Kevin Shasteen

Hey Steve, Thanks for the vote of confidence. I've read where the intake ports on those Edelbrock cyl.heads are suppose to flow 216cc at .500 valve lift; with your choice of hyd.roller-should be good for 465hp..providing again-your only restrictions are the cyl.heads & not the intake nor exhaust system. Those cylinder heads should be great for the street; the ports are not too large where airflow will be too minimized at low rpm's (all dependent on your camshaft choice-hyd.roller should be more user friendly) nor are they too small that high rpm will be diminished. The max RPM depends on the [minimum port volume]; unfortunately this is not a number that mfg's lists. Its moreso something the individual has to measure. Simply measure [Height x Width] to obtain [sqaure inches]: be sure you measure the port exactly adjacent to where the pushrods go thru. Once you've got that number (in square inches) use this formula where Limited Port Volume = LPV: Max Rpm = LPV x 184,136/Bore^2 x Stroke BTW: this formula is only good for a Hydraulic Roller. Your tires are 23.68"Tires in Diameter & should yield you 117.46mph @ 6500rpm's and 108.43mph @ 6000rpm's. It all depends on the actual torque/hp your engine puts out and of course that was at a 1:1 trans gear ratio with you being in 4th gear. I wish I could build a 377; I like the idea of a "Rev-Happy" SBC V8; especially in a light car like the Z. About Quench-the best article I've read was here recently. It was on "Speed-o-motive's" site under their "Engine Building Tip's": Lone posted an answer to someone here in another forum & gave the site as one to look around...so I did. I really like their "Engine Building Tips"...it was very informative. Do a search on the web for "Speedomotive"-you'll go right to it. They did say that if you're using hipo parts w/steel rods & steel crank you can deck your block to .010 or a "0" block deck as long as your head crushed head gasket thickness remained .035" which was the minimum thickness you could get away with providing you kept your rpm's under 6500rpm. You can email me your article by clikcing on the "Letter" icon at the top of one of my posts as I'ld be happy to read it...always looking forward to furthering my knowledge at someone else's hard earned experiece. Kevin, (Yea,Still an Inliner) [ June 17, 2001: Message edited by: Kevin Shasteen ]

What RPM are you wanting your engine to come in to [peak power] at(?); 5500 or 6500rpms? To know your RPM's at the 1/4 I need the full tire measurement 190/60/14's ect, ect. A 2800lbs car w/400 RWHP will click the 1/4 mile @ ET = 11.14; while a 2800lbs car w/350 RWHP will click the 1/4 at ET = 11.65 while 300 RWHP will gain you a 1/4 mile ET = 12.26 If it's 5500rpm-then you'll need a cylinder head whose Minimum Port Intake Volume equals 1.72 sq.inches. If your peak power is 6500rpms then you'll need a Minimum Port Intake Volume of 2.0 sq.inches. The Port I'm referring to is the intake port on the cylinder head/more specifically-right where the air enters the cylinder head. (Just tell your engine builder what you need-or the tech line/they should know what you're talking about). What static compression ratio are you wanting? I used Brodix -8 heads which flow at 220cc @ .500 lift at 25*Degrees Pressure Drop. Using those figures w/a Hydraulic roller they should be good upto 475 HP: then your power will begin dropping: RPM's will still continue-but power will begine dropping. This assumes the only restrictions are the cylinder heads & not the intake/exhaust systems! As for compression ratio (are your piston's flat top's? slight pop-up's w/slight valve relief's? Lets say you chose a cylinder head w/67cc; add that to the quench of .060"-converting this to cc's = 12.54cc & add this figure to your Cyl.Head's combustion chamber of 67cc = 79.54 (or 80cc final combustion chamber). Using the above final combustion chamber-you should obtain 10.5:1 Comp.Ratio (pushing the limits of pump gas). Now if you chose a 76cc cylinder head w/12.54cc Quench then you'ld get a 9.5:1 Comp.Ratio. For the 10.5:1 Comp.Ratio you'ld need a camshaft whose Intake Valve closed 54*Degrees ABDC. Whereas the the 9.5:1 Comp.Ratio would need an Intake Valve closing of 47*Degrees ABDC. BTW: the 47* or 54* requirements are the Seat to Seat (or opening to closing) figures-usually taken from the .006" opening on the cam bank to the .006" closing of the same cam bank figures. This is mostly speculative as I dont know the exacts of your piston top's. But I did configure my answers from the use of a 377 w/6"rods. So you should be close to your objective-dependent upon if you plan a race fuel engine only or a pump gas engine(?). BTW-no software...just a calculator/some things must be done the "Ole Fashion Way!" (haha) Kevin, (Yea,Still an Inliner) [ June 17, 2001: Message edited by: Kevin Shasteen ]

