Re: TB coolant crossover,any disadvantages?
 

See Item #4 LT5 Eliminated Systems

See Summit Racing for Aluminum Pipe Plugs.

When you install the plugs.....keep trying the plugs as you tap to make sure the final installation is about flush or out 1/16 inch and use Permatex on the plugs.. The Injector Housing Plug must be FLUSH however.

Re: TB coolant crossover,any disadvantages?
 

I had a local guy here use his metal lathe and turned some aluminum plugs tuned to match the port opening and drove them in flush with some red loctite.
Rich

Re: TB coolant crossover,any disadvantages?
 

If you bypass the TB coolant then any number of FSM recommended procedures may be effected (kludge side effects) So you'd be in that category of those that must jack the car side ways and shake and or blow air in to force coolant through or crack open the seal on the top of the water pump to get the air out and/or other work-arounds.:p
I'm just not so sure about the TB bypass. I'd be worried about blowing up a cylinder sleeve or worse if a piece of ice should form then finds it's way into the engine. But then again if you live in a freezing cold winter environment where you don't drive your car in winter or you live in a warm year round climate there'd be no issue.
I've not heard of anyone stepping up and admitting they're engine toasted and then making the connection with the TB bypass. That could be because there is no connection OR that the connection has not been associated. (for various reasons including denial).
I have to figure the engine designers would not add such a design feature as coolant to the TB without good reason. Mine is intact not RIPPED OUT :D
I wouldn't count on hearing any downside from those that have RIPPPED the TB coolant path out :p

Re: TB coolant crossover,any disadvantages?
 

Thanks Scott, I don't drive it in the winter. And we certainly have winter around here. Denial can be a dangerous and powerful thing.
I do like the cleaner look of the engine bay, and wouldn't this keep the incoming air cooler? More cooler being more better.

Cleaner look of the engine bay
 

Me also on Cleaner Look :D
No Denial here :p

1991 LT5
http://i287.photobucket.com/albums/l...510aaf14f2.jpg

1990 LT5
http://i287.photobucket.com/albums/l...b1ba5026d5.jpg


Marc has found that the throttle body (TB Coolant Blocked) has no problem with ice when the ambient temperature is at 20 degrees and the humidity is 90% :cheers:

As discussed in......Throttle Body Heat Bypass Line

Re: TB coolant crossover,any disadvantages?
 

It does indeed uncluttered the look. For me where I live winter is
mid 40s most of the time and a bit high on humidity. Perfect storm for icing. Bypassing the TB is not for everyone and it is important to be clear about that to all. There are those that would propose that it is the cure for everyone. That's just like the "snake oil" salesman approach.:p

Re: TB coolant crossover,any disadvantages?
 

I think the historic concern with icing relates to throttles sticking, learned that the hard way with carb with removed pre-heat plus winter plus open hood scoop on my old b302, pretty exciting at the time LOL. No way is a piece of ice going to cause internal damage, it is not hard enough and would not melt to make enough water to hydrolock the engine either.

I'm looking forward to dry plenum pulls, less complexity, and less weight for the race car. I know there are plenty of folks who would not/should not be modding these cars, but if my class rules allow it and it can be un-done later I'm a candidate and will continue to appreciate both sides of such discussions.

Cheers,
- Jeff

Re: TB coolant crossover,any disadvantages?
 

What did you use to cap off the coolant line on the passenger side? Was it capped on the rubber hose or the metal?

TB coolant Capped Off
 

A brass nipple that fits tight inside the rubber hose with a male 1/4 inch pipe thread and a 1/4 inch Brass pipe thread cap (female thread) ;)

I left about 2 or 3 inches of rubber hose above the "T" that connects (did connect) the TB vent, Radiator top vent, and Coolant surge container in front of passenger side (the highest point in the LT5 Coolant System).

See Tech Info - LT5 Coolant Flow Calculations

See Item #4 LT5 Eliminated Systems

See Filling With Coolant and the Air Locked Water Pump

http://i287.photobucket.com/albums/l...bcc89d832c.jpghttp://i287.photobucket.com/albums/l...555d23c965.jpg

Re: TB coolant crossover,any disadvantages?
 

Hey Jeff, wanna come up and watch, learn, help when I do this? I'm guessing multi days.
I've got a spare bedroom (good if anybody brings the wife) and two hide a beds. Anybody that comes is welcome to stay.

Re: TB coolant crossover,any disadvantages?
 

I have had a t-body coolant bypass stick at WOT before. Rev limiter til I turned the key off. Was a bad experience, almost caused an accident.
I dont do this mod anymore, at least where I live.

Re: TB coolant crossover,any disadvantages?
 

I don't understand. How does removing the coolant from the plenum or IH cause the throttle to stick?

Re: TB coolant crossover,any disadvantages?
 

