Horsepower

[staholdn]

What is the wheel horsepower for a stock automatic and a stock manual? Is there a way to figure out your crank HP VS. WHP? What is the percentage lost through the drivetrain for both auto and manual. I'd like to get an estimate of my HP and torque without a dyno.

[JustinP10]

Originally posted by staholdn
What is the wheel horsepower for a stock automatic and a stock manual? Is there a way to figure out your crank HP VS. WHP? What is the percentage lost through the drivetrain for both auto and manual. I'd like to get an estimate of my HP and torque without a dyno.

I don't think there is really any easy way to tell, or calculate whp without going to a dyno. I may be wrong here, but depending on how your car is tuned up, the numbers could be quite a bit different. I'd have to guess maybe around 130-140whp... but it really depends. Stock 5-spds put down, on average, around 115-125whp. I think?

[G-Forces]

Yeah on older motors especially you can see some huge variation in dyno numbers. We had a guy with a stock NX2k run 112whp. It all depends on the state of tune or the engine. The only way you'd be able to get an estimate with out the dyno is to take it to the 1/4 mile drags. You car use the car weight and trap speed to give you a pretty good guess.

[AWD Primera]

GFORCES What is the wheel horse power of your car? I remember reading in a post a while back that you had 145hp or about 107kW at the wheels.
Heres why Im asking. In New Zealand we have Subaru Legacys and Nissan Skylines, both are good for about 225hp crank in stock form. However, when they are put on a dyno in NZ they put out about 116kW(This info is courtesy of a Performance car mag in NZ the runs free dyno days for punters wanting to see the power output of their cars.) Thats only 9kW more than your car but there is no way your car is putting out 200+ hp? Could there be a difference between NZ and US dynos or are all the cars that ive read about in NZ just shagged and not putting out their rated HP?
What is the approximate loss between WHP and BHP?

Cheers:sun:

[P10DET]

Originally posted by AWD Primera
[b]Could there be a difference between NZ and US dynos or are all the cars that ive read about in NZ just shagged and not putting out their rated HP?
What is the approximate loss between WHP and BHP?

I think it's because y'all are upside down there in the Southern Hemisphere. The cars just don't run as well that way. :jump:

Actually, it's possible there is a difference in dynos.

More likely the difference is due to FWD vs AWD. AWD just absorbs significantly more hp (kW).

As for the drivetrain loss (whp vs bhp), that can vary from car to car. As a rule of thumb (but all thumbs are different aren't they?) figure 15% for a FWD car, 25% for a RWD car, and God only knows for a AWD car.

I tell you what, just ship your car over here and we'll get you some good numbers. :jump:

[pche059]

wow...that means that I could possible out accerelate a stock skyline or a legacy....that's if i put some more work in my car! since our Primeras are sooooooo much lighter than those cars

hm...that was a nice piece of information to know

[Primal SMX]

Originally posted by pche059
wow...that means that I could possible out accerelate a stock skyline or a legacy....that's if i put some more work in my car! since our Primeras are sooooooo much lighter than those cars

hm...that was a nice piece of information to know

Yea! i'm with you! I'm gonna start now and advance the timing to run on 98 octane BP ultimate! yah! well while it is still rated at 98anyway as we all know our petrol can fluctuate!(is dat spelleded de wright wa?)

But seriously, aren't WRX's only rated at 85 kw at the wheels though? Cause i got blits by a stock one the other day going on to the motorway . I thought though that it was the torque figures that were just as important as the WRX has the higher rated torque rating (lots of ratings i know). Am i missing something?? I thought that you should not only take the hp rating of a car, but also the torque rating into account.

Oh and p10det that was funny, but seriously our cars are lighter than yours cause as gravity go's being upside down takes all the wieght out.

[AWD Primera]

Originally posted by P10DET


More likely the difference is due to FWD vs AWD. AWD just absorbs significantly more hp (kW).

I have seen a stock legacy RS with the AWD disconnected just running the front wheels and it only got to 95 kW! There engine stock is meant to put out something like 160kw at the crank.

I think it's because y'all are upside down there in the Southern Hemisphere. The cars just don't run as well that way.

The only reason we drive upside down over here is because our cars are so fast and produce so much downforce that its possible!!:hehe:

[T4 Primera]

Originally posted by Primal SMX
But seriously, aren't WRX's only rated at 85 kw at the wheels though? Cause i got blits by a stock one the other day going on to the motorway . I thought though that it was the torque figures that were just as important as the WRX has the higher rated torque rating (lots of ratings i know). Am i missing something?? I thought that you should not only take the hp rating of a car, but also the torque rating into account.

