GoatChs

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How about some mental bubble gum for my more experienced forum friends? I'm looking for some input/ideas for helping out my poor little MP122hh.

Here's the deal...based on the boost curve from my last dyno, my engine is out running my Radix MP122hh w/ 90mm TB (no porting on SC or TB). I've ordered a 2.8" pulley to replace swap the current 3.1, which will up the output but we all know that will also bring higher IATs and pulled timing. With the new 4L80e swap tapping my resources, I won't be upgrading the SC for a while and need to do something to get more out of current SC. The main engine specs include a LS6 block topped with untouched AFR 225 heads (72cc combustion chambers), a 222/228 556/571-114 cam (cam card pic attached), -7cc pistons, 4" stroke crank, a Volant CAI w/ snorkel and Dynatech LTs into catted Dynatech y-pipe and Corsa 3" exh with the Touring muffler. I have some ideas for improvement, and do have a couple of parts "in-house" from other projects that could be swapped in.

First, the cylinder heads... I think the AFRs are good heads but not sure the 72cc chambers, or the 225cc runners for that matter, were the best choice for my setup. I was thinking "free flowing" when I picked them, but now think that the AFR 205s with 65cc chambers would have been a better match to the MP122hh. I don't plan on buying another set of heads but I could have the 225s milled down to 65-67cc to help the MP122hh fill the chambers. Alternatively, I have a set of Absolute Speed (remember them?) cnc'd 241 castings that have not been milled (67cc) that flowed pretty good...those, a baby 226/230 cam and LTs made 405rwhp in my otherwise stock M6 GTO. I could even have those milled down to a 62-63cc chamber to allow the Radix to actually pressurize the cylinders.

Second, the cam... It's a Speed, Inc. SC1 grind (card below), and it would probably be ideal for the MP122hh in a stock-ish engine. But I'm wondering what a slightly larger cam could do to help with the flow into and out of the cylinders. I have a MTI (from MTI's first time in business...not the new shop) Y1 grind (other cam card below) that runs 236/242 601/610 113. I know that the 113 LSA is not ideal--should be in the 114-116 range--but the overlap calculates to be 50 degrees which is not too bad. And the lope would be so much sexier than the SC1.

Third, the exhaust... I think the Dynatech LTs are good to go but the two 2.5" cats into a y-pipe and 3" single out the back is not ideal. We have a pretty good custom exhaust shop close by and I'm thinking that he could cut right behind the cats and add a 2.5" x-pipe then into a 2.5" dual in/dual out 24" Borla ProXS muffler with tailpipes and turn downs dumping out on the passenger side ahead of the rear tire (similar to the Lightning). Would probably save a few pounds as well.

Almost lastly, fuel... I currently have the stocker in the tank, the Magna Charger inline pump and Alkycontrol meth injection. I really want to get rid of the meth...don't like relying on that to keep my engine from burning up, AND it is bad for the rotor coating. I know there are $1000+ dual in-tank setups, but I'm thinking about a GSS342 340lph in-tank with a boost-referenced Boost-a-Pump to bump the voltage under throttle.

And lastly, N2O... I also have a Harris Speed Works 90mm plate kit in the "warehouse" that has been waiting for this 4L80e swap. A 75-shot would certainly wake it up at the 660' as heat soak builds.

So, I know that this might seem like a lot of work to save not a lot of money, but as I said, the 4L80e tapped my "fun money" and now that I don't have to worry about grenading the 4L60 it's time to squeeze more out of the power plant. Let me know what you think...but please set your phasers on stun.

madmann26

iTrader: (7)

03sierraslt

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Vortec350ss

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I agree with what pat has said.

The cam isnt ideal. But I don't think its what I would change first. Luckily the AFR's have a more efficient exhaust port, so my guess is it's exhaling just fine.

I agree a more efficient blower would make the largest difference. Start by really uncorking that exhaust. ! 7/8" headers and 3" collectors with dual 3" or single 4" the whole way back. My opinion is if you are going to change cams and spend all the money on gaskets/fluids, and all your time doing it, make sure you get the right cam.

03sierraslt

iTrader: (22)

GoatChs

iTrader: (7)

Thanks to both of you for the feedback! And please keep in mind that I am discussing, not dismissing...it's all educational and appreciated!

