Author Topic: Buildup: My quest for NA 180 hp (Read 84819 times)

Boyracer · « **on:** June 12, 2007, 04:18:24 PM »

Finally on sunday I bagged some spare parts from german ebay:

E36 M42 Cylinderhead
E36 M42 Valves (6 mm stem)
E36 M42 Valve springs
E36 M42 Hydro lifters
E36 M42 Camshafts + camshaft carriers
E36 M42 Camshaft sprockets
E36 M42 Pistons
E36 M42 Con rods + bearings
E36 M42 Valve cover

Let's hope cylinderhead is 100% ok as seller claimed it to be. All for a 127€ + shipping. This means I can start building a performance cylinderhead while keeping my 318is in daily use. :cool:

GOALS

I have set 3 power goals for the project, 1 is the easiest (and minimum) and 3 is hardest:

1. 180 hp (100 hp / liter)
2. 192 hp (same as 2.5 liter M50)
3. 200 hp (1.8 liter Integra Type-R)

Also the engine must stay emission legal and work should cost next to nothing. Oh, and no forced induction :eek:

Is the goal achieveable? Mild Shrick cams + Custom ECU gives out around 165 hp on otherwise stock M42 without revving to really silly numbers. Mild porting of intake and valve + valve seat job can give upto 10% increase in good case. Combine that to slight bumb on rev limiter and you are already at 180 hp. After that it gets more challenging...

THE PLAN

Basically the plan is to keep the bottom end quite stock while squeezing everything out from cylinderhead while initially retaining stock intake and exhaust manifold. Exhaust and cat might be changed to lighter and more freely flowing 2.5" custom unit.

Cylinderhead

I try to get the cylinderhead to perform reliably atleast upto 7500 rpm altough I'm quite hopeful that even 8000 RPM is possible with lighter hydro lifters and bit stiffer valve springs. There are equations for calculating effects of these changes, I will write more about them later on.

Hydro lifters from VW. They are some 20 gr lighter / unit. This reduced mass (10% of valve+spring+valve plate+lifter combination) alone allows rev limiter to be safely raised 6800 -> 7200.

Valve springs from Dbilas (only 130€ + shipping!). Not sure how much stiffer they are than stock but since they can be used with camshafts with over 300 degree duration they must be quite a bit heftier. Few examples:

10% stiffer - rev limiter 7200 -> 7600
15% stiffer - rev limiter 7200 -> 7800
20% stiffer - rev limiter 7200 -> 8050 Partytime!!!1!

I'm hopeful that Dbilas can deliver info about stiffness, if not I will have them measured to be 100% sure.

Valves will be stock but with backcut to reduce weight and improve flow on small camshaft lifts. If possible, I will also have the part of valve stems that is in the intake port to be thinned 6 mm -> 5 mm. This slightly improves flow and again decreases weight

Valve seats will stay stock but they will be ground to 3 angles to improve flow. Intake seats will be also increased in diameter and then blended to intake port for better flow.

Valve guides. Not sure what to do with these. It's possible to ground then completely down to intake port wall or replace them with race guides that are bit thinner.

Intake ports. Bit of smoothing and making sure cylinderhead and intake runners match without any steps etc.

Compression. I think I will remove 0,5-1 mm from cylinderhead, that will increase compression from 10.5 -> 11 to 11.5. That is around 2-3% increase in torque (and hence power). This is a cheap operation, only some 20-30€ so money very well spent compared to power gain. Running with 98 octane (not sure what that is in US) should not cause knock and anyway knock sensors on E36 will be good insurance

Camshafts

Camshafts will be regrinds to keep the costs down, I think 270 degrees and 10.5 mm lift is the upper limit. This should keep valve overlap and hence emissions on check.

Intake

Intake will stay stock, maybe slightly enlarged TB because I have one stock unit coming and I might as well try to modify it. Remember that Metric Mechanics got 210 hp trough stock TB!

I have been thinking building completely new intake runners and plenum if stock system is too restrictive on high revs. This would most certainly mean loss of low rev torque.

Injectors

New injectors needs to be around 300 cc / min. It's better to have just enough flow capacity than too much. Too large capacity means problems on idle when ECU cannot control the injection time accurately enough leading to high emissions.

ECU and sensors

Stock ECU with custom made chip on local dyno. Stock unit should be ok to revs I plan to use. Aftermarket units can cost the same amount as everything else on this project so I'll pass it this time. It would be the ideal solution but I think power gain (more RPM bins, sequential injection, two injector banks etc.) is only few % compared to well programmed stock ECU. Megasquirt is tempting but I think there is some issues with ignition?

