Thanks guys-thats INSANE!!! Nitrouz, at what speed do you hook up with that much power? I still have trouble hooking in 3rd sometimes I couldnt imagine that.

 

 

That is very impressive power at those psi levels. Congrats Alex. Great work Sam.

 

Exactly, so how would these numbers/psi compare to a Sam/GTM tuned APS TT kit on a non stroked GTM motor and also a Sam/GTM tuned APS TT Extreme on a non stoked GTM motor? How much power does the stroked motor really contribute? If that make sense. Using the same contributing mods, Alex has of course.

 

12 psi 3.5L vs 12 psi 4.24L

makes about 100 whp/tq difference across the entire powerband for the 4.24 stroker, extreme headwork and cams

of course this dyno has the regular and extreme APS turbo kits so the extreme kit has bigger turbos which will have less low end power and more upper power

 

Its still not determined if the stroker is making more power/ that a non stoked motor with the same mods. Your not going to gain, anymore power just becuase you strap on a stroker. Yes torque would be increased, but that doesnt necessarily mean hp will also.

The graph shows a fully built head+aps extreme turbo kit vs a stock motor regular aps extreme kit. Granted there is a 100 hp difference, but if you were to port and polish the heads, cams and valve train work in addition to the larger extreme kit, I think it could easily make the same hp/ pound of boost as the stroker.

 

Sentry, what program do you use for the overlays?

 

bigger engines are not as efficient at high revs, but headwork helps even out that flaw.

6500-7000 rpms really isn't that high of a rev anyway


I dunno though, bigger engines make more power. It's a classic power gainer mod
no replacment for displacement, yada yada yada


just photoshop

 

Not really. This is the same reason why, the S2000 made more torque, but didnt make more power, becuase it went up in displacement.

 

yeah but the S2k revs to 8200-9000 rpms depending on the year. That might be enough revs to taper off a gain up high from displacement

 

Increasing displacement decreases torque because a greater volume of air (and thus fuel) is combusted per revolution, imparting more force on the crank and thus producing more torque. However, without changing the rest of the setup, you are not actually flowing more total air, so power stays the same. That is why a stroked engine generally pulls the curve to the left and inflates the torque curve (more torque produced accross the RPM band), but doesnt increase HP on a given setup (the ONLY way that would happen would be if the HP curve is still rising at redline, meaning more airflow could be obtained at the same redline by increasing displacement

 

well it remains to be seen then what'll happen on the VQ with it then. I agree with that the lower rpms see the most benefit with a stroker kit.

IMO I still think at 6500-7000 rpms the upper rpms might still benefit a little, especially if FI is involved. Headwork increases power across the board, but sees the highest benefit in the upper rpms compared to the lower rpms.


I've seen before/after dynos with stroker kits by themselves that don't rev to 9k rpms - like jeeps where they rev to 5500 rpms as well as other dynos of cars with FI like talons, EVO's, and mustangs, and they gained power across the entire band except it wasn't as great of a gain in the upper rpms

 

congrats on the numbers!

one question - why does the spool and power delivery suffer with the added boost? I haven't seen this on any of my cars and was just wondering why there's such a big difference in spool and power below 4.5k with just 4 more psi of boost...?

 

Lets take a look at the domestic side for a second:

L98(corvette)
LT1(camaro)
LS1(camaro)

The three listed, all have similar displacement which is 5.7 liters and all weigh nearly the same. If we floored all three simultaneously, each would throw you back in your seat, with identical force, becuase they each make about the same ft/lb of torque. But as speeds increase, you would see that the ls1 starts to pull ahead and finishes the 1/4 mile .5-.8 seconds faster, while trapping over 8mph faster. This has more to do with, being able to stay in gear longer, not necessarily a product of displacement. The same could be said about a GSR vs LS. Both make about the same ft/lb of torque, but the GSR, is able to stay in gear longer, do to its higher redline.

 

I don't know if I understand your point. A high redline only has an effect as far as staying in gear longer for 1st gear. Even then it mainly depends on how short or tall 1st gear is

after that, how long you stay in each gear completely depends on the gear ratios and how many gears. If it's a 6 speed close ratio tranny, each gear will be short and you'll mainly hover in the upper powerband. With a 4 or 5 speed tranny, you'll actually drop to the mid rpms after each gear shift. In that case each gear will last longer. Usually big engines work best with fewer gears because they pull lots of power/torque in the midrange anyway (much the same like the mid sized turbos for the Z on most kits)

we can't really compare 1/4 mile times between different cars with different engines because there's other factors involved like weight, aero dynamics, weight distribution etc

all 3 engines can have the same displacement, but different cams, intake manifold, aluminum/titanium/steel engine parts, different heads, compression ratio etc to make each one radically different from each other


things get messy with trying to find before/after dynos of stroker kits by themselves because people usually do headwork and cams if they're going to the trouble of spending big money on a stroker kit in the first place

 

The gearing is nearly identical.

 

but are the heads, cam profiles, intake and exhaust manifolds, exhaust, materials, and compression ratio identical?

They can't be otherwise it'd be the same engine

 

There is a reason why AMS, John Shepard(evos for that matter), mr2's etc.... have the fastest times, with a destroked or factory displacement for that matter. Its still not proven, that becuase you have a stroked out 4.3 liter VQ motor opposed to a stock displacement motor with an identical setup, is more beneficial.

There are plenty of people that make more torque than hp on these forums, without the benefit of a stroker.

 

the reason the people make more tq than hp (probably all turbo, nitrous, or possibly stillen SC people) is because the 3.5 liter VQ is the most efficient at around 4500 rpms. Actually most engines are at their highest efficiency at mid rpms except for cars that have variable cams like Vtec where the cam profile changes to also make the upper end fairly efficient.

Anyway, if you had a normal engine and you add 8 lbs of boost at 4500 rpms you get more tq at that rpm than you do in the upper rpm where the engine is not as efficient


the reason some cars destroke their engines is because they decided they want to rev the car even higher. Bigger engines don't like to rev as fast as smaller engines and run into mechanical limitations much sooner and build up heat more because there's more metal surface area heating up.


F1 race cars don't make much torque at all. They rev to 20k rpms and so with a small amount of torque they're able to do that small torque so frequent that they end up making like 700-800 hp

 

There is a reason why AMS, John Shepard(evos for that matter), mr2's etc.... have the fastest times, with a destroked or factory displacement for that matter. Its still not proven, that becuase you have a stroked out 4.3 liter VQ motor opposed to a stock displacement motor with an identical setup, is more beneficial.

There are plenty of people that make more torque than hp on these forums, without the benefit of a stroker. Alot of the power and torque are the benefits of higher compression(which I think is more beneficial than stroking)