Chris Wilson Posted May 18, 2007 Share Posted May 18, 2007 Just had look at Graham S's car with him, and the 'tap' is definitely not accesible, so the best plan would be to put bungs into the two pipes when 'bypassing' the matrix, however the best thing of course is to replace the matrix. Correct, blank off both pipes if you are living without a heater matrix until you can (find someone daft enough to) get it changed Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 18, 2007 Author Share Posted May 18, 2007 Correct, blank off both pipes if you are living without a heater matrix until you can (find someone daft enough to) get it changed Well, digsy can now add 99.1% of things *grin*, glad to see that a few of us are in agreement.. Wonder how many people will be running out to their cars to pull off the bypass hoses that have been fitted... Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted May 18, 2007 Share Posted May 18, 2007 From non technical view, obviously people use a bit of copper pipe to get the 2 pipes to join. Surely pinching / crushing the copper pipe would cause a restriction enough. How much resriction do you need? crush the pipe in half? Gav - To make it sticky when Ian C is back can you tidy first post up a bit. Problem: , Solutions:, why etc... you get the jist you have been here long enough Quote Link to comment Share on other sites More sharing options...
JohnA Posted May 18, 2007 Share Posted May 18, 2007 Digsy you've made a good point there, coolant speed may not get too high without cavitating the pump first. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 18, 2007 Share Posted May 18, 2007 From non technical view, obviously people use a bit of copper pipe to get the 2 pipes to join. Surely pinching / crushing the copper pipe would cause a restriction enough. How much resriction do you need? crush the pipe in half? Gav - To make it sticky when Ian C is back can you tidy first post up a bit. Problem: , Solutions:, why etc... you get the jist you have been here long enough The engines obviously designed to cool perfectly with the heater matrix valve shut, so just close the pipe ends, rather than guess just HOW much of a restriction an open valve and new matrix contributes. KISS Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 18, 2007 Share Posted May 18, 2007 Race engines on stock pumps drive them slower, as the OE designers make them run at their most efficient at low RPM's for towing and the like. They almost invariably run too fast at peak RPM and above, so they tend to run bigger pulleys on them. Nissan make an N1 pump for the RB** engines, with a different impeller, for just this reason. Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted May 18, 2007 Share Posted May 18, 2007 The engines obviously designed to cool perfectly with the heater matrix valve shut, so just close the pipe ends, rather than guess just HOW much of a restriction an open valve and new matrix contributes. KISS Does the blocked pipes cause added pressure to the system for the water pump to push through though? (sorry if these are stupid questions) Quote Link to comment Share on other sites More sharing options...
TrickTT Posted May 18, 2007 Share Posted May 18, 2007 The heater uses both a coolant flow valve and an air control flap to control cabin temperature. I would have thought that due to the design of the heater matrix and control valve that the restriction created by the matrix varies between a total block (on maximum cooling - equivilent to blocking off the heater supply pipes) and zero restriction (on full heat - equivilent to bypassing the matrix). The in and out pipes of the matrix are almost directly opposite each other on one end of the header tank and are of the same size as the pipes supplying it. Whilst i am no expert on designing cooling systems, I cant see how the heater matrix (or lack of one) would effect the coolant flow in the engine outside its design parameters due to the variable nature of its operation, other than reducing the total ammount of coolant flowing in the system by about 1 litre. Edited to add: click the link in my sig for replacing your heater matrix - still available. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 18, 2007 Author Share Posted May 18, 2007 The heater uses both a coolant flow valve and an air control flap to control cabin temperature. I would have thought that due to the design of the heater matrix and control valve that the restriction created by the matrix varies between a total block (on maximum cooling - equivilent to blocking off the heater supply pipes) and zero restriction (on full heat - equivilent to bypassing the matrix). The in and out pipes of the matrix are almost directly opposite each other on one end of the header tank and are of the same size as the pipes supplying it. Whilst i am no expert on designing cooling systems, I cant see how the heater matrix (or lack of one) would effect the coolant flow in the engine outside its design parameters due to the variable nature of its operation, other than reducing the total ammount of coolant flowing in the system by about 1 litre. Edited to add: click the link in my sig for replacing your heater matrix - still available. It is the fact that the coolant will take the easiest and shortest route, and in this case this will be round the bypass pipe, resulting in a lot less cooling efficiency around the head. By design the coolant should flow mostly through the head and not round the matrix system, by removing the restriction of the matrix a lot more will flow thru the return pipe. