That video was just being used as an example of the RPM potential. On a smaller displaced SBC, the RPM potential would be even greater. I mentioned above that Russ also offers 32-valve street heads, and although he does in fact ask for quite a bit of money for them, they are worth it in the end as far as I'm concerned. Throw a turbo on a 32-valve L98 w/MiniRam setup and it will honestly embarrass most boosted LSx engines...

http://araoengineering.com/pakages.htm

 

It is very impressive that a company designed a 32 valve head for a small block chevy that was never designed for it. I would honestly love to throw a set on a small block just for bragging rights. Too bad they are so much money! And as far as LSx engines, they aren't the "end all" motor that everybody thinks they are, but they def designed a pretty kickin cylinder head with only 2 valves and pushrods still. I have seen some LSx engines that made HUGE power where a small block chevy equivelant with similiar parts would not be so impressive. It helps that they have one of the best and most precise PCM's ever designed too, from the factory. Sequential fuel injection and coil per cylinder on a SBC I'm sure would net pretty respectable numbers too, as S10wildside on here has proven.

 

"""Okay, let's put things into perspective here. The Chevy V8 wasn't designed to rev to 8000-RPM stock, so bringing it that high in the RPM band would be completely meaningless, it would only hurt performance. Also, you mentioned earlier that a true mechanic would know that any car built right can be fast, well my response to that is that a true mechanic would also know that RPM isn't the only thing that depicts what an engine is capable of. We build engines around their RPM potential, meaning how much air is literally being consumed during quench. If an engine's bore size isn't taking in the amount of air necessary to maximize the cubic inch displacement, then RPM's will obviously suffer because the engine is being choked. I also don't see you comparing your 4-banger with Chevy's new LFX V6 engine. Getting back to V8's though, put a set of 32-valve heads on any SBC, then test your theory again about RPM ability. Here is a good example, a big inch SBC with 32-valve heads. Mind you, this is a race engine, but Russ also offers street heads with the same RPM potential for any SBC, making power throughout the RPM band WITHOUT the need for variable valve timing..."""

Almost in your entire post did you miss what I was saying. Hondas arent really designed to rev that high either but can stock. There are many reasons why they rev higher one being there power band they dont have low down torque like v8's do because well they dont have another 4 cylinders helping and the crank dimensions as far as stroke are a little different. Ok sure throw a 32 valve head on a v8 and watch it rev high ok thats fine but did you ever see the size of the valves in a 1.6 litre or even 2.0 4 cylinder engine? There tiny. Most stock intake valves of v8's are almost equivelent in size of both intake valves that of a 4 cylinder. I also wasnt stating the rpm as an abillity over the v8 just simply that thats where 4 cylinder make there power.

Go spend well over a grand on those race heads alone and for the same money that you buy those heads I would have machined and built my own 4 cylinder head and even furth raised the rpm potential into the 9500rpm range. I built a b16 1.6 litre dual over head cam a few years back in which my powerband just barely started to drop out at 8600rpm it was a nitrous build I did that ran 10.8's in a 94 civic hatchback. Definately wasnt street legal due to smog and being in california which considers a air intake illegal modifcation but on street tires still ran mid 11's stock bottom built and shaved head, ported and polished and a aftermarket intake manifold with a 125 shot of nitrous.

I did not mention anything about the new chevy lfx engine. I was keeping a basic note not calling out every detail on every engine just basics. The new v6's are cool and definately a good platform but I do not know to much about them to be honest but have heard plenty of good things. Im not biased between imports and muscle so please do not take anything I write in that tone.

Radical might have been a little edgy of a word to use as I should have figured most would take it to literally. These cam only 10 second v8's are coming from high performance cars already and already have mods done from factory. There is no cam only 350 427 454's lt1's ls1's in there original cars that run 10's cam only without supporting mods. Now this cam only engine I am interested in hearing about. I could drop a ls1 in a datsun 510 and run low 11's stock probably faster but then lets not forget to be fast in the quarter good suspension is a major factor. This is one of those arguments that can just go on and on but literally there is no better car in the end. It depends on your wallet and what you plan to do.