I initially thought building a MAF adapter but it seems that it is not worth the effort really so VAF will stay on for now. I have just ordered development tools for Atmel AVR microcontrollers and I am planning of designing Alpha N unit that disposes need for VAF or MAF, it basically pretends being a stock VAF towards ECU but without any airflow restriction. More on that later

Powertrain

Flywheel will be M40 unit lightened by few kg's (9.9 -> 7). This is very important, I think M42 with dual mass flywheel has the most ridiculous power/flywheel+clutch mass ratio of all engines BMW made at the beginning of 90's!

Stock 3.45 open diff, might be changed to 3.45 25% LSD. Otherwise some grip problems might appear on track

kowalski · « **Reply #1 on:** June 12, 2007, 05:36:13 PM »

interesting plan. I would love to hear more about it as i'm starting my build in T minus 17 days. (i arrive home from austria) and i've got a spare engine, 2 m47 cranks, an m44 crank, s50 pistons, and a whole lot more to play around with. I would love to squeeze as much out of this thing as possible while keeping it reliable. what are you going to do for engine management? I'm looking at the haltech systems...

dino245 · « **Reply #2 on:** June 12, 2007, 09:38:45 PM »

do the haltech, i can help with the set up and it is well worth it.

AL GReeNeRy · « **Reply #3 on:** June 13, 2007, 02:47:49 AM »

these goals are very reasonable and are actually what i hope to accomplish with my m42 as well. other than the option of the DASC, i wanted to reach the 200hp as mark as well. your setup sounds similar to what i would be running. ill do a quick run down.

engine
stock bottom end
rebuilt head with cams and proper valvetrain
completely rebuilt timing equipment
a maf setup with MS or some sort of tuning

drivetrain
8lb. m20 ltwt flywheel
new stock m20 clutch if not a stage 1
med. case 4.10 LSD
z4 3.0 ssk
uuc dssr

exhaust
custom 2.5" from centerpiece back (after 2-1)
electronic exhaust cutout before cat which will be replaced with a resonator

i believe our best bet would be tuning. bmws are known for being well underrated. if you can unleash its true potential by fine tuning the computer, 200hp is easily achievable.

if the bottom end is tinkered with, the whole process will be much easier.

kowalski · « **Reply #4 on:** June 13, 2007, 05:58:35 AM »

what do you all think of metrics "pulse intake manifold" I was doing some reading on it and it looks very feasible, and i can't imagine it being that hard to duplicate... for a 15% tq gain it would be really nice to have.

What are the specs of the head you plan to build greeny?

Boyracer · « **Reply #5 on:** June 13, 2007, 07:15:06 AM »

MM pulse reflection chambers are nice idea and I see no reason why they could not work. It's easy to see that air reflected from backside of closing valve would rather go straight to reflection pipe instead of changing direction and going back all the way to intake plenum.

Should be quite simple to implement as DIY, few big holes to intake runners and then weld some aluminun tube there with other end capped off

Too bad it will not work with E36 M42 I think

kowalski · « **Reply #6 on:** June 13, 2007, 08:00:12 AM »

Quote from: Boyracer;27657

MM pulse reflection chambers are nice idea and I see no reason why they could not work. It's easy to see that air reflected from backside of closing valve would rather go straight to reflection pipe instead of changing direction and going back all the way to intake plenum.

Should be quite simple to implement as DIY, few big holes to intake runners and then weld some aluminun tube there with other end capped off

Too bad it will not work with E36 M42 I think

just get an e30 m42 intake manifold. bolts right up and they're cheap.

Boyracer · « **Reply #7 on:** June 13, 2007, 09:22:25 AM »

Quote from: kowalski;27658

just get an e30 m42 intake manifold. bolts right up and they're cheap.

E30 intake manifold will not fit E36, the angle of engine seems to be different so the manifold will be higher and will stop hood from closing...

I have been thinking using lower part of E30 intake (runners) and constucting custom intake plenum from scratch (with M50 2.5 liter TB) on top of that. But I will start with E36 stock intake

bmwman91 · « **Reply #8 on:** June 13, 2007, 01:50:04 PM »

I did a microcontroller-based MAF conversion from the VAF. It was simple since the systems directly measure incoming air flow. Of course, not 1 kilowatt (not even a fraction of one) was netted doing this, but driveability improved.