Your compression ratio depends on your Block Deck to Piston Deck Clearence. Did you have your block deck milled at all? Then again-there are multiple types of dome pistons-does your pitson dome top also have a relief in it? Or is the dome fully extended above the piston w/out the valve relief going below the piston top deck plain? If you were using flat tops-this would be your way of working the comp.ratio. As Pete illuded to-the books give an 11.1:1 to 11.2:1 Comp.Ratio for a .100 pop up. But what kind of Pop-Up is the question(?). If your block is factory stock-then your Quench w/factory length rods & factory piston comp.height w/flat top pistons would actually yield you a 10.1:1 Compr.Ratio. Figured like this: Your Quench, .022", which represents the Block to Piston Deck Clearence. Take that figure & convert it to cubic inches & then convert that to cc's. If you chose a head gasket w/.038" crushed thickness-you'ld do the same w/it-convert it to cubic inches & then convert that answer to cc's. Now take those two answers in cc's and add them together: you should get 12.54cc's. Add the 12.54cc's to your cylinder heads 64cc which yields 78.54: also add @ 2cc's for piston land volume. Now take the displacement of your engine 350 & divide by 8-this gives you 43.75 cu.in. per cylinder; convert that answer to cc's which yeilds 716.93. Now for the comp.ratio: 716.93 + 78.54/78.54 = 10.12:1 Comp.Ratio. The books lists a .100 dome as yielding an 11.2 Comp.Ratio w/64cc heads-as Pete mentioned above. To know for sure we would need to know what head gasket thickness, Dome type, Quench/Squish achieved after milling (if the block was milled at all). The unknowns are your block deck to piston clearence. Any milling of the block w/increase your compression. Kevin, (Yea,Still an Inliner) [ June 17, 2001: Message edited by: Kevin Shasteen ]

I have to agree w/all that's been said thus far-and then say it again/but in my own way. From what I've seen/read-the L28 (tho be it an inline 6) is actually a heavy duty built 6 & weighs more than you think it would. This is the reason you only gain about 150-160lbs when doing the JTR swap. When you put the numbers on paper of the weight savings by using alluminum parts that Pete mentioned/you get pretty close to stock spec's. And when you're that close to stock spec's-the amount of torque that a SBC or SBF can make at low RPM's-will far out weigh any torque that 3.0 (or it's cost) can put out. For $4400-you can get a rock solid/rip-snorten pavement pounding V8/Z...dont forget the brakes/suspension/tires to match the new found power! What's even better-is your mild/moderate street V8 will be by far more dependable than a tightly wound 3.0. Performance parts for an american push rod V8 are less expensive than hi/po go parts on the 3.0; so any repairs to the V8 set up (if/when needed) will be cheaper than when you break something on the 3.0. You may pay a little more up front on the V8 set up if you include brakes/suspension/tires-but in the long run there wont be the constant expense of repairing hi/po parts on the 3.0; put the pro's/con's on paper & then weight them against your total adjusted budget from 1-3 years -vs- power & performance gained. Then make your decision. BTW: if its 3.0 liters you want/why not go the Scottie GNZ route-use a Buick V6 & turbo charge it...great gas mileage & all the power you can afford. Or use a 4.3 V6/those V6's are known to be excellant little power houses...just some more things to think about! Kevin, (Yea,Still an Inliner) [ June 17, 2001: Message edited by: Kevin Shasteen ]

A good book on Windsors; both the 5.0 & the 5.8's is "Ford Windsor-Small Block Performance" by Isaac Martin published by HPBooks/Copywrite date 1999; & complimented by the book "5.0 Ford Dyno Tests" by Richard Holdener and published by SADesign/Copywrite date 2000. Nothing wrong w/those Fords-remember it took a Windsor & CarrollShelby to beat those Ferraris/not too shabby. Kevin, (Yea,Still an Inliner)

we here at Hybrid Z understand your justification to buy a forged crank & hereby grant such justification...as justified! Go for it; unless of course you dont wont to! I've read that cast cranks are good upto 600hp; but if I'm going that radical-I'ld just sleep better knowing I had a forged crank...it's your decision what you want. Kevin, (Yea,Still an Inliner)

