What has greater power range

[Tom N]

When a stroker runs 8`s or better and can rev over 10k rpms and still make huge power then I will look at one.
There is a reason that all the fastest DSM`s run high reving 2.0ltrs.

 

[Tom N]

Are you saying none of the fastest dsm`s run strokers because of traction issues???
You really think Brent Rau has bad traction issues.
You are nuts if you think Shep or anyone else is going to give up being able to rev over 11k rpm`s for more bottom end.
More bottom end is fine for the street but the ability to rev to the moon is what wins on the 1/4 mile.

 

[Turbocharged]

Personally, I dont want a sub 10 second car for my daily driver. I enjoy being able to pass people with ease on the highway at 3k rpms while in 5th gear.

And yes, a 2.3/2.4 does cause some traction issues at the track, sometimes even on the street. My first time going WOT was on an entrance ramp. Once boost hit, I spun my tires across two lanes. Once they caught traction, I was pointing toward a retaining wall; it was scary to say the least.

Both are great motors. If you are only going to see the track, build a 2.0. If you will be driving your car to the track, build a 2.3/2.4.

And yes, a longer stroke equals more torque. In fact, I disagree with just about everything that bwhughey has stated.

http://auto.howstuffworks.com/question381.htm

A g4cs/4g64 (86.5mm x 100mm) has a similar bore and stroke as an srt4 (87.5mm x 101mm). The srt4 redlines at 6750 and has gone faster than 10 seconds. Im sure a g4cs powered dsm could do so as well.

 

[graf703]

And yes, a 2.3/2.4 does cause some traction issues at the track, sometimes even on the street. My first time going WOT was on an entrance ramp. Once boost hit, I spun my tires across two lanes. Once they caught traction, I was pointing toward a retaining wall; it was scary to say the least.

.

Think of letting off ever?

 

[Lottaboost]

I'm more for the 2.3 untill you start getting into the real large turbos.

With a 2.0 and a real large turbo (T-67 and up type range) you can use the power band a little better by haveing more RPM's in full boost.

Think about it. If you have a 2.3 and a huge turbo and full boost for example comes in at 5000 and you have to shift at 7.5 then you only have about 2.5K under full boost to play with.

If you have the 2.0 and it has full boost at 6 and you shift around 9-10K (full race engine)
then you have 3 to 4K under full boost.

KEEP IN MIND THIS IS JUST AN EXTREME EXAMPLE but it still makes the point.

My street car is a 2.3 with a GT35R and it is a blast to drive
If I had a track only car it would be a 2.0 with either a GT40R or a GT42R.

 

[TT_NS]

this obviously means to me that i should run the 2.0 with a FP3575

 

[Ultimatedsm]

There is no replacement for displacement . You will get wayyy more low end torque compared to a 2.0L. Sure you will have lets say 1000RPM more on the 2.0L to play with, but the massive torque the 2.3L produces adds up to be more than 1000RPM of more play . You don't need high revs for a 2.3L engine, it has a lot more grunt at the lower rpms. Remember torque gets you out of the hole.

 

[steel_3d]

Lottaboost, you missed my first point, and all my other points.
If you can build a 2.0 to spin to 10k, you can build a stroker to spin over 7.5k. Again, that's a safe daily driver redline. People have gone 9k-9.5k on strokers with not much modification (mostly free mods). See Kiggly. Now, will you take 5k-9k or 6k-10k. Considering that the stroker is making more torque in that rage.

I just did some calculations with a flat torque curve of 400lbft for the 2.0L and 25% more for the 2.3L = 500lbft (more conservative than the theoretical 30% advantage). The 2.0 is making 761hp@10k rpm and the 2.3 is making 857@9k. The 2.3 has almost 10% more area under the curve in that 4k rpm range.

The numbers can be played with all day, but it's hard to make the stroker lose. If you limit the stroker to the same pistons speed as the 2.0 at 10k, you get 8.8k, and in that case the stroker only wins by ~2%. But since others have spun to 9.5k, why shuldn't you spin to 9k?

In my mind there's no disadvantage to the stroker, no matter what turbo you run, in fact it can be faster if you build it right. I think the reason they're not at the top in the real world of drag racing is the fact that they're not as common -> less development, but mostly because even the guys who try it go running back because they're breaking drivelines all over the place.

