white2001s10

iTrader: (4)

I don't think you understood my post then.
Car A and car B both made 500hp because even though one had heads/intake, the CFM through the system did not change.
When car B tried to add 3 psi of boost to make more power it exceeded the physical CFM limit of the turbo.

Car A reached the physical CFM limit of the turbo when the boost was increased from 10psi to 12psi, then supplemented with N2O to go beyond the power limit... but still could not go beyond the CFM limit.
(note it takes less CFM for this boost increase with car A than it would for the same boost increase with car B)

Car B tried to do the same thing, but with the better flowing intake the turbo could not physically move the CFM to produce 10psi without becoming extremely inefficient in doing so. If car B had only increased boost to maybe 8psi it may have been able to effectively utilize 100% of the turbo's capability and should make more than 500hp. That is not what I cited in my examples though.

The original point is to discuss the results of improving intake efficiency with boost. I'm trying to do that by pointing out that it will be dependant on a few factors like the capacity of the turbo.

That means that in some cases it is definately not cost effective to improve the efficiency of the intake tract, and in other cases it is. I also pointed out that there are other (perhaps cheaper and better) ways to avoid spending the money on the improved intake, and also around the physical limit of the turbocharger.

The comment about blowing the engine up would apply equally to any of the scenarios and isn't really a factor in the discussion.

Quickin

Can't this discussion be summed up this way:

If you buy mods that improve flow, you need a bigger turbo or you need to make more boost with the existing turbo to accomodate that inreased CFM to make MORE POWER.....otherwise you're wasting your money and time?

I hope its that simple, otherwise I ain't learn'in ****



.

NemeSS

iTrader: (127)

a forced induction setup with correctly set up heads and cam,manifold,tb, WILL make a significant difference as opposed to a bone stock set up.it will make more power at the same observed positive manifold pressure.

white2001s10

iTrader: (4)

Unless that pressure is created by heat instead of increased CFM.

Got Me SOM

iTrader: (2)

wow this topic is beat up.

no doubt heads and a cam will more power, that's pretty obvious.

can we let this thread die now or put into the archives?

rjw

iTrader: (3)

The latest threads are referring to turbos.

I am attempting to squeeze the last few drops out of a MAG blower. I ran across this OLD thread and revived it a few days back, hoping to find others that have or have not had good results.

In my case the blower should pump 1000 CFM's or better. Most using this blower have decent power up to around 6k, but then only torque goes up.

I am looking at better heads (Darts at the moment) as well as TB and MAF options, that MAY get me to 600 rwhp.

At 500 to 550rwhp, the MAG is flowing less CFM and boost and heat are going up but power really isn't

A lot of the Ford guys are using a similar blower and getting more out of a smaller engine.

So, the thread is NOT a dead end, at least for me and maybe a few others.

I will conceed that we have beat most of it to death.

Pro Stock John

iTrader: (34)

Whites10 has too many variables going at once.

For sure better flowing heads and intake are a good thing, but many will not be looking for every ounce of horsepower from a given combo.

RW99

For me, I'd rather make my target power using less boost psi, so I'm using the AFR 225 for my PTK install. We'll see what happens. As PSJ states, I'm not trying to max out what the setup is capable of producing... I have a stock bottom end and will stop around 600/600. I want to make that power in the safest, most reliable fashion.

I'll post up with complete info when we're done with the car.

Rich

white2001s10

iTrader: (4)

The main point was/is that you can bolt on the better heads and intake and still dyno about the exact same as you did before the upgrade.
Upgrading the intake isn't as effective as some think. It can even work to the negative in some cases.

Adding the other variables (increased boost, bigger turbo, N2O) is just a reasonable quest for attaining that extra power that the upgraded heads/intake was supposed to produce. Most people would consider this after dynoing the same as before the upgrade.

I'm not sure why this subject seems to be so uncomfortable for some people. My posts weren't aimed at upsetting anyone, just bringing out more theories and facts.

Pro Stock John

iTrader: (34)

I'm not upset at all.

I guess it's time to roll out some opinions.

I see no downside in decreasing the amount of boost it takes to make say 750rwhp. After all, if it takes me 20 lbs of boost and C16 to hit 750rwhp unlocked, then hitting 750rwhp with 10 psi would mean I could probably just get away with 104 or even meth. I see that as a positive.

I see this as the 'heat game' because in the end we are only limited by the ability of a combo to make certain levels of boost, and our ability to keep that combo alive at high power levels.

