Getting ready for Bonneville(rebuild)

[jl222]

That car is looking amazing! I would only change one thing...move the water nozzles to the compressor DISCHARGE. The compressor housing will sling the water to the walls and condensate. It will also give more mass to excellerate, making the compressor less efficient. You might even see EGTs drop by moving it downstream of the blower. 

   Thanks....we have run 36lbs of boost at Bville which is more like 38 lbs because you start out with less atm psi, thats close to 400 deg on a 90 deg day with 75% compressor efficiency. the water will evaporate at 400 deg + cool the blower. Any drop in inlet temp will result in less egts.
    The owner of Alcohol Injection Systems has also seen an increase in boost in his blown mustang drag car of 11/2 lbs [at 15 lbs boost ]from injecting into the intake which he believes might be from making a better seal. All the WW2 aero engines that used water injection injected into the intake.
   We are installing a new data recording system this week that will record blower temp and pressure before and after the intercooler
and after the water injection nozzels on the discharge pipe after the intercooler. Also installing 8 egts.
   Then we tune on the dyno with and without water injection, then we should have a lot more info.


                            JL222

                   

[Boostedballs]

Wow, 400F, that's some serious heat! I get scared when I see anything over 200F in my car. Mine would go into meltdown at that temp for sure.
The WWII aircraft did inject upstream of the blower but I think it's because they used boost pressure to move the water; also, less parts (like a pump) to break down over enemy ground.
Hot air means higher velocity through the compressor and less drag. The water injection will alter the flow map, that may be why the owner of AIS sees higher boost with it.

So you are spraying in the compressor and after the intercooler? It might be worthwhile to weld in some more bungs downstream of the intercooler and move the nozzles from the compressor inlet so you can have a good comparison. I really think you will have water condensating into larger droplets inside the intercooler if you don't. I know, 400F is way hot, but 38lbs is working against the ability to evaporate the water. Water boils at 212F at 14.7psi. You are at 50psi actual; which brings the boiling point of water to 350F. I know it's an H2O / methanol mix but the same theory applies. So, even at 400F, you need the smallest water droplets you can get. As the temp comes down, the evaporation rate is further reduced.
For instance, a drawthrough turbo system will use larger carb jetting than a comparable blowthrough system because the compressor de-atomizes the mix.

I can't wait to see the EGT results; I hope they are even across the 8 ports.

Keep it going, I'll be looking forward to seeing it run again soon!

[jl222]

  Boostedballs...Don't worry our engine never sees that temp, that's why we have that big intercooler,air comes out at 60----140 deg and water injection after the intercooler is meant to get in on the compression stroke as the air is already cooled.
  I don't how you come up with 50 lbs but 400 deg at 38 lbs boost on a 90 deg day is over 75 % efficient [which is very good].
  The tractor pullers have been blowing your theory of non-evaporation at high boost for years, how about 250 lbs boost water injected at 3 gal min and no intercoolers.
  That's why WW2 aero engines used centrifugal super chargers...intercoolers and water injection.

               JL222

[saltfever]

    I don't how you come up with 50 lbs but 400 deg at 38 lbs boost on a 90 deg day is over 75 % efficient [which is very good].

14.7 (seal level) plus 38 psi (your boost) = an absolute pressure of aproximately 50+ psi.

[bvillercr]

The engine doesn't see absolute, actual is 38psi.

[jl222]

 I guess the [absolute] correct way to talk about boost is pressure ratio, atmosphere psi + boost divided by atmosphere psi

 sea level 14.7 + 36 divided by 14.7=3.45 pr.---  Bville on one of our time slips 25.72 inchs or 12.66 lbs
 
 12.66 +36 divided by 12.66=3.84 pr

 Its easier to just talk boost though

        JL222

           

   

[desotoman]

The engine doesn't see absolute, actual is 38psi.

Are you sure?

Tom G.

[willieworld]

tom if you will be at el mirage i will bring you some parts                       willie buchta

[bvillercr]

The engine doesn't see absolute, actual is 38psi.

Are you sure?

Tom G.

Well... Yes and no. . All engines see that first atmosphere so yes it does count, but most don't include it when talking about how much pressure they are spinning into the boosted engine.  So I was incorrect in my wording......kinda. :-P

[saltfever]

I thought you converted to EFI. Your EFI fuel map includes MAP. (Manifold Absolute Pressure).   But I like your use of pressure ratio. It provides a quick comparision of how much heat is produced by adiabatic compression which your intercooler is taking care of.  

[Dynoroom]

Ya gotta just love tunning to all those kPa's.....   

[jl222]

I thought you converted to EFI. Your EFI fuel map includes MAP. (Manifold Absolute Pressure).   But I like your use of pressure ratio. It provides a quick comparision of how much heat is produced by adiabatic compression which your intercooler is taking care of.  

  I have a chart showing boost from 2 ---100 lbs and different compressure efficiencys that i use, a friend of mine and I made up a program for my computer around 1992, I new the formula and she new how to put the formula into the computer, it was pretty cool
because I could change the temps and ambiant pressure and it would bring up the temp, but I lost the program when the new computer
wouldn't take the older style program.

  I'll see if Troy can take a foto of the charts and post it here.

                       JL222

[desotoman]

I thought you converted to EFI. Your EFI fuel map includes MAP. (Manifold Absolute Pressure).   But I like your use of pressure ratio. It provides a quick comparision of how much heat is produced by adiabatic compression which your intercooler is taking care of.  

  I have a chart showing boost from 2 ---100 lbs and different compressure efficiencys that i use, a friend of mine and I made up a program for my computer around 1992, I new the formula and she new how to put the formula into the computer, it was pretty cool
because I could change the temps and ambiant pressure and it would bring up the temp, but I lost the program when the new computer
wouldn't take the older style program.

  I'll see if Troy can take a foto of the charts and post it here.

                       JL222

John,

You can just use this site for your calculations. IMO much easier than a chart. Just plug in your numbers and presto.

Tom G.


http://www.stealth316.com/2-turbotemp.htm

[jl222]

  

 That's really great Tom could you post that link under the supercharging post under [technical] I bumped it to the top
from pg 4 so you could find it.
 The best part is the numbers on my chart that I checked [ 14.7 atm.---30 lbs boost ---70 deg day and 75% efficiency
came up exactly  331 deg
  Just put it on my favorites [THANKS]
             JL222

[desotoman]

Hi John,

Your welcome. Thought you would like it.  I posted it in the other thread.

Tom G.