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Crossover delete set-ups

43K views 82 replies 22 participants last post by  Bubblehead93 
#1 ·
I know, this is another topic that's been beaten to death BUT, thats the problem. There's a TON of options out there and everyone says there's is the best. I'd like to hear some feedback on particular set-ups you've all encountered. I'd like to delete the coolant tank, move the thermostat to the upper hose and possibly just run a GT lower hose to the oil cooler. Opinions and pictures are welcome!
 
#2 ·
I plan on running a 94-95 radiator, MMR or on3 crossover delete with the t-stat in the upper hose, delete the oil cooler, GT lower hose, hidden moroso or similar tank for overflow. Look forward to hearing other ideas.
 
#3 · (Edited)
I like the looks of this setup.. It looks like the MMR or on3 kit.. I think the MMR kit comes with -12 and the On3 comes with -10 line.

I'm interested in other ideas as well..

I'm also interested in how folks are running the head cooling mod with a kit similar to the one below.. I suppose you could run line from the fixture near the radiator to the rear of the passenger side head then to the rear of the driver side head.

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#5 ·
I'm working on getting rid of all the hose clamps on my 2001 Cobra and converting over to AN fittings and in my view, I find that the an -12 and -an 10 upper radiator hose to be too small. For my car, I'm using an -16 for the upper hoses and an- 20 for the lower hoses.

Notice how the crossover delete setups pictured in this thread have a main upper hose from the radiator that spits off into smaller an 12 or 10 hoses. That looks like a restriction to me although the drag race guys probably won't notice a loss of cooling. For a street or road race car, I would not go smaller than an 16 for the upper hoses.
 
#7 ·
I'm working on getting rid of all the hose clamps on my 2001 Cobra and converting over to AN fittings and in my view, I find that the an -12 and -an 10 upper radiator hose to be too small. For my car, I'm using an -16 for the upper hoses and an- 20 for the lower hoses.

Notice how the crossover delete setups pictured in this thread have a main upper hose from the radiator that spits off into smaller an 12 or 10 hoses. That looks like a restriction to me although the drag race guys probably won't notice a loss of cooling. For a street or road race car, I would not go smaller than an 16 for the upper hoses.
2 AN-12 hoses total the same size as the stock 1.5" upper hose, so those wouldn't be a restriction at all. A single -16 hose is actually a 1/2" smaller in size then the stock hose. The last time I did this on my drag car I ran a -24 upper hose and a -32 lower hose. I ran 2 -12 hoses off of the head into a custom y-block, then a -24 into the radiator, then just a standard -32 hose from the outlet on the radiator into custom block adapter.
 
#6 ·
When I first did it and deleted the bypass the car on a cool night with come up to Normal temp not moving but at cruising temp with cool off to quick.
 
#9 · (Edited)
You are correct Ed, I was just doing a quick comparison. The cross sectional area of a -16 house would be about .785 and a -12 is .441. So in this case if you calculate two -12 lines we have a combined cross sectional area of .882. The stock setup is a 1.5" hose on the inlet side of the radiator with a cross sectional area of 1.76. So, in this case, using 2 -12 hoses is less then optimal compared to the stock setup, but better then using a single -16. Maybe I'm looking at this wrong. Would you happen to know the velocity and flow rate of the coolant in the system? Using this we can figure actual pressure increases and drops in the coolant system using various size AN lines or hoses.
 
#18 · (Edited)
Here is a quick and dirty table I made for AN fittings, Jim, that has hose/fitting ID's and other stuff including cross sectional areas;

Font Number Parallel Pattern Screenshot


If we use two -12 lines the area of both of them will be 0.582 square inches. A single -16 line is 0.559 square inches and a -24 is 1.35 square inches. The top radiator hose has an ID of 1.5" which falls somewhere between a -24 and a -30 line. The cross sectional area of a 1.5" ID tube is 1.77 square inches. The cross sectional area of the two 1" ID tubes coming out of each head is 1.57 square inches total. It is apparent that Ford's 1.5" ID top radiator hose exceeds the capacity of the two tubes feeding it from the front of the heads.

When you drop the hose size for the feed from the front of each head to -12 AN the cross sectional area drops to 0.291 square inches from 0.7854 square inches. This means the OEM tube flows ~2.7 times the volume of the -12 lines. An OEM 1.5" diameter top hose flows over 3X the -16 AN hose being used to replace it. Other than the obvious improvement in appearance, the AN plumbing, at least in the sizes typically used represents a reduction in flow for the engine.

