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650HP Hard-Core Pontiac Stroker


http://www.carcraft.com/techarticles/ccrp_1012_pontiac_400_poncho_engine_build/index.html


ccrp_1012_14_o+pontiac_400_poncho_engine_build+cv1_roland_single_plane_intake.jpg

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Yeahhhhhhhhhhhhh!!!

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Me give up? NEVER!

In memory of our friend, gone but NEVER forgotten!



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Damn nice engine to b sure and some real power too, however, i'de b more apt to make that much and more by using a .030-.040 455@ 10-1 so as to b pmp gas friendly. This would b a relatively MILD and pmp gas friendly engine with maximun durability and driveability and produce roughly 1bhp per cube or 464bhp@ around 5500rpm; to that i would add a 2 stage wet plate nitrous oxide system w/ 100bhp on the 1st stage which i would launch on and an aded on 150 2cnd stage which i would engage at the 2cnd gear shift or as soon after launch as the chasis settled. That would b a total of 714bhp on demand and 464 under normal operating conditions, which is exactly how i have my TA set up. took a whole lot less time and expense to accomplish and makes on demand 64bhp more than this exotic 400 at fewer rpm.
While i am a spray JUNKIE due to my long history of experience with spraying BOPC engines as well as pretty much every other make, i understand that many folk do not use or want to use spray, most often because they know little if anything about it so they defer to the wives tales and horror stories they hear about spraying.
1st thing to understand is that a sprayed engine is still NORMALLY ASPIRATED. in order not to b notrmally aspirated one would have to somehow RAISE the inlet pressure above 1psi or 1 atmospherfic pressure as with a turbo or super charger. Sprayin an engine simply displaces an amount of what the engine would normally ingest thru its inlet with a mixture that is MORE OXYGEN laden@ 33% by weight and volume, vs all free air intake which at best will never exceed 14-15% by volume and almost never that much by weight(10-12% on average).
Spray is essentually a cleanup or something that maximizes thermal and volumetric efficiency of ANY ENGINE as in makes it completely fill the cyl on each intake and completely burn what is taken in during the combustiion cycle. This, in a fashion, limits the power boost one can achieve with spray to the max the physical capacity(CUBIC INCHES) of the engine dictates. NO matter what size or brand or even what configuration, all engies of the same cubic inch capacity have the EXACT SAME POWER PRODUCTION CAPABILITY. what explains the diffs in engines of the same size makin diff amounts of peak bhp is mere a function of each engines thermal efficiencyrate and its volumetric efficiency rate, given 100 per cent or even just equal thermal and volumetric efficiency rates each produces the exact same amount of power. an engine doesn't know what brand it is, it doesn't know its stroke, bore, cam numbers in terms of its ability to produce power, it only knows what size it is and what its inlet pressure is. There are but 2 ways to increase an engines power production capability, enlarge it, and or increase its inlet pressure. This explains the "no replacement for displacement" axium. You surely can SUBSTITUTE for a shortfall in engine size, but substitutes only suffices so long as a larger engine doesn't also employ them.
Spaying and boosting achieve the same end, increase power production. They do so in different ways....boosting increases power by increaseing the volume of air into the engine on intake cycle, which increases the amount of oxygen in same. Given the corresponding amount of fuel enrichment, the more air/oxygen u can get into an engine on intake the more power u can make. If u mix too much fuel in ur mixture u run fat(cold and dirty, of the heat yield of the fuel ur not gettin very much. Conversely if u do not mix in enuff fuel u run too hot/lean. Unsuspecting of most, fuel is not nessecarily what an engine operates on. It actually operates by heating as much oxygen as it can intake as hot as it can by maintenance of a fuel/air mixture that supports a burn as close to the verge of lean out as possible over the widest usuable rpm band width it can. The reason for this, of alll gases in air, the one which most violently expands with application of the least amount of heat is OXYGEN. Ur fuel is known as an accellerant. The act of compressing air heats it, thats how diesel engines operate, compression hgh enuff for the heat of same to ignite a fuel/air mixture, which then accellerates the heating process. with a gasoline engine u effectively need 2 accellerators instead of just 1, fuel AND spark. Sprayin achieves the same result by introducing more oxygen in each intake by way of replacing/displacing an amount of AIR, with a gas compound that is richer in oxygen than air is. As is oft said, therein lies the rub, that restriction limits ones power production capability to whatever is max for that size engine at 1 atmospheric pressure in the inlet if the engine were to achieve 100% thermal and volumetric efficiency rates. As i stated, the only way to exceed whatever that is would b to enlarge and or increase the inlet pressure of the engine. boosting effectively enlarges the engine by way of increaseing its intake capacity. More air intakes in the same amount of space and time on each intake stroke, more air brings in more oxygen, add the proper amount of fuel enrichment, mor power produced.
This explains why even if u have one or the other forms of inlet pressure boosters, introducing spray still offers a power increase. Boosting doesn't increase either thermal or volumetric efficiency, those factors are controled by the physical configuration of the engine. What boosting does is increase the amount on which the engine can effect whatever thermal/ volumetric efficiency rate it has; thus anything that also enhances the engines thermal and volumetric efficiency rates enhances boosted engines as well as normally aspirated ones.
