1.9 8v Using 1.6 Pistons. Cr?

[MerlinGTI 3]

I would like to know the Compression ratio of a 1.9XU 8v that uses 1.6XU pistons. Does anyone know what it is? or could a kind soul work it out please?

 

Ive tried googling the calculators for this on google and theres way to many measurements I dont know etc.. To be honest its all a bit over my head

 

Cheers

[mattbenselin 0]

CR 11.1 give or take buddy.

 

Have a word with DamirGTI he has done this with success.

Edited October 4, 2009 by mattbenselin

[welshpug 1,626]

you need to find the compression height and dish volume of the 1.6 pistons and compare that top that of the 1.9.

 

then have a go at working them out with the following info http://www.pumaracing.co.uk/CAPACITY.htm

 

don't forget the 84mm bore 1.6mm thick gasket, head capacity IIRC is 32cc on the 8 valve heads.

[DamirGTI 327]

Few posts regarding this subject where deleted from the forum database ..

 

Anyway , it'll be around 11.1 , or perhaps a little bit higher im not sure petert will know this precisely ..

 

1.9 8v head combustion chamber volume - 34cc

1.6 (and 1.9 DFZ) piston dish volume - 9cc

1.6 (and 1.9 DFZ) piston compression height - 37.5mm

 

1.9 D6B piston dish volume - 15cc

1.9 D6B piston compression height - 35.5mm (if im not mistaken ..)

 

Damir

Edited October 4, 2009 by DamirGTI

[MerlinGTI 3]

brilliant, thankyou gents

[edbar 6]

mines at 11.5-1 with skimming aswell.

[Baz 421]

Perfect for a suitably lumpy stick then!

[edbar 6]

oh yes works well with the lumpy stick in!

[vickiw106 1]

mines at 11.5-1 with skimming aswell.

 

 

is this cr ok for standard rings

[James_R 3]

It would more be the crown melting for the increased temps, but it's about the limit really.

[RalliArt 0]

Few posts regarding this subject where deleted from the forum database ..

 

Anyway , it'll be around 11.1 , or perhaps a little bit higher im not sure petert will know this precisely ..

 

1.9 8v head combustion chamber volume - 34cc

1.6 (and 1.9 DFZ) piston dish volume - 9cc

1.6 (and 1.9 DFZ) piston compression height - 37.5mm

 

1.9 D6B piston dish volume - 15cc

1.9 D6B piston compression height - 35.5mm (if im not mistaken ..)

 

Damir

Damir, don't you think you are forgetting the head gasket volume witch is about 5cc and calculating the CR with this method http://www.pumaracing.co.uk/CAPACITY.htm i think for you to get about 11:1 CR you will need your "clearance volume" to be 39.5 cc, correct me if I'm wrong, this is in my calculation....

Tisho!

[DamirGTI 327]

.. dunno i'm crap with math , i've never done calculating regarding this matter as i simply couldn't be bothered , but based on petert's posts over here (hes built a few engines on the same basis) said to be around 11.1 ..

 

Damir

[RalliArt 0]

OK Damir, I agree, that was just a thought

[petert 554]

I use a program called DCR Calculator. Just plug in the values. Hopefully it's right! There's plenty of similar ones available on the web.

Edited October 27, 2009 by petert

[RalliArt 0]

OK Petert I've tried the program, i convert all measurements but the program calculate my SCR (Static CR) is 4.7, can you tell me in the box where it writes Stroke-check box for Dynamic stroke what will you write for 1.6 engines 73mm stroke....

[davidc 0]

mines at 11.5-1 with skimming aswell.

 

Do you know how much you skimmed off the head & Is there a dimension you can measure on the head & compare to std (so I know if our head is an unskimmed original).

 

 

Cheers,

David

[powermandan 0]

What sort of power would you expect out of this engine with a lumpy cam and carbs? assuming this wont run on standard management.

Edited February 17, 2010 by powermandan

[MerlinGTI 3]

What sort of power would you expect out of this engine with a lumpy cam and carbs? assuming this wont run on standard management.

 

Damir sucessfully runs (ran?) 1.6 pistons on std management, but the dizzy needs re-weighting/re-springing/what ever to cope with the advance. IIRC he also found some IGN AMPs to cope with this better than others (marelli magnetti was the best I think).

 

You cant go to lumpy on std management, I think (im no expert) much more than 285 is a no go.

 

I will be happy with 130 ATW on std injection, 150ish ATW on 45's. Thats if I ever finish building this bloody engine I dont know how realistic these figures are, but im not statistic obcessed. If it scares me when I floor it I will be happy.

[blackpug 0]

Im running this setup on standard injection and a newman road rally cam no problem, havent had it rr'd so dunno what it's putting out. Also using an ign amp from an mi16 (extra pin?) if that makes any difference

[MerlinGTI 3]

The extra pin isnt an issue.

 

Its been a while since I was looking at Ignition amps, but theres 5 and 7 pin vairiants IIRC. The 7 pin is actually a 6 pin in most cases, the 7th pin is for some read out that 205's dont utilize.

 

The same amps were used on may other jettronic cars like BMW's and Golfs, hence all the confusion.

[DamirGTI 327]

.. the 7th pin is for some read out that 205's dont utilize.

 

It's "tacho out" signal and yes , it's unused on both the Jetronic and Motronic management ..

 

Damir