Bank rolling a lightened crank is correct. If/when you lighten a crank-for the price you're paying for it you might as well throw in the knife edging to boot. All this lightening usually means molly weighted slugs in the counter weights...talking @ $3k easily. I also agree w/the earlier statement-in a Z where the car is anywhere from 600lbs to 1000lbs lighter than the cars that the 351W initially came in/the lighter weight is in the Z & doesnt arbitrarily need to be in the crank. BTW: the phrase "slow revving engine" is a relative one. In order for us to know what your friend was talking about-we'ld have to know where he obtained his information-other than that/its kind of useless to anyone. If your friend was talking about a Pro-Stock racer looking to maximize every little tid bit of power-then yea/maybe the crank does turn slow (compared to his other Pro-Stock racing buddies). However, dropping it in a Z; I'ld think a mild/moderate perf.build would light up the Z's tires! Kevin (Yea,Still an Inliner)

That's quite an intimidating looking engine. I'ld like to know what the charts in the upper left hand background say(?). Kevin, (Yea,Still an Inliner)

Mike, Those figures for Comp.Ratio's on your .030 flat tops are the piston mfg's suggestion for a slew of possible camshafts that would compliment said pistons. Since the piston mfg has no control over which cam an eng.rebuilder will be using then the [suggestions] are merely their [averaged] figures to determine Comp.Ratio's...now, if they were rebuilding the engine-then we'ld know their rules were followed and there'ld be no problem. You already said you're not sure of the camshaft currently in the engine-so this leaves us w/an unknown variable. The other side to this is we also dont know if your eng.block has been deck milled-so that also leaves us guessing as to the static comp.ratio (based on the Block Deck Height-being decreased if it were milled then this would increase comp.ratio). The next variable is-we dont know the piston comp.height of your piston; since you have the piston's part# you can call the tech line & obtain that info. Knowing the piston comp.height would also tell us what Connecting Rod Length your engine currently uses. Factory Piston Comp.Height = 1.560 for a 5.703" Con.Rod while a 6" Con.Rod would incorporate a Piston Comp.Height around 1.2something. These are the unknowns; your cam profile, piston comp.height & connecting rod lenhth along w/not knowing if your block has been decked. For my assumptions I'll consider your block to be factory stock, the piston comp.height factory stock & the con.rod also factory stock. 1.74" = 1/2 Stroke of the 3.48" 350 SBC 5.703" = Connecting Rod Ctr-to-Ctr +1.560" = Piston Comp.Height ------- =9.003" (This is called the Assembly Length) 9.025" Block Deck Height of 350 SBC -9.003" Asseembly Length ------- =.022" Block Deck to Piston Deck Clearence +.038" Head Gasket [Crushed] Thickness ------- =.060" Quench (or Squish) at TDC Take the Quench & convert it to Cubic Inches by the following: 4.03^2 x .060 x .7854 = .76533 cu.in; now take that figure & convert it to [cc's] by multiplying it by the convertion factor of 16.387 as follows: .76533 x 16.387 = 12.54cc's This 12.54cc's is what you'ld add to the Combustion Chamber [cc's] of whatever cyl.head's you choose. Inorder to determine what cc's Cylinder Head is required-we need to know when your Intake Valve closes ABDC (we need the .006" to .006" Intake Lobe Opening Bank Seat to Intake Closing Bank Seat figures); its actually the Intake Closting Bank Seat figure we'll be using. This will tell us how much Cylinder Volume remains in the cylinder after the piston has moved upward ABDC in relation to crankshaft rotation-in degrees. (The Intake Valve almost always closes ABDC-that is why we need that specific figure). So, not knowing what cam you have-I'll merely give you the average of what I came up with that you'll need. Based on your ideal comp.ratio you want. IC = Intake Closing. IC = 71*ABDC 53cc Cylinder Head Comb.Chamber +12.54 Quench in cc's ------- = 66cc Final Combustion Chamber cc's = 11.8:1 Static Compression Ratio *This requires Race Gas* IC = 62*ABDC 63cc Cylinder Head Comb.Chamber +12.54 Quench in cc's ------ = 76cc Final Combustion Chamber cc's = 10.4:1 Static Compression Ratio *Pushing the Pump Gas Limits* IC = 50*ABDC 70cc Cylinder Head Comb.Chamber +12.54 Quench in cc's ------- = 83cc Final Compression Chamber cc's = 9.6:1 Static Compression Ratio IC = 36*ABDC 76cc Cylinder Head Comb.Chamber +12.54 Quench in cc's ------- = 89cc Final Combustion Chamber cc's = 9.05:1 Static Compression Ratio If your shooting for a 350FWHP choosing a head w/an intake port of around 190cc-200cc should work out great for you. The issues you need to nail down are-Block Deck Height, Piston Comp.Height (which will tell you Con.Rod Length) and your camshaft closing rate (Seat to Seat-usually measured at .006" to .006"/intake lobe openine bank to the very same intake lobe closing bank). I really enjoy playing w/these numbers. I also really appreciate this site/because of your questions (now & past questions) I have forced myself to learn things I've never even considered; much less even knew exitsted! Kevin, (Yea,Still an Inliner) [ June 16, 2001: Message edited by: Kevin Shasteen ]

