monitoring intake temps

[Bret Brinkmann]

I was planning on getting the duel IAT gauge from Auto-Meter. The main reason I like the idea of monitoring IAT is for detonation prevention. It's obviously important enough for all the manufacturers to take into account so it will be important enough for me to monitor at the least. If I know what temp the air is I can help prevent it before it starts as oppossed to reducing it once it has already started. (In the case of monitoring EGTs and O2s. I would monitor these also though.) has any one had any experience or heard any thing about the Auto-Meter IAT gauge?

With the readings you get from the IAT gauge you can actually see what difference in temperature those new ICs make or don't make. If you are recording this information as well as boost during a dyno run then you could get a general idea of the power loss/gain due to intake temps and boost. Like maybe a 1 psi increase in boost produces 10 HP and 10 F decrease in IAT also creates 10 HP. (Don't think those are accurate numbers just throwing some thing out there for conversation sake.) While monitoring your IAT you can see how much the air temp increases for each 1 psi increase in boost. Evenchually you will reach a point of deminished returns and start heating it more than you increase pressure. You could also more easily find the higest efficiency range for your hybrid turbos as definded by lower IAT readings.

I know I have said it before but I'll say it again anyway, I don't like piggy backs for this very reason, they take away a varible from the ECU and make it a constant. Thus the car looses some of it's fine tuneing resulting in less gas mileage, idle stability, drivability, and (most importantly to most of us) ultimate power potential.

[twospoons]

Originally Posted by Bret Brinkmann

With the readings you get from the IAT gauge you can actually see what difference in temperature those new ICs make or don't make. If you are recording this information as well as boost during a dyno run then you could get a general idea of the power loss/gain due to intake temps and boost. Like maybe a 1 psi increase in boost produces 10 HP and 10 F decrease in IAT also creates 10 HP. (Don't think those are accurate numbers just throwing some thing out there for conversation sake.) While monitoring your IAT you can see how much the air temp increases for each 1 psi increase in boost. Evenchually you will reach a point of deminished returns and start heating it more than you increase pressure. You could also more easily find the higest efficiency range for your hybrid turbos as definded by lower IAT readings.

EXACTLY!!! i want to know where the point diminishing returns is at in relation to boost pressure.

[95red3000gt]

I think this is a really good idea you have goin. I like the idea of being able to prevent knock before it happens rather than using EGT's and 02's to monitor while happening then trying to correct. I think that would greatly help us 10:1 tt conversion guys seing how we make a pretty good amount of heat with the 10:1 .

[2Mitsus]

Originally Posted by Multiades

I know I've seen devices like this before, but where can I purchase an inexpensive fast-reacting air temperature gage, or possibly a differential temperature gage (obviously with two inputs).

It would be very useful to be able to quote peak air temp in the plenum.

-Chris

You mean something like this?

Product Description

Made of real aircraft materials. Display color is orange Dimensions : 2.50 x 1.10 x 1.00 Temperature measured in Fahrenheit SP Temp meter has three different modes: Temperature inlet Temperature outlet Difference in temp

Details

Price: $249.99
___________________
Dynamic Racing sells them

[Jeff Lucius]

The above kit looks slick. I don't think it was available (or I didn't know about it) when I bought the Autometer kit shown below. The link below has SP kits available for $225.

http://www.sp-power.com/catalog/prod...oducts_id=1218

I have the Autometer 3373 dual intake temp gauge. The two probes are installed before and after the left "Alamo" IC in my custom 2" steel pipes. Best price I found was at egauges.com - $257. Other options are to use real datalogging setups with k-type probes.











I doubt there is much temp difference from just after turbo to just before IC and from just after IC to plenum. The other interesting place to measure temps would be before the turbo (or at the air filter).

Using temps to judge performance is just not as simple as a person would like it. The main complication of high intake temps is the increased tendency for knock. The second consequence is slightly reduced density for a given boost level. A person could use my web pages below to investigate different combinations of boost and temps and IC efficiency to find out the changes in air density. But generally, more boost means more air mass. Rarely does the temp increase due to higher boost *after an IC* cancel out the benefits of more air flow with more boost.

http://www.stealth316.com/2-turbotemp.htm
http://www.stealth316.com/2-air-fuel-flow.htm

[JD-01]

That kit has been around for a while... look closely at the center console:
http://www.clan-davidson.com/jd/vr4/...3-0372_IMG.JPG

-JD

[Jeremy R]

So is the IAT a more reliable tuning device then say the EGT?

[Bret Brinkmann]

stealthvader - EGT is probably a better choice to start out with. It gives a better indication of the combustion chamber temps. (Don't want to melt any pistons.) Once you get more comfortable with tuneing (especially for stand alone tuners) IAT would help out a lot in fine tuneing the car.

Jeff Lucius - Does the Auto-Meter appear to give a live reading?

[Jeff Lucius]

I don't see how air temps are much useful for "tuning". They provide curiousity info and help evaluate components and component changes. But there are no tuning changes (adjustment of fuel delivery, ignition timing, or valve timing) that need to be done based on air temps in the plenum, at least none that the ECU or piggyback are not already doing. If temps are high then something needs to be done to lower them - WI, AI, PI, better ICs, better routing of air through ICs, turbos with better efficiency, etc.

One very nice feature of the Autometer setup is the peak-hold-recall function. Just like with EGTs and boost, it is often very hard to carefully observe the meter to observe and record the max values when operating the car at max performance. Datalogged values would be even better (Defi setup for example). I recall both peaks and use that to calculate IC efficiency, which is about 75% for my "Alamo" ICs according to some preliminary tests.

Temp probe response is usually closely related to the thermocouple size. The Autometer probes have a very small size. They respond quite rapidly as far as I can tell. But I do not know what their time constant is. The "time constant" or "response time" is the time required to reach 63.2% of an instantaneous temperature change. Practically what this means is that it takes about 5 time constants for a probe to accurately report 100% of the current temperature. Typically probes with bare wires with diameters of 0.01" have response times of about 1/5 second, with 0.02" diameter a response time of about 1 second. The wire on the Autometer probe is ~0.025". So we could expect the response time to be about 1 second. This is I believe fairly typical for probes of this type.

[twospoons]

Originally Posted by twospoons

what temps are you seeing at the plenum?