M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Swaps, Turbos, Buildups => Topic started by: oldtimer on October 22, 2007, 07:28:52 PM
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Just have a couple of question about force induction (turbo) so I have some basic idea about setting a system up for my 1991 318is.
I have seen several photos of other set up. One question is. Is the MAF gets eliminated? If so how is the air flow gets metered?
Do I need to change the ECU for better management?
The stock throttle body. Will it work with turbo application?
For the most part I can manufacture the exhaust manifold to meet my need to put together a system.
Which turbo is best to run with? T3 or T4.
What size tubing is best for the application?
How about EVO turbo?
There are several pictures of other members turbo. Most of them show the tubing being hooked up directly to the throttle body without the MAF in play or I did not see it in the photo. Thank you for any inputs. If I missed any other critical parts I need to consider please share them.
I consider myself “old school” meaning big piston, high lift cam, high rise intake manifold and big carbs for power. Now this days “turbo” is a house hold name now so I thought I would give it a shoot in putting together one.
Has anyone used the intake manifold from”666fabrication”? Does it come with it’s throttle body?
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Just have a couple of question about force induction (turbo) so I have some basic idea about setting a system up for my 1991 318is.
I have seen several photos of other set up. One question is. Is the MAF gets eliminated? If so how is the air flow gets metered?
Do I need to change the ECU for better management?
The stock throttle body. Will it work with turbo application?
For the most part I can manufacture the exhaust manifold to meet my need to put together a system.
Which turbo is best to run with? T3 or T4.
What size tubing is best for the application?
How about EVO turbo?
There are several pictures of other members turbo. Most of them show the tubing being hooked up directly to the throttle body without the MAF in play or I did not see it in the photo. Thank you for any inputs. If I missed any other critical parts I need to consider please share them.
I consider myself “old school” meaning big piston, high lift cam, high rise intake manifold and big carbs for power. Now this days “turbo” is a house hold name now so I thought I would give it a shoot in putting together one.
Has anyone used the intake manifold from”666fabrication”? Does it come with it’s throttle body?
most of your questions can be returned with "how much power do you want to make and how much money do you want to spend?"
the 666fabrication intake manifold- from jon volk's site"Just about any throttle body flange can be accomodated. Mustang style is standard as this will allow for many throttle bore variations."
as far as metering air, I have only used megasquirt, a DIY aftermarket ECU, that uses Manifold air pressure for fuel calculations.
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I'll try and answer some of your questions as quick as I can...
Questions 1 & 2 go together... I replacement ECU is the best way to go and allows you to eliminate the MAF by running a MAP (Manifold Air Pressure) sensor. It allows more flexibility in tuning and perhaps running other devices (water injection, boost control, etc.)
Stock TB can be used, but the shape makes it tough to plumb the system. I think it's restrictive as well.
If you can weld really well and have the tools you can fab up a manifold, but there is a fair amount of science and work in creating an equal runner length (tuned) manifold. A log is easier but much less effecient, especially with a 4 cylinder.
I'm not sure you can get enough displacement in an M42 to justify a T4 turbo.
Tubing size depends on a number of variables as well as which part of the system you're talking about. Pick up "Maximum Boost" by Corky Bell for info on manifold, intercooler, and exhaust plumbing.
Can't comment on the Evo turbo as I don't know what it is or how big.
Now that I answered your questions, here is an off the top of my head list of the decisions you'll need to make for a full turbo build. For some you can say "Keep it stock" but you still need an idea of what you just decided.
Stroke, bore, compression ratio, CAM lift & duration, valve size & spring type, rev limit, spark plugs, injector size & type, fuel pressure, fuel flow (pump), ECU, intercooler size, intake plumbing, throttle body size, oil cooler & plumbing, radiator size, exhaust manifold type, material and tubing size, exhaust pipe diameter and routing, BOV & waste gate springs, O2 sensor, instrumentation, waste gate/boost control, internal/external waste gate, turbo flange, exhaust flange, turbo size, trim, and A/R, oil return to block/pan, clutch and flywheel. PLUS all the mounting, plumbing, and routing decisions to make it all fit and work.
Then you have to find the parts and put it all together.
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Now that I answered your questions, here is an off the top of my head list of the decisions you'll need to make for a full turbo build. For some you can say "Keep it stock" but you still need an idea of what you just decided.
