hey guys,

I am looking into turboing my 2.0 liter m10. it currently has dual dellorto sidedrafts, and i have seen pictures of turbo systems with the carbs. how does this work? how do you control the fuel? and what all would i need to do this. i am not familiar with turbos, so i am trying to gather as much info as possible before i take the plunge, thanks alot yo u guys rock:buttrock

it works as a multi throtle Efi, air flows thru the venturi, and a jet injects fuel into the air stream. For a turbo you will need an air box conecting all four mouths of the carburetors that can be pressurized (either aluminum or steel)

The one in the picture is carbon fiber, two pieces with a latch. Due to this design can't be pressurized

You can control fuel flow, more fuel for more boost by changing the jets of the carburattor. Dellorto and weber have the jets at the top, making them easier to change. The best way to tune it would be to install an air fuel meter and run the car in the Dyno to make the correct adjustment. The adjustment will be more involved than a fuel injected car, due to the jets and needle adjustments, but properly tuned up is very fast

just check the motoGP bikes (pre 4 stroke) 180-190hp out of 500cc

blow thru carb.....mmmm, the only person i know of with a turbo blow thru carb setup is 'otis' on the roadfly forced induction forum.

not really sure what u would need to do to the carbs if anything? i'm guessing at least the jets on the carbs.. :dunno

is the two liter e21 a baby-six or a 4-banger?

yonkers i am kind of confused with what you posted, do the carbureted e21s actually come with two two-barrel carbs? if so that is a lot of combustion for such a small engine

pic up the book <u>Maximum Boost</U> from Corky Bell and it will show what kind of steps to take with a blow through set up.

Originally posted by HellRottRed
is the two liter e21 a baby-six or a 4-banger?

yonkers i am kind of confused with what you posted, do the carbureted e21s actually come with two two-barrel carbs? if so that is a lot of combustion for such a small engine

The 2 liter e21 is actually both my friend. Except the baby m20's never really made a jump to the states except for private import.

And I don't know if the carbed m10s came with a dual carb stock, but I know there are 2 barrel webbers around for them.

It's probably going to be a pain getting the carbs set up right for boost, but it's probably an easier alternative than trying to have to mess with the good old K-jet. You should probably try finding some 2002 boards. Most of the 2002 run was carbed, they didn't add fuel injection until 74 IIRC. And even then, it was an option, not the standard.

Eurospec has a 320 with two Dellorto sidedraft carburetors, that was my answer for. I know all the e21 came with the kjet, but it is not good for mods, it gets really messed up with radical cams (anything over 284), headers, heavy head work, etc.
You can make it work, but for the trouble its cheaper to go the SDS route (efi), or go to sidedraft carbs (Weber, Dellorto, Solex, SU, Keihin, Mikuni)

I know everyone says to keep the stock cam, but would a mild cam work? What are the down sides of it?

you can get a turbo specific cam, I think they have more lift and less overlap (try a 2002 turbo cam)

the ideal turbo cam has relatively low overlap and high lift.....here's TopEnd's specs of their turbo camshaft: ".435 (11.05mm) lift, 272 Intake and 274 exhaust"

i believe the stock cam is .384 (9.75mm) lift & 264 for both intake & exhaust.

Originally posted by M10-POWER
K-Jet works great for forced induction, only thing that messes it up is radical camshafts with lots of overlap. Sidedraft carbs are a pain in the ass to tune on their own, as well as offering too large a surface area which causes driveability issues.

What do you mean as drivability issues? I seen RX7s, VW bugs, and the old bmw 2002 with downdraft and sidedraft carbs and they run fine. I seen them at the autocross and road race, and the street. It takes a little patience or someone knowledgeable on carburetors to tune them (someone fom the old continent or over 50 years old)

Ok, that's what I was getting to. You were runnimg CIS with an audi 5000 turbo warm up regulator (which I think has a pressure port) did it bolt up or you had to do some modifications.
I know i'm asking a lot, but is better to ask questions than fix damaged engine components, don't you think?
As an altrnative to the CIS and aftermarket EFI, what do you think about installing the electronic EFI from the 84-85 BMW 318i

Paul, the problem is, he's running the Euro carbed engine already.

I understand the reasoning behind your arguments, but it'll be a headache for eurospec to change over to CIS.

hey all, thanks for all the info, i am taking all things into consideration now. here are my other thoughts, first off my car pulls hard now, i have taken a cosworth turbo down the highway, and yesterday i lost a mini cooper s coming down from mt etna in our car club "rally":awink:
so anyways, i am thinking either the turbo m10 route, or finding a complete e30 320is(italian m3) and doing an s14 swap. I can pick up a wrecked 320is for about 500$. the question i have is what will need to be done for the s14 swap? my car was never fuel injected, so would the electronics be difficult? i understand the motor bolts in, how about the tranny?

so if you had these choices what would you do

1. blow thru turbo m10

2. s14

3. 185 hp n/a m10

thanks alot guys!

S14 all the way

Either the turbo or the S14.

From what I understand the swap for the S14 should be pretty easy. Only thing is, you're going to have to snag all the fuel injection electronics for it too. But the S14 engine just drops right in to the 2002, so I would think it would be pretty much the same for the e21 considering all three engines use the same block. The transmission might be a little more tricky however. I really don't know tho.

If you want to spend the money to do the s14 go for it, if not turbo the M10, get the CIS unit or EFI.

Hey Paul, I sent you an E-mail about the clutch.