LOL. I would hardly call that a typical small block Chevy.
8.5" deck height 4.125" bore 2.8" stroke
It has 2 160 lb/hr injectors for each cylinder, and at peak the turbo can push upwards of 50 PSI through. Everything about that engine is custom. The block is a custom from Dart. The heads are Dart Lil Chiefs, which are basically BBC design heads made for an SBC.
Sure though, if you spend $50K on a small block, you can do some crazy things with it. Just the same as you can by spending $50K on pretty much anything else. Top Fuel dragsters are 500 cid Hemis though, and make 4-8x as much power as that engine is making. If you put a top fuel engine in that car, and could find some way to get enough fuel in it to last for 2 miles, and could keep the parts from wearing out, it'd blow that 439 MPH away. But the biggest problem at Bonneville is traction. Making enough power to go those speeds is easy.
[This message has been edited by dobey (edited 09-22-2015).]
Given that HP is a function of both RPM and torque, you can't simply eliminate it from any comparison. No street cars are spinning to 18000 RPM either, so if we're going to limit the discussion to what's only applicable to the street, then the upper RPM limit is really about 10000 RPM. On average, most small displacement 4 cylinder engines are not even spinning faster than 8500 RPM. It's certainly possible to spin an 8L engine to that speed, but the cost to do so will be much higher than for a small displacement engine.
I am not eliminating anything from any comparison. I simply stated that there are two definitions of "power" and two ways to get there, one with primarily displacement and torque, and one with primarily rotational speed and horsepower. What path you choose depends on your application and your goals. ICEs work on air over time, not air absolutely. How you process more air depends on what you want to do. There isn't one path, there isn't one answer. If there were, we'd still have 8l four cylinders like in the '20s. We've learned a lot, including how to get superior results from less metal spinning much faster. How and where you optimize is solely a function of what the end result needs to be.
[This message has been edited by thesameguy (edited 09-22-2015).]
LOL. I would hardly call that a typical small block Chevy.
8.5" deck height 4.125" bore 2.8" stroke
It has 2 160 lb/hr injectors for each cylinder, and at peak the turbo can push upwards of 50 PSI through. Everything about that engine is custom. The block is a custom from Dart. The heads are Dart Lil Chiefs, which are basically BBC design heads made for an SBC.
Sure though, if you spend $50K on a small block, you can do some crazy things with it. Just the same as you can by spending $50K on pretty much anything else. Top Fuel dragsters are 500 cid Hemis though, and make 4-8x as much power as that engine is making. If you put a top fuel engine in that car, and could find some way to get enough fuel in it to last for 2 miles, and could keep the parts from wearing out, it'd blow that 439 MPH away. But the biggest problem at Bonneville is traction. Making enough power to go those speeds is easy.
Those engines can't hold together that long. Youve been to bonneville? Live fast die hard is the creed out there. There was a 4 engine hemi that was faster than the sbc but that was years ago.
Engines are air pumps and the more air process the more fuel you can add and more HP and Torque.
Now you can use a 454 to move a specific volume and tune it with compression to make power and move torque with the cam and intake.
Or you can use a 2.0 Turbo 4 and make power with more boost to put more air in and add more fuel. Lower the torque with more compression because of the DI fuel injection that cools the cylinder. And then you can keep the torque curve flat with Variable Valve timing.
This is how I get 300 HP and 315 FT LBS from only 2.0 liters. Add 23 PSI to a 9.5 to 1 engine and then use DI to cut detonation and then control the cam timing with VVT you can make an engine much more efficient with less displacement. This is what all the companies are doing to a lesser degree. Note I do this on pump gas and still under GM warranty since it is a GM tune.
The point is you can make power different ways but the smaller engines with power do it more efficiently and with less emissions. That is why nearly all cars will offer Turbo 4 cylinder.
