thejulex

There is a thread on audizine.com in S4 (B5) forums about the spacers with some logs I believe. The bottom line is that, again, this is "less power loss" mod that helps the most in extreme situations like on a track and with meth.

Worth it? Probably. Even if it lower temps by a mere 10f, that's still a lot. Compare that to a set of ER ICs for $1000+ that lower temps by what? 10-20f? In that respect, phenolic spacers are much bigger bang for a buck!

Flyboy

Have you got a link to that AZ thread? I searched the site for phenolic spacer and came up empty on a discussion of testing the product.

Do you have any proof that they work better on a track? What does methanol injection have to do with phenolic spacers?

So, do you really think that ER IC's lower the charge temperature 10F? Any guess what the charge temperature is at the compressor outlet, prior to the IC's lowering that temperature?

I'm not going to say that they absolutely don't work, since I don't as of yet have solid proof to point to. All the same, I've never seen anything that would convince me that they are all that worthwhile.

hans j

On a B6 1.8T...
https://www.audiworld.com/forums/sho....php?t=2341484

Power gasket manufacturer info...
http://www.newsouthperformance.com/gasket.htm

I'm still on stock intercoolers as well as turbos so I can't say either way. I have run mine at track temps and they hold up fine, but since everyday is a new day, I can't tell you whether it is faster or slower. Sure it might be minimal gain but I wanted to see how well I could make them myself and didn't really care to buy someone elses. I researched all the plastics out there and that is the only hard fact information I can provide.

Flyboy

Thanks for the links, always interesting to see users results.

My first thoughts on the test results are that he did not drive the car long enough. I find that it does take a while for my car to really heat up, I'm guessing the oil temps would barely begin to register in that short of a period of time. Also, like he mentioned, the IAT sensor is located near the front of the intake manifold so it is unlikely to show any difference. I wonder if having a V6 versus 4-cyl would also come into play, more surface of the intake manifold in contact with the engine.

Also, assuming the cross section of the intake manifold is approximately 3 inches in diameter, and the air travels a foot inside the manifold, at a mass flow rate of 150 g/s the air is going to be inside the manifold one or two hundredths of a second, not a whole lot of time to absorb heat from the manifold walls.

hans j

I gave one to a coworker yesterday (2001 1.8T) and he checked the temp before and after with the same heat gun. He measured 95*C at the injector boss and 65*C at the throttle body. After the gasket he was measuring about 60*C at the injector and 30*C at the throttle body.

It's true that the air isn't in there long but it still comes in contact with a hot manifold. Reducing under hood temps is also a big gain to be had. He said power was about the same but felt more snappy and felt a little more torque.

And really a car should be totally warmed up within 10 minutes. If your oil temp is rising with your coolant temp, you have a bad thermostat and the car won't warm up as fast.

thejulex

What one needs to realize with the spacers is that they don't necessarily work the best in WOT situations, on contrary, they provide most benefit in situation where the charge is moving relatively slow and has time to pick up heat from hot metal. At WOT, the amount of air entering the manifold is so large that this alone cools the manifold considerably.

This can be seen when driving around and logging IATs. Idling/part throttle IATs are usually pretty high while stepping on the gas immediately causes the IAT sensor to register much lower since more air is entering engine and it doesn't have time to pick up heat from all the various components on its way to manifold. It does eventually pick up (naturally) once the turbos kick in but the effect is pretty obvious pre-WOT.

The true test would therefore consist of driving the car on the exact same route, in the exact same manner and at the same ambient temps and measuring the temps on top of manifold.

The fact is that the spacer must help, at least at the manifold itself and to reap full benefit of the mod you need to do couple more things... most notably wrap all intake tubes in insulation, buy good ICs, get meth, etc.

hans j

But the air sensors are open element, just a little wire hanging out in the air stream. So even though the IAT temp go down, the manifold doesn't cool off. It can get hotter because under hood temps rise and head temp rises.

I do agree with checking it with a consistent driving pattern, but even then air temp usually fluctuates daily. Best bet is to drive in winter only

Flyboy

Here's another estimate, at idle the MAF reads 5 g/s, going back to my estimate of the pathway in the manifold being about 3" diameter and 6" in length, the velocity of the air at idle is around 18 ft/sec through a 3" tube. So in that case the air would be in that 6" tube for ~0.03 seconds. Those numbers are ballpark, but you should wonder how much of a difference an intake manifold 20, 30, or 40F cooler is going to make on air that is in contact with it for three hundredths of a second.

Whether you wrap your entire intake system in insulation, have the best IC's going, and have a WI system going as well, none are going to change what the intake spacers do. How do any of those parts enable the phenolic spacers to perform to their maximum?

donromani

here's my take on the phenolics: not worth it as a mod on their own because taking the mani off is such a hassle and the benefits are marginal at best. However, I would definately toss in a set of the 5mm at least if I was going stage 3 or had the mani off for some other reason, like replacing that pump.

I put mine in when I did the RS6 build. Not difficult, extra 2 minutes install time, and not expensive either. Do I feel a difference, yeah.....but I think the RS6 turbos have more to do with that haha

my 2cents

Flyboy

data to the contrary my conclusion stands.

http://www.myaudis4.com/images/mods/phenolic/pst.htm