GTM #534 Build Log

[ohmygosuness]

Here's a couple more pics to help clarify the foot well situation

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[crash]

Here's a couple more pics to help clarify the foot well situation

PXL_20231101_192025077.jpg

PXL_20231101_192047382.jpg

That is interesting. Very different setup than what is on the FFR PDG GTM. Granted my GTM is very early, number 29 I believe, and the kit sheet metal may have been different at that point, or a previous owner may have changed things, but I don't believe I could run the water lines the way you have them there. Looks good the way you have it though.

Beeman, every GTM built has this hump in the radiator inlet line. It does not seem to be an issue. Again, I will also add that IMHO having a small amount of air in the system at the radiator is a minor issue. Only thing it will do is reduce the cooling ability of the radiator slightly. Not like having an air bubble where the heat is being generated, which can lead to engine failure.

[beeman]

Hi Beeman. You might be right. But if we're including the surge tank as part of the system, after relocating the tank to engine bay, the bottom of the tank is about 0.5" higher than that elbow. But, I'll still need to find a way to mount this elbow lower, somehow.

The surge tank is only going to collect air that can find its way to it, there's going to be air trapped at the upper elbow, don't know if it will be enough to screw up your cooling though. Ideally the whole system is free of any air.

[ohmygosuness]

The surge tank is only going to collect air that can find its way to it, there's going to be air trapped at the upper elbow, don't know if it will be enough to screw up your cooling though. Ideally the whole system is free of any air.

I'll keep that in mind. Might look into crash's idea of flipping the radiator 180 degree. My question is - Does it matter which side of the radiator (passenger/driver) connects to the inlet/outlet of the WP?

[ohmygosuness]

So I rotated the radiator, seems like it could work. Just need to rotate the radiator shroud, otherwise I'll have to trim it. I may need to elevate the radiator mounts a bit since that elbow is right up against the bracket.

Only thing I see is that the vent tube now becomes the drain. And the drain may become the air vent.
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[crash]

You generally want to put the hot coolant to the top of the radiator and the chilled coolant coming out the bottom. I think the new arrangement still qualifies. The only other thing might be hose diameters? Looks like they may be equal in your case?

[ohmygosuness]

You generally want to put the hot coolant to the top of the radiator and the chilled coolant coming out the bottom. I think the new arrangement still qualifies. The only other thing might be hose diameters? Looks like they may be equal in your case?

Just out of curiosity, why is that better? Is it because hot air rises and cold air drops?
With the setup I have now, the driver side port was going into the thermostat. If it's better for chilled water to coming out the bottom of the radiator, then rotating the radiator definitely helps.
Yes, both side fits a 1.25" ID coupler.

[crash]

I believe it is along the same idea but has to do with the temperature of the coolant. The hotter coolant would naturally rise and the cooler coolant would naturally fall. Thus, this would ensure that the cooled coolant is what is drawn back into the engine.

On my GTM the driver's side line is the out of engine hot line and the line that is on the thermostat side is the cool line from the radiator. Remember, the LS engine runs a "reverse" cooling system.

[ohmygosuness]

I noticed this radiator has a built-in trans fluid cooler. Now, is this going to be needed for the mendeola trans? Or should I plug them up and not use them.

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[Shoeless]

The advice I got was if you are going to track the car, best to have trans fluid cooling as well.

I'll have both engine oil and trans oil cooling on mine, but do not have the trans oil cooler in the radiator. That's just one more thing to run from the back of the car to the front.

[ohmygosuness]

The advice I got was if you are going to track the car, best to have trans fluid cooling as well.

I'll have both engine oil and trans oil cooling on mine, but do not have the trans oil cooler in the radiator. That's just one more thing to run from the back of the car to the front.

Hi Shoeless. That's a good point about running less things from the back to the front. Where is yours mounted? do you need to run another fan?

I saw the go-cart pics you posted. Looks really nice. Makes me want to work on the car even more!

[crash]

Not to open another unintended project tangent for you, but I run a heat exchanger in the water line coming out of the engine for the transaxle cooling. It is a 13 plate C&R product. This puts the transaxle heat into the water to be dissipated by the radiator, yet does not require running any more lines up to the front of the car. This is one of the reasons I upped the radiator capacity by 65% over the stock C5 radiator. This also reduces complexity in the rear of the car because it gets rid of a radiator and all of the associated ducting. Every little thing you can do to get heat out of the rear of this car and save space in the back is important. It is not a cheap alternative to a radiator in the rear, but it solves a lot of problems.