I never loved turbo engines or 4 cylinders but my SS is one hell of a fun car to drive. I just wish it was RWD. I get tired of trying to hook up the tires with out wheel spin or losing boost. I can spin the tires on dry pavement at over 50 MPH. If you can get it to hook up a 13;75 is possible. The really neat thing is the engine can go to 400 HP before you need to replace anything internal.
I get 25/32 MPG too driving hard.
Sorry but the sound sucks if you make it noisy. There is no way to fix that correctly. Two pipes help but often hurt power by 4-8 Hp.
I am not eliminating anything from any comparison. I simply stated that there are two definitions of "power" and two ways to get there, one with primarily displacement and torque, and one with primarily rotational speed and horsepower. What path you choose depends on your application and your goals. ICEs work on air over time, not air absolutely. How you process more air depends on what you want to do. There isn't one path, there isn't one answer. If there were, we'd still have 8l four cylinders like in the '20s. We've learned a lot, including how to get superior results from less metal spinning much faster. How and where you optimize is solely a function of what the end result needs to be.
What's wrong with 8 liter 4 cyls. Will it fit in a fiero?
Originally posted by Silvertown: Those engines can't hold together that long. Youve been to bonneville? Live fast die hard is the creed out there. There was a 4 engine hemi that was faster than the sbc but that was years ago.
The same car you linked to was previously using a hemi head 4 cylinder Mopar motor. Bonneville kils everything. Salt and metal don't go well together. Exactly, those engines can't hold together that long. The engine in that car takes a massive beating every time it gets run, and is an extremely expensive full race engine built to handle 50+ PSI of boost, and spin high RPMs. Which is why it has such a big bore, and such a short stroke. With that short of a deck height, the rods aren't too long either.
A single $50K full race engine example of an SBC isn't a good representation of the average SBC either. That thing is nothing like the dime-a-dozen SBCs you can bump into walking down the street.
The same car you linked to was previously using a hemi head 4 cylinder Mopar motor. Bonneville kils everything. Salt and metal don't go well together. Exactly, those engines can't hold together that long. The engine in that car takes a massive beating every time it gets run, and is an extremely expensive full race engine built to handle 50+ PSI of boost, and spin high RPMs. Which is why it has such a big bore, and such a short stroke. With that short of a deck height, the rods aren't too long either.
A single $50K full race engine example of an SBC isn't a good representation of the average SBC either. That thing is nothing like the dime-a-dozen SBCs you can bump into walking down the street.
That's really the only thing about Hemis is the heads. Had a guy tell me I was wasting my money by putting larger valves in a 3.8 with a super charger. It's all about the flow of air into the intake valves and out the exhaust and whoever does it fastest wins. That's why Hemis dominated at the dragstrip and in nascar but not on the street for some peculiar reason.
Originally posted by Silvertown: That's really the only thing about Hemis is the heads. Had a guy tell me I was wasting my money by putting larger valves in a 3.8 with a super charger. It's all about the flow of air into the intake valves and out the exhaust and whoever does it fastest wins. That's why Hemis dominated at the dragstrip and in nascar but not on the street for some peculiar reason.
The original SBC bathtub chamber heads are junk though. You're not going to make efficient power without good heads.
to make power you need air flow you could have a 600 inch engine and make 150 HP if the cylinder heads only flow 100 cfm on the intake port and 70 cfm on the exhaust port so and this is why all top race teams spend most of there money on getting the ports to flow right in other words to make 600 HP on a v8 no matter the displacment you need 300 cfm on the intake side and around 225 cfm on the exhasut . now it is different for a v6 or 4 cylinder becaus the have only 4 or 6 intake ports that flow 300 cfm each so the total flow of the engine is less . A 4 cylinder with intake ports that flow 300 cfm each is only going to have a total of 1200 cfm because 300 x 4 = 1200 where a 8 cyl is 300 x 8 =2400 cfm air flow and there are other factors such as displament of each cylinder on many rpm the engine will turn to make the power . last i will leave you this if it was just displacment then a 455 olds,pontiac,buick &454 chevy should all be able to make the same amount of power with there stock cylinder heads but the 454 chevy will alway make more power tha the other due to its heads flow way more air
Being mostly a Mopar guy, I can tell you a properly set up street 340 Mopar can kill a street 440 car. Both with 16v and single 4 bbl. Ive also watched 4bbl slant 6 (225 ci) with over 400 hp on gas.
looking at 1/4 mile times here. No Cobra even in the top 10, and quite a few on the list around 4.0 ltr. Bentley (at 6000 pnds) 4.0 ltr, matches Cobra (more or less) faster 0-60, same ET within a few hundreths.
