Asm Update!!!!!! [Archive] - Cherokee SRT8 Forum

: Asm Update!!!!!!


FastSRT8GC
04-06-2007, 06:40 AM
Talked to Jim at ASM yesterday. He said that they will be tuning the Jeep and then the Kit should be done. All pieces are being machined or chromed as we type. He sent me some photos of the PROTOTYPE. This is not a finished kit so dont go calling its imperfections out yet, we will do that to the finished product.
Here is his quote from the email and the photos ENJOY!!

"Here are some photos of progress on the project. Please remember this is not
the final product, there is a coolant recovery tank that fits under the duct
near the fender, which is not shown, and the after cooler is not yet
polished. Programming of the Plug & Play and testing is the next step. "

http://www.cherokeesrt8.com/gallery/watermark.php?file=287&size=1

http://www.cherokeesrt8.com/gallery/watermark.php?file=288&size=1

http://www.cherokeesrt8.com/gallery/watermark.php?file=289&size=1


http://www.cherokeesrt8.com/gallery/watermark.php?file=290&size=1

ndm
04-06-2007, 06:46 AM
UH OH!!! I can smell the excitement!!!!

I cant afford to do this but I know people that can are starting to shake from excitement....

BuilderBill
04-06-2007, 06:49 AM
Talked to Jim at ASM yesterday. He said that they will be tuning the Jeep and then the Kit should be done. All pieces are being machined or chromed as we type. He sent me some photos of the PROTOTYPE. This is not a finished kit so dont go calling its imperfections out yet, we will do that to the finished product.
Here is his quote from the email and the photos ENJOY!!
Fast,
I am enjoying!!!
Hope to take some photos next Thursday when I am out there.
Thanks again for the great update!
Bill

SilverSRT8
04-06-2007, 06:58 AM
Is it wrong that I get excited when I see big polished tubes under a hood???

SRT-8RAT
04-06-2007, 08:38 AM
Any word on the price?

Looks nice!

Blown-WK
04-06-2007, 09:08 AM
Sweet, glad to see some progress. Hope they get it up and running soon.

GotStroke?
04-06-2007, 09:28 AM
I can't help but get excited for you guys!

FFSP
04-06-2007, 10:22 AM
Looks great man. Can't wait to see the numbers that thing makes.:cool:

Any word on the price?



$7600.

BuilderBill
04-06-2007, 11:36 AM
Looks great man. Can't wait to see the numbers that thing makes.:cool:



$7600.
The base unit they are prototyping is 125 additional hp for the $ 7,600. I know, on eBay you can buy something better (LOL) for under
$ 2,000. As one who researched the hell out of this (and has a 50% down payment) I still feel for a low production unit that is not bad. Some may feel what my company charges for structural home repairs is a lot, but, as most things in life, as you grow older, you realize more and more,that you get what you pay for in quality and service.

Anyway, back to the numbers, I am having a well known Mopar engine builder build a stroker motor, made for the forced induction, so AZ is cranking up the boost which will crank a few more ponies than the 125 hp. Boy, this is fun!
Bill

Razorecko
04-06-2007, 12:17 PM
The base unit they are prototyping is 125 additional hp for the $ 7,600. I know, on eBay you can buy something better (LOL) for under
$ 2,000. As one who researched the hell out of this (and has a 50% down payment) I still feel for a low production unit that is not bad. Some may feel what my company charges for structural home repairs is a lot, but, as most things in life, as you grow older, you realize more and more,that you get what you pay for in quality and service.

Anyway, back to the numbers, I am having a well known Mopar engine builder build a stroker motor, made for the forced induction, so AZ is cranking up the boost which will crank a few more ponies than the 125 hp. Boy, this is fun!
Bill

I wonder if the stock motor would be able to handle a 125hp increase for a long time, as im sure many people would love to slap on a blower w/out having to open up the engine.

BuilderBill
04-06-2007, 12:25 PM
I wonder if the stock motor would be able to handle a 125hp increase for a long time, as im sure many people would love to slap on a blower w/out having to open up the engine.
Fast is betting that the motor will hold with the additional 125 hp from the supercharger and I tend to agree with him. I went with the entire combo as more of a down time savings since I would most likely wind up with this setup at some date.
Bill

FastSRT8GC
04-06-2007, 01:56 PM
ASM will not sell the kit if the bottom end could not handle the boost. I believe that the 4-6psi will be very reserved for the reliability aspect of it.

I unlike Bill plan on pushing the PSI up till i pop the bottom end. We need someone to test the limits of the pistons, rings etc. that would be me. Plus with the high flow of the DR heads I will need some more PSI anyway;)

Crank
04-06-2007, 01:56 PM
Well i know they say the rods are the weekest part of our engines. I blew two rods out a ford engine before so lets hope this doesnt happen.

