What has greater power range

[silkcity100]

we will all find out soon if a stroker with stage4 cams and gt35r could have more powerband then a 2.0,just got some custom brackets to fab up for the oil cooler and tuning left

 

[Tom N]

we will all find out soon if a stroker with stage4 cams and gt35r could have more powerband then a 2.0,just got some custom brackets to fab up for the oil cooler and tuning left

You mean you will know.
Most people already know.
Incase you didnt know the FP4 cams are smaller than FP3x cams.

 

[Tom N]

you mean the 3x cams are bigger than the 4 cams.

yes.

 

[Rick@AP]

The problem with this discussion is that everyone is concerned with peak power and not power under the curve.

 

[Tom N]

The problem with this discussion is that everyone is concerned with peak power and not power under the curve.

Say it again.

 

[silkcity100]

can someone show me a dyno graph on a setup that has a stroker engine ,cams,and gt35r

 

[silkcity100]

theres a lot of 2.0`s with cams n gt35r,but havent seen any with a stroker,anyone have a link or photo of dyno graph

 

[Turbocharged]

The closest thing I could find was an 2.25L evo:

http://forums.evolutionm.net/showthread.php?t=174231

The car overran the walbro fuel pump on the dyno.

Shane has been running a 2.4 for some time now; check out his dyno sheets:

http://www.dsmtuners.com/forums/member.php?find=lastposter&t=9244

I think this dyno illustrates that a 2.4 can breath over a wide range of rpms.

 

[Rick@AP]

can someone show me a dyno graph on a setup that has a stroker engine ,cams,and gt35r

http://www.dsmtuners.com/forums/attachment.php?attachmentid=64753&stc=1&d=1150138259

Fresh built 2.3l (less than 20 mi.), cams, and a gt35r at a measly 18-19 psi.

This dyno is a great example of what you get when you properly match the intake, exhaust and cam for the engine size.

 

[Turbocharged]

http://www.dsmtuners.com/forums/attachment.php?attachmentid=64753&stc=1&d=1150138259

Fresh built 2.3l (less than 20 mi.), cams, and a gt35r at a measly 18-19 psi.

This dyno is a great example of what you get when you properly match the intake, exhaust and cam for the engine size.

Do you have more information on this car? What cams, ect? Im interested in a bigger turbo and would like to compare some dyno sheets.

 

[Rick@AP]

Do you have more information on this car? What cams, ect? Im interested in a bigger turbo and would like to compare some dyno sheets.

FP3x cams, full race manifold, magnus intake, gt35r, large precision front mount, 1150cc injectors, that's about all I remember.

For your 2.4l I would suggest:

Bolt on: FP3575

w/aftermarket manifold: GT37 or GT40, with divided turbine housing

If you already have the FP3065 the GT35r is a sidestep with a slight step up.

 

[steel_3d]

Sorry to interject, just wanted to share what I found from some simulations on DesktopDyno. Same setup, all I changed was the stroke length from 88 to 100mm. The darker lines are photoshopped over the original by me, and they represent the stroker's curves.

<a href="http://i6.tinypic.com/1zcmhch.gif">Graph</a>
<a href="http://i6.tinypic.com/1zcmjhe.gif">Table</a>

The table shows how the VE curve of the stroker is shifted down by several hundred rpm compared to the 2.0.

Using larger cams, freer intake/exhaust, etc, lets the stroker hang on longer, but the 2.0 ultimately wins at high rpms. Unfortunately the cheap version I have doesn't let me graph past 8500rpm. If I paid double I could calculate area under the curve too, but again, I'm cheap It's pretty obvious the 2.0's gonna win that battle if you let it rev 15% longer than the stroker. Revving both to 8500 in this scenario: the stroker wins. Again, it all depends on what you wanna do with your setup.

Of course this is a simulation, so take it with a grain of salt.

 

[Rick@AP]

Desktop Dyno 2000, which is what I am assuming you are using, is a shi**y program. I can make a Honda produce 1000 hp by 2k rpms with that program.

If you want proof, take the data that I gave you from the dyno posted above and loaded it in, then compare the real world graph with what it outputs.

 

[steel_3d]

I know the absolute numbers don't mean shit in this program. Individual changes make a bit more sense. I figured a stroke change is relatively simple to simulate. The results look plausible based on our previous back of the envelope calculations, so I posted it as an extra piece of info. Again, take it with a grain of salt.

I know the program's not the best (it's the latest "sport compact" version). In fact I'm gonna email those assholes with all the stupid shit it outputs. Forget about trying to simulate different turbos. A 14b at 26psi makes almost the same power as a "t04e super-60" (whatevertf that is), but it's laggy as hell . A lot of the graphs it outputs are stupid looking with weird peaks and dips. Anyways, the stroke change looked reasonable so I posted it. Read into it what you will...

