Heater core bypass - Plug don't loop...

[s14unimog]

I'm just going to think out loud here for a second. Has anyone ever considered blocking, over looping, the heater inlet/outlet lines under the manifold on the SR?

A few months ago I had a leaky heater core on my Jeep Cherokee, and as a trail-side fix, I looped the lines together on the engine; effectively bypassing the core. Considering I did this years ago on my SR, I thought surely I've just bought my self an entire season of procrastination on replacing that f*cker. Well, shortly there after, my truck was having a difficult time maintaining temperature; so much in fact I ended up having it towed back to the house. Naturally, the only other option is to plug each line; considering I couldn't swap the core out quickly. So I machined a couple plugs from some aluminum stock, plugged each line and clamped them up.

Well I'll be god d*mned, the truck ran cooler than ever.... If you look at what you're doing when you loop the assembly, you're cutting out that flow valve, for one, and expediting the return trip of the hot discharge water.

Has anyone blocked their coolant lines, rather than looped them? Everyone loops them b/c its the easiest thing to do; I know I did. Is it right though?

My car doesn't over-heat regularly but doesn't exactly prefer the prolonged drift runs. Before I start changing fans, adding an expansion tank and run hoses all over my bay, I think I'm going to try blocking them and see what it does. Give me a heads up if you know something I don't.

[AVmagneticZ]

Subscribed i have the same question

[TheRealSy90]

Interested in what happens with yours. Let us know.

[s14unimog]

well, the plug I made for my bypass on the Jeep fit inside my loop hose perfect. I'm going to get some more tires on it this afternoon and see where we stand. I'll post back my results.

[onehundredoctane]

I did some research and couldn't find definitive info on water flow passages thru the SR, so I ended up just making a loop to be safe. I had originally planned to cap off all ports but noticed the top housing where the coolant temp sensor is located would only create an air pocket if water wasn't able to flow thru it. That was the biggest determining factor for me at least.

[c-los13]

interesting........
by doing this^ youll be deleting the water line that goes to the turbo correct????
how would you go about that?

[di-devol]

If he is using an s14 water neck, the return water line goes to that.

[slider2828]

One the poeople here also t'ed off this loop to feed the turbo as well.... Could that work?

[rwtf]

I did this to a KA one time, it worked fine.

[slider2828]

Really no problem?? Anyone with SR experience do this on a track car?

[didderson]

It's been such a hot summer I was considering looping mine just so the cabin doesn't get extra radiating heat in the vents.
And gold foil ins. on the firewall would also help me lol.

[huffandpuff00]

I looped mine but haven't been able to drive it yet this summer. I like the idea of looping it under the intake but i didn't feel like taking that all apart...

[s14unimog]

My Vote: PLUG don't loop.

Originally Posted by onehundredoctane

I did some research and couldn't find definitive info on water flow passages thru the SR, so I ended up just making a loop to be safe. I had originally planned to cap off all ports but noticed the top housing where the coolant temp sensor is located would only create an air pocket if water wasn't able to flow thru it. That was the biggest determining factor for me at least.

For you that might be the case b/c you've deleted the IACV lines... that would still continue flow between the lines on mine. The same would be said for the throttle body coolant lines. Looped on my car as well. You've created a different layout.

Originally Posted by slider2828

One the poeople here also t'ed off this loop to feed the turbo as well.... Could that work?

Sure. It's the same thing essentially. You're just shortening the path and removing the heat exchanger under the dash.

Originally Posted by slider2828

Really no problem?? Anyone with SR experience do this on a track car?

I went out and did some runs yesterday and last night with my new plugged setup. I essentially pushed an aluminum billet into my loop line far enough that I could reconnect.

