rico

hello all,

i really feel like the bhp numbers i see people quote on this forum are very optimistic. from reading on other forums out there, i've heard many qualified and experienced people suggest that the standard turbo for an evo is at the most good for ~400bhp with pump gas. just recently i heard someone mention this much power at the wheels!

unfortunately i'm not able to keep up with this site too much, but the few times i do get a chance to come over, i have just gotten the sense that the numbers seem quite high. for instance i seem to remember a lot of people quoting 300whp, which from my understanding equates to 400bhp. well that to me, is a really excellent achievement as you would then literally be getting the absolute most out of your turbo. however, the mods to these cars seem rather minimal, so i of course end up a bit skeptical.

so i am curious what your thoughts are on this? maybe you could give me a bit of review on the progress your evo 8's have made with the standard turbo?

also, i have what appears to be a fairly accurate algorithm for calculating bhp from 1/4 mile results. perhaps you guys could let me know what kind of 1/4 mile results you have achieved with the standard turbo as well? however, i do need a fairly accurate weight measurement. how much does the usa evo 8 weigh? and does this figure include fluids in the car?

thanks for your guys time. i don't mean to be insulting or causing trouble. it's just that i own an evo with a standard turbo and a few mods and am a bit suprised by the ease of which people claim to have achieved 400bhp.

so i hope to understand more about how things in the states are going with evo 8 tuning, and wish you all the best.

brandon

MalibuJack

iTrader: (5)

Actually, calculations are only accurate in a perfect world.. The 1/4 calculation is pretty well known, however it doesn't take into effect wind resistence, air density, gearing, etc.. But I'll bite..

The problem with HP calculations based on quarter mile, is they assume optimum gearing, which will influence the values, a high horsepower car with desert gearing would reflect a fairly slow (but probably impressive) quarter mile time, but the trap speeds would be significantly higher since its still accelerating

When my car was bone stock, I ran a 12.93, I would say weight should be around 3600#

(FWIW this is how the GTech pro calculates most of its information in the same way..)

Now, keep in mind, HP ratings for turbos are not necessarily the maximum power output of the engine/turbo combination, its just at what point the air volume (maximum boost) ends up having diminishing returns... By reducing restrictions, and by optimizing the efficiency of the air pump (engine) you can actually gain quite a bit more power than just forcing more air into it.

MYEVOVIII

iTrader: (35)

I thought the Evo weighed around 3,260 pounds are you factoring in the weight of the people in the car at that time?

MalibuJack

iTrader: (5)

Let me point out that this in no way implies that what your saying isn't true.. Unfortunately Dyno numbers vary wildly, and are just as innacurate at determining true horsepower because they all rely on the same types of calculations and correction values.

The true value of a Dyno is for tuning, because the deltas (differences in horsepower) on the same car under similar conditions with modifications will reflect its gains as a value from before, and after (Delta), which at that point could be fairly accurate. (Assuming air density, Ambient temp, humidity, engine temp, and the car's health between runs is a constant)

MalibuJack

iTrader: (5)

Absolutely.. Unladen weight (Dry weight) is probably around 3260.. you have to add fluid weight, gas, and the humans in the car.. also, when your driving, the downforce on the car at speed adds what can be equivalant to adding weight.

3K

iTrader: (9)

MYEVOVlll is correct. The evo and the sti both weigh the same at 3260lbs. I saw it on Car and Driver. They weighed both vehicles at a weigh station, and both were exactly the same at 3260lbs.

Fourdoor

iTrader: (11)

Was that with a full tank of fuel or dry? Just wondering.

If you figure that as fully fueled then add 190 lbs for a driver (or what ever your weight is) and subtract about 50 lbs if you are running at 1/2 tank of fuel and you get a grand total of 3400 lbs. Aerodynamic downforce has no effect on your weight for these calculation....you are actually using the MASS of the car, not it's weight in the formulas. I used the online HP calculations and came up with almost exactly what I ended up getting the next day on the dynapack dyno. 235 WHP calculated based on my trap speed in the 1/4 and then dynoed at 232 WHP. Pretty damn accurate in my view!

To the original poster, if you are used to seeing dyno dynamics figures, then most of the stuff you see from North America will seem inflated. The dynojet dyno, and the Dynapack dyno both are quite a bit more close to the "real world" figures that you are putting down at the wheels. With a dyno dynamics 300 HP at the wheels may be over 400 HP at the crank, but on a dynapack 300 HP at the wheels is around 353 HP at the crank shaft.

Keith

MalibuJack

iTrader: (5)

Thats a good point, Downforce really only makes a difference at sustained high speeds when your trying to maintain that speed, similarly with a cars aerodynamics.

I keep forgetting we're not dealing with optimum gearing where you've reached some level of terminal velocity and these things could make a difference.

For what its worth, the calculation estimates 319hp (at the crank) for my Evo when stock for my 12.93 run with 3500# weight.. I gotta admit thats probably not too far off, its pretty well known our cars were underrated severely at 271 which many were probably 300 or slightly over.. I don't have a dyno sheet of the car stock to really have any level of confidence, but I'd have to say thats within 15 horsepower..

In the real world though, there are many factors that will influence your times, and therefore bias these horsepower calculations. I really wonder what our cars could do if they possessed optimum gearing, on the other hand, with optimum gearing for the quarter, you'd have terrible top end compared to stock..

To make a long story short, Weigh your car at a weigh station with the amount of fuel you plan on running at the track, and make sure you have your altitude (since you may have to apply a correction to your quarter numbers)

have fun, they will be close enough if you can make several consistent runs after each modification and average them, your differences should reflect the gains within reason.

Secret Chimp

iTrader: (2)

Curb weight is 3260 lbs for the Evo....not the dry weight. That includes a full tank of fuel and all other fluids. MalibuJack, you don't weigh 400 lbs, do you? :P

MalibuJack

iTrader: (5)

Last I checked I hadn't eaten THAT many krispy creme... I weigh about 180 so when I calculated at 3500# its pretty close to what the running weight would have been... Someone HAD to have weighed their car recently to get an accurate number..

Fourdoor

iTrader: (11)

If 3260 is the weight of the car with a full tank of fuel, and you weigh 180 lbs, then your race weight was 3440 or less depending on how much fuel you had loaded. Fuel is aprox 7 lbs/gal for gasoline so figure subtract aprox 25 lbs for each 1/4 tank of fuel less than full. Most people race with somewhere between 1/4 and 1/2 tank of gas so in reality you were probably right around 3400 lbs race weight instead of 3500 lbs.

Keith

MalibuJack

iTrader: (5)

Yeah I know.. Just didn't want to get too optimistic.. Geez, most people don't even want to believe a bone stock Evo ran a high 12 let alone producing in excess of 300hp..

TisayLuv

I think the 16G that is used on the US EVO VI maxes out around 360bhp. But then again, Ultimate Racing was able to crank out 400bhp with their set-up and ran high 11s with the stock turbocharger.

Fourdoor

iTrader: (11)

By reducing the weight component of that equation you will get a LOWER hp number.....thus you would be being "less optomistic" about your power output, not too optomistic

Keith

MalibuJack

iTrader: (5)

Oh yeah, brain fart..