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Search found 12194 matches

by MadBill
Fri Sep 18, 2020 4:46 pm
Forum: Engine Tech
Topic: Specific Torque
Replies: 6
Views: 349

Re: Specific Torque

David's assessment is absolutely correct, but lb-ft/c.i. has the advantage of being just a single division operation away from the most readily available raw data. There are other B.M.E.P. factors however, such as the difficulty of attaining a given value at say 15,000 RPM vs. 5,000 and the effect o...
by MadBill
Thu Sep 17, 2020 12:03 am
Forum: Engine Tech
Topic: Specific Torque
Replies: 6
Views: 349

Specific Torque

<EDIT> OK, so now I see the 'Similar Topics' threads I should have checked for first, but the dubious data in my last paragraph still invites comment. :oops: HP per cubic inch in well-developed race engines can vary widely due to many factors, but specific torque is much more constrained. 1.6 lb-ft/...
by MadBill
Fri Sep 11, 2020 10:54 pm
Forum: Engine Tech
Topic: Exhaust flames - running lean or just high temp?
Replies: 13
Views: 729

Re: Exhaust flames - running lean or just high temp?

Exhaust is red hot indicating late ignition timing. Probably due to too much boost and trying to prevent detonation. Combine that with too rich a mixture to equally prevent detonation and that is what you get. They are burning rubber - so retard ignition timing is from soft rpm limiter. Without sof...
by MadBill
Fri Sep 11, 2020 10:18 pm
Forum: Engine Tech
Topic: Damper hub question
Replies: 6
Views: 445

Re: Damper hub question

A crankshaft damper works on torsional vibrations so its distance from the front main is pretty much irrelevant.
by MadBill
Tue Sep 08, 2020 11:40 pm
Forum: Engine Tech
Topic: Jetting question
Replies: 7
Views: 422

Re: Jetting question

In my experience, most basic unmolested Holleys trend rich at high RPM, in which case you might have to jet down for the new combo. I'd start with what worked best with the current engine.
by MadBill
Mon Sep 07, 2020 11:51 pm
Forum: Engine Tech
Topic: oilless engine
Replies: 17
Views: 840

Re: oilless engine

Kevin Johnson wrote: Thu Sep 03, 2020 2:21 pm..
https://www.nrel.gov/docs/legosti/fy98/24433.pdf

Schumacher, L. (1995). The Physical and Chemical Characterization of BiodieseVLow Sulfur
Diesel Fuel Blends. NBB # 52019-1. Jefferson City, MO: National Biodiesel Board.
Encyclopedia Johnson delivers yet again! \:D/
by MadBill
Fri Aug 28, 2020 10:01 pm
Forum: Engine Tech
Topic: Dominator - can't even get it to idle
Replies: 103
Views: 4142

Re: Dominator - can't even get it to idle

No, I'd follow this path: 1. Disconnect the secondary link. 2. Size the primary main jets to achieve desired high speed cruise AFR*. 3. Size the primary P.V.C.R.s* to achieve best power/desired WOT AFR. *If they are not screw-in, you can have them converted or drill them larger (a couple of thous at...
by MadBill
Fri Aug 28, 2020 9:33 pm
Forum: Engine Tech
Topic: Dominator - can't even get it to idle
Replies: 103
Views: 4142

Re: Dominator - can't even get it to idle

... Cruise could do with a bit of richness also. low speed cruise is quite good at 14 AFR (under 20 miles an hour). 20-45 MPH afr jumps up to 15 so I have to get that down... I think I'll take the secondaries back up to 100 and bump the primaries to 90 for richer cruise With a mild cam 15:1 cruise ...
by MadBill
Fri Aug 28, 2020 8:49 am
Forum: Chassis / Suspension / Body
Topic: Question - Improved Camber Curve
Replies: 20
Views: 368

Re: Question - Improved Camber Curve

You'll have to research the subtitles (lots of info out there), but almost everything you're planning, including caster changes, affects it and the effects especially for roll oversteer can be pronounced. Some race car builders won't settle for more than say 0.010" toe change through perhaps 5" of s...
by MadBill
Thu Aug 27, 2020 10:26 pm
Forum: Chassis / Suspension / Body
Topic: aerodynamic drag and body style
Replies: 3
Views: 206

Re: aerodynamic drag and body style

I don't think you'll find any measurable benefit, especially considering that you're running brackets. A few decades ago streamlining was explored by a number of Top Fuel teams. They found that the few extra pounds of bodywork more than cancelled out any potential gain. https://www.hotrod.com/articl...
by MadBill
Thu Aug 27, 2020 10:02 pm
Forum: Chassis / Suspension / Body
Topic: Question - Improved Camber Curve
Replies: 20
Views: 368

Re: Question - Improved Camber Curve

With all the suspension mods under consideration, at least one more parameter will need to be addressed, i.e. bump steer.
by MadBill
Thu Aug 27, 2020 7:25 pm
Forum: Engine Tech
Topic: 5.3 LS max compression
Replies: 8
Views: 395

Re: 5.3 LS max compression

David Redszus wrote: Wed Aug 26, 2020 4:23 pm Octane changes from state to state based mostly on elevation.
One of the axioms of the refinery business is "Never ship gasoline downhill." I once fueled up an '82 Oldsmobile in Flagstaff AZ (el.~7,000') and 3/4 of the way back to Phoenix (el. ~1,000') it started pinging... #-o
by MadBill
Wed Aug 26, 2020 7:14 pm
Forum: Engine Tech
Topic: gm 602 crate headers
Replies: 5
Views: 233

Re: gm 602 crate headers

Just ensure the IDs are not too scaly. Smokey Yunick told of encountering a mysterious 20 HP power loss during an all-night dyno session. They checked and checked, changed parts, etc. Finally they stumbled on the fact that somewhere along the line the headers had been switched with another identical...
by MadBill
Mon Aug 24, 2020 9:29 pm
Forum: Engine Tech
Topic: Tunnel Ram Carb Confusion
Replies: 43
Views: 1464

Re: Tunnel Ram Carb Confusion

There's been a ton of progress in the last few years re valve springs and hydraulic rollers. The right choices would probably help with your current combination and would be essential for your target RPM.

BTW, With no other changes a 1,000 CFM carb would likely be worth 25+ HP and a few hundred RPM.
by MadBill
Mon Aug 24, 2020 7:06 pm
Forum: Engine Tech
Topic: Piston/Deck height measuring confusion !!
Replies: 44
Views: 923

Re: Piston/Deck height measuring confusion !!

Eagle1903 wrote: Mon Aug 24, 2020 6:07 pm...
I think I found my interpretation mistake. My zero reference was the block gasket surface, zero deck.
Yes, well I did mention TDC at least five times... #-o