 

That is wrong. The reason why a smaller engine seems to rev higher from the factory is because of the volume of air "through" intake tract. Tuned Port Injected V8's have a hard time reaching past 4500-RPM's, but that is NOT because they are V8's, but because of the volume of the system that it came with. Put a stock TPI system on a 283 V8 and the engine will rev higher than 4500-RPM, put a stock TPI system on a 454-SBC and the engine will rev lower than 4500-RPM. It is the VOLUME OF AIR that dictates where your RPM band will be. Incidently, a destroked 400 (377) is meant to reach 8000+ RPM's, but again, the intake (heads, cam, manifold, carb, throttle body, etc.) dictates if that will happen or not. ANY engine can rev to the moon, it just needs to breath...

THINK of what your saying, think of the bore/stroke and amount of valves per cylinder these little engines are utilizing, and you will immediately see why they can accomplish that, and that is because they are not as restricted in the RPM band as most factory V8's are. They can breath throughout, there are no obstructions for them. Forget about Honda's for a second, and think of your average L98, then think of your average LT5 (early 90's, not the new one's). Both are 350 V8's, yet one is capped at 4500-RPM, while the other can shoot way past 7000-RPM. Why is that? It is because the LT5 see's more usable air up top because it can breath, and in turn can burn more fuel. Air + fuel = power within any area in the RPM band, doesn't matter what engine your using, because all an engine is is a giant air pump...

Again, THINK of what your saying. The diameter of the valve size may be similiar in your example, but think of the area below the valves, the bore. Here is an example that maybe you will understand. Get two straws of the same size, then hand one straw to a five year old kid, and the other to a grown man. Their mouths (valve diameter) are essentially the same size, but their lungs (bore) are an entirely different size. Who will have an easier time breathing? Make better sense...?

So what lol? Let me explain something to you, it takes x amount of horsepower accompanied by weight and gearing to run a number. While your raising your RPM potential, I will focus on weight, gearing and tire size, keep the engine at 6000-RPM, and blow your doors off. How can you not know that as a mechanic? Even the Buick guys know this, and got it down to a science...

Oh really? What did that car weigh? Put that same engine of yours in a 3500-pound F-body and see what you run then. You have this delusion that RPM's equal more power, and the only reason that is so is because the engines in which you are referring to make absolutely no torque down low, so you need to wind them up like a sewing machine on steroids. There is way more to racing and engine performance than you think. While your "revving" up to 8600-RPM looking to squeeze more power out of your 4 banger, my boy Donnie is keeping things below 6000-RPM with a 1.83"/1.50" SINGLE intake valve per cylinder 3.8 PUSHROD Buick engine and running faster than you ever will with a vehicle weighing as heavy as his...


8.76 et & 158.69 mph...




Are you kidding me? What exactly are you referring to when you say supporting mods? Are you referring to suspension tweaking, because that is an obvious for any car running those numbers, not to mention the track won't allow faster than 11.50 without a rollbar. I will show you a stock LS1 in a full weight 4th gen with T-Rex cam only, and I am showing you this car because I know the car, it used to run by me...



Let's keep the discussion on track (pun intended lol), we are discussing RPM potential, and why your saying a V8 won't rev as high as your 4-banger. Putting a cam only LS1 in a Datsun is besides the point, as the vehicle is much lighter, and every 100 pounds equates to a tenth in ET anyway...

I will agree with that, however, you will always make more power with more cubic inches, always. I have seen 4 cylinders running extremely fast at the track, but in the end on the dyno, not to mention top speed on the highway, you will always make more power with cubic inches. Cubic inches = torque, and more torque means more calculated horsepower...

 

71ChevelleSS, ask yourself this, and I will use those 32-valve heads that I posted as part of the example. Take any L98 engine, bone stock. Now, we all know that they lose power after 4500-RPM, and have a hard time even escalating above that on the highway. Now, throw in a camshaft without touching anything else, let's say a CC306 cam from Comp (230/244 510/540). Will the engine now have a rough idle, and why? Okay, we'll take it up a notch, same engine, same cam, but now we will install those 32-valve cylinder heads and better flowing Miniram intake manifold w/58mm throttle body. Again, same short block, same cam, but different heads, different intake manifold, and different throttle body. Does the engine have as much of the same rough idle, and why not...?

