350TacoZilla
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Kinda surprised yo aren't required to have a solid firewall between the cab and fuel tank.
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Last Call Guest on these Group Buy Deal Items from Baja Designs
Build Tacoma 4500 build
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Malburg114
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There is behind the seats.
Easier to just quote the rule book for exactly what is needed.
2.5.5
All vehicles must have an all-metal firewall separating the occupants’ compartment from the danger of fire from the engine and fuel supply. A minimum firewall must be liquid tight and extend from body side to body side. If engine is rear-mounted, firewall must be liquid tight and extend from the driver’s shoulder height to the vehicle floor and extend from body side to body side. If rear mounted fuel cell is higher than driver’s shoulder height, a firewall between the driver and the fuel cell must extend at least 2” (50m) above the top of the fuel cell. The hood is considered an extension of the firewall on front engine vehicles. Any hole placed in the firewall for structural members, lines, etc. must be kept to a minimum. The hole should not have more than 0.0625” (1.6mm) gap around the items passing through the firewall. Metallic tape must be used to seal the hole between the firewall and the item passing through the firewall. Rear mounted engines are not required to have a top mounted hood
Malburg114
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Still fighting temp issues so if anyone has any advice I’m all ears. On gradual climbs, the coolant temp just gradually climbs. Did 22 miles today. If the trails flat, in a wash. Up and down. Small hills. Downhill. Truck stays cool. Going back to the house (gradual uphill 2 track, kind of lose and some sections are in a wash) it just starts climbing in temp. I stopped at 220 today and by the time I unbuckled and got out and walked around it once checking th tires, it had already cooled off to 195. If I’m over 3000 rpm’s it heats up faster.
fans are 12” and move about 1250 cfm each. 180 degree thermostat. No windshield etc.
Only thing I can think is not enough air flow and in the extra cab windows add some scoops to funnel more air to the radiator since the seats/our heads block a lot.
fans are 12” and move about 1250 cfm each. 180 degree thermostat. No windshield etc.
Only thing I can think is not enough air flow and in the extra cab windows add some scoops to funnel more air to the radiator since the seats/our heads block a lot.
Malburg114
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Also fighting the temp sensor. It’s an auto meter 2640 short sweep gauge. I have their Trans temp manifold (part number 2286). Gauge is wired correctly per the diagram. And I’ve tried grounding the manifold block and not grounding but the gauge never moves. When I touch the ground at the sensor, the needle will jump a small amount but it doesn’t ever read within the numbers.
Any suggestions? Going to pull the sensor tomorrow and try hearing it with a heat gun to see if that makes it move.
Any suggestions? Going to pull the sensor tomorrow and try hearing it with a heat gun to see if that makes it move.
Malburg114
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But it runs good otherwise. Looking forward to having the shocks done. We are going to sand hollow this coming weekend. Moab ultra4 was a little to much money for 2 hours of racing so going to do battle at primm instead.
The thing makes some dust. Smoked both driver tires on a rock and put decent gouges in both side walls. They don’t leak yet.
And the bushings for the exhaust already melted an fell apart if anyone has suggestions for them. Just chasing down leaks
The thing makes some dust. Smoked both driver tires on a rock and put decent gouges in both side walls. They don’t leak yet.
And the bushings for the exhaust already melted an fell apart if anyone has suggestions for them. Just chasing down leaks
Malburg114
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Malburg114
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What brand/part number? There is no specific pressure that fans are rated at so often its comparing apples and oranges between brands. 1250 CFM in a Spal is significantly different than other brands. Since it seems to stay cool generally, I would lean towards a rad that is too small or fans aren't moving enough air.
i had an issue on a car with inaccurate temp readings. went to a long probe to get it out of the fittings and actually into the fluid, soldered a ring terminal to the body and grounded it. solved the problems. guys are kartek said they would use red loctite to seal the sensors threads instead of teflon based sealant to help. that never sat well with me, so i didnt do it
long or short probe?
why arent you using the OEM probe located in the head?
solder an ring terminal here and ground it to the chassis somewhere.
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Malburg114
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That’s what the sensor looks like when not in the 1/2 npt adapter to the manifold block.i had an issue on a car with inaccurate temp readings. went to a long probe to get it out of the fittings and actually into the fluid, soldered a ring terminal to the body and grounded it. solved the problems. guys are kartek said they would use red loctite to seal the sensors threads instead of teflon based sealant to help. that never sat well with me, so i didnt do it
long or short probe?
why arent you using the OEM probe located in the head?
solder an ring terminal here and ground it to the chassis somewhere.
This is for transmission temp. Coolant is read off the back of the block and though the Holley.
Couldn’t find an easy way to add trans temp to the Holley so added its own gauge.
I watched a video where he hose clamped a ground wire below the blue line in your picture and it worked. I did that to start and if it works I’ll do something less crude.
Malburg114
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Two of these.
I was always told fan size didn’t matter as much at speed since the Air is moving faster than the fans could push/pull. Not sure radiators the issue. It’s a 31x19 which seems to be th common size used/biggesr without going custom.
