Introduction and heat riser discussion

[The13bats]

I do not own a buggy at the moment but have putzed with countless vw based kits, buggies customs etc over the last 40 + years, and right now my toy is a trike so im hoping you buggy guys will allow me to tag along for open minded tech ideas, i was researching the subject of heat risers and found a thread here and joined because of the more open minded out of box thinking than other vw forums i find that are more purist based,

I was set back, I found on the net one scathing rant that not only insulted, belittled and disparaged anyone who isnt basically running 100% stock but makes the ludicrous suggestion a vw wont run without heat risers, really? dont tell mine they run well with no risers ( im in central florida )

Heres the thread here i enjoyed and didnt want to highjack

https://www.manxclub.com/forum/viewtopi ... =81&t=3906

In my case my intake right below the carb does get cold it does sweat but only iced up once that was about 2am 40s out coming back from daytona bike week, it was horribly cold, we stopped to get a soft drink and i took a look at the engine because it wasnt wanting to idle well but was running down the road fine, i was surprized to see frost under the carb mount a few inches, it was melting quickly and like i said did effect running so i didnt forget it.

Im OCD and the heat riser idea hit me, my trikes intake has none and even if it did heat riser tubes do not work as designed if we are running buggy exhaust, heat risers will only work correctly if the full stock set up is there,
if heat risers are ran with aftermarket exhaust the heating effects will still happen just not nearly as much as stock.

im not wanting to buy a new intake to get heat risers but on the otherhand i ride mostly at night and the intake does get cold and sweats, ocd asks would i run better better with warmer intake? i saw a link in the thread from here i posted above a guy was trying to heat his intake with cycle grip warmers, it didnt update how that worked out,

My mind engaged, my stock intake has a large vacuum fitting blocked off, i thought i could tap that tube or add a bung and screw in a atv carb heater, it would likely heat up my intake not as hot as stock risers in stock exhaust set up but likely warm enough not to sweat,

So, my question is would it be worth the efforts, if you run with no risers please give me details, also it was mentioned carb spacing effect intake temp please tell me more about that,

many thanks,
cheers
b

[lastmanx]

I run with no heat risers successfully for 30 years. the spacing above the carb refers to the air fuel fog standoff mixing inherent in the stock oilbath filter. see the Muir book article. think of a velocity stack. Heat risers allow you to operate in cold weather, that's it. My buggy cant operate in temperatures below 55 degrees. In cool spring and cool fall temps my buggy runs fuel rich, requiring a light gas pedal response. Having a carb ice up at speed is dangerous. Running with heat risers all year wont greatly affect the engine. If your exhaust has no connection for risers; it is easier to get exhaust that does. My 4 pipe megaphone exhaust has no connection, so the manifold risers are sawed off,for a cleaner look. I benefit with cold induction, and very load exhaust tone.

[The13bats]

Thank lastmanx, i very likely am letting my ocd get the best of me on this, ive owned and messed with a lot of vw vehicles and just never paid much attention to stock heat risers actually i dont recall messing with anything that didnt have aftermarket exhaust, in the 80s i used a sterling kit car as daily transportation no heat risers and it ran fine,

the trike i have now its not likely ill be out on it in weather colder than mid 70s,

I run a generic aftermarket air cleaner not sure if i have room to raise it but would it be better to have it off the side on a ghia style elbow?

many thanks
b

[manxvair]

Do you "need" heat risers? Short answer is no. Will they help your buggy run better? Maybe. As it was once explained to me, If you are running a single carb, the manifold runners are much longer than the ones for dual carbs. As such, on the longer runs for the single carb, the fuel that is atomized and going to the combustion chamber tends to re-condense into little droplets that are harder to ignite than properly atomized fuel. The heat from the heat riser transfers the heat to the atomized fuel and helps keep it atomized making it easier to burn. This is an added benefit over just keeping the carb from icing up.
This was in the other thread, I removed the center mount carb on my corvair for this very reason, it would run but had a just off idle flat spot, I went back to stock carbs and it runs better and I live in So-Cal. the heat definitely helps keeping the fuel atomized.

[The13bats]

Thanks mike, i saw the part you cut and pasted i was hung on the word "maybe" when stated, "will it run better" i also saw someone post somewhere ambient temp has no bearing, hogwash.
its odd with my 454 vette carb sitting on engine we want cooler intake but with vw we want warmer,


gm just didnt mess with it with vairs they ran duals except the spyder and the turbo kept things warm there, useless trivia, i was almost born in the back seat of a then new in 64 vair during a hurricane.

