High IAT's pulling timing: cause?

[Satyr]

While dynoing my car we found that my car is pulling about 6* of timing. I checked the I/C pump and it is running properly, which has me puzzled. The IAT's start around 100 and get to 155-165 under WOT, and then quickly fall when I get off the gas.

I recently changed my I/C reservoir and radiator reservoir...anyone have an idea of what it could be?

Thanks

 

[Satyr]

just jumped the IC pump and waited for the bubbles to come and refilled and repeated...going to log later on when I get a new oring on the headcooling mod.

bump for any ideas?

 

[03 svtvenom]

Most tuners set the tune to do that. Usually around 150 or so. Contact Rick and I am sure he will answer your question.

 

[metaman]

Those AIT2's sound normal for a upper lower car under wide open throttle. Upper lower pullied eatons ported or not are notorious for pulling timming at the top end of the track. The solution is the killer chiller for daily driving or an ice box for the track.

 

[Satyr]

So there's nothing I can do to lower these temps?

 

[Posi]

It could be as simple as the fan not being directed onto the heat exchanger in front of the car. If it's not on that and the car is basically in dead air they your iat's will be higher. I have personal experience in this with my car. It makes a difference.

With your car cooled down and with no ice those temps are a little high. Were you all letting it cool all the way down? Usually on my car when we dyno it in between runs I'll run a tank or two of ice through the IC and that helps tremendously. Not to help numbers but to make sure it's nice and cool.

 

[cobracide]

You can probably lower the temps with a TS, the heaton is spinning way past it's optimal efficiency and producing heat. What was the dyno reading?

 

[96stanggt]

Are we talking IAT1's or IAT2's? Are you saying the charge temps (IAT2) start at 100* at the beginning of the dyno pull and are at 165* by the end of the pull. Those are extremely high, I've never had mine go over 150*. Maybe you have some air in the cooling system.

 

[MVD]

You can probably lower the temps with a TS, the heaton is spinning way past it's optimal efficiency and producing heat. What was the dyno reading?

Twin screws produce higher IAT2's that Eatons. They are compressors, compressed air is hot air. Eatons just paddle air, and while that is very innefficient it does not produce the heat like twin screws.

To the OP, something is wrong, no way your IAT2's should be that high, especially on a dyno where the load is not nearly as high as going down the track.

 

[Satyr]

The Livelink readout lists the coolant temp at 196 and the downstream ACT at 158.

I was not there when the dyno took place as I had subframe connectors welded on as well and the car was there a few days, so I can't comment on the conditions of the intermediate time.

I have since jumped the I/C reservoir and waited for the bubbles to come through the coolant and turned it off. Then I ran the car with the radiator reservoir off to get any air in the lines out...I topped it off when complete (in the reservoir and the crossover tube).

I am working on figuring out Livelink for myself so I can datalog this stuff and see if it's still occurring. I am just trying to get some ideas as to what the cause of this could be.

 

[jm@ReischePerf]

The IAT's start around 100 and get to 155-165 under WOT

Those temps do seem to be going up quite a bit. Are you certain the IC pump is running at full capacity, sometimes they slow down when they are dying. Could also be lack of airflow through the H/E like Posi said.

 

[jm@ReischePerf]

I have since jumped the I/C reservoir and waited for the bubbles to come through the coolant and turned it off.

If your H/E has a petcock on top you can jack the car up on that side to get it higher, jump the pump and then purge any remaining air out by opening the petcock.

 

[Satyr]

Okay, I will do that in a couple minutes.
Is there a way I can tell when all the air has come out of the system?

 

[03dsgcobranc]

open the intercooler fluid reservoir cap and let it run a while with it circulating, it'll burp all the air out that way.

 

[Satyr]

I did that...just kept blowing bubbles for liek 7-8 minutes. Does that mean that it's done or that it's still burping out of the line? Bubbles would normally signify that there is air coming from below the fluid and rushing up, meaning it's not completely burped.

Or am I wrong and bubbling means it is completely burped?

 

[jm@ReischePerf]

Is there a way I can tell when all the air has come out of the system?

Just open it real slow, you'll hear gas escape and then when just fluid comes out quickly be prepared to close it. Takes 1-3 sec.

 

[03cobra#694]

It could be as simple as the fan not being directed onto the heat exchanger in front of the car. If it's not on that and the car is basically in dead air they your iat's will be higher.

This is what I was thinking.

 

[Posi]

Twin screws produce higher IAT2's that Eatons. They are compressors, compressed air is hot air. Eatons just paddle air, and while that is very innefficient it does not produce the heat like twin screws.

To the OP, something is wrong, no way your IAT2's should be that high, especially on a dyno where the load is not nearly as high as going down the track.

This could be a touchy subject lol.

A twin screw at 19lbs of boost and an Eaton at 19lbs of boost as far as the IAT's go shouldn't even be close. On my car on the dyno at (Whipple) 22lbs with it cooled properly the start of the pulls would be around 80 to 85*'s and then the end is usually around 115-120*'s. An eaton even close to 19 lbs of boost or even 17 lbs is going to be substantially higher than that. We don't call them Heaton's for nothing.

 

[Posi]

Sounds like the OP could have 3 different things.

1. Air in the system

2. Maybe improper fan placement or just not enough air

3. Proper cooldown time in between runs

 

[Satyr]

Sounds like the OP could have 3 different things.

1. Air in the system

2. Maybe improper fan placement or just not enough air

3. Proper cooldown time in between runs

I agree with this.
I think I've burped both systems but am not sure because I don't know what the "symptoms" are of when the I/C and radiator reservoirs are both free of air.

As for the fan placement, I never moved the fan from when the car was stock, so should anything have changed? I did add an aftermarket H/E, but didn't touch the fans. Or do you mean my tune has the fans coming on too late?

The cooldown part would be unbenounced to me, as I was not present during the dynoruns. Thus, it could very well be a factor.

Either way, I got all my datalogging equipment hooked up last night so I can do some runs and log everything. I will post back up later today with my findings (to see if my "burping" made any difference). I also sent Rick an email about getting an updated tune and explained some of my problems to him, though I don't think it's tune related right now.