Piston Bowls

MarkBroviak

DMax Junkie
Vendor/Sponsor
May 25, 2008
2,134
464
83
Danville Indiana
Sorry but I will have to politely dissagree with all of you on this subject. By your thinking my 15.25:1 comp motor should be a laggy, smoky, cold weather hating machine and that couldn't be farther from the truth. There is soooooo much more that goes into besides the compression ratio.
 

LBZrcks

.........
Jun 2, 2007
5,297
12
38
38
SoCal
Other then Adam (malibu) is there anyone running these cast pistons in a DD and towing? If so what power level?
 

ripmf666

Active member
Sep 20, 2006
15,123
14
38
47
Wentzville Mo
Sorry but I will have to politely dissagree with all of you on this subject. By your thinking my 15.25:1 comp motor should be a laggy, smoky, cold weather hating machine and that couldn't be farther from the truth. There is soooooo much more that goes into besides the compression ratio.

X2
 

MarkBroviak

DMax Junkie
Vendor/Sponsor
May 25, 2008
2,134
464
83
Danville Indiana
Other then Adam (malibu) is there anyone running these cast pistons in a DD and towing? If so what power level?

The trucks that I have them in range from my DD 2wd lbz 535hp-800hp vgt single charger, 1040hp twin turbo lbzstreet truck,700-850Hp Billet S475-87 T4 Single LLy DD/ plow truck, 9 sec. 1105+Hp VGT twinned LLy drag truck that gets street drivin and has working a/c, 650hp stock/twin turbo LLy on stock fuel system, and I'm in the process of building a few sled pulling engines with these pistons also.
 

05smoker

I'm officially done!
Mar 30, 2007
2,379
0
36
Lebanon, OH
Sorry but I will have to politely dissagree with all of you on this subject. By your thinking my 15.25:1 comp motor should be a laggy, smoky, cold weather hating machine and that couldn't be farther from the truth. There is soooooo much more that goes into besides the compression ratio.

Thanks for chiming in Mark. People hear 15:1 and think it won't spool the charger or start under 70 degrees.

But I wouldn't go as low as my old puller was. :D
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
Im not saying its "uncivilized" or like a 12valve pulling truck............im just saying that, all things being equal (stock heads, stock cam, etc), lowering CR noticeably effects how snappy the truck feels around town.

Not saying it wont start in the cold either. Back in 2008 I put my ~16:1 'built' engine through a winter of below-zero temps without being plugged in and it started fine. But it was just noticeably lazier feeling around town (MPI twins with VVT) and didnt get the same fuel economy as a stock engine....and it smoked a little more in the cold.

In MY OWN OPINION...given the choice...from what I have experienced in driving stock CR stock motors, stock CR built motors, and low CR built motors.......my own personal preference is stock CR.

ben
 

MarkBroviak

DMax Junkie
Vendor/Sponsor
May 25, 2008
2,134
464
83
Danville Indiana
http://www.youtube.com/watch?v=p2oy3pS59CA&feature=youtu.be

Watch and tell me if you still think low compression is laggy for driving. Ben, yours was laggy because of your twins, I had the same issue when I install MPI base kit on my truck and it took me a year to get them figured out and get rid of that lag your referring to. With a lower compression motor(if you have the parts combination set up right) you will get more work out of the fuel charge and that is a fact. That is where you power comes from.
 

sweetdiesel

That's better
Aug 6, 2006
10,390
0
0
52
Thailand
I agree (not often) with Ben. LOL I have run both also. I did notice a differance also.

Jeff , I know your not into the tuning game. but changes can be made ( Ben as a tuner, beta tester ) should know this that adjustments to tliq, base tq will help spool timing adds or subratcts heat and then there is fuel press to stop hazing..... it can all be done!:)
 

MACKIN

Smell My Finger...
Aug 14, 2006
3,948
1
0
Connecticut
The trucks that I have them in range from my DD 2wd lbz 535hp-800hp vgt single charger, 1040hp twin turbo lbzstreet truck,700-850Hp Billet S475-87 T4 Single LLy DD/ plow truck, 9 sec. 1105+Hp VGT twinned LLy drag truck that gets street drivin and has working a/c, 650hp stock/twin turbo LLy on stock fuel system, and I'm in the process of building a few sled pulling engines with these pistons also.

WOW really? Well that's a testament to these pistons ! :thumb:
 

ecc_33

Junior Member
Aug 10, 2006
1,925
0
0
39
Amanda, Ohio
When i cc'd my pistons i was no higher than 14.5 to 1. My truck is no different then when it was the stock long block. The only thing that changed from the stock motor to built motor was i added 60% bigger injectors. I will say it is smokey when cold. Driveability is just like it was when it was stock. I can't make any claims in the mpg department. I only drive the truck 200 miles a year lol.
 

Bigdirtylbz07

New member
Feb 3, 2011
179
0
0
Northeast indiana
The reason I asked this is because of my mods below I'll be doin a built motor within the next few months with these pistons and adding 100% overs instead of 60% I'll be on the single a5k for a while until I come up with a good compound charger to match it it I'll be drivin the truck almost everyday and wanted to know what a good comp.ratio would be