Stroke, bore, compression ratio, CAM lift & duration, valve size & spring type, rev limit, spark plugs, injector size & type, fuel pressure, fuel flow (pump), ECU, intercooler size, intake plumbing, throttle body size, oil cooler & plumbing, radiator size, exhaust manifold type, material and tubing size, exhaust pipe diameter and routing, BOV & waste gate springs, O2 sensor, instrumentation, waste gate/boost control, internal/external waste gate, turbo flange, exhaust flange, turbo size, trim, and A/R, oil return to block/pan, clutch and flywheel. PLUS all the mounting, plumbing, and routing decisions to make it all fit and work.
Then you have to find the parts and put it all together.
i think u just scared the crap out off him....LOL!!!
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check the forum , many turbo applications have been done , i am one of them...stock ECU with biggyback instaled , stock engine , stock intake , stock compression , 0,5 bar pressure , 200 hp
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No, I did not scared it definitely verified that I need to completely retire so I can play with this type of things. The care I want to turbo is my daily driver having been to use to driving more powerful car (Boxster S) but enjoy driving my vintage E30 I want to have the power when I am driving on the highway with a huge group of poeple who drives like an old lady. All this inputs have help I have gathered a lot of infor to determined the system and located majority of the parts. The engine is out of the car so I am able to simulated the exhaust for fabrication. Oh yeah I have managed to acquire a "mandrel" tube bender and a miller syncro 250 to fabricate most of the tubing. For now I am shooting for a stock engine to be turbo when I can spend more time in addressing all of the parameters mentioned I will do that to my other E30 which is prep for a larger engine (V-8) my son's idea.
The final HP I am shooting for is doubling the stock HP. So I guess around mid to upper 200's.
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with a set of forged pistons , new head flange bigger to drop compression to 9:1 you can go 1,2 - 1,5 bar of pressure , and go about 340 - 400 hp..
so if you have the engine out , it is easy to change these things..
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definitly drop compresion, im gonna use stock internals with new pistons just to run 8psi for DD, im still debating the engine management, can the stock ecu be used for 8psi?
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One of the biggest issues with the stock ECU is that there is no knock control. You can try and tune it out but you're leaving HP on the table and have no protection against bad gas or higher ambient tems that can cause problems. I'm not that familiar with the piggyback systems and how they operate. The ideal setup is something that integrates a MAP sensor in place of the MAF and can be tuned for your specific injectors, fuel pressure, O2 sensor, and desired ignition at a specific RPM given other variables like engine temp, intake temp, throttle position, and amount of boost.
The problem with an aftermarket ECU (aside from cost), especially one with a MAP sensor is that it won't pass inspection in most states.
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Hi,
I've just collected all the info needed to build my M42 turbo project.
I would say - consider VEMS / http://www.vems.hu / it is similar to Megasquirt and has knock controll and even EGT /exhaust gas temperature/
To double the power - I'd say That You have to do following:
Change the injectors or add second set of them into the system :-)
Go T3 rather than T4 /as said before too less exhaust gases to run it early enough/ T3/T4 is capable of doing 260-280 HP in this car /as it is shown in some cases for example on http://www.e30tech.com / Anyway I would definately recommend Holset HX 35 from scania truck.
Lower Your C/R, but You don't really need a new set of forged pistons. Stock should do the job, but You have to lathe them to lower C/R. The line on the picture shows how much to lathe the piston :
http://www.e30.kamieniwnetrze.pl/turbo_m42/piston.jpg
I didn't measure it but it should give You about 9.5 : 1 C/R with stock headgasket. Replace it with 1mm headgasket and You are close to 9:1 :-) This is really enough, but the intercooler needs to be really efficient and You should have knock control. The higher the C/R the more responsible is the engine, but You have to avoid detonation at first.
Stock internals /crank, rods, even cams/ will do the job pretty well, but You have to keep in mind that You really need good intercooling system and low restricting exhaust pipes. On stock cams M42 is capable of doing 300HP with 1,5 bar of boost.
Of corse to keep it safe, You have to tune the turbine to get You the power near the red line, because the torque will not be too large if done so. On the other hand You probably could go 300HP's with 3000 rpm's but the torque would definately hurt Your stock internals.
throttle, intake manifold - keep theese stock - they will do the job for 300Hp's for sure
I'm worried just about the inspections... The car has to be street legal... So You will have to recalibrate it to pass emission tests...