 

Same concept of why a supercharger on a 4.6 liter may make 7 lbs of boost, but the same supercharger on a 6.0 liter will only make 4 lbs of boost. You have a larger air requirement on the bigger motor and are filling a larger cylinder bore so you lose boost without changing anything.


While the size of the valves on a 4 banger with multiple valves per cylinder is small, they flow a considerable amount due to the amount of area around each valve. Trying to suck air around one larger valve (V8) is a bit harder than trying to suck air around multiple smaller valves (I4), in most cases that is. A smaller bore will def require much less head flow however than a bigger V8 bore, talking N/A that is.


In a way, that is true. Theres obviously a lot of factors that base what an engine will produce for power...examples being bore, stroke, compression, timing, etc. Take 2 identicle engines though; one with a very large cam and one with a smaller but still adequate cam. The one with the larger cam will make more power granted the heads and intake can support it. As long as you can supply the air requirements, a larger cam will always produce more power because it allows the engine to spin higher up to create it. Now if you were talking a 1.6 compared to a 5.7, then no, higher RPM does not equal more power. Only on the same size engines is this statement true.


I understand what your saying, but boost is the answer to dispacement problems. Sure, if both engines had boost the bigger one would make more. Although bigger displacement doesn't always mean more torque. My brothers old lancer evolution made 348 lbs ft of torque at an amazing 2800 or so RPM. There are not too many V8's that can even boast of making it that early on in the RPM band. It's because the 2.0 motor coupled with the small turbo he had spooled instantly and produced a ton of torque. That car would literally jump out on all the V8's he raced, even from a roll, and some would creep back top end because they made more HP. I loved the feeling it gave when you rode in it. Just smashed you into your seat!

 

Bingo. Boost readings are just resistance readings, they aren't really telling you how much air is entering an engine bore, they are just telling you how hard the blower is working to achieve x amount of air through a particular valve size at a particular RPM. Once you alter the intake tract the boost reading changes. Tighten (restrict) the tract, and boost pressure will rise, open the tract and boost pressure goes down...

Exactly, not to mention we must factor in the literal size of the bore, as well as stroke, as less cubic inch displacement will require much less volume to feed from, in turn being able to spin high in the RPM band because it essentially has no restriction. The diameter of the intake tract in a 4 banger is enough to feed the engine throughout the RPM band. This is why when we siamese the TPI system, and/or throw on an LT1/HSR in it's place, our RPM potential immediately increases... because not only has the volume of air opened up in which the engine feeds from, but the distance from the plenum to the cylinder heads has shortened significantly...

Absolutely, which is why a 1.94" intake valve is more than enough to feed and satisfy the requirement of any 305 small block chevy. Larger engines, with larger bores, will benefit from a larger valve, of course. Four valves per cylinder in a V8, or any engine for that matter is ideal, because it increases the volume of air just before the bore of the engine, allowing it to spin much faster throughout. It is almost as if it acts like a secondary plenum to feed from just above the bore, as that is literally how much volume of air is in the bowl to feed from....

Honestly depends on the valvetrain if we're comparing 5.7 vs 5.7...

Not in the 4 banger's case. At the track, yes, because most 4-bangers running turbo's run race gas and meth when they run sub nine second passes so boost definitely becomes an answer for them, but when they run pump gas they run into major problems. V8's with more cubic inch displacement can get away with much less boost while running pump gas, but once we apply more boost and methanol to the V8 it is game over. There is a reason why top fuel dragsters own the 1/4 mile...

Oh, but it does. More cubic inch displacement allows for more air and fuel, and that is what horsepower is. The more potential for more fuel, the more horsepower we make. Granted, there are cases where 454's might make less than say a 427, but this highly depends on the variables; cam, compression, etc...

Your brother's Lancer made that much power at 2800-RPM with how much boost? Here is a old school Pontiac V8 running a turbo charger just like your brother's old Lancer, see how much torque it made at 3400-RPM at less than 10-psi throughout the RPM band...

RPM/Torque/HP/Boost-PSI

3,400 744 495 8
3,600 734 503 8
3,800 718 519 8
4,000 699 532 9
4,200 671 537 8
4,400 641 537 8
4,600 611 536 8
4,800 565 516 7
5,000 532 506 7
5,200 506 501 7
5,400 478 492 7
5,600 450 479 7

http://www.carcraft.com/techarticles...arts_list.html

It wasn't because it was a 2.0 that made it spool instantly, it was the exhaust backpressure to intake pressure ratio that did that. Any engine with a 2:00+ ratio will spool the turbo instantaneously...

