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Old 08-09-2019, 12:34 PM
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Intake air temps are way too hot.

Hey guys need some help. I took my car to the track today and yes it was hot. However I’m getting super hot intake air temps, to the point of danger. So a little background on the car. It’s a 72 nova sbc 355 with an 88 mm turbo and a front mount air to air intercooler. When I pull to the line my iat is roughly 125-130. By the end of the track at the end of the run which only lasts about 10 seconds the iat go up to 250degrees before it maxes out the graph and can’t be read. The real question is that I don’t an issue with the temps post turbo or even post Intercooler but the temps at the bonnet/carb hat are so hot that even touching the bonnet could burn your hand. Can anyone give me any idea of what’s going on. I can’t tell if I have a restriction whether it’s in the throttle body or if the intercooler is just not efficient

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Old 08-09-2019, 10:01 PM
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How much boost are you making?
.
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Old 08-09-2019, 11:12 PM
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I'm still twisting this around in my pea brain. One of my first thoughts is heat transfer of a inter-cooler goes down quickly as pressure goes up. The temp curves really get aggressive once this gets above 12 psi, which brings us to Techinspector's question about peak pressure.


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Old 08-10-2019, 01:55 AM
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You have turbulence there being the air goes from coming sideways to turning down into the carb. But, the hat would have to be tiny to gain 125+ degrees in 10 seconds. Are the intake runners flaming hot as well?

If you have a wastegate on the turbo, you could back the boost down and see if there's a point where you stop generating so much heat.

Boost is just a pressure reference after all, more pressure=more heat.
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Old 08-10-2019, 04:27 AM
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Wow those are high, the first place to look is make sure you have enough intercooler and no issues with flow. Then make sure you have a properly sized cold air intake with a well flowing air filter. Other things that would help are a larger intake or turbocharger. High Timing or Running Lean would also create a heat issue

I'm on my 13th Boosted vehicle now (mostly Supercharged, but a couple of Turbo's). I have run as much as 25lbs of Boost on a Supercharger and there were a few that had this issue.... I was running so much boost that when I went WOT it would actually suck the rubber Intercooler or Intake elbows closed, (kind of like a radiator hose will sometimes collapse and no longer flow).

Of course Meth Injection would be you easiest fix and also give you some safety and insurance by preventing detonation as well as keeping your iat's in check.
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Old 08-10-2019, 06:43 AM
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Of course, how much boost? Are you making over 800hp?

I'll guess 20+ and over 800. You have one of 3 choices IMO - better intercooler (lots of $), E85 or methanol (E85 is difficult to get at consistent % and methanol is $x2), and lastly - meth/water injection (cheap and easy).

I run meth injection. Look at the graph. I came to a stop, let off the brake and went WOT to 3rd gear (street tires.) You can't see the intake temp (MAT) at zero mph, but it was 127. In about 4 seconds it dropped to 83. The meth turns on at 4psi (125kpa) and full on 8 psi (153kpa). You can see it's quite effective.

p.s. - I run 50/50 boost juice at 15 gal/hr and it actually adds fuel. So with the street tires spinning (less engine load) and lower boost (below 12psi) it fattens the AFR somewhat - into the mid to high 10's. If it's not spinning it sits in the low to mid 11's.

EDIT - that screenshot isn't very legible
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Old 08-10-2019, 08:54 AM
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So it’s an 88mm turbo making 20psi and it makes around 870hp. I do believe I need a more efficient intercooler but the reason I’m not really worried about it specifically is because where the heat really is is at the carb bonnet. On the topic of the cArb bonnet it’s not as smooth flowing as it could be. Sort of a tight turn it’s a spectre carb bonnet. I do have a water meth setup partially installed on the car I guess it’s time to use it. I also plan on switching to e85 because I currently run ms 109 and it’s too expensive not to mention the cooling I could get from e85 would be great.
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Old 08-10-2019, 08:56 AM
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This is the engine bay at the moment. As you can see I wrapped the headers to prevent heat soak. It they still give off pretty good heat. I also insulated and heat shielded the charge pipe section that runs above the header for the same reason
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Old 08-10-2019, 09:31 AM
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Do you run a controller for this setup. I’ve looked them up and thought about it but haven’t run the water meth in like 4 years so I never ended up buying a controller as it would have been a waste of money to buy something to control a system I don’t use lol.

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Of course, how much boost? Are you making over 800hp?

I'll guess 20+ and over 800. You have one of 3 choices IMO - better intercooler (lots of $), E85 or methanol (E85 is difficult to get at consistent % and methanol is $x2), and lastly - meth/water injection (cheap and easy).

