S38 + M30 = ?

bahnstormer · Post by **bahnstormer** » Oct 04, 2005 1:18 PM

i posted this on bimmer.info but no one really knew what to say...

will the M5 3.6 head fit on our M30 blocks? the m5 head flows great
and the M30 block is a stout mofo so i'm curious what would it take
to get these two to mate

these are quotes from my E34 manual

first # is for the M30 , second is for the S38

Displacement effective 3430 vs 3535
Compression 9.0 vs 10.0
stroke/bore (in mm) 86/92 vs 86/93.4

russc · Post by **russc** » Oct 04, 2005 1:55 PM

I don't believe so, the water passages don't align(I beleive) along with a host of other problems.

RussC

BDK · Post by **BDK** » Oct 04, 2005 2:55 PM

The S38 head has an extra oil passage that you would have to close off, the S38 block and M30 blocks are almost identical really besides the oil passage that I mentioned above...

Infact the S38 bottom end is stronger than the M30, it's forged and lightened, it is the higher maintenance of the 24V head that makes them "unreliable" as some would say...
why do that???

If you want the performance of the S38 jsut buy one, because if you put the 24V head on a M30 the motor, it would be weaker IMO.....

Now put the 3.8L crank and internals in a M30 and you would have one torquey motor that would outrun a S38 until it came time for topend.....

But street light to street light very few NA cars could touch you

[Edit by BNC on [TIME]1128452244[/TIME]]

BDK · Post by **BDK** » Oct 04, 2005 3:02 PM

also the bore and stroke for the 3.8L is 94.3mm and 90mm at 10.5-1CR but bump it out to 95mm bore and you have a monster M30

[Edit by BNC on [TIME]1128452658[/TIME]]

Tjn182 · Post by **Tjn182** » Oct 04, 2005 3:53 PM

Would that oil passage be blocked by the sheer crushing weight of the head gasket when torqued down? Plus - wouldn't you need the timing chain from the M5 as well? I'm sure there's a buttload of reasons why they won't mate.

BDK · Post by **BDK** » Oct 04, 2005 6:04 PM

Research it yourself if you don't believe me...

But still my questions is WHy do this???

dasMafia · Post by **dasMafia** » Oct 05, 2005 1:16 PM

turbo = way cheaper.

bahnstormer · Post by **bahnstormer** » Oct 05, 2005 11:26 PM

turbo is way cheaper up to a point
following pat p's car he's basically
rebuilding the motor custom so yah
bolt on a turbo, get power, do a HG
get some more, but after that u're really
pushing the whole 2 valve per head thing

ok thanks i was jw about this

Ed · Post by Ed » Oct 07, 2005 4:28 PM

I have heard of one guy who put an M10 head on an S14 short block so it might be possible with enough work and money. Why bother? Used S38s are plentiful enough.

[Edit by Ed on [TIME]1128717394[/TIME]]

bahnstormer · Post by **bahnstormer** » Oct 07, 2005 11:53 PM

there seems to be no point....
i was under the inpression that the m30 block was as strong as u can get...

papajetta · Post by **papajetta** » Oct 08, 2005 6:48 AM

i am actually on the verge of trying this,
i found a cylinder head cheap enough
the main reason to do this is for forced induction purposes.
u would never get the same flow out of the SOHC
so instead of running 20 or 25 PSI to obtain 400rwhp
u might get the same power only running 10 or 12

bahnstormer · Post by **bahnstormer** » Oct 08, 2005 10:35 AM

that is awesome Pjetta, but according to some of the guys on here, the s38 bottom end is stronger than the m30 one, so just go ahead and turbo the s38

unless of course u dont have the bottom?

kenholyoak · Post by **kenholyoak** » Oct 08, 2005 12:01 PM

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[Edit by Ken H. on [TIME]1128988158[/TIME]]

gol10dr1 · Post by **gol10dr1** » Oct 08, 2005 12:17 PM

ken, weren't you the one building that s38 turbo? any pics or progress reports. i believe this could be the first of it's kind in the u.s.

Tammer in Philly · Post by **Tammer in Philly** » Oct 08, 2005 12:45 PM

While "Lucifer's Hammer" will be a fookin' (tm FKB) riot, and I can't wait to see the end product, it's far from the first turbo S38. This car, in particular, has been around for many years and has traded hands a few times ... seems to be holding up quite well. Don't remember who owns it now, it's a few sales removed from original owner Rob Levinson:

http://www.robertlevinson.com/M5_Turbo/

Note that many of the E28 upgrades we all love were pioneered by Rob and a few others, Dinan included, back in the early '90s. The E31/E32/E34 brake upgrade was one of them.