 

a bolt on l98 or bolt on lt1 will make more torque than 348ft/lbs at 2800 rpm than that evo.lol

 

Really? Because this dyno graph of an LT1 with underdrive pulleys only shows around 315 lbs ft at 2800 RPM.

http://www.ws6.com/mod-2.htm

I really can't see headers and an intake producing another 30 lbs ft at that RPM. But regardless, even if it did, we are comparing it to a little 2.0 with a tiny turbo running pump gas. For a 4 cylinder engine, even turbo, that is excellent low end torque.


And Street Lethal, The evo was running 26 PSI on pump gas with methanol injection. But it was the stock turbo which on an evo is very small. I wasn't saying that a turbo I4 makes more torque than a turbo V8, because turbos will increase the torque substantially on any motor...I was just saying that on a small I4, a turbo will compensate for the small engines lack of torque that low in the powerband. I also just asked my brother and he said it was actually 351 lbs ft of torque at about 2800. Pretty impressive if you ask me!

 

bolt-ons, not just 1 bolt on like an underdrive pulley.Also,what gears did that Lt1 have? 2.73? 342? makes a difference.

 

I'm not sure exactly how an LT1 would respond, but generally, freeing up the airflow of an engine raises the HP/torque powerband. Meaning headers, intake, etc technically should raise where the torque comes into play. And since when do gears make any difference whatsoever on the HP/torque output of a motor? They spin the wheels faster, thats about it. I've heard that you MAY see a few lbs ft of torque going to steeper gears but I've never personally seen it.

 

A few pounds of torque from a gear swap? How about 25 % more torque from a gear swap. That is more like it. So you are trying to tell me that i only gained a few pounds of torque from stepping up to 3.42 gears? I gained like 3 car spaces. Yes, better gears will spin the wheels faster. Isn't a dyno measuring at the rear wheels?

 

I think your facts are a little off. Gears do NOT increase an engines torque output whatsoever. Ask yourself this....how can you increase the torque on an engine by replacing the rear gears which have nothing to do with the engines output? Are you saying that if I bought a bone stock LS1 camaro and went from 3.42 gears to 4.10 gear that the cars torque output would suddenly go up by 25%? It makes the car faster because it allows it to come into it's powerband quicker due to the increased tire rotation. It has absolutely no effect on engine output. Gears make a car faster, but not by actually adding any HP or torque.

Now I'm just waiting for somebody else to chime in here...

 

Gears are a torque multiplier.

 

In simple terms, technically rear end gears could increase rwtq due to mechanical advantage but only very slightly and at the same time you trade off rpm (hp) at the wheels (again only slightly). It all ends up with essentially zero change in power/torque output at the wheels. And it's all relative anyways since the only available power/tq is from the engine so it's just how it's manipulated, trading hp for tq and vice versa.

As for the 25% statement thats TOTAL BS if he's taking dyno numbers, you are correct it just allows the car to better utilize it's tq/hp

 

This debate comes up all the time and the short answer for seeing rear wheel gains on a dyno with a steeper gear install is no. Countless magazines have tested it and some actually have lost a bit of torque going to a steeper gear. They feel like a multiplier because they keep the engine at a higher RPM where it has more torque and power, but they don't physically add torque.

 

There's no debate, gears ARE torque multipliers. That is exactly how they work.

They take the available torque from the engine (or other motor), and multiply it by the ratio of the gear.

Putting it simply a 2:1 gear would multiply the input torque by 2.

 

I understand exactly how they work, but I'm saying you won't see a difference on a dyno, and they surely will not make the engines output change whatsoever.

A rear gear change is the exact same thing as dynoing a car in 3rd gear as opposed to 4th gear. 4th is ussually 1:1 where as 3rd is a bit steeper...I had tried multiple gears on my old mustang and the power rating always showed the same on the dyno.

Gears change the rate of acceleration, not actual torque output.

