standard lumps how much booooost

[Scrotty]

me again

right, just to round up...
M20 and M30 have generaly lower compression ratio than the norm.so what boost can you safly run without going bang, and at which point has yours gone bang?

some say M20 no more than 9psi....where as some run up to and over 14psi......

soo, for M20 and M30.....with decent intercooler in a decent position, standard block, good fuel etc etc what can one actaly expect to run?and any power outputs at all would be good tanks again

[Turbo-Brown]

8.8:1 M20, easily 20psi!

9.7:1 M20, over 10psi (I've had mine up to 15psi before!)

[WillG]

dunno about easily but yeah 20+psi is possible, depends on tuning, where boost comes in and how well sealed your headgasket is and other stuff. A swedish drag racer made 600hp on stock compression and ran 9 sec 1/4 miles with just a welded diff and radials/steels but I dont know how long it lasted, he was using a autronic ECU, orings and welded head and probly a load of other stuff ive forgoten. I remember he melted a piston tuning it but it was apprently ok after that

[jkarran]

8.8:1 M20, easily 20psi!

My R1 motor's going to be ~8.9:1 and I thought the 11psi I have planned was extravagant.

M20B25 @20psi must be a beast
jk

[Scrotty]

20psi?!
soo, with a bit of head studding, big ass intercooler, correct turbo and all the other stuff thats easier said than done....minus a bankloan for a forged bottom end, i could quite easily get a reliable 270whp from an m20?

what about the m30 then....when you ran 15psi what sort of power were you getting and brief mods if you dont mind

the unanswered question....which is best then (no fighting please) best in reliability and fast road/extremely occasional track day performance?

and what sort of mpg difference is there?assuming both setups had same diff's/wheels/safe maximum boost without blowing up?

[WillG]

if your serious about doing it I suggest you PM ant

[WillG]

this is the drag racer I was on about, check it out http://www.spjuvern.com/

[ShepsEvo3]

I am finding that people are getting braver with boosting thier normally asperated engines. The new Audi S3 has a CR of 9.8:1 and runs 1bar (14.7psi) of boost as standard. Thats 2ltrs with 267BHP standard.

I have been involved with a few Suzuki Swift GTi supercharger conversions. Little 1300cc engines with 10:1 CR and you can boost them to 15psi pretty reliably - but max power needs to be found and the ignition timing retarded so you loose 3-5BHP and the fueling richend up so that another 1/2 BHP is lost to make them 100% reliable. Lower them to 9:1 and 35-40psi is possible (apparently) with the right turbo/supercharger

I am also intending to supercharge a 318is soon, but never seem to get round to doing it . I'd just be looking at 10psi on that though.

The M20 and M30 engines I have no idea what boost they can take, but judging by the CR's they have scope for a fair bit. I know of a very high mileaged E36 M3 3.0ltr with 10psi of supercharged power too which is reliable.

All the conversions I have been involved with have had the biggest intercoolers possible fitted,

I guess anything is possible within reason, but some trick mapping would be called for to keep in check.

[Scrotty]

somone had too many blue smarties
gotta love it though!
im as serious as my budget will let me be....first i have to get the lump and its new bits into me beash....then she'll be getting the turbo treatment.just need to be sure i make the right decisions now with future plans in mind

[Scrotty]

a supercharged swift...whatever next
ill start putting kerosene in my dogs water to make him run faster

[Turbo-Brown]

what about the m30 then....when you ran 15psi what sort of power were you getting and brief mods if you dont mind

It was my M20 (mine's an early high comp motor).

Absolutely no idea on power as it was way before it went on the RR.

Basically, the pressure signal line to the turbo actuators came to rest on an exhaust manifold and burned through so the WGs weren't opening.

It was pretty savage, and I wasn't even going over 1/2 throttle

Wouldn't like to guess how long it'd have lasted like that though.

[ShepsEvo3]

a supercharged swift...whatever next
ill start putting kerosene in my dogs water to make him run faster

You'll laugh, but they are seriously quick when done. I couldn't stop laughing when I roadtested the first one we completed. Also, there are actually quite a few of these out there already, even one or two converted to 4WD using the Subaru Justy running gear.....mental!

[Scrotty]

picture this...
your in ya swift.....pull up next to bignose in his M3 with his slut for a wife riding shotgun....you race down a dual carrige, to show that german ghay a thing or too...only for a lorry to pull out in 2fast 2furious fasion.......wouldnt wana be going soo swiftly then lol human lunchbox
top respect for it...you got bigger balls than me to drive it hard