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building an NA that could

You’re going to be short of your HP goal if using a stock intake manifold. That’s the real bottle neck on a 8v NA volvo.
Kyle (klr142) has built up and raced some very hot NA 8v engines for road racing (~170-180 crank hp), and you can find some of his stuff linked here:
https://forums.tbforums.com/showthread.php?t=354499

http://forums.turbobricks.com/showthread.php?t=349780

http://forums.turbobricks.com/showthread.php?t=221925&page=4



He’s currently running some cam that’s a bit larger than the T5 cam, and it’ll be interesting to see how it does compared to the “small” cam he had in there previously.

Kyle really seems to know his stuff! verry informative post thnx.

Is it the name that makes you lose faith in my thoughts?:lol: I've got a little surprise for you regarding the intake manifold but more on that later ;-)
 
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Here you go, Some long waited for progress pictures :oogle:

Screenshot_20200622-160922_Gallery.jpg


Seats are ground and valves cut. On this picture shows some minor porting in progress. Head is currently cleaned and waiting to be milled roughly 2.5-3.0mm.

Screenshot_20200622-160957_Gallery.jpg


Some structure paint on there so after milling it's ready to get the head finished up.
Was thinking of getting the dynamic cr to something like 9:1 for pump gas, Suggestions?
 
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Kyle really seems to know his stuff! verry informative post thnx.

Is it the name that makes you lose faith in my thoughts?:lol: I've got a little surprise for you regarding the intake manifold but more on that later ;-)

Not the name. Mostly that 1% of proposed ITBs or motorcylce carbs actually get finished (completely made up figure, but it seems that way)

Some structure paint on there so after milling it's ready to get the head finished up.
Was thinking of getting the dynamic cr to something like 9:1 for pump gas, Suggestions?

That's in the ball park of what you want. Will probably want a bit more depending on cam and how it's being driven, especially if using a stock intake manifold. If using ITBs and running high revs, you might want a bit lower.
Interesting thing is, you can alter the intake valve closing by lash or by adv/retarding the camshaft.
 
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I'm running a high compression B23 with an H cam and Stahl header connected to a 2 1/2" madrel exhaust. Feels about as fast as my stock 242 GLTi. I would presume that you would be about the same with an 2.2 841 computer.

It does like to sing though. I had to switch to blue top injectors out of a 460 ford to keep the AFR at 12:1 above 3000 rpm. Peaks at 12.6 or so by the time I hit fuel cut at 5500 RPM. I'm running LH2. Once you hit 3000 RPM, it just switches the injectors from pulse to hold open and ignores the O2 sensor feedback.

I'm running a round tooth conversion with a Nuke cam gear. I adjusted the cam gear till I got some ping on full load, full throttle and backed it off a degree. Resulted in a 2 deg advance with this setup.
 
Thnx, I think i'll stay close to the 8,5:1 DCR For the people interested i found a great article with usable examples that isn't a v8:lol: Since the spec's aren't known regarding intake valve closing time i decided to use a fairly similar grind from catcams. I'll be mailing KL asking for accurate data. Here is my input on the Wallace racing dynamic compression calculator.

Knipsel.PNG





A small technical article for our petrol heads fans understanding Dynamic compression ratio.

Building a performance motor, one of your first thoughts was probably 'How high should my Compression Ratio (C/R) be?" If so, you need to know the difference between Static Compression and Dynamic Compression, as Static compression is meaningless in itself.

First, lets talk about the two types of compression ratios, Static (SCR) and Dynamic (DCR), and their differences. When most people talk about compression ratio's they are referring to an engines Static compression ratio. The Static ratio is a simple concept and represents the ratio of the swept volume of the cylinder (displacement) to the volume above the piston at top dead center (TDC).

For example, if a hypothetical cylinder (evo 4g63) had a displacement of 500cc and a 50cc combustion chamber, the CR would be 550/50 (500+50/50), or 11:1. If we were to mill the head so that the volume above the piston crown was decreased to 40cc, the CR would now be 540/40 (500+40/40), or 13.5:1. Conversely, if we hogged the chamber out to 60cc, the CR would now be 560/60, or 9.33:1. Using these examples, it is easy to see how slight changes to the chamber volume dramatically effect the Static compression ratio, as well as the Dynamic compression ratio.

