the 2.1 strocker/destrocker

[DeeBo]

so i been trying to find out whats the deal with the 2.1 but i have yet to find anything about it yet... anyway i was wondering is there a site or thread about it and how its built becuse i like the idea of reving to 10k+ rpm

thanx
deebo

 

[brute]

If you're going to be revving that high, expect a motor that won't live too long.

With 2.3 and 2.4L strokers, the regular-length rod is used, but a shorter (height) piston. This creates more stroke, and more displacement.

However, with the 2.1L, they use long rods with the shorter pistons. This makes for a little more than stock displacement (0.1L).

This is from Slowboy:

What makes a long rod work? There are many advantages to stepping up to a long rod motor over stock or certain types of strokers. A longer rod actually reduces rod angle overall so when measured in degrees, less are observed which reduces stress from vertical and horizontal impulses. During the firing portion of the stroke, the angle of longer rod is lessened over the standard length rod. Longer rods result in slower piston speed at the top and bottom of the stroke reducing bearing wear and wrist pin stress throughout the stroke. Nevertheless, lower piston speed at the bottom of the stroke is where forced induction motors benefit the most in that the ports have more time to be crammed full of pressured air over the same port filling time when compared to a standard length rod motor.

 

[andymoraitis]

so i been trying to find out whats the deal with the 2.1 but i have yet to find anything about it yet... anyway i was wondering is there a site or thread about it and how its built becuse i like the idea of reving to 10k+ rpm

Revving to 10K is about much more than building a de-stroked 2.1. You'll need a valvetrain that will handle it, cams that will breathe, a turbo that will flow and a transmission that can be shifted at high RPM. You're looking at spending a pretty penny for something that's better suited to a dedicated race car.

I'd spend your money elsewhere.

Andy

 

[Kevin Jewer]

I don't believe short pistons are used on destroked motors. In fact it appears that they are not. The reduced stroke comes from using a 2 liter crank, the regular pistons can be used becuase of the taller 2.4 liter block, and the extra displacement comes from the larger bore of that block.

I find the 2.1 to be very interesting. No one says you have to take it to 10k rpm. You could rev to 9k RPM knowing that you are not abusing the motor as much as you would be a 2 liter. Or you could rev to 8k like most poeple and simply enjoy the extra .14 displacement, which is half of what you get with a stroker without the limitations and sideloading on the short pistons. The valve train is easy to upgrade, the tranny is the only worry IMO. And most Shep trans can do 9k rpm. Just thinking out loud...

As far as making one work, the internals are a no brainer, and getting this block to work in our cars with our heads is no different than running a "full" 2.4, for which there is plenty of info available.

I do agree with Andy that this is not a "mod" that you would add to your mod list. It's best suited to people that are doing a full build up anyway, and this fits the theme of thier particular build.

 

[andymoraitis]

Good info in there Kevin. Thanks for sharing more of the gritty details than I was able to.

 

[weith1111]

What is a "strocker" anyway?





I can't wait to see if this motor picks up popularity like the 2.3/2.4 did. I remember planning a rebuild with a 2.4 years ago and was told it was too risky and people didn't know what they were doing, so I should wait until it was more proven as only a couple people had success so far.

This seems like it would be a good motor for short track racing, maybe autocrossing even? Paired with the right turbo it could be a killer setup to be able to run 6-9k rpms all day and have the motor and turbo in happy places. Just thinking out loud too...

 

[slipstream808]

First off, its a "stroker" not a "strocker".

It comes from the the truth - in the end there really is no true replacement for displacement. You can up the boost and things will work in a different way and tune things (we wont worry about that it's a huge-booty discussion), but in the end, ideal setups for each, both running 20 psi, a 3.0L will get you more output than a 2.0L. So more displacement is better (especially in a lower RPM street driven car).

For us though, more displacement will spool up a bigger turbo sooner meaning its more "streetable".

So how do we up the displacement? Bore refers to the size around of the cylinder. Stroke refers to the ditance the piston travels. Upping either one will increase displacement. Well, boring out a 4g63 is pretty much out of the question because Mitsubishi gave us a good leg-up from the factory. The 46g4!! It has a larger diameter crankshaft, which when combined with normal rods and shorter pistons, will give you a better displacement based on the increased stroke. Hence the term "stroker".