Andrew, What about additional heat; remember-you're in Michigan & ZFan is in Dallas; our Summers last a little longer than yours. Have you ran your car during the hotter days of your Summers; what was the heat build up-was it noticeable? I would definately want a Trans Cooler! Kevin, (Yea,Still an Inliner)

I thought the article spoke about actually being able to run the engine w/less timing advance due to the piston "Dwelling" at TDC for a longer time span-this allowed the timing to be altered...in a less radical manner. Yes/No(?). Any other ideas? Kevin, (Yea,Still an Inliner) [ June 14, 2001: Message edited by: Kevin Shasteen ]

Are you only doing a head swap or are you rebuilding your engine from the ground up? Your final compression depends on the pistons currently in your engine (dished or flat tops). If you're engine currently has flat tops (doubtful-they are probably dished if its a factory engine) & all you do is swap the heads-you're gonna end up somewhere in the 11.9:1 range. What you'ld need to run those 53cc heads is a 30cc dished piston; this would allow you to keep your 8.5:1 ratio. You'ld need 20cc dished pistons to reach the 9.5:1 comp.ratio. Chances are you have dished pistons-Find out from a local dealer which pistons were used in your engine (what their DISHcc's were) then we can have a better go at squaring away at what your final comp.ratio will be. Also-you need to be sure your camshaft is compatable w/the higher ratio. Just because you have a higher ratio doesnt mean your engine will improve-if your cam is too mild/you'll run out of power before the comp.ratio has a chance to really kick in. Remember: Dynamic Comp.Ratio (While the engine is running) and Static Comp.Ratio (while the engine is not running/not moving) are not one in the same. You'll definately feel a boost by putting those 53cc heads compared to what you have now, however-if you dont replace your cam to match the heads/your engine will run out of high RPM HP before the engine actually reaches its peak potential; which those heads are designed to reach. The 305 & 350 have the same con.rod/piston conpression height-so they should swap, but I'ld wanna talk to a local machinest knowledgeable about making such a swap before buying those heads-ask about all clearance issues. Hope that didnt sound like a bunch of circular double speak? Kevin, (Yea,Still an Inliner) [ June 14, 2001: Message edited by: Kevin Shasteen ]

Everything I've read about Detonation indicates that Swirl, [(Quench & Squish)sometimes considered the same thing] combined w/an appropriate compression determine detonation. The sources I've read claim that an engine's Quench has the most effect/non-effect on detonation; anything over .060" Quench & your pushing for disaster-even at a 9.5:1. Most SBC's piston deck clearence are usually at .022" in a SBC, plus the .038" gasket crush thickness ant you're at .060" already-when the piston is lowering itself in the cylinder-the pressures are decreasing & this phenomenon combined w/a High Quench clearence causes determines. I've read where even turbo engines can benefit from a .010" Piston Deck Clearence-keeping the compression the same by altereing the piston/dishcc's. This would allow the piston to maintain its Quench/Squish for a longer period of time. By Deck Milling the engine to near "0" piston deck clearences to maintain better Quench...you're fooling the engine/this is basically the same thing you're doing by increasing the Rod Length-your are increasing the Dwell time of the piston during its Quench/Squish: Better Effieciency/less loss of cyl.pressure = more power. I'm not sure about the wear factor-jury is still out on that one. Kevin, (Yea,Still an Inliner)

