GoatChs

iTrader: (7)

That's what I thought when it popped up.

ZO6Ted

IMO keep the heads and cam do exhaust. Fuel for E85 if possible then pulley.

GoatChs

iTrader: (7)

That sure seems to be the consensus so far, and certainly doable without any top end changes. I am sold on upsizing the exhaust--my Dyantech's have 1-3/4" primaries, which I think would be fine but not thrilled with the 2.5" collectors--really feel 3" would be optimal but it is what it is. I currently have the catted y-pipe but could switch to the Dynatech 6.0L non-catted mid-pipes (which does not have a connected y-pipe), add an x-pipe, Borla mufflers and tailpipes. Basically what I said above but getting rid of the cats. Alternatively, there is a very fine set of lightly used Kooks 1-7/8 LTs that might be had, and then a 3" out the back...no more worries of 2.5" collectors and pipes being a restriction. I need to get my engine builder to nix the 2.5" option for me. What's that old adage...measure twice, cut once? Why can't I ever remember that when I start my hotrod projects!

Here's another thought I had on-the-fly.... As I mentioned, I have a Volant CAI with the Volant snorkel, feeding through the stock MAF to the Magnuson air tube and a NW 90mm TB...again, the Radix j-tube is untouched. I was thinking about swapping in a Banks Duramax Ram Air box, modifying the Banks 4" intake tube (heat with a PVC pipe heater blanket and bend to shape) for proper alignment with the Radix j-tube and putting a getting a 100mm MAF in between. Could get the j-tube ported and modified for a 102mm TB as well. Doing the math in my head, that's probably around $1400-1500 with the TB & MAF purchase...sounds great except the $$$, I think that one won't be getting past the mental drawing board.

03sierraslt

iTrader: (22)

Are you DBC or DBW throttlebody?

Vortec350ss

iTrader: (20)

A couple problems.

First your ECL is 115
Second, your VE is 100, not 1. Also, at 10 psi I would have said 165 (10 psi is about 65% of atmospheric pressure on top of an atmosphere... confusing. whatever... just do it.)

The diameter I get is 1.92" with a length of about 40".

GoatChs

iTrader: (7)

You nailed it on the first two points...ECL is 115, thanks for catching that. I went back and extrapolated from ICL & LSA, and 115 is correct. And another good catch on the VE field entry...the calculator clears all fields when run so I refilled them in again to make a screen shot with data...I missed that it had automatically placed the decimal, however I did enter a VE of 100% for calculating. I get your math on the VE...but I'm not informed enough to know if it is correct. When I was trying to determine approximate VE on my engine I found THIS PAGE which provides a formula (Equation 7) that when followed indicates an approximate of 107.7%. I used the values of 553 hp and 5800 rpm from my last dyno values for this calculation, although in after thought I realize that my entry value represents the rwhp and the calculation is likely looking for bhp to eliminate the parasitic loss variables. I will run it again using rwhp plus 18% drivetrain loss, just for grins. But in any event, I reran with the 115 ECL value and and calculated VE and it increased quite a bit...much more like what I'd expect to see. Even with the RWHP value it strongly indicates that a 3" collector would be beneficial as it sits today, with no other improvements...who said learning can't be fun?!

Fortunately Santa knows that I've been good this year, and he's working on a very nice set!

GoatChs

iTrader: (7)

I really appreciate you guys' input...the exercise is educational and body checks assumptions that I tend to leap to when left to my own devises. After I get the 4L80e in, I think it would be very interesting to do a new baseline dyno then upgrade the exhaust and tune it on the dyno to see what was changed (gains/losses) in the HP & TQ curves. So, unless WWIII breaks out, that is the plan...exhaust with no other changes.

I guess the 3" collectors requirement precludes the 2.5" duals out the back. You guys mentioned both dual 3" and single 4"...is there a technical/efficiency advantage, or does it boil down to space and cost?

03sierraslt

iTrader: (22)

Vortec350ss

iTrader: (20)

Another variable you need to add back to your HP is blower drive loss.

558 HP plus divided by .8, and then add another 80 from the blower (just a guess). You are moving the air needed to make closer to 750-775 crank HP.

GoatChs

iTrader: (7)

I'll get a quote for each and go from there. I know a few good 3" mufflers but I've read and watched so many threads and videos of 4" that they are all running together in my head...somewhere I watched a vid of someone running a 4" Corsa Duramax muffler on their turbo gas rig, and as I recall it sounded a bit "hollow" if that description makes sense. I didn't really care for the sound much but, for me, a bigger concern than tone is drone...won't have it. Any experience with a good 4" muffler?

Dude, you've got some good info...I'm going to doing more searching, I bet there is a calculator out there that allows for "boosted" application data input.