Being mostly a Mopar guy, I can tell you a properly set up street 340 Mopar can kill a street 440 car. Both with 16v and single 4 bbl. Ive also watched 4bbl slant 6 (225 ci) with over 400 hp on gas.
looking at 1/4 mile times here. No Cobra even in the top 10, and quite a few on the list around 4.0 ltr. Bentley (at 6000 pnds) 4.0 ltr, matches Cobra (more or less) faster 0-60, same ET within a few hundreths.
I was taking a jab at ferrari. Shelby owned ferrari. But you'd be surprised at how much power you can get out of those 472s souped up. But there is no sweeter sound than a Ferrari full tilt. Almost bought a 340 ta cuda but the guy wouldn't budge on the price. But a 440? Those were faster than a hemi at that drags when they were new.
The same car you linked to was previously using a hemi head 4 cylinder Mopar motor. Bonneville kils everything. Salt and metal don't go well together. Exactly, those engines can't hold together that long. The engine in that car takes a massive beating every time it gets run, and is an extremely expensive full race engine built to handle 50+ PSI of boost, and spin high RPMs. Which is why it has such a big bore, and such a short stroke. With that short of a deck height, the rods aren't too long either.
A single $50K full race engine example of an SBC isn't a good representation of the average SBC either. That thing is nothing like the dime-a-dozen SBCs you can bump into walking down the street.[/QUOTE
It's still based on the original 1955 pushrod design. He's just using better technology. Chevys motto " if ain't broke don't fix it".
to make power you need air flow you could have a 600 inch engine and make 150 HP if the cylinder heads only flow 100 cfm on the intake port and 70 cfm on the exhaust port so and this is why all top race teams spend most of there money on getting the ports to flow right in other words to make 600 HP on a v8 no matter the displacment you need 300 cfm on the intake side and around 225 cfm on the exhasut . now it is different for a v6 or 4 cylinder becaus the have only 4 or 6 intake ports that flow 300 cfm each so the total flow of the engine is less . A 4 cylinder with intake ports that flow 300 cfm each is only going to have a total of 1200 cfm because 300 x 4 = 1200 where a 8 cyl is 300 x 8 =2400 cfm air flow and there are other factors such as displament of each cylinder on many rpm the engine will turn to make the power . last i will leave you this if it was just displacment then a 455 olds,pontiac,buick &454 chevy should all be able to make the same amount of power with there stock cylinder heads but the 454 chevy will alway make more power tha the other due to its heads flow way more air
Huh? Head flow requirements are directly relational to static engine displacement, and RPM. It's a linear progression. You don't need intake flowing 300 CFM per cylinder to make 600 HP. There's a hell of a lot more to making HP numbers than head flow and displacement. A 6.0L engine only needs about 1060 CFM at 100% VE, at 10000 RPM. That's about 132.5 CFM per cylinder. What you need, is the correct head, valve, intake manifold, throttle body, and camshaft combination to acheive that. A stock LS2 can flow about 230 CFM average between 0.450-0.650 lift. The reason the stock LS2 can't hit 10000 RPM, is due to materials issues. That engine makes 400 HP in stock configuration. Cam, 1.8 rockers, and a tune can easily take it 600 HP NA, and the heads don't flow 300 CFM. Simply bolt on a turbo that's pushing ~8 PSI, and you'll be over 600 HP.
