M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Swaps, Turbos, Buildups => Topic started by: ShepsM3 on December 28, 2007, 06:33:38 PM
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Hi all,
I am new here, but am quite active on a few other BMW forums. I have a few 318is M42's as project cars and I have just purchased one which I would love to Supercharge. I want to use a Rotrex Centrifugal Supercharger as I know them pretty well having converted a few other cars. They give damn good results and are very compact and reliable.
What I want to know is, how strong is the M42 engine for taking boost? I don't really want to play around with the internals and just want to bolt the Rotrex on, large front mount intercooler, raising rate with boost fuel pressure regulator and loose the AFM through using the latest Dastek's Unichip version Q and use a MAP sensor instead. May go larger injectors too, depending on how off the fueling is under boost. I would love to push 10-12psi if the internals can take it?
I understand that the crank and rods are steal and the pistons are forged already, so BMW did the hard work here. I am not worried about the high compression ratio either, but am worried about the top piston rings and head gasket.
I also know that in order to carry out this conversion, I have to upgrade the crank pulleys and water pump, alternator pulleys for the later M44 type to be able to use a multi-vee belt for the supercharger. I will mount the SC where the AC pump would have gone if it was fitted.
I have done a quick search, but its late here and I thought some of you guys maybe interested in what I want to do and offer some advice up before I go ahead.
Thanks in advance.
Paul :D
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here is my experience with my turbo m42. My car has a stage colder plugs and the thickest headgasket you can buy from the bmw dealer, I forgot the actual thickness. I have been through a few setups already but I use to run about 6psi with the stock injectors and a rising rate, my injectors were maxed out and it started running really lean at about 7psi. It ran good then but i kept getting beat and needed more power. So now i have 42lb injectors and run about 10-11 psi on the same setup. As far as tuning goes, i have the stock ecu, factory timing and everything, all i did was mess around with the mass airflow a little bit rev it up in the garage a couple times to make sure it wasnt huffing black smoke and left it. For some reason it ended up working pretty well for over 30k miles. I dont see any problems running 12lbs or more with a good tune and knocking back the timing.
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here is my experience with my turbo m42. My car has a stage colder plugs and the thickest headgasket you can buy from the bmw dealer, I forgot the actual thickness. I have been through a few setups already but I use to run about 6psi with the stock injectors and a rising rate, my injectors were maxed out and it started running really lean at about 7psi. It ran good then but i kept getting beat and needed more power. So now i have 42lb injectors and run about 10-11 psi on the same setup. As far as tuning goes, i have the stock ecu, factory timing and everything, all i did was mess around with the mass airflow a little bit rev it up in the garage a couple times to make sure it wasnt huffing black smoke and left it. For some reason it ended up working pretty well for over 30k miles. I dont see any problems running 12lbs or more with a good tune and knocking back the timing.
That sounds good, I am suprised it's not pinging with standard ignition timing though, how much thicker is the head gasket to the one you took off?
Ok looks like the injectors will be the limiting factor here. Does anyone know what cc the standard ones are?
Whats the limit boost wise for these engine with standard internals, assuming the head isn't comming off yet?
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That sounds good, I am suprised it's not pinging with standard ignition timing though, how much thicker is the head gasket to the one you took off?
Ok looks like the injectors will be the limiting factor here. Does anyone know what cc the standard ones are?
Whats the limit boost wise for these engine with standard internals, assuming the head isn't comming off yet?
hi on E30 m42 standard injectrors are 215cc , with standard internals , m42 can take 0,7 bar of boost in 10:1 cr without of problems ,but you must tune afr ratio and advance retart sheets with SMT6 pigiback or somthing else megasquirt and more if you do everithing write you must have 270-280 hp and 320-340 NM. on engine
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looking forward to this paul! btw m42 pistons aren't forged iirc. look forward to seeing you soonish with the latest tweaks to mine (if i hang onto it) :)
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hi on E30 m42 standard injectrors are 215cc , with standard internals , m42 can take 0,7 bar of boost in 10:5 cr without of problems ,but you must tune afr ratio and advance retart sheets with SMT6 pigiback or somthing else megasquirt and more if you do everithing write you must have 270-280 hp and 320-340 NM. on engine
That sounds great! I thought the standard injectors were only 170cc - which I thought was a bit low for a standard 318is. Also are they really 10.5:1? Again, I read somewhere they are 10:1... My info could be wrong though?
Hi Tim... I'm looking forward to it too lol. I've been looking for a low mileaged 318is for a while quietly and got this one pretty cheap, but it needs work in the suspension area and some bodywork too. I've also found it pretty dire on fuel too compared to my mothers. Can get 34mpg on a very gentle long run, but driving with some spirit drops it to 26-27mpg. I was getting more than that out of my M3!! I am not too worried about the fuel economy, but I want issues like this sorted as I think something is slightly amis, certainly before I start forcing air through the intake! lol Want to talk to you about painting my Cam cover and intake manifold too, you did a neat job of yours!
