Performance engine with stock OEM VW heaterboxes

[[email protected]]

With all this talk of comparing a 35+ year old Beetle to a modern counterpart, and the opportunity to drive my Super up until yesterday with the lack of snow, I started thinking about a combo for a Beetle you could drive all year around in Western Pennsylvania. I have a set of the performance 1 1/2 heater boxes without the heat sink fins, and they worked pretty good to about 35 degrees. Since most feel the stock VW heater boxes with their crimped internal tubes creating an extra heating surface area are the best for heat, how would you build a performance engine around them? I'm not talking drag engine, but something in the 100-120hp range. Since large valve heads would be choked by the heaterbox, maybe something with a stock valved head, larger bore/stroke with a small cam? I made the mistake of thinking the afternoon temp was going to get above 40 one day this week when it only made it into the high 20's, but the engine started/ran o.k. in the morning when it was 15 with dual 40 IDF's. So, lets say dual carbed stroker with stock heater boxes. What would you build? Yeah, there is the route of a gas heater, but lets only concentrate on an engine combo, not the heater.

[66brm]

I would do something in the 1900cc range, as you say any larger valves are going to be choked, and anything over .450" lift will see diminished returns from the stock valve sizes, so a 1904cc web163 dual 40 idf 1.25:1 rocker, 019 dist, tims super stock heads or L3, and the best merged header I could find for heater boxes. Set compression around 8.5-9
_________________
Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval

[air-h2o-air]

dismantle your exhangers and weld 1/8"-3/16" steel plates to tubes and make your own fins

[bugguy1967]

X2. The stock boxes' tubing size equals to about 1 1/4". They're too small to make big gains. 80 HP or make your own boxes.
_________________
"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

[Howard 111]

Berg makes big tube heater box systems up to 1 3/4". You would have to call and see it they have any fins in them.
_________________
1973 Karmann Ghia
Turbocharged, Fuel Injected
http://www.thesamba.com/vw/forum/viewtopic.php?t=531270

[Juanito84]

Personally I'd say either make your own fins on whatever exhaust you want or skip the exhaust fins and make it a stale air heater. Put your oil cooler in the cabin too.
_________________
If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine?

[FreeBug]

1776, well-ported, stock-valve-size heads, Web 218, 40 idf with 30 mm vent, stock heater boxes and a good 1/38 merged header should get 100 hp and heat, a bit more if you work on cam choice. Others might chime in with better cam ideas... (1.4 rockers?)

Alstrup is almost there with a stock carb, after all....

My issue would be the lack of chokes in winter on the idfs, si I'm looking into the cable-operated enrichment circuits for real all-weather driving.

Or find a combo which allows 100 hp with Kads, some of those can come with chokes, no?

I ran 34 Pdsits, but best I got through them was about 80-85 hp, with28 mm veturis.

[FreeBug]

I ran a 1745 with heat, but I think a 1776 will heat better, because with the 1745, I was usually driving on the low-rpm grunt, so not spinning the fan as much...more RPM, more heat volume with stock stroke.

[youngnstudly]

Having done quite a few large tube heater box/merged header conversions, I can tell you that sneaking any kind of fin arrangement between the larger diameter tube and the factory out tin halves may not be as simple as you might think, unless the fins are really short in length and not very deep. I'm not saying it's not possible, I'm just saying it's a lot more work and things get tight inside those heater boxes really fast.

I've added 2 pieces of aluminum angle (fabricated from flat sheet) to the tubes on one set of heater boxes I did, but it required (tig) welding the angle to an aluminum tube that I sliced down the middle, and then welded together (over the steel J-tube). I did it for a friend a several years back and have no idea where those heater boxes are now, so I can't speak for how well they are holding up currently. They did produce some decent heat though.

This is a pic from the first set of heater boxes I did (fully documented) back in 2009 using 1-5/8" tube size, to give you an idea of how much room is in there. Just my 2 cents...

_________________
The economy is in a state of disaster, we have NO time for common sense!

[Brian]

Madmike, bus owner, has a 2110 with stock exhaust and drives that thing everywhere.

I think the three factors are valve size, intake size and displacement. Does big displacement with small valves to match stock exhaust equal high head temps?