As I said before, how you handle the torque, or whether you like breaking cranks is up to you. The original question was concerning the *power band* of the two combos, and I think the stroker is fine for drag racing from that point of view.

 

[Tom N]

Absolutely. These ares are already pretty light once their under the race spotlight.

So Brent Rau is having really bad traction issues with his 1.0 60fts.
Most of these guys make around 1000hp or better.
They run 2.0ltr because they are better. Not because of traction issues.

 

[dalatinromeo]

So Brent Rau is having really bad traction issues with his 1.0 60fts.
Most of these guys make around 1000hp or better.
They run 2.0ltr because they are better. Not because of traction issues.

I have to agree with what 90tsiawd is saying in this entire thread.

I am not knocking the stroker, because they are fun to drive and have awesome torque; but when you look at the fastest dsm's out there, they are 2.0 not the 2.3/2.4 strokers.

Stay boostin

 

[steel_3d]

Anyone know roughy what does guys are revving to?

I will contend that short stroke wins if you rev it to the moon (see F1). My argument was against the people who were throwing the 2.0's 10k rev limit around. If you're gonna go beyond that, it's a different story. Most people can't afford to because of valvetrain limitations mostly. I'll agree that the stroker might self-destruct before the 2.0 when it's pushed to the limit of the bottom end, because it does have structural disadvantages which *might* outweigh the lever-arm advantage. Right now I don't think anyone can say what the structural limit of the stroker is. But if you're not going for absolute ultimate Pro RWD class leading power, the stroker has potential to be better.

 

[Tom N]

Ok so how many 9sec or better strokers are there???

 

[pboglio]

A 2.0L short stroke motor also arguably offers better high rpm torque, presumably due to less piston ring friction drag losses among other things. Just for kicks I ran a little comparison on Desktop dyno 2000 between our 2.0L short stroke and 2.3L or 2.4L long stroke Mitsu motors. Sure enough, the 2.0 Liter motor produces MORE torque starting at roughly 5800-6000 rpm and walking away pretty good from the stroker motor above that. The guys that wrote the software even tell you to run short stroke/long stroke comparison as a tuturial to illustrate the high rpm torque drop off of the long stroke motor. Its a computer engine simulation, but it does get you thinking.

 

[turbodagain]

A 2.0L short stroke motor also arguably offers better high rpm torque, presumably due to less piston ring friction drag losses among other things. Just for kicks I ran a little comparison on Desktop dyno 2000 between our 2.0L short stroke and 2.3L or 2.4L long stroke Mitsu motors. Sure enough, the 2.0 Liter motor produces MORE torque starting at roughly 5800-6000 rpm and walking away pretty good from the stroker motor above that. The guys that wrote the software even tell you to run short stroke/long stroke comparison as a tuturial to illustrate the high rpm torque drop off of the long stroke motor. Its a computer engine simulation, but it does get you thinking.

The main reason the 2.0 offers better high rpm torque, is that for the same rpm, the piston speed is slower, thus giving more time to fill the cylinder during the intake stroke.

Most people only mention piston spead when is comes to determing the rpm limits of a motor. But the piston speed plays a critical role in the volumetric efficiency of the motor. Piston speed is the reason for torque drop off at high rpm in all piston motors. There is basically less time available to fill the cyilnder to put it simply.

The increased displacment, and crank leverage, give the stroker the advantage at lower to mid rpm. But once you get into high rpm, the higher piston speed for the same rpm, make the stroker motor run out of breath....

 

[Turbocharged]

But once you get into high rpm, the higher piston speed for the same rpm, make the stroker motor run out of breath....

Thats why they designed cams like the FP3/4. These motors respond very well to being cammed for the reasons you mentioned.

http://www.dsmtuners.com/forums/showthread.php?t=183700&highlight=fp2+fp3

My 2.4 gained power over the entire rpm band after swapping in FP2's.

 

[steel_3d]

The increased displacment, and crank leverage, give the stroker the advantage at lower to mid rpm. But once you get into high rpm, the higher piston speed for the same rpm, make the stroker motor run out of breath....

I somewhat underestimated the high-rpm effects. I never thought of the friction factor at all.

What we need to realize is that the above statement doesn't mean the stroker can ever have a lower torque value *at a given rpm* than a 2.0. Rpm for rpm the stroker has no way of taking in LESS air than a 2.0. It may take in less than 20% more, might be 15%, 10%, or just 0.1% more, but it will still take in more air. And it still has the leverage advantage. It does throw a bit of a wrench in my previous calculations, because I incorporated a constant fudge factor (taking a 20% overall advantage for the stroker /rpm vs the ideal 30%). Obviously nothing beats a real simulation.

