obzidian

(Sorry about the long post btw. Cliff notes: IAT's 167-190* @ WOT/Cruise/Idle = BAD! Need to lower then = HELP!!! )

I'm helping out a friend sort some of the "issues" with his car. The set is:

2001 C5 LS1 Auto
Stock Longblock.
Maggie Kit with intercooler (MP112)
Intake, Short Headers, No Cats and a Catback.
Stock Thermostat, new plugs and wires.
DAILY DRIVER.

His biggest complain about the car was that it wasn't "performing as it should" as the car would get beat by reg. bolt-on C5's. The car ran around 110mph in the 1/4. So we finally meet up yesterday and did a few scans to see what was going on.

Nothing didn't really jump out at me as needing any major changes however the IAT's were just through the roof!

Ambient last night was in the low 80's.

The IAT's at idle would hover around 160*. (80* over ambient!)

I thought that perhaps she was heat soaked from the drive so we drove around normally to see just how far down they would go.

The IAT's at cruise were the same if not a few degree's worse. 165-167*.

This is after 10 minutes or so of cruising at highway speeds (50-60mph+).

Soo... I was interested to see just how much timing was being pulled at WOT and check other parameters.

The IAT's at WOT went from 150* to 196* !!!!!!!!!! (We did a few 1-3 gear pull to redline starting at 20-30mph.)

The IAT's at the beginning of the run would drop about 10* however would immediately creep back up and by 3rd gear she was well over 190*. That is over 100* over ambient!!

Timing being pulled (scanned for timing advance and IAT advance) would range from -3* to -9*.


Soo... that's bad! ... and I have tons of questions.

Has anyone else seen IAT's this high before? I know PD blowers just run hot but IAT's this high seem abnormally high. I have seen other PD's run around 20-50 over ambient... never anything close to 100* with a properly running setup.

Simply put... the stock HE is not adequate enough to drop the temps down low enough and keep them down. The only problem is that there isn't much room in these vette's.


So...I'm looking for some advice on what is the BEST way to cool the car down. We talked and I suggested that we start with a new thermostat and perhaps add two small fans to the HE. and a shroud to direct air. (I doubt that they would really do much but it couldn't hurt.)

I see that to really make a dent we are going to either replace the HE or add a water/meth kit or even one of the cooling solutions using the a/c lines.

1. Are there any aftermarket HE's that have some REAL results in cutting down the IAT's?

2. Water/meth? I have searched around and know of a few kits that I have used before in the past that work well. However, I have no experience with a kit on PD blower.

The first thing you always hear is that the water/meth will hurt the coating on the rotors. In the real world, how true are these claims? Are you guys spraying it before the blower or after? My friend even mentioned to me that he didn't want to run the meth for this very same reason however I want to know exactly how true those claims are and what one would REALLY expect by running a boost referenced kit (perhaps 100% meth??) on a daily driver?

Is a mix of 50/50 water/meth fine? Again, how about 100% meth?

Or how about just spraying a small shot of nitrous? Any REAL success with that?

My goal, if possible... is to get the car back down to regular temps... probably somewhere in the 120's-130's.

I DO NOT feel comfortable removing the timing reduction in the IAT advance table at temps as high as this.

Thanks in advance guys!

Pekka_Perkeles

First things first.

Do you have a proper airflow through all intercoolers and radiators?

For example, never get rid of a front spoiler, which creates vacuum in lower engine department and helps airflow going trough all necessary radiators. Also, make sure all radiators are clean.

breecher_7

Sounds like a typical PD blower to me.. I saw IAT's of over 200 degrees on a kenne bell unit a couple years ago.

02402ramair

Is the IC water circulating? Whats the temp of the water? Whats the inlet temp and outlet temp on the heat exchanger.

That is some crazy high Kenne Bell type IAT's

I saw a Kenne Bell with so high temps it would melt the IAT sensor. Maggie's seem to be much better and should not get that high

obzidian

By front spoiler do you mean the front air dam? To the best of my knowledge the car didn't seem to have a lower air dam installed. I'll ask him about it. I just spoke to my buddy and he is taking a look at the reservoir for the blower to see if she is flowing correctly.

I'm starting to wonder if there is in fact a mechanic issue and this is really not that normal of an occurrence. I'll report back soon.

obzidian

My thoughts exactly. I have never seen a magnuson/maggie get this high. Hell... I know of jeep that has a side mounted kenne bell on a truck engine that has great IAT's... but it is also plumbed with a A2W.

About the circulation.. I took a quick peek last night and saw some bubbles forming however not to much in flow/circulation through the tank. Will get back to you on that.

How are you taking those measurements? Laser-surface temp readings?

Pekka_Perkeles

Yes, front air dam.

I know you won't believe it. I didn't believe it either, but my friend actually measured the difference of not having air dam and having it. And the difference was huge.

Try to put air dam or similar back to the original position. It won't cost you much. But it will make a difference. There's your mechanical issue. Or prove I'm wrong. :-)

obzidian

LOL ... hopefully I won't! Yeah... the car does not have an air dam on it.

He gonna see if he hunts one down today.

