View Full Version : cc increase on 20v... anyone done this?
Hello all,
Was thinking about cc increase on my 20v... I beleive you can get oversize JE pistons which can take you upto 1900cc (Costs less than std 1800) and are uprated pistons.
I know to achieve 2.0 you need to replace the crank, con-rods etc, but that sounds costly... was wondering if anyone had done any mods/engine re-builds?
Cheers,
Leon
Bill has done this on his Golf, its now a 1.9.
The thing to remember with increasing the engine size is that increases power proportionally to the size increase... so an increase from 1.8 to 1.9 is only a 5% increase in capacity and only has the potential to increase your power by 5%, which isn't exactly earth shattering.
Ben
Larger pistons will of course require your engine block to be re-bored. So it's a complete strip down and rebuild job. The other way to increase capacity is to retain the standard bore & pistons (maybe machined for lower comp ratio?) and use a longer throw crack. Both are costly.. In theory you can even do both to get even more capacity.
I don't know which route Bill took however.
ibizacupra
29-02-2004, 12:53
Golfy runs 1.9ltr now on JE pistons and lower CR... (I think it is 8.4:1, could be wrong)
Stock crank, Pauter rods, so same stroke as normal.
The extra cc is not proportional to the gains however. Its more. :)
Deshrouding the valves is the most significant result from the extra bore diameter. It real terms the new motor, running the same spec turbo as previously (pre dropped valved dead engine), now produces more torque, has better lower off boost response and pulls 391bhp & 350lbft from only 1.35bar boost on a stock SMIC.
It used to run this power from 1.5bar boost, SMIC, Chargecooler.
JE pistons to this spec are in stock @ Jabbasport.
It is a complete strip down and rebuild job and not going to be cheap. If bothering to do this, then bung in some steel rods too with ARP fasteners. I have a couple of sets in stock for ickle Ibiza rebuild - one day.
regards
bill
Originally posted by ibizacupra
Golfy runs 1.9ltr now on JE pistons and lower CR... (I think it is 8.4:1, could be wrong)
Stock crank, Pauter rods, so same stroke as normal.
The extra cc is not proportional to the gains however. Its more. :)
Deshrouding the valves is the most significant result from the extra bore diameter. It real terms the new motor, running the same spec turbo as previously (pre dropped valved dead engine), now produces more torque, has better lower off boost response and pulls 391bhp & 350lbft from only 1.35bar boost on a stock SMIC.
It used to run this power from 1.5bar boost, SMIC, Chargecooler.
JE pistons to this spec are in stock @ Jabbasport.
It is a complete strip down and rebuild job and not going to be cheap. If bothering to do this, then bung in some steel rods too with ARP fasteners. I have a couple of sets in stock for ickle Ibiza rebuild - one day.
regards
bill
How expensive is expensive? :D
Ben
Originally posted by bill
Golfy runs 1.9ltr now on JE pistons and lower CR... (I think it is 8.4:1, could be wrong)
Stock crank, Pauter rods, so same stroke as normal.
The extra cc is not proportional to the gains however. Its more.
Deshrouding the valves is the most significant result from the extra bore diameter. It real terms the new motor, running the same spec turbo as previously (pre dropped valved dead engine), now produces more torque, has better lower off boost response and pulls 391bhp & 350lbft from only 1.35bar boost on a stock SMIC.
It used to run this power from 1.5bar boost, SMIC, Chargecooler.
JE pistons to this spec are in stock @ Jabbasport.
It is a complete strip down and rebuild job and not going to be cheap. If bothering to do this, then bung in some steel rods too with ARP fasteners. I have a couple of sets in stock for ickle Ibiza rebuild - one day.
regards
bill
Hi Bill,
Thanks for the reply. I popped my motor hence me needing to do a re-build. Was thinking seeing as I have it open, I may as well go the full hog. Sounds like what you have had is what I will.
Had a couple of questions...
