Question on Power difference between high compression and low compression N/A engines
Oct 7, 2009 | 11:49 PM
#42
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GFYS and STFU
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From: Here and sometimes there too.
Well...I think people will be shocked at how much compression really helps! 
I had a fun day! Drove out to EFI University and got my truck tuned by Justin, Reynaldo and Art were also there which was cool! Rey has a turbocharged SS that puts out north of 550rwhp, and Art has a badass N/A SS, both of them are red and both of them are freaking sweet!!
Anyways, since Justin was playing with trucks that had alot more power than me I decided to give him a break and let him tune my turd!
I was thinking/hoping for around 290 rwhp and justin was thinking more like 270rwhp due to the low compression. He tuned a 8.8:1 408ci motor and was only able to get 296rwhp out of it if I remember correctly because of the lack of compression and because of that he wasn't expecting much past 270rwhp for mine.
We never did a baseline tune because the truck was running really really lean when I got there but on the first recorded pull after some tuning was done we got 255rwhp which surprised him that it was so high right off the bat. After an hour or so of tuning we were both shocked when it put down 316rwhp!
More than either of us expected so 
to Justin!
Recap on the drivetrain...
1) Forged 366ci motor
2) 245cc WCCH stage II heads
3) Edelbrock ProFlo XT
4) 76lb injectors
5) LT headers and no cats
6) 218/218 114 LSA cam
7) 8.8:1 compression
8) FLT lvl 5 4L80e
Here's a dyno graph for those curious about the delivery...
1) Red graph is with cut-outs opened
2) Green one is with cut-outs closed
I think most of the gain over what was expected is due to the intake and the large heads.
So... here's a disclaimer for those expecting more out of this set-up (which I know is like 95% of you
), this motor has made ~750rwhp/rwtq (~1000fwhp) on 17 lbs of boost, so the motor is stout when used how it was intended to be used and that is when it see's boost. I could probably sit on the intake and fart and this engine would make more power, that's how much it loves boost. 
Being the case this is a good measuring stick on how a low compression motor reacts when not in boost!
Then again I did build this truck myself so there's always the possibility that I did something wrong!! So if your not happy with the results blame the guy who put the truck together! 
Here's two vids of the truck on the dyno, neither or which do the exhaust note justice, however with the cut-outs open I had to move the camera outside because the mic just went crazy and just gave up trying to record it!!
Cut-outs closed, running through a 24" magnaflow and a Dodge Ram 1500 Resonator (sounds pretty damn good actually!! )
http://www.youtube.com/watch?v=dZlSECvZyuw
Cut-outs opened, basically LT headers and 4 feet of 3" pipe for each bank. Was too loud to film inside, everybody that had legs left the building as well and the only sucker left inside was justin with earplugs.
http://www.youtube.com/watch?v=ezTy5d5Kklo
I had a fun day! Drove out to EFI University and got my truck tuned by Justin, Reynaldo and Art were also there which was cool! Rey has a turbocharged SS that puts out north of 550rwhp, and Art has a badass N/A SS, both of them are red and both of them are freaking sweet!!
Anyways, since Justin was playing with trucks that had alot more power than me I decided to give him a break and let him tune my turd!
I was thinking/hoping for around 290 rwhp and justin was thinking more like 270rwhp due to the low compression. He tuned a 8.8:1 408ci motor and was only able to get 296rwhp out of it if I remember correctly because of the lack of compression and because of that he wasn't expecting much past 270rwhp for mine.
We never did a baseline tune because the truck was running really really lean when I got there but on the first recorded pull after some tuning was done we got 255rwhp which surprised him that it was so high right off the bat. After an hour or so of tuning we were both shocked when it put down 316rwhp!
More than either of us expected so to Justin! Recap on the drivetrain...
1) Forged 366ci motor
2) 245cc WCCH stage II heads
3) Edelbrock ProFlo XT
4) 76lb injectors
5) LT headers and no cats
6) 218/218 114 LSA cam
7) 8.8:1 compression
8) FLT lvl 5 4L80e
Here's a dyno graph for those curious about the delivery...
