Problem or just heat soak?

[97ChameleonTA]

Sorry for this long winded post but any assistance is appreciated.

Okay, I took my Z to the track last week parked for an hour to cool down and ran a best of 12.002@117.43. That was actually on my 4th run of the night and hot lapping. All of those first four runs were in the 117's in the 12.0-12.1 range. DA was +309. After that run, I parked her to let her cool down for about an hour hoping to bust into the 11's. From that point forward my MPH dropped to the 115-116 range and was running 12.2-12.3's. All of my 60' times were in the 1.8's.

Went again last night, a slightly warmer and more humid, DA was +508. Did the exact same thing, got to the track and let her cool down for an hour. The same thing happened again, but with a slight difference. I was running 12.0's on my first runs with 1.8 60's but my best MPH on those early runs was 115.5. And it went downhill from there. By the time I called it quits I was in the 113-114's.

What gives? It seems to be pulling timing for some reason. Is it the stock HX/reservoir? I've never had a car go slower on me as the air cooled down.

[jessrayo]

What happened to your 60 foot times on the passes after you let it rest. Some people are finding the tires cool down too much and tire temp makes more difference than the engine temp.

[gen=5]

Most likely your going to need to swap out the hex and the res,try the D3e set up,its the largest,and it a 3x bypass...that stock set up is a freaking joke IMOP ..On the plus side your be able to know that your going to have the added protection with it,that was the main reason i did it.

[97ChameleonTA]

Originally Posted by jessrayo

What happened to your 60 foot times on the passes after you let it rest. Some people are finding the tires cool down too much and tire temp makes more difference than the engine temp.

They were all consistently in the 1.84 to 1.87 range. I've been drag racing forever and am pretty consistent and I don't think I could do much better with the stock GY's unless they super-prepped the track.

It's falling off in the MPH that is troubling me the most. Especially going from mid 117's to mid 115's with only a +200ft DA difference. That difference should be negligible.

[97ChameleonTA]

Originally Posted by gen=5

Most likely your going to need to swap out the hex and the res,try the D3e set up,its the largest,and it a 3x bypass...that stock set up is a freaking joke IMOP ..On the plus side your be able to know that your going to have the added protection with it,that was the main reason i did it.

I'd agree with you except for one point, I got my best run on a 4th hot lap. And it doesn't explain the 2MPH difference I lost in a week unless maybe the pump is going south on me.

[97ChameleonTA]

BTW, the D3 HX and res are on my to do list though.

[hognutz]

I would datalog the runs. that will tell you the story. I assume you were running all nannies off.

if the IAT2's get too high it will pull timing. if it pulls timing though you MPH should be down on the big end.

one would assume it is a heat issue. the cooling system of the car I think is designed more for road racign which you have much more airflow on the HX on aroad coarse than drag racing. drag racing you have 100% load then a shutdown and no airflow.

For drag racing I think thing the superchiller is the best solution I have seen. you allways have cool air if you go that way.

[white ZL1]

Originally Posted by gen=5

Most likely your going to need to swap out the hex and the res,try the D3e set up,its the largest,and it a 3x bypass...that stock set up is a freaking joke IMOP ..On the plus side your be able to know that your going to have the added protection with it,that was the main reason i did it.

Really? Explain why?
What IAT2's were you seeing with the stock parts and what are you seeing after?
And if the stock setup is a joke, why have both Ted Jannetty and Andy Mages said on this forum that the stock setup is more than adequate with certain combinations depending on your intended usage and goals?
And the fastest bolt-on only ZL1 on this forum doesn't list a h/e, pump, or reservoir upgrade on his mod list.

[97ChameleonTA]

I went out and ran the car in the driveway for a little while and felt the intercooler hoses. I can squeeze them almost flat easily and when I do I feel very little flow. Is that normal?

[97ChameleonTA]

Sorry to be a pain, but I would really like some input on this. What does your intercooler pump hose pressure feel like if you squeeze the hose at idle? This is driving me nuts (or, at least a little more nuts than usual)!

[white ZL1]

Fairly easily? Yeah.
Not sure what kind of flow you're expecting to feel, but you can tell there is fluid in both hoses when you squeeze them.

[casper73]

Just a thought if you have a temp gun, take the temp at the top and bottom of the heat ex. There should be a drop. You could also use it to check the tire temp at the track before each run. Good luck

[jessrayo]

I have suspected that driving the car with the engine at low rpm is probably the best way to keep heat down. As your engine rpm accelerates the supercharger does about 3 times the speed and really gets hot over 6000 rpm. I can't see how letting the car sit could contribute to increased IAT's and compared to road racing the car for 30 minutes, the 12 second drag pass is absolutely nothing. The IATs rise when the rpm's are over about 5.5K then they come right back down as soon as you shift or cross the line and get out of it.

It sounds to me like you may have air in the lines though... I can see that being a problem. It can be a pain to fill because just adding water does not work. It has been so long since I had a stock filler.... If I remember right you can remove that lid and fill with it running. With the engine running you should be able to remove the filler cap and see it flowing. You may have to fill, turn off the car and let it sit a few minutes, fill, start and remove cap, fill again.....stop. If you can't see it moving when the engine is running you have air in the system and it really does not flush out well. From what you are describing I suspect this may be the case. When you don't have enough water in the system the IAT's come up real quick.

[97ChameleonTA]

Now that you mention it, it does feel like low flow with bubbles when I squeeze the tubes. Is there a bleeding process online somewhere so I can rule that out?