2.0 Turbo 16v Conversion

[tyerz 1]

Hi guys iv been told it is possible to bolt a 16v head onto the 8v turbo engine to make a 16v turbo?

 

So was just after a little more info, i have a GTi-6 head and bottom end but can i use standard turbo pistons?

also what managment do i need to use?

 

any information on the conversion would be greatly appreciated

 

many thanks chris

[Daviewonder 533 3 Cars]

You can use a 16v head on an 8v turbo bottom end but the bottom end needs to have the earlier (RGY engine) flat top pistons to allow for valve clearence, the later turbo blocks (RGX engine) had concaved pistons and the sides of these will come into contact with the valves. Some people have had great success using a decompression plate to lower the CR on the 16v engines so this method would also be worth a look.

[jonnyturbo 3]

i thought compression was too low using the 8v turbo pistons? people use s16 with a bit shaved off iirc

[Daviewonder 533 3 Cars]

i thought compression was too low using the 8v turbo pistons? people use s16 with a bit shaved off iirc

 

 

I did a little research a while back, my plan was to use an early turbo block with its flat top pistons with a gti6 head. If I remeber correctly the turbo head combustion chambers are 36cc and the gti6 combustion chambers are around 37.2, you can bring the gti6 chambers down to the same as the turbo ones with a 0.25mm skim so as long as there's no piston to valve contact every thing should be ok?

 

I can't guarantee the above btw

[tyerz 1]

right so let me get this right then, if i get s16 piston they can be used in the turbo block with a GTi-6 head? would i also need to use a GTi-6 crank and rods or standard turbo ones? sorry if im being stupid

Edited July 28, 2010 by tyerz

[Daviewonder 533 3 Cars]

right so let me get this right then, if i get s16 piston they can be used in the turbo block with a GTi-6 head? would i also need to use a GTi-6 crank and rods or standard turbo ones? sorry if im being stupid

 

No. If your turbo block has the earlier flat topped pistons you can use a 16v head on it as the flat topped pistons have more valve clearence.

[jonnyturbo 3]

read this tyerz http://forum.205gtidrivers.com/index.php?showtopic=111646

 

im sure i read somewhere that a guy used an 8v turbo bottom end with s16 crank and pistons and head but iirc he only used the bottom end as he had one anyway and saves drilling in to the sump on the s16/buying one anyway.

Edited July 28, 2010 by jonnyturbo

[Rob Turbo 3]

I've built a 16v turbo engine (yet to get it running though) using an 8v turbo bottom end, I had the later dished pistons so I bought s16 pistons/rods and crank but machined 1mm off the top of the pistons before fitting to lower the CR, I'm using a gti6 head though. Hopefuly get it running sometime this year!

[tyerz 1]

hmmmm just been reading that and iv always been told decompression plates are a pile of s*ite..... might look into one of them as i have a complete GTi-6 engine laying about.......

also have a spare turbo sump in the garage too

Edited July 29, 2010 by tyerz

[Tom Fenton 1,542]

Don't forget that your biggest challenge will be sorting an exhaust manifold. If you have plenty of cash one can be bought from a place in Holland, otherwise you are looking at either making your own, or having one made for you.

[opticaltrigger 52]

hmmmm just been reading that and iv always been told decompression plates are a pile of s*ite..... might look into one of them as i have a complete GTi-6 engine laying about.......

also have a spare turbo sump in the garage too

 

Hi tyerz.I have heard similar tales myself but I have never suffered any problems with them.

Provided that all is flat and stays that way you should'nt see any issues with a plate.Sure it cant be as good as no plate but it's not the most painfull compromise.

 

O.T.

[welshpug 1,661]

how much are the plates to lower compression?

 

if its anywhere near £100 you might as well get the pistons machines to accept the 16 valves and lower the compression anyway.

[opticaltrigger 52]

Yep,Thats very true,I did'nt think of it that way Welshpug.Your quite right.

The pistons is a much better way to go if your gona do it properly.I supose plates are a way to overcome the issue as aposed to solving it I guess.

 

O.T.

[tyerz 1]

can the 8v turbo pistons be machined down enough to allow the 16v valves to clear?

[Daviewonder 533 3 Cars]

I dont see why not but with the earlier turbo engine having a CR of about 8:1 and the later engine having a compression ratio of 8.5:1 adding cutouts for the valves to clear the pistons would lower it even more which is far from ideal.

[jonnyturbo 3]

I've built a 16v turbo engine (yet to get it running though) using an 8v turbo bottom end, I had the later dished pistons so I bought s16 pistons/rods and crank but machined 1mm off the top of the pistons before fitting to lower the CR, I'm using a gti6 head though. Hopefuly get it running sometime this year!

 

 

think your the one i was on about

[tyerz 1]

Right so think the best thing to do would be to skim a little off the top of the GTi-6 pistons and build on that then,

The reason i cant use the 8v turbo block i have is that the first plans for it was to use it as a spare for the engine i have but the bores were knackered so had it rebored to .6 oversize and got some mahle pistons to suit.

Which is all good but cant get t16 pistons in oversize without getting wossner or such like same with GTi-6 pistons so might sell the rebored block and pistons.....

[jonnyturbo 3]

i heard something like s16 pistons are stronger then gti6? which is why there used

[Rob Turbo 3]

I don't know about s16 being stronger than gti6, but the s16 have floating gudgeon pins so it's easy to seperate the piston from the rod for machining, where as the gti6 is a press fit and you can damage the pistons when removing the pin if you're not careful.

[James_m 0]

I can't help but think an s16 would be a better base for a turbo than a gti6. It also has a lower static cr in the first place.

 

It depends on your aims, but personally id be tempted to leave it stock internally and boost it, VAG is running 10:1+ on some of its newer turbo engines.

[welshpug 1,661]

You don't need to remove the piston from the rod to machine them.

[Rob Turbo 3]

You don't need to remove the piston from the rod to machine them.

 

I did, it wouldn't fit in the lathe otherwise!

[welshpug 1,661]

Martin didn't, and Colin doesn't either!

 

But then they don't use a lathe to sort them I don't think.

Edited July 30, 2010 by welshpug

[Guest levis]

Hi, may I drop my question here...

 

I am building a Turbo engine.

 

Right now it is going to be a XU9J4 + head from XU10J4TE + cams from XUJ94 + Crank from XUD9TE + pistons from XU10J4TE + Turbo GT28RS

 

My goal is 300-340 hp.

 

QUESTION:

 

Which rods to use: XU10 = 86mm, XU9 = 88mm

 

Where I can buy a good liners and rings (I don't know the proper name).

 

any suggestions for me in building this engine ?

 

Thanks :-)