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cheap TB coolant bypass kit

Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Not sure if someone has mentioned this here, but Home Depot sells a very nice hose splice kit with brass 5/8" splice fitting and two hose clamps (medium-duty) for under $3. Just bought one this morning and installed it. No apparent leaks, and the fitting went in tight.
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L

LarryK 87

Guest
TB BYPASS

Just exactly what benifits does is this supposed to provide?
 
T

tom_85_vet

Guest
The car is designed to have coolant run through the TB to prevent ice. If you don't have an issue with ice, some people remove it. The theory is that if the TB runs cooler it can get a HP increase. The qestion I have, why do the after market suppliers only have kits for 92-96? If my memory is correct, it has to do with a reverse flow of the coolant.
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
On our L98 engines, there is a coolant line that runs from the coolant return hose through the throttle body and down through the block. It goes through the throttle body and back out (second hose) before going back into the block. You're running essentially 225-230+ degree coolant through your intake, which heats and expands the incoming air, which means your engine gets less air. Running the bypass will allow cooler, denser air to enter the engine and give you some small amount of a power gain. I did read on one page that if you drive your Vette in the winter cold, there's a chance this mod will allow the throttle body to ice up before the engine has had a chance to warm up. This one web site is the only place I've heard that mentioned, and I know of a number of people who have done this mod.

Essentially, you take the hose running into the TB and splice it to the hose running out of the TB. It's about a 2 on a scale of 10 work-wise (you have to undo some connectors to get access).
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Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Tom, you can get kits for 85-91 as well. TPIS had them (can't find any year's listed right now). It's simple to reverse, too, if you decide you don't want it.

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F

FordNoMore!

Guest
why buy them $20 kits ,they are aripp off, U can go to Pep boys ,or any other parts store, and go to there HELP parts isle and they have coolant adaptors for 5/8'' x 1/2'' for 2.99, it is the same thing as them aftermarket parts, only plastic instead of aluminum,( if Beer came in only platic bottles or aluminum cans, and the cans were $18 dollars more ,what would U be drinking out of),lol.....HaPpY.MoToriNg
 

jeepie

Well-known member
Joined
Feb 6, 2002
Messages
162
Location
Dunmore, Pa.
Corvette
1991 Coupe Blk/Blk
One more option for you, I just ran a new piece of 5/8 heater hose from the heater core to the engine block. No adapter, no additional connections.
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
FordNoMore, what you suggested is essentially what I'm saying, except the kit at Home Depot (for fixing garden hoses) is brass and includes hose clamps. No $20 kit needed.

Jeepie, how did you get around the need for a very sharp bend in the hose under the TB? I bought a length of hose, but it would kink every time I bent it.
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jeepie

Well-known member
Joined
Feb 6, 2002
Messages
162
Location
Dunmore, Pa.
Corvette
1991 Coupe Blk/Blk
I left enough slack when I routed it, if you pull it too tight it will kink.
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Hm. There's "stuff" in front of my TB that prevents a straighter path, unless I perhaps came up and over the MAF. Wonder if there were design changes between 86 and 91?
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jeepie

Well-known member
Joined
Feb 6, 2002
Messages
162
Location
Dunmore, Pa.
Corvette
1991 Coupe Blk/Blk
I am not sure if there is different stuff in the way. My coolant outlet sticks out from the intake under the TB and points toward the radiator, I had a lot of room there, you may have different stuff in your way. Maybe someone with a 86 who did this can answer your questions ??
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Sure, Mike. I can show you the other mods I've done recently, too. If anyone needs 1/2" connectors instead of 5/8", I've got two that were sent to me.
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Mad-Mic

Gone but not forgotten
Joined
Feb 12, 2002
Messages
1,853
Location
Annapolis Maryland
Corvette
1987 Redskin Red Coupe
Rich,

Sounds good i gotta run her thru the shop (cause i got a warranty) and get some things looked out. i'm getting a squeel like a bearing in a pulley just want to get it fixed and get them to look for fuel leaks cause i smell fuel sometimes.......then again it just might be how rich it runs?!?!?! after that we can do it.

Thanks!
Mic
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
Just lemme know when. I'm almost ready to hit the strip again anyway to see if these last mods did anything useful.
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S

sothpaw

Guest
I had the mechanic do the
bypass yesterday, since it
was their anyway for routine
maint.

He just removed the hoses to
the TB and capped off the two "T"
fittings with a heater hose cap,
like I did with the hole in my
air box.

Anyway, does anybody know if we
should cap off the TB fitting also?
My TB now has 2 open metal nipples
where the coolant hoses used to
connect!!! Is that ok? I would
imagine that coolant passage is not
connected to the air passage, so I
shouldn't get unfiltered air into
the engine...
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
See, you can do that on an LT-1. On the L98, the hose coming out of the TB goes into the block and sends coolant somewhere else important...

You can leave the TB nipples open - they just connect to each other. However, make sure you blow them out (compressed air) if you ever re-attach the hose.
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S

sothpaw

Guest
I hope it's that easy.
I worry that he should
have just connected the
2 hoses so that there would
still be a fluid passage but
that it just wouldn't go thru
the TB.

I hope that I haven't cut flow
off to some thing important.

I gotta trace the hoses tonight
and see the logic.

Temperatures were normal (180
oil and coolant) when I went
home.
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
When I looked at your engine, it appeared that the hose went from the cold side of the radiator through the TB to the hot side of the radiator with no deviations.
[RICHR]
 

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