I don't know where you got this notion that any head must flow 300 CFM on the intake, in order for an engine to make power (specifically, HP), but it's wrong. Bolting 300 CFM heads onto an engine with a crappy cam and low compression ratio isn't going to magically give you lots of power. You need the whole combination, not just one little thing.
Originally posted by Silvertown: It's still based on the original 1955 pushrod design. He's just using better technology. Chevys motto " if ain't broke don't fix it".
The heads are not the SBC design. The deck height is shorter. The mains are stronger.
Clearly something was broke, because Dart did a lot of fixing to the original design, in that engine.
remember the flow numbers on the head i am talking about are flow bench numbers at 28 inches of water and your talking about how much air flow it take to make a certain amount of power and the engine can not achieve 28 inches of vacuum because the air is being pushed into the engine with atmospheric pressure 14.8 so flow bench number are just a tool to tell how much air the head can flow at a certain vacuum . most shops use 28 inches but there are some shops who use 25 and you must use a correction factor when comparing heads so dobey you are right but so am i, you are just saying what it needs to flow on the engine and i am saying what it needs to flow on a flow bench at 28 inches to make that power
[This message has been edited by engine man (edited 09-23-2015).]
remember the flow numbers on the head i am talking about are flow bench numbers at 28 inches of vacuum and your talking about how much air flow it take to make a certain amount of power and the engine can not achieve 28 inches of vacuum because the air is being pushed into the engine with atmospheric pressure 14.8 so flow bench number are just a tool to tell how much air the head can flow at a certain vacuum . most shops use 28 inches but there are some shops who use 25 and you must use a correction factor when comparing heads so dobey you are right but so am i, you just saying what it needs to flow on the engine and i am saying what it needs to flow on a flow bench at 28 inches to make that power
No, I am saying you are misguided in thinking that you need heads that flow 300 CFM on a flow bench, in order to make 600 HP.
And the 28 inches WC measurement is the pressure difference across the orifice. The air flowing into the head from outside is at atmospheric pressure in both the car, and at the flow bench. 28 inches WC is about 1.012 PSI difference in pressure, which means the chamber side of the bench orifice is at about 13.7 PSI, at sea level. What do you think the pressure in the cylinder for a running engine is, when the intake valve opens? It's definitely not 0 PSI, but it's not 14.8 PSI either.
It changes as the piston falls in the cylinder, and the intake valve opens up further, and since the intake valve closes after BDC, and there is some overlap with exhaust valve closing, when the intake valve opens, the cylinder pressure should never reach 0, and won't fill the cylinder completely. That's where dynamic compression ratio comes from.
Head design, valve lift, cam timing, compression ratio, stroke, etc… all affect how much power you can make.
lets take a 350 chevy now each cylinder is 43.75 cubic inches now lets convert that to cubic feet .025318287 cubic feet for every intake stroke so how fast is that piston going to have be moving away form tdc to achive 28 inches of water on the combution chamber side of a head that flows 300 cfm on the flow bench with the valve open . See i went to School for this at the School of Automotive Machinist Huston TX and unless they are teaching their students wrong
[This message has been edited by engine man (edited 09-24-2015).]
Originally posted by engine man: lets take a 350 chevy now each cylinder is 43.75 cubic inches now lets convert that to cubic feet 3.64 cubic feet for every intake stroke so how fast is that piston going to have be moving away form tdc to achive 28 inches of vacuum on the combution chamber side of a head that flows 300 cfm on the flow bench with the valve open . See i went to School for this at the School of Automotive Machinist Huston TX and unless they are teaching their students wrong
You keep saying "28 inches of vacuum." That is not the measurement used on a flow bench. It is 28 inches of water column. That measurement is the pressure difference across the orifice. That is roughly equivalent to 1 PSI difference across the orifice.
You seem to be wanting to ignore all the other parts of the engine. Just because an engine is N liters, doesn't mean it's pumping N liters of air through it with every 2 revolutions of the crank. Power is a function of all components of the engine, and not simply a function of how much air the intake port of your heads can flow at some lift your valves may never even reach.
you right 28 inch of water but any way it takes allot if you ever heard a flow bench you would think a small jet is taking off as they are moving allot of air thousands of CFM
The heads are not the SBC design. The deck height is shorter. The mains are stronger.