My 2 cents fwiw. The angled rear mounted radiator is tougher for air to naturally flow through compred to front mount with a directed path into the radiator. It has areas on either side for a lot of air to bypass. It might not be getting as much air as is needed, if you were counting on that rather than the forced fan air.
Probably low hanging fruit: try to block the gaps around the radiator, cage and rear cab. It should force more air while moving at speed.
Also from what I can see in the pictures, the shroud might need either a little more depth or shape to allow better flow through the areas not directly in front of the fans. Your fans do cover a good amount of the core, but either a deeper shroud and/or more powerful fans might be needed to get more air through it.
tribal4krawler
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How much timing do you have in the motor? Don’t forget that a spicy timing map will make it run significantly hotter if you’re beating on it. Looking forward to seeing this thing 100% done and racing. Looks like you’re close!
gt1guy
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The flat fan shroud isn't helping and it's causing two problems at once.
First is that the fans can only suck air through the core that is directly in front of them. That leaves a lot of core not doing much.
Second is that with the shroud so close, when at speed the air will simply pack up and try to find the path of least resistance, which means going around the sides of the radiator.
This is a shroud built by C&R. It's a good reference of what a company who does shrouds and radiators for a living comes up with. It sits much further off the back of the core.
First is that the fans can only suck air through the core that is directly in front of them. That leaves a lot of core not doing much.
Second is that with the shroud so close, when at speed the air will simply pack up and try to find the path of least resistance, which means going around the sides of the radiator.
This is a shroud built by C&R. It's a good reference of what a company who does shrouds and radiators for a living comes up with. It sits much further off the back of the core.
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Well that was an autistic rabbit hole to go down. Thanks Bebop!
Malburg114 in planning my build I was also going to use a rear mount and use the number plates as louvres to funnel more air into the radiator. Not a fully formed idea yet, but a problem I'm probably going to share with you, especially since I'm going to keep the glass on the cab for most of it's life.
Malburg114
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Going in circles. Made a few panels to funnel air into the radiator and a window scoop for the passenger extra cab window. Drove it again. It still got to 220 like normal but I pushed it to 225 and it seemed to linger between 220-225 for a while. Same thing. Once I stop it cooled back off to 190-200 extremely fast. I’ll crack the steak piers again to make sure there’s no lingering air.
If the panels stay I’ll have to add some tabs. The zip ties aren’t my favorite and it’s just to see if these work.
We are going to sand hollow for a few days so it’s staying how it is for now but not sure where to go from here.
Thinking maybe put the 160 tstat back in to start. Then I can go to higher cfm fans from spal (1800 cfm per fan vs 1250 per fan currently), and if those don’t work look at making a new shroud possibly with bigger fans or just redoing the radiator mount.
If the panels stay I’ll have to add some tabs. The zip ties aren’t my favorite and it’s just to see if these work.
We are going to sand hollow for a few days so it’s staying how it is for now but not sure where to go from here.
Thinking maybe put the 160 tstat back in to start. Then I can go to higher cfm fans from spal (1800 cfm per fan vs 1250 per fan currently), and if those don’t work look at making a new shroud possibly with bigger fans or just redoing the radiator mount.
Malburg114
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The shroud I have is from griffin for this radiator. I did not make it.The flat fan shroud isn't helping and it's causing two problems at once.
First is that the fans can only suck air through the core that is directly in front of them. That leaves a lot of core not doing much.
Second is that with the shroud so close, when at speed the air will simply pack up and try to find the path of least resistance, which means going around the sides of the radiator.
This is a shroud built by C&R. It's a good reference of what a company who does shrouds and radiators for a living comes up with. It sits much further off the back of the core.
Malburg114
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Just whatever the Holley terminator x gives it. I haven’t had it tuned yet by anyone.
93blackxj
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I dont think its a fan issue. In my experience when it is a fan/airflow issue the opposite happens. Temp tends to climb when sitting still in traffic but then go down once you start moving. I think you have a flow/volume issue. And since you have already found one issue with the radiator you have, I would be leaning toward a large pressure drop across your radiator. What water pump are you running?
I dont necessarily believe this , but I have read that it takes 16x more pressure to flow the same amount of volume in a dual pass vs single pass radiator. But I have also been told by Griffin Radiators that single vs dual pass does not effect performance. But I think that only applys if you have sufficient number and size of tubes in your radiator core.
I dont necessarily believe this , but I have read that it takes 16x more pressure to flow the same amount of volume in a dual pass vs single pass radiator. But I have also been told by Griffin Radiators that single vs dual pass does not effect performance. But I think that only applys if you have sufficient number and size of tubes in your radiator core.
CBR told me ~5% increase and that dual pass generally is selected for packaging reasons.
93blackxj
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That sounds more reasonable for a properly designed radiator. But I would imagine if you start with a radiator core that is already restrictive on flow, making it double pass would increase that exponentially.
And I have no clue what brand radiator OP is using, but the dual pass baffle not being welded in would make me very suspicious.
