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View Full Version : GTM Gen2 Carwash watertight?



doug_porsche
06-23-2023, 10:31 PM
Trying to complete my car, i bought it 80% done wink wink, and...

Am I naive in trying to make the car, excluding the door windows for now, carwash watertight?

I am finding lots of places with potential water/air leaks.

Upper rollbar though the rear window bulkhead.
Lower outer seatbelt mounts.

Being just a couple of examples.

Just asking

lance corsi
06-24-2023, 11:13 AM
Lol!

beeman
06-24-2023, 12:54 PM
I think the more reasonable goal is to not get soaked if you get caught in a light rain.

Ajzride
06-24-2023, 03:03 PM
I was unable to find an incomplete GTM at a reasonable price, so I settled for an 818. Based on my experience with that factory five car.... The only hope you have of making it water tight is to completely disassemble it and build it from the ground up with that intention from the start, and be prepared for tons of customization. It is in no way from the factory capable of such a task.

lance corsi
06-24-2023, 04:33 PM
I was unable to find an incomplete GTM at a reasonable price, so I settled for an 818. Based on my experience with that factory five car.... The only hope you have of making it water tight is to completely disassemble it and build it from the ground up with that intention from the start, and be prepared for tons of customization. It is in no way from the factory capable of such a task.

Agreed!

doug_porsche
06-24-2023, 05:10 PM
Now I, and my car, feel normal!

Jim1855
06-24-2023, 08:05 PM
Can I watch? I have popcorn...
Jim

kabacj
06-26-2023, 08:03 AM
Trying to complete my car, i bought it 80% done wink wink, and...

Am I naive in trying to make the car, excluding the door windows for now, carwash watertight?

I am finding lots of places with potential water/air leaks.

Upper rollbar though the rear window bulkhead.
Lower outer seatbelt mounts.

Being just a couple of examples.

Just asking

Well considering your car is already built, it’s definitely harder, but HVAC foil tape is your friend. It’s super sticky and will make openings air and water tight.

I race in the rain with the windows open, but keeping stuff reasonably dry inside is important to prevent fogging. Tapping up the seams and openings will help.

Harder to do on an already built car but it’s possible.

wallace18
06-26-2023, 09:52 AM
Having built over 17 FFR kits including a GTM you have little to no chance of ever making one of these kit cars car wash water tight. Plus IMO you should never run one of these in a car wash. Just my 2- cents. Hope you make me eat my words but I would not bet on it, LOL. Best of luck and enjoy your GTM. :rolleyes:

crash
06-26-2023, 10:55 AM
Use light and a good "gutter seal" product. In a darkish garage use a drop light from outside the car to look for light coming through from the inside. This is easiest done with two people. One on the outside moving the light and the other on the inside marking areas where light comes through. Once all the areas are marked, decide if the HVAC tape or the gutter sealant is more appropriate(I use both) to seal the area.

We race in the rain at better than 150 MPH and have gotten it pretty well sealed. Remarkably the open windows do not have much water coming in them while at speed.

I do not believe any GTM will ever be car wash sealed.

Here's what I use.

https://www.bestmaterials.com/detail.aspx?ID=20283&msclkid=6ca50b3563a51fb5ceaa6fac83a32c41&utm_source=bing&utm_medium=cpc&utm_campaign=%5BROI%5D%20Shopping%20(Desktop)%20-%20New&utm_term=4580702892680256&utm_content=Adhesives

VRaptor SpeedWorks, LLC
06-27-2023, 11:47 AM
Trying to complete my car, i bought it 80% done wink wink, and...

Am I naive in trying to make the car, excluding the door windows for now, carwash watertight?

I am finding lots of places with potential water/air leaks.

Upper rollbar though the rear window bulkhead.
Lower outer seatbelt mounts.

Being just a couple of examples.

Just asking

When we build a car from scratch, that is always the goal. It's not that tough to do when building.....where there is a seam or gap that leads to the outside, seal it up with caulk or foil tape or weatherstrip. Yes, the door windows will always be the exception, but the rest of it really should be done anyway.....for 2 reasons.

1. If you drive on wet roads, do you want the carpet and interior to get wet and moldy? If you don't seal everything up, it will.
2. Anywhere that water can get in, so can heat and exhaust fumes (as in you example of the area around the seat belt mounts and halo tubes). If you don't seal those areas up 100%, you will get a ton of heat coming in from the engine bay. FFR provides close-out panels to seal those areas off.....but of course, they require a bit of extra work to actually seal them....again....application of tape, caulk or weatherstrip where necessary.

doug_porsche
05-27-2024, 07:45 PM
gaining on the project!
Are there any suggestions for where the rollbar enters to cockpit?
Both the A-pillars and just above your head where the rollbar exits to the engine compartment?

VRaptor SpeedWorks, LLC
05-28-2024, 08:52 AM
For the A-pillar area, I use something like dynamat for that. Clean all of the surfaces really well and stuff a piece of paper up in there (from the wheel-well side) and crease it into shape, then pull the paper out and use that as a template to cut the dynamat.....might need a few over-lapping pieces to get everything sealed. Get the dynamat up in there and seat it well with a screwdriver handle or something similar. If the bulb seal on top of the alum close-out panel that seals the wheel-well area to the body cowl area doesn't fit tight, I'll run a bead of caulk along the bulb seal to seal it up tight.

The the engine bay area, sort of depends on what there is going on for gaps in that area. If there's a long, thin gap somewhere, I might fold some foam-backed headliner in half and push it into the gap neatly to fill that. Around the halo bars, I have some foam weatherstrip here that I believe is made to close out the gable ends of a pole building to keep snow from blowing in under the rake & corner....it's about 2" x 2" in profile with self adhesive strip on one side and comes in something like a 25' or 50' roll. Even though it's 2x2, it's not very dense and you can squish it down almost flat with very little force...so the main chassis hoop behind the driver's head, I'll usually install 3 or 4 inch strips of that tight up against the window firewall panel so that when the body goes on, it squishes that foam down and also tight up against the bulb seal area above those halo bars and seals that area off from the engine bay. For the rest of those halo bars, I try to take my time when installing the roll bar padding and the headliner strips that cover the roll bars so that that headliner material squishes up tight against that firewall panel to seal it off