M42 turbo fact thread

[Dj Buttchug]

fuuuuuuuu I need to finish my intake so I can up the boost!!!

[e30guydownunder]

More Info:










Better pics and such when I have time, busy preparing it for the Mattara Hillclimb this October long weekend. I am running in the club day event on the Monday because all my mates are but anyway.

So Basic Specs:

BMW M42 (1.8L 4 Cylinder)
CP Pistons
ARP Rod Bolts, Main Studs, Oversize Headstuds
O-ringed Head and Block, Copper Headgasket
Cat Cams, VAC Motorsport Springs and Retainers
Custom Rear Sump
Garret GT3076R, 0.63 Rear Housing, Tial MVR 44 on custom Manifold
DTA S60 still running the show
Fuel Cell, 2 x 044's, 1600 Bosch Injectors and a bunch of other supporting mods.

I have changed to a Getrag G260 (325i trans) overdrive transmission and a 3.46 rear end, this is good for a touch over 200 in 4th and should mean I don't have to change to 5th at Wakefield.

There has been a whole pile of background developments but they are for later. Right now I am going to drive the wheels off this thing and put the development program on hold, I am well sick of wrenching.

[MF DOOM]

high five dude




EDIT: Your thread name is hilarious!

[e30guydownunder]

Yeah I figured it might get some reactions that way :p New video in my thread

[Dj Buttchug]

^extremely well done man, and very impressive

[ccsdo5]

Howdy so I figured this thread gets more traffic than my silly project thread. I just got through pulling my motor and what not so now is the time to decide what I want to do with it. My goals are 250-300whp, but I would like to know I could maybe go a little more in the future so I wanna just build my motor up now while it's already out. Here is what I was thinking:

-85mm overbore
-Arrow precision forged H-Beam connecting rods
-CP 8:5:1 forged pistons
-MLS head gasket (.70)
-ARP Head stud kit
-One piece forged stainless steel valves (7mm)
-Steel alloy retainers
-Dual interference springs
-Spring seats
-Polished and balanced OEM crank
-Ported and polished head

My biggest concerns are should I use the same camshafts? Or is it totally worth it to get the VAC camshafts for turbocharged motors.. Also what should I be looking at for main bearings and rod bearings. Does anyone know if there are acl racing bearings for the m42 or a good set I could get.

Here are the links to everything I was looking at from VAC:

http://store.vacmotorsports.com/vac-...-kit-p244.aspx

The M42 turbo kit which includes
-Pistons
-H-Beam connecting rods
-MLS gasket
-ARP head stud kit

http://store.vacmotorsports.com/vac-...ock-p1022.aspx

The valve kit I'm looking at.

http://store.vacmotorsports.com/vac-...pcs-p1014.aspx

The valve spring and retainer kit which has
-springs
-valve retainers
-spring seats

http://store.vacmotorsports.com/vac---m42-performance-race-turbo--supercharged-camshaft-sets-p1930.aspx

-M42 performance turbo camshaft set

Thanks for your help in advance!!

[MF DOOM]

You pretty much just described my engine. Cams would be worth it. I see a noticeable drop off after 6k and its almost not worth revving passed 6.5k. Talk to them about how much boost you plan to run. When I talked to them last they were getting a quote for me for some custom cams, they never got back to me btw, but depending on boost level and how high you want to rev they can set you up with more desirable cam specs than what is listed.

[Dj Buttchug]

fwiw ccsdo5, you dont really need to fork out extra money for rods. Stock m42 rods are insanely strong.

[MF DOOM]

And I have some low mileage ones i'll sell you :)

[wazzu70]

The VAC cams will definitely spool faster and add more power than the wimpy OEM cams. Our factory cams are pretty weak sauce!

[gearheadE30]

Man, I've been perfectly happy driving my turbo M42 the way it is, and now you all have me wanting to start fiddling with it again and try to get more power...

[pantelones]

You pretty much just described my engine. Cams would be worth it. I see a noticeable drop off after 6k and its almost not worth revving passed 6.5k. Talk to them about how much boost you plan to run. When I talked to them last they were getting a quote for me for some custom cams, they never got back to me btw, but depending on boost level and how high you want to rev they can set you up with more desirable cam specs than what is listed.

^^^ There is soooo much more that goes into a turbo cam than that!

Custom cams, custom cams, custom cams...

Back-pressure, RPM range, boost level, target horsepower, A/R of turbo, turbo frame (T3, T4, T6/Thumper), head flow, cubic inches, and even location of turbo...etc. All of these factors are extremely important in determining the cam that best suits your needs. There is no rule of thumb with a turbo cam. There are too many variables and the only way to get the right cam is to take all of those your parameters into consideration, and only then can a proper cam be selected.

http://www.forcedinductions.com/help.htm

In truth, Godbold says 99 percent of Comp Cams' turbo grinds should be custom profiles because "pressure differential can be all over the place. The reason we don't have a lot of catalog turbo cams is because there are not a lot of catalog turbo systems." Every turbo installation is unique.

http://www.hotrod.com/pitstop/hrdp_1...s/viewall.html


And for shits and giggles, put your calculus skills to work?

http://www.tildentechnologies.com/Cams/index.html

[bmwm42]

What about attitude atmospheric pressure outside air temp density of fuel all this shit impacts your turbo build and should be considered when deciding your cam grind for your build

[///digitalme]

Hi guys I'm new to this turbo thing. I'm getting to the point where I want my car to be. My engine is healthy. Full timing overhaul im thinking of getting it turbocharged. What's a realistic number of cost. My goal is atleast 160-190hp. Sorry about my noob questions lol also trying to keep cost low using stock internals.

[wazzu70]

^^^ There is soooo much more that goes into a turbo cam than that!

Custom cams, custom cams, custom cams...

http://www.forcedinductions.com/help.htm

http://www.hotrod.com/pitstop/hrdp_1011_cams_for_turbocharged_engines/viewall.html

And for shits and giggles, put your calculus skills to work?


http://www.tildentechnologies.com/Cams/index.html

This is true of atmo cams. If you want it to be perfect it needs to be custom ground for your specific application. Even then, you can buy sport, rally, ect cams.

The VAC turbo grinds are a great all around grind that will work with most setups. Like all turbo cams you need a free flowing exhaust to really make them shine (no log mani, no rediculiously small turbine housing). The grinds aren't 100% perfect for all applications but its still leauges ahead of using stock garbage :)