Okay, class; should I tell Lone that I was reading the book as I gave the description of the pointiac blocks or just keep on allowing him to be in awe of me? Shhh-keep this a secret! Lone; I did remember that the Pointiac's intake was seperate-& didnt see the picture of it till I found my book. Then I found the section on the description of the block. (Man I hate busting a guys bubble of me-I'ld rather do so after I conned him out of $20.) Hey Lone; can I borrow $20? Kevin, (Yea,Still an Inliner)

Jim, That very "Idea" can be determined on paper thru formulas. Both the amount Displacement air and the amount of Ram Air thru the Outer Air Intake. A few Auto Math books I have talk about the very subject: I'm not an expert so I'll attempt to paraphrase it intelligently as I can. I)Gas Velocity Thru Pipes/Ports Example: Free Breathing 350 V8 running at WOT @ 6500rpms using a carb w/4 identical venturis, each of 1 11/16" diameter w/VE = 85%. What is the gas velocity thru each venturi? The author suggest not envisioning air as one long continuous "string" but more of a slug of air "a cylinder of air"..as this makes it easier to mentally digest. The author claims theoretically every 4stroke engine inhales a volume of air equal to half its displacement w/every revolution: 1/2 of 350 = 175. 175 x 6500rpms x .85% = 966,875 cu.in/minute = @ 560cu.ft. (1cu.ft = 1,728 cu.in) 4 Venturis; each identical & handling 1/4th the total; 560/4 = 140cu.ft./min Next you have to determine the cross sectional area of the venturi: 1 11/16 = 1.69 A = .7854(D) A = .7854 x 1.69 A = 1.327 sq.in or @ .0092 sq.ft (where 1sq.ft. = 144sq.in) Remember we're dealing w/a slug of air; we now need to determine what the size of that slug is-as we know its volume to be 140cu.ft. All we need is to know its length. V of Cylinder = A x H H = V/A L = 140/.0092 L = 15,217 ft So, the rate of flow is 15,217ft/min which is 253ft/sec which is about 173mph! Now, the subject of Inertial Ramming's effect on engine output at high speeds (Air Intake-AKA: Hood Scoop of some design) Even tho the air is still & the car is moving-its obvious (to us anyway) that one can reverse the role & envision the car standing still & the air moving-this is why the ducts on hoods face forward: this ram effect is called "Velocity Pressure" sometimes also called "Velocity Head". The example given is for a vehicle at 100mph; the books reminds us that air weighs .076 lbs/cubic ft at atmospheric pressure of 14.7psi. The formula is: Pvel = P*V^2/4311 where: Pvel = Velocity pressure, psi p = air density, lb/cu.ft. V = car velocity, mph Pvel = .076*100^2/4311 Pvel = .18 psi The book claims this "less than 1%" increase in power output is minimal due to the air's entry into the engine: which is always at right angles in direction of travel, and certain amount of energy is lost due to the needed 90* bends in the plumbing. The fraction of recovery actually obtained (called the Pressure Velocity) can be as high as 97%; it can be as slight at 13% dependent upon it's angle of entry. Even w/the best design its rare that 90% is obtained. It goes on to say that the Velocity Recovery is dependent upon the "square of the speed". So at a higher rate of speed-the results increase as well. The next example given was a race car @ 180 mph w/Velocity Recovery of 90%. (The .9 in the formula represents the Velocity Recovery) Pvel = .076*180^2*.9/4311 Pvel = .5 psi Power Increase of about: 14.7 + .5/14.7 = 15.2/14.7 = 1.034 (@ 3%) Power Increase = 3%; now if you've had the engine dyno'd then you'll know its torque/hp output at that rpm. You can then multiply its .3% x Torque & HP for its actual increase in power. I thought it was pretty interesting! Kevin (Yea,Still an Inliner-W/a very low Velocity Recovery %) [ June 13, 2001: Message edited by: Kevin Shasteen ]