Clearly something was broke, because Dart did a lot of fixing to the original design, in that engine.
It's new territory. Everything breaks at that level. But good luck hoping a ford or dodge beats it cause there not that adaptable. On the street, strip or track the sbc dominates excluding top fuel.
you right 28 inch of water but any way it takes allot if you ever heard a flow bench you would think a small jet is taking off as they are moving allot of air thousands of CFM
I have a small flow bench right here in my house. The air pump is only moving as much air as will move through the orifice though. Unless you're measuring the flow on something that flows "thousands of CFM" then it is not flowing thousands of CFM.
It can only flow as much air as the most restrictive part of the system (the item being measured, typically), will allow.
you are right the whole engine must be a package just because it is 6 L wont make it make x amount of power it must have the right heads cam intake exhaust and strong enough parts to handle the rpm but a 4 cyl will have to work harder / more rpms due to it has less cylinders and ports to move the air thru in theory you could build a 6 liter 4 cylinder with huge ports but the internal parts would be so big and heavy it would be hard to get to the rpm needed to make power
It's new territory. Everything breaks at that level. But good luck hoping a ford or dodge beats it cause there not that adaptable. On the street, strip or track the sbc dominates excluding top fuel.
Back when I was going to the drag strip every Sunday, small blocks were most definitely not dominant. BBC or Pontiac V8s were what dominated most of the sportsman IHRA classes. Bracket racing was something completely different; it was always up in the air who would win bracket races. We were dominating the Top Dragster class with a big 632 Pontiac though.
dobey since you have a flow bench then you must have read that a V8 will make about 2 hp for every cfm of flow you have on a flow bench. this is from this web site http://www.speedstore.ca/flow_testing.html the simple mathematical formula for calculating potential power for a V8 engine is to multiply the maximum flow bench CFM test data at 28 inches of test pressure by 2 to get the estimated horsepower capability. This means that porting modifications to cylinder heads and intake manifolds that increase airflow by 1 CFM can produce 2 horsepower in a V8 engine (1 CFM x .255 x 8 Cylinders = 2.04 HP). just get any porting book and they will say the same thing
Flow Bench The horsepower potential of an engine can be calculated by the airflow capability of the cylinder head and intake manifold. Airflow testing of cylinder heads and intake manifolds can be conducted on a flow bench. Horsepower calculations can be estimated from the flow bench test data as follows: The standard measure for flow testing is 28" of test pressure on a Superflow 600 flow bench. The formula for calculating horsepower from flow test data measured at 28" of test pressure is as follows:
HP = 0.255 x flow test data at 28 inches of test pressure
Example: Intake airflow of 250 cfm at 28" of test pressure can produce 510 hp. 250 cfm x .255 = 63.75 hp per cylinder 63.75 hp per cylinder x 8 cylinders = 510 hp.
[This message has been edited by engine man (edited 09-23-2015).]
Back when I was going to the drag strip every Sunday, small blocks were most definitely not dominant. BBC or Pontiac V8s were what dominated most of the sportsman IHRA classes. Bracket racing was something completely different; it was always up in the air who would win bracket races. We were dominating the Top Dragster class with a big 632 Pontiac though.
That's back in the day. Pontiacs dead. What engine were trans ams running from 1982-02? Had an ls5 chevelle that could pull its front wheels of the ground but a LT1 z28 could take its lunch money. Go to lemans where corvettes have dominated for the last umpteen years. But for some unknown reason chevrolet has never put forth the effort like the other mfgs at the strip, imo.
I was taking a jab at ferrari. Shelby owned ferrari. But you'd be surprised at how much power you can get out of those 472s souped up. But there is no sweeter sound than a Ferrari full tilt. Almost bought a 340 ta cuda but the guy wouldn't budge on the price. But a 440? Those were faster than a hemi at that drags when they were new.