[ohmygosuness]

Not to open another unintended project tangent for you, but I run a heat exchanger in the water line coming out of the engine for the transaxle cooling. It is a 13 plate C&R product. This puts the transaxle heat into the water to be dissipated by the radiator, yet does not require running any more lines up to the front of the car. This is one of the reasons I upped the radiator capacity by 65% over the stock C5 radiator. This also reduces complexity in the rear of the car because it gets rid of a radiator and all of the associated ducting. Every little thing you can do to get heat out of the rear of this car and save space in the back is important. It is not a cheap alternative to a radiator in the rear, but it solves a lot of problems.

When I bought the GTM kit, I was prepared for a ton of "unintended" projects to come my way!
From what you just told me, I'm leaning towards using this trans cooler in the radiator. Since it's built-in, I would assume GM already included extra capacity in this radiator for cooling to account for the heat from the trans and a bigger engine on the C6 over the C5. Only thing is I believe the trans cooler is on the cold side of the radiator. And since I'm flipping the radiator 180° - unfortunately, the stock lower port becomes the upper port (which is going to be the chilled side). I hope this doesn't make a big difference in cooling.

When you said you run it in the water coming out the engine, doesn't the engine run hotter than the trans, thus, potentially heating it up?

[Shoeless]

Hi Shoeless. That's a good point about running less things from the back to the front. Where is yours mounted? do you need to run another fan?

I saw the go-cart pics you posted. Looks really nice. Makes me want to work on the car even more!

I'm using Shane's solution for mounting a couple Setrab coolers on the rear diffuser of the car. One for engine and the other for trans. I'll have about every scoop or heat abatement option that Shane has so I'll have a lot of cool air coming in and pulling heat out. Only downside is these coolers are on the diffuser and will take warm air and pull it out, so hopefully I'll manage to bring in more cool air and get hot out and it will function as intended.

If I had it to do all over again. I'd go with a full MoTeC PDM setup versus the Infinity Box setup and run a couple fans and the pump controlled by that. But that will get very expensive for you very quickly.

Glad you like the go-cart pics, this thing is so damn fun to drive!!!!!

[crash]

When I bought the GTM kit, I was prepared for a ton of "unintended" projects to come my way!
From what you just told me, I'm leaning towards using this trans cooler in the radiator. Since it's built-in, I would assume GM already included extra capacity in this radiator for cooling to account for the heat from the trans and a bigger engine on the C6 over the C5. Only thing is I believe the trans cooler is on the cold side of the radiator. And since I'm flipping the radiator 180° - unfortunately, the stock lower port becomes the upper port (which is going to be the chilled side). I hope this doesn't make a big difference in cooling.

When you said you run it in the water coming out the engine, doesn't the engine run hotter than the trans, thus, potentially heating it up?

Yes. Thermostat is a 190 and engine coolant from radiator and into engine block runs at around 190-206. I see about 225-250 or so on the trans because the exchanger is on the hot side of the engine cooling. This is fine as the transaxle used to run 275 or so without the heat exchanger and using the rear trans cooler/radiator. Mendeola recommends about 225 or so for transaxle temp so this gets us right in the ball park and much cooler than it used to run. It actually also helps warm up the transaxle as well, as when the engine coolant warms up the transaxle also sees this heat from the engine without the car moving. Not really much of an issue on a street car, but useful for a race car where we might get only one lap to get everything up to operating temperature. I run the transaxle pump whenever the ignition is on.

Unfortunately we have gotten to the point where the start up process for this race car is about an hour long thing that has to be done in the paddock before the car even moves.

[ohmygosuness]

Yes. Thermostat is a 190 and engine coolant from radiator and into engine block runs at around 190-206. I see about 225-250 or so on the trans because the exchanger is on the hot side of the engine cooling. This is fine as the transaxle used to run 275 or so without the heat exchanger and using the rear trans cooler/radiator. Mendeola recommends about 225 or so for transaxle temp so this gets us right in the ball park and much cooler than it used to run. It actually also helps warm up the transaxle as well, as when the engine coolant warms up the transaxle also sees this heat from the engine without the car moving. Not really much of an issue on a street car, but useful for a race car where we might get only one lap to get everything up to operating temperature. I run the transaxle pump whenever the ignition is on.

