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I've noticed in some speedster pics that the engine is not sealed to the body to keep exhaust, etc heat away from motor. I know on VW cars this is critical to have all seals in place to avoid overheating.

Or is the speedster  body better at exhausting heat away ? If seals are not necessary that would be a bonus because they are a real bastard to install.

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So, this is not totally confirmed. My 1776 with 9:1 static compression has run flawlessly climbing up to 10,000 ft elevation in year round 85f-90f temps with less than the full engine compartment sealing.

I measure head temperature at the exhaust manifold bolt continuously with the Speeduino ECU and never see temps above 270f.  Highest engine compartment temps I measure are 155f at total heat soak.

I have the full complement of engine tin including sleds under the cylinders, but the edges of the tin are not sealed to the body. I have custom fitted stainless and rubber seals made, but I just didn't reinstall them after an engine revamp 18 months ago.

I have a large rectangle cut behind the license plate, but the firewall is solid. The engine lid had the extra Carrera style cutouts and there is no rain tray to impede airflow.

Note, this isn't a high horsepower engine with a lot of displacement. It's a modest engine built to be frisky, but to also last a long time.

I suspect if you have a bigger engine, the rule about total sealing holds. I figure mine is more like one of the dune buggy configurations where you want the essential engine tin, but a lot of the engine is just hanging out in the airflow.

I wired for three engine compartment temperature sensors recently and haven't had a chance to do the research on air temps in various locations under various conditions. Just wanted to say that it's not a given that you HAVE to do full sealing to avoid temperature problems. That said, it's not that hard and we know it can only improve things.

I think Mike has it right. A stock or near stock engine has much less cooling needs than a BIG mill.

A lot of problems with heat have to do with proper internal bearing and piston clearances, oil pump, and proper oil cooling. And don't forget which shroud/fan speed setup you have. Jetting and valve adjustment play a factor also. And don't forget proper ignition timing. Even which head casting matters, plus all the proper tins.

It all matters.

I knew nothing about VWs when I bought my first speedster in 2000.

N O T H I N G

I was a corn-fed white boy, which meant you were either a Ford guy or a GM guy (weirdos with their Mopar stuff were not part of the club). My tastes had evolved a bit since the knuckle-dragging days of the '70s, but not much. I bought the first speedster because my wife told me, "anything but a Corvette".

Cooling is just a non-issue with "normal" cars. If a hot car ran hot, we just put a thicker radiator in it. Done and done. Tuning? Pffft.

That first car was a 1776 with all the tin and whatnot and it ran HOT - like vaporlock hot. I sold that one after a year and had JPS build another one, with a very similar "100 hp" 1776. It ran hot as well.

Since then, I've had a 2210, a "200 hp" 2332, a 2276, a different 2110, a 2276 with a twin-plug and dry-sump setup, the second 2110 back for a repeat performance, and a 2234 (still on the stand waiting to go in). None of them ran as hot as either 1776.

Of course you need good surround tins. Sled tins are nice as well. The stock VW doghouse tins are reputed to be better than the 36 hp "doghouse" tin everybody sells, but I've never noticed a bunch of difference. Same with the thermostatic flaps - flaps, no flaps, there wasn't an enormous difference. I've had the Raby (now LN Engineering) DTM shrouds on everything going back to the first 2110 (except for the second 2110), and it works well, but again - it's not enough to make an enormous difference.

You know what does make an enormous difference? Two things:

  1. Heads
  2. Exhaust


Stock heads running through stock heat exchangers and a "hot-dog", EMPI Monza, or other <$100 exhaust are going to run hot. They'll run hotter than they do in a VW Beetle because the airflow through the speedster's engine compartment is pitiable. How (exactly) to get more air back there is a matter of substantial discourse (as well as the subject of lots and lots of folklore and common interweb knowledge) but it's not as big a deal as your heads and exhaust.

If a guy's car is running hot, I'd start with a better exhaust. "Better" means something tuned (4 into 1). Equal-length is better (an A1 sidewinder is not), but said Sidewinder works great. Non racer-types report good success with Vintage Speed exhausts.

... which gets us to heads, which is an entirely different conversation. Free breathing heads are better. Free breathing heads that have well considered fins are even better yet. CB's Panchitos are really hard to beat in this regard.

Tacking an oil cooler on MAY or MAY NOT help. Stan knows what he's talking about.