Everyone knows that high performance engines typically have higher compression ratios. Why, because higher compression ratios make more hp. Higher CR's also improve fuel efficiency and throttle response. However, there are drawbacks to bumping the C/R to high. Simply put, once the CR exceeds a certain point, detonation occurs. Detonation kills power and it kills the engine, literally.

The amount of compression a given engine can handle is determined by many factors. These include combustion chamber design, cylinder head material, the use of combustion chamber coatings, and so on. Once these mechanical aspects of the engine have been fixed, the main variable is the octane of the fuel used. Higher octane fuels offer increased resistance to detonation, or the ability to tolerate more compression. However, there is a draw back, higher octane fuels cost more money but are built for racing purposes.

With that in mind, you are probably wondering, how high should your C/R be? Even if you know all about your engine and have decided what octane fuel you are going to use, the question cannot be answered as phrased. Why? Because without reference to the camshaft specs (where the intake closes), talking about the Static compression ratio is useless.

How is this so? Well, think about how a four stroke engine works. The power stroke has been completed and the piston is heading upwards in the cylinder. The intake valve is closed and the exhaust valve is open. As the piston rises it is helping to push the spent combustion gasses out the exhaust port. As the piston reaches TDC and starts back down, the exhaust valve closes and the intake valve opens. Fresh fuel and air are drawn into the cylinder as the piston reaches bottom dead center (BDC) and starts back up. This is the critical point as far as understanding the Dynamic compression ratio (DCR).

As with all cam profiles, the intake valve is still open after BDC, and remains open as the piston begins its path upward. Consequently, even though the piston is rising upwards in the cylinder, compression does not actually begin until the intake valve closes (IVC). Once the intake valve closes, and only then, will the air fuel mixture begin to compress (DCR). Hence, the ratio of the cylinder volume when the intake valve closes, over the volume above the piston at TDC, represents the Dynamic compression ratio. The Dynamic CR is what the air fuel mixture actually "sees" and it is what "counts", not the Static CR. Because DCR is dependent upon the IVC, the cam specs have as much effect on the DCR as do the mechanical specifications of the motor.

It should also be noted that the DCR is always lower than the SCR. Most performance street and street/performance motors, with a typical performance camshaft and a SCR of 10.0-12.0:1, will have a DCR in the range of 8.0:1 to 8.5:1. Any higher may result in detonation problems with pump gas.

Dynamic compression ratio should not to be confused with cylinder pressure. Cylinder pressures change almost continuously due to many factors including RPM, intake manifold design, head port volume and efficiency, overlap, exhaust design, valve timing, throttle position, and a number of other factors. DCR is derived from measured or calculated values that are the actual dimensions of the engine. Therefore, unless variable cam timing is used, just like the static compression ratio, the Dynamic Compression Ratio, is fixed when the engine is built and never changes during the operation of the engine.

It is known that most gas engines make the best power with a DCR between 7.5 and 8.5 on 91 or better octane. A 2000cc 4g63 evo engine with a 9:1 static CR using a 246deg cam has an intake closing point of 52? after BDC and produces a DCR of 7.93. Same engine with a 286 cam (having an intake closing point of 72? ABDC) has a DCR of 6.87, over a full ratio lower.

Hence the larger cam's DCR falls outside the acceptable range. It would have markedly less torque at lower RPM, primarily due to low cylinder pressures, and a substantial amount of reversion back into the intake track. Higher RPM power would be down also since the engine would not be able to fully utilize the extra A/F mixture provided by the ramming effect of the late intake closing. To bring the 286 cam's DCR up to the desirable 7.5 to 8.5:1 for a street engine, the SCR needs to be raised to around 10:1 to 11.25:1.

This lowering of the compression ratio, due to the late closing of the intake valve, is the primary reason cam manufactures specify a higher static compression ratio for their larger cams: to get the running or dynamic CR into the proper range.

Unless you have actually measured the engine (CC'd the chambers and pistons in the bores), these calculations are estimations, at best. Treat them as such. The published volumes for heads and pistons can, and do, vary (crankshafts and rods, too). It is best to error on the low side. When contemplating an engine with an 8.4 DCR or higher, the measurements are essential, or you could be building another motor.