When Ford began the design for the FGT one of the areas they were focussed on was the engine cooling system. Their SAE white paper targeted 100 GPM as the magic number to maintain the engine at peak power. Below is a pic from that SAE paper speaking to the issue. I will attach a copy of the complete paper at the end of this post.

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I suspect that any reduction in coolant flow for a supercharged version of our engine does no good and depending on operating environment and conditions could potentially do harm. My personal predisposition is to drive the greatest coolant flow possible and consistent with adequate cooling.

About two years ago or thereabouts, I stumbled across a firm called the Hollister Road Company down in Texas. At the time I was looking for a replacement supplier for the variable sped control I used with a Mk VIII fan. The guys down at Hollister Road Co. had one and we began a discussion about expanding the capability. I wanted it to also control my Meziere water pump.

In the end we came up with a gizmo that would control both, provide a soft start for both and seamlessly raise and lower both fan and water pump speeds to produce a constant temperature in the engine using a target temp that I had set in the gizmo. One of the very interesting design features was the removal of the t-stat and the use of a temp sensor on the engine's water outlet instead of the t-stat. This is a pic, from their site, of the gizmo click here => Elect Fan & Water Pump Controller.

I am a big fan of minimal restrictions in the cooling system, and high capacity heat exchangers to maintain adequate heat dissipation. This particular approach was very attractive for me, especially after we decided to remove the t-stat from the system entirely. Without a t-stat there is no flow restriction in the return to the radiator. Ford did something similar in terms of reducing restriction in the t-stat housing on the FGT. They speak about it in the SAE paper. The housing they designed looks to be the same or at least very similar to the housing they have for the FR500 engines.

Ed
 
#10 ·
Here is an example of the correct way to "delete" the crossover on this world challenge mustang cobra. Each cylinder head has it's own AN -16 upper coolant outlet port rather than the smaller An-12 or 10 upper hoses on the "crossover delete" kits out on the market.

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#12 ·
Here is an example of the correct way to "delete" the crossover on this world challenge mustang cobra. Each cylinder head has it's own AN -16 upper coolant outlet port rather than the smaller An-12 or 10 upper hoses on the "crossover delete" kits out on the market.

View attachment 138281
All in all, I think the size of the hose is irrelavant with the way the cooling system was designed there. I've never agreed with the thermostat in the bottom hose simply due to system flow and pressure. The way they have it set up, it has to retain heat through the radiator and then be able to open the thermostat and will keep pressure in that part of the system until the the thermostat opens. I understand that they probably have a few 3/16 holes drilled in the stat but they're still pressurising the radiator untill the coolant has enough heat, after it goes through a radiator (that is getting cooled off from airflow) before it can fully open a thermostat. So I'm not sure that is the "correct" way. I know people run it that way and haven't had any problems but I don't think that is using the cooling system to it's most effeciency.
 
#13 ·
I will say this, if you are putting the thermostat in the upper hose and removing the bypass line you best live in a climate that stays above 20*C all the time.

Up here in Canada putting the FRPP 2" coolant adaptor on the block and removing the bypass line was about the single stupidest mod I have done. I am running the meziere inline t-stat housing a 180*F t-stat with 3 holes drilled and a 1" bypass line with a valve to control flow(I had to do this because if just using the upper tstat and no bypass line I was running way to cold when going down the highway unless it was above 20*C outside(so north of 70-75*F). If you drive the car on the street you absolutley want a bypass t-stat and a bypass line!

I have been able to make mine work half ass with the valve and controlling flow, but when its 40-45*F in the morning going to work on the highway I run below 160*F. coming home sitting in traffic I will run at 190-195*F at the same valve location and down the highway at 180*F or so. So like I said if you are north of 20*C(68*F) you are probably fine, but colder than that it will not stay above 180*F on the highway with airflow across the rad.

I am going to call IPSCO this winter and see if I can get a bypass housing made and go with a FORD Mustang GT 180*F bypass t-stat. try and keep the 1" bypass line and maybe just 1 hole drilled in the tstat.

The engineer in me wants to punch old Ed in the nuts as he was pushing the FRPP piece like mad, same with the boss block cough cough Ed! I think I am going to start harassing you to engineer all angles on products a bit better :rofl: you are forgetting to engineer :smart:
 
#15 ·
I have to plead guilty as charged on some of that stuff Schyler! When Ford brought out the BOSS 5.0 block I was lulled into a sense of security by the longstanding successes they had with the FR500C engine which was the big bore using an aluminum block n/a for road racing. The simple reality of it was with a PD blower that sees instant boost the marginal but adequate gasket seal for the n/a aluminum block FR500C engines was not adequate for the PD blown applications with their instant boost. The webbing between the cylinders could not maintain a reliable combustion seal for supercharged applications.

