vega

very cool

Here is the formula to calculate the size the smallest cross section in the cylinder head should be. .00353 X bore X bore X stroke X rpm/ 690 = cross section in sq" Rpm= rpm you want max. horsepower 690= 60% of the speed of sound Here is a calculation: .00353 X 4.03 X 4.03 X 3.25 X 6800rpm = 1267 1267/690 = 1.836 sq"

The head options I am looking at (1 having the highest numbers on the bench); 1 AFR 195 Eliminator 2 Jegs 195 3 AFR 180 Eliminator 4 Trickflow twisted 190 5 Jegs 180 6 AFR street 190 7 AFR street 180 I have a range of either a 180, a 190, or 195 The highest flowing head under 180 is the Edelbrock RPM 170 head That seems too small to me.

I already have the cam that is optimal and i am stuck between two weiand manifolds.

OZconnection I read your stuff. We already know that smaller ports creat more tq at lower rpm. we also already know that bigger ports will create more hp at high rpm sacrificing tq at low rpm. I am looking for something in the middle of this. My operating range is all the way down from 1500rpm all the way to 68 or 69000rpm that is a WIDE RANGE. so what would the best cc port be then to achieve the flattest tq and hp curve be?

info from another page "It is possible to calculate the areas fairly well. You must know at what rpm your your camshaft will give peak power rpm. The formula I use looks like this: ( cc of 1 cyl. X RPM X VE ) / ( 3000 X m/sec. ) = area in mm squared. The velocity at the csa is 140 m/sec. and at the port entrance around 106 m/sec. The entrance area depends on where the CSA ends up, how long the intake runner is and how much of it is in the head. It should of course not be bigger than the carb or throttle body. Sportbikes have very large entrances in the head with calculated velocities around 70 m/sec. On a 4 valve head the csa is just before the valve guide on a downdraft head and just before the bend on a more horizontal head." Does this seem right?

