inactiveuser1

Forgot which post I found the picture on but this would be one way to tie in.
2 Eram without blocking the system or 4 all together time to get Mark going on this:-)
Anyone know if John's air intake up front is replaceing the front snouts or is his air system going up to the stock snouts?
This filter setup,up front may be better and eliminate the filters inside the straights.

dprantl

That is a stock shroud. John adds all the stuff forward of the shroud (above and in front of the radiator).

Dan
'91 928GT S/C 475hp/460lb.ft

docmirror

The equation you're looking for is Boyle's law. Well, a reasonable proximity anyway. In general form it is PV = NRT. Where P = pressure, V = volume, N = number of molecules, R = molecular constant of air, T = temp.

So, the increase in pressure is a direct inverse to the increase in temp, and vice-versa. Classifying it as rounding errors seems a bit disingenuous.

I wouldn't mind seeing your calorimetry tests.

inactiveuser1

Dan,
thanks for the answer on the stock shroud and only mods above and in front.

mark kibort

You think Im looking for that?

I'll let you go through the numbers, but what I can say , is that the temperature introduced is a rounding error in the gains, as they themselves are rounding errors as well. (or close anyway because we are talking about 3-6% in total max anyway).

If you double the air temp in a car tire (in F degrees) does the pressure go up double as well? The volume doesn't change that much, no more molecules are introduced, however, there can be some changing of state of air with moisture in it.

docmirror

Yes, it does. Provided the temp of every molecule in the tire is actually double, and the tire doesn't grow at all. Both are very, very rare occurrences, but that's the way the formula works.

The other issue isn't the aggregate addition of heating effect from the motor, but the heating effect of the adiabatic rise due simple to compression. This is what intercoolers are designed to resolve, and why they are so useful.

inactiveuser1

Stephen,
This might be what you are looking for on Knight's electric.
http://www.turbomagazine.com/tech/04...ger/index.html

droy3

...is that Boyle's law or the ideal gas law? Not nitpicking...just curious.

mark kibort

You missed it. . temp double would have to be the temp based from an absolute zero, not F. 70 to 140 degrees F, doesnt equal doubling the tempurature for Boyle's Law.

So, back to the point. Yes, the motor heating was discussed and its not adding substantial heat to the intake charge based on the volume of air passing over it over time. the compression is slight, the volume doesnt change, so you have more mass flow, albeit at a very slightly higher tempurature.

docmirror

I use them interchangeably, but it's more accurately the ideal gas law. Old school, I'm an old guy.....

inactiveuser1

Built another Y pipe which is lower to the MAF.With the welded collar the air travel from the dual air tubes is a shorter distance coming into the single pipe over the MAF.Difference between the 2 pipes in picture below,lower picture is the short built pipe.Might have a contoller built for my next project of the air intake fans will take months yet but when done would hope the whole air system will be good for 20+ HP

inactiveuser1

Took the car to the track and it was middle of the day which usually isn't as good as when running a car late night closer to 10pm.It was just test and tune day as the regular season hasn't started yet but was able to do some runs for times.
On the left side is from 8/2008 which was the late night runs with stock air intake.MPH was higher with new cold air intake and ET was close to the same
My estimate would be at late night it may drop to high 9.30's as the MPH was around 1.3mph to 2mph higher trap speeds with the cold air intake.
Right side is from 4/2010
Anyone else with stock 928s4 can compare the mph in the 1/8mile as it went to
alittle over 79mph before it always in the 77.mph which the car has never run 79+mph before in the 1/8 mile.Will be interesting to see what the ET will be on a late night run looking forward when races go to nights instead of middle of the day races.
Leaving off the line when the 2nd yellow would light gave some red lights.
Leaving off the line when the 2nd yellow just went off gave .5651 light(reaction time) .5000 is a perfect light.

docmirror

Uh, no I didn't. No where did I reference F or C. I'm well aware of the Kelvin scale, which is why I reference T = Temp, not F, not C, but Temp.

mark kibort

Good, so its a little easier to understand that the mods can give a 3-6% hp gain for a 3-6% increase in net pressure gain in the intake, and heating of the air is a rounding error. In fact, the gains themselves are near rounding errors.

mk

inactiveuser1

Doing some changes on the last system cut back Y pipe to 7 1/8" long.Drew up another collar that is now offset at the top but also angled so when it comes out will be on centerline down inside.This will pull the pipe around 5/16" to 3/8" more away from the firewall to allow for 4" elbows and 4" pipes along the back firewall.Still have to get it welded up and build out from there again.Might be a good setup if anyone who is running a supercharger using the dual air intakes.Not sure what you guys are running along the back firewall for the superchargers that are running the dual air systems if its 3 1/2" or 4" tubing.It may fit in or it may need alittle more angle have to try it out yet to fit.Cutting the Y pipe down further also opened it up more as the Y pipe get wider inside the more the pipe is trimmed back.There is about .100 of area across that is more open now for air flow.Before the Y pipe opening was around 3.30" across and the MAF is around inlet is around 3.40" being the pipe is trimmed back now across it is opened up to the 3.40"
Might work better for supercharger cars that are using the same dual intake system that want to go to 4" elbows into 4" along the back right before the Y pipe and MAF.
Some options are for NA cars:
1)To wait for the new ERAMs that may be 4inch and run them in the back right before the MAF.
2)Make your own fan system into it with 4" to 5" fans would be around 4000 to 7000 watts with the 22 to 24 volt RC system.
3)Put the 4" internal filters out back along the firewall and run 2 EDF 5" fans into the air canisters that are the same on Rogers system which uses the 5" canisters along the sides of the car.Not sure which would be better 5" fans into the canisters where the filters used to be and 4" air filters in the tubing against the firewall or leave the 5" canisters with the filters there and run the 4" fans inside the tubing out back along the firewall that is closer right before the MAF.May or may not get into the fans but for now air flow will be better with 4" elbows and 4" pipes out back along the firewall and the 3 1/2" Y pipe internal area across is increased going to the MAF.The further the Y pipe can be cut down the area across opens more which is the advantage of using the welded collar.Putting the angle into it the collar now allows more room to fit the tubing size to 4" thruout the system.
Top picture is the increased angle which will allow 4inch tubing out back againt the firewall.The pipe goes thru the bore offset but is on center of the area as it enters the MAF.
Bottom picture is the Y pipe cut to only 7 1/8" wide.