Now, you mention piston speed, but we know we don't spin the stroker to the same rpm as the 2.0. We spin it to a 13.6% lower rpm, at which point it has *the same* piston speed as the 2.0, so the volumetric efficiency should be about the same in the usable rpm range, right? Plus you can help it more with cams, as it has been stated before.

The friction effect that pboglio was talking about is the only plausible reason for the stroker to have a lower torue at a given rpm than the 2.0, not piston speed. Don't different rings (like chrome-moly, different face profiles) have different friction characteristics? Kinda pissed now that I'm putting oldskool flat-faced iron rings in my stroker It's possible that they overestimated the friction factor in the simulation.

I wonder if there are other rpm based effects that increase with a longer stroke... It seems that moving the pistons a longer distance requires more work. Work = force * distance, and force = mass * acceleration. So work = mass * acceleration * diatance. In a stroker both acceleration (average) and distance increase. Having to do this extra work would suck up power. I don't feel like calculating how significant this is. I can't get it straight in my head though whether this is recovered on the compression stroke... Probably not.

I give up. I can't do an engine simulation in my head. If we trust the simulation program that pboglio was using, then you short stroke guys win, and my answer to the original poster has to change to "The 2.0 has more area under the curve".

 

[turbodagain]

I somewhat underestimated the high-rpm effects. I never thought of the friction factor at all.

What we need to realize is that the above statement doesn't mean the stroker can ever have a lower torque value *at a given rpm* than a 2.0. Rpm for rpm the stroker has no way of taking in LESS air than a 2.0. It may take in less than 20% more, but it will still take more. And it still has the leverage advantage. It does throw a bit of a wrench in my previous calculations, because I incorporated a constant fudge factor (taking a 20% overall advantage for the stroker /rpm vs the ideal 30%). Obviously nothing beats a real simulation.

.

The increased displacment and leverage advantage, are definately advantages, but at some point, there side effect, Higher piston speed, overweighs the benefits, and the 2.0 is making more power. At high rpm, there is no way it is taking, all the extra 15 percent of displacment. In fact, if for the same rpm the 2.0 is making more power, you can clearly see the 2.0 is taking in more air/fuel.

 

[Slippi84]

Exactly>>

The point of this thread is moot, anyone who can do math, can tell you that a stroked motor, (racing sense) is a completely better motor in every aspect.

When people want to race their car, fine, take a 2.0 and plop on the rpms. But if your going just complete all out, you already know that bigger is better, and bigger + FI is even better. Regardless at how you look at it, it is a completely better motor, and not just for a tube frame with 40ft drag radials.

People are already taking their 2.3s to 9k, as its already been stated time and time again.

To answer the thread, the 2.3 has a 15% higher power range than a 2.0.

Sure you have 3k to spend on internal PARTS(pistons, rings, rods) alone to get the stuff good enough just to rev that high sure you can rev to 9k in a stroker

This seems to be the argument flavor of the month it was bolt on housings now it's strokers vs 2.0ls. Everyone saying that well this engine because of this should do this and be better because of this doesn't have real world experience. The fastest guys use a 2.0l. Say what you want but it's as simple as that. I know not the same type of car and yada yada yada but if the stroker was so much better than why isn't the HP list or the 1/4 mile list flooded with them cause those guys have the money to do it and the knowledge ?????

 

[Tom N]

Sure you have 3k to spend on internal PARTS(pistons, rings, rods) alone to get the stuff good enough just to rev that high sure you can rev to 9k in a stroker

This seems to be the argument flavor of the month it was bolt on housings now it's strokers vs 2.0ls. Everyone saying that well this engine because of this should do this and be better because of this doesn't have real world experience. The fastest guys use a 2.0l. Say what you want but it's as simple as that. I know not the same type of car and yada yada yada but if the stroker was so much better than why isn't the HP list or the 1/4 mile list flooded with them cause those guys have the money to do it and the knowledge ?????

Can`t get any more simple than that.

 

[steel_3d]

In fact, if for the same rpm the 2.0 is making more power, you can clearly see the 2.0 is taking in more air/fuel.