-tammer

[QUOTE="gol10dr1"]ken, weren't you the one building that s38 turbo? any pics or progress reports. i believe this could be the first of it's kind in the u.s.[/QUOTE]

kenholyoak · Post by **kenholyoak** » Oct 08, 2005 1:27 PM

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[Edit by Ken H. on [TIME]1128988217[/TIME]]

graphite · Post by **graphite** » Oct 08, 2005 5:38 PM

Lucifer's Hammer pictures

http://www.doggunracing.com/mye28/lucifers_hammer/

gol10dr1 · Post by **gol10dr1** » Oct 09, 2005 4:41 PM

the attention to detail in this project is simply amazing. question for you, with the tec3, i am guessing that you wired it into the original bosch ecu as a "piggy back" system correct. i assume this from the fact that the tec3r is in the glovebox. on my car, the tec3r was installed in place of the bosch ecu which is all fine and well but the problem is the person who did it (vic sias) does not have sufficient knowledge of anything other than an m3 so some functions on the car dont work correctly. after this incident with vic, i took the car to hp works in colonial beach,va and they completed the install and tuning and also mentioned that they would normally not wire in the tec in such a way b/c there are many functions that are best left to the stock ecu. they leave the stock ecu in and wire the tec3 into it in almost every car that they tune and they have tuned everything from street cars (such as mine) to pro mod drag cars. just a quick question and food for thought.

kenholyoak · Post by **kenholyoak** » Oct 09, 2005 5:07 PM

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[Edit by Ken H. on [TIME]1128988259[/TIME]]

gol10dr1 · Post by **gol10dr1** » Oct 09, 2005 6:52 PM

currently a few things dont work properly on my car and hopefully might be corrected around xmas when i take it back to my new tuner (hp works) for some retuning and a couple other things. the two main things that dont work properly are the ABS and fuel pump. both will stay on after the car is turned off until they completely drain the battery. as a result. i must unplug the battery and leave one door unlocked at all times when i am away from the car. the tach doesn't always work properly (but that was going south before the tec3) and there is a stutter upon deceleration around 2k RPM. hopefully we can get some of this figured out around xmas. word to the wise, take your car to someone who knows what they are doing and not someone who only knows m3!!!!!!!!!! :@

graphite · Post by **graphite** » Oct 09, 2005 7:25 PM

i dont think the ECU has anything to do with the fuel pump being on or off.. it sounds like your fuel pump relay might be stuck closed.. the fuel pump should go on when you turn the key power on... its all controlled by the relay in the fuse box...

Edit: Looking at the schematics there are relays inside the ABS module as well.. and another possibility is the ignition switch.. but it would have to be in the "run" position for those two things to be on which would mean all the internal stuff would be as well (cluster lights, radio etc)..

you could check it by probing with a multimeter the connector on the ABS unit while the problem is occuring.. there is a GREEN wire on the connector into the hydraulic unit.. when the car is off that should have no voltage.. if that has no voltage but the solid red wire in the connector has voltage then it looks like the relay in the hydraulic unit is bad..

[Edit by graphite on [TIME]1128900902[/TIME]]

Tjn182 · Post by **Tjn182** » Oct 10, 2005 11:23 AM

[QUOTE="graphite"]i dont think the ECU has anything to do with the fuel pump being on or off.. [Edit by graphite on [TIME]1128900902[/TIME]][/QUOTE]
Oh yes it does. Back in my old black 535i and with this current turbo 535i, my ECU didn't send the negative ground signal to my fuel pump relay to activate it when the key is turned. I have to ghetto ground the fuel pump relay to turn on with the key (and stay on at all times with the key on).

russc · Post by **russc** » Oct 10, 2005 2:37 PM

On the E34 DME , it does in fact control the fuel pump. It's a rather complicared relay set up with with the ECU grounding the fuel pump relay to turn the pump on/off. I don't know if the DME also does this with the ABS pump, but it may, I don't have that portion of the schematic for the E34.

Andrew, its very important that you get a schematic from the tuner that wired it in. Otherwise you will hate yourself later trying to figure out what they did. It sounds like your guy wired the fuel/ABS in-correctly so their on all the time. Very bad, or, the TEC3 is leaving them on all the time, again, incorrect programming. He should be able to do this correctly, this is basic hookup stuff for the TEC3 install, I would think.

I don't know about the E34, but the tach input on the E28 is not a normal digital logic signal. Its a voltage divider network from the DME. It's very important that the voltage is correct that drives it. Thats another issue your guy should know about to do this install properly.

The stutter could be air bypass, I think. Some of the aftermarket piggyback have compensation for this. Not sure the TEC3 does.

RussC

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S38 + M30 = ?