Unfortunately we have gotten to the point where the start up process for this race car is about an hour long thing that has to be done in the paddock before the car even moves.

If you suggest that the hot side is fine, then I'll keep it on the hot side. I have no idea how hot this trans runs.

[crash]

My thinking on this was that I wanted the transaxle heat to be in the system before it saw the radiator so that the more efficient radiator could do its job with the extra heat. If you put it on the cold side of the radiator, then there is no way to remove that extra heat until after it has gone through the engine. Probably would be fine as the thermostat would do its job as long as the coolant going to it was cool enough, but I had to choose one side or the other so I chose the hot side knowing that this transaxle had seen much hotter temperatures previously than it has seen with this setup. It was kinda a "try it and see" thing though to see how hot the transaxle would get. All seems good so far.

[ohmygosuness]

My thinking on this was that I wanted the transaxle heat to be in the system before it saw the radiator so that the more efficient radiator could do its job with the extra heat. If you put it on the cold side of the radiator, then there is no way to remove that extra heat until after it has gone through the engine. Probably would be fine as the thermostat would do its job as long as the coolant going to it was cool enough, but I had to choose one side or the other so I chose the hot side knowing that this transaxle had seen much hotter temperatures previously than it has seen with this setup. It was kinda a "try it and see" thing though to see how hot the transaxle would get. All seems good so far.

That's good enough for me. I believe you're running an LS3? That's slightly bigger than my LS2. If your trans runs cooler, I don't see why mine would run hotter. And mine would mostly be for the street.

[ohmygosuness]

debris shield.jpg

debris shield2.jpg

[crash]

Just something to think about...my shields are open on the bottom so that debris cannot be caught in them. Might not be an issue for you, but we run long races and the potential for rocks that are kicked up from the tires to lodge in with the water lines did not seem like a good idea to me, so I designed mine attaching from the top and open on the bottom.

[ohmygosuness]

I showed this to a coworker and he said the same thing about opening the bottom. That's not a problem since it's just a mock up right now.. I can definitepy close the top and open the bottom.

By the way crash, do you run an oil pump for the trans cooler?

[crash]

Yes to the pump. The big one that Tilton offers...

Tilton part number TIL-40-527

[doug_porsche]

Yes to the pump. The big one that Tilton offers...

Tilton part number TIL-40-527

I have read, but don't know so I am asking, that running the trans cooler pump all the time is actually good for lubricating some of the gear sets that get a bit lube neglected in a flipped trans. (Street car, not track car)
Is this good information or just "someone on the internet saying"?

[crash]

I guess you could say that I am just some guy on the internet, but here are the reasons I run it 100% of the time.

1) It lubes the areas of the transaxle that need to be lubed. I have a line run to the R&P and another run to the gear stack.
2) Running it all the time means that we never forget to have the lube circulating once things get busy and we hit the track surface.
3) I don't use a temperature sensor to turn on the pump because that sensor is just another potential failure point to what I consider a critical system.
4) As I was explaining earlier, because I run a heat exchanger from the trans fluid to the engine coolant, the opposite is also true. As the engine coolant warms up rapidly, because of the heat exchanger, this causes the trans to also be warmed up along with the engine...without the car even moving while we are warming it up under the tent.

I do have a shut off switch so that when we are doing things on the car like data downloads, computer adjustments, or anything else that requires the ignition to be on but the car to not actually be on the track, we don't have to listen to the pump running.

I would guess that lube distribution would be just as important or maybe more so on an inverted trans since it wasn't designed to run that way. The Tilton pumps can easily handle the lower viscosity of cold fluid without damage so I really do not see any draw backs to running it all the time, especially if you use this particular pump. If you run a radiator and a cooling fan, then I would put the fan on a temp sensor, but not the pump. There will be some pump noise, but most GTMs will drown that out with engine noise as soon as started.

Just a heads up, these pumps claim to be self priming, but in my experience they are not. Mine is mounted with the pump part of the unit BELOW the transaxle and the scavenge line a direct shot to the pump and down hill, but I still have to crack lines to get it to prime the first time after trans/pump install. Prime it and be sure fluid is flowing.

[ohmygosuness]

I'll take a better look at how I can put together the trans cooler once my Mendeola arrives. Although, I don't know when that will be. It's been 2 years and 4 months since I ordered it.