Regarding the Conrods... where, what, how much? Are they available for a 2l version?? IE: If I was going to replace the rods I may as well get 2l rods and get a new crank?
Second question is what compression do the JE pistons give? Does it keep it at 9:1 or does it drop? The drop you had - was that due to the pistons?
Finally, what is Deshrouding the valves??
Cheers,
Leon
Originally posted by BenS1
How expensive is expensive? :D
Ben
My guess... given I am starting to do the maths... complete engine re-build with labour and parts, probably 2.5-3.5K? Not much point though unless you have distroyed your motor like yours truely or if you are running an IHI/Equiv.
ibizacupra
01-03-2004, 12:48
Originally posted by ZeroK66
Hi Bill,
Thanks for the reply. I popped my motor hence me needing to do a re-build. Was thinking seeing as I have it open, I may as well go the full hog. Sounds like what you have had is what I will.
Had a couple of questions...
Regarding the Conrods... where, what, how much? Are they available for a 2l version?? IE: If I was going to replace the rods I may as well get 2l rods and get a new crank?
Second question is what compression do the JE pistons give? Does it keep it at 9:1 or does it drop? The drop you had - was that due to the pistons?
Finally, what is Deshrouding the valves??
Cheers,
Leon
The rods are stock length. Larger bore and lower CR design JE pistons. 2ltr is'nt worth it IMHO.
Get the motor closer to square bore/stroke and it suit the IHI power delivery/rpms. Thats just my motor mind you.
CR is low 8.4:1 from memory. Was 9:1 from S3 pistons.
Elton @ Jabba spec'd the thing up.
Deshrouding the valves, there are so many of them, is done by the larger bore exposing the edges of the valve to bore side, and airflow is increased. 3 inlet makes for a very filled combustion chamber in the head. Larger bore exposes more edge.
regards
bill
Excellent, well I hope that I acheive the same CR as you have. The lower CR would explain the greater power output at the lesser boost level - I hope that means less stress on the motor - given the uprated pistons, this would work out nicely.
The rods - how much are they? I agree with the idea of getting the square bore/stroke.
The original S3 pistons do give 9:1.
ibizacupra
01-03-2004, 16:48
Originally posted by ZeroK66
The rods - how much are they? I agree with the idea of getting the square bore/stroke.
The rods I have are Forged 4340 Steel Rods & come with ARP fasteners. Eurospec Sport items. pukka :)
Supplied as a balanced set.
Price is £495 set inc vat plus P&P
4 Cyl 220mm Block
length - 144mm
weight - 600gr
wrist pin - 20mm
regards
bill
Originally posted by ibizacupra
The rods I have are Forged 4340 Steel Rods & come with ARP fasteners. Eurospec Sport items. pukka :)
Supplied as a balanced set.
Price is £495 set inc vat plus P&P
4 Cyl 220mm Block
length - 144mm
weight - 600gr
wrist pin - 20mm
regards
bill
How much do the standard ones weigh?
Ben
ibizacupra
01-03-2004, 17:17
Originally posted by BenS1
How much do the standard ones weigh?
Ben
you know what? I don't know..
These are pretty heavy duty ones which look to be similar to OE in weight...
Not got any weights for stock ones tho. (yet)
Bill
You running an IHI on that motor by the way?
Rather pricey indeed, didnt realise they were that much! What are they rated to torque wise?
ibizacupra
01-03-2004, 18:31
Originally posted by ZeroK66
You running an IHI on that motor by the way?
Rather pricey indeed, didnt realise they were that much! What are they rated to torque wise?
Yea IHI on Ibiza, and bigger IHI on MKIV Golf
You could always pay Arrow £150 per rod.. :eek:
Don't know a torque figure... They would spec them at tensile strengths anyhow I think.
Eurospec build their potent 1.8T's with them, which is good enough for me. H-Beam section.