Guys like W2W have done a lot of testing on stuff like this, and Kurt probably has some data on this. But suffice to say, a combo can max out the intake, and bam, you just create heat if you try to turn it up.

It's a given that I'd rather run 350cfm (@600) heads rather than 300cfm (@600) heads. I'd be running the best heads available that can work with stock intake angles. I'm sure the LS6 intake I have been using will be outstripped by a sheetmetal or a single plane set up for a 90mm, assuming that the outlet of the 'cooler is 4.00 and my piping is 4.00 as well.

white2001s10

iTrader: (4)

You are right that the intake temp goes down and this will be preferred by many.

One thing though is that when turbocharging and you drop the boost pressure, you still have the same exhaust volume and pressure to deal with, so cylinder filling can slow down. This could/does delay power at the lower RPM due to less pressure drop at the valve, and also cut into high RPM power by virture of the extra time factor it would then take to fill the cylinder with less pressure drop.

rjw

iTrader: (3)

My point is that if the heads or intake are restrictive and your power adder can't effectively by turned up all that much (like over 12 PSI). then the weakest links have to be addressed.

JMO, but how can I expect to flow 1000 CFM through a 75mm TB or MAF? Or through restrictive heads for that matter?

I hope that no one is upset. We are all just throwing ideas and opinions out..

In most Mag applications, people are still running stock TB and MAF. Some have gone to ported or larger, but I don't think 80mm is going to cut it, while 90mm may be overkill and MAY have adverse effects.

white2001s10

iTrader: (4)

The CFM between the turbo and the intake valve doesn't significantly increase with boost over what it was NA. The intake tract simply flows more mass which is what really counts anyway. This is why it doesn't matter so much the size of the TB, MAF, or intake port when running boost.

If you reach the physical CFM limit of your turbo, then it's still not going to help if you upgrade the heads or intake. The weak link would be the turbos capacity. I brought N2O into the discussion because it's one of the few ways you can get around this without swapping to a larger turbo.

rjw

iTrader: (3)

IF you noticed, I am talking DP SC, not turbo.

Turbos and Centris blow through the TB, and things are a little different.

Not to mention much higher PSI. At 100 PSI I could put 1000 CFM through a garden hose.

I am only going on my experience with Mags. I have personally seen good gains from headwork, and larger TB and MAF (sport compact app)

TeeKay

Start of sermon:

Let me throw a little Eaton S/C stuff in here. The PROPERLY SIZED Eaton can always flow more than the N/A engine can flow (overdrive pulleys). That's what makes the boost. If you hold pulley sizes (same blower cfm) and increase N/A flow capabilities of the engine (improve VE), then the boost, and along with it the temp of the intake charge, will drop. Your power will stay virtually the same. The engine can then require less octane for the same power or accept more timing for increased power. Period!

IC's stave off the heat effect, but don't stop boost "stacking" against a restrictive engine. IOW, a restrictive engine will not necessarily accept additional boost as more CFM/power (diminishing returns), it will just read higher on the gauge. Example: 12 psi and 400 hp, boost to 15psi and maybe 5% more power (numbers for discussion only). Example 2: Increase VE of engine and return the engine to 12 psi = 15% more power, or to 14 psi = maybe 20% more power. That's the way positive displacement (Rootes) blowers work. Trust me! lol

Now this shows that CFM is what makes power (you have to have the fuel too of course). Anything you can do to increase the CFM flow THROUGH an engine is going to increase power output. 1 cfm is = to about .75 hp. Just increasing the boost MAY do it, but maybe NOT (what I said before). It depends on the exact combo. This assumes that the components are reasonably matched and nothing is maxed out.

End of preaching - thanks for your time. LOL

So here's the drill (remember, you have to have the internals and fuel support to make this really work):
1. Put more boost in until you have to back off timing or increase octane to prevent detonation (KR). This assumes a good tune (priceless).
2. Increase the VE of the engine, heads, cam, whatever...
3. Raise/increase the boost back to or more than before. Then back to step 1!

HTH

white2001s10

iTrader: (4)

TeeKay,
I see some things that appear contradictory or I don't agree. If I'm wrong I'd love to have them clearly explained.

#1 To my understanding, requiring less octane and running more SA doesn't promise an increase in power over running a higher boost #. Take the example of NA (14.7psi), and a supercharged engine with 5psi of boost (19.7psi total). The NA engine can run with less octane and more SA, but that doesn't mean it will outpower the supercharged engine.

