Thermostatic valves for the TBI Intake

[Striker1423]

I have contacted a company that makes thermostatic valves to spec, but the limit of the temperatures their valves can work to is 300F. What I'm curious about is how hot the actual intake gets from the heater hose at the exhaust manifold up to the intake? Anyone ever take a measurement?

I figure if I can get new valves produced for a reasonable price we can fix the stock setup for stock tbi engines.

 

[Schurkey]

I have contacted a company that makes thermostatic valves to spec, but the limit of the temperatures their valves can work to is 300F.

Why do you need a thermostatic valve at all? What are you trying to accomplish?

What I'm curious about is how hot the actual intake gets from the heater hose at the exhaust manifold up to the intake?

The heater hose is not "at the exhaust manifold".

The intake manifold at the heater hose area will be at whatever temperature the engine coolant is, typically ~190--230 degrees F.

I figure if I can get new valves produced for a reasonable price we can fix the stock setup for stock tbi engines.

The only GMT400 vehicles with heater valves are the SUVs that have rear heat, so far as I know.

 

[L31MaxExpress]

Why do you need a thermostatic valve at all? What are you trying to accomplish?


The heater hose is not "at the exhaust manifold".

The intake manifold at the heater hose area will be at whatever temperature the engine coolant is, typically ~190--230 degrees F.


The only GMT400 vehicles with heater valves are the SUVs that have rear heat, so far as I know.

I think he is talking about the wax pellet control for the air cleaner thermac system but terminology is key for someone to understand what you are talking about.

 

[95burban]

Yeah, got throw in the trash at 00001 miles.

 

[1997]

as stated thinking he means this inside air cleaner ....

Surging idle on cold start

I think on gear head-ef, and found some guy explaining how to make your own for something like $10. But for me, the time to find the parts and then dealing my lousy electronics build/solder reliability when I’m already frustrated trying to fix something on the truck — it just wasn’t worth the...

www.gmt400.com

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[someotherguy]

Years ago, the sonsofbitches at a local state inspection station failed my grandpa truck '94 Suburban that was 100% stock -OTHER THAN- the flex hose from the passenger manifold up to the thermac unit was missing. Failed the visual, the guy actually broke out a 3 ring binder full of all the points he was supposed to look at, and keyed in on that one.

Anyway other than in really cold climates I don't see much point in replacing these. As others have, I've yanked mine out once they fail (and sometimes before they fail.)

Richard

 

[Schurkey]

It's not "really cold" you need to be concerned about--although having the heated-air intake sure wouldn't hurt.

The genuine concern is 40-ish degrees F., and high humidity/raining. The main problem that the heated-air intake is trying to cure is throttle icing, and that's generally a high-30s, to low-50s problem temperature-wise.

 

[someotherguy]

It's not "really cold" you need to be concerned about--although having the heated-air intake sure wouldn't hurt.

The genuine concern is 40-ish degrees F., and high humidity/raining. The main problem that the heated-air intake is trying to cure is throttle icing, and that's generally a high-30s, to low-50s problem temperature-wise.

Here in Houston / SE TX in general we're almost always extremely high humidity. Of course it isn't as bad when the weather gets cold but still quite humid with plenty of rain, freezing rain, and the occasional snow. Never had any driveability problems with any truck I've pulled the thermac from. I guess it could happen if the conditions were just right but they always seemed to run just fine regardless of weather.

But, to each their own.

Edit - I guess I gotta ask, how many members here with TBI trucks have checked their thermac for proper operation? I've seen enough failed ones I'd have to imagine quite a few here are no longer functional.

Richard

 

[fancyTBI]

The 3/4 and 1 ton trucks don’t have that flap. Why would that be?

 

[L31MaxExpress]

The 3/4 and 1 ton trucks don’t have that flap. Why would that be?

I have a 454 TBI RV or G-van air cleaner that never had one either. If I can ever find the matching hensteeth larger 454 van rubber air intake duct it will go on my L31 build in the 87 G20. The duct that came with it is for a P30 and does not match the plastic elbow that goes through the core support of a G-van.

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