E30 Zone

Ive looked into turboing the m20 engine on e30tech and ive got a pretty good idea of everthing.

My question is regarding the stock internals. It seems that all the turbo'd m20's on that forum would be the lower compression version.

How would you go about turboing the higher compression engine on a budget? Or would it be a set of pistons needed to lower the compression?

thanks

MLS gasket lowers compression, I´ve done that a few times and it´s always worked out great.

Thanks, out of interest what boost did you go upto using the gasket?

I have seen 1.5bar boost on such a setup.

Thats good, i would be planning no more than 1 bar of boost anyways. Did you o ring the block aswell with the mls gasket?

Nope, that is not needed when using a MLS gasket as it´s infact all steel

did u do anything with the head/bottom end at all or literally just crack open the engine, stick in the MLS gasket and run 1.5 bar? with tuning ofcourse..

that´s exactly the case.

On engines with 8.8:1 compression, it´s even enough to just remove the headbolts and replace with ARP studs with the head ON.

I´d drain the block of coolant from the side bolt on the exhaust side when doing that.

Tuning is the major factor in longevity of course.

sweeeeeeeeeeeet.. thats my long term plan sorted then. ive already got a solid 7-8psi tune to start off with when the time comes so really just a matter of getting the bits.

any idea how much boost would be pushing my luck on the original headgasket/studs? havent been able to find much info on 2.5 turbo's, most seem to go the stroker turbo route and mess with compression. i was originally thinking no more than 7-8psi without a decent gasket and studs.

also would there be any issues taking the turbo's oil supply from the fitting for the oil cooler lines on the side of the block? was thinking it could basically be run in line with the cooler, probably on the return side of the cooler..

Those lines are controlled by a thermostat, so don´t do that.

it´s not the amount of boost that will hinder you getting more power but the cylinder pressure / torque output.

So if you don´t have to much boost or torque in the low end I think 280-300hp should be pretty easily gotten on stock stuff.

What turbo do you have? If you have a good electronic boost controller then you can adjust the boost against rpm and massage the torque output that way.

no turbo yet.. have been undecided on what to do with the engine.

low end is pretty good as is so boost in the higher RPM's would probably be what id be looking at doing. how low are u talking about? like sub 3000rpm? maybe run like 7-8psi lower down and up to like 10psi higher up or something then?

yes.

Something like that

@ gunni, i've been thinking about going down the turbo route as a project over the winter months & what i would like to know is where can i get a MLS head gasket for the m20b25?

link??

many places. I personally don´t stock them but I think Ant does.

Gunni, u seem to know a fair bit on boosting an otherwise standard B25 so may as well pick ur brain while ur here

would i actually need an electronic boost controller to keep the low end from getting too much boost or could a manual controller + the lag on the turbo suffice for an 8-10psi setup? could upgrade to electronic and do ARP studs/MLS gasket when i want to go above 10psi unless its a necessity even at 10psi or less.

it depends on the turbo you decide on running .

if you use a manual controller it will not be able to settle boost the same in each gear. so if you floor it at 2.5k i 5th gear it will have more time to reach the boost controllers target boost.

ideally you would simply run a low spring pressure to keep max boost down anyway

turbo wise it would probably be either something OEM from a turbo car, maybe a scooby turbo or a T3 or something like that..

was actually wondering about boost delivery in different gears.. spring pressure? u talking in the dumpvalve or wastegate? i was thinking wastegate set at 7-8psi to start off with.

wheres a good place to take the oil feed from and fit the return line?

actually been thinking about a rear mount turbo setup.. i could run an electric oil pump in the boot and keep everything on the back of the car bar the boost pipes from the turbo to the engine.

absolutely forget a rear mount turbo.

I´m talking about the wastegate, I´d suggest you just run a 7-8psi spring in that to begin with. When you are ready for more boost then run a higher spring or manual boost controller, allowing for higher low end.

take the oil feed from the oil pressure sensor port.

A scooby turbo should work fine to same power as the scoobies use them to

hear stories about lag with rear mounts but from what i can tell it all depends on how u build it. not needing an intercooler would be a plus..

was thinking wastegate but i havent got any real experience with turbo setups. thats the plan anyway.. wastegate set at 7-8psi to start off with and load up my 7-8psi tune and run the size of injectors recommended with the tune (24lb).

would be interestign to see how easy/hard it would be to get my MAF conversion working with boost.

I was involved in a rear mount turbo for a 205 GTi. Certainly worked well and lag wasn't an issue. Oil starvation was though...

An intercooler was used (from a BMW 320d), and placed underneath the car laying flat.

did u run lines fron the engine bay back to the turbo?

i was thinking if i built a rear mount id probably run an electric pump and small resivoir in the boot. with the turbo that far back and fed by its own oil supply i doubt id be needing an intercooler as id think the filter being at the rear somewhere and all the intake piping from the turbo to the engine would keep the air nice and cool already.

i really only like the rear mounts purely for the obnoxious turbo whistle u get having the turbo so close to the end of the exhaust system tho