1) Red graph is with cut-outs opened
2) Green one is with cut-outs closed
I think most of the gain over what was expected is due to the intake and the large heads.
So... here's a disclaimer for those expecting more out of this set-up (which I know is like 95% of you
), this motor has made ~750rwhp/rwtq (~1000fwhp) on 17 lbs of boost, so the motor is stout when used how it was intended to be used and that is when it see's boost. I could probably sit on the intake and fart and this engine would make more power, that's how much it loves boost. Being the case this is a good measuring stick on how a low compression motor reacts when not in boost! Then again I did build this truck myself so there's always the possibility that I did something wrong!!
So if your not happy with the results blame the guy who put the truck together! Here's two vids of the truck on the dyno, neither or which do the exhaust note justice, however with the cut-outs open I had to move the camera outside because the mic just went crazy and just gave up trying to record it!!
Cut-outs closed, running through a 24" magnaflow and a Dodge Ram 1500 Resonator (sounds pretty damn good actually!! )
http://www.youtube.com/watch?v=dZlSECvZyuw
Cut-outs opened, basically LT headers and 4 feet of 3" pipe for each bank. Was too loud to film inside, everybody that had legs left the building as well and the only sucker left inside was justin with earplugs.
http://www.youtube.com/watch?v=ezTy5d5Kklo
Last edited by Spoolin; Oct 8, 2009 at 02:25 AM.
Oct 8, 2009 | 12:23 AM
#43
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Joined: Aug 2008
Posts: 842
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From: East of the east bay CA
Can't wait till you spill the beans on this, but I know it's going to haul 
Oct 8, 2009 | 12:19 PM
#48
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GFYS and STFU
iTrader: (8)
Joined: Jan 2007
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Likes: 4
From: Here and sometimes there too.
I wanna say it is a DynoLog...
At first I didn't think much of it (not that I'm a dyno guru at all, far from it really) But this thing has all the bells and whistles on it and is also a load bearing dyno. It was pretty impressive to watch Justin use it. He was able to plug the dyno into his laptop at one point so all the data from the ECU and all the data from the dyno were all input into EFILive and it made tuning for him much easier if I understood what was going on correctly.
If you notice the sheet also says my displacement was 0.0! I am thinking about boring it out maybe a little more, you think 0.1ci would help me, add a little torque maybe?
I've been on a dynopack and a dynojet before and
At first I didn't think much of it (not that I'm a dyno guru at all, far from it really) But this thing has all the bells and whistles on it and is also a load bearing dyno. It was pretty impressive to watch Justin use it. He was able to plug the dyno into his laptop at one point so all the data from the ECU and all the data from the dyno were all input into EFILive and it made tuning for him much easier if I understood what was going on correctly.If you notice the sheet also says my displacement was 0.0! I am thinking about boring it out maybe a little more, you think 0.1ci would help me, add a little torque maybe?
I've been on a dynopack and a dynojet before and
Oct 8, 2009 | 12:35 PM
#49
I wanna say it is a DynoLog... At first I didn't think much of it (not that I'm a dyno guru at all, far from it really) But this thing has all the bells and whistles on it and is also a load bearing dyno. It was pretty impressive to watch Justin use it. He was able to plug the dyno into his laptop at one point so all the data from the ECU and all the data from the dyno were all input into EFILive and it made tuning for him much easier if I understood what was going on correctly.
If you notice the sheet also says my displacement was 0.0! I am thinking about boring it out maybe a little more, you think 0.1ci would help me, add a little torque maybe?
I've been on a dynopack and a dynojet before and
At first I didn't think much of it (not that I'm a dyno guru at all, far from it really) But this thing has all the bells and whistles on it and is also a load bearing dyno. It was pretty impressive to watch Justin use it. He was able to plug the dyno into his laptop at one point so all the data from the ECU and all the data from the dyno were all input into EFILive and it made tuning for him much easier if I understood what was going on correctly.If you notice the sheet also says my displacement was 0.0! I am thinking about boring it out maybe a little more, you think 0.1ci would help me, add a little torque maybe?
I've been on a dynopack and a dynojet before and