If I remember correctly-the Pontiac's intake manifold's #1 & #2 intake ports were connected to each other (like a crossover almost) and there was actually an air gap between them & the intake manifold backwards? The thermostat sat on top of the #1 & #2's crossover port! I hope I explained that intelligently enough; the gap is such that you can actully put your hand between the two ports & touch the valley pan (Does memory serve me correct-that would make the Pontiac's a 2-piece intake manifold?) If its a Pontiac Block (Per American V8 Engine Data Book) the Pontiac Div have used two basic blocks thru the years. The simplest way to ID a Pontiac block is to count the freeze plugs on each side of the block or you can count the "sets" of side motor mount holes. If there are no side motor mount holes then it is a 55-58 vintage block. If there are only two side motor mount holes it is a 59-66 vintage block. If there are three side motor mount holes or five side motor mount holes then it is a 70 & later block. What separates the 59-70& on blocks is the number of freeze plugs in the side of the blocks. If it only has two freeze plugs on each side then it is a 66 or earlier block. If the block has three freeze plugs on each side then it is a 67 or later block. Kevin, (Yea,Still an Inliner) [ June 13, 2001: Message edited by: Kevin Shasteen ]

Nice fit/good look. The shop looks like someone's been very busy having a lot of fun putting a very serious car together (dont let it bither you). Whenever I get a chance to do major upgrades on a car; I always like to cut the companies emblem (icon) from their packaging box of each performance item I've purchased. Then I can either rubberband them together to never be seed again or put them in a picture frame & hang them somewhere; kind of neat/makes me feel important anyway-and in this "Politiacally Correct" world...its good to "Feel"...isnt it? When's your ETA for Launching your land missle? If you're at/past the point of ordering wheels/tires...you must be getting close! Kevin, (Yea,Still an Inliner)

Mike, I was wondering about your current engine/stroke, comp, rear gears-that you're actually set up for drag racing..the comp.ratio you could live w/if the stroke were less. Have you had a chance to look at the book I was talking about-it has a great explanation on how to find CG; fore/aft & from side to side...I dont know what it was called before it was re-written I only know what it is called now "Mustang Performance-Handbook 2" & by William R. Mathis. By their explanation-CG seems pretty easy to find; also making one of their jigs for determining weight of the car at each wheel seems pretty easy (as resourceful as you are) I bet you could make one in a 2/3 hours; check the book out! Kevin, (Yea,Still an Inliner) [ June 12, 2001: Message edited by: Kevin Shasteen ]

Nother Brain-storm; it hit me (finally)-Hey, I have access to the net! Why not do a search on Cd's (I must be an out of work Rocket Scientist). Anyway, this is what I found. Cd's of current cars: 1) Cd = .195 GM's EV1 Electric Car 2) Cd = .199 Ford's Prodigy (Hybrid Electric) 3) Cd = .25 Honda's Insight (Hybrid Electric) 4) Cd = .25 Lexus's LS 430 (lowest of all Sedans 5) Cd = .27 VW's Passat 6) Cd = .28 Lexus's IS 300 7) Cd = .29 C5 Corvette Coupe 8) Cd = .29 Mitsubishi Gallant 9) Cd = .29 SAAB's 9-5 Aero 10) Cd = .32 Toyota's Celica (Latest Design) 11) Cd = .33 Ferrari's 360 Modena (after 5600 hours of Wind Tunnel Testing) 12) Cd = .34 Ferrari's 355 13) Cd = .37 Ford's 94/95 Mustangs 14) Cd = .38 Dodge's Viper GTS (Down from .50) 15) Cd = .41 Ford's Late 80's/Early 90's Mustangs I think the decision, on an earlier post on this thread, to go w/Cd of .31 to .34 on Mike's car was an appropriate one. I had no idea till I researched it that the initial Vipers had a Cd of .50(?)! That's incredible..I remember reading about the car in early tests; I remember the driver talking about the car shaking violently as he approached top speeds....now we know why. It was hitting a brick wall of air. Just for fun-lets use Mike's point about a sub 500hp Viper to see what its max mph speed should be (the Viper Site I found listed the Viper's height = 48.35 & width = 76.18 w/a Cd = .38; this gives us a frontal Area = 38.68 & lets say the Viper's peak 500hp/6000rpms attempting to hit max speed-what is its max speed? V^3 = ((500 x 15 x 10^4)/(.38 x 38.68)) V^3 = 5102596.201 V = Cube Root(5102596.201 V = 172mph Look out everyone-I've got a new toy to play with (areodynamics); too too cool! That Viper site also listed the GTS Viper w/3.07 rear gears & 27.5" rear tire. This would put the above theoretical 172mph at: 1) 6451rpms in 5th gear 2) 3225rpms in 6th gear Kevin, (Yea,Still an Inliner) PS: Mike-What I dont understand or have the knowledge to offer; is what torque is needed at high speeds to reach a 200mph objective? Have you considered your rear gear possibly being too steep for a road rally car in relation to your engine's torque/hp characteristics? [ June 12, 2001: Message edited by: Kevin Shasteen ]