 

[UofACATS]

For us though, more displacement will spool up a bigger turbo sooner meaning its more "streetable".

Not to mention the increased off-boost power..

 

[JOEY A]

Why do people think they need to rev the ever living piss outta motors? If you reving to 10K you better have a GT42R or somthing along those lines.

I mean it does like to rev, but so does a 2.0 so why do people think they must rev a 2.1 that high?! You have a street car, build a 2.1,2.3,2.4 for more TQ and response. If want 10K go buy a honda.........


Show me one STREET CAR, not a weekend or some bullshit ass street driven race car that revs that high makes power and is usable.


I mean a Real EVERY SINGEL DAY car that is reving to 10K!?!?? I highly doubt alot of people are running around like that.

 

[JOEY A]

I wanted to do a 2.1 and stay with my EVOIII now that would be a killer street setup but costs got into it.

So I just did the Weisco 9:1 with eagle rods, should make good off boost response.

 

[andymoraitis]

I wanted to do a 2.1 and stay with my EVOIII now that would be a killer street setup but costs got into it.

So I just did the Weisco 9:1 with eagle rods, should make good off boost response.

You're contradicting yourself. In the post above you mention that you'd want a larger turbo if you were going to run high RPM, but you were thinking of doing this with an EVO III and a 2.1? Doesn't make much sense to me. That EVO would be clawing for breath well before 10,000 RPM and the motor would be outflowing it beyond belief.

Also, bumping compression up from 7.8:1 to 9:1 doesn't do much, if anything for off boost response. Read posts 7 and 9 from this thread:

http://www.dsmtuners.com/forums/showthread.php?t=224002

Displacement is what makes the big difference.

 

[DJpHGotBanned]

Andy, your explanation does not make much sense. A Evo3 turbo can be used and wont necessarily be over taxed with the higher RPM. This isnt a belt driven supercharger. Turbos dont care what RPMs the motor turns. They only care about CFM. Now if you rev your engine at a boost which equates to more CFM than the Evo3 turbo can handle, then you will start to have issues.

It would be silly to use a small turbo in this case though. Sure you could spool it up by 2500rpm and use it until 7500rpm over a 5000rpm range, but you've dont NEED to. You could use a BIG turbo and spool it at 5000rpm and spin the engine to 10,000rpm over an equal 5000rpm band, but with MUCH more CFM available and MUCH more power. One thing also to consider is that you can use a large A/R due to the increased CFM of this type of setup.

I do have a 2.1L related question though. What parts do most people building 2.1L engines use for their valvetrains? I figure that stock valves (smaller diameter is lighter), aftermarket springs (single will suffice?), titanium retainers, and evo roller rockers (lighter, less polar inertia).

What about lifters? Do 2.1L engines that rev to their full potential use solid lifters? If so who sells them? Also, what cams can you use that are set up for a high reving, high performance application. I imagine the high ramp rate / high lift cams that are used on 2.0 and 2.4 engines will not be preferable at these high engine speeds, even with the proposed valvetrain.

Do any companies have a 2.1L 10,000rpm grind yet? I'm very interested in one, even if I have to idle at 3000rpm.

I also have a transmission that will shift at 10,000rpm already: Mazda RX7 Model R ;-). I've also recently found a 8 ½ lbs twin plate clutch/flywheel for 6bolt wideblocks from www.10000rpm.com that should work if I grow tired for my current 240mm single plate/Fidanza setup.

 

[Stapl3]

Show me one STREET CAR, not a weekend or some bullshit ass street driven race car that revs that high makes power and is usable.

You're forgetting about hondas.

 

[donmagicjuan]

Why do people think they need to rev the ever living piss outta motors?

Because horsepower is a linear function of torque vs. RPM. If you can generate the same torque at a higher RPM, you will make more power. This is the principle on which crotch rockets and race engines rely.
It allows for more power with less weight. After all, isn't that one of the reasons you have a turbocharged 4-cylinder, too?

