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Supernatural 3400 Roller cam? by La fiera
Started on: 04-18-2021 09:28 PM
Replies: 30 (451 views)
Last post by: La fiera on 05-15-2021 01:24 PM
La fiera
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Report this Post04-18-2021 09:28 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
Today I became the proud owner of a 3400 GM V6. I really purchased it for R&D porpuses. It'll be the test bed for mechanical roller cam profiles, stroker cranks and aluminum heads testing. Since I don't have sponsors or patrons to throw money for R&D it'll take me a while to develop it and like with the Supernatural 3.4L and 3.7L, I'll give you jst enough info on the build for you to make assumtions since no one is contributing. The 3.4L learing experice really gave me ideas where to exploit this 3400 improved block to make even more power efficiently.


PS. I hope Armaggedon doesn't come before I finish this one.
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Report this Post04-19-2021 12:30 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm eager to see what you can do with a Gen3 engine. The power potential should be a bit higher than the older ones.

Edit to add: Maybe try a crowd-funding campaign? I'd toss a few bucks into the pot.

[This message has been edited by Blacktree (edited 04-19-2021).]

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Will
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Report this Post04-19-2021 01:02 PM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:

Today I became the proud owner of a 3400 GM V6. I really purchased it for R&D purposes. It'll be the test bed for mechanical roller cam profiles, stroker cranks and aluminum heads testing. Since I don't have sponsors or patrons to throw money for R&D it'll take me a while to develop it and like with the Supernatural 3.4L and 3.7L, I'll give you just enough info on the build for you to make assumptions since no one is contributing. The 3.4L learning experience really gave me ideas where to exploit this 3400 improved block to make even more power efficiently.


PS. I hope Armaggedon doesn't come before I finish this one.


3.4's & 3400's have a 92mm bore.
LX9 3500's have 94mm bores, but still fit iron heads... if you don't want to go all the way to the aluminum heads, the LX9 block could build the biggest engine.
Also, from *I think* the LX9 on, GM bumped the rod journal size up to 2.250" to match the 4.3 v6. This means that the crank could be offset ground down to 2.100 or even 2.000 to stroke it. Joseph Upson did that on his 3900 build. However, GM might not have done this until the LZ4/LZ9 engines came out.
Some LX9's had forged cranks. I think all of them used the LS style 24x crank wheel.
All the LZ4/LZ9's use the 58x crank wheel.

Are you working with www.wot-tech.com on any parts?

What else you have under the bags?

[This message has been edited by Will (edited 04-19-2021).]

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La fiera
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Report this Post04-19-2021 06:47 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:

Are you working with www.wot-tech.com on any parts?

What else you have under the bags?



No, I'm doing all R&D and parts by myself. I have a local cam grinder which I've used for years. I also have a piston guy which does all my custom pistons. Recently I found a local operation that build CNC heads and intakes for NHRA teams and he is willing to help me design and make an improved aluminum head with the intake and exhaust pattern of the iron heads.
To be cost efficient I have to get 7 sets of heads done and that'll cost me $10,000. I wanted to make one set for me only so I can do some testing but it'll be too expensive for only two.
If I knew I could sell a few sets I'd get them so I can keep 2 sets for me and sell the rest.
Under the bags from left to right; The 3.4L I took out of my car, 383 stroker SBC for a customer and a 1.6L Ecoboost with forged internals for another customer.
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Report this Post04-20-2021 12:29 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Those custom heads sound interesting. If they could be made to flow as well as the Gen3 heads, you might be onto something.
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Report this Post04-20-2021 05:56 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
the LX9 has larger journals, I forget the exact measurements, but IIRC, they're the same as the 3800.

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La fiera
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Report this Post04-20-2021 10:09 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ericjon262:

the LX9 has larger journals, I forget the exact measurements, but IIRC, they're the same as the 3800.



Stroke is not what I'm after, dinamic displacement is, and I'm testing that with the Supernatural 3.7
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Report this Post04-21-2021 01:34 AM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:


Stroke is not what I'm after, dinamic displacement is, and I'm testing that with the Supernatural 3.7


journal diameter =/= stroke. the diameter is important to know because it helps select a connecting rod that will fit the rest of the engine/ build. I have set of pistons here in my garage for 3500, that are designed around a 3800 connecting rod, minimizing expenses for custom parts.