Okay Mike-this is what I've learned after a nights worth of reading on Areodynamics (jury is still out on some of it). The issues are: 1) Areodynamic Drag at High Speed 2) Induced Downforce (tail wing?) 3) Lift/Drag Ratio 4) Absorbed HP as a result of drag The areas where we'll have to concede are that we dont have a dyno print out of your car therefore we dont have actual #'s for each 200rpm increase for torque/hp; nor, do we know what your Coefficient of Drag "Cd" is..so we'll have to guess in those areas. What we can/do know is the frontal area of your car (you take the measurements); we know what your car did in the 1/4 mile from an earlier posting on HybridZ-this will give us hp/torque at that specific MPH/RPM, we know what MPH you'ld like to reach and we know the gearing. After reading all that I did last night-I agree w/Hennessey's sumation-your Areodynamics are gonna be extremely important. Here's what I've come learned: One book I have gives these Cd's (Coefficient of Drag) numbers: 1)1.2 = Cd for A barn door "as a reference" 2) .44 = Cd for a VW Beatle 3) .35 to .45 = Cd for a Typical Modern Sedan 4) .31 = Cd for a Winston Cup Car a few years ago *NOTE: I think its safe to assume your car's Cd is somewhere between .31 & .35 The formula for Drag"hp" absorbed is: Where: Drag"hp" = HP absorbed due to drag Cd = Coefficient of Drag A = Frontal Area in Sq.Ft. V = Velocity, mph Drag"hp" = ((Cd x A x V^3)/(15 x 10^4)) This book also explained how to figure "A" frontal area for Areodynamic formula: take .80% of the height of your car from the front view (as if you're looking at your car while standing in front of it) & multiply that times the width of the car's frontal view. I dont know your car's frontal area since you've changed front end clips; but I measured my 78Z 2+2 & it measured 49"H x 60"W; so .80% x 49"= 39.2" & remember we need sq.ft. not sq.in. so we have to convert our measurements like this: 39.2 x 60/144 & this gives us 16.3 sq.ft. Frontal Area. Take the formula for Drag using Cd of .31: Drag"hp"= ((.31 x 16.3 x 200^3)/(15 x 10^4)) Drag"hp"= 40424000/150000 Drag"hp"= 269.49hp That's an awful lot of hp loss due to drag. There was another formula the book gave to determine what peak "MPH" would be using the same numbers above; in this formula you have to transpose #'s w/in the formula-it is as follows: BTW-I'm using your 469RWHP from your 1/4 ET=128mph at 5683rpms (rounded to 6000rpms). Where Khp = Known RWHP Khp = ((Cd x A x V^3)/(15 x 10^4))*Drag"hp" remember to transpose (multiply both sides by 15x10^4) ((469hp x 15 x 10^4 = .31 x 16.3 x 200^3) Transposing still (swap sides to get V^3 on the left side) V^3 = ((469hp x 15 x 10^4)/(.031 x 16.3)) Tranposing still (divide both sides by .31 x 16.3) V^3 = 13922422.32 V = Cube Root(13,922,422.32) V = 240 (theoretical mph) *NOTE=Remember I used the Cd equivalent to a Winston Cup car; now lets go w/the Cd of .34 (just under the Cd of a modern Sedan. If we used a Cd of .34 this would give us a top MPH speed of 233mph. So using the Cd's of .31 & .34 we find a top MPH speed of: 1) Cd .31 = Top MPH/240 2) Cd .34 = Top MPH/233 This all falls on assumption of your Cd & if you have the torque at the appropriate rpm's. The driveshaft torque at your 1/4mile ET based on your 1/4mile HP of 469hp is: Torque = 5252 x HP/RPM Torque = 5252 x 469/6000 Torque = 410ft.lbs Your T56's 6th gear is .5ratio; multiply the ratio times the 410ft.lbs (assuming a .90VE) gives us: 410/.90VE = 456ft.lbs*.5 = 228ft.lbs of torque being applied at the rear wheels at 6000rpms...you only need 4844rpms to reach 200mph; so the variables, actual torque, actual hp & actual Cd are going to determine you reaching your objective. (Well Duh!) What kind of rear wing are you running (Length x Width); Remember that any -Lift (Negative Lift) will aid traction & reduce drag which will aid in your top mph speed; upto a certain point (I cant believe I just said that-it actually sounds half way intelligent/My head hurts) Whooo; boy that was a mouthful-but I enjoyed every bit of it. Kevin (Yea,Still an Inliner) [ June 12, 2001: Message edited by: Kevin Shasteen ]

