Compression ratio

Frankin_truck

Member
Nov 22, 2013
147
0
16
What's everyone's thoughts on compression ratios for a full blown sled pulling engine dedicated puller. Been doing lots of research this topic seems to be lots of mixed answers. Some say high compression is free horse power but hard on parts others say stay low and run more boost. I know statics and dynamic compression ratio play a big part in this. I was thinking 15:1 would be good. Open to suggestions
 

gmduramax

Shits broke
Jun 12, 2008
4,072
248
63
Nor cal
I would say since it's a dedicated pull truck and you'll be limited by turbo I would run high compression.
 

Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
Mine is 15.5:1. That's what Mark Brovaik recommend when I built my motor. I did loose 40hp gained a little torque over my stock motor with air and fuel the same. That's was also with a stock appearing Danville 2.5 vgt charger.

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Frankin_truck

Member
Nov 22, 2013
147
0
16
Talked to a few reputable people in the duramax community 15-16:1 seems to be the general consensus. Turbo size seems to have a lot to do with
 

Harbin_22

Active member
Dec 4, 2010
3,858
7
38
Southern Indiana
I run 16.5:1 with around 85-90#'s boost from the triples. Blew headgaskets with standard H11 studs. Went to 625's and Oring heads, no problems for the last 10k miles
 

prostreeter600

Street rodder
Jul 18, 2010
893
7
18
Dallas Tx
Not to go against the grain but my build wound up with 14/1 forged Arias cause I got some good deals on here for the Pistons , cam , lifters and several other parts from a member that was getting out of the sport. Flirting With Disaster had sold him all the parts I believe . I was a little concerned at first but once I had it all together and running I can say I am very happy with the results . It's very responsive and pulls extremely hard . The only thing I notice is that the engine needs to come to operating temperature in order for it to run its best . It has a white smoke haze till it warms up a bit then it's clean . Tune 1 is clean driving thanks to Mark Broviak. I'm doing 3.42 gears in it in the next month or so to see if I can get it deeper into the 9s on fuel only . Best time to date was on Tune 4 spinning a bit out of the hole . Gentleman at FWD said the lower compression would allow for a better air charge .
 

duramaxzak

Wanna be puller!
Nov 22, 2008
2,431
14
38
Minnesota
I think the forged pistons expand more when getting to operating temp than cast do. I noticed also that my motor with Mahle forged pistons run cleaner when pistons warm up a little.
 

malibu795

misspeelleerr
Apr 28, 2007
8,236
550
113
42
in the buckeye state
DDP ran 19:1 in a 2.5 class...
I'd also spend little more time making sure bottom end was solid.
Compression=HP and increased turbo response

I've heard rumors of someone building a 20:1 dmax.. I've thought about it and putting it in my tow pig.