Using this information, DCR is only a tool among others, that a builder has available. It is not the "end all" in cam or CR selection. However, the information provided is very useful for helping to match a cam to an engine or an engine to a cam. It is still necessary to match all the components in an engine and chassis for the best performance possible. Pairing a 286? cam with milled log head just won't cut it even if the DCR is correct, as the cylinder head will never support the RPM capabilities of the cam.

Alternatively, with the SCR known, manipulate the cam specs until a desirable DCR is found. When the best intake closing time is derived, look for a cam an intake closing timing, that provides the other attributes desired (lobe center and duration). Often times the best cam is smaller than one might expect. Sometimes a CR change is needed to run a cam with the desired attributes.

The information given here should be used as a guideline only. There are no hard and fast rules. It is up to you, the engine builder, to determine the correct build of your engine. And remember, unless accurate measurements are taken, calculations are only approximations.

We won't go into all the calculations required, as there are numerous programs available for handling that chore. We recommend purchasing one of these programs, if you are going to select the camshaft profile, and CR without the assistance of a trained professional. We are more than happy to assist you in selecting a cam profile if your not sure. You can send the information to us and we will run the numbers for you.

To determine the Static compression ratio, you need the following information. Cylinder bore, crankshaft stroke, head gasket bore and thickness, piston dish size (if any), deck clearance, and cylinder head chamber size. To determine the Dynamic compression ratio, you'll also need to know the intake valve timing (when it closes).

The ideal DCR range for a performance motor on pump gas is 7.5 to 8.5
Now, lets build a 2000cc engine that is used as a daily driver. As such, we prefer good economy with low to mid range performance, using low octane fuel. Were also concerned about building the motor within a budget. Since we are concerned about economy, we will be using the stock dished pistons if possible. we'll stay with dished pistons to optimize our mileage, and zero deck the block for better quench characteristic and a bit more compression.

Next, using the cam specs, we'll select a short duration cam profile as they work best for low compression motors (for economy). But not to short as we also want one that allows more mid range performance for a little more get up and go. Looking at the specs, our best choice would be the 260 / 256 stock cam. But do we go with a 112 or a 110 lobe center as stock? A 112 lobe center has the intake closing at 62 degrees and offers a smoother idle, while the 110 lobe center closes at 60 degrees and offers more low end grunt and a little bit of a lope. So which do we use?

This is where the dynamic compression ratio comes into play. Since we are building a mild performance motor, the chart will give us a pretty good idea. However, if we were building a high performance motor I would recommend purchasing a Cam Utility program for calculating precise numbers, rather than using approximations.

With our sample motor, we want to use the chart for dished pistons, with a .020 over bore, and zero deck height. Since we are building a motor for the best possible economy, and want to use low octane gas, we need to stay in the green ranges, or around 7.3 to 7.5 for the best performance. But wait, what about chamber size? We know our stock head has 47cc chambers, but looking at the chart, we see that the chambers are to big for the cam profile we selected. With the intake closing at 62 or 60 degrees (depending on the lobe center) and 47cc chambers, our DCR will be to low for good performance.

No problem. Lets move up the charts, looking for a chamber size that has the correct DCR and valve timing for the cam profile we selected. Remember, less static compression is better for an economy build, and that you want to leave as much meat on the cylinder head as possible, leaving room for another rebuild down the road. Therefore you want to find the first match with the IVC (intake closing) between 60-65 degrees, and the DCR in the 7-3 to 7.5 range.

Here is the recommendation and ideal DCR range vs octane

Regular pump 87-91 octane : 7.0 - 8.4 DCR
Premium gas 91-93 octane : 8.4 - 9.1 DCR

12091299_967162536655207_4189843893619699733_o.jpg


For further questions or tech tips please send us email.
infos@extreme-tuners.com / tech@extreme-tuners.com

Spyros Panopoulos
 
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The plan is to use GSXR-1000 throttle bodies with some sort of cheap megasquirt knockoff. Just finished cutting the head and installing the valves. the head is finished and cc'd out at 41.

