40 replies to this topic

[ChrisA]

Is there any benefit in by-passing the heater core, outside of slight reduction of the cabin temp?

[fishguyaz]

my understanding is that it will remove that coolant that would have been in that part of the system, thus lowering the CG of the car.
I was going to do this on my car, but when i found out that it will make it so the defroster wont work anymore, i have reconsidered.
if i ever go travel somewhere and need the defroster system to work, it would suck not to have it available.

anyone know how much water this modification eliminates?

[Colby Scott]

You might want to reconsider leaving the heater core in the car. Removing it wont really lower the cabin temp that much since most of the heat comes from the exhaust anyway. The benefits of leaving it in the car are that you still have the use of your defroster and the core helps to keep your water temp down due to the discharge of heat through the core itself.

[Terry Whitlock]

By-pass is legal but removal of the heater core is not. Given the age of some of the cars there is always a risk of the heater core failing and developing a leak, so many choose the by-pass method. Maintaining the defroster capability is a counter argument to leave the heater in a functional state.

[ChrisA]

I don't buy the lowering CG argument. I mean, what are we talking about, the weight of a 16oz bottle of water? And if anything, it would move the CG forward, which we don't need, unless the weight-loss is replaced with lead..

My cage builder pretty much ran my dash bar through the defroster vents, which made me unto happy. But the windshield can still get a little flow, when the blower is on hi.

[davew]

As mentioned, it is not allowed to remove the heater core. It may be bypassed, but not removed.

With my cage design, the defroster vents are still usable, so I allways leave the heater core in the car. Untill it leaks, and then I bypass it.

Dave

[ChrisA]

Never mentioned taking out the core, as I knew that was a no, no. was just curious if there was any benefit in by-passing it. Guess I won't worry about it unless the core starts leaking, or something.

Yeah, my cage builder did somethings quiet nicely, and some others that had me saying why the heck did you do that!

[davew]

The response about removing the core was directed to this, <You might want to reconsider leaving the heater core in the car.> from Colby Scott above.

I hear that same comment often. Usually about a talented fabricator (specializing in drag or circle track racing) who is doing his one and only SM.

Dave

[ChrisA]

To pull up an old thread. When one does by-pass the heater core, what size hose do you use? 3/4" I.D. is too  loose and 5/8" is too small. Didn't see anything in-between at my local NAPA or Advanced.

[Alberto]

5/8" worked for my 1.6.  Got it from NAPA.  Plumbed it into one of Advanced Autosports small Coolant Gauge Adapter when I installed my temp gauge.

 

 

 

These pics remind me that I need to move the adapter and sending unit away from the header a bit more...

[Bench Racer]

We know NA engine temp is higher at the rear of the engine from history reading and the re-plumb kits available.

 

Do you by chance have an aftermarket temp gauge between thermostat and radiator? If so what are the temp diff?

 

Does anyone know the wide open throttle temp difference between the front and rear of the engine?

[Alberto]

We know NA engine temp is higher at the rear of the engine from history reading and the re-plumb kits available.

 

Do you by chance have an aftermarket temp gauge between thermostat and radiator? If so what are the temp diff?

 

Does anyone know the wide open throttle temp difference between the front and rear of the engine?

 

 

If you're asking me, no I do not but I am curious.

[Jeff Wasilko]

We know NA engine temp is higher at the rear of the engine from history reading and the re-plumb kits available.

 

Do you by chance have an aftermarket temp gauge between thermostat and radiator? If so what are the temp diff?

 

Does anyone know the wide open throttle temp difference between the front and rear of the engine?

I have a sensor in the outlet of the radiator, and a couple of sensors in the back of the head. I've got a springfield dyno radiator, and generally see about 20-25 degF deltaT across the radiator. Spot check of a race last fall with 100degF ambient showed 200degF at the back of the head and 178degF exiting the radiator.

[Steve Scheifler]

You have a sensor at the outlet of the radiator? I think Dave is interested in the temp at the back of the head compared to the inlet of the radiator. I would like to know as well so perhaps I'll temporarily install a second one.

[Bench Racer]

You have a sensor at the outlet of the radiator? I think Dave is interested in the temp at the back of the head compared to the inlet of the radiator. I would like to know as well so perhaps I'll temporarily install a second one.

You would be correct Steve, post the results please, thanks. 

 

Talked with Mark Meller, he did mention calibration can make the same mfg. dyno results different. Same dyno still shows pluses or minuses for changes.

 

4,000 rpm to 6,873 rpm, 8 seconds, 109 lb ft at 5,700 rpm, 127 hp at 6,800 rpm. 

[Steve Scheifler]

OK, good, thanks Dave. I will replicate that this evening but I already know I won't get anywhere near those numbers. Using 8 seconds from 3500 to 7100 I see ~111-114 corrected peak HP. Can you check the graph for HP @6200? That's where I typically do initial static tuning, which reads higher because there is nothing wasted accelerating all the rotating parts. Even that is only about 120hp, but if I do that at the max HP RPM I may well see more typical numbers. I'll do that as well.

[Bench Racer]

Mark said he would send the files. If not in a day or two I'll give him another call.

[ChrisA]

Update: I did find out that 5/8" tubing will work, just needs a little lube. However, straight tube does not like to make the 180° bend and becomes restrictive. I did find a pre-molded piece that should work.  http://www.summitrac...87617/overview/

[Alberto]

Update: I did find out that 5/8" tubing will work, just needs a little lube. However, straight tube does not like to make the 180° bend and becomes restrictive. I did find a pre-molded piece that should work.  http://www.summitrac...87617/overview/

 

Good find on that one.  

I just re-used one of the stock pre-molded hoses as pictured above.

[Mark]

This one has worked well for us on many cars: 

 

http://www.napaonlin...1666_0297059217

 

Mark