Very interesting. You did not explain this in detail but your comments lead me to believe you understand the implications of dyno results. I have spoken to some very successful mechanics and an engineer, they simply do not get it. A dyno run shows real time torque for an engine but not HP. HP is work over time, a ten second dyno run showing 300 hp is only extrapolating the engines hp potential by using torque figures. The dyno can say if this engine was run at this torque for an extended time it is capable of producing a given HP, not that it produced that hp in ten seconds. If you really want to piss someone off calculate how much hp a car actually produced in a 12 second run.
Making safe power: What it takes and why it breaks
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Can't go into too much detail or most people will be lost on this forum.
Yes, dyno measures tq, hp is calculated from the tq and rpm.
TQ × RPM ÷ 5252 = HP
HP make sales, TQ wins races
I love doing a calculation to show the revolutions the crank actually turns during a 1/4 mile pass.
Cold air
Colder air is more dense and makes more power per psi boost. Here is an example of a 250 whp VT at a set psi boost being fed different intake air temperatures. Notice power goes from 250 whp to 261 whp due to a 12°C colder intake air as the only change.
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Colder air is more dense and makes more power per psi boost. Here is an example of a 250 whp VT at a set psi boost being fed different intake air temperatures. Notice power goes from 250 whp to 261 whp due to a 12°C colder intake air as the only change.
Higher flow parts
Having parts that help the engine flow air more efficiently, be it on the intake side, charge air side, or exhaust side, will improve the volumetric efficiency of the engine which improves power at any given boost level. Here is an example of a 250 whp VT with the only change going to increasing the volumetric efficiency by 10% which in turn increases power by 10% now up to 275 whp.
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Having parts that help the engine flow air more efficiently, be it on the intake side, charge air side, or exhaust side, will improve the volumetric efficiency of the engine which improves power at any given boost level. Here is an example of a 250 whp VT with the only change going to increasing the volumetric efficiency by 10% which in turn increases power by 10% now up to 275 whp.
Elevation/barometric pressure
The barometric pressure which can change with elevation and weather conditions will also change power output. Here is an example of a 250 whp VT at sea level vs the same car at the same boost in Denver CO only making 230 whp.
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The barometric pressure which can change with elevation and weather conditions will also change power output. Here is an example of a 250 whp VT at sea level vs the same car at the same boost in Denver CO only making 230 whp.
Actually it takes torque and hp to win races. Plenty of very high torque engines out there that can not win races. Most HD and large air cooled v twins, tractor engines, off road heavy equipment engines all make massive torque. Large torque figures are great and provide impressive initial acceleration response but a high torque engine that can not rev and turn that torque into work over time, hp, falls on its face. A modern 600cc sport bike has little torque when compared to a 1600 cc v twin yet will absolutely bury the twin at the drag strip. The 600 may have less torque but at 14k rpm it can apply its somewhat lesser torque 3 times more in any given time interval than the higher torque but slower turning v twin. Torque=right now, hp=work over time. Look at it this way, you put a two foot breaker bar on a wheel stud thus exerting great torque. You can easily move the car this way due to the torque applied. But how long even at this high level of torque would it take you to move the car 50 miles? Now introduce hp, how many times can I exert that torque in say one hour? The answer for a human is very few, far less than 1 hp. Yet a high hp engine can move that load 50 miles in less than an hour.
All about the power curve and having the torque where you need it to win races. HP is calculated and not measured like torque as you know. Peak hp or peak tq is only good for bragging rights and making sales. This is what the saying means.
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and you need to name it by tonight.
I guess I need to make an informational post on N2O next is what you're telling me.....And the best way to make that air cold.... NITROUS OXIDE BOOSTERS
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Name the movie and win... nothing.
Doing my best to inform and not lose people as is.....
Sure. I'll read it. I've seen some reports of good gains with nitrous on gf4j's. I think the gains were higher than the shot. I assume that would be due to the cooler charge. AND, I think that was a dry shot.
And the movie was Black Sheep with Chris Farley and David Spade..
The power gains can be higher or lower than the jet suggests but many factors go into that. Bottle pressure, jet location, IAT, and state of tune are the biggest determining factors.
I've seen a car make 299 whp with an 80 shot after being tuned to 220-225 whp area. Want to say mods were intake, catless dp, tune, and the N2O kit. The transmission did not want any more than that due to slip and I cringed watching the dyno pulls. State of tune was not great.
A dry shot is never a good idea on these cars nor is a sudden or large quantity. The shock to the parts and/or sudden fueling changes will break things quicker than anything else. This is why I make custom fuel line for the VT peeps to run a wet kit if they want to run N2O.
I'll add more later when I have more time and gather my thoughts on what to add next.
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56 Posts
I have a question. Recently saw a build on YT of a VT1 with a N2O cooled intercooler, reporting a 50whp difference (impressive!). You've talked about the benefits of IAT's on this application. I'm wondering if that is an efficient use of the N2O or would it be better spent as a wet shot?
Carbon dioxide would be a cheaper alternative and have zero volatility for a safety factor and easier to obtain.
All you're doing is spraying the liquid of either the nitrous or CO2 onto the fmic to cool off the air for a denser charge.
Efficiency would go the way of the water/ meth injection as @trdtoy has mentioned as the ingredients are cheap and it works by his published data logs of iat's.
Good question and I'd like to hear more on this question too. 👍
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guess he is going to have to make that post on N2O lol.
I'm all for WMI. I just don't know which is more temperature efficient, Methanol or N2O (or CO2). Would a 50shot to cool the intercooler better at adding that power through cooling, or at 50 wet shot? How does that compare to running Methanol? Both? Diminishing returns with charge temperature? The possibilities! (totally not me plotting ways to blow my DCT for fewest $$$'s)
Intercooler sprayers of any type cool the intercooler core down which lowers the IAT by the efficiency of the core itself. If using N2O for example it would gain more power injecting that into the engine as you do not lose the inefficiency of the intercooler(with proper nozzle placement) and will thus cool the air charge more. Also the N2O will make more power with a more efficient cleaner burn of the fuel. So simple answer is wet shot will make more.
N2O is the most efficient cooling when injecting into the engine than methanol injection. Also N2O is way more costly to use than methanol injection. Can run both no issues as long as setup and tuned correctly.
Not many VT out there can take advantage of N2O to the point of making it worth the investment. The one I'm building I'm toying with the idea of having N2O wet shot on it with a big single G35-900 or G35-1050 turbo to get to 1k hp. Not quite sure the path yet I already have the N2O kit designed and mostly made.
Not sure if this is something that you want to write up anything on or not but I find intercooler sprayers (misters) interesting. There's 2 types, the "soak it down with a good spray" type and the "mister" type. From what I've read the misting type is harder and costlier to build but the fine mist works better for evaporative cooling. The question at that point is, whats the cost difference between a good sprayer setup and a good wmi setup? And, does that difference justify the running one setup over the other?
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