Coefficients of Drag -vs- MPH, Center of Gravity-fore/aft or from side/side??? I've always avoided those chapters when reading. I do have some books that talk about it-but I've never really read up on it as its not as exciting as HP/Torque, ET's Arrg Arrg Arrrg-Ohh ohh..oh yea (Tim Allen Impression on the Internet). Mike, there's a book I have that deals w/how to set up your car for performance handling: specifically SCCA & IMSA. Its a Ford Mustang book but it is chock full of info-you might want to check it out the next time you're near a Barnes & Noble. The name of the book is "Mustang Performance-Handbook 2" by William R. Mathis; its an HPBook & its copywrite is 1995. If you look for it-its binder is white & the title is in bright Red/has a lot of good info in it. In it they have diagrams on how to check center of gravity, side to side center of gravity & have diagrams on how to build a jig which allows you to use home scales. Another book I have on Auto Math talks about center of gravity & weight shifting during road racing-it says for a road racer you'll want a slight rearward weight bias as this favors better traction & thrust & claims that side to side weight distribution should be "even" for consistent cornering in either direction (which means adapting your cars weight w/the weight of the driver). About Coefficient of Drag...I'm gonna have to read up on that one. Kevin, (Yea,Still an Inliner)

I remember reading some report on the Viper when they first came out; the driver was attempting to hit the 200mph max...some mild perf.mod's had been done. I dont actually remember the outcome (its been too long ago) but what I do remember is that the Viper actually lost "MPH" speed when they shifted to 6th gear due to the drag at high speed; had to downshift back to 5th to get his speed up! What does all this mean...Ownt Know(?)! Just thought I'ld throw it out at ya just to be aware of drag & the importance of overcoming it. Got my fingers crossed as I'm sure everyone on this board does; hoping Mike hits his objective! Good Luck Dudeman! Kevin, (Yea,Still an Inliner)

I deny all wrong doings/knowledge & refute all allegations of my wherabouts as to the appropriate answer to your questions. "Havent gotta a clue"! Kevin, (Yea,Still an Inliner) PS: The only dumb question is the one not asked...I'm sure someone has the answer-its just a matter of them logging in & reading your question/Timing is Everything!

Mike, Ready for the new numbers? I confirmed the trans gears from my "Camaro Bolt on Perf.Guide" Copywrite date 1999-should be current (hope Lone lets me get by w/these numbers; haha). 1994+ T-56 1st = 2.66 2nd = 1.78 3rd = 1.30 x 3.7 = 4.81 @ 6k = 95.26mph 4th = 1.00 x 3.7 = 3.70 @ 6k = 124.27mph 5th = .74 x 3.7 = 2.74 @ 6k = 167.94mph 6th = .5 x 3.7 = 1.85 @ 6k = 248.55mph *NOTE: In 6th gear you only need 4850rpm's to reach your 200mph goal w/your 25.77" tires. Good Luck & Hope you reach your objective! Remember to confirm what your cyl'head's intake port opening area (sqare inches) are-this will help you confirm which camshaft is best for your chosen compression. Remember, the area you need to measure is not the immedieat opening-but just inside the port opening exactly adjacent to where the push rods are coming thru the heads-as this is where the cyl.head's biggest restriction is & its that restriction that determines what your cyl.head's peak power (airflow) will be. Mike; have you thought about mounting a Cam Corder in your car somehow, so you can catch all the action during your racing? Kevin, (Yea,Still an Inliner) [ June 10, 2001: Message edited by: Kevin Shasteen ]

RACNOTH/RACNOTH/RACNOTH!!! I hate to admit it but I made a mistake in your HP needs; the formula was for RWHP-so that required 165HP at an .85% Volumetric Efficiency is actually a 195 FWHP!!! Sorry for the confusion...I hate it when I do that...there are just so many numbers to crunch sometimes I forget which ones I'm crunching at times. Again; your required hp is 195 FWHP which is the same thing as 165 RWHP if your engine is running w/an 85% Volumetric Efficiency! Hope I didnt cause too much confusion. Kevin, (Yea,Still an Inliner)