I have thought about going Alpha-N, or at least speed-density. Unfortunately, this is completely reliant on the volumetric efficiency of the motor and has to be re-tuned every time you make a physical change to anything in the intake system.

My recommendation would be to convert to a MAF. Check out PIC microcontrollers...you can do a MAF conversion with an 8-pin PIC that has a ton of built in options (PWM, capture/compare module, 4 ADC channels, internal 1-8MHz adjustable clock, 2 8 bit timers, 1 16 bit timer, etc). PIC12F683 was the one.

Anyway, I look forward to seeing how this goes for you. For the time being, the stock AFM should be more than adequate! Good luck!

Boyracer · « **Reply #9 on:** June 14, 2007, 10:39:18 AM »

Hi bmwman! I read about your experiences on MAF conversion, interesting stuff and great service to community

I do have E34 540i MAF already as I was planning to perform MAF conversion so it is not out of question. I am little worried about strong intake pulses with reground cams that can feck up the measurement.

Retuning Alpha N after every change gets tiresome and expensive too. So I am studying about possibility of self learning unit. It would intercept lambda signal before it goes to ECU (ECU would be fed simulated lambda signal to fool it) and based on intercepted lambda value Alpha N box could "learn" the VE values for different RMP/TPS combinations. Quite a lot of variables and questions at this phase, I would appreciate if you can help out in this

Frankie · « **Reply #10 on:** June 17, 2007, 12:38:57 AM »

Hello J.

Don't touch the exhaust manifold yet. Just do the engine work first then the exhaust since it truly flows quit well as this dynochart will tell. You can see that the max torque is too near of max HP, which just means that exhaust manifold flows too much making the car not the respond to throttle not so good. The torque band is little bit too narrow. To fix this I should make 5 step exhaus manifold, meaning that the manifold starts narrower and widens up in five steps.

So, the exhaut of a e30 m2 atleast is not a problem. However, I have a cat-back which little bit increases the "problem".

Dynochart http://www.m42club.com/forums/showthread.php?t=2888

Boyracer · « **Reply #11 on:** June 18, 2007, 05:29:26 AM »

Too bad I missed the dynoday, I was really keen to have baseline before any modifications

Exhaust manifold will most propable stay stock forever, difficult to make a new one and stock unit is more than adequate...

I will most propably make complete custom exhaust. So everything after exhaust manifold collector will be new. I think 2 1/4" is the best diameter for exhaust but might have to go as large as 2 1/2" because of larger selection of mufflers and resonators. That might hurt bottom end torque but help on high revs. Also, you can always make larger diameter smaller (restrictor plate) but you cannot make smaller diameter larger

When I measured it stock E36 exhaust was around 2 1/4" between exhaust manifold and resonator, after that is went down to 2" until muffler.

Interesting thing was that there was clear purpose made dent on 2" part that made the effective diameter even smaller! Not sure if it was because of backpressure etc or to fit the pipe better under the suspension arms.

That follows the logic that says you should made the bit after cat/resonator smaller. That is to preserve the velocity of gas and to help cylinder scavenging. When the gas cools down in the exhaust pipe it loses volume and hence velocity. You can prevent this by making the cooler end of pipe smaller

Hmmm... After writing that I think this could be very good (but bit complex)solution:

Exhaust manifold collector
2 1/2" pipe
free flow catalysator
2 1/4" pipe
resonator
2" pipe
muffler (with 2" output pipe)

That would allow the gases to cool down gradually while maintaining it's velocity. The last section is same diameter as stock exhaust but without the dent so it would still flow bit bettern than stock. And stock cat, resonator and muffler seems to be the biggest restrictions and they will be get rid of.

Boyracer · « **Reply #12 on:** June 21, 2007, 12:40:30 PM »

Yay! Parts arrived today and they seem to be in good condition (to my untrained eye). And head has single valve springs so that is indication that it is indeed 6 mm valve head (I had no possibility to measure the stems yet)

After next week I will tear the head to parts and clean it. Then it's off to machining shop. I will post full list of modifications later :cool:

Massimo · « **Reply #13 on:** June 21, 2007, 07:32:46 PM »

I woudn't grind the valve guides back. deffernetly go for some after market ones. That is one thing you do not want to get wrong. A bent valve can do a lot of damage.

Boyracer · « **Reply #14 on:** June 22, 2007, 02:21:20 AM »

I tend to agree after bit of reading. It's cheap ghetto tuning way to increase flow but shortened guides will wear out quickly and start leaking oil. Might as well cough up the extra �� and do it properly first time