Starting at 260 published HP for my 03 6MT sedan, how much HP do you think I have?

260

+ Nissan sand bag, 20?
+ Stillen Cat Back, 7?
+ Z tube, 2?
+ K&N in stock box, 1?


Thinking saying I have 290 is overstating?

 

I can't tell if you're joking or not.

Upgrades like intake and exhaust aren't additive. For instance an intake that has advertised gains of 8HP and an exhaust that has advertised gains of 20HP doesn't add up to 28HP in gains.

Advertised gains of 8HP typicall equal 1HP in the real world. 20HP? Maybe 15.

If I added a catback system and an intake both, I'd expect around a 10HP increase but that's only because I'm a cynical bastage.

...Add to that the fact that in life I'm cheated every time, which means I can assume a stock HP of around 240 and I'd be close to stock numbers with the intake and exhaust.

Then I could add plenum and hit 259

 

i'm serious...

when someone says, "Hey Mize, how much HP you got?"

I wanna tell them a realistic number based on the above stuff...


p.s. why aren't they additive???

 

Generally a stock 03 6MT has about 230-233 at the wheels. The only way to know for sure is to get your car dynoed.

 

I don't think saying 2 hp for a ztube is being outrageous. 2hp could be a definite additive claim, don't just spew out things you read in other forums. An intake + exhaust combo is going to make more power than just an exhaust (or just an intake). Thus, mods are ADDITIVE gains, they're just not directly additive in the manufacturer's claims or in their sole gains. For instance, if an exhaust makes 15 whp and an intake makes 15whp, than combined they may make 23 WHP not 30.

Based on his numbers, the only one I'm iffy on is the sandbag claim and the K&N drop-in.

The Stillen exhaust has proven it's worthiness and probably for closer to 12-15 WHP. The Z-tube probably does make about 2, the K&N is more of a longevity mod than a performance mod, I say it gives 0 or a fraction +/-.

Based on a 20% drivetrain loss (pretty common for a RWD car, 17% might be a closer figure, but close enough), 260 crank HP equates to 216 WHP. Automatic tranny cars aside, 6MT's appear to stock down anywhere from 215-225 depending on conditions, weather, dynos, etc. Thus, let's say 220 is the cummulative average. That equates to about 265 HP, so your sandbag addition should only be 5 HP. Additionally, this only is true for 6MT's and is likely from the slightly modified ECU's and electric fan setup that the auto's don't have. I don't pay any attention to automatic dynos so I don't have any base figures to go by, but if you have a 6MT, which it says you do, then 5 HP.

I'd say based on your mods, your crank HP =

260
+5 sandbag
+12 stillen
+2 z-tube

277 HP, not too far off from the 2005 figures. Torque is a different story and how much your gains are throughout the power band are not factored into this EXTREMELY rough estimation.

In addition, you really should strap yourself to a dyno, get an accurate WHP number and multiply it by 1.17-1.20; that's about as accurate as you will get.

 

This may be true, perhaps my numbers were a bit low, it's been a while since I've looked at a stock dyno. If anyone else can confirm or deny this that'd be beneficial for the sandbag.

That said, if 230 WHP is the true stock value then 276 HP is the truer figure which would result in a +16 HP sandbag value; sounds kind of high to me. If I recall, 230 seems to be the higher dyno's I've seen on this board, 225 seems to be the high-average, and 215 the lower end of the spectrum. Again, it's been a while since I've seen a stock dyno.

 

I have a suggestion, why not just buy a faster car?

 

thanks guys, i think i'll call it 285

don't really care what it actually is, just want to be able to back it up if someone says, "no way 285, i read 260, you're FOS"


p.s. BrianV, your car looks hot, putting on my 350Z springs tomorrow, can't wait, i'll be sure to post some pics,

 

OK So you said it better than me but that's exactly what I meant.

 

Gracias!!!!!

doogy, I figured that's what you meant, but some people interpret things incorrectly.

 

Get your car dynoed then you'll know for sure. My $0.02.

 

i don't wanna get my car dynoed, my mods are very popular, just want an estimate, i'm calling it 285 crank.

 

You'll be lying. It almost sounds like you're talking about bragging rights; to get those you'll need some proof. Guessing and Internet chat room speculation will not earn you bragging rights.

So you're thinking, "Well, I know it has to be more powerful than stock because I did all these mods." Do you know this to be a fact? Is your car in fact 260hp the way the manufacturer claims? There's variation in any manufacturing process. Some engines just turn out to be more powerful than others. For example, in the semiconductor industry, you may know that some (otherwise identical) CPUs offer more over clocking potential than others. That's just the nature of manufacturing.

You may have started with a 250hp stock motor. Or a 270hp stock motor. Add your mods to those motors and you're going to be making exaggerated claims or selling yourself short.

I think you're more curious than boostful. If that's the case why not say, "The manufacturer claims the stock motor to be 260hp and I've added some mods. I'm either close to breaking 300 or about where I started, your guess is as good as mine."

Or you could just stick with 285.

 

Dude calm down, he's just looking for a rough estimation in his head, I'm sure he'll disclaim that his calculation is purely speculative. There's a degree of error in every estimation. He doesn't need to pony up $60+ for a dyno if he feels confident with an estimation. There's really no point to dyno a car unless you're looking to tune A/F, timing, or other variables. The only reason would be for pure bragging rights which in turn really do nothing for you, it doesn't make your car any faster, it doesn't do anything for you, and you'll never know how much each mod contributed to the net gain.

I think what he asked is a fair question, and I think the numbers that are being spit out are within a reasonable range. Even if he gets a real dyno, he'll be measuring WHP and will be using a calculation that has an unknown degree of error to create a crank HP number. It's a flawed system to start with, what's the point in paying money to conclude a flawed system. It's clear he wants a number he can justify as crank HP so either way he's screwed. Don't act like you're some ultimate 'god' on the subject and that his value is completely worthless, it has SOME value and SOME merit, but it's certainly far from conclusive. The last sentence in your statement is the most constructive statement here. He won't be lying by stating he's making 275-285 HP as long as he and whoever he tells is aware of the calculations and estimations involved.