In a case like me im not really wanting dual carbs nor will they clear my exhaust, im pretty friendly with the pict 34 3,
i will not consider all stock exhaust and for vw heat risers to work as designed it all has to be there, sure, many aftermarket vw exhaust has the mounts for the riser tubes but this wont be like stock it will be a ping pong effect not flow thru, per say, it will get warm at the intake but i would question how much plus now you have a new source of issues, and ugly hot tubes in the way,

i have seen guys suggest using 12v cycle grip heaters but i have serious doubts it will heat enough to help, and mounting will be tricky or look hack jobbed.

im looking into atv carb heaters and also interested in air cleaners and whats the best in the no riser situations,

[manxvair]

I actually have a Meyers Manx sidewinder setup on the shelf for a future build with the heat risers.

http://meyersmanx.com/buggy-parts/sidew ... haust.html

[The13bats]

its good looking exhaust but like i was saying its not going to heat the same as stock, with stock the exhaust is flowing through the heat risers, but on exhaust like that and what i use ( nut mines not hooked up ) the pulse will be back and forth the result will be less heat to the intake not sure how much less because i could see stock being too much on a 90s day out trashing or stuck in traffic.

[lastmanx]

the gia elbow would be better,if its not running good. short aftermarket filters tend to run fuel rich, but the carb can be adjusted to compensate. understand vw intended their vehicles to be idiot proof and not messed with. dunebuggys are all custom; very much messed with since vw never made or approved of them. for example my buggy is modified to run in very soft sand under very dusty salty conditions on the beach, the modifications allow it to run on the street as well. it is no longer stock oem.

[YellowSafari]

What Carb\s are you running, I was told by a VW engine builder that the cast alum center carb mani for IDF's needs the heat riser to help eliminate the bog at take off. I don't use the heat riser I still have small hesitation on take off esp at high altitude. I found distributor advance curve helped with bog.

[The13bats]

im using a pict 34 3, my old first trike had a screaming 1835 dual webers etc but the trike i have now is a kiss idea,
the intake is stock dont know what year but its got a big vaccum port out the left side, plugged but im goung to cut it off and fill the hole, heat riser were gone when i got it,
after a bit of thinking i ordered a 20" piece of heated silicone belt its to keep the inlet hot on bio diesels,
im gonna wrap it around the intake under the carb and run it out where the intake Ts off,
i will update if it works out,

i have it tuned very well i do notice at take off when the intake is cold and sweating but its not at all bad, i just wamt to see if the heater helps

[YellowSafari]

yeah a Pict 34-3 intake doesn't have the giant throat under the throttle plate. Yes your bio diesel heater may help on those cold days. I was thinking it doesn't need to be exhaust to warm intake. I suggest a heater on lamp in instrument display, or a hot in run only, to keep from killing battery if left on with trike off.

[The13bats]

yellow,

once coming back from daytona on a bitter cold night i had frost on the intake it still ran, it got me home it lacked a little power and didnt like to idle but ran, so much for those saying it wont,
that was rare for me to be out on it that cold out.

what bugs my ocd is it can be 90s out and still get cold and sweat right under the carb
The heat belt will help and wont overkill like i feel stock exhaust fed heat risers can, too hot isnt good either,

my wiring will be a relay for the belt, for testing i will use a switch i want to see if i can tell any difference in running
then if i like it i will just switch the relay with the hot going to coil which is only on when running,

[lastmanx]

hi bat. today my wife declined a ride in my buggy; because she knows I have no heat riser, and the buggy will run s*itty. It will run; due to its perfect tune and my gentle throttle response. Just so you know; the factory heatriser system is weak. it is intended to heat to room temperature, or only as hot as a sunny day. It rapidly rusts from the inside and becomes blocked. Your carb is supposed to sweat, and will even with heat. It wont freeze up, which is the reason the device is there. sorry if you already knew that. My tips for cold driving don't apply to trikes. For stock pedals (no roller pedal) you use the top of the gas pedal, lift your foot to it, that way if you push too hard you don't actually put too much fuel to carb causing a stall. If you were at the bottom of pedal you would flood carb. Teach yourself to hold the brake with the ball of your foot, while you tap or press the gas pedal with your four outer toes, without taking the foot off the brake. An out of tune buggy may not run good at all. My wife says its not much fun sputtering, stalling, and bucking along. today my wife declined a ride in my buggy.

[Chicago Joe]

LastManx: Today you are a lucky man. Enjoy your solo ride.

[lastmanx]

joe, she was right, the buggy ran cold. it will be parked for the year on October 31.