Who knows? Ice in there? Getting hot coolant up there to keep the grease around the butter-fly blades in the TB soft? Those guys that designed the LT5 are probably pretty smart. There's any number of systems that could be ripped out because how/what they do is not apparent. But just like bypassing the clutch switch, you may get lucky and never find out why it's there.
When in doubt spray some "AmZoil" on it or RIP IT OUT.http://forums.corvetteforum.com/imag...ies/woohoo.gif

Re: TB coolant crossover,any disadvantages?
 

factory engineers are smarter than us. the bean counters, no so much. take for example the c4 radiator. plastic end tanks. so instead of designing a proper rad, the bean counters had lotus do the "bypass" cooling system.

think that's a smart way to go?? probably not.

as for the throttle blades icing, yes, driving it below freezing it can happen. but I've NEVER seen it. you can also drive into standing water and hydraulic a piston (that I've SEEN happen)

GM has to "idiot" proof their cars and design for ALL conditions.

but when you try and "out engineer" what GM does, it's best to understand what you are doing.

bypassing the coolant doesn't hurt anything when driving above freezing.

but it doesn't add horsepower, or save weight either. it's a "cosmetic" mod.

I tried all kinds of mods on my turbo buick to "cool the intake charge" wrapped tubin with a cooling supply around the intercooler, and intake tube, lots of rube goldberg stuff. it added weight and nothing else.

the intake charge is moving pretty fast and doesn't have much time to pick up heat. even the heat soaked intake doesn't hurt too bad, but it's certainly more of a source for intake heat that a couple inches of throttle body. ponder that one if you will.

GM mostly went to the nylon intakes on the LS motors to save weight. it worked. the intakes are smooth, flow a ton, and don't transfer engine heat to the intake charge. the high flow and smooth transitions in the intake really work.

look at the S shape of the LT5 intake. air doesn't like changing directions and turbulent flow. if we straighten out the path, we can pick up laminar flow and velocity into the port. love to have the $$$ to build a nice CF intake. hopefully I can get there soon.

Re: TB coolant crossover,any disadvantages?
 

Let me discuss this if I may :p

1. I concur with rkreigh and Hog that a freezing air flow at WOT can change the geometry of the TB as well as freeze any moisture in that area. Either could cause the TB blades to stick in any position. I am not sure if TB coolant flow heating could even keep up with WOT air flow cooling. I guess it all depends on how cold ambient temperatures actually are (are we talking 20 deg F or -20 deg F).

a. It would have been informative if Hog had just let the engine rest for a bit after turning it off to see if heat migrating upward from engine actually released the stuck TB blades.

b. Marc tested the TB function at idle at an air temperature of 20 deg F (90% Humidity) and found that the TB maintained 50 deg F temperature. This experiment is on his web site. As discussed in......Throttle Body Heat Bypass Line

c. Hog's situation is at WOT which is a completely different issue in terms of air flow and TB blade rotation.

2. The TB coolant is always flowing when the water pump impeller is rotating (except it TB coolant ports are blocked for any reason). That TB coolant flows to the "T" and to the radiator when the engine has reached operating temperatures. That TB coolant flows both ways (to radiator and coolant purge tank) when the engine is in the process of reaching operating temperatures. From this one can say........

a. TB coolant flow interferes with radiator air purging during the time the engine is in the process of reaching operating temperature.

3. Many guys and gals flush their radiators to increase radiator coolant flow. The debree/corrosion that decreased radiator coolant flow can also decrease/stop TB coolant flow (the TB coolant ports are very small).....

a. I wonder how many flush their TB coolant flow paths when they flush their radiators?

4. The additional issue that rkreigh did not mention (cosmetic mod was mentioned) is the advantages of TB blocking (actually Injector Housing Coolant Port blocked just below Plenum) for Plenum Removal......

a. With TB/Injector Housing coolant blocked you can install gaskets dry without having to concern yourself with being exposed to coolant flow. This means as in my situation I do not have to add permatex on the Plenum gasket and I do not have to torque my SS Allen Head Plenum Bolts all the way down to 19 ft-lbs.

b. This means I do not have to measure to determine when proper amount of coolant is drained to avoid potential Air Pockets (Air Locked Water Pump) when refilling with coolant.

c. What also cleans the clutter (cosmetic mod) of the LT5 is adding an Oil Catch Can (the Red Canister just in front of the Brake Fluids Reservoirs). This eliminates ALL the Plenum side rail clutter on both sides of the Plenum :thumbsup:

http://i287.photobucket.com/albums/l...d107332bc7.jpg



There.....I said it....maybe should not have said anything ;)

Re: TB coolant crossover,any disadvantages?
 

Thanks for the input, but too late, I drilled and tapped the holes last night.

Re: TB coolant crossover,any disadvantages?
 

Oh...chit :p

:cheers:

Re: TB coolant crossover,any disadvantages?
 

