Wow, I didn't get to read through the whole thing yet, but great job!! Nice work!

Damn, good work, i am in teh works for a build myself and i am always questioning my self about going 2.4 or not.

turbotalon1g said:

Damn, good work, i am in teh works for a build myself and i am always questioning my self about going 2.4 or not.

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I dont post many random posts, but that document is aweseome. Great read.

~Ryan

You should submit this to the tech articles--I haven't gotten through it yet, but I look forward to it. Great job once again!

Good Read. as an engineer and engine builder, i am very impressed in the depth of the paper.

I'm not done reading it yet, but I did save it to my laptop for future reference. VERY well written/researched, and very informative. This needs to be stickied somewhere.

Just finished reading it all and it took awhile and wow. Very informative, some of it was rather hard to keep up with but i did find it accurate information. It basically concluded to what we all know but I would deem it still interesting. The part about the beliefs towards balance shaft removal being a negative was interesting as well which in turn did make sense. Ive always summed up that well built 2.3 stroker should be safe revving to 8k, any more rpm than that could get ugly... Appears also the 2.1 destroker would be the most ideal stroke for us.
Anyways thanks for the good write up!
This should be stickied in the stroker section !

Commenters all,
Thanks for the good words. Seven tuners made positive comments and the document has been hit 109 times on my site since yesterdays posting, 55 times from this site, 30 times from sddsm.org where someone must have copied the link and the rest returning visitors who must not have remembered the whole paper on the first read.

Ludachris has volunteered to create a tech article and reference the paper so the sticky part is taken care of.


Black_Bullet,
Right you are, my rev limiter is set for 8K and I kept the balance shafts (with new bearings).

TunaTalon said:

Commenters all,
Thanks for the good words. Seven tuners made positive comments and the document has been hit 109 times on my site since yesterdays posting, 55 times from this site, 30 times from sddsm.org where someone must have copied the link and the rest returning visitors who must not have remembered the whole paper on the first read.

Ludachris has volunteered to create a tech article and reference the paper so the sticky part is taken care of.


Black_Bullet,
Right you are, my rev limiter is set for 8K and I kept the balance shafts (with new bearings).

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Wish I had the money to do a 2.3, ive always wanted one since ive had awd!
2.3 revving to 8k with the appropriate cams for the application plus a gt30r and 25+ psi sounds wicked...

I didnt notice any information reguarding the 2.4 4g64 strokers....
Ive heard those are better than the 2.3's for street type applications were as the rod angles arent as harsh
yet still getting even more displacement in the mix.

Nice write up. I myself have never wanted to stroke my engine, but a 2.1 is tempting now.

Black_Bullet said:

2.3 revving to 8k with the appropriate cams for the application plus a gt30r and 25+ psi sounds wicked...

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It is. I've been in that exact car. BB GT30R with 30PSI on pump+meth injection. It is AMAZING to say the least.

BoostFrenzy said:

Nice write up. I myself have never wanted to stroke my engine, but a 2.1 is tempting now.



It is. I've been in that exact car. BB GT30R with 30PSI on pump+meth injection. It is AMAZING to say the least.

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Damn now im jealous.

Black_Bullet said:

I didnt notice any information reguarding the 2.4 4g64 strokers....
Ive heard those are better than the 2.3's for street type applications were as the rod angles arent as harsh
yet still getting even more displacement in the mix.

Click to expand...

Bored 40 over my "2.3L" comes in at 2.35L, close enough for me to decide to keep the project simple.

The stock 2.4L has the same 150mm rods and 100mm stroke as my 2.3L stroker so the rod ratio is the same and all inertial loads are the same. All of the charts in the document for the 2.3L would be the same for the 2.4L. Using a stroker piston with the pin moved up and a longer rod on a 2.4L block could give a better rod ratio.

If you keep the balance shafts and use full weight pistons and rods the 2.4L's balance shafts would compensate better. But with my lighter eagle rods and wiseco pistons the harmonic imbalance for the 100mm stroke was about the same as OE parts with the 88mm stroke. With the Prothane mounts I really don't need any more vibration.

TunaTalon said:

Bored 40 over my "2.3L" comes in at 2.35L, close enough for me to decide to keep the project simple.

The stock 2.4L has the same 150mm rods and 100mm stroke as my 2.3L stroker so the rod ratio is the same and all inertial loads are the same. All of the charts in the document for the 2.3L would be the same for the 2.4L. Using a stroker piston with the pin moved up and a longer rod on a 2.4L block could give a better rod ratio.

If you keep the balance shafts and use full weight pistons and rods the 2.4L's balance shafts would compensate better. But with my lighter eagle rods and wiseco pistons the harmonic imbalance for the 100mm stroke was about the same as OE parts with the 88mm stroke. With the Prothane mounts I really don't need any more vibration.

Click to expand...

Oh ok thanks ... Id probably do .40 over as well if i did a stroker to get full displacement as ive been told .20 over barely makes it a 2.3 if you round it off....

after reading it again, i have issue with a a few things.

this data is very clean and ideal =theoretical model. (real and theoretical are very different, take into account engine temp., clearances, ring gap, the type of tune and it all changes yet again.)