Ya, your right Ford did hand Ferrari its butt in the mid 60s..at least in sports car racing. Ford gave them an unlimited budget to do just that. Saying NO FERRARI is a bit of a stretch though. Street Hemi just used the reputation, no question 440s are bad. The 'street' Hemi you bought at dealer was a LOT different. It had the same heads, but they used hydraulic lifters and detuned it quite a bit from the 'real' Hemi. The original 426 required way to much upkeep for the regular driver. Just as they could beat the 440, the 340 could also beat the Hemi. The best Hemi was actually not the 426...but the 392. Back in my day, all the top dragsters always built up a 392 and pretty much ignored the 426. They might put the 426 emblems and logo on, but that was more for the publicity. They did also make a 426 without the Hemi heads.
I have read a lot of things. It doesn't mean they are true or accurate, though.
Peak flow measured through the intake is only a tiny part of the problem. If that number is measured at 0.650", and your cam and rockers only give you 0.500" of lift, then you'll never flow that number through the head, even for the tiniest fraction of a second that a cam holds the lifter at peak. Likewise, if the intake manifold can't supply enough air, then the flow number on the head itself isn't what you're getting.
Then there's forced induction to consider. Take everything you thought you knew about head flow, and throw it out the window. The more boost pressure you run, the less important the peak head flow numbers are.
You don't need higher peak flow numbers, to get a higher cylinder pressure, either. Changing the cam profile can do that. Changing the compression ratio will do it. Forced induction does it. Nitrous does it. Changing ignition timing can do it. Other things can to. Just because your heads can flow a certain CFM, doesn't mean you're necessarily going to make more power.
Originally posted by Silvertown: That's back in the day. Pontiacs dead. What engine were trans ams running from 1982-02? Had an ls5 chevelle that could pull its front wheels of the ground but a LT1 z28 could take its lunch money. Go to lemans where corvettes have dominated for the last umpteen years. But for some unknown reason chevrolet has never put forth the effort like the other mfgs at the strip, imo.
Back in the day as in 1999. Just because Pontiac the company doesn't exist any more, and wasn't making their own V8 production engines for the last N years, doesn't mean the platform itself is dead. If it did, this forum wouldn't be here, because, you know, Pontiac's dead.
Are we talking about drag racing, street cars, or LeMans? Make up your mind. SBC does not dominate them all. Chevrolet/Cadillac have certainly been dominating their respective racing circuits, sure. There is a huge difference between the Gen IV and V engines, than what people mean when they say "SBC" though. When people say "SBC" they mean the first generation engines. When they talk about the Gen II engines, they say LT, when they talk about Gen III/IV engines, they say LS, and when they talk about Gen V engines, it's hard to know, because most people still seem to be quite confused by what they are. Some still call the Gen V engines LS engines, but they're quite different from the Gen III/IV engines.
Wow i am sure all the top head porters in the world like Stan Wiss who has written books would love to know this info or maybe you can go tell one of those top fuel teams they don't need those big ports to shove air thru just up the boost
Wow i am sure all the top head porters in the world like Stan Wiss who has written books would love to know this info or maybe you can go tell one of those top fuel teams they don't need those big ports to shove air thru just up the boost
Wow, could you be more condescending if you tried?
There is a huge difference between building custom billet blowers, heads, and engine blocks, to make 8000 HP in an engine that needs rebuilt every couple of passes, than making 600-1200 HP in a street car.
But if you want a car that makes 8000 HP and only goes about 50 feet with a gallon of fuel, sure, put a top fuel engine in your car.
Seriously though, I've heard it mentioned numerous times that the 3800 sounds crummy because it's basically a V8 with two cylinders lopped off. This makes for an odd sounding firing order. The 3800 was never designed from the ground up as a V6, such as the lowly 2.8 was (which by the way, sounds pretty good).
Yea it can, but it also can sound pretty decent in a Fiero with the right setup and exhaust pipe sizing.
