high compression

[mrtat2k9]

Hello all thank you for looking
Just a matter of interest looking at doing something like this but Has anyone ever don a high compression modification instead of the turbo

[Rusty]

Is this on an NA engine?

[Acidburn]

as he mentioned, yes NA engine.

I've heard it done by the ford boys on turbo cossie lumps but never audi's.

[GazzaG60]

its about revs this one. lots of 16v done but easier to get 4 going fast than 5.

these engines are not the best design so its hard.

you couold do it, go aggressive on the cams and throttle body it and stick with a standard type r civic.

how about a supercharger. my mate did a subaru sport and made a kit for it. with no mapping changes it made 200hp just a fuel mod. think they were 130 or so to start with. was a different but nice drive. issu was the charger type. the owner selected the wrong type but easies to fit a centrafugul type like a procharger. it was a procharger. id have been looking at a lysholm type. they would fit a 5pot inline too, sound like mad max and good for it too. put a second gasket in and an ecu and id say 280hp isn't pout of the question

[Jamo]

Ah stock car no turbo -

[stiglet]

Yes you can raise the compression ratio. Am planning to do this myself, assuming you're talking about an NA engine.

Would advise a remap though!

Take a look on motorgeeks, a few people there are experimenting with this.

As far as power gains go, you won't get all that much more. Maybe 10-15 at a random guess. Although theoretically, it might actually improve your efficiency

[mrtat2k9]

Hi thanks for the replays the engine is the ng model with a 20v head on it and that’s been modified to have mechanical injector put in. Other than that standard on engine side.

To put a super charger on it wouldn’t i need to have low compression pistons?

[Acidburn]

Sounds alot like the coupe gt engine that audibits sold recently (also advertised on pistonheads)

[mrtat2k9]

think that was a kv engine and like you said a gt but was standed other then that iv been on with the poject for about a year. in my spare time had it runing but not got thepower i wanted all does any one know if the s4 5cyl head gasket fit the standad 20v engine.

[stiglet]

Wouldn't advise supercharging AND high compression. Normal compression, yes you can supercharge but only low boost.

[mrtat2k9]

how much bost would i be able to give it and does any one know about the s4 head gasket

[GazzaG60]

standard compression would do it. ideally a few points lower.

the subaru was standard compression. it ran 7psi with no intercooler. they are made of swiss cheese so i think an audi would be ok.

2 stacked gaskets with arps would give you the margin easily. run 10psi with a small intercooler or around 6 without. the important bit is fuel and timing. unless this is controlled properly it will be hard. mechanical is not the way.

having sais that its potentially cheaper to just source an aby. its about being different.

i used to run around 18psi on the corrado G60 with a 65mm pulley. it went as well as a 300hp impreza. ive seen conversions hitting the 300 mark so id exect that would be possible for you, with some engine work.

[Rusty]

just get the pistons skimmed for low boost supercharging. Audiman ran skimmed S2 pistons with silly bhp for ages.

NA tuning is always the same. Cams, flow work, lighten and balance, remap, throttle bodies he you.ve got the money... High compression is fine but you'll need to have it mapped and run decent fuel to get the best out of it and avoid det.

[GazzaG60]

skimming the pistons is a lot more work than stacking gaskets.

i run them myself. skimmed 50 thou IIRC.

you need to remember the ringlands are not so deep on a na piston. i think skimming the na piston will end in tears.

a standard 1.8 16v engine wih 2 stacked gaskets will do 300whp no worries over 400whp has been done with 2 gaskets and a third middle layer.

[mrtat2k9]

I didn’t wont to do a lot of engine work if I could help it a just wanted a little more power then what I’ve got and regards to mapping thought that could only be done on engines with electronic fuel injections and mine in mechanical
Well if high compression not that easy I will look for some thigh that would give me constant boost all the way through the revs does anyone know were I can get one from thanks all for your views