If you run a PD blower with the BOSS 5.0 block the easiest fix to the head gasket sealing problem is the SCE ICS gaskets. The permanent fix for racing applications is the stainless o-ring in the head and the receiver groove in the block deck that I believe Jim (Helomech74) uses.

The cooling problem you experience surprises me because we have temps down here that regularly run below 20˚C (68˚F) and you currently appear to be the only one experiencing this cooling phenomena at those temps. If temperatures dropped below freezing then I would not be as surprised to see the overcooling but to see it at or below 20˚ C is atypical of the experiences of others.

If coolant is not at 180˚, the T-Stat is not open and the coolant in the block will increase in temperature until it reaches 180˚ to open the t-stat and allowing the coolant to move to the radiator to be cooled. When the t-stat is closed, other than bypass holes, there should be no coolant movement from the radiator to the engine. That allows the engine to heat the coolant in the water jackets and restart the cooling cycle.

What you are experiencing sounds like what happens when the t-stat is removed and the coolant circulates continuously. If the t-stat works properly perhaps a higher temperature t-stat would improve performance. Possibly less by-pass area could also improve the performance. By-pass area is controllable by size and number of holes drilled in the t-stat and certainly also by the bypass valve you have built into your system. I will be interested in what happens after you convert to the IPSCO housing.

I am not sure I understand the problem you are having with the FRPP coolant adapter. Is it that you feel it contributes to the engine temperature issue?

Ed
 
#14 ·
What I did to act as somewhat of s bypass is the heater core instead of going directly into the back of the pump with the metal factory pipe just routes back into the radiator after the stat. If this doesn't help on cooler nights ill reroute the outlet of the coolant line from my turbo back into the motor after the stat as well.
 
#16 ·
Ed I was teasing about nut shoting you.
I feel the larger volume of coolant that can flow now is helping cause the overcooling issue. It's a nice piece, but with 3 1/8" holes I believe I used in the Tstat and my bypass half closed on the 1" line or a bit more it's running cool on the highway. 20 degree Celsius was just a guideline it's probably fine down to say 12-14 degrees. We just have far too large of temp swings here.

I may leave my house at 6am and it's 5 degrees. Coming home its 26 degrees. I am running 165f down the highway in the am and coming home sitting in traffic it's fine and 190-195. If I open my valve to allow more fluid to bypass rad I am warmer going to work but then get up to 205-210 coming home in traffic when it's warmer out. No happy medium.

I think for the temp swings I need a bypass tstat that can constantly throttle itself to maintain my engine temp better.

The frpp piece does work and temps stay cooler but I just run too cold I may be idling or cruising around town at a good temp in cool weather but get up to 60-70mph and I drop from 180 to 150-160 depending on ambient air.
 
#17 ·
The more I look at crossover deletes, the more I rack my brain on what I want to go with... I like the 99-01 crossovers with an inline t-stat. I've seen a few turbo guys with some clean engine bays without the expansion tank.

Is it possible to run a 99-01 crossover and cap off the lower part that runs to the lower t-stat housing, then run a lower GT hose, upper t-stat and run a return to an aftermarket degass bottle?
 
#24 ·
The more I look at crossover deletes, the more I rack my brain on what I want to go with... I like the 99-01 crossovers with an inline t-stat. I've seen a few turbo guys with some clean engine bays without the expansion tank.

Is it possible to run a 99-01 crossover and cap off the lower part that runs to the lower t-stat housing, then run a lower GT hose, upper t-stat and run a return to an aftermarket degass bottle?
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I run an 01' crossover with an inline T-stat, lower gt hose w/ a T fitting for a Canton expansion tank with a cap and hose for a degas bottle. It sits where the battery use to be. With the hood closed idling in the dead of summer 95* outside it never got hotter than 185*, same with a week ago when it was 34* here at night I did the same thing and it came up to temp fine and maintained 180*. I didn't make as clean as a set-up as most of the guys because I was getting sick of seeing it sit there and I just wanted to drive it, I just didn't get it tuned in time to make any races before they stopped around here.
 
#20 ·
In summer months when it's say 10-12 degrees already in the morning it's fine but does run cooler then if you have it open. It needs additional heat from the bypass put into the system.

During the summer it barely needs much bypass. Fall and spring it needs quite a bit more.
 
#28 ·
How do you have your bypass valve plumbed Schyler? Does it take coolant from the cooling mod and return it to the radiator on the radiator side of the t-stat?

If that is the plumbing model then opening the bypass would be the equivalent of increasing the bypass area of the three holes you drilled in the t-stat. When you do this it should increase the time it takes the engine to come up to temperature, sort of like running w/o a t-stat.