I can't remember for sure which rods I have, but they're either these:

https://www.summitracing.com/parts/esp-5967b3d

or these:

https://www.summitracing.com/parts/esp-6300v3d

now, it's important to understand, these rods are more narrow than stock 3500 rods, thus bearings will be smaller, and film load higher.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

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Report this Post04-21-2021 01:48 PM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had mentioned offset grinding for more stroke.

I don't think a 6.300 rod will fit in the V6/60... at least not with the 84mm stroke. It might just barely work with the 76mm stroke.
Narrower than V6/60 rods? That's pretty narrow, since the V6/60's are already narrower than SBC rods.
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Report this Post04-21-2021 08:32 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:

I had mentioned offset grinding for more stroke.

I don't think a 6.300 rod will fit in the V6/60... at least not with the 84mm stroke. It might just barely work with the 76mm stroke.
Narrower than V6/60 rods? That's pretty narrow, since the V6/60's are already narrower than SBC rods.


I have the rotating assambly already on the works. 6.125 rods weighting 525g each and the pistons as you imagine are very short and light. It'll be the same engine displacement but the geometry of the bottom end will be different so a cam revision will be required (I already have it). Also the intake manifold is being finished right now. The debate I have now is if to use the 3400 or the 3.4L block I have time to think.


On the left is the A beam 6.125' (525g) rod and the right is the H beam 5.400' (654g) of the current 3.7L in the car now. The longer rod has a smaller piston pin and smaller rod journal then stock. The longer rod will have more peak and top end power and the power delivery will be linear but the short rod will be explosive off the corners and low to mid acceleration. Of course that is matching both systems with their respective cam and intake needs.

PS. WOT or ZZP don't operate like me because they want to make money and I do it for fun.

[This message has been edited by La fiera (edited 04-21-2021).]

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Report this Post04-21-2021 09:41 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:

I had mentioned offset grinding for more stroke.

I don't think a 6.300 rod will fit in the V6/60... at least not with the 84mm stroke. It might just barely work with the 76mm stroke.
Narrower than V6/60 rods? That's pretty narrow, since the V6/60's are already narrower than SBC rods.


anything fits if you have a welder, and not much sense...

they end up with slightly more side clearance compared to stock, whether that would be a problem or not, I have no idea. I had them, I ran them.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

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Report this Post04-22-2021 05:13 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:


No, I'm doing all R&D and parts by myself. I have a local cam grinder which I've used for years. I also have a piston guy which does all my custom pistons. Recently I found a local operation that build CNC heads and intakes for NHRA teams and he is willing to help me design and make an improved aluminum head with the intake and exhaust pattern of the iron heads.
To be cost efficient I have to get 7 sets of heads done and that'll cost me $10,000. I wanted to make one set for me only so I can do some testing but it'll be too expensive for only two.
If I knew I could sell a few sets I'd get them so I can keep 2 sets for me and sell the rest.
Under the bags from left to right; The 3.4L I took out of my car, 383 stroker SBC for a customer and a 1.6L Ecoboost with forged internals for another customer.


What do you call the cam you made for me?
Practice?

LOL!
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Report this Post04-22-2021 11:07 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by lou_dias:


What do you call the cam you made for me?
Practice?

LOL!


Nope! That was methodically made just for you. It is basically a roller version of the cam in my 304WHP 3.4L but tailored for the short track you race on. Explosive low to mid torque and lots of mid to top end power. It was made specifically for you and power delivery is instantaneos, no lag. You have a unicorn!
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Report this Post04-23-2021 08:00 AM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:


Nope! That was methodically made just for you. It is basically a roller version of the cam in my 304WHP 3.4L but tailored for the short track you race on. Explosive low to mid torque and lots of mid to top end power. It was made specifically for you and power delivery is instantaneos, no lag. You have a unicorn!


Now I just need to get the engine builder off his ass...
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Report this Post04-24-2021 08:20 PM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ericjon262:


anything fits if you have a welder, and not much sense...

they end up with slightly more side clearance compared to stock, whether that would be a problem or not, I have no idea. I had them, I ran them.



