Increasing displacement ( increasing bore size)

[emery1990]

do you think this is worth while getting if you want to max out performance to your car.

how much extra torque are we looking with a 1.9linstead of a 1.8l? ive heard gains of around 20 whp and 35wtorque for an increase to 2.0l

our people aware of any stroker kits for an audi, only seem to find them for the jap cars ?

or anyone got it done?

 

[Dani_B19]

Ive breifly had a look at a fwe stroker kits but got a bit too heavy for me, well for now it did. The one thing that puts me off storker kits (i could be wrong so please correct me) but dont they limit the top end performance and also shorten engine life?

 

[emery1990]

i couldnt say, but yer they seem quite complicated, was wandering just about boring my engine, then obv get larger 1.9 pistons. or can you put the top of a 1.9 engine onto the top of my engine ?

 

[<tuffty/>]

I am planning to stroke my engine as the next stage of my tuning...

You are obviously aware of the sticky outlining the whys and wherefores, try here for starters...

http://www.intengineering.com/Stroker-Kits/18t-20v-20L-Stroker-Kit-p5995930-1-2.html

2ltr will give more base HP, a few extra ftlbs of torque and better spool on the turbo.

Its a popular mod in the states but there are a few of the seat cupra net boys that have done the conversion.

<tuffty/>

 

[emery1990]

i see. is this the kit your planning on getting then, or are you going to get yours bored wider? im just finding out about things at the moment though,cant till next year hopefully as of the insurance, but doesnt hurt to know.

 

[Dani_B19]

But what are the downfalls to fitting a stroker kit?

 

[<tuffty/>]

i see. is this the kit your planning on getting then, or are you going to get yours bored wider? im just finding out about things at the moment though,cant till next year hopefully as of the insurance, but doesnt hurt to know.

As I am going to have to take the engine apart, I would look at going 82mm or maybe 82.5mm over bore as it would kinda make sense to refurb the whole engine whilst its in bits... 83mm is a little close to the water jacket for my liking and while there are no major horror stories, I would like to build an engine that will last as long as an out of the box one if poss... oh... and 83mm needs a different head gasket...

But what are the downfalls to fitting a stroker kit?

Expense at a guess

<tuffty/>

 

[emery1990]

i really needs to get friendly with a good mechanic or something to help me with this car !

yer i guess your right..you rekon about a 2k job then ?

 

[Dani_B19]

Is that it though just cost! I thought it affected top end performance! If it doesnt i cant see any downsides to it only up's really.

 

[<tuffty/>]

Difficult to say tbh... really depends on what you plan to do with the rest of the car...

Bit pointless building a 2ltr if you are gonna run it off a K04... thats why I am doing mine as a BT first as you get a better return for your cash...

I didn't want to build an all singing all dancing 2ltr if I couldn't get it to make power beyond 7.5k else thats a grand of head work down the pan. I wanted to establish a base line and see if going 2ltr was actually going to give me some benefit either power wise or reliability wise.

I would imagine to make a decent 2ltr, you would need the stroker kit, replacement oil pump, gaskets, large port or ported small port head, valves and springs. That lot alone would cost over 2k before labour.

To even make any use of it a stage 2 or more likely a stage 3 remap would be needed and thats a lot of money just to get no more than a remapped 8P S3 power if you are still using a K04....

Either factor a massive budget and get it stroked and big turbo'd at once or go BT first then stroke later if you feel you really need more out of it.

Bare in mind that you will prolly need at least a GT3071 to make full use of a 2lt and with the right head rebuild, you can up the rev limit and go for a larger hotside...

Thats what I am doing anyhoo...

<tuffty/>

 

[<tuffty/>]

Is that it though just cost! I thought it affected top end performance! If it doesnt i cant see any downsides to it only up's really.

Depends on what turbo you are running... as mentioned above, not really worth going to all that expense for a K04...

You really need to go BT of some kind...

<tuffty/>

 

[emery1990]

i see what your saying, so doesnt this seem to be a move towards having a racing specced car then ? as having power after 7.5k on road conditions isnt really worth having imo. I didnt relise how much work would have to into having a stroker fitted! Its all early days for me though, id like to go bt in the future, cant decide whether to get the a3 to massive power or just buying a car which has that power already. the a3 would be more satisfying though!

 

[Dani_B19]

Nar cant justify going BT on the 8l s3, rather do the suspension, barkes etc then go down the ko4 hybrid with the jbs manifold and dahlback intake and uprated rods and valves, only want around 350 bhp and around 350-370 lb/ft, wether i make it or nots another thing

 

[<tuffty/>]

You don't need to build something 'race spec' with a stroker kit but its a lot of money for what little power increase you get without a bigger turbo.

Just fitting the stroker kit and running it on a std K04 (or hybrid) wouldn't see you much return for your cash. A big turbo would prob be better use of your cash and give you more power for your money than a stroker on its own.