But it is generally possible to manage Your 4 injectors with 2 different maps, one for economy and passing tests and the other for the performance.
Corky Bell's book "maximum boost" is really nice, but I would strongly recommend Jeff Hartman's "How to tune and modify engine management systems" it gives You more specific info :-)
GOOD LUCK!
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I would definetly not recommend to lathe the original pistons, a couple of M42 turbos here in Sweden has done just that and all have failed their pistons in the area between the top of the piston and the first piston ring.
I believe they were running 1-1.3 bar boost and used a standalone ECU tuned the proper way. I would rather go with forged pistons or a Cometic MLS 3mm gasket.
One alternative could be using pistons from another engine with the same bore, I'm using pistons from a M54B30 engine which has got ~3mm lower compression height than M42 but with a flat top instead of a negative dome. They will lower the CR to about 8.2:1. A bit low for my taste but they'll have to do as I'm only building this engine to test if I like the concept of M42 turbo and circuit racing. I would not recommend this if you're going 1+ bar.
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I can tell you from my personal experience that a T3 would be too big for a stock displacement and you won't get more than a few pounds of boost at 3K. You might want to learn to read compressor maps and there are some guys over at Bimmerforums that have put together some good tools. My guess is a GT2860 would be a good choice for stock internals, would handle 10-12psi nicely, and put down about 230 RWHP. The VE of the stock heads falls off after about 5K RPM so torque will fall but HP will continue to build. I would not worry about it as a daily driver but we definitely need a major head rework for the race car.
For a daily driver, it's not about the max power but about the range. In this case, I would be willing to trade and use a smaller turbo for a more responsive and broader power curve.
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I'm hoping to put down just over 200 at the wheels myself. Now if you want reliability with umph ask yourself if you want topend or low end power. All this could be set by good gearing.
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One thing to keep in mind that a turbo setup should product more torque than HP. If you want that feeling of "umph" when you get on the gas, it's torque. Worry less about the peak HP and more about a broad torque curve.
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My idea was to go with high end power, which is much safer to the pistons and letting the engine breath well /by constructing low restricting exhaust system and digging the head little bit/. Combined with high octane gasoline and very efficient intercooler should let You 300HP's near the red line still not damaging the pistons lathed to give C/R about 9:1. Of corse latheing stock pistons is not really best way of lowering C/R but it should be durable enough with 0,8 bars or something about 1 bar... But it must be near 5000 rpm's, because in the other way heat and pressure will destroy theese stock - not forged pistons. If You need high drivability with whole rpm's there are better ways of achieving this - rob You know the work well ;-) But for demonstrating the power from time to time, high end power system should work nicely to compete potentially stronger cars.
I hope it will work well ;-) The idea of latheing stock pistons came from... Sweden :-) Mattias Sandgren has put this photo somewhere on the e30tech forum while discussing low cost turbo setup.
For acceleration car, You can have bigger turbocharger despite it will not even start producing boost at 3000rpm's... The better as I think, because You still have economical car below the powerband ;-)
But think it once more. Your engine will work just in the way that You will design it.. And it is not said that it should give You flat torque through the whole rpm's to be nice and driveable... It depends on what You really need.
Me personally like the most idea of the high end high reving turboed engine, but it is not the engine for comfortable everyday use.
strypt:
Do You know other info about theese damaged piston engines setup?
I mean what turbochargers they used and if they were low or high end power?
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Latheing pistons works pretty well in some engines like M20/M30 where they have a dome to remove but the M42 has proven not good for this. Or maybe these guys where pushing it too hard.
I don't have a whole lot of information on these M42 turbos but I know that one was running a MHI turbo (TD04HL-16T) and another one had some kind of Precision turbo, might have been a SC44 but I'm not sure. I'll try and see if I can find some photos.
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thank You for the info about theese turbochargers, it seems that they used traditionally designed turbo setup. This means that engine is comparably strong through wide range of rpm's. Big turbo idea leaves engine nearly stock up till the powerband and then 300rpm's step and You are in another world... I mean that You have 80HP's at 4000 and You have above 300 at 4500rpm's... /for example/
I like my idea far more -> Look it this way:
We understand HP's by torque multiplied by rpm's and something else. this means, that You double the power by doubling the torque /which generally affects piston pressure/ or doubling the engine speed /which is not safe because it would be too high reving for the inside parts.