Looking forward to seeing you again.... and lets crack 200bhp this time ;)
EDIT:: Oh BTW, Appletree from the E30Zone I am sure said the standard M42 pistons were forged?? Or have I got everything wrong about this car? LOL.
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Also are they really 10.5:1? Again, I read somewhere they are 10:1... My info could be wrong though?
The compression is 10:1, think that was probably just a typo.
EDIT:: Oh BTW, Appletree from the E30Zone I am sure said the standard M42 pistons were forged?? Or have I got everything wrong about this car? LOL.
Im pretty sure the pistons are not forged. Basically the only bit that isnt.
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Thanks An318is,
If they are not forged, I guess that gives me an excuse to get in there and enlarge the displacement too ;)
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Sorry for cr :eek::eek:,they are two modifications он м42 10,5:1 and 10:1 the diferense are in piston forehead.
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The motor I built is not a complete basis for comparison as it's custom pistons and a lower CR but I do have stock rods. We had a problem with the wastegate while on the track last time and were seeing up to 27psi. There appear to be no long terms effects and we've had the car back on the dyno since then. It's making the same numbers without coolant leaks, oil consumption, or any temp problems.
The quick answer is that the block and heads will take boost.
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The motor I built is not a complete basis for comparison as it's custom pistons and a lower CR but I do have stock rods. We had a problem with the wastegate while on the track last time and were seeing up to 27psi. There appear to be no long terms effects and we've had the car back on the dyno since then. It's making the same numbers without coolant leaks, oil consumption, or any temp problems.
The quick answer is that the block and heads will take boost.
Rob, is your headgasket, headbolts and everything except pistons standard? What CR did you end up with and who's pistons did you use? Any links to it?
27psi is going some! :D
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We were not happy with 27. I designed the setup to run up to about 23 but can hit our HP goals well below that. We're using ARP head studs and a MLS head gasket. The pistons are 8.5:1.
Here is a link http://www.r3vlimited.com/board/showthread.php?t=96456
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Thanks Rob, makes for some interesting reading. I think I'd like to keep the high CR but if I need to change the pistons to forged ones I would probably just go down to 9.5:1 to make the car nice and driveable down at low RPM's. The SC I will be using is a Rotrex centrifugal type, so increases boost with RPM. Obviously the ARP Head studs and a nicer head gasket is the way to go. Also while I am there I will replace the big end and main bearing cap bolts/studs? with ARP items too.
Power wise, I want to see around 275BHP at the flywheel. So maybe I may need to loose some CR to run a bit more boost than 10psi, although I don't think I will be far away?
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I honestly don't remember if we could find main and end cap ARP bolts, but if you can then get them. I think you'll need to run more than 12psi to make the power you would like. You're also going to have to think about injectors, fuel pressure, and regulating fuel. If the engine is solid now, I'd recommending you run it at 8-10psi until you blow a head gasket and then worry about the upgrades on the rebuild.
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i found this about the m42
http://www.esatclear.ie/~bpurcell/318isengine.html
it says
forged crank, forged rods, but only lightened pistons.
also says compression is 10.1 nothing about 10.5.1
and injectors are 173cc
but who says this site is correct?
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I was baseing the figures on what I have seen on previous NA cars I have converted to FI using the Rotrex SC. Usually I see 60% increase with 6psi of boost once the management has been live mapped on the rolling road (by me). Depending on how well the head flows and how good the exhaust is, 12psi I can usually double stock power. But maybe I am lucky to have achieved this so far?
Yes, Injectors are very limited, also I would use a rising rate with boost FPR. Probably uprate the fuel pump, although the standard one will probably be upto the job.
I am looking to fit as large but thin as possible intercooler with large "face" surface area for optimum charge cooling, so inlet temps should stay nice and low.
I am hoping the head gasket or engine doesn't blow. I would like a reliable car right from the word go, so I will look into better head gaskets and ARP head studs/nuts. I am not liking the idea of running the car with non forged pistons though. I was hopeing they would be forged as standard.... can't have everything lol.
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I just came upon a DASC that is totally unmodified.
I plan on installing it as is and doing a dyno run to see where the numbers and AFR baselines come in.
My plan from that point is to try the cheater CR decrease with a thicker head gasket, but I am trying to find out how thick I can go without ruining the quench and the ability of the combustion chamber to efficiently burn the charge.
Does anyone know anything about that? How thick can I go?
Also, is a smaller pulley all I have to do to increase boost?
What about the bypass thing on here? It is not like anything I have ever seen but apparently popular on these Eaton blowers. It returns excess boost back in to the blower. Pretty smart design, but I imagine it has to be modified to ensure the increased boost goes where it needs to.
I will also be doing away with the AFM and run a Megasquirt off of MAP with larger injectors. Probably going to shoot for 10-11 psi. Any idea what injector size I should install?
Thoughts?
J.
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I will also be doing away with the AFM and run a Megasquirt off of MAP with larger injectors. Probably going to shoot for 10-11 psi. Any idea what injector size I should install?