I just meant that if you're not sure, I'm betting it's the one that fits rather than the one that doesn't...
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Report this Post04-27-2021 07:47 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:

https://i.ibb.co/SRJJsSJ/IMG-9482.jpg
On the left is the A beam 6.125' (525g) rod and the right is the H beam 5.400' (654g) of the current 3.7L in the car now. The longer rod has a smaller piston pin and smaller rod journal then stock. The longer rod will have more peak and top end power and the power delivery will be linear but the short rod will be explosive off the corners and low to mid acceleration. Of course that is matching both systems with their respective cam and intake needs.

PS. WOT or ZZP don't operate like me because they want to make money and I do it for fun.



Every argument for short rods I've ever read has related to the vacuum signal to the carb, and that the higher piston speeds result in stronger vacuum signal to a carb. I'm not sure how or if that would relate to EFI.
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Report this Post04-27-2021 09:38 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
This is just a guess, but maybe the stronger signal could also amplify the Helmholtz resonance effect in an EFI manifold.
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Report this Post04-28-2021 08:01 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:


Every argument for short rods I've ever read has related to the vacuum signal to the carb, and that the higher piston speeds result in stronger vacuum signal to a carb. I'm not sure how or if that would relate to EFI.


It's the same wether is carbed or EFI. I'm overlooking a bunch of variables but think about this simple example;
Engine A has the piston 1/4 (.25) inch down the bore at 45 degrees of crank rotation and Engine B has the piston 1/2 (.50) inch down the bore at the same 45 degrees of crank rotation. If more air charge equals more power; Which one of these two engines will make more power SOONER if power is dependent on how much inlet charge is ingested?
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Report this Post04-29-2021 09:31 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:


It's the same wether is carbed or EFI. I'm overlooking a bunch of variables but think about this simple example;
Engine A has the piston 1/4 (.25) inch down the bore at 45 degrees of crank rotation and Engine B has the piston 1/2 (.50) inch down the bore at the same 45 degrees of crank rotation. If more air charge equals more power; Which one of these two engines will make more power SOONER if power is dependent on how much inlet charge is ingested?


At the expense of reduced piston velocity later in the stroke when getting that last little bit of charge into the cylinder is critical for making maximum torque. Either way, a 3400 will pull 34 ci of displacement throughout the stroke. Flow through a pipe is proportional to the square *root* of pressure difference, so going to a higher pressure difference for a shorter time gets less mass through the pipe than a lower pressure difference for a longer time. Pull the high pressure difference early in the stroke doesn't benefit as much as a higher pressure difference later in the stroke. Pressure difference is related to the size of the port, so smaller ports develop greater pressure difference at a given demand from the piston, while larger ones maintain a lower pressure difference.
So if the ports are "big" relative to the cylinder, then the high piston speed early gets the charge in sooner, which ties into the vacuum signal to the carb argument. If the ports are "small" relative to the cylinder, then maintaining a lower pressure difference longer in the stroke gets more charge into the cylinder.

"Big" and "small" are relative to both displacement and RPM. I'm not convinced that iron head ports can be "big" relative to cylinders in a 3.7 liter engine at 9000 RPM...

[This message has been edited by Will (edited 04-29-2021).]

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Report this Post04-29-2021 11:30 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:
Either way, a 3400 will pull 34 ci of displacement throughout the stroke.


Technically you are correct but If that was a concrete true statement that would mean ALL 3400 will have the same power and that's not the case.
That's why I started the example saying: "I'm overlooking a bunch of variables".
If a variable can alter the pull of a 3400 stroke from 34 to 40ci, that's a variable I will absolutelly exploit and that is exactly what my Supernatural approach is. What does a turbocharger do? Increases pressure sacrificing velocity according to physics, but the net result is an increase on power and temperature. According to the "conservation of energy" law A1 V1=A2 V2 (there are other laws I exploit) I can accomplish the same result without a turbocharger by "FLIPING" the formula thus increasing velocity, dropping pressure and temperatue. It's just simple physics but going against the trend. And then add to that camshaft timing, exhaust pulse strenght and velocity, etc. It's way more complex than just installing a simple turbocharger and calling yourself and engine builder/designer. It takes wisdom which is experience learned over time, not intelligence which it is learned with books without experience.
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Report this Post04-30-2021 01:58 AM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
"engine masters" on motortrend actually tested rod length changes on an engine, they did this by building 2 engines as close to identical as possible, with the exception being the rods, pistons, and tune. the two engines made the same peak torque and power(within testing accuracy). That being said, both engine's connecting rods were within a "normal" range. The rod ratios were 1.8 and 1.63 for the two engines. The curves overlaid showed that the long rod combination made slightly more bottom end, and the short rod made slightly more top end. they came to conclusions that the differences in power came from differences in piston weights, or from ring control, the shorter rod having better ring control and more weight, the longer, worse ring control, but less weight. FWIW, the test engines were 478 cubic inch big block chevy engines