Does displacement determine intake/exhaust sizing?
_________________
Wash your hands

'69 Bug
'68 Baja Truck
'71 Bug
'68 Camper

Only losers litter

[ekacpuc]

I have a 2007cc with l3 heads and a web 163 cam and idf 40s with 32mm vents and run stock heater boxes. Feels nothing like a stock motor. Revs to 5200 rpm but after that the power just falls off. It's a compromise but I like it. Tons of torque. It was in the mid 20s last week and I have bilge blowers under the seats and I was nice and toasty. Oh and I have 235/75s in the back with a stock 72 trans. Still pulls awesome. I'd spank my girlfriends 92 prelude.

Just my .02 cents

[Alstrup]

Hello.
My approach would be in the neighbourhood of 66brm´s idea (with stock heaterboxes) It is correct that the engine will be choked in rpm as also ekacpuc notice, because the stock heaterboxes simply cannot flow more than X amount of air. I have built a few 1914´s over time with ported stock heads and stock heaterboxes. It is relatively easy to get 115 hp. At 120 hp it is just about over. I have tried to "help" the engine breathe better thtough the stock heaterboxes with using a 1½" header after the heaters and then also make the first 20" of 2 & 4 1 3/8". The only real advantage with that is that over just adding a regular 1½" header is that the engine seems to run cooler. That was a bit of a surprise to me at least. The real stepped header did also make the engine pull a hairswith more rpm, but not anything worth the extra cost of making the header. I also noticed that these 1914´s do not like to cruise above approx 4500 rpm. I am assuming that it is because the torque curve takes a dive in that range too.
If you build it 1776 you will have the ability to make power a little higher in the rpm. If you build it 1914 you will get more torque in the driving rpms. You can of course also build a ministroker like a 1850,1904 or similar which will also work well. Soo, if you like to rev the engine a little you should build it smaller. If you like some torque in the driving rpms you should build it larger. But my personal opinion is that there is no idea in building it larger than approx 1900 cc if you want to use stock heaterboxes...

T

[vwracerdave]

The 1800 "no-machine" engine outlined on aircooled.net would be awesome with stock heater boxes. IMHO 1776 or 1835 is the largest I would build.
90-95 HP would be very easy with all off the shelf parts for a novice builder.
_________________
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

[[email protected]]

[Mikedrevguy]

Any reason not to spend the dollars and get a gas heater?
_________________
74 1303 (RevBug): plan for German Look
76 914 with 2260
79 VW Iltis
69 Bwajaja
"The wise speak because they have something to say; while the foolish speak because they have to say something." Plato

Illigitimi non-Carborundum!!

[gt1953]

Oh the gas heater would be the best option to use. That way you don't choke the engine off.
_________________
Volkswagen: We tune what we drive.
Numbers Matching VW's are getting harder to find. Source out the most Stock vehicle and keep that way. You will be glad you did.

72 type 1
72 Squareback
({59 Euro bug, 62, 63, 67, 68, 69, 73 type ones 68 & 69 type two, 68 Ghia all sold})

[Alstrup]

As I understood it the exersie was NOT to install a gas heater.

That said. I just remembered that we did something else on a 2110 daily driver back in the early 2000´s. We used a 1½" Kymco header with long collector Then we made two small boxes to go around the tubing from cyl 2 & 4 like the ones on a stock muffler, and then routed the air down to the 1½" "performance" heater boxes. That actually worked very well. The heat exhange was just about on the level to equal a stock heater box without the preheat from 2 & 4. That engine pulled about 145 hp and 200ish Nm torque. On really cold days you would still want more heat, but it definitely prolonged the comfortable season quite a bit.
If one wanted to be a little creative that could also be implemented on say a Python 1 5/8" header, And CSP offers SS 1 5/8" heat exchangers to go with it. So today it is not even that difficult. But at the end of the day it may be just as cheap and more efficient just to install that gas heater. So there we are back to square one. But as long as you do not need more than 1½" exhaust, the parts are reasonably priced and accessable. And with a little patience and creativity you can make such small boxes for 2 & 4 yourself, or maybe a friend can help.

T

[[email protected]]

[[email protected]]

SCAT USED to make the best street header around. Their header has the preheaters on the 2 and 4 primaries, like the stock muffler. It makes a significant difference in heat output.

Someone could make a good business making these for headers, FWIW.
_________________
It's just advice, do whatever you want with it!

Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net

"Like" our Facebook page at
http://www.facebook.com/vwpartsaircoolednet
and get a 5% off code for use on one order for VW Parts ON OUR PARTS STORE WEBSITE, vwparts.aircooled.net

[modok]