Ibiza sport man
01-03-2004, 20:12
Stock rod weighs 595g
Bernard
ibizacupra
01-03-2004, 21:30
Originally posted by Ibiza sport man
Stock rod weighs 595g
Bernard
Thanks Bernard..
pretty similar then. :)
max_torque
02-03-2004, 08:29
Arrow rod with 144mm centres and 21mm pin (my Renaults engine size) weigh 535g, so thats where the extra cash goes then!
(significant saving in inertia when you consider that for a 1.8t at 7000rpm peak piston accel is 3400g, and hence that saving of 60 grams is actually something like 204kg peak on your big end bearings!
(actually it depends where the rods C of G is)
They also have a peak cylinder pressure limit of 200bar! (the head is gonna be ripped off the top of the block way before the rod fails in compression!
As always, speed costs money, how fast can you afford to go:p
Ibiza sport man
02-03-2004, 11:00
I agree that lighter usually equals better but part of the rod mass reciprocates. If you reduce the rod weight wouldn't it cause more vibration due to it changing the balance factor, ie the crank counterweights would then be too heavy ?
Bernard
Originally posted by Ibiza sport man
I agree that lighter usually equals better but part of the rod mass reciprocates. If you reduce the rod weight wouldn't it cause more vibration due to it changing the balance factor, ie the crank counterweights would then be too heavy ?
Bernard
I thought exactly that about the counterweights not being matched anymore. I'm sure I read somewhere about imbalance causing massive increase in loads?
Ben
max_torque
02-03-2004, 12:01
Not a problem on an even firing (every 180 deg) 4 cylinder, because for every rod / piston going upwards, there's one going downwards. but you do get a 2nd order out of balance force coming from the mass of the rod acting around it's C of G. (hence some 4cyls with balncer shafts to counter act this)
In an ideal world you would want the rod C of G to be concentric with the big end centre, hence all 4 rods would balance each other out. VW tryed this with the 1.6 16v (120bhp) by fitting titanium rods with steel caps that had a large mass on them, effectively shifting the rods C of G downwards. It worked, well up until the point they actually tryed to get a durability test, where the titaniums fatigue life caused the rods to split longitudunaly down there centres!
As piston accel is basically the square of engine speed, the more you rev you engine, the more important minimising reciprication weight becomes.
max_torque
02-03-2004, 12:03
Should add a note that some cranks are balanced with a proportion of the rod weight attached, this giving a sort of "intermediate" balance between 1st and 2nd order forces. IF this is the case, then a reduced rod mass (especially as most weight savings from "trick" rods are around the big end where there is usually the most metal to remove)
edited to add........
could unbalance the crankshaft!:D
Ibiza sport man
02-03-2004, 12:22
I see what your're saying about the forces balancing each other out on 4 cyl cranks. I thought that on the Rover K series it was found that the balance weights of the 1.8 engine were not heavy enough to balance out the rods + pistons and that huge loads were being put on the main bearings and crankcase because of this ? Surely just fitting lighter rods in the VW/Audi/Seat engines without correcting the balance factor would produce the same problem ?
Bear in mind I know little about the subject :-)
Bernard
So, in plain english, do you think its a bad idea replace the stadard rods/pistons with ones of a different weight on a high revving tuned 1.8T? I guess the same question goes for machining the standard pistons to reduce the compression ratio?
Cheers
Ben
hopkinsgm
02-03-2004, 12:24
Originally posted by max_torque
Should add a note that some cranks are balanced with a proportion of the rod weight attached, this giving a sort of "intermediate" balance between 1st and 2nd order forces. IF this is the case, then a reduced rod mass (especially as most weight savings from "trick" rods are around the big end where there is usually the most metal to remove)
Then a reduced rod mass...? C'mon, the suspense is killing me!