#2 You state that increasing the VE will lower temps and boost making the same power as before the increase in VE, which I think is correct. In your next paragraph you say that increasing the VE increases power by 15% which is quite a big difference.

#3 Also in para-2 your wording suggests that it is the restrictive engine that causes a dramatic increase in heat. My understanding is that heat increases very proportionately with the increase in pressure, but the dramatic temp increase comes when the compresser reaches a speed that will not effectively move more air. The beating or cavitating of the compressor creates a large amount of heat in the charge which then increases the pressure as seen on the boost gauge.

#4 My understanding is that the volume of air between the compressor and the intake valve does not change at all from NA, to boost, to more boost... only the mass is changing. The CFM past the intake valve can change however, but this points at the intake valve as the restriction instead of the rest of the intake tract as you suggested "restrictive engine".

#5 You say that a restrictive engine will not accept more boost as more CFM/power, suggesting that the mass moving past the intake valve will not increase with increased pressure differential. I think that is false. A good example is when you add a larger compresser to the same restrictive engine.
The larger unit will injest more CFM, and make a higher boost number without the excessive heat or cavitation problem that a smaller unit would've caused. In the process the higher boost will move more mass past the intake valve.

#6 In step-3 of your drill, in order to step the boost back up you must increase the speed (or size) of the compresser in order to injest more CFM. This is where I suggest that with an increase in speed, you may reach or exceed the physical limit of the compresser to move the air smoothly. If you exceed the limit, the temp would go up dramatically and you would get a power loss. Of course going the route of increasing the size of the compresser would avoid this problem and produce the additional output.

Perhaps the original compresser in question can handle the increased CFM without reaching its limit and adding the extra heat to the charge. In this case I say it makes more sense to simply increase the boost pressure from the start (step-1), and then skip step-2.

I hope I'm not being to hard-headed now. Please continue to discuss.

TeeKay

Well, this is gonna be long-winded - lol:
No. you're not being hard headed. I believe you're just not letting yourself go past the idea of a certain size intake valve as the limiting part of flow. So let's talk about it one at a time:
#1. re-read what I said. The boost drops due to better/higher VE. If that happens, the conditions I related also happen. Truth in testing over quite a variety of engines and years (i.e. I'm not just making this up).

#2. Again, careful reading will show that I said that *bringing the boost back to where it was before the change* will net the increase, not the change alone.

#3. Well, I can clarify that. A "restrictive" engine will require that you raise the boost and that in and of itself will raise intake charge temperature. The more restrictive the engine, the more pronounced the effect.

#4. I'd like to say this nicely, but your understanding is incorrect. The mass of the moving air changes with temp at a constant CFM. The volume (CFM) does change based on boost. That's what pressure ratio (of boost) tells us. PSI can (but might not) increase the volume (CFM) through the engine though. IOW, you can get the boost stacking I was talking about (psi increase, but very little CFM increase).

#5. That's not exactly what I said. And the intake valve size is not necessarily the limiting factor. I said that there is a point of diminishing return to just "turning up the boost". That limiting factor is the *overall* VE of the engine. My point was that you can reach a situation where all "turning up the boost" does is produce more heat and virtually no additional power.

#6. Your remark is dead-on correct. The point I was making is that *within the limits of the system* those conditions apply. If you "overmax" your system, then Houston, we have a problem! lol

The question (at the extreme of power) is not can the compressor handle the increased boost/CFM, but can the engine accept everything the compressor is capable of. There's a hundred examples of a turbo being too small to supply the engine it's feeding. Turn the coin over and you'll see what I'm driving at.

I hope that helps the discussion.

white2001s10

iTrader: (4)

need some time to digest when I'm more awake. Thank you for your time & reply!

Got Me SOM

iTrader: (2)

instead of doing the classic internet debate thing, why don't we do actual tests? when I get the money for the AFR's I'll be happy to report my results but that won't be for a few months. What sucks is my blower will be maxed out so I won't be able to run the same boost. T trim or YSi, hmmm hard decision.

Pro Stock John

iTrader: (34)

whites10 is basically advocating that folks not do ported heads because there is no value.

I think that position is a generalization, if you have some some of parameter like which fuel you are using.

I look at my combo, which has hit 17-21 psi, and run 9.4 with C16. I could probably get away with 110 leaded.

For me to run 8's at my current weight, with my setup, I would need to make more power. I'm better off in my opinion running a better set of heads and intake manifold than turning up the boost. I'd rather increase engine performance rather than find the limits of my fuel system.