What is interesting is that this is the second C5 within these last two months that I tune that both have -9* of timing be pulled however the other was a hacked tune that needed to be repair. The spark table was reeeeeally bad!!

02402ramair

laser temp gun to take readings

The air dam does help but only driving down road. It does nothing for temps while sitting still.

I would inspect IC pump, direction of flow and air across heat exchanger

obzidian

ok... no problem.

The IAT at idle I can understand however when moving the car is not cooling, at all... it gets worse. The pump is mounted on the passenger side, I believe. What is the stock flow direction?

_zebra

and just some input on the meth issue:
you can use meth on a maggie, but it has to be 100%. none of that HEET, warsher fluid, 50/50, etc. you can spray right down the air bridge like usual

obzidian

About that.... what would be the worst that would happen if you happened to strip all the teflon off the rotors? There are a few folks still producing power with water/meth and their combo's so it's not like the rotors will just stop compression air and stuffing the engine? Perhaps a slight loss in overall efficiency?

I have read and read TONS of threads where folks mention that and in reality there are no threads where someone stated their blower came apart or "stopped working" because of the meth.

_zebra

from the research i found while looking into meth for my 2300, i found that the biggest issue is that straight meth vaporizes fast enough & flashes at a low enough temperature that it goes through the rotors as a gas while the diluted mix stuff is still a liquid. the harm there is that liquids don't compress & therefore forces a bigger gap between the rotors (and the chemical properties of it are also a little corrosive to the coating). this, in turn, decreases the efficiency of the unit because it's losing a little of its pressurizing capability from the degraded sealing capability... or something to that effect.

LedfootLarry

another thing you can check, does it have a catch can? If not , oil injested can clog the fins on the heat exchanger mounted underneath the blower. I have heard when this gets clogged, it can also help to cause heat soak

obzidian

It seems that most of the companies that sell alky/water/meth kits state that the heat IS enough to also vaporize the water molecules and not cause physical damage to the bearings, for example and/or cause pitting in the rotors. However what is acknowledged is that the coating will be removed with the use of their kit but I know of plenty of GT500's and some cars on here that are running meth and are showing no signs of REAL damage that is felt i.e. less efficient blower.

No matter.... its an exhausted debate.

obzidian

I just mentioned this to him last night. He mentioned that the car was sucking down oil a lot. Nothing new there... LS1's have a taste for oil.

Small Update:

So between yesterday night and last night the following "changes" where made:

1. Fill supercharger reservoir to the top with distilled water. It seemed to be low... actually it was a low about 2-3 quarts I think. Not good.

2. Added some water wetter to both the radiator and supercharger reservoir. I didn't think this would do much but something is something.


As to the results, we were surprised to see that those few tweeks really went a far in trying to get the IAT's under control.

For starters, the IAT's last night would climb in 3rd gear @ WOT anywhere from 149* - 154* .. so they would be around 160* and by the top of 3rd they would around 199*.

Now, last night we did 10+ runs from, again, anywhere from 149* to 152*. On average, the IAT's would only climb 10*-13*. At the most she would gain 20*.

We were surprised just how much better the cooling system was running that we did multiple runs to make sure it was repeatable.

Also, the previous night the timing being pulled at WOT was up to -9* Last night the most I was at WOT was -4.5* to -5*. You can definitely feel the difference especially in 3rd as previously the car would literally just stop in its tracks. Like you literally threw out a anchor!


Sooo... this is still with no air dam... we are trying to find one now. (Anyone have a used one lying around? ) Also, the IAT's would also drop quicker last night compared to the previous night and NEVER did they reach anywhere near the 190*'s.

As of today, we are trying to source out an air dam and perhaps try a few little tricks to get the IAT's low enough where I can feel comfortable enough to adjust the IAT table and not have any reduction in timing. They are still a bit to high for my liking though I can reduce the modified by a little... but that problem is still there.

We tried a few runs last night with some cars that we knew the previous out come and the car is definitely performing better.

Ok... I'll report back with out findings. Thanks for all your help thus far.

jerrad

Have you heard about the "killer chiller"? It's made for the 03/04 cobra guys and uses the cars AC to cool the water in the IC system. They get the water temps to the low 40's and it doesnt hurt the ac temps either. Might be able to retrofit the system or at least get an idea of what needs to be done.

http://www.killerchiller.com/

_zebra

^^hmm... that actually looks like a pretty sweet system.

obzidian

Yeah, I've seen that before. Actually I think that would be a great alternative for those that don't want to run methanol and I believe there was/is a vendor on here that had a kit that was similar in function but for the chevy cars.

But, my friend is on a budget and is not trying to go over it. Personally I'm would like to see what needs to be done to get the IAT's inline within a normal range and then go ahead and add parts/kits to make it work even better. I'm confident now that our initial problem was a mechanic issue and so far we are half way in resolving it.

I asked him to order an air-dam which is almost impossible to find locally and the dealer is just crazy on what they charge for one. Talk about a vette-tax! So, air-dam first and then we'll see what I can do in making the tune play nice. So far she is responding well to a few tweeks here and there however the VE/MAF seems a bit off in a few spots. But, she is now taking away less timing and is feeling better at WOT.