VW tuning info?

[slater]

I'm looking for some info on tuning Aircooled VW motors. My fiat engine is basicaly half a VW flat 4 so i think there will be alot of cross overs.

Anyone know any good books or maybe websites?

[Panda Matt]

I doubt I'll manage to be first to reply, but...

How to Hotrod Volkswagen Engines is the 1st point of call for a traditional look at vw engines.

Other than that, and for the more exotic stuff, you need to read some of the stuff on Volkszone Readers Rides or ask in the VZi Mech Tech I'd say

[VW]

i know the cheapest way to get power out of a vw motor is to turbo it.
Other than that, the usual route is larger barrels and pistons and stroker crank then cams and headwork etc.

I know about tuning them, but its hard to give you any advise, VW bits wont fit your motor and tuning engines is always the same principals of increased capacity and getting as much fuel/air mix in as pos, which you already know.

Is there anything specific you want to know? Are you looking for parst that cross over, or ideas?

[hudsonhenry]

Slater

VW pistons and barrels can be made to fit. Takes the engine out to 800cc, the waek link however is the crank, there is a polish site that shows what to do, Have a look at www.126fan.pl/ in the menu look for:

Dzia? Techniczny
- Maluch 800 ccm

Lots of other mad conversions there as well like a wheelie pulling vw turbo powered 126

[Keefy]

for books check aircooled interchange manual and turbomania for turbo stuff
like vw said though, it will all be vw specific so pretty much none will be interchangable
ive only flicked through the 'how to hod rod....' book and i thought it looked sh!te personally

[slater]

I'm just looking for ideas relly. I need to find out what mods they do to make them do 10sec quaters with out luching the engine! Mainly info on how they strengthen the bottom end, Air cooled cooling systems, basicly anything that they have which you don't get on a normal inline 4 watercooled engine or a single cylinder bike enigne cous thats all ive had experiance with. I know vw specific books are going to have alot of VW specific stuff in them but I don't mind that so long as I can learn from it. I don't relly want a vw parts interchange manual tho. That turbomaina book loooks promising.

I'm planning to fit some 1600 pistons but I was going to make my own barrels, partly so its neater and lighter and partly so I can put more cooling area on them (i assume the Vw 1600 barrels are iron too?) Your right the crank is the weak link but if I can keep the power low down in the rpm range by using a mild cam I think it will be ok. It will definatly be turbo'd as I can see any other way of making it produce sensible power. I'm looking to run a dry sump system to get rid of the stupid oil pump system that have as standard and it should allow me to fit a oil cooler and proper filter aswell. I was wondering if the engine driven cooling fan could be replaced with an electric one to save some power but I'm not sure yet. its not just going to be a case of porting the head and chucking a cam in it.

[Keefy]

although its called an interchange manual its not about parts interchangeability - its all about building top motors, the parts available, various tips etc. it is the vw performance engine builders bible.

cooling is all about making sure the oil can do its cooling job, and that hot air can escape. Bear in mind most dubs running 10's wont have cooling.
to get them running fast isnt too hard, the vw units are pretty hardcore and theres a world of uprated parts for them. You then gotta consider the box tho, its the weak link in a vw and ive got no idea how the 126 one would stack up against some decent horsepower

I'm guessing you just want to learn about dubs, and then work out how/if that can be applied to the fiat yourself (which I'm guessing you are more than capable of doing) - in which case definitely get a copy of the Aircooled VW Engine interchange manual.

Hot VW's did an issue on building performance vw's. If you can get a copy of that, that might also be useful to you.

[garethj]

Revs can destroy a crank but bear in mind that any higher forces like more compression pressure will make it want to bend as well.

How about a motorbike crankshaft? There are a few 600cc - 800cc 2 cylinder bikes and they generally rev quite high too (compared to car engines). My old Yamaha XTZ750 is a 2 cylinder, and a similar engine was used on the TDM 850 and 900. It's water cooled but that doesn't matter for crankshafts.

The main problem with modified aircooled engines is heat, extra oil coolers can help but the main source of heat is the cylinder head so be careful to get rid of the heat from here and not just bang on the biggest oil cooler you can find.

I'm no bike expert, but the ER-5 is a 2 cylinder aircooled engine and they're cheap and plentiful. Maybe a good place to start for crank, cylinders, heads and carbs?

[slater]

It just the nature of the inline twin thats the problem, i keep thinking i should make a steel crank but its alot of work to make one from billet and alot of money on the line if you get it wrong.

The gearbox is another issue entirely. 1st gear is awful and breaks on stock engines so i might just make it a 3 speed or something

[garethj]

slater said:

It just the nature of the inline twin thats the problem, I keep thinking I should make a steel crank but its alot of work to make one from billet and alot of money on the line if you get it wrong.

That's why it may be better to start from a motorbike crank that you can get machined, or machine the Fiat crankcase to accept the motorbike bearings etc

[hudsonhenry]

I thought about the TDM crank as well, might be worth a look, I also looked at the BMW boxer engines.

The other thing that might be worth looking at if you can find one is the engine from one of those blue disabled three wheelers, they have the basicly same engine as the Steyr Puch 650 TR (the fastest version by far of the 500 back in the day) They go great with a couple of big Bing carbs.

Or what about cutting a 4 cylinder VW engine down to make a boxer twin? There is a guy in New Zeland who cut a Tipo engine in half to make a parallel twin!

Citroen Visa aircooled twin also been fitted to a 500

The cranks on the 126 engine are hollow and don't take too much abuse, I've seen plenty of snapped ones.

[hudsonhenry]

Not sure if I've put this up here before but:




I have some more pics I took at Santa Pod if you are interested

[trg1984]

speak to adaptor man, he knows how to tune VWs, its quite straight forward, just slap a volvo engine in it and giggle ur tattys off