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Search found 437 matches

by skinny z
Thu Nov 26, 2020 9:56 am
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

Thanks, a big reason i don't rely on DCR as a thing is because it doesnt give me the information i need. ...both cams are the same size, only difference is intake centerline. Could you load the 632 on pump gas? why did the 632 make almost 300 more hp granted the dynamic compression ratio is junk? I...
by skinny z
Thu Nov 26, 2020 9:43 am
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

Thanks, a big reason i don't rely on DCR as a thing is because it doesnt give me the information i need. ...both cams are the same size, only difference is intake centerline. Could you load the 632 on pump gas? why did the 632 make almost 300 more hp granted the dynamic compression ratio is junk? I...
by skinny z
Wed Nov 25, 2020 9:44 pm
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

Injector timing, valve timing, ignition timing, combustion shape torque management etc. Its amazes me how little people are willing to understand just to be stuck in the stone age. Thats why threads arent like they used to be. You get the same 5 people talking about 1980s technology when it comes t...
by skinny z
Tue Nov 24, 2020 10:16 pm
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

Not to pull off another ST OP's thread tangent (although I'm sure they would find this all useful), I made all attempts to meet the needs of an edgy engine. Blocked heat riser (or none in this case with an Air Gap intake), big radiator, big ass electric fan with good control. Even an open cowl hood ...
by skinny z
Tue Nov 24, 2020 9:22 pm
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

It's interesting to note, for me anyway, that one of the variables I neglected to consider was inlet air temperature. While I never experienced any overheating issues or even remotely had above average operating temps, with an open element filter case, I'd easily be drawing in air that may have been...
by skinny z
Tue Nov 24, 2020 10:51 am
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

If it makes the OP feel any better, using Pat Kelley’s DCR calculator my truck shows 8.4:1 DCR, and I’ve had absolutely no pinging issues on 91 octane pump gas. And...this is in Texas heat in a 4900 pound truck, with as much as 40* timing not counting the vacuum advance. My quench is a little tight...
by skinny z
Mon Nov 23, 2020 7:20 pm
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

BTW, if I was going to design a cam for your engine, with a 2,600 stall, and a 6,000rpm peak, this is what I would recommend Cam# HR72360-73360-110 276/284 @.006" 228/236 @.050" .576"/.576" Valve Lift w/1.6 rockers 110 LSA 107 ICL What spring and retainer would you recommend with that? Is Comps 269...
by skinny z
Mon Nov 23, 2020 2:25 pm
Forum: Engine Tech
Topic: Big Issues with Cylinder Pressure (DCR)
Replies: 84
Views: 2162

Re: Big Issues with Cylinder Pressure (DCR)

All right, DCR and cranking compression notwithstanding, in an engine that has a static compression ratio and cam spec that is what all here would say is borderline pump gas (for the application) at what point is output limited because the timing curve has to be so castrated in order to limit detona...
by skinny z
Sun Nov 22, 2020 9:35 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

I'm not saying unreasonable, but a lot more scienced out than just bolting some off the shelf parts together. The average guy wont get those results with shallow pockets and high expectations. I'm 100% in agreement with that. Hell, the 1.3 you alluded to in your previous post doesn't happen without...
by skinny z
Sat Nov 21, 2020 11:48 am
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

1.4 -1.45 for pump gas is what people should aim for,very few hit that target. For a NA unlimited engine EG - pro stock 1.65- 1.67 ft/lbs per cube wow!! 1.45 lbft/ci na? pump gas? not happy dyno? I'm happy when i get 1.3. For me aiming for 1.4 would be setting the bar pretty high. I mean 695lb ft o...
by skinny z
Fri Nov 20, 2020 1:51 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

That would be my (unanswered) question asked in a different way.
Isn't it overlap rather than LSA that's often the deal breaker between what gives the greatest output compared to something that "OK"?
by skinny z
Thu Nov 19, 2020 7:56 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

So, to follow that thinking, IF I have a 10.5:1 355 SBC AND I've got a well spec'd header that's open at the collector with a PipeMax calculated secondary length, all of which is strapped onto my dyno, which will make the greatest peak lbs-ft output? A 112 LSA or 108? All else is the same. Let's say...
by skinny z
Thu Nov 19, 2020 4:06 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

LSA notwithstanding but isn't it the overlap that is a defining characteristic? Obviously intrinsically tied into the LSA along with duration but the separation angle in and of itself isn't the whole picture. That said, it's been put forward here, with great debate, that certain engine profiles (an...
by skinny z
Thu Nov 19, 2020 4:04 pm
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

Maybe drifting a little off topic but what if the goal is the most lbs-ft per CID? Not the broadest or "area under the curve" but the greatest peak? (All else being equal)
by skinny z
Thu Nov 19, 2020 11:25 am
Forum: Engine Tech
Topic: Small cams on 106-108 LSA’s
Replies: 47
Views: 2145

Re: Small cams on 106-108 LSA’s

LSA notwithstanding but isn't it the overlap that is a defining characteristic? Obviously intrinsically tied into the LSA along with duration but the separation angle in and of itself isn't the whole picture. That said, it's been put forward here, with great debate, that certain engine profiles (and...