That is precisely NOT the case, that's why I wrote the above post Airflow and hp are not directly related. There are many factors that influence hp/airflow. Compression, leverage, and now friction and possibly the work of moving the piston further and accelerating it faster. It's the last two that seem to prevail in the simulation that pboglio quoted.

Again, the 2.0 can not consume less air than a stroker at a given rpm. It's a simple fact that the stroker creates a larger vacuum, which can't be filled with less air than before. It's always gonna be a little more. The time to fill it is the same, the vacuum is larger, everything else is the same. No way it will suck in less.

You guys keep talking about piston speed. Think about what happens if the piston speed of the stroker is infinite. Will it suck in 0 air, or any less air than a 2.0?

Now think about what happens if you have a large bore engine with the same stroke as the 2.0, but its volume is 2.4L. Will it suck in air any more efficiently than a stroker? No, except for the marginal effects of piston dwell and such (I'm not even sure if that matters in this case).

What you guys are thinking of is relative volumetric efficiency. Yes, the volumetric efficiency of the 2.0 is better at a given rpm, since the 2.4 has to try to suck more through the same little straw. But the volumetric efficiency doesn't decrease enough as to completely offset the displacement advantage or go negative, not to mention the leverage advantage. In addition, the volumetric efficiency of the stroker is about the same 13.6% lower in the rpm band as the 2.0.

 

[steel_3d]

Well if you guys were listening you would know that we're all learning from this thread. pboglio offered a plausible reason why strokers are not so superior after all. I'm willing to listen to logic. There's no point in you guys repeating that noone's in the 6's with a stroker 4g63, unless you have some sort of reasoning as to why that's the case.

 

[turbodagain]

The time to fill it is the same, the vacuum is larger, everything else is the same. No way it will suck in less.

The time to fill is not the same, at the same rpm between the 2.0 and 2.3

Sure the larger displacement, creates more vacuum during the intake stroke, but at the same rpm, the strokers piston speed will be higher, and this less time, it what causes it not to inhale the same as the 2.0


This is why the 2.0 is more capable at high rpm.

and yes if you had a large bore, small stroke 2.4 it would definately make more hp, If everything else is the same , as a long stroke 2.4

 

[steel_3d]

The time to fill is not the same, at the same rpm between the 2.0 and 2.3

Ahhahaha.. I'm getting tired...

6000rpm = 100 rotations per second. Therefore the cylinder has half a hundredth (half because the intake stroke lasts for half a revolution) or 5 thousandths of a second time to fill. It don't matter what yo stroke is.

You should read what people write. I don't mind explaining shit, but I already explained the same thing from 15 different angles. My style sucks ass so you might have to read it over twice.

Again, think of what happens if you have INFINTE piston speed. In an instant the piston is at the bottom of the cylinder, creating a vacuum. This vacuum lasts for 5 miliseconds (@6000rpm). The intake valve is open during this time. Are you gonna get 0 air in the cylinder, just because your piston speed is infinite?

 

[T2Small]

The time to fill is not the same, at the same rpm between the 2.0 and 2.3

Sure the larger displacement, creates more vacuum during the intake stroke, but at the same rpm, the strokers piston speed will be higher, and this less time, it what causes it not to inhale the same as the 2.0

Please explain why there is less cylinder filling *time* with two different displacement motors running at the exact same RPM assuming they are both 4 stroke engines and have exact same cam profiles and rocker ratios?

I will agree that it can take more time to fill a larger volume from a fixed sized intake ports with the same cam profiles and rocker ratios. However, I don't see how it is all possible for the 2.4 to receive less total volume. At very worst it will receive only marginally more than a 2.0 and a lower percentage fill.

Why is everyone assuming that no one fast runs a 2.4 or some sort of stroked motor? I am fairly confident that many of the fast guys give little or no details on the motors they run. I suspect that some are running different parts and combinations than we think.

I am 100% confident that a 2.4 can and will equal or outflow a 2.0 motor at the same RPM. (I will not gaurantee that the 2.4 bottom end will survive the same RPM without extra precautions being taken on the 2.4.)

 

[Turbocharged]

The price difference between a built 2.4 and a built 2.0 is negligible. I speak from experience as I have done both builds. The only difference was that I had to buy 2.4 cam sprockets and I needed a custom head gasket from cometic because of excessive cylinder chamfer ($139). The cost of all other respective parts was the same. If you already have a 6 bolt equipped 1g, a 2.0 build will be cheaper for you.