Proper cruising RPM.

[slalombuggy]

Your problem is "aerodynamic", but not as you've been thinking about it.
To go X mph, the engine power must overcome aerodynamic drag and rolling drag. Rolling drag is about constant.The aero drag for a particular car at 65 mph is 17% more than the same car at 60 mph [(65x65)/(60x60)]. Your fan speed at 60 mph is just enough to cool the car....

60 MPH at 2400 RPM with 28" rear tires is way too tall of gearing/tire size. Normal highway cruising for a VW is 3200-3600 RPM, and where the engine is set up for it's best cooling. You can cruise a VW at those RPM's for hours and hours and hours. You need to verify the RPM's and MPH's and be within these ranges for long highway speeds.

These 2 quotes hit the nail on the head. Your engine is barely turning fast enough to keep it cool and as soon as there is more load (which generates more heat) the cooling system falls behind and your temps start to climb. Even in a buggy with it's open air design you still have to spin the fan a certain amount to pump air through the shroud and tins. And if your buggy has a big flat windshield it's going to be working the motor more than if it's a Beetle. I did nothing else to my car except remove the windshield and I gained 15mph of top end.

brad

[Skulptorchaz]

Still have not had the chance to check gauges. I think the speedo is close as I passed no one this morning. 😐
I understand what you guys are saying but, it seems like I may be on the cusp. I came into Cincy today (50 mile interstate ride) and at 65mph, it was only 200*. Granted, it was only about 75 -78 degrees out. I know a hotter temp out makes it run hotter.
So since I am somewhat close, could an auxiliary oil cooler and filter make the difference?? I know, I know, the gearing is off and the cam is too big but, tires and cam replacement are not in the budget and I already know I want the filter anyway.
Thoughts?

[slalombuggy]

The cooler will cool your oil, but what about your heads and cylinders?????? IF your oil is too hot so are they, or getting close to running hot........

brad

[Meco]

If you have a smart phone, use a speedometer app to check against your speedo. I used the app in a new vehicle just to see how it worked, then used it in my buggy.

[Skulptorchaz]

Nope, flip phone. But my buddy is bringing over his tach and dwell meter.

What about a "larger pulley" to cool the heads? I'm not even sure they make them but I have heard of a "Power Pulley". For all I know, it could be smaller. (??)

I know guys.......... I am looking for ways "around" these issues and that isn't the "BEST" way to go about it but, I just can't justify smaller tires or pulling the cam. Medical issues (in the process of losing an eye) have me struggling a bit. Plus, I wanted a relatively strong motor for "playing" (autocross, dirt drags and even on the street). I may try to mess with the timing again and see if that will give me a little relief.

BTW, coming back from Cincy yesterday, it was about 10-15* hotter and it was back to heating up again.
Also, my buggy isn't quite as bad aero-wise as most - not that it would make a whole lot of difference but, my windshield is maybe about 2/3rds the stock size and raked back. (see pix below.) I know there is more aero problems than that with a buggy but, at least it is in the right direction.

I leave Friday Morning for the dunes so I'd like do what I can before I leave. Appletree Dune buggy is real close to the dunes so if I need something that will help, I should be able to get it there.

Thank you all again for your help!!!
Chaz

[wythac]

Did you try a shorter belt yet? 500rpm increase of fan speed for 10 bucks.

That, and keeping off the interstate are the fixes within your current bandwidth and budget. If that extra mph is a problem, don't go that fast. Pretty simple and doesn't cost money. Do it. You might find you enjoy getting off the super slab. Ever heard anybody say "Yeah,that drive in the country is nice but I like the freeway soooo much better"?

[Skulptorchaz]

WYTHAC, I will be trying to get a shorter one on tomorrow. I'm skeptical I will be able to as it's pretty short now but, worth a shot. I have buddy's at the parts stores in town so I will probably do it on their lot.
I'm also not a "super slab" fan. My Knucklehead didn't care much for it either. But unfortunately, it comes close to the basic laws of physics, "Shortest distance between two points.....".
Thank you for the help. I like the way you think.

[Dr OnHolliday]

Your actual aerodynamic coefficient doesn't matter in this analysis, what matters in the calculation of the difference in drag at 2 speeds is just the 2 speeds...your aerodynamic coefficient is the same for each speed.
_________________
1965 Type 1 sunroof Baja / about 70k miles on self-rebuilt '74 1600 and counting / SP heads and aftermarket valve keepers / non-doghouse shroud with external cooler and filter / 1.5 qt extended sump / Weber 32/36 DFAV progressive carb / 009 dist with Pertronix / 1.25 ratio rockers and ball adjusters / 1.5" stainless steel J-pipes and carbon steel baja exhaust

[slalombuggy]

The Cd remains constant, but the HP (heat is a byproduct of HP) needed to increase the speed of the same vehicle increases exponentially.

At Bonneville I start the standing mile with a luke warm engine. Heads about 150F, oil about 100F, after 1.25 miles flat out my buggy had oil temps of 220F and head temps of just over 350F which quicky came down when I turned on the water spray system many of us use.

It took over 50hp to gain 5mph in the same car

brad

[yamaducci]

I had the same exact problem you are having in my buggy and seriously doubt it has anything to do with drag since it's smaller than a Bus and smaller and even lighter than a Bug. Mine turned out to be a combination of things. Since mine has a turbo that adds to some of the timing advance under boost issues but the other things to look at that I haven't seen mentioned are oil pressure pressure and control pistons and seats, Timing, and possibly tight engine (fairly new) or blow-by. If your oil gets dark fast you may have blow-by above a certain RPM. You also may be over-riding the oil piston spring over a certain RPM which will divert the oil away from your cooler. This, along with fretted seat I believe was the source of most of my engines problem.
_________________
-John Cox
My 2498 Turbo Re-Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?p=5578697#5578697

3rd Brake Light Safety Stars- I still have a couple with blue light left. Email me if interested.