if one were to take the rod ratio outside of that drastically, there may be a more significant change.

My personal opinion is that the piston design is more important than rod length, a light piston, that doesn't rock, with good ring lands is more worthwhile than longer or shorter rods, but that's just my opinion.

------------------
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

cognita semper

[This message has been edited by ericjon262 (edited 04-30-2021).]

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Report this Post04-30-2021 11:23 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:

Technically you are correct but If that was a concrete true statement that would mean ALL 3400 will have the same power and that's not the case.
That's why I started the example saying: "I'm overlooking a bunch of variables".
If a variable can alter the pull of a 3400 stroke from 34 to 40ci, that's a variable I will absolutelly exploit and that is exactly what my Supernatural approach is. What does a turbocharger do? Increases pressure sacrificing velocity according to physics, but the net result is an increase on power and temperature. According to the "conservation of energy" law A1 V1=A2 V2 (there are other laws I exploit) I can accomplish the same result without a turbocharger by "FLIPING" the formula thus increasing velocity, dropping pressure and temperatue. It's just simple physics but going against the trend. And then add to that camshaft timing, exhaust pulse strenght and velocity, etc. It's way more complex than just installing a simple turbocharger and calling yourself and engine builder/designer. It takes wisdom which is experience learned over time, not intelligence which it is learned with books without experience.


That's why I wrote "displacement" instead of "charge". A 204 cid V6 is always going to displace 34ci per stroke. The short rod assembly "front loads" the volume rate so it pulls harder earlier in the stroke. The long rod assembly doesn't pull as hard as early, but maintains that pull later in the stroke. We're not talking huge differences here either. If you do the math and plot piston position vs. crank rotation on a graph, it's hard to tell the difference across different rod ratios unless comparing extremes like a 1.4:1 to a 2.0:1.

Darrin Morgan of Reher Morrison has said that rod length does not affect engine power. However, that's within the context of Pro-Stock engines with extreme RPM and YOOOOOOOOGE port flow. Builders of more normal engines find that while you can't get more power out of a set of cylinder heads with long rods vs. short rods, you can pick the wrong cam for the combo and lose power. All this leads me to my assessment that if you have "big" ports, pull hard early with a short rod combo. If you have "smaller" ports pull more gently, but for more of the stroke with a longer rod combo. "Big" or "Small" is relative to demand. Demand is a function of displacement and RPM.

That's the airflow side of it... Mechanically, within a given block deck, the long rod combo will have a lower recip mass and be more mechanically efficient, with lower frictional loss from major thrust side loading. Again, these are not big differences.
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Report this Post04-30-2021 11:26 AM Click Here to See the Profile for WillClick Here to Email WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post

Will

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quote
Originally posted by ericjon262:

"engine masters" on motortrend actually tested rod length changes on an engine, they did this by building 2 engines as close to identical as possible, with the exception being the rods, pistons, and tune. the two engines made the same peak torque and power(within testing accuracy). That being said, both engine's connecting rods were within a "normal" range. The rod ratios were 1.8 and 1.63 for the two engines. The curves overlaid showed that the long rod combination made slightly more bottom end, and the short rod made slightly more top end. they came to conclusions that the differences in power came from differences in piston weights, or from ring control, the shorter rod having better ring control and more weight, the longer, worse ring control, but less weight. FWIW, the test engines were 478 cubic inch big block chevy engines

if one were to take the rod ratio outside of that drastically, there may be a more significant change.

