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post #1 of 11 (permalink) Old 10-03-2018, 04:20 PM Thread Starter
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Unhappy Boosted LT1 Runs Hot

Hey Guys,
I have a 95 Camaro with a LT1 base 383 built for boost. This is my first boosted engine and I need some advice. Running a Vortech at 10 lbs boost. As the title implies I am having cooling trouble.

I replaced the radiator with an aluminum 3 core, am running a 160 degree stat (replaced twice), electric WP and yes the system is bled but the car constantly wants to run at 220+ when the outside temp hits 80 or more degrees. I know that temp isn't dangerous but I would be way more comfortable at 180/190.

Now to my real question. I have no intercooler. Could this be the major cause of my problem? Do I need one? Chime in you guys with knowledge and let me know what you think,
Thanks

P.S. forgot to mention that 220 deg is with both fans running constantly and it runs hotter highway then city. Yes I have an air dam.

Last edited by cocobolo95; 10-04-2018 at 07:30 AM.
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post #2 of 11 (permalink) Old 10-04-2018, 07:48 AM
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Yes you need the intercooler. The boosted air charge, because of the compression gets quite hot. This heat is added to the heat of combustion. The cooling system has to deal with the extra heat.

So add the intercooler and give your engine a break.

Does your engine run 220+ all the time, while at idle, or at highway speed? If always, the intercooler will help. But you still might need more cooling capability. As an aside, 220 degrees is considered normal operating temp on these engines. The primary cooling fan doesn't come on from factory until 226 degrees. The secondary cooling fan comes on at 236 degrees.

Back to running hot. If idling runs temp up, better cooling fans would help. And make sure fans are pulling air into radiator. Not pushing air out from engine compartment. Dc motors will run in either direction, depending on which lead gets power & which gets ground. Make sure fans are pulling air into rad from front of car.

If hitting 220 at highway speed, since you have airdam, more cooling capacity is needed. Or fans are pushing air out of engine compartment, rather than pulling air in. If fans are running backwards, at idle and slow speed driving, fans are able to move air through rad. But as you go faster, the air moving through rad is being fought by the fans trying to push the air back out of engine compartment.

My 90 3.1 v-6 daily driver, has the cooling fan running backwards. It's just a stock 140 hp car. But on those rare ocassions that I'm on the highway, I have to turn rad fan off. Because coolant temp gets hotter with fan working against the natural flow of the air stream.
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post #3 of 11 (permalink) Old 10-04-2018, 07:52 AM
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One last thing, since lt1 uses reverse cooling, are all hoses & pipes hooked up correctly? And did you put the steam pipe system back on at the back of the cylinder heads?

These are essential to the cooling of the engine. Even on stock lt1 engines. So on a boosted engine, they are even more essential.
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post #4 of 11 (permalink) Old 10-04-2018, 04:58 PM Thread Starter
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The car actually runs hotter on the highway then in city. I failed to mention in my original post that to keep the car at this temp I have to run both fans continually (they are toggle switched) and are stock fans. Fan rotation is correct. Yes, all hoses (including steam hose) are on and correct. This is my first 4th gen Camaro and first LT1 so thanks to shbox I have found much info. Someone else asked about the shroud in front of the radiator? I don't have one but was told there should be shrouding in front of the radiator to direct airflow. Learned this yesterday and have yet to figure out what I'm missing? A/C is deleted so there is no condenser in front of radiator, just a trans cooler and it is smaller then the condenser was so should be less restrictive to airflow.
Car runs strong, doesn't boil over or lose coolant. I bought this car at the start of summer with blown head gaskets (took a chance and ended up with a good deal) and I do all my own wrenching so I have already become fairly familiar with the LT1. I was told by previous owner that he overheated it and took out the head gaskets and the radiator in it was a stock unit with a broken plastic tank and I assumed the radiator failed. Both heads were good, no warp, just replaced the gaskets (.098 thick Cometic). Also my WB O2's tell me I'm running an A/F ratio of 14.6:1 to 15:1. Varies in that range continually. Is this just a touch lean and could it be contributing to extra heat?

383 LT1 8.66:1 CR forged internals
Long tube headers w/3.5" exhaust
LS1 24x conversion
Modified Victor Jr intake
LS1 95MM throttle body
Vortech S/C 10 lbs boost
TH400
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post #5 of 11 (permalink) Old 10-04-2018, 05:55 PM
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lean mixture will cause more heat from combustion. I'm not a boost expert by any means, but from what I understand, boosted engines require a richer mixture to help prevent melting pistons, among other things.


I believe most people with superchargers or turbo chargers run much larger than stock fuel injectors. And must tune pcm to get correct air/fuel ratio for max power & max engine life.
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post #6 of 11 (permalink) Old 10-04-2018, 06:33 PM Thread Starter
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The A/F ratio I mentioned is at cruising speeds in closed loop operation. When boost is introduced at WOT the pcm goes to VE tables for A/F ratio and O2's are ignored. Can't hold it WFO long enough to see if the richer mixture would bring the temp down. LOL! My injectors are 48#. This engine is capable of 650+ HP on 93 octane pump gas as it's set up now and 800 HP if I should choose to go to a 52# injector and tune for E85. I'm an old gearhead. This is my first foray into the world of computer run hot rods. My last car was a 67 Chevelle with a 327 so I'm learning a lot.