I run meth injection. Look at the graph. I came to a stop, let off the brake and went WOT to 3rd gear (street tires.) You can't see the intake temp (MAT) at zero mph, but it was 127. In about 4 seconds it dropped to 83. The meth turns on at 4psi (125kpa) and full on 8 psi (153kpa). You can see it's quite effective.

p.s. - I run 50/50 boost juice at 15 gal/hr and it actually adds fuel. So with the street tires spinning (less engine load) and lower boost (below 12psi) it fattens the AFR somewhat - into the mid to high 10's. If it's not spinning it sits in the low to mid 11's.

EDIT - that screenshot isn't very legible <img src="https://www.hotrodders.com/forum/images/smilies/frown.gif" border="0" alt="" title="sad" class="inlineimg" />
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Old 08-10-2019, 10:56 AM
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Yes I run a controller. A snow performance stage 2 kit. It’s fully self contained in a 2.125 gauge. It is also a boost gauge. It included the 3qt tank, pump and enough for one nozzle. It was less than $400 and we’ve been using it in the street for either 3 or 4 years without any failures.

Regarding heat soak, yup, you’re going to have a bunch with any thing forced induction. It took me a minute or two to get head wrapped around that, but if you think that the turbine is at exhaust temps all of the time (800-1000 degrees). Then you shut off the motor and the heat transfers over the to compressor and compressor housing, then when you refute the car you really need some air flow across the cooler to get that cooled down. At the strip, it just ain’t happening. The same goes for the carb hat.

If you had a normal air cleaner, then when you restart the car it almost immediately pulls in ambient temp air, which immediately cools the intake and carb.

We can cruise at highway speeds on a 90 degree day and have the intake temps stay over 100. Then jab the throttle to full meth injection for 3-4 seconds and it will cool the intake temps into the 70’s and they will never get above 90 again until we come to a stop.


One thing for certain though. Use the meth as a safety unless you have 8 individual injectors for it. All the cylinders are not getting the same affect from it if you have it in front of the throttle plates.


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Old 08-10-2019, 10:58 AM
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Forgot to mention, don’t lose a second if sleep about the flow ‘efficiency’ of your cab hat. Spending money to make it more efficient to pick up hp that is a percentage of the gain if 1/2 a lb of boost is truly a waste of time.

You have all the power you need in terms of air flow - it’s a stiffer wastegate spring or kite duty cycle in your boost controller lol.


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Old 08-10-2019, 04:43 PM
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Quote:
Originally Posted by Pupsvette76 View Post
So it’s an 88mm turbo making 20psi and it makes around 870hp. I do believe I need a more efficient intercooler but the reason I’m not really worried about it specifically is because where the heat really is is at the carb bonnet. On the topic of the cArb bonnet it’s not as smooth flowing as it could be. Sort of a tight turn it’s a spectre carb bonnet. I do have a water meth setup partially installed on the car I guess it’s time to use it. I also plan on switching to e85 because I currently run ms 109 and it’s too expensive not to mention the cooling I could get from e85 would be great.

20 PSI puts you well into the danger zone where heat is very hard to control.


One of the first things is to get pressures on the inlet and outlet side of the cooler to determine just how big the pressure loss across the cooler is. From here you can determine if a larger cooler and or bypass controls would be useful.


I'd like to see a larger pipe on the discharge side as well as a larger bonnet.This would convert some of the velocity to pressure which makes changing directions a lot easier and will release some heat as well.


If the track lets you get away with it a fine water mist over the cooler will greatly increase its efficiency. This doesn't need to be enough to drip, just keep the core wet then evaporate into the passing air flow.



Bogie
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Old 08-10-2019, 05:05 PM
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I don’t have much room for the packaging of larger pipe all through the system. It’s currently 3 inch ic pipe.
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Old 08-12-2019, 09:40 PM
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So I was going through my data log and saw coolant temps got pretty warm by the end of the run as well around 205degrees so that may be a contributing factor since the iat sensor is in the back of the manifold below the throttle body. So I changed from a regular thermostat to a restrictor plate.
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Old 08-13-2019, 08:12 AM
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Quote:
Originally Posted by Pupsvette76 View Post
So I was going through my data log and saw coolant temps got pretty warm by the end of the run as well around 205degrees so that may be a contributing factor since the iat sensor is in the back of the manifold below the throttle body. So I changed from a regular thermostat to a restrictor plate.
205 is not hot IMO, but I'd recommend against the restrictor. If you're making 6-800HP and only climbing to 205 at the end of a 1/4 in a street legal car, then I'd say you've got yourself a well designed cooling system.

If you have a window washer pump and reservoir, a quick way to see what's what is it to install a makeshift nozzle in to air cleaner and let that pump inject pre-compressor. It will not blast tons of washer fluid in, but I'll bet you'll see at 50 degrees lower.
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