How much cooler with front cooler?
 

Hi,

I'm going to be installing a stock trombone cooler and lines on my front cooler-less '77.

Just curious, if I have it set up properly, how much cooler should it run? Is it worth about 30 degrees? Car currently doesn't run hot at all on the street (very rarely above 210), but on the track I've seen too damn hot.

Thanks,

Dave

If you plan to track it at all (IMHO) a trombone is a waste of time. Get a proper radiator type cooler (if possible mounted in the front to expose it to as much air as possible).

My take.

Yes, it's well worth it, especially compared to the cost of rebuilding your motor :)

I had the stock trombone cooler here in South Florida and on the track it was pretty much useless. Upgraded to the later style radiator cooler mounted in the fender with a fan and the temp is stable at less than 1/2 scale. I have the fan wired to a manual switch under the dash and don't use it much other than the track. Great insurance and care for the engine!

If you really want to solve the high temp problem at the track you need to go with a front valance mounted cooler; if not you're going to follow "our" steps (i.e. trombone, 28 brass, carrera...). Do it right the first time, save some $'s, and have a piece of mind.

It seems that for ordinary road driving the trombone is fine because the factory put it in all the 930s! But the rigours of track driving require more cooling.
I was planning the upgrade also.

I hear you guys on how the radiator systems are better - but right now I'm just trying to get through a 20 minute DE in New England while keeping the temps under 240, and I can get a complete system for under $500 (the trombone part is essentially free).

I've done 2 DE's so far with this car, and only had temps go over 240-250 for one of the 8 total 20 minute sessions without any cooler at all, so I think I'm close to having enough cooling as is. This is a 160 HP 2.7, not a high HP engine.

Anyone out there know what the temp drop is with the trombone? For a stock 2.7?

I am not 100% sure, but I remember reading somewhere that the oil lines running to the front of the car were worth 10 degrees in cooling and that the trombone was another 3-4 degrees.

I noticed a 20 degree drop in track temps when I replaced my trombone with a nose mounted oil cooler.

David, it is your call, but after I mounted the Setrab up front, the temps at the track dropped 30 degrees and never seen 250's again since then (it was fairly regular with the 28 brass - forget the trombone).

The trombone won't be enough for track duty.

However, it will help. And you can put it in now, then replace with a proper cooler in the future when the funds are available. Your investment now in the plumbing to feed the cooler will be protected.

Thanks guys.

Chuck- what you've described is the plan. The trombone itself doesn't cost anything, comes with the used lines.

I'm surprised at how poor the trombone is - 3-4 degrees sounds like what I've heard to expect from the cool collar. Maybe I should put my cool collar back on.

Dave

"what the temp drop is with the trombone?"

- there is no fixed number for this, nor can there be. You would have to undertake a complete heat gain & loss analysis for the car. Rough approximations can be had tho...

Do what Chuck said. It might even be enough for some days at some tracks during certain seasons of the year. The next step would be a cooler with a lot more surface area - i.e. the 'radiator' type; next better ducting; next a central cooler with good extraction; next center + coolers in both fenders...

I have the 'radiator' type cooler in my front fender and my completely rebuild all updated 2.7 without the thermos and ss headers, it regularly runs at 180-190 temp.

I live in the mountains and on a hot summer day pulling the mountain passes at a brisk speed with the outside temp at 100, I will hit 210-215 temp. I have hit 220 but will slow her down some and the temp will come down.

Before rebuilt and cooler I would hit 240-250 pretty regular.

Hope this helps.

maybe consider getting the 'scoop' to help direct more air to your trombone.
ryan

David,

What engine cooling fan do you have? How many blades? Using the turbo fan will help a lot.

For DEs use the
“Rubbermaid Solution” it is very effective and less than $100.

Best,
Grady

That good idea will be less effective in humid areas like the East coast, down South, etc. You should still get some increment from it.

Yeah, I may give that a try, though its not dry here.

I've got the 11 blade fan.

David,

What is your engine cooling fan pulley ratio? You can easily measure it using some vernier calipers (or other) measuring the OD of the belt at the fan and crankshaft. Another useful measurement is the OD of the crank pulley. Posting some images will help also.


Yes, you are correct. Even in humid conditions the “Rubbermaid Solution” will make a significant difference if you are running 240F. I’ll speculate parts of your heads are at 500F and the exhaust air off the bottom of the heads and cylinders is above 300F in places.

Do a Pelican search on “Rubbermaid Solution.” There has been a lot of good engineering thermodynamics discussion.

Best,
Grady

Yep - phase change is a helpful thing.

Grady - your pm box is full...

my reply:
Hmmm, yes I think you're right - I wasn't thinking about air that hot -- I think about the evaporative cooling as a fix for air going into the intake. ... I shouldn't have been answering posts while in the middle of an oil change...

[quote]
Grady Clay wrote on 04-05-2006 02:06 PM:
Randy,

If he is at 240F after 20 minutes, the Rubbermaid Solution will make a huge difference even in humid climes with a 5-blade fan.

I’ll bet the air coming off the cylinders and heads under those conditions is over 300F. If you had 99% humid air at say 80F into the fan the RH of the 300F exhaust air would be in the teens or lower. Lots of room for the water’s heat of vaporization to play its role.

In the morning I’ll do the calculations.