As far as spray blowing up or wearing out ur engine faster, yea, it does, WHEN ITS ENGAGED, when it isn't it has NO EFFECT on the engines wear and tear factor....BESIDES, no matter how u achieve a power increase in any engine, same will always increase the engines wear and tear factor too. IE: u have an engine that has a TEAR factor of say 500bhp...lets then say u only make 400bhp of that w/o spray, but add a 150 shot; u just exceeded that engines tear factor by 50bhp every time u engage the spray, in which case the same thing is going to happen if u produce 550bhp from an engine w/ a 500bhp tear factor everytime the engine is actually producing 550bhp with or without spray. It follows then that there is really no such thing as a nitrous engine. an engine for nitrous expected to achieve 750bhp peak power is the same as any engine expected to achieve 750bhp by any means in terms of the durability factor u must build the engine to sustain under such a bhp load. Nitrous camshafts ?? Really no such thing as those either, simply put, whats now called a nitrous cam once was called a "cheater"cam, and then as well as now, widely used by stock class drag racers. Over the years the reference somehow got shortened to just "cam" after 1st being called a "3/4 cam" when the practice made it to the street, with a "FULL race" cam refering to much of what we consider a street cam these days, but was only seen in RACE CARS back then. What we now call a nitrous cam is essentually what was once called a cheater/3/4 race cam; that being a cam cut on close lobe center and close lobe seperation numbers. This shortens the amount of valve overlap, that amount of time in degrees of crankshaft revolution at which both valves or ALL valves in any one cylinder are off their seats. This BUILDS CYL PRESS, since the shorter the amount of time a cyls valves are off the seat, the more time in the compression stroke it has to fully compress less ur leak down factor only. The more cyl pressure u have at ignition, the more tq u make, the more tq u make, the more hp u CAN make and do so with ever fewer rpm used to multiply tq to achieve ur desired bhp factor, add a relatively LONG stroke and or a relatively LONG rod and u also increase dwell time at TDC( dwell time is that amount of time in degrees of crankshaft rotation that ur piston pauses at tdc and bdc to change directions). This will also result in a tq increase, as well as lower the rpm at which u make ur peak tq, again, makin so u need multiply ur tq by even fewfer rpm to achieve a desired bhp factor( NO REPLACEMENT FOR DISPLACEMENT).
Finally, other than the 301 with its offset from norm bore centers, all production pontiac V8 blocks have the same max safe cube potential....500", most stop at 496-498. and ALL but the 287- 301 were available in hgh nickel content H.O. or S.D. blocks, plus ALL Pontiac V8 Blocks whether they come w/ or w/o 4blt main are preset up to affix same, offered from the factory as a service part. If u want a stroker, whats the big deal about which of the 350-455 blocks u use to do so??? Right....non. One would expect that such experts with such expertise would know and consider that, but it seems that few do. Next, it seems that ALL Pontiac drag race builders want to instill some other more popular brands power production characteristic in a Pontiac engine, they wanna make em rev like a chevy, like the kind of gears that a chevy does, or a Ford, or Mopar. Even Pontiac themselves, as did Buick and Oldsmobile fiddled with the idea of crafting their heads like those of other makers, and all 3 produced hgh perf heads for their cars in production that in many ways mimicked heads of more popular brands. Ram Air IV and V Pontiac, W30 and W31 Oldsmobile, Stage I and Stage II Buick, and actually, all but the Ram Air V were real effective, the 5's were not as effective as they SHOULD have been because like Ford's Boss 302, 351 n 429, the engines they were on had too small bores and strokes to achieve an efficient port velocity unless u revd the snot out of em in which case they had a very short life indeed.
With my BOPC's, grunt tq monsters all, it been my experience that u just as quick for a lot less time and money if u take em, seek to increase peak tq and lower the rpm at which u do so, keep it loaded by way of TRACTION and not so much gear that u over multiply ur tq till u unload em, try to widen and flatten the power curve as much as u can, that time in rpm between peak BHP and peak BTQ. u want that rpm curve to b FLAT as is possible....Given that ur combination is compatible with it, one can go quicker with a 500bhp engine that has a 25-3500rpm power window than a 600bhp one that only has a 15-2500rpm pwr window and hgher up in the serviceable rpm range.
To win at Drag racin, its about as much tq as u can make as quick as u can make it and the traction to put same on the ground. BIG BHP numbers come at BIG rpm, espeially when ur multiplying a short fall in low rpm tq to achieve em. they will account for good mph but not nessecarily quick ET's. While BIG tq comes at a lower rpm and thus won't account for real big mph, it will account for a QUICKER ET than will an equivalent and hgher number units of bhp will. To accellerate at a good rate , especially from rest as we do in an SS 1/4 mile drag race, ur much better served with big tq n the traction to put it to the ground than big mph. Droppin ur et by way of big MPH puts one in the Catch-up, which is much better suited for hot dogs n french fries than drag racin IMHO.

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Dallas


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MERRY XMAS and a very hapy new year to you and th family Tango my friend, and may u all enjoy many many happy returns...peace b unto u.

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Dallas


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Merry Christmas to you too . I hope to see more of You Now and in the New Year . I have always Enjoyed your Threads nod.gif I Hope Santa Brings you some Good Performance Stuff  biggrin


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