The reason it would be silly to run an EvoIII at 10k is because it would be reasonable to assume that if you already made the modifications to the lower end, you also took care of the volumetric efficiency issues to ensure you would be making a decent amount of torque up there. Hence, you would be requiring a lot of airflow from the turbo, and you would be turning an EvoIII into a hairdryer. Hell, an EvoIII wouldn't be very useful at high RPMs even with stock cams and everything else at any respectable boost level.

 

[andymoraitis]

Andy, your explanation does not make much sense.

It would be silly to use a small turbo in this case though.

There's no way an EVO III can put out enough CFM to keep a motor like a 2.1 happy over the FULL powerband. I'm not talking about going from 2.5K to 7.5K. but from 2.5K to 10K. As you said, it makes more sense to do this with a much larger turbo since the available CFM will be much higher. When considering the amount of air that a motor like this would demand based on the valvetrain requirements alone, the EVO wouldn't stand a chance.

You and I are pretty much saying the same thing. Yes, it would work, but would it really be practical on a turbo that small? Certainly not.

As far as your stroker related questions, I would contact the crew at SBR. They've built some 2.1's and would have a more intimate knowledge of what cams and valvetrain would work best on that application. You may want to drop Jon Nye or Craig Evans a line. While people have successfully built 2.1's we don't hear too much about them on these forums hence the lack of available information on cam grinds, ramp rates, etc.

 

[DJpHGotBanned]

The reason it would be silly to run an EvoIII at 10k, is because it would be reasonable to assume that if you already made the modifications to the lower end, you also took care of the volumetric efficiency issues to ensure you would be making a decent amount of torque up there.

And your quote is probably the most important quote of this whole thread. This will only work if all parts of the system are designed to take advantage of the high reving design. Long intake runners... Big no no... tiny turbine housing.. big no no...

There are other things that become important with increasing revs as well including oil control in the bottom end (windage trays, crank scrapers, dry sump even). Also, some ignition or standalone ECUs might not even support over 10,000rpm, also might be worth running a 4 channel coil on plug setup.

Yeah, you dont NEED lots of the things you could do, but in order to really take advantage of a 2.1L engine, you'll need to consider the entire system so that it all works towards one goal. GROSSLY UNUSABLE POWER .

 

[GVR4592]

In order to really take advantage of a 2.1 you would most likely be wasting a ton of money. It isn't all it's made out to be, the guys running the really fast Dsm's stick with the 2.0 for a reason. It's not because they're ignorant, or because they're afraid of the unknown. It's because it's a waste of time and money. Destroking an engine can have a lot of benefits, but in our application I don't see any of them being noticeable with the 2.1.

Here's the part that is going to start the arguments. Contrary to what the vendors are saying you aren't going to rev this engine any higher than you can rev a 2.0. Why? Because we are still stuck with our shitty valvetrain design that won't allow it. Solid lifters would help, but how many of you are going to spend the time and money to buy and properly setup the solid lifters? How many of you are going to get custom cams made to take advantage of the longer dwell at TDC and the big loss in cylinder pressure during the closing of the intake valve? How many of you are going to get a custom intake manifold made with SMALLER runners to keep velocity up so you aren't restricting the engine? Same with the exhaust manifold and the ports in the cylinder head, velocity is the key. It has the potential to make more power at higher rpms, but it isn't going to rev any higher than 2.0, and it's sure isn't going to make any more power without the supporting mods.

Most of you guys don't realize that an engine isn't just a bunch of parts you bolt together. Everything has to match or it will be a disaster. If you aren't going to use the right engine components and supporting modifcations, you are wasting your money. Sure you could use a Magnus intake manifold, a Polk head, and a DNP tubular manifold. They're all great products, but are they matched to the engine? Probably not.

You'll get a 2-3% increase in VE at higher rpms, .14 liters of displacement, more dwell at TDC, a lighter piston, etc, etc. But how much of that are you going to notice? The changes are so minimal that you probably wouldn't notice.