 

[nightspeed87]

so what im learning from this, is the longer the stroke and size the longer it takes to rotate, more power during this, but it cant spin up the engine as fast, and a smaller stroked engine can rev higher but make less power for each stroke.
But at the higher rpm of the 2.0 its making approx. the same power as the stroker at the lower rpm, so therefore stroker is more effiecient at lower rpms and intial power band, ( better for awd) but at higher rpms 2.0 wins but disadvantage it takes longer to get the rpm higher so therefore the 2.0 will take a little longer to get to its power band at the same power as the stroker for the same power levels.

( Plus someone wanting to rev beyond 8 thousand rpms will need better tranny, cams, cam gears, valves, etc. )
I.E. built up small honda engines revving so fast and high with powerband up high. opposed to a v8 making power early in the band but the band being shorter, and it all depends on the type of racing your doing to what style you want correct.? So its a catch 22.... Is that about right??

 

[srumel]

after 4 pages, i found out that i don't have a.d.d. yay!

 

[steel_3d]

Just to keep the argument complete, here's another bit of info I posted on <a href="http://www.teamnabr.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=005643">nabr</a>.

It seems I was wrong on another point. The rpm capability of a stroker (as far as piston acceleration goes) seems to be only about 3.3% lower than that of a 2.0, not 13.6%, as I falsely assumed before. This means the intertial force on a 2.0 piston at TDC at 10330rpm is the same as the stroker at 10000rpm. This is the force of the piston trying to rip the rod apart at TDC on the intake stroke.

I was using the equations from Wiseco's tech tips presentation: http://www.wiseco.com/TechTips.aspx. I was using Wiseco piston assembly weights (stroker pistons are lighter). I factored in the effect of the rod/stroke ratio too, as shown in the slides.

The point is that by rearranging the equations (after equating the TDC force of the two setups), it seems the rpm capability decreses as the square root of the stroke increase, so for a 13.6% increase in stroke the rpm capability decreses only by ~7%. The lower weight of the stroker pistons helps their case too in addition to this. With a 10% lighter piston assembly, the stroker's rpm capability is only 1.8% lower than that of a 2.0. The rod/stroke ratio works against strokers, but that only accounts for a 1.5% decrease in rpm capability. 1.8% * 1.5% = 3.3%.

This begs the question of why are strokers (perceived to be) so much less reliable?

 

[PieEyedPiper]

Just to keep the argument complete, here's another bit of info I posted on <a href="http://www.teamnabr.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=6;t=005643">nabr</a>.

It seems I was wrong on another point. The rpm capability of a stroker (as far as piston acceleration goes) seems to be only about 3.3% lower than that of a 2.0, not 13.6%, as I falsely assumed before. This means the intertial force on a 2.0 piston at TDC at 10330rpm is the same as the stroker at 10000rpm. This is the force of the piston trying to rip the rod apart at TDC on the intake stroke.

I was using the equations from Wiseco's tech tips presentation: http://www.wiseco.com/TechTips.aspx. I was using Wiseco piston assembly weights (stroker pistons are lighter). I factored in the effect of the rod/stroke ratio too, as shown in the slides.

The point is that by rearranging the equations (after equating the TDC force of the two setups), it seems the rpm capability decreses as the square root of the stroke increase, so for a 13.6% increase in stroke the rpm capability decreses only by ~7%. The lower weight of the stroker pistons helps their case too in addition to this. With a 10% lighter piston assembly, the stroker's rpm capability is only 1.8% lower than that of a 2.0. The rod/stroke ratio works against strokers, but that only accounts for a 1.5% decrease in rpm capability. 1.8% * 1.5% = 3.3%.

This begs the question of why are strokers (perceived to be) so much less reliable?

Maybe one of our vendors could chime in. Since they happen to make these engines and would mostly likely know mroe than just what we can speculate.

 

[pneumo]

I searched this thread for 'windage' and came up with empty. Do any of the engine modeling programs allow changes based on an engines internal air resistance? It would be interesting to see the results of comparing a 2.0 motor at low and high rpm, then a stroker motor at low and high rpm. I know that air resistance goes up at twice the change in speed, but I don't know if windage produces significant drag when compared to other internal engine losses. A longer stroke churning through an air/oil mix must produce more drag, but how much?

I did a quick test tonight. I was driving at about 40mph and noticed the readout on my SAFC showed 95 Hz worth of airflow. Then I pushed in the clutch and raised the rpms until the SAFC showed 95 Hz again. I was spinning the engine with no load and it stabilized at 3500rpm. So the power required to push my car at 40mph is the same as the power used just to turn the engine at 3500 rpm. Somehow I thought it would rev higher. I'll try it again tomorow and see what happens at higher speeds.

