Running cool....I THINK I'VE FOUND THE ANSWER!

I just took a look at my Porsche Speedster book by Michel Thiriar and on pg. 83 you can see that the original Speedster had two extra inlets in that piece that sits below the engine grill on the deck lid, you know the piece that acts as a rain shield. My VS has only two opening to the engine compartement through that piece and the original Speedster has four as you can see on pg. 83. My VS has two openings on the left and right sides that feed the carbs but nothing that feeds the fan. The original has one opening on the top, bottom and two for the sides. The side openings are for the carbs., the top is for the fan and the bottom I speculate is for engine comp. circulation. I will modify my deck lid but before I'll get a head temp gauge to find out what the head temps are now and after. I've gotta feel this is why alot of replica Speedsters run hot.

J-P

Would love to know what you find out.

David

Jean-Paul, the "additional" holes in an origninal Speedster deck lid are not specifically for anything, that is, they all contiribute to general air flow into the engine compartment. Some Carreras also had an additional hole in the bodywork behind the rear license plate.

If you haven't already done so, read the "Knowledge" article on cooling. There are a lot of high performance engines in Speedster replicas that run cool enough with only a doghouse shroud and oil cooler. Lean jetting and/or retarded ignition timing at cruising speeds can elevate operating temperatures quite a bit, as can a too-small or restrictive exhaust system.

To quote Gene Berg, don't put a bandage on your elbow if you have a skinned knee.

(Message Edited 2/3/2003 12:56:27 PM)

Yup, I here ya George. I've not had much luck cooling either the 1914cc engine nor the 2110. I've done every possible cooling trouble shooting and have added ext. cooling (oil) and a 356 alt. pulley and still when I get the car going at highway speed during 80 deg. wheather the car gets up to 220.

By the way it's really important to make sure the gauge is accurate. I bought a VDO and found it 30 deg. off! I've got an accurate one now.

I've got good engine sealing down below and a nice big exhaust but still the car runs hot even with the ext. cooler.

My proposal is to duplicate what Porsche did by adding the same type of ventilation not just turn my head on the problem and stick a huge 911 fan on it (even though those fans look incredible). With this idea it does match your Gene Berg quote. Gene Berg likes to use the factory concepts in his mods.


To quote Gene Berg, don't put a bandage on your elbow if you have a skinned knee.

My VS does not have any way to give air to the fan and the stock genuine Speedster does. As it sits the fan does not have an air path to it like the factory did, instead only the carbs get fed. The car is air cooled, it needs air.

We will see, I'll do tests before and after and I'll let you know. Any suggestions?

J-P

So George, what else did the Carreras do to improve cooling? Maybe I could use some of these ideas. I just think that Porsche knew way more about air cooling then than I do now. I'm running an engine that's putting out more HP then that Carrera did that's why I need more air. True my fan isn't pulling as much air as the Carrera one did. I just think the car needs more air. Do you drive in hot weather? Southern Ca gets real hot at times. I hope I can figure this cooling thing out before summer. Last Fri it was 90 deg. out.

J-P

The key is designing the engine to dissipate, and blow its heat away much better...the biggest part of that is making LESS heat to have to cool...that can be done easily with a few internal mods as the engine is built.

I have the privelage of working on a 59 Carrera GT with a 547, it raced at Lemans in 61. The engine lid is exactly the same as any other speedster, but it has louvers only for the carbs. The carrera engine has alot of airflow and almost 40% more finnage than any TIengine could think about. I have pics of the engine/decklid.

Several people have cut a hole in the firewall directly opposite the fan intake and run large tubing down to the bottom of the car and seen 20 degree F oil temperature drops. Of course it should be screened to keep junk out of your engine. One guy with a 195 BHP engine in a VW that saw a 20 F temp drop with this setup also mentioned he has to plug the inlet in cool/cold weather or the engine won't get up to operating temperature.

So what your saying about that guys setup (directing air right to the fan) is that it has the potential to over cool the car, I've never had that. My cooling system was always only just able to keep up in moderate heat. I'm sure that if this person added the correct factory thermostat to the fan housing that it would cool correctly. Did this person use thermostats?