But: look what will happen when we would put highest torque present in stock engine for example 2000 rpm's higher...
with stock setup and internals we would make much more power not affecting internals at all /I mean that we wouldn't put any more piston pressure but we would be able to get MUCH more HP's.../
Generally it is quite achievable when You put big turbo into this setup:
look what happens:
at stock peak torque turbine is not producing boost, so we have "stock" engine curves.
above stock peak torque our big turbo starts producing boost, what affects torque and risens it up. But in stock engine the torque was falling down, so we want to raise it just to the "stock engine peak torque" level...
And going up with rpm's, we keep the pressure regulator to give us "just" the amount of air needed to keep the torque at this level up to the red line...
Look at the torque/power graph for the M42 engine. I don't see it now, but generally the peak torque is 175Nm at 4300. At peak power we have just about 110Nm but at 6000 and this gives us 136 HP's. If we could raise the torque at this moment to the 175Nm level, the power output would raise about 1,59 times which gives us 216 Hp's... Still having completely stock pressure, torque or any inside strenghts. Of corse rpm's raise, engine wear is bigger, but the inside strenghts are nearly on the same level - not affecting internals more than while reving 4300 under full load.
Immagine 30% safe area. This means that stock engine can keep up to 130% of stock peak torque /175Nm*1,3=227,5Nm /, and this gives us 280Hp's at 6000rpm's
Heh we have just 30% more torque... It's not a black magic for a turbocharger ;-) But it has to be done near the red line...
Generally we've just build 280Hp's M42 with stock internals and it is still quite safe for them. Isn't it what You wanted to achieve oldboy? And the taste is that below the powerband You still have stock 1,8 ltr engine burning about 8-9 ltr per 100km !!!!!
BUT EVERYONE : I'm not the expert, this is my idea of building turboed M42 which will be done next winter ;-) I'm still collecting info and money for the project...
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Abrax,
Have you built one or seen of these motors or is it still in the theory?
One challenge is that large turbos are ineffecient and generate a lot of extra heat outside of their "sweet spot" and I suspect an engine like you're describing would be challenging to drive and not much practical use. If you want to keep the effecient 1.8L motor, it's still in there just don't stomp on the gas!
The proper sized turbo should give little to no lag at all and you should be able to moderate boost via the throttle.
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right, right... I believe it will work.... But it's not the common turbo setup. I've seen some from swedish sites build similarly, but mainly they were 8V 4cyl volvo engines...
I wonder to build one and that's alll :-) I don't feel the lag will break the fun. It scholdn't matter while You are sprinting quarter mile....
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I wonder to build one and that's alll :-) I don't feel the lag will break the fun. It scholdn't matter while You are sprinting quarter mile....
Agreed that the adventure of building one can be half the fun, but building a 1/4 mile engine is VERY different from a road race car or street machine. GL with the build. I'd love to see what you come up with.
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I found two pics of the installation, none on the broken pistons though. This is the one with the MHI (Mitsubishi) turbo. He was running 1.3 bar when the first piston failed, but all pistons had cracks in the same area. He then lower the boost to 1-1.1 bar but they failed again. He's now using forged pistons ;)
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right, right... I believe it will work.... But it's not the common turbo setup. I've seen some from swedish sites build similarly, but mainly they were 8V 4cyl volvo engines
If I'm not mistaken those Volvo engines HAD forged pistons stock. Alot of the older Volvos did, considering they were not a large company as they are now backed by Ford. At that time they had to out source for some of their products.
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If I try to compare this MHI turbo to HX35 it is hmm... more than 2 times smaller...
http://www.holset.co.uk/files/2_1_1_3-Holset%20HX35.php
:-)
I believe that this MHI ha to make power in low end.... So it was made by strongly increasing torque, which was tooo much for a stock piston...
I will aim somewhere into 6700 or 7200 with lightened inner parts, and at first I will try with stock pistons.
I think they will stand it pretty well. Byt we will see.
Simply You will notice my turbo thread when I will start my work :-)
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They are small yes (physically) and will produce boost at low rpm's but they are still capable of ~300 hp (smallest one) to about 360-370 hp (biggest one with 46 mm inducer, 58 mm exducer). I believe the smallest HX35 also has 46 mm inducer, dunno about exducer, but still one shouldn't compare only outer dimensions on turbos. One good thing about these MHI's, except for the size and great spool, ;) is the fact that they come with a 360 degree bearing from factory which makes them very reliable and endurable at higher boost levels.