[ohmygosuness]

I may (or may not?) need to trim the top of the fan shroud.

radiator 180 piping.jpg

radiator 180.jpg

Do you guys tie these pipes down to the frame or just leave them hanging?

[crash]

They are tied down with Adel Clamps.

[ohmygosuness]

Since the radiator is flipped 180°, I have the radiator vent capped off. On the FFR manual, it said the vent tube from the cylinder head was suppose to be connected to the radiator vent. But now, can I just connect the vent tube from the cylinder head directly to the surge tank?

[VRaptor SpeedWorks, LLC]

Yes....with the reservoir mounted in the engine bay, you route the steam vent directly to the reservoir tank. With the radiator flipped, you can now use the petcock to vent all of the air out of the top of the radiator. After the first couple times you drive it, park with the front of the car downhill a bit and let it cool off and then pull the cap off of the reservoir so that the system isn't under pressure or vacuum and then open the petcock a bit to let out any air. Once you do this a couple times, you should be good to go and air really shouldn't ever be able to get into the radiator again.

[ohmygosuness]

Yes....with the reservoir mounted in the engine bay, you route the steam vent directly to the reservoir tank. With the radiator flipped, you can now use the petcock to vent all of the air out of the top of the radiator. After the first couple times you drive it, park with the front of the car downhill a bit and let it cool off and then pull the cap off of the reservoir so that the system isn't under pressure or vacuum and then open the petcock a bit to let out any air. Once you do this a couple times, you should be good to go and air really shouldn't ever be able to get into the radiator again.

Being able to start the car still feels like a dream!
Since the radiator is flipped, the vent tube is at the bottom now. I think the only place I can vent out the air is using the radiator drain plug, since it's now on top.

[beeman]

I don't recall, was there a reason you didn't use the C5 radiator?

[ohmygosuness]

I don't recall, was there a reason you didn't use the C5 radiator?

My donor is a C6. Will try to reuse as many parts from it as I can. Also, I'd prefer to use a radiator that already works with the engine from the C6.

[beeman]

C5 radiators are plentiful and cheap, might prevent some future trapped-air headaches etc. My Lingenfelter C5 ran a stock radiator with 490 NA HP LS1, ran cool.

[Shoeless]

Being able to start the car still feels like a dream!

I’ll be brutally honest here and you’ll understand once you get to that dream day of firing it up for the first time. Between now and then you will have many sleepless nights, frustrations, and challenges, but that first time you fire it up and then drive it, is TOTALY worth it. Just take it one or two steps at a time and you’ll get there !!!

[crash]

I don't know. It looks like to me this C6 radiator setup could be superior to the C5. It has the driver's side hose coming in not at the front end of the tank so interference with the hood is reduced, and the drain becoming an air bleed actually seems like a plus over the C5 arrangement. I really don't see any down sides to using this radiator.

[ohmygosuness]

C5 radiators are plentiful and cheap, might prevent some future trapped-air headaches etc. My Lingenfelter C5 ran a stock radiator with 490 NA HP LS1, ran cool.

I don't know the main difference between the C5 and C6 radiator other than the built-in trans cooler in C6 radiator. The LS2 from the C6 is 6.0 L vs LS1 being 5.7 L. I'm going to assume the C6 radiator is (maybe?) slightly larger to accommodate for the engine size. But 0.3 L may have no noticeable difference at all. If I keep running into unsolvable fitment issues, I may consider the C5 or look into Crash's radiator.

[crash]

Just a heads up on the radiator I used...it is simply a 19" X 31" GM truck radiator. The only issue with using it is that I had to weld a plate onto the radiator cap filler neck to delete the cap. If you can weld aluminum, then this isn't an issue, but if you have to take it to someone then TIG welding this block off plate on could get a bit expensive.

If I was building a street GTM I think I would stick with the C5-C6 stock radiator, and after this thread I would probably lean towards the C6 variant.

[ohmygosuness]

I forgot to mention I did not flip the fan shroud. I had to make 3 new mounting brackets on the radiator to keep the shroud at the same location, otherwise it would interfere with the hood. Not an unsolvable fitment issue, but still required some work. That just reminded me, I also need to make new mounting points for the AC coil too.

[beeman]

Trans cooler was standard on the C5 automatic transmission radiator, you probably have an auto trans c6 rad.
Crash, did you mean to say lean towards the C5 variant?

[ohmygosuness]

That I did not know. Yes, I got an automatic C6.