I understand Jakes comment, getting the engine right from the build is important. I just feel that sooooo many Speedster owners have the same issue, why is this? The factory Speedsters and VW's don't have these problems. People drive aircooled cars in the dessert, people install turbos with the stock does house cooler with an ext. oil cooler and that will keep the engine cool. My car runs hot and I've used two diff. engines. Same car, diff engines yet still hot.

It could be a # of combined issues however I do feel more air to the fan can't hurt unless it runs too cool in which a thermostat would solve this.

Does this guy with the air tube to the fan thing have pics.?

J-P

Jean-Paul, most owners haven't a clue as to the state of tune of their car, and most of those that do are clueless about carburetor tuning and the air/fuel ratio their car is running. Ideally a wide-band A/F meter should be used in driving conditions to determine if rejetting is necessary.

Take it to a professional and let them check it out. Weird things happen; I remember a case where a FACTORY Porsche 911 header setup was improperly assembled/welded and caused one cylinder to be severely obstructed. The car ran hotter than normal, was down on power, and it was impossible to jet the carburetor correctly on one side.

Honestly I've taken my car to so called professionals and I always end up redoing their work. I've yet to come across a mech/professional that both knew what they were doing AND take the time to really figure things out. I'm not saying I know more I'm saying I care more about my ride than they do. I'm sure you'd agree, would you let someone fiddle with your car? I gotten back from mechanics with loose bolts, senders in wrong places, tight valves, you name it and these mechanics are recomended, how?

Your right though, most poeple don't know what going on with their car. I agree with you on the carbs. and using a wideband sensor. I think I've got the carbs. right but I don't really know unless a gauge is hooked up. I also test all my gauges now as they are also suspect unless tested. Where do you get a wideband A/F meter and how can you be sure that it's accurate?

J-P

Good broad-band meters are expensive; one you can trust is around $1,400 (I have one). That is why I said a PROFESSIONAL, not some guy in a bolt-on-fix-it shop. Post your general engine build, carb type, exhaust (size and type), and jetting and I'll tell you whether or not the jetting is close to correct. Or email me the info and I'll email you back. Also what tell me what ignition advance you are running and what spark plugs (type and heat range).

I'll send some info. on my setup however I do think I'm close but agian I don't know if I'm right on. I don't think this overheating thing is related to this though as the car has always run hot with various setups, engine, diff. carbs. ect.--doesn't matter. I will get a head temp gauge, test that to make sure it's accurate then start testing the concept. I won't know what's going on unless I first test the current setup.

How do you reeeaaaallly know if your A/F meter is accurate? Have you ever tested it or do you just assume it's accurate because so and so made it? Everything has some margin of error. With a typical A/F meter sensor you can get an idea how accurate it is by testing it against a volt meter. Call me suspicious, I just feel gauges can be off even when new from reliable sources.

J-P

Jean-Paul, I also have a VS and have opened up the air passages in the engine cover. If you would like to see pictures just look in the files section under carumba 356. It seems to work well so far, but the weather hear in northern Cal. hasn't gotten hot yet. Eddie

Jean-Paul:
Just one thought in the matter of cooling.

I run a Baja Bug. The engine is entirely exposed at the rear of the car. My Baja has run through rain so bad I had to slow to 30MPH to see far enough out the windshield to drive. Air-cooled VWs can tolerate rain water no problem.

If you can remove the rain shield, you should get more air flow for the SoCal summer. Also, it does not rain in SoCal in the summer. (I lived in Pasadena, San Bernardino and San Diego.)

Thanks for your input Eddie, Alan.

Eddie, did you notice any improvement in the cooling?

J-P

Eddie, your exhaust looks pretty cool! I bet that car sounds great. Can you tell me about that setup.

Also I didn't get to see if you modified the top of the deck lid (right above the fan).

J-P

Jean-Paul, Thanks for the compliments, I described the exhaust system in this same forum about 5 topics back under" building a new exhaust". It does sound very low pitched and throaty. The engine cover mods. do allow more air to the weber 44's, an no I didn't cut the top open. Although I did consider cutting a large oval in the center of the rain tray if I need more colling this summer. I've seen this done on a real 356. Then they put screen over the hole.

