Will a 16V audi 80 sport cylinder head fit a 1.8 8V?

trogdor · 04-08-10, 10:22 AM

Hi everyone,

I am currently repairing my trusty Audi 80 1.8S 1989, it has an RU engine I think?

Anyway in the future I would like to increase the performance for the engine by replacing the ageing carb that it has for bike carbs. This will mean a new inlet manifold etc and I will probably run the ignition with megajolt or similar.

Anyway the 1.8S 8V head is a non-crossflow design meaning poor flow and that the exhaust is under the inlet making it difficult/impossible to fit bike carbs.

So rather than changing the whole thing can I fit an 16V head from an Audi sport onto my engine?

If it will fit does it effect the compression ratio or worse get unfriendly with the pistons?

How does the timing belt run on these engines? Ie is the water pump part of the routing (like on 5 cylinders) or external like on mine?

If this is possible I would love to hear from someone or if there are any major hurdles I would also like to hear them.

Many Thanks

msh · 04-08-10, 04:44 PM

Again bike carbs... Why they are so popular in west?

Cars have car carbs, bikes have bike carbs and there's no need to swap them

And, after all, it's 21st century now, and carbs are one of technologies we must forgot since 20th century is over

Anyway, idea about coupling 1.8 bottom with 16v head must be bad one - at least 2.0 8v bottom coupled with 16v head results in engine with enough low compression ratio that turbocharger and proper engine management must be used in order to extract some serious power [up to 300 bhp with stock internals]. Dunno about 1.8, but probably the same story. Maybe even lower CR, since 2.0 8v has higher CR because of fuel injection.

trogdor · 04-08-10, 05:42 PM

Well i was under the impression that bike carbs are like using twin 40 webers but on a budget? I know there are issues with bike carbs, but thought they were outweighed by advantages.

So the compression ratio will be quite low? Thats better than too high i guess as i could get the head skimmed to increase the compression ratio back up? Would probally get the head refurbished before fitting it in any case.

Though the idea of fitting a turbo and upgrading to mega squirt is quite tempting!

sam · 04-08-10, 06:16 PM

bike carbs are cheap and dont need looking after nowhere near as much as webers/dellortos etc im all for bike carbs. and its been done many times on that engine. ive experienced a type 85 80 on carbs, possibly a cam too and it was pretty quick, wiped the floor with my b3 80 sport at the time... i should imagine golf manifolds will fit fine and be easier to find

4v6 · 04-08-10, 06:21 PM

Just fit a set of dcoe's at least you can get standard jetting for those, the bike carbs arent going to be easy to get setup at all- as theyre setup for a bike.

David Small · 04-08-10, 07:24 PM

Stick a 2 litre 16V in it - it will be like a new car ! - pick em up dead cheap there's one on pistonheads at the £200 quid for the whole car !

04-08-10, 07:24 PM	#6
David Small David Small - Mr 80k Classic Audi Club Member Join Date: Apr 2008 Location: West Yorkshire Posts: 7,210	Stick a 2 litre 16V in it - it will be like a new car ! - pick em up dead cheap there's one on pistonheads at the £200 quid for the whole car ! __________________ David Small - Member 283 - 1994 Audi C4 A6 2.0 - Tornado Red 1971 NSU 1200C Automatik - Iberian Red 1995 Audi B4 80 2.6SE Automatic - Laser Red

04-08-10, 04:44 PM	#2
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	Again bike carbs... Why they are so popular in west? Cars have car carbs, bikes have bike carbs and there's no need to swap them And, after all, it's 21st century now, and carbs are one of technologies we must forgot since 20th century is over Anyway, idea about coupling 1.8 bottom with 16v head must be bad one - at least 2.0 8v bottom coupled with 16v head results in engine with enough low compression ratio that turbocharger and proper engine management must be used in order to extract some serious power [up to 300 bhp with stock internals]. Dunno about 1.8, but probably the same story. Maybe even lower CR, since 2.0 8v has higher CR because of fuel injection.

04-08-10, 05:42 PM	#3
trogdor Newbie! Join Date: Aug 2010 Posts: 11	Well i was under the impression that bike carbs are like using twin 40 webers but on a budget? I know there are issues with bike carbs, but thought they were outweighed by advantages. So the compression ratio will be quite low? Thats better than too high i guess as i could get the head skimmed to increase the compression ratio back up? Would probally get the head refurbished before fitting it in any case. Though the idea of fitting a turbo and upgrading to mega squirt is quite tempting!

04-08-10, 06:16 PM	#4
sam Grown up member Classic Audi Club Member Join Date: May 2008 Location: North east Posts: 778	bike carbs are cheap and dont need looking after nowhere near as much as webers/dellortos etc im all for bike carbs. and its been done many times on that engine. ive experienced a type 85 80 on carbs, possibly a cam too and it was pretty quick, wiped the floor with my b3 80 sport at the time... i should imagine golf manifolds will fit fine and be easier to find

04-08-10, 06:21 PM	#5
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	Just fit a set of dcoe's at least you can get standard jetting for those, the bike carbs arent going to be easy to get setup at all- as theyre setup for a bike.