Last edited by Pointless; 10-04-2018 at 06:43 PM. Reason: additional
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post #7 of 11 (permalink) Old 10-07-2018, 09:18 AM
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Not to hijack your thread here, but I have a similar issue. I have an LT1 in a third gen car, that now has a 78mm turbo, and is intercooled. Same deal as you. It wants to run 220 all the time putting around, up to 240 if I run her harder. Previously, same cam, heads, etc., it ran 180 all over, with only 1 fan hooked up (fourth gen fans / radiator swapped in), and the fan was rarely needed (stock radiator still too).

Now with the turbo and intercooler, sitting in the garage it'll climb up. I'm really surprised, I put all the plastic deflectors, air dam, etc., back on there too, and the temp slowly rises up.

Did you figure yours out yet?

J. Moen
91 Camaro Road Race American Iron car - The Menace
91 Camaro RS - '93 LT1/T56 swap project, 10.5:1, 224/224 @.050, 60lb Deka, home ported heads, 78mm Vs Racing, intercooled, 2 bar MAP tune on $DA3
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post #8 of 11 (permalink) Old 10-07-2018, 03:18 PM
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If all else fails to bring coolant down, you have to think about what boost does. It's forcing way more mixture into the cylinders and producing at least 50% more heat than stock or mildly modded engine.

You might have to add extra cooling capacity beyond what you have to bring coolant temps down. But I doubt you'll be running 180 degrees with boost.

I suggest trying a forum that specializes in boosted engines. Even though members on these forums are probably not running the same engines in the same cars as you, the principals are still the same.

They should have members that have worked out the problems associated with boosted engines. I have some theory on the subject, but very little actual experience with the problems associated with superchargers & turbo chargers.

Even an inter cooler added to system just cools down the charge going into engine. It does nothing to help the hellish temps in the combustion chamber. Which get transferred to cooling system.

Which brings me to my final subject. Car companies & race teams have teams of engineers that spend months or even years working out the problems of boosting an engine.

Then comes along the driver of a car who wants more power. He will buy a kit to go on his car. But the kit is only the beginning. The engineers who designed the parts in the kit, only went far enough to get a running car when you install. They left many of the problems to the kit buyer & installer to work out.

So lets face it. Very few of us are engineers with the knowledge to work out mechanical problems.

Last edited by cocobolo95; 10-07-2018 at 03:29 PM.
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post #9 of 11 (permalink) Old 10-07-2018, 04:32 PM
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Just took mine out and beat on it a good bit. It's fairly warm here yet, about 88 or so.

Changed a couple things
1) where the intercooler sits was actually forward of the stock plastic dam. This actually makes the intercooler a sort of flow restrictor itself. So I attached some thick shipping foam to the front of the air dam, such that the front of the dam is now at flush with the front of the intercooler.
2) Couple places where the radiator met the support, there was some gaps. I sealed those off with some formed aluminum sheet pieces that I fabbed up real quick. Wanna force the air through the rad, no free trips around the rad. support.


Seemed to help some. Stayed under 220 most all the time, except for those extended blasts under boost. Dang that's fun. Even then, it seemed to come back down under 220 within a few minutes. Around town it didn't seem to heat as much either.

I found out 1 of the 2 fans is dead. So I need a new motor there, and then both fans will work, which should help even more. I think I'll be OK. I guess the intercooler acts like a restriction in front of the radiator. Reduced air flow means less cooling. Thicker radiator might also help some. Also thinking about hood vents too now. Hard to cut such a pretty piece of fiberglass though. Ouch.

J. Moen
91 Camaro Road Race American Iron car - The Menace
91 Camaro RS - '93 LT1/T56 swap project, 10.5:1, 224/224 @.050, 60lb Deka, home ported heads, 78mm Vs Racing, intercooled, 2 bar MAP tune on $DA3
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post #10 of 11 (permalink) Old 10-07-2018, 08:58 PM Thread Starter
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Talking

Found out I'm missing some plastic that deflects air through the radiator. I knew about the air dam and it is there but when I got this car the two plastic pieces under the hood were not there and I didn't realize they were missing. Already found them on ebay and just waiting for delivery. We will see.
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post #11 of 11 (permalink) Old 10-12-2018, 07:40 AM
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Quote:
Originally Posted by Pointless View Post
The A/F ratio I mentioned is at cruising speeds in closed loop operation. When boost is introduced at WOT the pcm goes to VE tables for A/F ratio and O2's are ignored. Can't hold it WFO long enough to see if the richer mixture would bring the temp down. LOL! My injectors are 48#. This engine is capable of 650+ HP on 93 octane pump gas as it's set up now and 800 HP if I should choose to go to a 52# injector and tune for E85. I'm an old gearhead. This is my first foray into the world of computer run hot rods. My last car was a 67 Chevelle with a 327 so I'm learning a lot.
You have way to small injectors if you plan on making 650hp. Your current sticks get you maybe 550hp crank if you run LTX rail pressure.

52# stick and 800hp would never happen.

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Originally Posted by sweetbmxrider View Post
I have a heavily modified lt1.


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