[Skulptorchaz]

Hey Guys, back again.
Quick note, the Dunes are fantastic and my air cleaners suck. Pics on other thread.

I'm back to working on my cooling issues and other things. My eye surgery, before and after have slowed me down on working on it but time to "push it". I have been driving it when weather allows but, I just have to stay off the super slab.

WYTHAC,
yep, I shoe horned on a 1/2" smaller belt before I left. PLENTY tight. Hope it doesn't eat alternator bearings. And unfortunately, no diff. I rarely take the slab but, to get to Indy or Cincy, it's pretty much a must. I think we did about 5-600 miles on back roads and state roads this weekend - no slabs. I did, however, develop a leak from the higher rev's, I "think". (Other post) I'm asking about that too.

Yamaducci, I will be looking at those things now. Some have been mentioned but I just could not get to them yet. The oil does seem to get dark - maybe a little quicker - but then, it starts out kind of a darker green color. (Brad Penn oil.)
Fretted seat?? Not heard anything called that before. Bad valve seat??

Thanks for all the help gents. I'm back at it.

[wythac]

OK. Understood that you are constrained to having to address symptoms rather than the root cause(s). Cheapest way out of your dilemma would be to add a filter, thermostat block and external cooler, assuming you are tapped for full flow or can find one of those oil pump cover filters that is tapped to provide flow for a cooler. I don't know if there is such a thing. Extra sump can add 1.5 to 3 quarts but sticks out below the bottom of the car and needs protection. Adding these components increases your oil and oil cooling capacities while not addressing the reasons the heat is created.

When I had the motor I am currently running in my buggy in a bay window camper, with the aforementioned improvements, the oil capacity was nearly 7 quarts and it ran at proper temps year round in the SW desert, due to the thermostat block keeping oil from circulating thru the cooler until it was necessary.

Doing so can likely buy you time at the least investment in parts and labor...time on the road before the inability to shed the heat overcomes you cooling system, and additional time before you may have to tear the motor down due to heat related failure(s).

Pulling it over and letting it cool works too. It's all about how much time and money you want to throw at it.

[Skulptorchaz]

I am considering this:
http://www.appletreeauto.com/MESA-COOLER-KIT-48-PLATE-3081-11/
That with a sump and I hope it will be enough to keep it cool. (If it is, I still might be able to make Manx to the Middle)
Any suggestions??
Thanks guys.

[hillmotorsports]

Chaz.....
That is part of it. 2 things missing: you still need to add an oil thermostat to bypass the cooler til needed, and a fan on the cooler that will switch on when needed.

We will be at MITM without a buggy so you wouldn't be alone if you drive over in a Tintop. It will be a great opportunity to chat with some knowledgeable people from all over, see some great buggies!
_________________
Rosemarie and Paul Hill
Morrisburg, Ontario

(With way more projects than spare time!)

[Skulptorchaz]

Thanks Paul. I will also get the stat. I will wait on the fan tho. I want to see if I can strategically place the cooler in a place for optimum air going down the super slab. I will use the "yarn thing" and have a buddy drive.
I appreciate the tip on the stat!

I hear ya on the tin top. bad thing is, the "draw" is to be able to drive it. I also want to be able to drive it to So.Cal. next year. (at least it's a goal)

I was also told that a "welded fan" might help because it was wider and pushed more air. (???) Not sure I buy it but, a guy said it might help.

[didget69]

[didget69]

[vwracerdave]

You are sharpening the pencil at the wrong end. You do not need to mess with an auxillary oil cooler. You need to address your gearing and tire size. Exposed engines in buggies run cooler then engines in an enclosed engine compartment.

You don't need a welded fan for highway cruising. They are only needed for engines that see above 5500 RPM's regularly.
_________________
2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK
Featured in Dec. 2001 HOT VW's Magazine page 63

Watch my racing video's http://www.youtube.com/user/okvwracer/videos

[Skulptorchaz]

Thanks BNC and Dave.
I understand the gearing and tire ratio, as it was explained earlier. Bad thing is, I'm not going to change either. (time and money thing) So I must find a plan "B". I know the gearing and tires are the BEST way to skin this cat but there must be others. I come to you guys looking for suggestions for a "plan B".

[wythac]

Chaz, I PM'ed you. Keep lookin'.

Nothing is stopping you from doing something less than what has been suggested here but I think the folks that have posted several times want to be clear that you will be getting less (or perhaps nothing) if you do less, and don't feel comfortable providing advice that they know wont work long term.

I feel your pain but I would like you to consider the following;

The patches you are considering only buy you a little more time on the highway before even those measures will be insufficient. They will be eventually be overcome by the excess of waste heat generated by the engine. It begs the question; Why go to the trouble and additional expense if it wont accomplish what you want?

Its mid August and you don't appear to be located in year round buggy territory. Consider putting this stuff on the back burner until winter and enjoy your car until you have to stuff it in the garage for the season. You may find your choices are different when you aren't trying to patch it together to drive it tomorrow. Taking your foot off the gas is the cheapest fix and will work fine until the end of October(?). I think you just got this car on the road...and most folks take more than one season to dial in their car....just sayin'.

BTW, I just put my "street" set of rims on my car for a few weeks until I couldn't take the noise of the added RPMs at highway speed. Since my car is geared for the offroad tires, the smaller ones make for a busy engine on the highway.....but, even rapped out, it ran about 10 degrees cooler than with the larger tires, due, I am certain, to higher fan speed! Lots of fun on the launches too.