This may be a problem for ALL 5-speed TGP/TSTE conversions...or it might just be my beast.

I decided to drive the TGP to work this morning to burn off some fuel before I went racing tomorrow. I got about 1/2 mile from my house and when I came to a stop light I had a roll of steam come out from under the hood. SCARED ME TO DEATH! I immediately turned around and went home when I saw it was not gushing out of the engine.

I put my cooling system pressure test unit on the raditor neck and proceeded to pump her up to 15 psi. I hear a drip drip drip coming from under the car. Crawled underneath and started looking.

It was coming from the braids of the downpipe! :icon_eek: How is that possible...I looked from the top down thinking it was comiong from the T-stat neck or the throttle body bypass. All was dry up top. I crawled underneath again and saw the heater core supply line going down and under the downpipe...SON OF A..... :icon_evil:

I took the piping loose from the top and took it loose at the lower fitting. Pulled it out and what did I see....A FRIKKIN PIN HOLE!

I say this is a potential problem for all converted 5-speeds because the lower supply line is connected to the auto tranny and it keeps the line away from the downpipe. On the 5-speed there is nothing to mount it to so it allows the pipe to move or just plain rub on the downpipe from vibration or motor rotation.

TAKE A LOOK AT YOUR LOWER HEATER CORE SUPPLY LINE AND CORRECT AS NECCESSARY!

Toot Toot!!!

I saw that in mine when i was installing my engine and trans so moved it away from the heat in that area  :icon_lol:

i should have mentioned it..... :icon_redface:

Well it took mine what 4 years of driving to finally wear a pin hole in it? I think I saw it when I was doing the swap but thought...eh they both move together so it shouldn't be a problem! :icon_rolleyes:

Just something that FOOKED UP my fun day tomorrow because I refuse to Jerry rig something to just get by. ;) I did look at the JB weld for about 10 seconds and thought...that will work till this weekend! :laugh:

i did not have that pipe when i turbocharged my Cutlass so i had to improvise.

i completely removed the heater block from the underside of the TB and that gave me a nice way to supply the heater core (using a 12" long heater hose to connect it).  it's the red heater hose in this pic:



heat from the crossover pipe and engine movement are not an issue.

the pipe that previously returned coolant from the old TB heater block is now capped with a 5/8" rubber bypass cap.  the heater core originally got coolant supply from a pipe that went into the LIM (right under the TB).  i cut the pipe so it's only about 5" long and put a bypass cap on that too.  definately not the best way to do it but i didn't have a choice.  as far as i know the TGP specific heater core supply pipe is discontinued and the pipe that my Cutlass used when it was NA wouldn't work with the downpipe there IIRC.  it works pretty good though.  the only problem i have is that the rubber caps need to be replaced every six months or so because they start cracking/deteriorating.

fortunately, i will be fixing this problem soon by stealing that pipe from my TSTE.  it's not going to need it anymore anyway :icon_mrgreen:

I was looking at the path like you have Josh but was afraid it would get in the way of the throttle linkage. I may do that if I can not find the hard to soft pipe that was original.

So does that improve performance because the water pump doesn't have to work as hard to move the coolant so far?? Weight loss?? Less radiating heat under the hood?? :icon_eek:












:joke: :nana: Sorry I am in one of those moods this morning! :nana: :smilielol:

I just called the dealer. They say (not my normal guy there) that it is a part number 10080351 and it is a heater pipe assembly. He said it is for a TGP after looking at it 4 times (like I said not my normal guy there). Available but would take 5 days to get it and list...not my cost...is $78.04. Normally I can cut the list in half.

I think I will try your trick Josh...did you say you capped the throttle body heater pipes? I have mine just bypassed...actually I think Luke did this car. :icon_eek: WARRANTY REPAIR! :laugh:

that part number lists $34.99 on gmpd. list is only $59.04. I have doubts that's the correct one...

Yeah I saw that on GMpartsdirect. $19.98 in shipping??? FOOK THAT! I will try Josh's fix and see what happens. :icon_cool:

Kenny, i'll try to get some pics showing my setup later.

- line that previously fed TB heater is now feeding heater core
- line that previously returned coolant from TB heater is now capped
- line that previously fed heater core is capped
- line that returns coolant from heater core is unchanged (the long one that runs along the firewall).  i bought a new one from GM (about $55 IIRC) for a '91 Cutlass NA 3.1.  it fits perfect after cutting a couple inches off the straight rubber section on the end by the waterpump.

the throttle linkage arm never comes closer than 1" away from that red heater hose so no issues there.  it's about 2.5" away from the crossover pipe so no issue there either.  the fuel lines are in the way though so they cause the heater hose to have a slight kink in mine.  i thought about bending the fuel lines but didn't want to do that.  i probably should have used a hose that was a little longer but it all works fine.  i did this last October when it started getting cold out...no way was i going through winter without a heater :laugh:

Quote from: TGPilot on May 10, 2006, 07:51:32 AM

So does that improve performance because the water pump doesn't have to work as hard to move the coolant so far?? Weight loss?? Less radiating heat under the hood?? :icon_eek:


:joke: :nana: Sorry I am in one of those moods this morning! :nana: :smilielol:

at least 15hp gain at the wheels! :laugh:

Quote from: TurboSedan on May 10, 2006, 02:37:15 PM
Kenny, i'll try to get some pics showing my setup later.

- line that previously fed TB heater is now feeding heater core
- line that previously returned coolant from TB heater is now capped
- line that previously fed heater core is capped
- line that returns coolant from heater core is unchanged (the long one that runs along the firewall).  i

I will look at things tonight. Sounds like a perfect way to do it though! ;)

I performed the Josh Mitchell Heater Core Performance Mod (officially known as the JMHCPM) last night! WOW what a difference! ;) :laugh:

Your idea worked perfectly Josh! Thanks!

I put a plug in the LIM where the heater supply pipe was. I capped the TB heater return. Ran a line from the TB to the Heater Core like you said. No problems at all...plenty of heat this morning. And seat fo the past tells me at least a .0000009 HP gain...maybe a .0000010 but I do not want to brag! ;) :laugh:

 :cheers:

i might just keep mine the way it is.  i didn't realize the TGP heater core pipe didn't have a place to bolt down with the 5-speed being in there.  i like your idea of the plug in the LIM instead of cuttting the pipe off and capping it like i did.

now ya gotta get to the track!  i'm going to try to get to the Douglas track with the Cutlass on the 22nd.

I used a 1/2" NPT plug from Advanced Auto. Put some teflon on there for good measures and no problems. I think I am going to hack and weld shut the return line running across the from of the motor. No sense to having that there if it is not doing anything. ;)

Ummm, please don't shoot me for saying this :icon_frown: and for just noticing this post :icon_redface:, I think Chris A had figured this out a while ago, and giving it some thought could see it was most likely true but knowing his thoroughness, never tried to prove it for myself, the hose going to the TB is the only one that allows water to flow around in the engine until the thermostat opens :icon_eek:.  Might be good to study this just to be sure its OK to just cap it off/the lines at the TB :icon_wink:

Jeff M