BuilderBill
04-06-2007, 02:58 PM
Well i know they say the rods are the weekest part of our engines. I blew two rods out a ford engine before so lets hope this doesnt happen.
I think the weak link in our mighty Hemi's are the pistons. FAST will do the right thing and eventually (like about 60 days) :D push some boost into that engine, therefore letting us know the weak link for sure!
Bill

GotStroke?
04-06-2007, 04:16 PM
A little rod related info, though 4.6 based still holds true in our case.

From what I have seen as well, most rods fail in tension. The only ones I've seen fail in compression are from a hydraulic or mechanical bind. Sometimes it's hard to determine though, since the rod will likely whack the block, oil pan, and whatever else is close a couple hundred times before it stops moving.

First I'll address failures in Tension:

This is what the piston acceleration looks like in a stock 4.6 at 8000 RPMs


http://i142.photobucket.com/albums/r95/ATOMonkey/4.jpg



0 degrees is TDC 180 is BDC and 360 is back to TDC again. As you can see, just from spinning the engine the piston applies over 4,000 times the weight of the piston on the con rod as the piston approaches TDC and moves away from TDC.

Fortunately 3.55" short skirt pistons don't weigh very much so even though the piston exerts 4,000 times the force of gravity at 377 grams that works out to about 355 lbs of force hanging off your con rod. Now, to get max stress in the rod we just divide 355 by the min cross sectional area. Let's estimate .25 in^2 just to make a number. That would make 1420 psi of stress, which is nothing in terms ultimate tensile strength. Your forged steels can be as high as 130,000 psi easy. Cast iron is only good to about 50 ksi or so though. That's why cast rods are crap.

However, when you put 8,000 cycles per minute on your rods, you need to be more worred about high cycle fatigue strength. For 4340, you don't want to go over about 50 ksi. So, in our case it looks like we're ok from a fatigue stand point. In tension.

Now for compression!

Standard peak firing pressures in a 400 hp 4.6 can be well over 600 psi. This puts over 5,900 lbs of force on the con rod. This puts our rod stress at 23.7 ksi. Much higher, but still ok for HCF. In the event of detonation cylinder pressure will exceed 1000 psi easy. This gives us close to 1,000 lbs of force on the rod and over 39.5 ksi. This is starting to get pretty close to inducing rod failure.

The second thing we have to look at for compression in a rod is buckling.

http://i142.photobucket.com/albums/r95/ATOMonkey/buckling.jpg

Buckling force is given as
Where E is the modulus of elasticity, I is the moment of inertia, and L is the effective length of the rod. For our double pinned rod the center to center length is what we're interested in. The moment of inertia is calculated at a specific cross section, which makes it difficult to determine exactly what force will cause a con rod to buckle because the cross section is not constant along the length of the rod. However, you can get a good approximation at the center of the rod. The moment of inertia about the bending axis of the rod can be calculated piece wise as 1/12 b h^3. The modulus of elasticiy for steel is 29 msi so you can see that the load needed to buckle a rod will be quite high. Much higher than most anything a street engine will produce.

What does this all mean? The cast pistons are going to be the weak link in any OEM engine, just as long as the OEM rod bolts are up to par. Regardless, if you want it to live, forge everything /end story.

BuilderBill
04-06-2007, 06:13 PM
A little rod related info, though 4.6 based still holds true in our case.

From what I have seen as well, most rods fail in tension. The only ones I've seen fail in compression are from a hydraulic or mechanical bind. Sometimes it's hard to determine though, since the rod will likely whack the block, oil pan, and whatever else is close a couple hundred times before it stops moving.

First I'll address failures in Tension:

This is what the piston acceleration looks like in a stock 4.6 at 8000 RPMs


http://i142.photobucket.com/albums/r95/ATOMonkey/4.jpg



0 degrees is TDC 180 is BDC and 360 is back to TDC again. As you can see, just from spinning the engine the piston applies over 4,000 times the weight of the piston on the con rod as the piston approaches TDC and moves away from TDC.

Fortunately 3.55" short skirt pistons don't weigh very much so even though the piston exerts 4,000 times the force of gravity at 377 grams that works out to about 355 lbs of force hanging off your con rod. Now, to get max stress in the rod we just divide 355 by the min cross sectional area. Let's estimate .25 in^2 just to make a number. That would make 1420 psi of stress, which is nothing in terms ultimate tensile strength. Your forged steels can be as high as 130,000 psi easy. Cast iron is only good to about 50 ksi or so though. That's why cast rods are crap.

However, when you put 8,000 cycles per minute on your rods, you need to be more worred about high cycle fatigue strength. For 4340, you don't want to go over about 50 ksi. So, in our case it looks like we're ok from a fatigue stand point. In tension.

Now for compression!