 

[94awdcoupe]

This thread hurts to read. What you guys should be looking for are some good back to back comparisons. There is such a comparison at evolutionm and it comes from one of the most respected tuners in the US, david buschur. He tuned two cars with identical setups at his shop with the only difference being the 2.3 shortblock in one car. These cars where setup on AEM and 35R. The 2.3 setup made 60tq and 30hp more than the 2.0. Now keep in mind dave up until this comparison was completely sold on 2.0 as a better choice for a high powered car. This argument over which is better is VERY turbo dependant. When larger turbos are used higher rpms are needed to reap the flow. RPM bands need to be in the 6-10,000rpm range to make power with 40r,42r and 45r turbos. Strokers don't breath as well as 2.0s at those rpms so the shorter stroke/smaller displacment becomes a better choice. The whole arguement that all the fastest in the country are on 2.0 liters is all fine and dandy but you need to know that all those cars are running turbos much larger than 35r size turbos. If you were to compile a study of comparisons of just 35r track times you would see for that sized turbo and anything smaller you will go faster at the track on the 2.3/2.4 setups, and the car will be much more fun to drive as the faster spool of a stroker is much more enjoyable. The 3575 and 67mm turbos are getting into the crossover point on which would be a better choice.

 

[steel_3d]

This thread hurts to read. What you guys should be looking for are some good back to back comparisons. There is such a comparison at evolutionm and it comes from one of the most respected tuners in the US, david buschur. He tuned two cars with identical setups at his shop with the only difference being the 2.3 shortblock in one car. These cars where setup on AEM and 35R. The 2.3 setup made 60tq and 30hp more than the 2.0. Now keep in mind dave up until this comparison was completely sold on 2.0 as a better choice for a high powered car.

Can you post a link, I can't seem to find that post on evolutionm.net.

This argument over which is better is VERY turbo dependant. When larger turbos are used higher rpms are needed to reap the flow. RPM bands need to be in the 6-10,000rpm range to make power with 40r,42r and 45r turbos. Strokers don't breath as well as 2.0s at those rpms so the shorter stroke/smaller displacment becomes a better choice.

This is not true, at least not the way you phrased it. Put a 42r on a 6 liter v8, and you won't have to spin it to 10k to make more power than a 2.0 inline 4. It's got nothing to do with rpm's per se. It's got to do with displacement and volumetric efficiency. A stroker will flow more air at 10k rpm than a 2.0. It just might not make more power due to the decreased cylinder pressure, as described in <a href ="http://www.dsmtuners.com/forums/showpost.php?p=50419543&postcount=83">this post</a>.

If you were able to open up the head, intake and exhaust to raise the VE of the stroker enough, it can come out ahead, and at lower rpms. Not sure where the flow limits of the 4g63 head are, which decides whether this is possible.

 

[pneumo]

Like I promised, I did another quick experiment today. Cruising on the freeway at 65mph uses 165Hz worth of airflow and 12% throttle. Then I free revved the engine at 12% throttle and 165Hz and the rpms stabilized at 5200 rpm. That's a good chunk of power just to spin the motor. This is with a 2.0 motor and a stock 2G maf.

The reason I'm posting this is to highlight one area of power loss at high rpms. Windage losses might be a smaller issue on the 2.0, but they're more significant on a stroker looking to go to higher revs. To reduce these losses crank baffles can be used, FFWD connection has a nice Butcher crank, or go all out and build a dry sump kit. The idea is to find supporting mods that fit the motor and it's intended use. It's something to think about if anyone out there is building a badazz stroker motor. It's only one piece of the puzzle, but it might just improve it's range

 

[1gcrazy]

So what about my 2.1 destroked motor i'm building? Does that give me the best of both scenarios? Or a compromise, more or less. They're 2.1's and they rev to the moon. If you're going to put all that money into a 2.3/2.4 then why slack on the valvetrain?

Just curious where my 2.1 stacks up against the 2.0 and 2.3/2.4.

 

[1gcrazy]

Your 2.1 is basically a bigger bore 2.0, with a taller deck and longer rods.

Well I understand THAT. I was curious if it were a compromise between the two engines? Its a high revver and its got increased displacement. Is this engine a better choice over a 2.0 or 2.4? I'm looking to rev it high but it's mostly a street car. Occational drags. Big turbo of coarse.

 

[pneumo]

Another advantage to the larger bore of the 2.1 and 2.4 motors is the extra room between the valves and the cylinder bore. The bigger bore gives you room to unshroud the valves, and make more room for oversize valves. This only helps if you gasket match the cylinder head to the combustion chamber. Otherwise the edges of the combustion chamber overhang the bore slightly, producing a sharp edge and a potential hotspot.