It's all over but the cryin' now. So far the only bad thing I've heard is the TB sticking open, and we don't know why. That's my story and I'm stickin' to it.

Re: TB coolant crossover,any disadvantages?
 

I'm sure all will be fine. And if it's not you'll not likely make any connection to bypassing the TB. And for sure you'd not likely share any side effect. I probably wouldn't either.

Let me add some mostly totally irrelevant side notes and bulky text to support my position.

1. The plenum gaskets would not stick even with the coolant going to the TB if you use 100% rubber gaskets.

2. If you know how to flush the coolant you wouldn't have any problems with clearing the TB of the MASSIVE debris that occurs there. (there is a hatch for this)

3. Coolant filling will now be an iffy job of lifting, tilting the car and shaking it so as to get air out that would have gone out as designed had you not bypassed the TB.

4. The next owner of the car will hopefully study and understand the lift and tilt routine.

5. Now you'll have some nice capped holes that look way better than stock (to some).

6. You can add some nice red paint to the plugs for extra bling [-X It'll look so cool for a year or two then... not so much.

7. You now have empty passages in the plenum that can clog with dust and debris because they are not in the coolant path.

8. You'll save $ on not having to buy replacement rubber hoses for the TB but that is irrelevant.

9. Did you know that many move the air temp sensor down to the intake filter area to avoid the heat at the metal of the plenum? Must be because during a heat soak condition the plenum gets too hot and effects the air temp reading? Imagine how much hotter it will get now with bypassing the TB.

10. The lowering of weight by losing the TB line hardware is a bit offset by adding plugs. :blahblah:

11. Did you know there is a plate at the top of the TB that can be used for cleaning the passages?

12. Actually bypassing the TB is not that big a deal on the overall. But making up a bunch of lines of text for bulk is fun. =D>


Here is an image of a stock LT5 completely intact and working.
This will become a key factor in resale value now that the car is 24yrs old (on some). Mine was built in Sept 1989 !!
It's her birthday this month.
http://www.rogerscorvette.com/spots/jan99/lt5b.jpg

Re: TB coolant crossover,any disadvantages?
 

Thanks Scott, where was all this evidence to support keeping the lines before I made the leap? BTW, I'm usually not shy. If this causes problems down the road, if I can identify it as such, I'll post up. I'm not afraid to admit when I'm wrong.

Re: TB coolant crossover,any disadvantages?
 

:cheers:

If I have ANY PROBLEMS with any of my dozens of modifications or painting I will post up also :thumbsup:

The GUY is a bit sarcastic overstating and missing many facts ;)


Oh...chit :p

Re: TB coolant crossover,any disadvantages?
 

I'm betting we can trust you will share. However, the grain of salt here is that GM had to design for all customer environments. Yours is but one. And I have not seen were any tuner has done thorough environmental testing. I still believe the most hazardous is the "cool" and relative high humidity ones not the ultra cold ones. That is just my guess.
In any event drifting too far from stock will eventually effect resale. That is a fairly well accepted axiom. Is a TB bypass too far? I actually don't think so really.
Long live the true ZR-1

Re: TB coolant crossover,any disadvantages?
 

Scott, for such a purist, I'm surprised you cut you own gaskets from rubber.

Re: TB coolant crossover,any disadvantages?
 

It's a corollary of Murphy's Law. If you prepare yourself for having to get under the plenum a lot by using a self cut gasket and not having to pay for new gaskets all the time guess what happens? You don't !
(both have to get under there and pay the $)
But that argument of being a purist sounds like it would have come from someone else.
I just resist making unsupportable mods. If it's simple enough to be seen and understood by a novice then that goal is accomplished.
I do believe in having a ZR-1 with an LT-5 in it.
Ask yourself. At what point is it no longer a ZR-1/LT5 ?
I'm not talking NCRS but
ripping things off it and bypassing systems in my opinion makes having an intact LT5 dubious. And yet a nice chrome or polished plenum adds beauty. Each of us have to make decisions about what we do and don't do to the car. The more that hack a way the more rare a true ZR-1/LT5 becomes.
Will the real ZR-1/LT5 please stand up? http://www.corvetteactioncenter.com/...ilies/gtfo.gif

Re: TB coolant crossover,any disadvantages?
 

What Did He Just Say :D :read2::rolleyes: :dontknow:

http://i287.photobucket.com/albums/l...ecrest0719.jpg


I am so confused :confused:

Re: TB coolant crossover,any disadvantages?
 

He said he thinks the value of our cars will go up some day and more origanal will be better. I think the only thing that is going to be more with my car is I'll have more fun.

Re: TB coolant crossover,any disadvantages?
 