And by heads he's talking about much more than brand and fin makeup. He's also talking port shape and size, combustion chamber shape and size, and compression ratio.

Like I said above: it all matters.

I have a cooling setup that many say can't work well. Whatever. It's a 911 shroud modified with internal vanes and only a 96 plate cooler and thermostat. And a dry sump system, which holds about 7-8 quarts.

@356 John posted:

That's great ! Sounds like the ultimate cooling set up.

If you mean the oil setup, then no - I (mostly) didn't do it for cooling the engine. More on that later.

If you mean the rest of the engine (the entire combination, as Danny keeps saying), then yes - I'm trying pretty hard. As I said, it starts with the heads and exhaust. I just completed (but have not yet installed) a 2234, which was built with heat management as one of the main considerations.

It's got a 1-5/8" A1 sidewinder and a free-flowing exhaust - how free is something the boyz who go to the Smokys can tell you. As I keep saying, this is the place to start.

It's got CB's Panchitos, but I had them set up for beehive valvesprings to reduce the pressure, but still keep the valves under control to 7000 RPM. Less spring pressure means less friction at the tip of the valve, and especially at the cam/lifter junction. Spring pressure creates a lot more heat (and wear) than people think. The beehives have been around for years (and are proven tech) but are a new thing in the VW world, a lot of really, really smart guys on the bleeding edge of things are pretty excited about them.

I'm running AA thick-wall 92 mm cylinders and forged (not hypereutectic) pistons. The idea here is that Mahle 94 mm cylinders struggle to stay round as they get hot, and it's tough to get a good ring seal. How will they work? I've got no idea, but I'm running softer Deeves rings and a Total-Seal second to try to keep the pressure inside the cylinder and the oil out. As far as keeping the oil out, I'm also using Teflon valve-seals (which nobody does). I may regret all of this, but I've really come to hate a pressurized crankcase.

I've got 911 oil squirters that spray oil on the underside of my pistons, which is old tech the OEM guys have used for years, but which really never caught on with VW aftermarket (I believe because so much of the VW world is drag-race driven). Everybody always says, "these are oil cooled engines", which is not strictly correct generally, but in this case the oil is used as a coolant (I think of it as an aid). I've done this to pretty much every engine since the very first 2110. You need a big oil pump to make it work, and I'm not sure how useful it is - but it's doing everything you can, and I'm a belt/suspenders guy. You'll hear people say "it's not worth it", (which may be true) but never, "it doesn't work", because it does.

I did thermal coatings in the combustion chamber on the 2332 and the twin-plug 2276. NASCAR guys do this all the time, but I struggled to get anybody super-excited about doing it well for me. I'm going to chalk that up in the "probably not something I'm doing again" category. I didn't on the 2234.

I run a LN Engineering DTM shroud. This cooler incorporates a T4 oil cooler on the stand, but even when I run a 36 hp shroud, I modify it for the T4 cooler. I'm using sled tins, which need to be heavily modified to work without heat exchangers and a DTM. I'm also using all of the little enclosure tins on the front and back of the cylinders. Just doing the cooling system on the stand took a couple of months of ordering parts, modifying parts, powder-coating parts, and installing parts. No flaps (as the set-up doesn't work with flaps), but Avery's Aircooled is now making a "fixed flap" set-up that seems like a good idea if I run a 36 hp shroud on another engine.

I own/operate a small HVAC/R service business, so I know a bit about airflow. I built a nice little ring to help direct airflow on the inlet of the VW fan-wheel. It's a bit like a "velocity ring" but fit much better to the fan, although not radiused, as I don't have the capability to make a piece like that. It would work better if it were shaped as such - how much better is a subject for debate, but I'm guessing it's fractions of a percent. This was the low hanging fruit and I picked it.

A dry-sump pump requires a small crankshaft pulley, which reduces how fast the fan spins. I've got a serpentine set-up with a very small alternator pulley as well, which replicates the stock ratio. That means the fan is spinning really, really fast at high RPMs (at or near 20,000 RPM). As such, I run a welded/balanced fan on everything.

My point is that everybody asks "what can I do to improve my cooling?", when what they really mean is "what can I do that will make me feel better, but not cost a lot?". The answer is "get a better exhaust than you think you need, and get heads that flow and cool well". There's a lot you can do after that, but that's 90% of it.

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