|Bruce is well known for his "out of the box" and sometimes controversial thinking. In this article, he is experimenting with removal of the intercooler and replacing it with vaporization from a 7th injector. Time will tell if this works as planned ... for questions (or debates) please email Bruce directly. [-- editor]|
|Setting the Stage|
While reading Max Boost several weeks ago, I found some of his Intercooler statements very interesting. So much so, that I thought I'd do someexperimenting.
Disclaimer: When conducting automotive experiments, you should not conduct them without adult supervision. Remember they are for off-road use only. May negatively impact emissions. Melt down you engine. Do damage to your engine. When handing gasoline obey ALL safety measures.
This experiment is inherently dangerous, and the reader must assume all responsibility for their actions. When in doubt, further research is needed on the readers part. Never ASSUME, proper testing yields the correct results. This offering is just an alternative chain of thought and is an experiment.
Mr. Bell (author of Max Boost), mentions that locating an Intercooler, in the engine compartment is no location for an Intercooler, and there is what is called an interheater. An interheater is just the opposite of an intercooler, i.e. it puts heat into the charge air. With enough *marginal* or poor design features, some seemingly good ideas can run amuck
Locating an I/C in the engine compartment puts most all the transferred heat under the hood. There is a HP lose for the fan. The lack of vehicle speed can allow temps to escalate (MATs). The air cleaner being under hood is also no drawing in the heat that the I/C is trying to shed. So in some ways the stock I/C is self defeating. In the data logging I've done the true MAT seems to run about 40dF less then coolant temp., in the stock setup. Ambient temps will effect this to some degree.
A properly designed and **executed** I/C will generate more HP then a poorly designed and executed design. An Air to Air I/C needs air flow to cool the Charge Air. A *small* opening nose such as the GN dictates a large I/C to expose enough cooling area to the air flow. In the interest of space, I'm going to concentrate on the big picture. Once the car is under way, making boost and with not much airflow, the charge air starts putting heat into the I/C for a *time*, the piping and core start absorbing heat, and as the air flow across the I/C builds, it transfers heat away from the intercooler. Then as you let off the gas and airflow across the I/C drops (as a result of lower vehicle speed) the only heat transfer in the I/C is the charge air passing thru the I/C. 7 Gm/Sec of air flow isn't much, and that air is being consumed by the engine. So to some degree the I/C may just act as a flywheel for the heat put into the system.
For the purpose of this experiment I went with option #2.
What?. Take off the I/C?. The blasphemy!
Lets look at how a car may be used. While often GNs are Drag Raced and are only exposed to high boost conditions for 9-12 secs at a time, there is another element, whereby, a boost condition might last for several minutes, or just moments. Hmmm, so what can we do?
While without the I/C the MATs will want to jump at the first sign of boost, we might be able to minimize some of this. Suppose we use some chemical to absorb some of the turbo's heating of the charge air.
How can we do this?
One idea is lowering the manifold temp., using a fluid to absorb some of the heat. Then one side benefit is to also make the fuel as reactible as possible. One way to accomplish all of the above is with a 7th injector.
*** BUT, WITH A TWIST *** Let's let this one run *** FULL TIME ***
Yep, letting it run full time, allows for cooling the floor of the plenum (note mine is not stock). Any fluid that finds it's way into the plenum, must evaporate off of the plenum floor to then be pulled into an intake
runner. Then to allow the ecm to account for the **extra** fuel, we'll just adjust the injector constant.
Let's try using a 36 PPH injector. Now how to we do the math?. In my case I'm running 55 PPH injectors, and I added a 36, hmm, 36/6 is 6. Increasing the 55 injector constant to 61 takes care of the *extra* fuel. Is it perfect?, NO, is it close enough, YES. Not only yes, but very much so.
In review, we got rid of the extra tract length, and volume. We lessened the preheating of the manifold when at low vehicle speeds. We preheated SOME of the fuel, into a vapor which REALLY reacts reacts well. We actually lowered the manifold temp some. We decreased the time for the intake tract to recover to *normal* temp. after a high boost condition. Got rid of the crank fan. Got rid of a few pounds of weight. No longer have the pressure drop across the I/C.
For those that dare, if you use an ATR 7th injector as pictured here, you can wire it all up as normal, AFTER you take the control box apart and bypass the Hobbs switch (cut the leads off and solder together). Then plug the hole where the Hobbs Switch was. I'd advise making the box water resistant.
While it's easy to do the math on charge temps., and how they effect HP, the issues go deeper then that. It's the big picture that counts. The pictures show the experiment as it sits at the time of writing. This plumbing was just meant to test the principle, and see if it was worth pursing. Things will be now redone in a more permanent manner, and some code changes to further optimize this experiment.