I have meth, but not a fan of the potential for lean burn if the pump takes a poop, and the erosion effect on the SC rotor coatings...have seen pics of what it can do. I was just reading up on how to convert to E85 at this THREAD...from that it appears that Last Call has a good handle on the particulars. Will need to dig into that a bit more...it appears to be a solid solution.

From what I've been reading there is not a 450lph drop-in for a 2001 bucket? At least I have the return style so there is a little less work/cost involved. I just started reading up on the 450lph pumps with an eye toward E85 conversion...would cover me now and whenever I can afford to upgrade the SC.

GoatChs

iTrader: (7)

Ahh geez Margie... Looks like I have more reading ahead to figure out how to calculate primary and collector size requirement. In a quick search I did find an interesting and pertinent read on superchargers and VE (see below), so I'm sure I can find the answers. There's no refuting the exhaust...that's a given it's to restrictive, but I had not considered that the Dynatech's LTs may be too constrictive as well. Then again, why not...it is part of the overall "air pump" and all components need scrutiny.

And yeah, the best path to a proper camshaft is having one spec'd for the setup, but truth is I only plan to keep the 122 until I can afford a larger SC or "possibly" a Trick turbo kit. At that point I would get Pat Guerra (or another guru) to spec another one for me.

Here's a couple "seeds" I can plant...

After dumping good money after bad, my 04 GTO rear-mount turbo experiment never worked out as advertised by STS. So I decided I would go with a TVS2300...another item sitting in the warehouse that is my garage, waiting its turn. Is it possible to install that front inlet rear-cogged SC on my Yukon, without spending another $2k? Not that it has not crossed my mind, but just to tickle the idea a bit more...since I already have the turbo, wg, IC, etc, I could go with a Trick Turbo kit for the GTO and move the TVS to the Yukon.

Pat, I appreciate the heads up on the Kook's...PM me with what you would need to get for those. Colby
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How to Calculate Max Boost

Calculating max boost depends primarily on three variables. The max CFM of the blower, rpm where you want the boost to peak, and the displacement of the motor. This based on the same reasoning used to calculate needed carb CFM. The principle is that an engine is an air pump and it is easy to calculate how much air it pumps if you know the displacement, speed (rpm) and efficiency (VE) of the “pump”. You can ROUGHLY estimate max boost as follows. The 0.9 factor is the ~VE for the typical intake tract under non-boosted conditions. The number 3,456 is just a mathematical factor to make the units come out properly.

CID*rpm/3,456*(.9) = engine airflow requirement
((blower CFM/airflow required)*14.7) – 14.7 = boost

So, as an example if you have a 350 and a 1,000cfm blower and want to make peak boost at 6,000rpm:
350*6,000/3,456 = 607*.9 = 546
1,000/546 = 1.83*14.7 = 26.9 – 14.7 = 12.2psi is the approximate max boost at 6,000rpm with 1,000cfm.

You select pulley sizes to spin the blower to close to max impeller speed at the rpm where you want the power peak (primarily determined by the cam). Anything which increases VE will increase power but decrease boost. Lower VE will increase boost but decrease power. Anything that interferes with the blower output (especially inlet restriction) will decrease blower CFM and decrease boost and hp. An engine with a larger CID will see less boost and make about the same peak power as a smaller motor if the same blower is used and maxed out in each case. However, the larger motor will have a fatter torque curve and go quicker. Increased air density (cooler, drier, higher barometric pressure) will increase hp, lower air density will decrease hp.

Manufacturers web sites provide blower specs, including maximum CFM.

GoatChs

iTrader: (7)

I found a Header Sizing Calculator that provides primary tube length and diameter and collector diameter based on your data. Note that one of the criteria is volumetric efficiency (VE), and based on the research I did and the data required to determine that value, I doubt that .01% of us have an accurate value available. But generally it is accepted that a reasonably well spec'd supercharged engine can reach 100% efficiency--really well designed forced induction engines, such as Formula 1, can be as high as 130% VE. So with 100%+ VE being my goal I enter that along with the rest of my data and it came back with some interesting recommendations.Pretty small on both primary & collector diameters...

03sierraslt

iTrader: (22)

smokeshow

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The only thing CFM is good for is measuring flow rate over Niagara Falls.