Standard peak firing pressures in a 400 hp 4.6 can be well over 600 psi. This puts over 5,900 lbs of force on the con rod. This puts our rod stress at 23.7 ksi. Much higher, but still ok for HCF. In the event of detonation cylinder pressure will exceed 1000 psi easy. This gives us close to 1,000 lbs of force on the rod and over 39.5 ksi. This is starting to get pretty close to inducing rod failure.

The second thing we have to look at for compression in a rod is buckling.

http://i142.photobucket.com/albums/r95/ATOMonkey/buckling.jpg

Buckling force is given as
Where E is the modulus of elasticity, I is the moment of inertia, and L is the effective length of the rod. For our double pinned rod the center to center length is what we're interested in. The moment of inertia is calculated at a specific cross section, which makes it difficult to determine exactly what force will cause a con rod to buckle because the cross section is not constant along the length of the rod. However, you can get a good approximation at the center of the rod. The moment of inertia about the bending axis of the rod can be calculated piece wise as 1/12 b h^3. The modulus of elasticiy for steel is 29 msi so you can see that the load needed to buckle a rod will be quite high. Much higher than most anything a street engine will produce.

What does this all mean? The cast pistons are going to be the weak link in any OEM engine, just as long as the OEM rod bolts are up to par. Regardless, if you want it to live, forge everything /end story.
Damn, as a graduate Mechanical Engineer, I am going to have to open a great bottle of wine and really study this. Oh, what the hell, open the wine and just buy the best forged pieces available. Best to study this with coffee in the am.

Great info Stroker!
Bill

StageFright
04-06-2007, 09:47 PM
A little rod related info, though 4.6 based still holds true in our case.

From what I have seen as well, most rods fail in tension. The only ones I've seen fail in compression are from a hydraulic or mechanical bind. Sometimes it's hard to determine though, since the rod will likely whack the block, oil pan, and whatever else is close a couple hundred times before it stops moving.

First I'll address failures in Tension:

This is what the piston acceleration looks like in a stock 4.6 at 8000 RPMs


http://i142.photobucket.com/albums/r95/ATOMonkey/4.jpg



0 degrees is TDC 180 is BDC and 360 is back to TDC again. As you can see, just from spinning the engine the piston applies over 4,000 times the weight of the piston on the con rod as the piston approaches TDC and moves away from TDC.

Fortunately 3.55" short skirt pistons don't weigh very much so even though the piston exerts 4,000 times the force of gravity at 377 grams that works out to about 355 lbs of force hanging off your con rod. Now, to get max stress in the rod we just divide 355 by the min cross sectional area. Let's estimate .25 in^2 just to make a number. That would make 1420 psi of stress, which is nothing in terms ultimate tensile strength. Your forged steels can be as high as 130,000 psi easy. Cast iron is only good to about 50 ksi or so though. That's why cast rods are crap.

However, when you put 8,000 cycles per minute on your rods, you need to be more worred about high cycle fatigue strength. For 4340, you don't want to go over about 50 ksi. So, in our case it looks like we're ok from a fatigue stand point. In tension.

Now for compression!

Standard peak firing pressures in a 400 hp 4.6 can be well over 600 psi. This puts over 5,900 lbs of force on the con rod. This puts our rod stress at 23.7 ksi. Much higher, but still ok for HCF. In the event of detonation cylinder pressure will exceed 1000 psi easy. This gives us close to 1,000 lbs of force on the rod and over 39.5 ksi. This is starting to get pretty close to inducing rod failure.

The second thing we have to look at for compression in a rod is buckling.

http://i142.photobucket.com/albums/r95/ATOMonkey/buckling.jpg

Buckling force is given as
Where E is the modulus of elasticity, I is the moment of inertia, and L is the effective length of the rod. For our double pinned rod the center to center length is what we're interested in. The moment of inertia is calculated at a specific cross section, which makes it difficult to determine exactly what force will cause a con rod to buckle because the cross section is not constant along the length of the rod. However, you can get a good approximation at the center of the rod. The moment of inertia about the bending axis of the rod can be calculated piece wise as 1/12 b h^3. The modulus of elasticiy for steel is 29 msi so you can see that the load needed to buckle a rod will be quite high. Much higher than most anything a street engine will produce.

What does this all mean? The cast pistons are going to be the weak link in any OEM engine, just as long as the OEM rod bolts are up to par. Regardless, if you want it to live, forge everything /end story.

http://images.corvetteforum.com/images/smilies/Yawn.gif

GotStroke?
04-06-2007, 09:59 PM
http://images.corvetteforum.com/images/smilies/Yawn.gif

http://i12.tinypic.com/4bi57o4.jpg

nyjpny
04-07-2007, 08:41 AM
http://i12.tinypic.com/4bi57o4.jpg
lol that was what i was thinking