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Looking for missing power after 122HH upgrade...

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Old Jul 21, 2008 | 02:48 PM
  #71  
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Originally Posted by zippy
A high boost supercharger will be in power enrichment constantly when driving on the street.
Can't disagree with anything you said, but am curious about this. Are you saying that it will be in power enrichment even at part throttle, as in cruising at highway speed, or when accelerating at low boost levels as well as high boost levels?
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Old Jul 21, 2008 | 03:56 PM
  #72  
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If you have a smaller compressor unit doing the job of a bigger unit this can happen. When you have to spin a blower super fast to make the boost level you want it can make it come into boost very early (as low as 35% or so). After you install your 8" crank pulley, log your truck down the highway with the cruise set and check how often you go into p.e..
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Old Jul 21, 2008 | 08:28 PM
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Originally Posted by zippy
That's a bit of a different order in making power than I've always used. You would first decide on how fast you want to go (dyno numbers don't matter unless that's your only goal). Next decide on how many cubic inches you intend to use. Next pick your boost level required to make the power desired to run the number you are looking to get with that cubic inch and your drivability. Don't pick a boost level based on what's cool or how high you want to see the gauge go to. If you had a 5.3L on 8psi of boost, your new 6.7L doesn't need to make 15psi to make you happy... Boost level is also going to be different for drivability if you are turbo or supercharger. A high boost supercharger will be in power enrichment constantly when driving on the street. A high boost turbo will have plenty of lag, but won't have the issue as bad with being in power enrichment as often. From there, pick your boost maker/compressor based on the size of unit required to stay in it's efficiency range at the desired airflow/boost level. After you pick your unit, select your compression ratio. Higher compression for lower boost levels and better drivability. Higher compression will bring a turbo into boost quicker and keep a supercharger out of boost longer (less throttle to move the truck means less power enrichment time required). If your stuck to using one compressor than your compression needs to match the efficiency range of that unit such as with a Radix style. At 8-10psi they are in their sweet spot and tend to run stronger with more compression. Race setups are great with low compression and high boost. Street setups are better with lower boost and higher compression. Timing is certainly not something I'd put ahead of chosing compression as it is a variable that is easily changed with the touch of the laptop, grades of fuel, meth injection, temperatures including IAT's, etc. Cam timing is a well researched item and yet I often see setups going very fast with what 50 others would think is the wrong cam for the setup. I see people spend forever picking a cam all the while someone else picked an off the shelf grind and ends up .2-.3 faster than them with about the same mods. Pick the duration by the rpm you need to run to make your desired power level, lift by head flow numbers, then go for LSA, ICL, ETC.

We dyno'd a truck friday that made 516RWHP with around 9psi (has no gauge, but last time we put a gauge on it that's what it made). That is an LQ9 with LS6 heads and LS6 cam, shorty headers, full 2 1/2" exhaust with cats, Volant intake, and Rotrex. It also has heavy 20" wheels and 305/50R20's. No special picked cam, standard heads, no meth, pump gas, etc. This truck has even trapped 117mph in this form.

I was mearly stating that there are three things that make power, and I named them in the order in which one makes more than the other. So in a way, you can build a combo that way. It seems to work for me everytime.

R
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Old Jul 21, 2008 | 08:32 PM
  #74  
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Originally Posted by Rick@Synergy
I was mearly stating that there are three things that make power, and I named them in the order in which one makes more than the other. So in a way, you can build a combo that way. It seems to work for me everytime.

R
Cool, I understand your point.
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Old Jul 21, 2008 | 08:35 PM
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Here is another example. Take my truck. I run about 17-18 for timing up top. For the cam I run, I should have a few more degrees to be optimal, but I dont want to push it. So I can either drop compression down to match the cam a little better for timing purpose, or change around the cam profile to not require as much.

As it sits, using this method, the motor is a 5.3. Compression is somewhere about 9.4 I am guessing. Maybe 9.5, who knows. Anyways, the truck makes 850 on my dyno @18psi. Thats about 2.6-2.7 hp per cube. Thats a pretty good number. Now if we look at flywheel we could say it makes about 950? So now thats about 2.9 per cube. Its a combo of so many things. Simple though. Just boost, the right timing and the octane to keep it there. Thats all. The rest of course is in the system on how well the FI system is designed of course.

R
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Old Jul 24, 2008 | 11:48 PM
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Any progress?

R
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Old Jul 25, 2008 | 10:55 AM
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Cam was delivered yesterday...waiting for OD pulley set.

I've decided to install the pulley set first since the target of the project was making 10 lbs boost.

Then follow with the cam, to see if the more aggressive duration and tighter overlap makes more efficient use of that boost.

Last edited by GoatChs; Jul 25, 2008 at 11:03 AM.
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Old Jul 25, 2008 | 11:37 AM
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Originally Posted by GoatChs
Cam was delivered yesterday...waiting for OD pulley set.

I've decided to install the pulley set first since the target of the project was making 10 lbs boost.

Then follow with the cam, to see if the more aggressive duration and tighter overlap makes more efficient use of that boost.

Again, more demand on the blower just means higher inlet temps.

Rick
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Old Jul 25, 2008 | 11:46 AM
  #79  
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Agreed...it will raise intake temps.

And if it responds poorly its only another $100 for a larger 8-rib SC drive pulley...and I still get the benefit of the 8-rib belt. One of the most affordable "fixes" I can make.
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Old Jul 25, 2008 | 12:02 PM
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Isn't the 8 rib conversion really expsensive to start with though???

I agree with you Rick, even if it dyno's better I'm not sure how much faster it'll actually be. The IAT's will just climb faster. A more agressive cam will only compound that. I've seen some good numbers out of the highly spun up MP122's on the dyno, but I'm waiting for the same out of the track numbers. Make sure to log the truck on a run to check for high IAT's past the 1/8 mile. Losing up top isnt a good trade off for more in the beginning.
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