question for anyone who has ever upped their compression ratio

[frag]

if you've upped the compression ratio of your m20, did you upgrade your cooling system? what compression ratio are you running and what did you do?

if i'm not mistaken, the stock compression ratio of the US m20 is about 8.8:1, but what if i go as high as 10:1? do i have to upgrade the cooling?

[digger]

no, but in the philippines you'd want to make sure that it has been retunred to its former glory.

[7pilot]

That high an increase will be beyond the ability of the Factory DME to correctly run the ignition and the fueling.

m

[jlevie]

+1

You would have to have a custom chip made, use a WAR chip, or use a MegaSquirt.

[Wanganstyle]

I have a 10.5:1 compression M20 2.7L being built, Mahle high compression pistons for M20.

if pistons/head are designed for high compression the engine is just fine :)
If original cooling system is 100% new it can take it -BUT upgrade to cooling system is always needed for motorsports use.

Cooling system of e30 should be upgraded ASAP with STOCK engine since you are in the Philippines and the heat and bumper to bumper traffic is INSANE :)


Also, I know from the kind of mountains you guys can drive.......you want upgraded cooling for longevity... :D

I am using a PWR radiator unit for E36M3 in my E30, it is a plug and play affair.

[frag]

thanks for the help guys! most appreciated! :)

digger: unfortunately, i had to restore the car from the ground up (almost). it was in the middle of an engine rebuild when it got caught in the 2009 flood that killed over 700 people. it wasn't a pretty sight, but i count myself as one of the luckiest - none of my family or friends were injured or killed, save for my e30.

after the flood, i had to re-start the rebuild from scratch, and a bunch of other issues came up as well. it took me a long time to get back on it, but i'm finally making some progress. to avoid wasting everyone's time, i won't post the story here. however, i've started blogging about it (apologies to the more hardcore guys who may read it, i'm not the most technical guy out there - i'm just trying to learn my way through) here: pinoypetrolheads.blogspot.com

7piot/jlevie: i am looking into the WAR chip. looks very interesting. my mechanic/tuner recommended it to me, and i'll likely go with his (and your) suggestion.

Wanganstyle: aside from the PWR, any other recommendations? oil coolers? will a switch to an electric fan help? i will likely track the car from time to time, so i think i'll go with your suggestion to upgrade the cooling system. have you been to the philippines? you're spot on with the traffic situation, and the mountain drives. not quite as beautiful or scenic as some of the california mountain roads, but twistier and a more challenging - if for nothing else than the road surfaces tend to change every few hundred yards.

thanks fellas!

[SkiFree]

Surprised nobody has asked, what octane will you be running? Highest c/r I'd on 91octane would be close to 9.75;1 MAX.


Interesting story about the car though. Cool to hear you're breathing new life into her.

[325ix]

Brand new cars have a higher c/r and run on 91 then 9.5

[Wanganstyle]

I love your country:) have a lot of good friends in Manila; client there as well :) last time I got to drive the mountains between tagatay and botangas, very twisty and lots of elevation!

Oil cooler is needed, you don't need a thermostat for oil.

Stock electric fan is v good, the mechanical one is needed also, i'd keep it and make sure it's 100%

With the high octane avail in mnl (95-100oct) compression ratio won't be a problem.

My m20 was 10.5:1 cr 1985 spec and did pass smog in California on 91 poo!

S54 Oem is 11.5:1 and survives to wangan heavy duty on Cali 91 poo

[frag]

SkiFree: thanks for the encouragement! it's been a tough ride so far. and good point on the fuels. i didn't think about that, but fortunately, as Wanganstyle said, we have pretty high octane levels here, and just about all pumps here carry at least 95 octane, with one company offering 100-octane. honestly don't know why, we just do.

but related to the fuel question, will 10% ethanol have any effect? most fuels here are now E10.

Wanganstyle: thanks for the tip. better start researching on the oil cooler and higher rated radiator. when you said the e36 M3 unit was plug-and-play, does that mean it's got the same dimensions as the stock e30 unit? why did you opt for that one then? sorry for all the questions, but i'm very much a novice at this.

look me up if you go to manila next! tagaytay-batangas is a good run, and is a staple with car enthusiasts here. hopefully i can take you to sierra madre, which is totally up the side of a mountain, with tighter twisties and a better view.

[Wanganstyle]

Sounds good!! I would love to drive more next time I visit the phils-

I posted a e36m radiator into early model FAQ on this section of forum with pictures etc, slight adaptation needed got 84-87 e30's (my e30 is 1987)

If your e30 is 1988+ then the RAdiator is same part number as e36; any aftermarket big radiator e36 item will fit directly :)

http://www.r3vlimited.com/board/showthread.php?t=214798

[frag]

mine is a 1990 production, so it should be a perfect fit. thanks man!

[nando]

10:1 should be just fine on US premium fuel. you just need a tune. you can't expect to sigificantly change the engine's characterstics and leave the ignition totally stock.

I had plans on 11:1 with a schrick 288. I wasn't even *close* to detonating with 10:1 and a schrick 284/272. MBT was 7-12 degrees from the knock threshold. There's plenty of headroom..

as far as cooling - it's probably warmer in the phillipines, but I don't think the M20 radiator is too small. It's more of a matter of making sure everything is in good working order. New or good condition stock parts should be fine for any N/A M20.

[SkiFree]

10:1 should be just fine on US premium fuel. you just need a tune. you can't expect to sigificantly change the engine's characterstics and leave the ignition totally stock.

I had plans on 11:1 with a schrick 288. I wasn't even *close* to detonating with 10:1 and a schrick 284/272. MBT was 7-12 degrees from the knock threshold. There's plenty of headroom..

Interesting, maybe I'm just a little conservative then.

[blefevre]

Surprised nobody has asked, what octane will you be running? Highest c/r I'd on 91octane would be close to 9.75;1 MAX.


Interesting story about the car though. Cool to hear you're breathing new life into her.

New cars are in the 10's and 11's and run normal fuel. The fuel is fine, it's all about the tune/engine build.