p99ta

Components:
408 ls1 low compression iron block with forged components
mild cam
turbonetics t-76
160 thermostat
mechanical water pump
big aluminum radiator
2 medium fans pushing
1 big fan pulling
kept air conditioning (mounted between intercooler and radiator)

Temperatures are 210+ on highway

Stop and go temps are at the tick between 210deg and 260deg and then begins soaring.

Any ideas on what to do? This can't be normal right? All because of keeping a/c in the car?

Thanks for any input!

Here are some pix:

OUTLAWZ RACING

iTrader: (9)

t76 408?????? Take the big puller off and see what happens, also be sure u have no air in the cooling system.

czwalga00gt

iTrader: (3)

This... i bet you have air in the system, especially if you're not using an expansion tank.

p99ta

Thanks for the replies! Ima ask the man if he's checked out that stuff...

So with my setup with air conditioning it shouldn't be hitting over 210-220 in stop and go traffic right? That IS abnormal?

p99ta

There is definitely no vapor lock / air in cooling system... also thermostat has been changed...

New heat shield has been put in... see pic below...

Engine still overheating during stop n go traffic...

any ideas? Does anyone else have a similar setup? ls1 346 or 408, t-76, big radiator AND kept a/c? I'm wondering if the condenser and radiator are both just two thick for any airflow in there? Or is it most likely the mechanical water pump isn't flowing enuff?

SpecV44

iTrader: (7)

How many CFM are your 2 pushers pushing? Can you feel the air coming out the back (engine side) of the radiator when they are on? I bet you need more airflow. Where are your pushers mounted, stock location? What are your fan on temps set to?

98Z28CobraKiller

iTrader: (17)

Is the plastic air dam still in place under the radiator. It's way important.

p99ta

Not sure the exact CFM for the 2 pushers but was told puller is 1000 cfm. The puller is definitely bigger since the condenser is smaller than the radiator.

The setup is like the following from engine to front of car (pix following):


Engine
T-76
pull(fan)
=========== Radiator
-------------- A/C Condenser
push1 push2
fan fan
=========== Intercooler

(Front of car)



New PIX:

p99ta

Plastic air dam is definitely in place. Doesn't that only help/affect speeds of 30+mph though? This only occurs during stop and go traffic.

SpecV44

iTrader: (7)

then you need a shroud on your fan(s) to ensure they are directing that 1000cfm through the radiator instead of around it (path of least resistance). you can try it with cardboard and duct tape first. i would do the front first (the 2 fans), also ensure you have no gaps/openings around the radiator.

what are your fan temps set to turn on/off?

p99ta

Not sure what temp the fans are set to come on but they come on early and my friend found a setting that was so weird before... from factory it's set to turn the fans off after 30mph so he set it to shut them off at 100mph.

The shrouding thing might be the ticket... I dunno... there's definitely not enuff air flow. This proven from yesterday... the real feel temp was 100+degrees yesterday and on highway, the engine stayed around 210-215. As soon as I get caught up in traffic, it starts creeping up at first and then soars....

nahasapeemapetalon

iTrader: (9)

I am having similiar issues.

2000 TransAm, 408, afco dual pass radiator, with two 1000cfm pushers (fail), and one 1200-1400cfm puller with no shroud. It does ok but with higher temps it cant hold the temp down. I plan on coating my hot pipes and maybe even wrapping them too. I have a single gt-88 with wrapped pipes now, underhood temps get very hot. I plan to cut rectangular holes in the back of the hood to let air flow through as well.

The main upgrade I am planning is a nice 2000cfm or so puller with a shroud. I only have room for a 12" fan.

I assume your pushers are crappy like mine and dont do near enough.
Good luck.

p99ta

Yup... I don't know if you can see but my hot side is already wrapped and my friend/mechanic even made a heat shield for the turbo with insulation for the hot side of it... still no luck...

Definitely not enough air going through. I think my two pushers are 1000cfm but I guess not good enough to go through the condenser and radiator.

98Z28CobraKiller

iTrader: (17)

You should not have pullers and pushers on the same radiator. The reason that the factory shuts the fans off over 30 is because the fan becomes a restriction for air flow over that speed (thanks to the airdam).

If you can fit one puller between the turbo and the radiator, you should be able to fit 2 pullers and eliminate the pushers all together. If this isn't possible, remove the puller and try just pushers. Do not shroud that single fan. I am fairly sure that will make your problem worse.

NicD

iTrader: (7)

You have no shroud with the radiator pushed forward and a big turbo sitting right behind it nearly touching... yeah it's going to get hot. You just have too much heat in all the wrong places.

TT350

If you still have the instructions for the fans read them carefully.
Some fans are advertised as “reversible” but there’s more to do than
switching the wires.

Some fans require you to remove the blade and turn it over as well as reversing the
wires.

This is most common with “S” blade fans.

Also check that you pusher’s are pushing and the puller’s are pulling.
I have seen this mistake is made more than you might think.

The best thing to do is pull the fans off the car and bench test them
to see witch direction they move the most air.

I’ll leave you with one other thing to check,
If it’s running hot in slow traffic and sitting idling
and the fans check out it is recirculating it’s own hot air.

black98ws6ta

iTrader: (77)

160* thermostat?

It is best to have a pair of fans as pullers and them being shrouded across the whole radiator.

SpecV44

iTrader: (7)

Yep, he is right. It is the same reason clutch fans disengage from the motor.

Double check that your fans are flush against the radiator, no gaps. Much easier to push air around the radiator, than through it.

bboyferal

iTrader: (9)

This...

And I should mention that I run two pushers and one puller, too, and I STILL had overheating while at a stop/slow traffic, especially with the AC on.

The air needs a way to escape at a stop, and what worked for me was to cut the cowl by the windshield enough where air can escape. After doing that, I could feel really damn hot air coming hard out through the cowl at a stop and my overheating problems went away. Right now, your fans are just blowing hot air into hot air maybe.

Plus, it's really cool while at a stop to look out through my windshield and see everything wavy, lol.

Anyhow, this worked for me, and btw my turbo placement is identical to yours.

TT350

I don't know what brand of fans you guys use for these applications but
Spal makes the best in the business.

There site has all the info you'll ever need to choose the right fan.

Most fans companies rate the CFM's at free flow.

Put it on the radiator and the CFM falls way off because
the motor don't have the stones to to move the air with the
restriction of the radiator core.

The Spal fans have there CFM ratings with vs static pressure.