My personal opinion is that the piston design is more important than rod length, a light piston, that doesn't rock, with good ring lands is more worthwhile than longer or shorter rods, but that's just my opinion.


That's basically Reher-Morrison's POV... there are hundreds of factors that are more important than rod length and a builder should never alter a combo that already performs in order to pursue rod length.
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Report this Post05-03-2021 11:27 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:


That's why I wrote "displacement" instead of "charge". A 204 cid V6 is always going to displace 34ci per stroke. The short rod assembly "front loads" the volume rate so it pulls harder earlier in the stroke. The long rod assembly doesn't pull as hard as early, but maintains that pull later in the stroke. We're not talking huge differences here either. If you do the math and plot piston position vs. crank rotation on a graph, it's hard to tell the difference across different rod ratios unless comparing extremes like a 1.4:1 to a 2.0:1.

Darrin Morgan of Reher Morrison has said that rod length does not affect engine power. However, that's within the context of Pro-Stock engines with extreme RPM and YOOOOOOOOGE port flow. Builders of more normal engines find that while you can't get more power out of a set of cylinder heads with long rods vs. short rods, you can pick the wrong cam for the combo and lose power. All this leads me to my assessment that if you have "big" ports, pull hard early with a short rod combo. If you have "smaller" ports pull more gently, but for more of the stroke with a longer rod combo. "Big" or "Small" is relative to demand. Demand is a function of displacement and RPM.

That's the airflow side of it... Mechanically, within a given block deck, the long rod combo will have a lower recip mass and be more mechanically efficient, with lower frictional loss from major thrust side loading. Again, these are not big differences.


Reher Morrison builds 2000/4000hp nitrous with YOOOOOOOGE heavy valves to complement the YOOOOOOOOOGE cylinder bore and stroke with super heavy pistons, rods and cranks even though they use aluminum rods an super light pistons. I can guarantee you that their lightest parts are heavier than the parts of any 60 degree V6. Even Engine Masters used big displacement engines for their tests which are super heavy compared to parts in our engines. So, bottom line is the tests are obsolete, inconclusive and non compliant and do not apply to tiny valves, bores and strokes like our engines. Thats why every upgrade those big cubes heavy engines get are almost unoticeble. But for a small engine like ours those small gains are huge and can be seen in the results.

Lets test my theory.

https://youtu.be/hdcd0aySpFk

Big cubes and awesome power right? Lbs/ft per cubes will tell you how efficient the engine is making power according to Mr. David Vizard.
So, 890lbs.ft (at the crank) / 632 C.I.= 1.41 pounds per cube! That's Engine Master territory, awesome!!

Supernatural 3.4L on pump gas (to have a fair comparison) netted 300WHP. I'm not going to even attemt to use 15% drivetrain loss just to make a point, I'll keep it at the 300WHP mark.
300lbs/ft (at the wheels) / 207C.I.= 1.45 pounds per cube.

Now, if according to Mr. David Vizard, Which one of these two is more efficien? If Morrison's engine is Engine Masters territory where would my garage built stock short block with head work, "full stack intake" (like Will calls it) and flat tappet cam falls into?

Moral of the story is, don't believe what the "extperts" tell you. They are "experts" on their own right. They just want to make money.


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La fiera
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Report this Post05-04-2021 10:38 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ericjon262:

the LX9 has larger journals, I forget the exact measurements, but IIRC, they're the same as the 3800.



Larger journals may seem stronger but they are heavier and produce more friction and heat due to the higher velocity delta between the bigger rod journal and bigger crank journal. I believe 2.125?? The 3.4L is 2.00".

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Report this Post05-04-2021 10:48 PM Click Here to See the Profile for pmbrunelleClick Here to Email pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by La fiera:
more friction and heat due to the higher velocity delta between the bigger rod journal and bigger crank journal. I believe 2.125?? The 3.4L is 2.00".


If you are concerned about this, shouldn't you be running a thinner oil than the viscous oil (20W-50?) you usually run?
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Report this Post05-05-2021 06:40 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:


If you are concerned about this, shouldn't you be running a thinner oil than the viscous oil (20W-50?) you usually run?