But yes you are correct, they are no alternative for your engine :)
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I meant that if You are building turbocharged M42 with turbine producing boost down low, there is no other possibility to change pistons for the forged ones, because stock won't handle that great strenghts...
There is a possibility to create serious power w/o changing pistons, but You have to go big turbocharger, don't care about lag and rev it to see the power...
Anyway, if You are over 4000 the lag matters just till You spool the turbine for the first time, after this You have it creating enough boost to change for the next gear... and You have it just that long, that You are reving high.
I feel it that way:
In normal driving You don't really rev Your engine. While city - city driving You don't really need serious power to overtake or normally accelerate. But if You want to race somebody or just disappear, You have to reduce 1 - 2 gears, rev Your engine high and off You go!!!
Consider that while normal driving You have just "stock appearing engine" with all it's benefits like high milleage or nice torque curve. Everything changes when You pass this magic 4000 to let Your turbine produce boost...
While having small turbo, You have much less "agressive" engine but You can't expect that high milleage reving 3000 because the engine is already under the boost....
I know, You will say that it is not like that, because You don't have to open the throttle that much, because You have stronger engine... But the truth is that the engine with smaller turbine will be definately less economic at 3000rpm.
Don't feel it? -> check it...
strypt:
I don't say that the turbines are not capable of making serious powers... i just wanted to say that this size of the turbo will make your exhaust filled very soon... So on one hand You make the engine to be strong and on the other side You put the plug in the exhaust just stopping Your engine from creating power near the red line...
From my point of view the optimal situation is when critical area of a turbo is not smaller than 14ccm. This lets M42 breath well... But the difficulty is that in this case A/R of the turbine is not really helping to spool it in the low end...
You guys place the ability to spool quickly much more important than me... But You probably won't get that kind of power at the high end...
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I like what I read at least I think I got the big picture. With stock parts in this case pistons I have to select a bigger turbo so the stock piston will handle the boost but the power from the boost will not come until I rev up the engine around 4k. which is fine with me it is around that rpm range anyway when I would like the power for overtaking and just get some distance from people who likes to hang out together on the highway. I drove a friend 1988 911 turbo when I did in order to feel that boost from the turbo one has to down shift and get the engine around 4k. So If that is the case getting a bigger turbo so the stock parts will survive the boost. What size are we talking? T3 or t4. I am not all that concern about the lag or waiting around 4k to get the power. Around town being daily driving I rarely rev up beyond 4k to up shift.
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T4 is still going to be too big. I have a GT30XX on a 1.9+L race built motor and I'm getting some boost @3K and full by 4.
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For precise info about Holset sizes ask Ixer on http://www.e30tech.com/forum/ - he is my "Holset guru" ;-)
I would calculate airflow of the stock M42 at 4000 rpm and compare it with efficient modern diesel truck turbocharger /like holset HX for example/.
You will find that truck diesel's produce power near 1,5k rpm's with engines like 6 - 8 ltrs... Somewhere here rests the answer. If the 6 ltr diesel truck produces boost when their airflow reaches X and this X means airflow of the M42 at 4000 - You got it this turbocharger will start to produce boost with Your engine too. Of corse diesel's have much higher exhaust pressures, but this should only mean that our gasoline engine will spool the turbine little slower.
So it may be right that T4 beeing smaller than a HX35 will be too big, and HX beeing even bigger will be ok. It depends on innertial construction of a turbine...
Holset is big, right, but very efficient and it is not really said that it will be too big...
find the old 1602 BMW on http://www.savarturbo.se -> http://www.savarturbo.se/?sida=content/bilarna.php&bil=peter Check the size of the turbine it is equipped with and has 2ltr's of displacement...
It will just produce power really high there.
I don't feel it would be good to leave just 500rpm's while using turbo which will start to create boost just over 6000...
But aim at 4000 rpm and You will have nice bahaving 2k powerband quartermile engine
I didn't also said that stock pistons will definately take this...
I said that If You plan to go turbocharged and don't want to spend fortune on it, there is possibility to stay with stock pistons, but You have to go big turbo. And keep in mind, that You definately shouldn't pass stock peak torque too much ;-) Also install big, big intercooler and knock detection!!!
I recommend http://www.vems.hu , http://www.holset.co.uk
also read more at http://www.e30tech.com
GOOD LUCK -)