engine and drivetrain How much power can the rear end take?

[winstontj]

If your motor only puts out 200 at the flywheel then the standard BMW rear end will be fine. The driveshaft is EASY. I'm assuming you're going to run whatever Nissan transmission comes attached to the block you are using right? Just bolt everything up, (the rear end's bolt holes are ovals so make sure you are in the middle) bolt the driveshaft up to the rear end and the center bearing, and measure. The only way I could see you running into trouble is if you need to make the drvieshaft LONGER. You're going to have to change flanges which involves grinding out the welds and welding in a new flange. I just spent $128.58 to have my BMW driveshaft shortened, the flange changed from a 4-bolt to a 3-bolt, balanced, painted and shipped back to me. U-Joints would have been an additional $80 or somehthing but they said mine were good. So get yourself a Nissan driveshaft, cut the forward 12" off measure up and send it out. For about $150 and two weeks you can have it back in your hands ready to go.

On another note, I'm also interested in learning which SR20 motor you will be using and how much it weighs. I did a little research on the Nissan SR motor and there are many variations:

SR20Di = Nissan Primera, 116bhp @ flywheel Bore and Stroke 86mm

SR20DE = Sentra, NX2000, 200SX, Infiniti G20, Pulsar, among others, 140bhp - 160bhp built from 1990-2002 bore and stroke 86mm

SR20DET = (TURBOCHARGED) Silvia, 180SX, Pulsar, 200SX, Sentra, 205bhp 86mm bore & stroke

SR20VE = (TURBOCHARGED) 86mm bore & stroke 190bhp

SR20VET = (TURBOCHARGED) 280bhp 86mm bore ans stroke

The reason why I took the time to list all of this out is that at first glance the only thing it appears that you are gaining - or losing it weight. You are talking about the same exact capability out of a motor with TONS of fabrication and modification required. The BMW S14 motor will be more expensive but stock is 190hp at the flywheel. If you are running a non turbo SR20 motor stock you range between 116-160bhp at the flywheel. That's the same as our M10 with little to no work. You can get 180hp from a 2.2L fuel injected M10 or you can build a turbo motor and put 250-300 to the wheels.

I think you are going down a road that may not lead to where you think it does. As I said it looks like you are gaining nothing - only losing weight with the use of an alluminum block rather than an iron block. Sorry to sound so negative but as others have mentioned there is a whole array of BMW motors that are VERY bolt on, direct swaps that produce cheap good power. Why deal with the nightmare of putting a Nissan motor in? You want torque - M20, you want stock hi revving HP - M10 race built, you want the best of both - S14, then there's always the M42 16V 4-cyl. The M42 and the S14 are bolt in 150-200HP, the M20 is not so bolt in but same range. Look at BMW options before you try this transplant. The cost of machining a bellhousing / fabbing a transmission alone will over-run the cost of building a nice 175HP M10.

Just my thoughts.... Go read my early posts. You'll see I got my butt handed to me by this forum by looking into options similar to what you are looking at now. I've come full circle and realize that the easiest, cleanest, most reliable power I can get will be out of either an S14 or an M10 with forced induction.

Best of luck though!

TJW

[TMK-001]

The motor he is using is an SR20DET "Black top" out of a Nissan 180SX. The black top is probably the tuner scene's prefered version.

I think the reason why anyone would consider this is that the price of anything to do with these Nissan motors would generally be far cheaper and far more options for tuning to make serious power figures.

Like others have said, it is far easier to use BMW sources engines - but this bloke is already heavily committed to the SR20DET conversion and noone is going to sway him otherwise...

I admire your desire for individuality, but my desire for less headaches has lead me to approach my car in a "Road most travelled" fashion. (in saying that, I know of two RHD S14 powered 2002's... both running very different set ups!

Todd

[winstontj]

I remember a neighbor of mine cautioning me about putting non BMW parts in my car when I spoke of the Volvo vented brake upgrade. He cautioned about resale, keeping track of replacement parts in the future, and a whole array of problems. My car is now tracked on a giant Excel spreadsheet with parts installed, to be installed, and replacement part numbers and sources. It's going to be a lot of work and cost buckets of money to install something like that and then he better either keep it till he's old and grey because you can't sell something like that.