One of the rods and pistons with cap http://i938.photobucket.com/albums/ad226/faytmorgan/rodandpistonwithcap.jpg One of the pistons close up http://i938.photobucket.com/albums/ad226/faytmorgan/40overpiston.jpg Bottom end http://i938.photobucket.com/albums/ad226/faytmorgan/327bottomend.jpg Top of piston http://i938.photobucket.com/albums/ad226/faytmorgan/topofpistoninmotor.jpg The cylinder wall scoring I was talking about that I may have to sleeve :/ http://i938.photobucket.com/albums/ad226/faytmorgan/cylinderwallscoring.jpg I was stuck (going back through my paper work of cam comparisons) between two cams. 12-673-4 http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=232&sb=0 or 12-678-4 http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=227&sb=0 The 12-673-4 cam is not as high a lift is in the same operating range if not a little better than the 12-678-4 cam so I honestly don't really see why I did not decide to go with the 673 cam. Either way- the motor is already 40 over may have to 50 over or a sleeve for one the cylinder walls has a small groove. The crank is forged - I am staying with that crank (3.25 small journal crank). I don't need to stay with my flat tops I don't know the specs on them other than they were are 40 over. I am looking to have 10:1 to 10.5:1 compression so whatever I needed to get there with my bore and stroke etc. I have also considered 6 inch rods over 5.7 - although I don't know if it will make a huge difference asides what piston I go with. 2800 pound car 3.545 rear ratio .7 forth gear 184mph at 6000rpm in 4th gear aerodynamics forgiving 4.040 bore 3.25 stroke flat top pistons Intake http://www.jegs.com/i/Weiand/925/7547-1/10002/-1 Rockers http://www.jegs.com/i/Harland+Sharp/851/1001/10002/-1 1500-6500 operating range (power range) 6800rpm red line shifting at 6000 to 6500 rpm I do not know the combustion chambers or the intake runners or the piston deck height. I am not sure how to find this. ----------- Lastly this is the email I received from my cousin (currently going to college for this kind of stuff) I figured I would ask him for the math at least. He is far from hands on and knows more about engine theory than building one. "This is an interesting topic. I wish I had more time to help you dive into the specific calculations for your engine. But here are some considerations. First of all, when the article mentions air being thick and heavy they are referring to the intrinsic properties of air. Even perfectly clean air has a nonzero viscosity and a nonzero density. Viscosity (or stickiness) is a measure of how hard it is to rapidly deform or shear a pocket of air. Density is the mass of air per unit volume and is thus directly related to how hard it is to accelerate. During our everyday experience with air we seldom have to quickly accelerate much of it or force it through confined areas. So we dont experience its stubbornness and naturally think of it as being light and free moving. But within an intake port, the stickiness and heaviness of air become very important. The air is required to fill the volume displaced by a cylinder in like 10 milleseconds which means the air is required to travel at up to several hundred mph through a restriction the size of a penny. Try inhaling as fast as you can with you mouth wide open. Then try inhaling as fast as you can with a straw in your mouth. The second way is noticeably harder and prevents your from inhaling as quickly. This is basically the same phenomenon that robs the performance of an engine. Your mention of wide versus narrow ports has to do with inertial ram which is an important and relatively simple phenomena this article seems to gloss over. If you have somewhat long intake pipes, the column of air within the intake pipe gains appreciable momentum as it rushes toward the cylinder. Because of its momentum, toward the end of the intake stroke when the cylinder is nearly full of fresh charge, this column of air tends to keep moving and forces itself into the already "full" cylinder. This is analogous to turbocharging where additional air is pumped into the cylinder by a turbine. If you didn't have intake pipes and your intake valves opened str8 into the throttle body chamber this inertial ram effect would not occur. In this case you would always want the biggest possible port diameter since restriction would be the only possible issue. But intake pipes are used because of the inertial ram effect even though they offer additional restriction. Narrow intake pipes tend to work better because of higher velocity and hence greater momentum of the air column. But unfortunately there is a trade off because as you say, at high enough speed, the narrow pipes offer too much restriction for the higher airflow. I like to call it the coffee straw effect. Its a matter of what rpm range you plan on running the engine. You can't get optimum performance over the entire range you quote. This aspect is closely related to intake valve timing. To take advantage of inertial ram the intake timing needs to be sufficiently delayed so the intake valve stays open past when the cylinder would normally be "full" at BDC. You have to be very careful which velocity you are dealing with. To achieve increased airflow through inertial ram you want the velocity along the length of the intake pipe to be high which means narrowing it. You never want to further increase the velocity across just the valve seat by limiting valve lift. I dont see what this buys you. Its just increases the overall restriction. Its not very convenient to think of torque in terms of either of these velocities. Your glossing over the big picture. Its simpler than that. Torque depends solely on how much air-fuel mixture you can get into the cylinder and burn. So you do whats necessary to get maximum air into the cylinder. And the higher the speed at which you can achieve good airflow, and hence good torque, the better the power. Remember power is rotational speed times torque. If you ultimately care about power, **** low end torque and go for the wide intake pipes so you can achieve inertial ram and minimal restriction at high speeds. In my opinion, the best way is to tune your engine for maximum power. If you want the vehicle to lurch forward from a standstill, that can always be done through a transmission. So many sluggish vehicles are on the road because people have had suffered from obsession with low-end torque. The article overemphasis the importance of wave dynamics. Yes, by taking advantage of what is sometimes referred to as the organ pipe effect, you can slightly boost your performance. But it can be very cumbersome to deal with and maybe not worth it unless you have everything else perfect. This is mainly because each calculation is only valid for one particular speed so you can boost performance at only very specific speeds. For example, with a certain design you may have a noticable boost between like 2100 and 2200 rpm and then again between like 4500 and 4700 or something. If you've ever driven a vehicle where stepping on the throttle at certain speeds gives great power but stepping on the throttle at other speeds is quite sluggish, this is most likely what's happening. Often designs that take advantage of this effect have different length intake pipes (aka runners) for each cylinder. This ensures that each cylinder gets a boost at different speed. The overall effect is to smooth out the power delivery so engine gives more consistent performance across a range of speeds. GM's quad 4 for example used this principle which I'm guessing you see a lot of. And they are quite powerful engines for their size and cost. Yeah direct injection is where the fuel is directly sprayed into the combustion chamber. The detrimental effect of fuel in the intake port is there (otherwise no point of DI) but its a rather unimportant second order effect. Remember that air-fuel ratio is about 15:1. So the mass of fuel involved is less than 10% of the air mass. An engine is basically an air pump. In fact, quite accurate computer simulations of intake performance can be achieved without even considering fuel. As they say, the smoothness of the port wall is not very important unless its terribly rough. The air molecules next to the port wall are necessary stationary regardless of the wall texture or material. So, the only molecules that are going to see the surface protrusions are those already stopped near the wall. " Anything else?

I would still hope to find better pictures than that.