 

I think you may be right .Maybe i should have looked at it like riding a bicycle. For the same amount of energy that someone would peddle, changing to a lower gear would yield faster acceleration from a start to about midrange or so. After that changing to a higher gear (smaller sprocket on a bicycle) would then yield even greater acceleration for the same amount of energy/force.

 

I do recall reading somewhere that lower gear would give you about 25% more torque? Maybe it is "like" having 25% more torque in a sense.

 

Sounds like you may be remembering it wrong or have read it wrong. Gears will not give you more tq.

 

I beleive some of you have not takin a few things into account, as far as stock for stock youve lost your marbles, the only reason a for banger can even keep up or pass a v8 is (SMOG) and you can thank the governmentfor that one... the fact that exhaust is cycled back through our V8's is BS. Most 4of banger cars are built for the exact power rating it can put out basses on the parts giving. Every v8 car is smacked with handcuffs by the gov and tone em down, MAJOR down tuning, tit for tat your wrong about the best production motors ever. Buy the way who cares about 7 or 8000 rpm in a 4sec banger or whaterever those DOHC's are rated at most 6000 rpms... Haha the rest is just noise and I can't stand hearing it YOUR NOT MAKING ANY POWER YOUR CURVE HAS ENDED... anyway half the cylinders half the power and if you feel otherwise challenge me but do your math first

 

Odd place to jump in.

 

Hey, no big deal. I had questioned it at one point in time too, which is why I did a bunch of research and found out how they work. Glad I could pass on some info!

Engines were smogged down back in the 70's and early 80's....not today though. Yet 4 cylinders are still able to be built to hang with a lot of V8's. When GM is making 505 HP out of a 427 cubic inch corvette engine, nobodys going to tell me that engine is "govt smogged."

And have you ever actually seen a healthy DOHC 4 cylinders dyno graph? Trust me, they make power past 6000 RPM. Some will pull to 9000 RPM. It's not all noise, I assure you.

You have the internet right in front of you...you could have challenged yourself and won with some newfound info about 4 cylinder engines.

 

Once upon a time, I removed the air pump and EGR and tuned it out of the prom, filled the EGR passages in the cylinder head, and removed the catalytic converter in favor for straight pipe. Go ahead, ask me how much horsepower I gained...

 

There is nothing wrong with a screaming 4 cylinder in a lightweight car, except the noise, my uncle has a screaming v8 that sounds like 10 chainsaw's at 11000 rpms and he is making 700 ft pounds, yes daily driver, kinda hard for me to to take away from a v8 and give to 4 banger its what ev,

 

I'll bite....how much? Next to nothing I am guessing judging by the rant it looks like you are forming.

 

Well, let's hear it

 

I've riddin in Evo's, sti's, tegra's, DSM, jdm, there's enough hp for a golf cart, there is little torque its just not fun, they are always underpowered, I always want more power more than 4cyl can provide... that's why im on to big power

 

The rant that I am forming? Correct, the results yielded nada in terms of HP, unless you consider loss of mpg, and crappy exhaust note during deceleration as some type of a gain...



See above...

 

^This man speaks truth

 

I admit I loved my four banger but it wasn't an "import."

It was fast.

 

In all fairness, smog and fuel efficiency regulations play a big part in head, cam, intake, and exhaust selection from the factories.

 

11000 rpms??? c'mon man.
PS, 10 chainsaws at once would sound annoying, not cool.

 

I can't believe this thread is still going on.

 

I agree, but in terms of exhaust gas recirculation, the recycled gases in a naturally aspirated condition do no effect quench in the least, in fact, the inner EGR ports in the bowls in which the bores "pull" from only allow for more unused air and fuel to make it's way into the cylinder for increased power, not to mention a tad more RPM to play with. Mind you, the exhaust gas is a tad hotter, which is the unfortunate trade off, but by no means is it really detrimental. In boosted turbo conditions of course, sure, the hot air from the EGR ports only increases the chances of detonation because EGT's can reach over 1500 degrees, but it only really becomes detrimental because of the fuel we are using. Smokey Yunick was notorious for pointing that out....

As for the air pump, the only drawback is really the drag and resistance from the pulley, which really isn't that significant when you do a before and after on the dyno. The catalytic converter, well, I see cars running sub ten second time slips with them, so to me they are not really a drawback. If your engine is making power, it is making power, and no smog requirement is really going to slow it down. Maybe a tad from the dyno's perspective, but I have yet to see all the stuff being removed allowing for even a tenth in the quarter mile...