First impressions were great. I took the car to lunch yesterday and noticed that running slow through town (10-15mph) The car maintains temperature better; instead of the up and down movement (I'm running an electronic temp gauge); plus my fan never came on. I also noticed the system did not cavitate as much. There was far less overflow than I typically see after hard drift runs. Bottom line for me is that it's staying in the system. However, I still see 190's-200*F after a prolonged drift session; but there isn't much air flow doing that. It should also be noted that I'm putting down over 400hp at the wheels and running a Koyo with a single 14" fan. I still think I need to situate an oil cooler and I might play with a surge tank if I can situate it in the bay cleanly. The PBM setup is cheap enough to try.

Originally Posted by huffandpuff00

I looped mine but haven't been able to drive it yet this summer. I like the idea of looping it under the intake but i didn't feel like taking that all apart...

Looks just like mine. Cut the s13 cross-over line down, switched to an S14 water neck and looped the assembly. It's worked great for years but the system would appreciate them being separated. Plug em.

[onehundredoctane]

Originally Posted by c-los13

interesting........
by doing this^ youll be deleting the water line that goes to the turbo correct????
how would you go about that?

Originally Posted by di-devol

If he is using an s14 water neck, the return water line goes to that.

Correct.

My set up took a beating on the dyno in 111 degree heat for 10 hours, I'd say it'd work find on the track all day. As for deleting the lines going to the iacv and tb, all that shit does is heat up the intake manifold, and we all know that hotter air isn't horsepowers best friend

[s14unimog]

If you're running an IACV though, it requires a coolant temp signal to operate correctly. Otherwise you're idling @ 1200-1500 which isn't that great for grid cool down...

I agree that you should delete the throttle body lines; as I've done.

[roboticnissan]

So by plugging the two lines that originally go to the heater core, instead of looping them, still allows water to circulate? I have an s13 kad btw.

[s14unimog]

Of course. The main supply to the block/head is the part of the thermostat housing. Not sure on a KA, but I imagine it's the same. Haven't looked a KA in years.

[c-los13]

yeah ive heard about using the water neck off an s14 sr, this is very interesting, any pic of the final wouldbe fine
also, whats the purpose on blocking the lines to the tb?

[slider2828]

Originally Posted by s14unimog

If you're running an IACV though, it requires a coolant temp signal to operate correctly. Otherwise you're idling @ 1200-1500 which isn't that great for grid cool down...

I agree that you should delete the throttle body lines; as I've done.

Awesome information.... so to sum it up....

Even if I am running IACV, I can still plug the two lines that go from the intake manifold to the heater and back.

This would still allow water to go past the coolant temp sensor?

Then I have to get a S14 water neck? because I have to plug the line that is for the water feed to the turbo in the back?

How do you loop the throttle body lines and still have a working coolant temp sensor?

Just to be clear. Thanks!

[fliprayzin240sx]

Looping > Plugging. Its better to have the coolant flowing.

[huffandpuff00]

^^I also figured it would be better to have the water moving...And allow the air to be burped easier, being loop apposed to plugged.

[Matej]

It is really tempting to plug off all the ports, but the one thing I am worried about is that it would 'pressurize' the water passages in the block more than intended, since instead of some of the water going through the side, all of it would be forced through the block instead. This same water pressure is what may account for the lower temperature, but it would most likely not be good for the motor in the long run.
I actually have no idea if that is likely or possible, I am just assuming that with my limited knowledge.

Also, when I had a KA and simplified all the lines and hoses on it, I read about people plugging their heater ports, and they reported overheating after prolonged driving. Although the KA is slightly different, and has the rear heater fitting going out of the block.


Here is the guide I used to loop the lines on my SR:
http://givemeshred.com/sr20det-coola...implification/

The guy looped all three ports. Of course, this necessitates an S14 water neck or a water neck spacer with a port if one plans to watercool the turbo.



I noticed the hardline on S14 SR's actually looks very similar to how he customized his S13 one, so I procured one to see how it would fit, and voila, it lines up perfectly.

[s14unimog]

I just noticed that I missed a lot of responses here and it could use an update. Do what you want guys, I've tracked my car for numerous track day laps and hot sessions with no cooling issues. Plug is still in place..