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 18, 2007 Author Share Posted May 18, 2007 Does the blocked pipes cause added pressure to the system for the water pump to push through though? (sorry if these are stupid questions) What a blocked matrix or a blocked rad pipe?... A blocked matrix would actually be better for the engine than a bypass hose. Blocked rad pipe? well that should just be replaced. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 18, 2007 Share Posted May 18, 2007 Interesting as I have had my matrix bypassed for a very long time. What can be used to block the pipes instead and has anyone actually tried it? Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted May 18, 2007 Share Posted May 18, 2007 What can be used to block the pipes instead and has anyone actually tried it? This is the key question really Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 18, 2007 Author Share Posted May 18, 2007 Interesting as I have had my matrix bypassed for a very long time. What can be used to block the pipes instead and has anyone actually tried it? Copper bungs? Mind you I'm thinking of putting high temp copper taps on mine, just in case I need to ever block it. They aren't overly expensive and I've got a hydralics catalouge here which I'm scanning through The pressure through these hoses isn't extremely high, remember if it was REALLY high it would blow the core plugs... Around 1 to 1.2 bar roughly. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 18, 2007 Share Posted May 18, 2007 Since I have no intention of replacing the matrix I guess I could trace the pipes back and remove the excess pipework. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 18, 2007 Share Posted May 18, 2007 Just another quick question regarding this, what happens to the water sat in these pipes, surely with no where to go and just going to sit there getting hotter and hotter. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 18, 2007 Author Share Posted May 18, 2007 Since I have no intention of replacing the matrix I guess I could trace the pipes back and remove the excess pipework. Do you happen to have a infra-red thermo unit... I'd be interested to see the temp readings from the front of the head before and after you remove the excess pipe... Quote Link to comment Share on other sites More sharing options...
TrickTT Posted May 18, 2007 Share Posted May 18, 2007 It is the fact that the coolant will take the easiest and shortest route, and in this case this will be round the bypass pipe, resulting in a lot less cooling efficiency around the head. By design the coolant should flow mostly through the head and not round the matrix system, by removing the restriction of the matrix a lot more will flow thru the return pipe. I am still not convinced that having a bypass pipe will cause any less restriction than having a matrix with the water flow valve fully open. Any restriction in this case would be due to the small diameter pipes supplying the heater matrix. It used to be the case on older cars that if the coolant temp got too hot, turn the heater to full to use the heater matrix like an auxillary radiator to increase cooling. Due to its design the heater matrix acts like a trap for any crud suspended in the coolant, and the fact that the matrix has failed probably means the coolant passages in the engine are well choked up with gunk as well. I think that this, coupled with the 10% loss in coolant volume is having more effect on engine temps than a bypass pipe. Quote Link to comment Share on other sites More sharing options...
Wez Posted May 18, 2007 Share Posted May 18, 2007 Just another quick question regarding this, what happens to the water sat in these pipes id blocked, surely with no where to go the water is going to sit there getting hotter and hotter. Asking this again, not sure if people saw it Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 19, 2007 Author Share Posted May 19, 2007 Asking this again, not sure if people saw it They would be still be okay, because a) they would radiate some of the heat away and b) they would still transfer their heat down the rest of the coolant. and c) there would be some flow around them internally anyway. Quote Link to comment Share on other sites More sharing options...
JustGav Posted May 19, 2007 Author Share Posted May 19, 2007 I am still not convinced that having a bypass pipe will cause any less restriction than having a matrix with the water flow valve fully open. Any restriction in this case would be due to the small diameter pipes supplying the heater matrix. It used to be the case on older cars that if the coolant temp got too hot, turn the heater to full to use the heater matrix like an auxillary radiator to increase cooling. Due to its design the heater matrix acts like a trap for any crud suspended in the coolant, and the fact that the matrix has failed probably means the coolant passages in the engine are well choked up with gunk as well. I think that this, coupled with the 10% loss in coolant volume is having more effect on engine temps than a bypass pipe. Going to have to think about this one, might have to do some more research into this. The bit about using the matrix as a rad is still relevant on all cars, used it a few times on dodgy cars *grin* Quote Link to comment Share on other sites More sharing options...
Digsy Posted May 19, 2007 Share Posted May 19, 2007 When we run engines on a dyno there's no point in having the heater matrix in circuit. We aways replace it with a bypass pipe and a restrictor. A short run of pip short circuiting the matrix will definately have less restriction than piping the coolant to the matrix, through it and back again. Quote Link to comment Share on other sites More sharing options...
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