 

A turbo car needs egr. It can be done away with on a N/A car tho.

 

No it doesn't. Turbo racers fill the EGR ports with magnesium...

 

Who told you that? Having No egr will raise combustion chamber temps increasing chance of detonation. Not to mention a turbo car runs off of exhaust gas reciruclating

 

I have tested that method myself on my own turbo cars. You need egr on them.

 

My friend, you are greatly confused. Who told me that lol? I race an '87 Grand National, and have been around turbo buicks for a decade. Champion GN1's and ported irons all come with the EGR filled because it is essentially usless, and turbine wheels on a turbo spin from the exhaust gas leaving the cylinder head, it has nothing to do with the EGR ports whatsoever. EGR stands for exhaust gas recirculation and it distributes a portion of the exhaust gases back to the cylinders. What's next, are you going to state that EGT's do not reach over 1500 in turbo applications lol...?

 

You have tested nothing, and you are full of it. Show me something factual from your data...

Were these findings of yours from your "Stage 4" turbo...?

 

You need egr on a turbo car. Go ahead and re-connect your egr and see. Egr cools down combustion temps. Yes, it is a big vacuum and that part of it would be nice to get rid of , but the truth of the matter is: You need it more on a turbo car than a N/A car. Yes, I have tested it. I was into turbo over 15 years ago.

 

You need to understand EGR better my friend. Go research it and you will see. I bet it cools down combustion temps in an engine. Allowing the use of more timing and overall less chance of detonation.

 

That didn't prove anything. You clearly said that a turbo car needs EGR, and there was nothing factual presented in your response. EGR does not "cool" down the intake charge, it recycles unburned fuel after already being subjected to quench. I want you to show me FACTUAL air temperature and exhaust gas temperature data from a before and after test. Do you have any, or must I go on your word alone? EGR is a smog requirement, nothing more. Again, there is a reason why turbo racers eliminate and fill the EGR ports in their cylinder heads while blocking it off on their intake manifolds, and that is to help the "flow" of the exhaust gases to help reduce overcome the amount of backpressure and lag, not to mention cleaning up the engine bay. EGR does not make a turbo engine more efficient from a horsepower perspective, it is more detrimental in a turbo application...

 

Your words are nothing more than incoherent babble trying desperately to sound as if they are making a coherent point. You have shown everyone nothing with your data, only opinionated speculation. You are clueless. Perhaps you need to let go of the nonsense that you "ran" a stage 4 turbo 15 years ago, and stop parroting what you hear on the internet.

 

No, uh uh. Go ahead and find a factory turbo car and disconnect and plug the egr valve. Hmm, feel a loss in power? Now try and raise the boost a little. Now, try raising it with the egr connected. Disconnecting EGR on a turbo car will result in a LOSS of power.

 

Even disconnecting the egr without raising the boost pressure will result in a loss of power on a turbo car. I know from testing it myself. If you want the lowdown on egr. Here is a link http://www.diycardoctor.com/egr_valve.htm Even there it explains how egr cools down combustion temps and lowers the burn temperature. Heat is the enemy in a turbo car. A turbo car is a whole different beast than a N/A car.

 

Oh my goodness, you are dense lmao! Also, you are the one who is speculating, so YOU need to back up your words with factual data to prove yourself correct. you can't, so just let it go because you made yourself look foolish enough already. You have no idea what EGR represents, allow me to help you understand the meaning behind the system in general...;

The EGR system serves to route exhaust gases, which are inert to the combustion process (because they have already been 'combusted'), back into the intake manifold. This is done to 'dilute' the intake air into the cylinders so that there is less available oxygen for the combustion process. This lowers combustion temperatures, which, thereby also lowers the formation of nitrogen compounds (NOx)...

You are confused in a narrowing world my friend. Come back with your results next time...

 

So, I guess i will strap my shoes on and head down to the local dyno just for you. You are the one making yourself look foolish by starting with the fighting words again. You call someone dense on a forum? EGR is needed on a turbo car. What I am telling is a known fact. (Sorry you didn't know). Also, it is from experience. I was into turbo cars years ago and know the ins and outs. Trust me.