I've had mine 16yrs. You have a bit of catching up to do in the "fun department" http://www.corvetteactioncenter.com/...ies/rocker.gif
Keep her maintained, keep her functional and keep her fun to drive.
These cars are exceptional. In that I think we can all agree.http://www.corvetteactioncenter.com/...s/grouphug.gif

Re: TB coolant crossover,any disadvantages?
 

I've got a question, I read all through the TB coolant bypass post but I can't find out what everyone did to block the vacuum line that goes to the plenum.
Did you use a piece of hose with a plug...
Looking to clean up my polished plenum.
Thanks

Re: TB coolant crossover,any disadvantages?
 

The vacuum lines need to stay, the coolant lines can go.
On that note, I came home at 17 degrees the other night. No issues that I'm aware of.

Re: TB coolant crossover,any disadvantages?
 

EXACTLY :thumbsup:

You do not eliminate any vacuum line unless you have eliminated the secondaries :D

http://i287.photobucket.com/albums/l...enumblockN.jpg

Install 1/8 inch NPT allen head pipe plugs (21/64 or 11/32 drill) two each side of Plenum (Two each TB Coolant and Injector Housing (IH) Coolant). The associated two IH coolant ports in the IH should also be plugged on each side. Total six coolant ports plugged One each side TB, One each side Plenum, One each side Injector Housing.
See Summit Racing for Aluminum Pipe Plugs.
See item 4 of LT5 Eliminated Systems

http://i287.photobucket.com/albums/l...b433b4ac6f.jpg

Re: TB coolant crossover,any disadvantages?
 

Marc says 20' F, 90% RH.

Under those conditions, I bet with hammer down (high velocity through the TB), you'd be GUARANTEED icing.

At light throttle, who knows. I'd be interested in the test procedure parameters...

Re: TB coolant crossover,any disadvantages?
 

Marc knows ;)

I would guess Marc drove the Z at all throttle positions for a test proven period of time at ambient 20 deg F with 90% humidity (the 90% humidity is pretty severe regarding icing).

Marc uses the bypass to make sure no one will come back and suggest a coolant filling technique failed because of his TB coolant elimination.

the throttle body has no problem with ice when the ambient temperature is at 20 degrees and the humidity is 90%

Marc bypasses TB coolant and I eliminate TB coolant with NO bypass with my coolant filling technique that absolutely eliminates the potential for an air locked water pump.

See Getting the Air Out Simplified TIPS

Re: TB coolant crossover,any disadvantages?
 

Thanks, yea I've been reading up on all this stuff trying to decide what to eliminate and what to leave I got confused about the vacuum line.

I was having an idle issue so I pulled the plenum. Didn't find any obvious vacuum leak. All of the plastic hoses and rubber couplers look good.
I'm going to put wire ties and silicone on all the connectors and rubber hoses.

Had my injectors flow tested, four bad injectors. Ordered new injectors from FIC.

Decided for now to remove the TB coolant hoses to dress up my polished plenum.

Re: TB coolant crossover,any disadvantages?
 

If the vacuum pump is turning on and off with the key on say every 10 seconds more or less (the vacuum pump if no leaks will actually turn on for a few seconds and then shut off for several minutes) you have a vacuum leak.

1. With plenum off disconnect the vacuum lines one at a time starting from the pump and hold your finger over the end of the vacuum line. The pump should shut off and stay off.

2. Now go to the next suspect connection and do the same.

3. Once you get just past the leaky connection, holding your finger over the end of the vacuum line will not stop the pump from recycling. You have now found the leaky connection :thumbsup:

Usually the rubber connectors leak from age (hardened rubber).

Re: TB coolant crossover,any disadvantages?
 

What do I do about the fuel pump coming on with the key on and the plenum off.
I was going to check the secondary actuators but I thought about the fuel lines being off.
Oh yea, I'm new at this.

Re: TB coolant crossover,any disadvantages?
 

Actually I think you can leave the fuel lines connected to the fuel rails and still remove Plenum.

You can check all vacuum line connections by just tipping the plenum up in front without disconnecting any DIS connectors or vacuum connections at rear of Plenum.

Re: TB coolant crossover,any disadvantages?
 

Yea but I've got mine all apart to replace injectors.
I'll check that after I put the new injectors in and connect the fuel line.

Re: TB coolant crossover,any disadvantages?
 

OOPS :D

Excellent point on turning on the key with fuel lines disconnected :thumbsup:

Oh...if you have fuel lines disconnected from the fuel rails they tend to leak fuel as fuel tank pressure (Vapor Pressure) changes in the fuel tank.
Loosen the Fuel tank cap to solve that issue.

Re: TB coolant crossover,any disadvantages?
 

I loosened my cap here Cliff, after making the same mistake on the Z, that I did with the LT1 - cap ON, and scary smell of gas on the second day (I was afraid to do anything that day even).

Cap OFF on the Z didn't get it. 4rth day, more gas :mad: :censored:

I ended up dis-connecting feed + return lines @ the tank.