Yeah pretty much ha, I don't know what's going on with that dude's shirt... or lack of it. I definitely would like to see some more normal pictures ha ha, but around those lines.

http://en.wikipedia.org/wiki/Cylinder_head_porting I have been doing some further reading and research on different parts of the intake systems of the 4 stroke engine. There are three things I am struggling with when it comes to this article, AND what "everyone has been telling me". MY MAIN CONCERN is the fuel/air velocity calculation. "The "Porting and Polishing" myth It is popularly held that enlarging the ports to the maximum possible size and applying a mirror finish is what porting is. However that is not so. Some ports may be enlarged to their maximum possible size (in keeping with the highest level of aerodynamic efficiency) but those engines are highly developed very high speed units where the actual size of the ports has become a restriction. Larger ports flow more fuel/air at higher RPM's but sacrifice torque at lower RPM's due to lower fuel/air velocity. A mirror finish of the port does not provide the increase that intuition suggests." So how does one find a medium port flow cc on for the intake port on a head for a mean of what would be best for high rpm and what would be best for low rpm and whatever the middle is for engine "x"? Also reading this same article it talks about efficiency of air flowing through the intake being heavy almost a thick liquid making it difficult for the engine to pump. Is there a way to filter it down (...yes i know what an air filter is but this seems to be a bit different than that)? To filter it down so it is not longer thick for the lack of better terms? It also talks about fuel coming in the same port and how this affects the air coming in the intake (to me it sounds pretty much negatively). So, why don't we have a separate port entirely JUST for fuel until it reach the exact point where the air fuel has to be mixed before it reaches the cylinder? Or is this what direct injection is? http://www.engineeringtoolbox.com/ductwork-equations-d_883.html This also shows a "way" to calculate velocity. Albeit how much is needed for particular applications eludes me. For example low velocity seems to build Peak power but loses tq at bottom end (no one person or article i have found counters this) and with high velocity seems to build more power at lower rpm. Well to get a higher velocity one needs to close (make smaller) the the intake port (on the cyl head), but by how much? If one continues to close it (perhaps too far) air won't be able to get through it efficiently. Something that adds to the dilemma in my opinion. Any insight would be grand! Vega-

I know some of you older gentlemen have got to have some old photos of you with your old 78 and older z car from back in the 70s (black and white color doesn't matter). I thought it would be really "cool" to see these pictures posted up. I am having a hard time find old pictures like that of the car and the person back in the day when it comes to the old z. Here is a great example of what I am talking about- but not a z car unfortunately. http://www.hotrodders.com/forum/attachment.php?attachmentid=61025

I am just curious of the ones that I posted links to which look like they may be the best fit - or the ones with the least mods to make fit. a couple of them look as if they go above the engine. which is something I do not want, if they do it would be fairly difficult to plum the rest of the piping. I think I have been drinking to much because I just had an inappropriate comment for the pluming of the piping that I had to delete...

anyone have any ideas?

So I take it no one has tried to make them fit yet? well its a good thing i have a hoist at work I can use to try fitting them. and they are cheap. crossover type http://www.summitracing.com/parts/SCH-H179V/?rtype=10 http://www.speedwaymotors.com/Garage-Sale-Speedway-S-B-Chevy-Spread-Port-Headers,31830.html?sc=WGB&utm_source=GoogleBase&utm_medium=feed&utm_campaign=GoogleBase http://pitstopusa.com/i-5056730-schoenfeld-asphalt-late-model-180-crossover-headers-1-3-4-tube-diameter-3-1-2-diameter-x-9-collector-standard-sb-chevy.html http://pitstopusa.com/i-5056670-schoenfeld-asphalt-late-model-180-crossover-headers-1-3-4-to-1-7-8-to-2-tube-diameter-3-1-2-diameter-x-9-collector-spread-bore-sb-chevy.html http://pitstopusa.com/i-5056666-schoenfeld-asphalt-late-model-180-crossover-headers-1-5-8-to-1-3-4-tube-diameter-3-1-2-diameter-x-9-collector-standard-sb-chevy.html http://pitstopusa.com/i-5056669-schoenfeld-asphalt-late-model-180-crossover-headers-1-3-4-to-1-7-8-to-2-tube-diameter-3-1-2-diameter-x-9-collector-standard-sb-chevy.html http://pitstopusa.com/i-5056670-schoenfeld-asphalt-late-model-180-crossover-headers-1-3-4-to-1-7-8-to-2-tube-diameter-3-1-2-diameter-x-9-collector-spread-bore-sb-chevy.html I'm not sure which of the many choices I have would be best to start with (the motor is a marine block 327 btw.

Will 180 degree headers for a sbc (on a sbc swap) fit in the s180? or is there some kind of extensive mods to make them work etc? does anyone know any info on using these headers? I honestly think they just sound very amazing and would like to use them in my swap if i can.