The 2.1 has been availabe for at least 4 years from 2 vendors, if it was that much better, a lot more people would have one. I've only seen race results from 1, and it is in an Evo with a stock turbo.

If you want something that will be noticeable and probably well worth the money, look at the new Eagle 94mm crank, and the Magnus 93mm crank. Put either of these in a 2.4 block with Pauter/Oliver/Groden 156mm rods and some custom pistons, and you would have a 2.2/2.3 with a 1.66 or better rod ratio. It could reliably rev as high as the 2.0's do, but it would have .2-.3 liters more displacement. I believe AMS has built something similar for a few of their 1000AWHP customers. I've been bugging Eagle to make this crank for years and now that they've finally done it I have to build a new engine around it. Of course I'm going to get custom cams, intake manifold, exhaust manifold, cylinder head, etc. Otherwise it's just a waste of money.

Show me one STREET CAR, not a weekend or some bullshit ass street driven race car that revs that high makes power and is usable.

Evil_Eagle: Daily driven as of last season, not sure about this season, 650+whp, 9500 rpm's. If/when he gets some valvetrain upgrades, I'm sure he'll be revving higher.

 

[JOEY A]

You're contradicting yourself. In the post above you mention that you'd want a larger turbo if you were going to run high RPM, but you were thinking of doing this with an EVO III and a 2.1? Doesn't make much sense to me. That EVO would be clawing for breath well before 10,000 RPM and the motor would be outflowing it beyond belief.

Also, bumping compression up from 7.8:1 to 9:1 doesn't do much, if anything for off boost response. Read posts 7 and 9 from this thread:

http://www.dsmtuners.com/forums/showthread.php?t=224002

Displacement is what makes the big difference.

Yeah I know! The whole reason I have 9:1 is for off throttle boost response, and who the hell said I was going to rev to 10k? WTF?

 

[JOEY A]

I Never Said Or Would Run A Evoiii Past 7,000 Were The Hell Are You Guys Getting That From!!!!!!!!!!!!!!

 

[JOEY A]

Yeah I wanted a 2.1 just for spool!! not to rev to ever living hell on a 16G


Im also going to a larger turbo setup this year.

 

[fourreGsixty3]

Yeah I know! The whole reason I have 9:1 is for off throttle boost response, and who the hell said I was going to rev to 10k? WTF?

Firstly post one post not 3 within 5 minutes in the same thread.
Secondly, try being more curtious to our wisemen, and moderators, they give us valuable info.
Thirdly you only mentioned that you wanted a 2.1l with an Evo 3, the previous postes before were talking about going 10k rpms on the 2.1l, so your post could have been interperated many ways, also the off boost power that a 9:1 ratio will give you over a 8.5:1 is negligable, you wont even notice it with such a small turbo, with a stroker out motor. Also a lower CR will allow for more boost to be used, and that is noticable. Aslo with any stroker you will want to go with a larger turbo because it can take more power, and spools much quicker. The E3s spool quickly on a 2.0 so whats the point of spending an a$$ load of cash to have that baby turbo spool a couple hundred rpm quicker.

Dustin

 

[andymoraitis]

Yeah I know! The whole reason I have 9:1 is for off throttle boost response.

If you took a look at the thread I linked to, you'd see that the effect of compression ratio on off boost throttle response is minimal at best. As far as the argument that a 2.1 will help spool, that effect is also negligible. Finally, why would you build a 2.1 if you weren't going to rev that high? I just don't get it.

Anyway, it's likely in your best interests to calm down and not take this thread like it's some kind of personal attack.

 

[JOEY A]

Im sorry anymoritis, I came off more aggersive etc didnt really mean it to sound like that guys.

 

[andymoraitis]

Joey,

It's no big deal. This is the internet and things can get tangled very quickly.

No worries man. It's all good,

Andy

 

[V8KILR]

I just bought a Magnus 2.1 shortblock and it's in the process of being installed. I previously had a 2.4 but had issues with excessive vibration.
I can let you guys know how it is in a couple of weeks.
Some of my other mods are; GT35R, Magnus intake, tubular manifold, HKS 272's, 1000cc injectors, AEM ems, etc.