but didn’t you read the post by the guy with no performance testing and no credentials…he said they probably don’t work because his volvo intake manifold wasn’t that hot!
I’d need to know the volume of the manifold for the first one. Anyone want to fill theirs with water and check?
The second is too difficult to accurately calculate because surface area is a total unknown, hence why I suggest the best way forward would be to calculate exactly how much energy is being transferred (need mass and delta T measurements) and then apply that number to the mass of air and the heat capacity of air both of which are known.
So that’s my suggestion. I’ll fix a K-type thermocouple to the manifold (will try out a few different spots) and another to the head as close to the manifold as possible. We’ll do idle tests, running tests, and the rate at which the temperature of the head and manifold converge once the engine is turned off with no airflow through the manifold or over it.
Can we at least agree on the fact that whatever heating effect a warmer manifold has on the air, the effect will be largest at low rpm and smallest at high rpm?
And that whatever the delta T between the spacered manifold and the regular setup is, the change in air temperature will be only a fraction of that difference?
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Even if you know the rate of energy transfer while the engine is off it would be inaccurate, too many draws on the engine while running the heads cooling lines oil outside air inside air ambient conditions all play a factor while the engine is running even the amount humidity in the air could effect your results. You know as well as I know there is only one way to get an answer here that will hold any merit air temps before manifold and air temps after. The concept is simple. Not rocket science.
Even if you did get a result you would only have what the potential heat transfer could be to the air in the manifold with out the surface area you would have know proof of how they actually interact.
I don’t have any number results for the intake spacers but I can tell you this…
A while back when I was running the JHM tune and spacers I did the NYC RS4 run. After driving for about an hour and a half we all stopped at a check point, me and another RS4 owner opened our hoods side by side and felt each other’s IMs… mine was completely cold to the touch and his was warm/closer to hot.
It does make a significant difference in that aspect and I can’t imagine it not helping in engine performance.
Compared to so many things for this car it’s relatively cheap and almost a why not mod.
I’d just like to point out this wasn’t invented or used for the first time in our application.
FORD Racing sells a GT-40/Cobra Intake Manifold Phenolic Spacer Kit designed to reduce heat transference between the the upper and lower intake manifold to lower inlet air temperature to increase horsepower and allow for increased timing with less detonation. It’s been around since the late 80’s, still available to buy today…
I saw ArthurPE’s name above, brought back old memories…
Beyond Ford Racing, Trick Flow also sells them for the 5.0 crowd…
Lots of testing shown in MMFF back in the day. Great point I think this is just something the hard core guys that have really been around race cars for a long time know about and have already seen the testing. It’s been successful and successfully tested now for years. It’s almost like these guys that are new to the scene don’t know car history or modification history. You almost have a situation where the newer guys who don’t know cars or car history actually move backwards.
Everyone had a good weekend?
Because there’s more than one variable? If they posted full VCDS logs along with the rpm/second numbers maybe we would have something to analyze in depth. The differences are also quite small in absolute terms so I’d like to see data from a much greater number of pulls for statistical relevance. There is a margin of error and variability inherent in this type of testing.
I’d also like to know how the testing was done precisely. Did they heatsoak the car after each pull for a fixed amount of time or did they do them in very short succession? At high engine loads you’d be cooling down a hot manifold during the actual run because of the sheer amount of cool air going through it. Depending on how you test it performance could increase or decrease in subsequent runs!
An actual temperature probe on the manifold would also go a long way to understanding exactly what goes on.
[quote]I have already pointed this out…it’s because you’re an engineer. It’s in your nature to question things. Granted, however you need to wake up man…we’re talking about accelerating in our cars. For fun. We’re not building a bridge that will be used to transport yellow cake. There’s a point where you have to recognize that NO test is perfect and you need to use what is available to you.
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I am not an engineer, which I think I’ve pointed out before. I do question things, which is generally a good thing for the sake of understanding and making progress as far as I’m concerned.
[quote]Show me ANYWHERE that someone has said
a) there are ‘gains’
b) those ‘gains’ are substantial
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Well, I said that any ‘gains’ there were would not be substantial. This thread ensued. So I am assuming that people don’t agree with my statements which implies they do think your points a) and b) are true.
Furthermore, someone posted after this:
[quote]mine was completely cold to the touch and his was warm/closer to hot.
It does make a significant difference in that aspect and I can’t imagine it not helping in engine performance.
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That’s what I meant with intuitiveness being an issue in matters like these. Reality can be extremely counter-intuitive sometimes. That doesn’t mean that it is in this case, of course.
We need multiple measurements in multiple scenarios (some with the engine running, some not) to get a somewhat accurate idea of how much conduction goes on. It’s not going to be perfect, but a hell of a lot better than what we have right now.
We can do without the (impossible to calculate) surface area. We need to find out the conductivity, measure the actual delta T between head and manifold and log the amount of air going through the manifold.