I think you have might have lumped the WRXs in with the other non-turbo Imprezas. The WRX Impreza has something like 205kW, so even with 40% loss through the drivetrain they'd still have 123kW at the wheels. I wouldn't even attempt to keep up with one. I'd thought about maybe replacing the T4 with one but they really are thief-bait.

[Primal SMX]

Originally posted by T4 Primera
I think you have might have lumped the WRXs in with the other non-turbo Imprezas. The WRX Impreza has something like 205kW, so even with 40% loss through the drivetrain they'd still have 123kW at the wheels. I wouldn't even attempt to keep up with one. I'd thought about maybe replacing the T4 with one but they really are thief-bait.

I thought only the Sti version and the newer Legacy's were 205 and the old bog standard WRX was 160 at the flywheel. Then 45% of 160 is 88? I read this in those Australian Mags, like Hot 4s and Fast fours etc. This is their claims. And youre wright on with them being theif bait and i also was going to get one, but there was just far too many around and now theres even more!

"The only reason we drive upside down over here is because our cars are so fast and produce so much downforce that its possible!!"

Yes i would have to agree with you there! Haaahaaahaahahaa!!!

[T4 Primera]

Originally posted by Primal SMX


I thought only the Sti version and the newer Legacy's were 205 and the old bog standard WRX was 160 at the flywheel. Then 45% of 160 is 88? I read this in those Australian Mags, like Hot 4s and Fast fours etc. This is their claims. And youre wright on with them being theif bait and i also was going to get one, but there was just far too many around and now theres even more!

You're probably right, I only got the 205kW from talking with a co-worker and I'm not too schooled up on the scoobies. The 40% was just an arbitrary number I picked.

I carpool with the above co-worker who drives an auto '91 Legacy GT Wagon with 161kW - common as muck - and that thing is F.A.S.T. fast. If his car had four adults in and a full tank, and mine was empty with just a driver, I might just be able to keep up. I tailed him once in my turbo mitsi, he rapidly went away from me but the VR4 in front rapidly went away from both of us. The Impreza is somewhat smaller so should be quicker.

BTW, his car has been broken into once and stolen once. When it was recovered, it was found out Raglan on one of the roads they use in the WRC. It had been slid into a bank and they made off with the CD and left the motor running. Also, all this extra power costs big in transmission work around 100-120k km (at least in the early models). He had his overhauled at a cost of $4k

[jasestu]

Originally posted by Primal SMX


Yea! i'm with you! I'm gonna start now and advance the timing to run on 98 octane BP ultimate! yah! well while it is still rated at 98anyway as we all know our petrol can fluctuate!(is dat spelleded de wright wa?)

Fluctuate it does, but it's the 91 that tends to vary the most, the higher octane fuels seem to be more consistant... Damnit I can't find anywhere in Palmy with the 98... What's the pricing like relative to 91 or 96?

[jasestu]

Originally posted by T4 Primera
BTW, his car has been broken into once and stolen once. When it was recovered, it was found out Raglan on one of the roads they use in the WRC. It had been slid into a bank and the made off with the CD and left the motor running. Also, all this extra power costs big in transmission work around 100-120k km (at least in the early models). He had his overhauled at a cost of $4k

Yeah, insurance on scoobies is insane, and they are certainly a popular choice for thieves, not that I know anyone that does that kind of thing...
I briefly considered getting one, but only briefly when I realised they were overpriced and often nicked...

[Primal SMX]

Originally posted by jasestu


Fluctuate it does, but it's the 91 that tends to vary the most, the higher octane fuels seem to be more consistant... Damnit I can't find anywhere in Palmy with the 98... What's the pricing like relative to 91 or 96?

98 is always 2 cents dearer a litre than 96, and thanks for that information as i didn't realise that. I've been using 98 synergy feul from Mobil but after a few months it didn't seem to go any better than 96 so i have changed to 98 Ultimate from BP and the car seems stronger! Go figure.

[jasestu]

Originally posted by Primal SMX


98 is always 2 cents dearer a litre than 96, and thanks for that information as i didn't realise that. I've been using 98 synergy feul from Mobil but after a few months it didn't seem to go any better than 96 so i have changed to 98 Ultimate from BP and the car seems stronger! Go figure.

Which is a little odd because all the fuel at those two stations should be identical as it's all offloaded from the same tankers in port. Many years ago there used to be some differences between companies when they used to add their own additives to the fuel, but that stopped. However I'm not too sure what Mobil's up to with the Synergy range, whether it's just a re-branding or whether they're actually tweaking the additives again. Oh, the other thing that could lead to differences is stale fuel (evaporation of volitiles, sedimentation of waxy components). I don't suppose the 98 turns over very fast, so there's potential for it to get stale sitting in the tanks.