2088cc 8v Turbo

[powermandan 0]

So how do i go about getting 2088cc in my iron block 8v turbo?

 

is it just a matter of dropping a 1.9 crank in?

 

will i retain my normal compression?

 

thanks

 

Dan

[stefan 4]

yes you fit the 1.9 crank, and overbore the liners to the desired spec.

you will not retain your normal compression because of the longer stroke, the pistons will protrude for the 0.2 difference in stroke.

 

strokexsqare of borex3.1416=capacity

Edited July 8, 2010 by stefan

[powermandan 0]

i didt realise that id have to overbore the block.

[welshpug 1,661]

you will if you want 2088cc ( I make it 2092 actually?!)

 

88mm stroke on an 86mm bore is 2044cc.

 

either way if your pistons are intended for an 86mm stroke they will need some material removing to lower the compression back down to the same figure, of course you could leave it as it is as it wont be that high.

[danpug 1]

The 2.0 turbo is quite low compression anyway so as long as it didn't go up by too much it should be fine.

[stefan 4]

Removing the material from the pistons weakens them, it isn't the best way round.

With the same pistons you're compression ratio will raise somewhere roughly around 9.5:1, wich isn't so good for a turbo engine.

A proper thicker head gasket could do the yob.

Personaly I wouldn't bother increasing the capacity, cause with the turbo, there's so much more that can be done.

Edited July 8, 2010 by stefan

[powermandan 0]

Are there any off the shelf pistons I can use?

[tony perks 1]

can you not just use the 1900 shorter rods?

[welshpug 1,661]

they are 9mm shorter, isn't that a bit much for just a 2mm increase in stroke?

[powermandan 0]

tbh im completely out of my depth, was just hoping that if im going to go through all of the trouble of rebuilding the bottom end i could make some improvement.

 

Where are you getting all of the size information from?

[tony perks 1]

they are 9mm shorter, isn't that a bit much for just a 2mm increase in stroke?

 

9mm i didnt realise they were that much shorter, are the crown heights shorter on the xu 10 then?

[DrSarty 90 1 Cars]

tbh im completely out of my depth, was just hoping that if im going to go through all of the trouble of rebuilding the bottom end i could make some improvement.

 

Where are you getting all of the size information from?

 

Engine reboring, plus piston work all starts to add up your costs.

 

The size information is from several sources, e.g. even the Haynes manual and internet can tell you the bore and stroke of your engine and we've taken them apart before.

 

Plus Welshpug knows all the figures.

 

If you want 'improvement' I would first set the budget you can afford. You will perhaps be better off really rebuilding the bottom end well, i.e. taking no short cuts, and installing everything to a high standard to make the best of what you have.

 

Stefan>

No liners. It's an iron block.

[welshpug 1,661]

naah, taller blocks (11mm ish)

 

 

powermandan, the info comes from what we learn on these pages, in the Haynes manuals, servicebox data, as well as tinkering with pugs for a looong time

[stefan 4]

Stefan>

No liners. It's an iron block.

 

 

My appologies, translation error, for me cylinders=liners

Edited July 9, 2010 by stefan

[powermandan 0]

Cheers guys, well im not sure of my budget yet. It seems to be increasing rapidly. I really want to build summit special. been promising myself i would for years now.

 

While were on the subject on liners/bores etc. Im breaking the engine down next week, not sure of the mileage etc. what are my options if the bores are overly warn. can i get the block honed and fit oversized rings?. At what point do the bores become overly warn?

 

Thanks

 

Dan

[carbers205 1]

Thats odd, I ended up with 2092cc rather than 2088cc too for 87mm bore and 88mm stroke.

Anyway when I did it we just took 1mm off the piston crowns which was great for my n/a engine as the comp did up slightly. We didnt have any problems in taking that amount off.

The block can be honed by a good machine shop, but Im afraid I dont know the tolerances. It is possible to get new pistons in 86.5mm though so maybe larger rings wouldnt do the job? Im sure someone else will confirm this.

[DrSarty 90 1 Cars]

Displacement of an engine is apparently only just swept volume; chamber volume etc doesn't come into it.

 

Therefore it's just a case of whether your working out is accurate:

 

87mm (rebored block) / 2 and then squared (i.e. [87/2]^2) = 1,892.25

 

1892.25 x Pi (22/7) = 5,947.071

 

Multiply by stroke (crank throw - 88mm) = 523,342.286

 

Multiply by no. of cylinders (4) = 2,093,369

 

This is in mm^3, so to put it into cc^3 (cubic centimetres) just divide by 1,000 = 2,093cc. So it's a 2.1L.

 

The standard bore engine (block/cylinders not rebored) gives 2,045cc. I'm not sure where 2,088cc comes from, unless I'm missing something.

 

I did it manually as above, but here's a little online toy: CLICK

Edited July 9, 2010 by DrSarty

[omega 82]

 

unless I'm missing something.

[stefan 4]

Displacement of an engine is apparently only just swept volume; chamber volume etc doesn't come into it.

 

Therefore it's just a case of whether your working out is accurate:

 

87mm (rebored block) / 2 and then squared (i.e. [87/2]^2) = 1,892.25

 

1892.25 x Pi (22/7) = 5,947.071

 

Multiply by stroke (crank throw - 88mm) = 523,342.286

 

Multiply by no. of cylinders (4) = 2,093,369

 

This is in mm^3, so to put it into cc^3 (cubic centimetres) just divide by 1,000 = 2,093cc. So it's a 2.1L.

 

The standard bore engine (block/cylinders not rebored) gives 2,045cc. I'm not sure where 2,088cc comes from, unless I'm missing something.

 

I did it manually as above, but here's a little online toy: CLICK

 

You're not missing anything ,your calculation is accurate, but needlessly long, I use a shorter procedure because it's a 4 cylinder engine:

 

stroke x square of bore x 3.1416=displacement

8.8 x square of 8.7 x 3.1416=2092.5cc

Edited July 9, 2010 by stefan

[DrSarty 90 1 Cars]

I was showing how it's worked out Stefan, not necessarily the shortest method, as that doesn't explain what's going on.

[carbers205 1]

The 2088cc came from the pinned topic on bottom ends for what its worth.