The only reason for the three bypass holes is to allow a slight coolant movement across the t-stat as the engine warms up instead of dead heading against a closed t-stat. The slight flow allows the warmer coolant inside the engine to find its way to the radiator. As the coolant in the block and heads comes up to the t-stat opening temperature the small but continual movement of coolant through the bypass holes allows the t-stat to "see" the higher temperature coolant and begin to open.

When you do not run any bypass holes or the holes are too small in the t-stat, then the coolant will boil in the heads and make an underhood mess before the t-stat opens. When you open a bypass that goes from the HCM to the radiator on the radiator side of the t-stat it will slow down the rate at which the engine warms up and the operating temperature of the engine once warmed up. The reason I am interested in your plumbing layout is that your bypass seems to have the opposite effect.

The experience you had with the t-stat hitting the inside of the Meziere housing would limit coolant flow and increase engine operating temperature. The Meziere housings were made to accept Chevy t-stats but other similarly sized t-stats could work as well as long as there is no mechanical interference as you identified.

It can take two (sometimes three) t-stats to noodle out the bypass requirements for a particular engine. That said most engines of a similar design need bypasses of a similar area. When you start to determine the necessary bypass area you want to pay attention to hole area rather than hole diameter. If the engine runs hot at start up and normal once underway it is an indication the bypass hole area is too small. Running cold at start up and normal once underway means the bypass hole area is too big. Change the area by no more than 50% in each change step. If you over shoot fall back by 50% of the change and you can very quickly zero in on what the engine wants.

Ed
 
#21 ·
Schyler, didn't you get the Stewart thermostat from me?
I have to put cardboard in front of the radiator in the spring and fall. I have the same thermostat. I suspect that the three holes are too much bypass on the thermostat.
Next spring I will get a regular one and only put one hole in it to see if it works better.

BTW if you all can wait I am working on a ultimate total cooling setup that will be a full package.
 
#22 ·
Does anyone see a problem with running a 94-95 radiator? This would eliminate the need for a fill cap in the crossover delete, and one could run a aftermarket overflow tank in a hidden location. At a glance, it looks as if the 03/04 cobra fan would bolt right up, and the 03/04 cars still have the bolt holes for the 94-95 upper radiator mounts.

System would look like this:

Crossover delete with tstat in upper hose, 94-95 radiator, gt hose to block (oil cooler delete), non-pressurized overflow tank out of sight.
 
#29 · (Edited)
I will be in on that James... It be neat to have a setup with a burping hole like the factory cross over! and a spot for the Water temp.. Also I have had the issues with the temp never getting to 180 when below 60deg , and when my fan is running at the same time going 60 plus MPH on nights below that temp it wont even get above 130s turn the fan off and it barley runs 160s with 2 holes drilled in thermostat.
 
#34 ·
As of right now, I plan on deleting the oil cooler and running an 01-04 oil filter adapter and lower GT hose. Then, run a T-stat in the upper holes and drill the T-stat for the bypass and also delete the degas tank and run a small one where the battery used to be. Sound simple enough? lol
 
#38 · (Edited)
That'll work on your 01 Cobra because the alternator is in a different location. From what I read, the lower oil filter adapter needs to be modified to clear the alternator.

FRPP M-6881-C water bypass is a NICE looking piece but there long gone. I looked everywhere and can't even find a used one. Does anyone sell a block off oil cooler plate similar? Everything I see looks way to small.
 
#41 ·
That'll work on your 01 Cobra because the alternator is in a different location. From what I read, the lower oil filter adapter needs to be modified to clear the alternator.

FRPP M-6881-C water bypass is a NICE looking piece but there long gone. I looked everywhere and can't even find a used one. Does anyone sell a block off oil cooler plate similar? Everything I see looks way to small.
This will be the first part I will be making to replace this.

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I hope to get this worked out in the next couple weeks.
 
#40 ·
IMO deleting the expansion tank, relocating the t-stat and deleting the oil cooler improves the cooling system by having a more "direct" path for coolant flow while also cleaning things up in the engine bay a TON.
 
#42 ·
I had to make and extra tall outlet adapter to clear the PS Pump on my 97. I was using some extensions I made but one had a small leak and I didn't think it was strong enough.
Took about 5 hrs total design/draw adapter and cnc(vmc) body then made a 1 npt to 1.5 nipple outlet on cnc lathe. IIRC the overall height was about 4" to the oil outlet tower.
Hardest part was fitting the stock oil pressure sending unit and the aftermarket sending unit far enough apart and clearing the block.
Takes a little work but it's worth it! If I get enough time this weekend I'll take a pic.
 
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