I tested my broad-band A/F gauge against several new liquid cooled cars running EFI - they strive to maintain about 14.7 to 1 A/F ratio - and the gauge was spot on. I also compared readings to those from another A/F gauge. Then you judge how the car runs with the jetting that reads correctly. "Elementary, my dear Watson."

Yeah that's a good way to test esspecially if it's a newer car. What A/F monitor do you use?

Hey Jean-Paul,
This is what I've done to my Vintage partly by design and partly out of, "Oooopzzz!"
I wanted a carrera decklid with the additiona louvers 'cuz they look cool and I figured more air would get to my recently up-sized carbs.
It arrived and the paint job was lousy so I started futzin' with it. I cut out the center section below the grill and replaced it with an aluminum panel with two sets of 3" louvres top to bottom.

That alone upped the 'cool' factor looks-wise in my estimation, so I set out to the painters, got it reshot, no snout bubbles or nose hairs this time, and went to install it.

It didn't fit my opening very nicely. Same manufacturer and all but obviously, different mould or somethin'. So in pouring through old pics I saw some race cars propped their decklid open a taste at the top. I rigged mine that way with a couple mickey-mouse straps, no hinges, and some allen head screws.

Sort of funky, but in an era when expediency sometimes won out over meticulous engineering, eh, who cares?

Bottom line plenty of fresh air when the weather's good. When it cools around here I lower the lid with a different set of screws and snug it down.
MM

Re: nose hairs in the paint - my 1975 Ducati 750 SS Desmo Supersport had a fibreglass gas tank and a stripe down the side was unpainted so you had a "window gas gauge". There was a housefly in the middle of the clear section of fibreglass layup, and I later learned that some joker had laid up quite a few 750 SS tanks with flys in the clear section.

Jean-Paul,

From what I have heard from several "Bug guys", the root problem with cooling our Speedsters has to do with the fact that the exhaust is right under/by the engine and the engine compartment is poorly sealed. I had a single carb 1776 that, it turns out, was running INCREDIBLY hot. I had a 2176 built and three major modifications (in addition to a new exhaust system, external oil cooler, and doghouse shroud) were made to the car directly related to cooling.

First, the bottom of the compartment was sealed and the gaps were covered with rubber hose.

Second, vents were created between the wheel wells and the carbs in the compartment.







Third, the front of the engine lid was raised a bit with addtional nuts on the hinges creating a "louvre" effect.







You can see a few more photos of all these modifications in the cooling subfolder in my main directory... Coltons 58 Speedster.

I have had ZERO issues with cooling on a much larger engine and have run the car through its paces in the foothills around here and done some decent highway driving as well.

(Message Edited 2/4/2003 2:19:13 PM)

Colton, raising the front of the decklid is a scoop, not a louver. That has been a performance VW cooling trick for years.

Oddly enough, I've seen poorly built and tuned 1,776cc engines run quite hot and well built and tuned 2,110cc or 2,276cc engines run very cool (without an auxilliary oil cooler). Certainly sealing the engine compartment from the heat-rise from exhaust and the exhausted hot air from the cooling fan is the most improtant thing you can do, other than proper tuning and build.

It is interesting that the first Spyders (roller bearing crankshaft engines) did not run an oil cooler as oil temp was not a problem; later Spyders (plain bearing crankshaft engines) required an oil cooler.

Your vents to the fender wells on each side serve much the same function as one vent opposite the cooling fan opening which is another performance VW trick.

The late doghouse shroud and oil cooler is definitely the best cooling bang for the buck, assuming all else is correct.

Whatever works... different strokes, and all that.

(Message Edited 2/4/2003 2:45:04 PM)

Thanks Colton, Paul

Those pics are great, they really explain what you did. So I guess you guys figured the same thing, not enough air. So with these mods does your car run cooler and if so by how much. Also I like the holes in the side for the carbs, I've been thinking that myself just havn't gotten the nerve to cut into the car yet. I was actually thinking about also putting in a 250cfm engine compartment fan for boats. Those fans can put out a good deal of air, I could also install a thermostat that turns it on when the heads get to a certain temp. I know, I know more current draw on the alt. ect, it was just a thought.