For calculating the compression ratio:


530 Head stock: 51.7cc
530 Head shaved: 41cc
gasket (1.2mm): 8cc
piston dome: 6cc
displacement: 579cc

Stock:
51.7+8+6=65.7

65.7+579=644.7

644.7/65.7=9.81

Shaved:
41+8+6=55

55+579=634

634/55=11.52

So it already gets quite close to that desired 12:1 compression ratio. I'll shave the block roughly 0.25 mm. That should result in a nice piston to head distance (<1mm) and bump the compression to roughly 11.9:1. Been thinking about something else. There is a general rule that for every 1000 rpm there should be at least 0.004'' (0.1mm) clearance to compensate for rod stretch. So if an engine would rev to 8K it'll have enough stretch to seriously increase compression. Is this compensated by the fact that after peak torque you wont get a 100% fill so it gets away with the higher compression or am i mistaken something here?

20200624_081229.jpg
 
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I remember threads about the 'tight squish' where that kind of thing was discussed. If I recall correctly that had to be accounted for with a much higher than stock engine red line.
 
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As the piston rises toward TDC, the rod is actually under compression, so that's not a concern. Also, I'm not sure how much a steel rod actually stretches at these power levels, piston weights, and RPM. Somebody wanna do the math on this?
 
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My first Google can't up with this article on inertia, the 608g pistons in my build add up to 2986lbs on the exhaust up stroke at 6250 RPMs, I don't think I'll be running the engine past that after finding that little tidbit out.

https://www.google.com/amp/s/blog.k1technologies.com/stoker-crank-science-piston-speed-rod-angle-explained%3fhs_amp=true

I'm here to burst your bubble and say that equation is grossly simplified.
I'll see if I can dig up the actual piston position vs crank angle equation... I have it somewhere...

It's up to you to find the acceleration, and then the forces from that :)
 
Big edit:

As the piston rises toward TDC, the rod is actually under compression, so that's not a concern. Also, I'm not sure how much a steel rod actually stretches at these power levels, piston weights, and RPM. Somebody wanna do the math on this?


Thought a lot about my own noob question but here is what i think, During the compression stroke the cylinder is also filled with mixture that starts burning before tdc, So there is always pressure above the piston that keeps the rod from stretching. During the exhaust stoke there is nothing (pressure, force) left above there to keep it from stretching. Thus should be having no effect on the compression ratio.

I'll start to weight and match the pistons and rods soon. It'll be stock pistons with 13mm rods from a turdbo :oogle:
 
I am apparently very late to this party. What is the current state of this engine? Did you have the block shaved already? Did you first measure your piston to deck height? I'd much rather just use a thinner Cometic gasket than shave the block because I know for certain what the compressed thickness is and you retain full block strength(not really an issue I guess, hah).

13mm rods from a turbo are the same as 13mm rods from a non-turbo.

Did you hear back from KL Racing about intake valve openings or anything else that might make it's advertised numbers more relatable to something else? Robert, can you send one of yours to Shoestring for measuring, pretty please? :)

A 41cc chamber sounds pretty small to me but with a stock b230F bottom end and stock headgasket, if you have pistons that sit(sat) about .010"(roughly .254mm) above deck and took off .25mm, you around roughly 12.1:1 static compression with an assumed 6cc piston dish and stock headgasket. That leaves you with .027"/.686mm of piston to cylinder head clearance assuming the headgasket used is definitely .047"/1.194mm thickness compressed. That is a bit tighter than Erland Cox recommends on his motors(.031-.040"/0.8-1mm), but he revs them higher than 7000 and 8000rpm(sometimes 8500rpm). (Your dynamic compression calculation on the previous page shows you have an 86mm crank instead of the 80mm one?? - If so, that's actually 12.9:1 static compression with 41cc chambers, not the 12:1 you entered for your DCR calculation...)

On our current engine in the General Leif, one of the pistons seemed to be about .011" proud of the deck(while one of the others was somehow only .007") and we are using a .036" Cometic MLS gasket. It's somewhere around 11.3-11.7:1 with our 42/43cc chambers at the moment(3mm or so off a 405 head with very opened up chambers). So far it's rev'd to 7200rpm without an issue, but it's tighter clearance than we wanted.