So from advice from a people here and other venues, as well as a ton of reading it looks like for my setup the l98 heads are the best choice. My deal now is that I am having a difficult time distinguishing the differences in the many types of L98 heads. ---------------------------- there was; On the firebirds/camaros iron 305 heads from 85-86 iron 305 heads from 86-89 iron 350 heads from 87-89 iron 350 heads from 90-92 on the corvette iron 350 heads from 84-86 aluminum 350 heads from 87-89 Aluminum 350 heads from 90-92 ----------------------------- This gives me waaay to many choices. This is for an 86 camaro intake and I am unclear if I can use the 87 and newer style heads for one, and to be blunt what they all flow like and their valve size and combustion chamber size. Can someone shed some light on these for me?

http://support.moates.net/2009/05/07/gm-86-95-obd1-guide-read-me/#comments <- the tuning software I am using. How is it that you say the TPI system is low rpm? because the intake? I am having it port matched/extruded, edelbrock runners, etc. Looks like the l98 heads (which btw there are a lot of choices... no wonder why gm is bankrupt) are the best choice from a ton of reading and advice from a lot of people.

I will be tuning the ecu with a moates ostrich.

some teasers; http://i938.photobucket.com/albums/ad226/faytmorgan/tuneport2.jpg http://i938.photobucket.com/albums/ad226/faytmorgan/tuneport1.jpg

very small budget, but carefully bought parts cheaply. the only 80s vette tune port heads that will work are the ones from 85-86 the intake changed in 87 and is a pita to work with. Basically what cc chamber am I looking for to keep the compression down to 9:1? And of the heads that are of that chamber size what is the best to go with as far as flow goes? If there are heads that can be ported that is an option for me too. I also need to keep it a 194 valve because - again its a 283. As for the car this is going into, that is on the d.l. right now. As soon as it goes in the car (which should be shortly after this is figured out and parts are received) I will make a build thread of the entire car from scratch.

I picked up a 86 camaro iroc - intake, engine harness, ecu, injectors, and sensors for 150 bucks. 283 block 283 forged crank, 283 forged rods pistons have not been chosen because I have not chosen the heads yet. I need to run a 194 x 150 valve the heads need to work with that intake running the lunati 401A3LUN cam http://www.lunatipower.com/Product.aspx?id=1966&gid=284 I need to be at no more than a 9:1 compression ratio I know the 305 tpi heads are something like 58cc and the 350 tpi heads are 64cc (but from my understanding the 87-89 aforementioned 350 tpi heads wont work with that intake?). I have no idea what that will give my 283 for compression. help would be great! I need to know what my best choice for heads are so i can pick up pistons.

I thought it was the same bumper as they have on the type 1 kit- I have been searching for about 2 hours now (couldn't sleep) 31 pages on google images no videos of anything. Everyone seems like they want the type 2 or 3 kits which are just too new looking for my taste. But I want a urethane kit not fiberglass. I wanted to make sure if it was the same as the type 1 kit so I can just trade out the fiberglass one for the urethane one. Does that make sense? http://www.thezstore.com/page/TZS/PROD/7RS/50-1470 type 1 rear skirt fiberglass

Looking to buy a rear bumper from the z store, I can't find any better pictures of this bumper on other z cars. Does anyone have any pictures of this bumper on their car or some other person's car? part number 50-1650 http://www.thezstore.com/page/TZS/PROD/7RS/50-1650 Thanks in advance as always. Vega-

[quote name=Supra510' t imestamp='1302809366' post='933387] ^^^^^ Is everything you need to know. Deja mentions pushing the wheel past 0 offset which is true. While it does affect scrub radius, it doesn't affect physically fitting the wheel on the car. As he noted, if you're running a 9 inch wide wheel (which btw is 10 inches wide if you measure edge to edge) with a +24 offset the backspacing is 6 inches. Since there is only 4.5 inches of available backspacing on the car, your wheel will smack the strut. So, you buy the 1.5 inch adapter and it spaces the wheel out away from the strut the appropriate amount. Here's another calculator that's more visual http://www.rimsntires.com/specs.jsp 1 what is scrub radius? Thing 2 so all I need is the 1.5 inch adaptor for this to work? (aside from the fact that I will either need to roll fenders or cut- I am still doing body work so I want to do this now to know where I need to do what)

Well the factory z is zero offset and I want to be able to use a 24 without smacking the suspension. Honestly it feels like you guys are being vague, I know your trying to help me, but I just don't get it or something, I feel like there is something I am missing. The suspension and wheel stuff has always got me a bit. Give me sensors, electronics, brakes, engine overhaul, I get it. Suspension (ie camber caster toe and this wheel stuff) has always not quite clicked for me.