Surely the people who design these things - Pistons & Rods - take these things into consideration when releasing products? If they afected the motors/stressed them they would not release "up-rated" products as they would not sell???
max_torque
02-03-2004, 19:48
Basically, if anyone is thinking of serious changes to reciprocating components which are likely to add up to over £1000 (rods @ 150 each, pistons @ 170 each etc), then i recommend you have the entire assembly dynamically balanced by a reputable engine builder, to whom you should supply all the reciprocating / rotating bits, inc front pulley / flywheel / rods / pistons / crank / bearings etc etc.
This way you know its right!
As for the K series balance issue, i believe it's because the compact low crankcase and bore spacing dimensions do not actually allow the crank counter weights (fully balanced crank not half balanced) to be large enough to perfectly balance the crank. Rover get away with it at just about 7000rpm, but VHPD's etc at 9000 rpm see torsonal crank failures. There is one K series crank guru, who adds "heavy metal" inserts into the counter balances to properly sort this out. BUT at something like £800 a go, you are 2/3 of the way to just getting a forged steel crank anyway.
Oct '03 CCC has a nice intro article on dynamic balancing for a beginner like me:)
always got for some pukka ALI rods :p but then how many times a year you intending to replace em
the dragster is using em this year @ $300 a rod X 8
but then when the sh1t hits the cylinder on the steel crank needs summat to give a little ;)
Ibiza sport man
03-03-2004, 07:22
The aforementioned "K series crank guru" of Vibration Free did a full balance on my last K engine. It was a joy to rev it afterwards, so smooth. Some mate of mine is going for the Tungsten inserts this season, we'll see what difference it makes, he is revving to 8750. Stranglely enough I heard that just as many of the steel cranks that were breaking as standard ones.
So, to sum up then, you reckon that changing the rods to lighter ones, (provided they can take the load) is a good move ? I was debating whether to go for the light or heavy rods. I guess it depends on what you are like to be revving to ? It would be much more critical to have the light rods on a high revving NA engine than on a high boost turbo engine.
Bernard
Originally posted by max_torque
Basically, if anyone is thinking of serious changes to reciprocating components which are likely to add up to over £1000 (rods @ 150 each, pistons @ 170 each etc), then i recommend you have the entire assembly dynamically balanced by a reputable engine builder, to whom you should supply all the reciprocating / rotating bits, inc front pulley / flywheel / rods / pistons / crank / bearings etc etc.
This way you know its right!
Sounds VERY expensive. Any idea on total cost, and a reputable engine builder with good 1.8T experience?
Ben
Ibiza sport man
03-03-2004, 14:21
Not as expensive as you might think, about £225 + VAT at Vibration Free. Speak to Steve Smith, he'll do the balancing part, but I'm not so sure about the engine build.
Bernard
getting back to original subject, has anyone priced 2litre crank from audi 2litre 20vs?
I believe the 2l crank is about £500 from Audi. I have found a block and crank from a breakers for about £200 though. Bore on the block is already correct, no wear, simple re-hone and stick the JE pistons in... bobs your aunty. Wont cost much more than the 1.8-1.9 re-bore. The only thing is the rods... so I am still debating as to weather I replace the rods and if so go 2l, or if I simply go 1900cc.
It would seem I have fairly strong rods as I have the 210HP S3 motor and not the newer 225's which people have suggested have weaker ones. The thought of 2l and an engine code to match that is rather appealing though! new rods... I doubt I would ever stress the existing rods, but then, if I dont replace em... you know what will break next dont you?
Spoken to Jabba who have said the 2l crank is not up to the power and there are no rods/pistons readily available for the 2l conversion.
The people working on the car seem to disagree. Dont know what I am doing. Seem to be having a mid-life crisis @ 21 :o - I may dump the car, may stick it in storage, may just take the pricey bits - IHI + Manifolds, Gearbox, rims, brakes and get rid of the car. Who knows, that is seeming the best way to go.
I was supposed to buy a house in June, instead bought my coffin on wheels, which luckily blew up before it killed me, but still... I do miss the whooooosshhhhh of 340HP!