<tuffty/>

 

[emery1990]

youd need more than k04 hybrid to get ONLY 350bhp ..only double the power of my car lol.

what car would you get to got bt on then ?

yer true. ill look into the bt route before i thinks about a stroker then.

 

[<tuffty/>]

Nar cant justify going BT on the 8l s3, rather do the suspension, barkes etc then go down the ko4 hybrid with the jbs manifold and dahlback intake and uprated rods and valves, only want around 350 bhp and around 350-370 lb/ft, wether i make it or nots another thing

That was my original route, but bare in mind a hybrid K04 and JBS mani will set you back just over a grand. A GT2871R on a PAG Parts mani will be a little more than that and you are already doing the rods. Valve gear is a lot of expense to throw at a K04 I reckon... valve gear is worth doing if you can up the rev limit to take advantage of a bigger turbos increased flow producing more power up to and beyond the factory rev limit. You would get more reliability of course.

You would prolly still need at least stage 2 mapping and defo a FMIC on a K04. 350bhp is unachievable on a K04, hybrid or otherwise as far as I know... GT2871R is prob what you want for that (GT2860RS too)

http://pagparts.com/product_info.php?cPath=1_8_27&products_id=44
http://pagparts.com/product_info.php?cPath=1_8_27&products_id=45

http://pagparts.com/product_info.php?cPath=154&products_id=582

Might have to have a word with them though as the comp housing will need to be smaller using that mani... my GT3071 has a smaller comp housing machined to take a GT30 comp wheel...

<tuffty/>

 

[Dani_B19]

Or yeah a FMIC is a must, i getting the set up you have paul.
I dont know, jbs quote with their hybrid and mani that between 320-340bhp and 340-360lb/ft is acheivable and thats without a aftermarket intake maniflold, the dahlbacks are meant to give a gain of 10-15bhp on engines over 300bhp but lik we all know figures need tobe taken with a pinch of salt.

 

[<tuffty/>]

To get 340 + of torque, they must be running bonkers boost levels... Would rather run bigger turbo on less boost to get that... More reliable and believable

<tuffty/>

 

[Dani_B19]

Haha i know what your saying mate, think it peaks at 2 bar then holds at either 1.4 or 1.6, cant remeber.
I know BT would be more realistic figures but its never appealed to me for the s3, rather have an evo or s4 for that.
My plan is todo the suspension and brakes and put the s3 on a diet to lose 100kg or so and i think coupled to hybrid i think itll compliment the s3 and make it a very nice all round car to give a few cars a good run.
Thats my 2pence worth lol.

 

[Effect]

what is stopping someone from bi-turbo'ing or supercharging + tubo'ing an 8L 1.8T engine ?

I like the sound of going for more power etc (not that i ever will) but it comes at the expense of lag with bigger turbos.

 

[IIIadidasboy]

i see what your saying, so doesnt this seem to be a move towards having a racing specced car then ? as having power after 7.5k on road conditions isnt really worth having imo. I didnt relise how much work would have to into having a stroker fitted! Its all early days for me though, id like to go bt in the future, cant decide whether to get the a3 to massive power or just buying a car which has that power already. the a3 would be more satisfying though!

As tuffty said, if you've done the right combo of mods to allow you to up the rev limiter, then to have power still coming on strong above 7.5k is worth it in my opinion - you'd definitely see an improvement in 1st through to 3rd/4th - although admitedly you'd not see it in 5th/6th (at least on public roads )

I've been thinking about this for next year as well, but like you it's still early days and so I just haven't looked in to it enough as yet - but for me, I think the power delivery in 1st through to 2nd is what lets these cars down and this seems to be the perfect answer - I always find that in 1st/2nd you're always waiting for the turbo to kick in and then when it does it's all over to quickly - so having a car that revs higher and has more base power says win win to me.

And yeah, hopefully more satisfying!!



Boost spiking to get good published dyno results isn't good in my opinion, I'd rather have a set-up that "boasts" less power but is reliable and still driveable like a "daily driver" - max power figures aren't everything, how it drives is more important to me.

 

[<tuffty/>]

The problem with fitting a bigger turbo is of course increased lag. The K04 was only really designed to give you a little push at low RPM which of course makes it feel quick under 'normal' road conditions which starts the power band quite low down the rev range but tails off before the redline.

With a bigger turbo, yes you get more power and yes you can get power all the way to the redline but due to later spooling (lag), your power band narrows and if you change gear like you do on a K04 then you could drop out of that power band and have to wait for the turbo to spool up before the power kicks in again... if the turbo can produce power up to and beyond the redline then increasing the rev limit will give you your wider power band back. You say you don't need a higher redline on a car but look at the RX8... that redlines somewhere around 9k.

You may actually get a proper 0-60 time on a 6 speed box with the rev limit increased ;P

<tuffty/>

 

[IIIadidasboy]

........You may actually get a proper 0-60 time on a 6 speed box with the rev limit increased ;P

<tuffty/>

That's precisely what I was thinking

Plus, if you've increased the base power of the engine, then hopefully the lag you'll see on a bigger turbo wont be so noticeable.