hammertime

iTrader: (1)

I've been researching a bit, and I'm not sure I've found anything to specifically address this question. I've seen several posts about what is considered the 'accepted safe DCR' for LS1/LS6 engines, most around ~8.5:1 for 91 octane and around ~ 8.7-8.8:1 for 93 octane fuel.

My questions are the following:

As most, my questions are covering an agenda, so I'll now address my specific example. I am considering an LS2 conversion in a G-body car that could tow as much as 4000 lbs trailer and gear. Given this would be a multipurpose vehicle (read: toy) I would still like to get the most performance possible unloaded, while not compromising the ability to tow a few times a year. A 4.10 or 4.30 gear and M6 should give plenty of torque multiplication, and help to avoid detonation, but close attention to the tune and KR would be addressed. Plans include AFR 205 heads, proper quench, and cam to be determined.

Am I ?

Thanks in advance for your replies...

Stang's Bane

iTrader: (22)

IMHO, the DCR term is thrown around way too much. DCR is not God of engine specs, it is a by-product of the proper valve events....


My advice would be to call the guy you quote in your sig and talk to him about it. He can explain it much better than any half-*** attempt I could make.

Alvin

iTrader: (2)

Thank you... If it wasn't for intake tuning and wave dynamics IVC would happen at BDC exactly. IVC is chosen for best cylinder filling.. not because compression is too high.

Old SStroker

You are an optimist. I'd say less than 50% of the time based on the cam numbers I see. Too bad, isn't it?

hammertime

iTrader: (1)

I really do want to come back to this, but I realized after reading the responses I had never made the time to read through the Camshaft Discussion I, II & III threads I marked in my Favorites so long ago.


I'm not promising an intelligent response, but I think perhaps I could have worded the questions posed above a little better. In short:

If I plan to tow with an LS2 and a manual trans, what is a safe Static Compression with an IVC of 42* ABDC (either a 224 Intake Lobe on a 110 ICL, or a 228 Intake Lobe on a 108 ICL).

One of my concerns is the Chamber size on a Large Bore AFR 205, as it seems to place the Static Compression rather high with a .040 gasket for the best quench, even unmilled, if the calculator I'm using is correct.

Old SStroker

You need to let a a pro design your tow/toy engine. It's a lot more complicated than "a 224 Intake Lobe on a 110 ICL, or a 228 Intake Lobe on a 108 ICL.

Stang's Bane had some pretty good advice. My guess is that you don't want that kind of advice. That's too bad.

hammertime

iTrader: (1)

That's not necessarily true, I'm just too hard-headed to admit what I don't know. That, and I don't think its right for me to waste someone's valuable time on something I'm pondering.

I would like to understand more about the process, but I'm stuck in the deep tech part of Cam Discussion II.

Stang's Bane

iTrader: (22)

I used to be like that also. Now, I will call Bret and ask him just about any off the wall **** I can think of. Granted. I have spent my share of money with him, BUT I have learned 10x the amount I have spent. Have him grind you a cam, it may cost a couple of $$ more than one of the off the shelf grinds, but you can learn more from the conversations than you can pay for.

Back to your original question. Honestly I believe if you make sure your SCR is at a decent level, your DCR will come out in the wash. I wouldn't lose sleep over the DCR, it is way overhyped

Stang's Bane

iTrader: (22)

Thank's Jon. Usually I am known as the "bad influence"