For most of us, we have our engines internally balanced, and although i'm anal about vibrations of any sort, i don't see issue with taking out the balance shafts, and another point the timing belt takes out a lot of the vibrations from the crank.

and most important all this info is for n/a engines, add boost and everything you know and use for a n/a engine goes out the window.

sbengineering said:

after reading it again, i have issue with a a few things.

this data is very clean and ideal =theoretical model. (real and theoretical are very different, take into account engine temp., clearances, ring gap, the type of tune and it all changes yet again.)

For most of us, we have our engines internally balanced, and although i'm anal about vibrations of any sort, i don't see issue with taking out the balance shafts, and another point the timing belt takes out a lot of the vibrations from the crank.

and most important all this info is for n/a engines, add boost and everything you know and use for a n/a engine goes out the window.

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sbengineering,
Right you are about the theoretical basis of the white paper. It is strictly a mathematical analysis of piston dynamics of the 4G63 engine. Math is limited but not all bad.

The analysis of the effect of balance shafts assumes absolutely perfect balance of the rotating assembly to calculate the harmonic imbalance forces. Read it again, very carefully. Some old understandings I have held dear for 48 years are challenged.

Since my teen years I believed that a piston going up “balanced” another piston going down. Wrong. The two pistons may be the same weight but if their velocities are different they are not balanced.

I acknowledge that the math doesn’t agree with your understanding. Or mine prior to the research. Either our understanding was wrong or the math is wrong.

But then I’m biased, I’ve spent most of my life looking for the “better way” and not trusting “that’s the way it is”.

i agree math is right on, just never that simple in the real world. However, if anything, it agrees with my gut to sticking with the stock stroke.

But, again very well written and the time you have spent working on this is very appreciated by all of us.

On a side note, what mathematical software did you use to help you out.

sbengineering said:

i agree math is right on, just never that simple in the real world. However, if anything, it agrees with my gut to sticking with the stock stroke.

But, again very well written and the time you have spent working on this is very appreciated by all of us.

On a side note, what mathematical software did you use to help you out.

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Ah yes the gut feel is the only truth, math just shows us the reason. That's why the white paper has no recommendations. So far I have comments that the paper proves that the 2.1L is the best 4G63, Strokers are the way to go, and that the stock stroke is the best. All are true, for the different goals of the different people.

The time spent on the document was no more than fair payment for what I have learned from this forum and other sources while planning my Talon Project. If I were really ambitious I could have calculated the horsepower required to shake a 3200 pound car at the same frequency and amplitude as a 4G63 without balance shafts.

All charts were created from an Excel worksheet. All formulas used are listed in the white paper along with the reference source or my derivation. The worksheet is available for download from http://kidzuku.com\4G63PistonForces.zip.

Wow, great read.... I agree with your final three thoughts.

Hmmmm torque good.
Me stroke Talon.
Make tires happy. (or very unhappy depending)

Now I'm a lot less worried about building a stroker. I am curious what kind of mileage (both longevity and gas) ppl are getting out of their 2.3 for DD duty.

My only concern is with the balance shaft belt breaking, and causing all my hard work to go out the drain, specialy when i am trying a to build something reliable, and will live up to DD on the street.

01QuadDak said:

My only concern is with the balance shaft belt breaking, and causing all my hard work to go out the drain, specialy when i am trying a to build something reliable, and will live up to DD on the street.

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The balance shaft belt breaking is a real possibility especially on a high mileage engine that is rev’ed higher than the original design. The StrokeOrNot paper avoids making a recommendation on removing the Balance Shafts or leaving them in because tuner DSM’s only have to make the owner happy, not the great unwashed masses.

I do recommend strongly against leaving unmaintained balance shafts in place in high mileage engines. After 183,000 miles bathed in Mobil One oil my 4G63’s main and rod bearings showed no signs of wear. However, the balance shaft bearings were obviously worn down. If I had just continued replacing the balance shaft belt every 60K a worn down bearing would have seized and wreaked havoc on my Talon.

In fewer words: Take care of the balance shafts or take them out.

Very well done. I thought I was back in my calculus classes.

Do you know anything about the issue of having the oil rings located in the top of the rod pin for the 2.3Lstroker pistons vs the 2.4L pistons the Oil rings are located above the rod pin location on the pistons because of the block being 5.9-6mm higher than the 2.0L block...????(these are aftermarket pistons im talking about) I heard that oil consumption on a stroker is minimal but still a higher % than the stock 2.0L? Thats the main reason why I went with the G4CS block vs the 4g63 stroker

Idk, but I have heard of some people removing the oilers altogether. I am not sure if this is "right" but I know it has been done, and I have even seen speed shops sell complete stroker engines this way.

In short I was talking about the Oil rings go through the piston on a stroker engine because they are using a longer stroke crank so the rod pin hole is farther up the piston to allow for an ideal comp ratio. As for using the 2.4L blocks being that they are 6mm higher than the 4g63 their pistons oil rings are located above the rod pin hole. Which to me would seem to be better for a street car considering you would burn more oil with a stroker.. Now this is very marginal but I'm saying You would burn less with a stock 2.0L or a 2.4L block.. Thats what my question was about...