You have a point Patrick. I usually run 10W-40, but If I'm going to the track I'll use 15W-50 on the Fiero and in the Abarth.
The journal of this new piston and rod combo is 1.88", so it is smaller than the 2.00" 3.4L and even smaller than the 3400 roller block crank.
The way I see it is that it is more efficient to stir a small/light spoon in maple syrup than a big heavy spoon in water. The maple syrup would do a much better job deadening the small spoon to glass contact than the big spoon to glass contact in water. Also, I can swing a small hammer much faster and for longer periods than a heavier one without getting my forearm to cramp.

Then there is the argue that bigger journals are stronger, technically yes. But since my engine is not turbocharged I don't worry much about crank or piston strength.
Yes, NASCAR engines use 1.88" journals only for one race but they are making 850-900hp constantly roundy round at 9000rpms and I'll only be making 350hp at top end and revving it from 2500 to 9000rpm, so I should be ok for the long run.
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Report this Post05-14-2021 05:40 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:


Larger journals may seem stronger but they are heavier and produce more friction and heat due to the higher velocity delta between the bigger rod journal and bigger crank journal. I believe 2.125?? The 3.4L is 2.00".


I'm not 100% on the size, and it's fairly low on my current priority list to measure them, when I get to SC I can go to my storage unit and take a look. As with almost anything it's a trade off, there's no doubt the larger journal is stronger, if nothing else, the overlap between the crank and rod journals will increase the stiffness of the crank, which could lead to performance gains as well. the journals could also potentially be gun drilled to remove weight, with minimal strength loss.

As far as the engine masters testing is concerned, I think it's still relevant, to the discussion of rod length. testing was performed to test both transient and steady state output differences, as well as running the engine at different rates of speed change (300RPM/sec and 600RPM/sec IIRC) if you're worried about the engine's efficiency, about 40% of the friction is piston rings, fewer, thinner rings, with lower tension will make a drastic improvement in efficiency, as long as they seal well. the next engine I build will probably get gapless top rings

the ft-lbs/cube example you made above isn't really valid unless both engines were run on the same dyno (or at least the same make and model)under similar atmospheric conditions. differences in data acquisition, instrumentation, and correction factors can play a huge role in indicated power.

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Report this Post05-14-2021 07:54 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ericjon262:

the ft-lbs/cube example you made above isn't really valid unless both engines were run on the same dyno (or at least the same make and model)under similar atmospheric conditions. differences in data acquisition, instrumentation, and correction factors can play a huge role in indicated power.



I didn't make that rule, the "experts" did and I'm not one of them. I just build things for my satisfaction not business. I can guarantee you Mr. Morrisson had everything in that dyno room at the best "weather".; he needs business! I don't!
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Report this Post05-15-2021 12:05 PM Click Here to See the Profile for ericjon262Send a Private Message to ericjon262Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by La fiera:


I didn't make that rule, the "experts" did and I'm not one of them. I just build things for my satisfaction not business. I can guarantee you Mr. Morrisson had everything in that dyno room at the best "weather".; he needs business! I don't!


that's not a "rule" made by "experts" that's the scientific method, remove testing variables to produce repeatable, comparable results. if the dyno he used calculates torque and horsepower by a different method, different results may be found. if the engine was run on the dyno in a very dry climate, say Arizona or California, and then in Florida, or Georgia, it will also likely produce different results. Stack these testing variances and the difference in outcome can be substantial. "correction factor" differences can also make for very large differences in output as well, even on the same engine, on the same dyno, back to back runs.

------------------
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Report this Post05-15-2021 01:24 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ericjon262:


that's not a "rule" made by "experts" that's the scientific method, remove testing variables to produce repeatable, comparable results. if the dyno he used calculates torque and horsepower by a different method, different results may be found. if the engine was run on the dyno in a very dry climate, say Arizona or California, and then in Florida, or Georgia, it will also likely produce different results. Stack these testing variances and the difference in outcome can be substantial. "correction factor" differences can also make for very large differences in output as well, even on the same engine, on the same dyno, back to back runs.



I'm well aware how dynos vary one from another even if they are of the same brand. That's why I've been using the same Mustang dyno at the same location over the years.There's plenty of Dynojets around here but I want to keep things accurate so I can tests parts and really see if they work or not.
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