The difference between expected temperature change and actual will show what is being transferred to the air. There’s nowhere else it can go in any big amount.
Even if the end result would be that spacers might be worthwhile after all, we’ll have a MUCH better understanding of the exact changes the air undergoes inside the manifold. If everyone kept following the contemporary line of thought without questioning we’d still be in caves.
it’s a comment on your mindset, not what it says on your business card. You’ve confirmed engineering was your education path in the past so I’m not sure why you say you aren’t.
[quote=JCViggen]Well, I said that any ‘gains’ there were would not be substantial. This thread ensued. So I am assuming that people don’t agree with my statements which implies they do think your points a) and b) are true.
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sorry…because people don’t agree with you that spacers ‘do nothing’ per your thesis, you assume the forum in general now believes the spacers make ‘gains’ and ‘substantial gains’ at that? Even though everyone has told you they bought these to prevent losses, as minor as that may be since they help? Your assumptions are pretty piss-poor. Try to pay attention when people are helping you.
I really don’t understand guys like this…I’ve said it half a dozen times already
NO ONE believes these add 20hp, but we know from actual experience with OUR cars that these spacers prevent a LOSS.
In my book preventing power loss is just as important as adding power, same reason guys upgrade cooling systems and intercoolers. No one ever said an upgraded intercooler will provide you 20hp, but it will help you lower IAT and either push a little more boost or prevent a loss from the higher IAT your old intercooler provided.
We aren’t telling you to buy these JC, we are simply disagreeing with you statement that these spacers “do nothing”…because it’s pretty obvious that is wrong.
I dont know half as much as some of the members on here. With that said after reading this thread i decided to hand touch my car friday night before the new IM and spacers went on. I drove 30 minutes in traffic to my buddies house. WAITED 30 mins with hood open to get engine as cool as possible to work on. EVEN AFTER leaving the hood open for half hour after driving i couldnt keep my kind on IM for more than 5 seconds.
Saturday i drove the car from my buddies house. I drove the piss out of it for 25 mins (love the new intake manifold pulls strong up top). I got home and popped the hood INSTANTLY touched it. I could keep my hand on the intake manifold and had NO NEED to pull my hand off of it.
So with that said, in my mind as others have stated. This probably doesnt net me shit. Maybe 3 or 4 hp. BUT this is me just thinking, when the engine becomes heat soaked and you loose power because of heat soak this would cause me to NOT LOSE AS MUCH HP which technically is giving me gains when the engine is heat soaked.
If im off tell me BUT you cant sit here and tell me they do nothing. That just doesnt make sense.
[quote=“sakimano,post:56,topic:7232”]
Where did I say that, good sir? I definitely said the effect was not zero. Just that has to be very small to the point that 250 bucks is a lot of money for the expected improvements over stock.
And for every example of someone selling phenolic spacers or a race car using them, there are many more which don’t use them. Most cars used in competitions don’t use phenolic spacers. Most manufacturers don’t use them either. Couple weeks ago I saw a relatively modern Ferrari engine in bits, nice big aluminium intake manifold and all. Nothing there to act as a heat barrier. It would cost Ferrari peanuts to include, or even make the manifold out of a different material if heat transfer to the air was an actual concern.
Heck, Aluminium is a poor design choice in general if you believe there is a significant amount of heat being transferred to the air to the point performance degrades. Still most cars both cheap and expensive use them. Some are using plastic (vastly superior heat transfer properties!) on their cheaper models and then fit an Aluminium one to the more expensive ones… shooting themselves in the foot supposedly.
Anyway, I’ve got a plane to catch. With some luck the stuff we need to gather data will be waiting for me in Belgium along with the car parts that have been piling up in my parents’ flat.
What formula are you planning on using? I can’t fathom how you would be able to tie any pertinent data results back to the manifold unless you actually use the the manifolds physical interaction with the air. Imagine I have a cube of aluminum and a sheet of aluminum I apply the exact same amount. Of energy to both the place both in a chamber of air the exact same amount of air. They will absorbe all the energy differently and releas it differently the air will again react Differently even tho they have the same mass. For you to say you can accurately predict how the air will react to the manifold with out knowing how it is physically interacting with the air you are a wizard.
As I have said multiple times there is only one way to make any pertinent measurememts. I have a b.s. BIS I switched from engineering physics. I was a physics major before that.
If you have the change in temperatures and an unknown and area also as an unknown your heat flux will equal be equal to your delta t over q which is a unit of area with out knowing one or the other your numbers prove nothing.
[quote=“JCviggen,post:59,topic:7232”]
aluminium? your manifold is made of aluminium? that must be a one off
Sorry the actual equation would have to be dQ*h= dA/deltaT where dQ is the thermal power given off by the engine, h is the transfer coefficient or how conductive the materials transfering the energy are dA is is the area of direct contact. If you don’t know either dA or delta you cannot have any conclusive results no matter how accurate your heat measurements are which for the record will be not very.