Recently Erland suggested to me that the KL Racing S/T5 camshaft is ok for about 190hp where the ENEM C2 camshaft is good for at least another 20hp more. We're running what I think is a copy of a C2 camshaft at the moment. We haven't been back to the dyno yet, but it moves pretty damn well for what it is when coupled with the close ratio gearbox, 4.56 rear end and short tires.

https://youtu.be/0NkHMPvR4wY?t=760

He also recommended 3mm off the head, 13:1+ static compression and 16-17+ cranking compression(240-260psi!) with this C2 camshaft(I assume) and Europe’s 98 Ron octane(like 95 or so for us in the US). We have another B230 with squirters in the garage waiting for some time and money to slap some 97mm flat topped pistons in it. On that one I think we'll shoot for closer to 12.5:1 or so static with the same camshaft. Right now we are not detonation limited for maximum brake torque and are running around 4 degrees less ignition advance than stock at WOT, approximately(just under 30?). I have attached a picture of the head below for reference. Erland said " I take a little less towards the plug side of the exhaust and I don’t use Singh grooves." when I showed him a picture of our chamber.
 

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Kyle, Good to hear from one of the NA guys!

I've actually bougt a set of forged rods and cleaned a bottom end and pistons that came from a good engine. Kind of ashamed to tell how the engine got together instead... Here we go:lol:. The car we bought had a b230FB in it, And that's also where the 531 came from. When we first removed a plug and took a look inside with the endoscope the cylinders looked a bit "dirty"but it was clear that it's a low mileage engine. Being that it has the squirters and thick rods we decided to pull the head and if usable just slap the head on there and give it a go. The dirty look was because someone decided to do some port matching on the intake side only but apparently forgot to clean the head after. There were quite a lot of debits left over in the bores so it's a good thing the po had never ran it this way. The bores cleaned up nice and it seems like a good place to start form to get moving under it's own power. so .. Stock bottom end, Like bone stock. The 530cc'd out at 41cc's i'm 100 percent sure of this. It has been milled quite a lot and has flat top oversized valves in it. I'll run the compression calculation again, Thanks for pointing me on that error. Unfortunately i didn't get any info out of KL, Guess i'll try it again tomorrow.

It doesn't look good for my 200hp target to be honest. Maybe i'll build another engine with the 531 the right way that was intended in the first place
 
Is it possible that you put a two pieces of Fajs 50mm dual carbs to it.
Here in finland we have a good experiences about those china carbs.

in 200hp goal i wouldn't go any smaller than 50mm.
I know a person here, which runs a speed shop, he has made my head.
He had a cnc machine, dyno and a flowbench. He has measured that even 48mm carbs are restriction espesially if good intake are used (that kinda intake that does not restrict flow).

HE uses a sheetmetal intakes which is build by himself.

25182372_10215738911573593_847962302930404723_o.jpg
 
HEre is a flow bench numbers at 530 head which he had build.
Not many people get those kind of numbers even with a 531 head.
23157331_10215396051242299_7476493032028783924_o.jpg


235cfm at 530 head is very very good.
My head does not flow like this because it's ported to make a large register and good torque at 3500-7200rpm
My head flows something about 210-220cfm, i can't remember and i have flowbench raport somewhere that i can't found it.

But my point is that porting is very important in na-power and porting without a flowbench or a ton of experiences you could easily make your head flows less with so called "random-porting".

Also, combustion chamber shape is important. Here is a picture about my head's combustion chamber, which is made for forced induction.

vDc0sK


Here is 220cfm intake channel:

 
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That's one awesome head! What kind of cam does he use in it and how much power does it make?
I just wish i put some more work in the exhaust ports.. Intake will be alright for this power level. If it doesn't make the power we wanted we'll pull the head again, Do some more to the exhaust ports, change to a thinner head gasket and swap in something slightly more radical of a cam

About the induction size i think you're wrong.. 50mm carb's usually have a 40 maybe 44 mm choke so i figure 46mm throttle blades without choke shouldn't be a restriction at all :oogle:
 
That's one awesome head! What kind of cam does he use in it and how much power does it make?
I just wish i put some more work in the exhaust ports.. Intake will be alright for this power level. If it doesn't make the power we wanted we'll pull the head again, Do some more to the exhaust ports, change to a thinner head gasket and swap in something slightly more radical of a cam

About the induction size i think you're wrong.. 50mm carb's usually have a 40 maybe 44 mm choke so i figure 46mm throttle blades without choke shouldn't be a restriction at all :oogle:


He makes group-f rallycar engines, which usually uses camshafts about 280 *0.050, and something about 14-15mm lift, today he called me and tell that last motor he was built produces about 260hp and pulls to 8000rpm without significant power loss. (2,3liter b230)
 
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