, though the torque loads are far lighter than they would be in the dry.

I've recorded data (date, gallons, $/gallon, miles, trip miles, tire type and size, plus mpg and avg mph from the trip computer and any notes such as higher than normal amount of city driving or an autocross) for every single fuel fill for my MINI, so I've got over 4 years and 92K miles worth. I spend the vast majority of those miles running the same routes back and forth to work (normal day = 85 miles round trip). I go through a couple tanks a week, and have a pretty good idea if it was "typical" or if I was playing. The average mph helps in that too.

Not highly scientific, but I'll bet you a 12oz soda of your choice (my getting really serious standard bet ) that the loss due to an LSD would be low enough that you'd never see it without a thorough DOE and MSA.

Anyway, I think we are actually agreeing despite chasing around in circles. The loss is there in theory, but it's tiny.

I will note that I CAN tell the difference if I drive a couple days on the A048s vs M500s. I also could between Azenis and Arctic Alpins. More recently, the DT BPV also seems to mildly impact fuel consumption (~1mpg or so) and intake manifold temps (4 to 10 degsF steady state cruising depending on vehicle speed). Turning the AC on is worse (windows up either way).

Scott
90SM

 

Just for grins what kind of mieage do you get?

Most of mine is urban unfortunately but like you I record every tank unless I do a partial fill for an auto-x weekend.
I've gone from a best of ~25.5 US MPG to my current ~24.5 US MPG with around 30 more HP than I did stock.
Definitely want to get an LSD.

My question about what else was installed was really just curiosity. I do plan to go with a lighter FW/clutch combo in the future and was wondering how that felt along with the LSD upgrade.

My original less than 10 WHP statement was based on that being a bit less than the whp loss of a limited slip rear in a Chevy 12 bolt. Even when not engaged the spider gears and clutch pack do generate some loss. Of course this unit is just a bit bigger than the MINI LSD. So I knew less than 10 WHP was a safe bet but definitely not the axtual figure.

 

I average high 20's (27-28mpg) most of the time. If I'm really gentle and keep the highway speed no higher than 60mph, very low 30's. Autocross tanks (~200 miles normal driving plus a 1 day event) end up in the low 20's. When the car was stock (or at least mostly so) I could get low 30's and as high as 35mpg if I really worked at it and stayed on rural highways with a 55mph speed limit and kept of the interstate on the way to work.

All of the above would be hand calculated mileage. I normally just watch the trip computer's value, which is more optimistic. Typical tanks would say 34 plus a couple tenths, or 35.1mpg if I stayed off the highway and didn't play at all. Really working at it might get a 35.6mpg for a tank. I'll occasionally see trip computer values as high as 39mpg if I pull out of my favorite gas station and cruise gently down Indiana 31 at 55-60mph. Getting into traffic lights causes that number to come down several mpg pretty quickly. No way I'd get a whole tank like that, unless I hopped on the I-65 and headed for Atlanta. It might even get better, since the semis would be shoving me down the interstate with their bumpers before long.

The MINI trip computer has always read several mpg high. Adding the JCW injectors and changing to shorter tires just screws it up even more. Still, it is a quick and easy way to see if my mileage is changing due to a failing O2 sensor or something like that.

Scott
90SM