Actually the best approach is to get the air for free which is what you guys did. I also thought about louvers under the grill to also keep the engine bay open and still keep out water. Do you have pics of that Paul? I bet it looks good too!

J-P

Water is gonna come into the engine compartment in the rain; you just have to live with that. There is a drain in the tin underneath the crankshaft pulley. The distributor is usually "waterproofed" by the rubber boots on the spark plug wires.

Then the only real danger is wind that blows rain into an air filter and from there through the carburetor and an open valve into a cylinder when the car is parked. If you try to start an engine that has a cylinder full of water it could cause serious damage.

I had "rain hats" on my K&N air filters but took them off as they are restrictive. These are inverted plastic shells that fit over the air cleaner element to keep out water.

(Message Edited 2/4/2003 4:43:58 PM)

I've seen the 'rain hats' for air filters but didn't know that was what they were for exactly Sort of a 'safe sex' approach;keeps water from fuckin' with your carbs.Anyway, makes sense in retrospect.

Does anyone run velocity stax, sans filters?

I'm overdue for photo updates. I'm still payin' blackmail money to Antunnes 'cuz of the last photos taken of my car (and some heavyset drunk)

I thought I'd wait until I got my mind made up on paintin' a stripe on the car, then shoot it.

George,
I'm interested in your recommendation on a quality A/F meter

a/f meter===check dawes-or-daws devices on the web. they are nothing more than an o2 sensor with milivolt actuated leds. not science.
good luck=bruce

Another good source for A/F meters is Art at A.C.E. Eng. Check out the one on the gray VW sedan in last months Hot VW.

People, please understand that there are inexpensive A/F meters that are not very accurate and have limited display range - these usually cost less than $200 and use a different O2 sensor. Broad-band A/F meters use a 4-wire O2 sensor that costs at least $150; my broad-band will work with diesel, propane, or gasoline, reads to 1/10 of 1 A/F ratio, and cost $1,495.

Jean-Paul,

Raising the decklid and adding the side air vents resulted in an additional 20 degree drop in temperature.

At the risk of asking a "stupid question"...
does the rubber gasket that Kirk puts around the lip of the engine lid opening have anything to do with reduced cooling ability? Other manufacturers (and original Speedsters) use four, circular rubber "dots" to cushion the engine lid, which does not "seal" the lid like a full gasket does.

John,

You are correct. John Steele (JPS) told me he doesn't use the rubber engine lid gasket but instead installs four dots, aka buttons, that you mentioned. By not using the weather strip gasket increases air flow into the engine compartment, which your carbs will like.

George,

I know nothing about AF meters, never messed with them, though I have been around race tracks coast to coast and wittnessed hundreds of plug chops (motorcycle road races).

The question I have is for the competent home tuner, not a performance professional, wouldn't a lesser expensive AF meter bought from a reputatble retailer, for example John @ aircooled.net, be a worthwhile addition to one's tool box? John doesn't sell junk, so I ask myself, how accurate of a reading do I need for the once or twice a year tune-up/carb adjustment?

It is my understanding that once your carbs are jetted correctly unless you change some component of the engine you are done, with the exception of balancing the two carbs with each tune-up or as needed. Yikes, $1,500 for a top of the line AF meter is a ton!

Jim, the IDF's will not cause any problems unless they're jetted incorrectly or you have vacuum leaks. The 40 IDF's will prbably have 32mm venturis and F11 emulsion tubes, so main jets of 125, air correction jets of 185, idle jets of 47.5, and 50 pump squirters would probably be very close.

Ask the shop what jetting is installed and post it along with how the car seems to run when you get a chance.

Get well soon...



(Message Edited 2/5/2003 3:42:04 PM)

All,

JP and I share the same system from CSP. I saved a few bucks as I already had a set of 1.5 boxes from a system I purchased from CB Performnance.