AgitatedPancake
Frobot
Just to pile another opinion into this discussion, I'm on the side thinking that it is a (lack of) fan problem. The ducting is probably a good thing, but you really don't have much fan on that thing. The fans you linked earlier -
SPAL Automotive USA 30101522 Spal Electric Fans | Summit Racing
In the description, they say they have a 13 amp draw. If you're running them at 13v, that's only ~169 watts per fan, so only 338 watts for both fans combined at full speed. And those are brushed fans, so they get less work done per watt than modern brushless fans. That means you have less than half the fan capacity of a lot of modern stock brushless fans. Jeep JL's come with 600 watt or 850 watt brushless fans for a rough reference, That 850 watt fan pulls ~65 amps at 13v full tilt, it's a monster. Not to say you need to reconfigure your setup to run a single big fan like that or anything, but amperage/wattage (and brushed vs brushless) is a strong indicator of how much work it can get done
And this is a badass ride. I really like the steering setup and glad ya got that dialed!
SPAL Automotive USA 30101522 Spal Electric Fans | Summit Racing
In the description, they say they have a 13 amp draw. If you're running them at 13v, that's only ~169 watts per fan, so only 338 watts for both fans combined at full speed. And those are brushed fans, so they get less work done per watt than modern brushless fans. That means you have less than half the fan capacity of a lot of modern stock brushless fans. Jeep JL's come with 600 watt or 850 watt brushless fans for a rough reference, That 850 watt fan pulls ~65 amps at 13v full tilt, it's a monster. Not to say you need to reconfigure your setup to run a single big fan like that or anything, but amperage/wattage (and brushed vs brushless) is a strong indicator of how much work it can get done
And this is a badass ride. I really like the steering setup and glad ya got that dialed!
93blackxj
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I just think if it was a fan problem it would be struggling to get the temp back down when stopped. In my experience, when it goes up under load at speed but drops quickly once stopped its a flow issue (water pump, thermostat, radiator). If it struggles to stay cool when not moving fast or fairly slow, its an airflow/fan problem. But that's just my theories based on my experience, coolant issues can be very frustrating.
AgitatedPancake
Frobot
Cooling problems can definitely be hard to pinpoint, no disagreement there. In my own experiences, I feel like even weak fans can recover at idle because the engine isn't under load and generating heat, and no torque converter pouring heat into the system. Most of the overheating problems I ran into with an undersized fan were low/mid speed but mid/high power scenarios like churning up loose trails with the torque converter unlocked and it would just outrun the fan on demand until I stopped and let it cool down, then I could carry on again until the next time I outran the fan. Put more fan on (went from Volvo fan to 850w JL brushless), and it's never gone over center again, even in identical situations
Now that's not to say flow speed definitely isn't part of it, it could be for sure. The symptoms are just familiar to some I've encountered as well, and that fan wattage is pretty low
EDIT - oops, it looks like the transmission cooling is fully decoupled from the engine cooling here, that's my bad
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350TacoZilla
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No matter what the ducting and side panels seem like they would help but I agree that you have a ton of room so no need for the flat shroud on radiator. get it stepped back a bit and funnel the air towards the fans. The bypass flaps aren't going to be effective for you probably because it isn't in the grille getting 70mph air pushed through.
Chevrolet Volts have dual brushless 12" fans so not sure if you could package more than 2 there or not or Corvette uses a larger single. 17" maybe? I can't remember for sure there. Silverado is dual too. I'm not saying to buy from these people, just want you to have easy visual of them.
Volt-> Cooling Fans Assembly for Chevy 23204068 Chevrolet Volt 2011-2015 | eBay
Corvette-> Pardon Our Interruption...
Silverado-> Pardon Our Interruption...
Chevrolet Volts have dual brushless 12" fans so not sure if you could package more than 2 there or not or Corvette uses a larger single. 17" maybe? I can't remember for sure there. Silverado is dual too. I'm not saying to buy from these people, just want you to have easy visual of them.
Volt-> Cooling Fans Assembly for Chevy 23204068 Chevrolet Volt 2011-2015 | eBay
Corvette-> Pardon Our Interruption...
Silverado-> Pardon Our Interruption...
93blackxj
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Definitely some valid points. your situation does sound more like maybe what he is experiencing and could very well be an issue. That low to mid speed range is right there on the edge of still needing the fans for enough air flow across the radiator, especially with the radiator being in the back.
Ghetto Fab.
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Are these variable speed fans? If so you might be able to adjust the ramp up rate to help. If not have you tried driving with the fans always on?
I've had vehicles with the fan temp sensors in locations that won't turn the fan on in certain load scenarios, eventually causing overheating, but cools right back down when stopped. With your rad in the back its far from the engine and there might be lag in the system trying to get it too cool down.
I've had vehicles with the fan temp sensors in locations that won't turn the fan on in certain load scenarios, eventually causing overheating, but cools right back down when stopped. With your rad in the back its far from the engine and there might be lag in the system trying to get it too cool down.
