: Fantastic Afternoon with "DTE"



PneuBird
06-03-05, 05:14 AM
I spent most of wednesday afternoon at "DTE" in Ft Wayne, IN. My "V" has the Corsa Exhaust and StealthV FFV on it. Phil and his crew are best in my book. You just don't find a tuner like Phil everyday!! :worship: We made a half a dozen pulls on the dyno to get it just right in the fuel mixture dept. Since the Stage II was originally set up with an open air element, Phil took the time to really tune the "V" with the FFV on it. It was 85 degrees in Ft. Wayne that day and our inlet temps were running at 102 to 104 degrees. That's a little too hot. It's that aluminum tube Rick uses. It's by no means a bad design but it does have a slight heat soak problem. To help get the temp down we installed a 160 degree thermostat. We ended up with 351 RWHP and 341 RWTQ. I'm truly satisfied with the results and look forward to "DTE" getting the lead pipes made so headers can be installed in the near future. For you guys who don't want the B&B headers, hang in there for another two months. You won't be disappointed!!! And yes .... I did beat the cubes several times on the way back to Columbus.... It kept them happy!!! :woohoo: :dance:

cts-v ls6
06-03-05, 09:20 AM
Cool. It's my turn to visit DTE next weekend. I'll post a report.


Jack

Dynotech Engineering
06-05-05, 09:32 AM
Also, the interesting and unsettling issue with that aluminum tube is that the 102*-104* inlet air temperature measured was with the hood completely OPEN with 3 huge dyno cell fans of 1800 CFM each blowing over the engine! The engine speed was kept at 2000 RPM or so to increase airflow through the tube to see if the temp would came down over a few minutes...they never did. We can't imagine just how hot it must really get with the hood completely shut in city traffic during the heat of the Summer... Just some observations Steve and I had.

Regards,
DTE

2004ctsv
06-05-05, 11:01 AM
What was to ambient air temp?

Just the engineer in me, but assume
1. air into filter box at 90F
2. great forced convection heat transfer (U=15) (water to water is +300)
3. no maggie but very slight negative in tube (12 psia?)
given
1. 102F air to TB
2. 4" tube 1 foot long
3. 2000 rpm on 350 cid gives about 700 pounds of dry air (MW=29)

Using
Q=mCp(deltaTm)
Q=UALMTD
Solve for LMTD approximated by delta Tc = 110F

It says that the air blown on the tube in copious quantities was over 200F

If no air external air movement but still 2000 rpm, then drop U to under 5 and external air temp must rise to 400F

I have trouble seeing a 10F intake air temp rise because of a 1 foot aluminum tube. Something else is going on. If ambient was less than 90F, you will pick up more heat but never get to 102F because of the aluminum tube. Air to air heat transfer is extremely poor.

JMVHO
Tony

urbanski
06-05-05, 12:49 PM
lol
engineers rule :D

and DTE...i have documented IATs of 85-100F, which is ambient in May in Texas
:cheers:

StealthV
06-05-05, 01:13 PM
Using a mean 90% volumetric efficiency, a LS6 engine moves 585.7 cubic feet of air per minute at 6500 RPM. Using this volumetric flow rate and the cross-sectional area of the Free-Flow-V aluminum intake tube, the intake air travels through the aluminum tube at 103.3 miles per hour.

Only six inches of the aluminum tube are exposed to the convection (not conduction!) heat transfer of the engine compartment. In those six inches of length, the intake air takes a grand total of 0.0033 seconds to move through the aluminum tube.

Yep, a whole three point three thousands of a second. The laws of convective heat transfer prove that 527.1 cubic feet per minute of air, exposed to the interior walls of the aluminum tube for 0.0033 seconds results in an immeasurable amount of heat transfer to the intake charge. Additionallly, using the cofficients of thermal conductivity to calculate the difference between polyethylene and aluminum, results in only a 28% difference in the overall heat transfer rate.

No matter the intake tube material, it will be the temperature of the surrounding environment. It is basic law of heat transfer. Heat always flows from warmer things to colder things until they are the same temperature. Nothing can stop that. Any mechanical engineer that wasn't asleep through fluid dynamics and heat transfer knows these fundamental principles.

Dynotech Engineering
06-05-05, 01:18 PM
:rolleyes2
84* dyno cell ambient temperature. Believe and theoryorize the issue to death if you want, but the IAT sensor doesn't lie and is accurate with this vehicle. We really could care less if anyone believes the data or not- it's not our product and we have nothing to gain OR lose by posting accurate information here anyway regarding it's function. The data log, our eye's and Steve's eyes (the owner of the car that was in the dyno cell with us at the entire time) all can't be wrong.....

Take it as you wish, the issue still remains.....

BTW urbanski- Phil also earned a Mechanical Engineering degree from Purdue, so we agree with you...professional engineer's have an advantage in applied knowledge. :D

StealthV
06-05-05, 01:20 PM
The throttle body has 3" of air flow length, is made of aluminum and has hot engine coolant flowing through it. :eek:

Dynotech Engineering
06-05-05, 01:41 PM
Which only makes the heat-soak issue worse since the IAT sensor is upstream of the throttle body.

urbanski
06-05-05, 01:41 PM
lol nevermind
:cheers:

trukk
06-06-05, 11:26 AM
Also, the interesting and unsettling issue with that aluminum tube is that the 102*-104* inlet air temperature measured was with the hood completely OPEN with 3 huge dyno cell fans of 1800 CFM each blowing over the engine! The engine speed was kept at 2000 RPM or so to increase airflow through the tube to see if the temp would came down over a few minutes...they never did. We can't imagine just how hot it must really get with the hood completely shut in city traffic during the heat of the Summer... Just some observations Steve and I had.

Regards,
DTE

What temp does the stock tube run, in similar conditions in your experience? Without this info, It's hard to make comparison. I don't think there would be a direct comparison with an open element setup (a la More Performance, Lingenfleter, speed inc.) in a test with the hood open.

Knowledge is power. Thanks in advance for input on this from all.

-Chris

cts-v ls6
06-06-05, 09:43 PM
Just so you guys know, the inlet air temp in a CTS-V runs almost exactly 30 deg F above ambient at highway speeds. [60-80 mph]. I have Stealth's Stainless Steel tube [not aluminum] and a LPE caik. I have seen it as high as 50 deg F above ambient in stop and go traffic. I am measuring the intake air temp right before the elbow that feeds the throttle body and the signal goes to a digital gage. These temps don't vary more than 1-2 deg F under these conditions no matter what the ambient temp is. [What engineer's like to call "steady state"]. When my water methanol injection kicks in, the intake air temp starts to drop immediately and dramatically and depending on how long you're into the juice, can drop to 5-10 deg F above ambient. To Stealth's point, an air molecule is hardly in the tube long enough to pick up much heat, although there is some convection and possibly a little radiation heat transferred. And yes, I'm a graduate mechanical engineer, U of Texas, registered P.E. in 4 states. Empirical data is so much easier!


Jack

Jack

urbanski
06-07-05, 09:54 AM
where is the IAT sensor in the car?

My IATs are always 85-100F as documented by EFILive...with the FFV, in May, in Texas

cts-v ls6
06-07-05, 02:39 PM
My IAT sensor is in Stealth's tube, at the end, right before the elbow that turns into the throttle body. It is as close to the engine intake as I could get it.