by raceman14 » Wed Mar 07, 2012 3:57 pm
mnmatt,
I was blown away by your flow number until I read you did not use the carb and manifold ??? Why not? You might see a big difference especially at part throttle. Hmmm...wonder what it would do if you mounted your carburetor backwards or maybe even sideways, naw prolly not cause nobody has ever made a spacer for it, it must not work...
I read the first couple pages of posts and I am not into pissing contests or arguing theory or physics. I can tell you for a fact I have spent $500K plus of my own dollars on plate stuff and even after all that some of the stuff we did to make power does not obey what you think physics would tell you.
As far as some of the best guys to build 350-2bbl engines you would have guys like Wayne Collie, Jack Tant, Kevin Blanks, Brad Thrower, Keith Roberts, Keith Dorton, and I forgot the guy from VA that was real good on the carbs and engines I think it was Wally Duncan??? I saw a lot of their stuff as a NASCAR tech official at Lanier Raceway over 3yr period. I had customers run against their stuff both winning and losing. This stuff for NASCAR had to run 2101 on a Chevy, rules later allowed open plenum Weiand low-rise and a 2975 and whatever the Edelbrock 2bbl maniflold was. I got them sitting on a shelf but don't recall the number.
Most of them guys are not CPU guys or web posters and some are retired. Each of them had some different things they did to get up to say 425hp. In each case it was a package of ideas they put together around maximzing the pull on the carb.
I had the luxury of tuning those engines in the car with an inertia dyno capable of real time data acquisition. Although the standard program did not utilize all of the data gathered, the well advanced Superflow program allowed you to pull any data you wanted to and make your own channels up to 8 on my dyno. Now days you can have as many as your wallet can afford. I still use 8 channels and that is plenty for what I look at.
Some folks promote use of smaller duration cams for lower rpm applications, low overlap cams to minimize exhaust scavenging on the intake, & high compression to maximize what air you do get into the cylinders.
After a lot of testing and a pretty big mistake, I blew our best plate engine ( SB-2.0 ARCA ) on the dyno at Gibbs. Mark Cronquist, Jason Line, Matt Bienemann and Joe Hornick were helping me out as I bought 3 or 4 cars and engines from JGR and was kind of like the "po-boy" they liked helping ( I only mention the names because they were friends of mine and I don't think that is name dropping in that case, many of the nice folks on here and 4m question my points of reference so there it is ).
The engine did not actually blow-up like you think but in measuring blow-by, we found out we killed the rings ( 2-ring pak ) by leaning out the engine too much. Only thing I had left in my trailer was a 9:1 SB-2.0 that had been running in BGN in one of the cars I bought 105"WB to cheat up and stretch to a 110" ARCA car. Back in the day that was one of the ways of making an intermediate car fly...
Anyway, all we did was bolt the BGN engine on the DTS cart, run it to get a baseline and then we swapped the spider off the plate engine to the BGN engine. WOW, the increase in TQ and HP was pretty amazing not only to me but everybody else. There were a number of other things inherrent to that engine that kinda revolutionized my Plate Program as well as plate stuff @ JGR.
Bottom line, compression by itself is not all it is cracked up to be because for every action there is an equal and opposite reaction that can cause problems to the system.
I can tell you this related to any intake limited system be it 350-2bbl, crate engine, plate engine, & restricted intake engine; The deceleration or cut ( as they call it now with EFI ) can contribute 100-200 usable HP the the Race Car on the track.
That is one of the major reasons why Super Bike riders take a couple years to learn to ride Moto-GP bikes and Indy driver have a hard time with F-1 cars...They have more than double the HP under deceleration therefore having the ability to have more usable corner speed which is what any race vehicle needs to be faster than the next guy. In my world I call it Inertia HP, it is there and it is free if you know how to pick it up and it does not require cheated up parts, more cam lift or duration, more compression etc.
There are a couple of my customers out there running Ti-rotors and you will see them throwing sparks in the corner, and no it is not traction control, it is trail braking to allow the engine to free-wheel and maintain power without binding the engine down. If you can access 200ft# TQ earlier and faster than your competition this translates to almost double at the rear wheels or 400# more wheel torque, you'll see them hammer down and lift the left front and sometimes both if the track is hammer down. Yup, even in 2-bbl Limiteds and Crates.
Just my view on how to deal with intake restrictions...
The next step in this program is taking the system past the rev-limiter or choke limiter to huff the engine into a mode where you load the exhaust system with raw fuel and the concuss it in the middle of the corner and use the 600-800-1000ft/# peaks it creates to jerk the car off the corner, you just gotta make sure she is pointed straight before all that stuff starts happening or there will be a big'ole mess.
More is always better!!! Most of the time.