Check out RC Engineering at this link:
http://www.rceng.com/
Click on Technical Notes/Sizing. Injector size is a function of expected HP, fuel pressure, forecast fuel consumption, duty cycle, and number of injectors.
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Right people, small update.
I have been real busy with work of late and as Summer is comming I decided to pull my finger out and get buying some parts.
I fitted the Evolve (E30Zone) chip which gave me another 6bhp over what it had before. It also took away the rev limiter so I decided to fit a Dastek Unichip aswell and lower the limiter to 6800 RPM as peak power was long gone by then. I am kinda expecting the peak power to be past 7000 RPM or around there so thats why I got an Evolve chip as it raised the limiter beyond this.
After speaking to Tim_S about his polly vee pulley kit he has on his car, I purchased an E36 318is pulley kit with front crank damper with matching crank sensor, alternator with matching bracket, pas pump, and water pump pulley. Also the tensioner to keep things tight.
I already have the Rotrex SC, but I have 2 sizes. One does upto 2ltr (18psi) and the other does upto 4ltr engines. I was thinking of using the smaller one as I don't want to have much more than 10-12 psi on the stock internals.
Appletree assures me the pistons are Forged in our M42's, although Tim thinks different. I have a few of these engine kicking about and am prepared to blow one up if it comes to it lol.
I will be mounting the SC where the AC compressor would normally be fitted. I will also be fitting a large custom made front mount intercooler. I will also be fitting an oil coler for both engine and SC. The intercooler will have a large surface area but will not be "fat". I will be drop kicking the viscous fan over the nearest hedge and installing a large slim electric cooling fan to the radiator. I want also to fit a larger radiator to help cooling.
I need to work out the injectors I require for a bar of boost. Not that it will get that high, but I don't want to be running 100% duty cycle either. I may also fit a raising rate with boost FPR to help things here too.
While I am there, I will be fitting a sterring rack from the E36 318is too, anyone know how much less turns this is over the E30 rack? This will make the conversion to the E36 pas pump easy as I can use the pipework too.
I also need to calculate the SC pulley size to the crank pulley size as I dont want to be over revving the SC past its max capacity. But saying this, I will be fitting a boost controller which will open and close a blow off valve which should allow me to run the SC very close to max capacity at max rpm, this will allow the SC to start boosing from much lower down the rev range, also with the boost controler, I will be able to up the boost - or lower it very easily. One thing is for sure, it won't loose boost right to the limiter ;)
The Battery is going in the boot aka M3/325i sport. There will be a reservoir for the SC special oil and a catch tank/breather where the battery went.
Anything I've missed? Any constructive comments would be greatfully recieved :)
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Good luck paul, hope evrything goes well i can not wait to see this up and running ,
Arron
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hello everybody!!! been reading things in the background but i thought id post abit now!
Ive read in a few reputable books now that the M42 does have forged pistons as standard but that it have lighted conrods NOT forged.
Also read and seen afew pics of M42 with a conrod out the side of the block even though they havent been running boost or overly tuned N/A just tryin to get top speed on the motorway *** Private runway*** Not good!
mines been runnign well with 8 psi the main problem with mine i belive is the inlet temps which are to high and ive now started to work on getting them done.
As some of you from the zone know ive got my H-beam rods no and spent today strippingthe block down to see what condition its all in.
Is there any way of checking wether somthing is forged or not??
Just looking at the conrods they look cast as there looks to be abit were they have been cut off from alarger bit of material and then machined flat.
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hey fellas! Matt, check the BM technical info for the M42, states rods are forged steel, and no mention of forged pistons. This tallies with what I thought when I pulled an m42. Pm me your email, I'll send you.
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If there is any doubt on the rods or pistons, I will get another engine built up using special pistons. But I intend on keeping standard CR although I may play around with this a little ;)
Matt, I havn't forgot your pics mate, just not home right now but will take some within the next couple of days.
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Ok mate, i for got to say that i'am running rover K-series injectors from the 1.8 16v there biage/creamy in colour and at 200bhp they were running at 80% cylce with 4bar feul pressure.
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Ok mate, i for got to say that i'am running rover K-series injectors from the 1.8 16v there biage/creamy in colour and at 200bhp they were running at 80% cylce with 4bar feul pressure.
That makes sence, I just mapped a Lotus Elise with a 1.8ltr K series Minister engine with standard K'series injectors. That was at 100% duty cycle over 6700RPM and was running a tad too lean for my personal liking at 7500-8000 RPM. That had 221BHP in the end. I am sure the FPR was a 3bar standard item though.
I'll think I need some different ones to those?
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If you find some bosch fiment ones that run 230-280 bhp drop me a line and let me know what there out of please!
I did look at VAG 20VT injectors but dave walker said when he mapped them they ran 100% cycle at 200bhp so said i should use the K-series ones to get that little bit more and still run a sensible duty cycle
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I strongly recommend the RC Engineering website as they have a great tool for calculating injector flow http://www.rceng.com (http://www.rceng.com). We're running 750's and didn't exceed the duty cycle until 27psi. At lower boost levels running about 60% duty cycle.