I purchased the steel version of CSP's system, as it has stainless in some sections from mufflers back & then the actual exhaust tubes feature life long coated aluminum coated steel. I prefered going the full SS system as our fellow owner J-P did. I have seen the SS system on a show car (VW Vert) based in the mid-cities area of DFW, owner is Jack Wenk of Black Gold VW Parts. The SS system is very handsome and I bet it looks great on J-P's car. But, at the time, the extra buckolas were not in my little personal hobby acct.

As for my system? I also think it looks awesome and returns a degree of a stock or vintage look that I like to maintain. To answer your question George; Yes, you can get to the valves with the system intact. It, of course is not the wide ope shot that you get with a traditional set-up or a merged system, BUT!, but it can be accomplished without going into an exorcised child imitation while prone on the creeper.

As for extensions? JP is correct. You will need to add a couple inches (or more depending on your pref.) onto the two inch tubes that exit at the stock VW points. Me? I chose cutting back the factory ones a bit, then purchased 2" OD Stainless and we had these grafted on at almost the base point of the curve before the run straight back. Then I used some masking and paper and silver heat paint to lightly touch up the weld points. The results are great looking IMHO. Of course you could just as easily slip on bigger tubes over the stockers...... but I like the 2" size... aggresive without looking oversized.

My car is in the shop while I recover from this surgery. Seemed like a great time to get a few things done that I would be unable to accomplish until I fully heal early March. The ICTs are going off and a pair of 40IDFs are going on (Stan I'll let you know after I see if the 40's work out the way I want, ok?), I returned to a stock shifter, ala: John Leader's, except I added a short shift kit and my matching Nardi Knob. I also added BugPack's new inline thermostat for the external cooler, as the one on it was opening a bit early according to what we could determine, making for a very long warm up on cold days to get up to good heating and operating temps. (Unlike the discussions on heat problems on the other threads, I have never had heat problems with a highly built 1776 and an external oil cooler, I think that is because of the parts/build, the R&P ratio of 3:88, keeping the carbs set (Seasonally even!), using the 4 pad system that John Leader refers to for lid sealing, using a good quality synthetic oil (no leaks-no kidding), maintaining the insulation, and keeping the plugs clean/changed, plus regular timing and valve adjustments. I don't want to seem uppity here, maybe it's just good fortune, heh? But, I know whatever I'm doing, it works... even on those 100' days here in Okrahoma. I am bit nervous that the IDFs may upset this balance, but hope that properly set up they will work out fine, plus increase perf a tad, and sound cool too.)

I will call the shop and see if they can get pics of the CSP system and send this way, if not, I promise I will post some in one and a half to two weeks when I pick her back up.

Jim Ward
OKC Recovering Speedster Nut

(Message Edited 2/5/2003 3:42:21 PM)

To John Leader on "stupid questions' my answer is sounds right as to full gaskit. NO QUESTION IS A STUPID QUESTION, NON QUESTIONING IS STUPID. I work in a chassis shop at the moment were we daily deal with fullcustom limited production 'average' 250,000$ if you will to 1,000,000$$$$$$$$ to 3. OK These people have budget margens in the millions, and can't get it right. WHY!!!!!!!!!!EGO Thanks for this site. MM

Just to let everyone know, I tested the 356 pulley vs the standard pulley setup (per Georges recomendation) and the CHT temp (just installed as of last week) shows a good 30-40 deg (F) differance between the two. The 356 pulley on the altenator is smaller thus turning the fan faster thus cooling the heads more. I'm running a 2110 and the CHT are in the low 300's @ 70 deg. ambient with the 356 and with the normal VW pulley I'm showing 340's at highway speed @ 70 deg. ambient. I've got to say that the CHT gauge really shows me what's going on. My next gauge will be of course the air fuel mixt. gauge. I will use an Autometer unit as they have the highest # of LED's so as to give me a good indication of what's up with the fuel. Those gauges are nothing more than a fancy voltmeter, an engineer of mine allready built two in just a couple of hrs. As with any gauge it's always important to test IT before you can trust the thing.

J-P

Jean-Paul, glad you tried the Porsche pulley setup; it's an inexpensive and easy way to lower engine temperatures. Just be sure to use a welded and balanced fan if you are going to rev the engine past about 5,000 RPM.