It's just leading up to a dissapointment that's all...

[NickVyse]

It's just leading up to a dissapointment that's all...

is that what is known as a humble opinion!?

[TMK-001]

It isn't like he is the first to do it...

I guess it is really a matter of how much you want to retain BMW or how much you want to R&D to fit a BMW.

R&D= TIME + MONEY

[-=Charley]

ooh the sr20-02! I cant wait to see this done. but i gotta admit, i was scared away by the brakes and steering box. glad to see someone tackling it. bastardizing is putting a V8 into an '02 not a lighter stronger 4 cylinder. good luck!!

[edgefinder]

2 biggest drawbacks to the M10 are weight and antique ports and combustion chamber. So how much weight will it save? Is it from a rear wheel drive car with aluminum case rear end?

[lelio]

like TMK-001 said it is the sr20det, i bought the front clip of a 180sx(very similar to an s13 silvia), ill be putting it in transmision and all so there won't be any bellhousing issues to work out. I may have to redo some of the transmision tunnel though, as the nissan bellhousing is quite a bit bigger.

I like the sr20 200hp more than the s14's 190hp because its already a turbo. that's total personal preference though. NA motors definetly have their benefits.

winstontj , your right, this car will be worth nothing to anyone except for me, i better like it

I have the sr20 and the m10 sitting on palettes next to each other right now, i keep meaning to weigh them, ill post it when i do . I weighed the whole car when i bought it (1280 lb on the front 1040 on the rear, 2320 total) . but ive taken so much else out in the process it wont really be a good indicator as far as engines go.

i still havent decided what i want to do with the rear end. I was thinking it would be perfect to put in some kind of muscle car rear end, just so i could have the trifecta: german chassis, japanese engine, american drivetrain

in reality ill put it off for a while and see how much patience and money i have left when i get to it. its good to know its an option, albeit a risky one to just use the stock one.

[winstontj]

I'm in the process of collecting and buying parts to build a hopeful 250+HP forced induction M10 motor. If BMW made an aluminum block 16V 4-cyl that was a RWD car I would own one and it would be on it's way to living under my hood. I'm in the same boat you are and that SR20 motor is highly tunable. You can put bigger pistons and a bigger crank (do you know they made a diesel version that was 2.2L & 2.3L) and do exactly what I'm doing - build a 2.3L forced induction stroker motor. Only when we are done you'll have a Nissan motor and I'll have a BMW motor.

(and yours will have 8 extra valves, probably 50+ extra HP, mine will probably have an extra 100lbs, etc...) It's a smart thing what you are doing - just too bad none of us can find a BMW version to keep things real. Just do one thing for yourself and everyone. If you're going to bring it - BRING IT. Don't do some half-ass hack job that everyone will laugh about and cut you down over. You have an opportunity to turn a lot of heads if you can pull this off in a nice, clean, professional looking package... and a LOT of people (including myself) will be jelous of what you have....

Best of luck and weigh those motors ASAP because we all want to know!

[wazzu70]

sounds like you are going about doing this right and have the proper tools at your disposal (machine shop). Even with a manual lathe and mill I have been able to make some pretty neat custom stuff! Im sure the end result of this project will be pretty cool.

[lelio]

thanks for the encouragement, and good luck with your turbo m10 (or did you mean supercharged? do people ever do that to these motors?).

mechanically I intend to take my time and do things clean efficient and strong with performance always taking first priority. but i may let down some people as far as aesthetic goes. Im not going to have an expensive paint job, im going to remove all trim, weld up the wholes and DIY flat black paint. thats just the kind of car im interested in, stripped down basic and fun to drive. with the interior im aiming for clean painted sheet metal, racing seats/harnesses, gauges and toggle switches mounted on brushed alimnum. you get the idea. a race car that you can drive to work.

maybe this weekend ill get around to weighing them, right now im all caught up in working out the steering and brakes situation.

[M20Curtis]

Hey there, I am the turbo M20-2002 idiot that has been eating diffs for a while now. I am back to a 3.64LSD which seems to hold quite well for the last 6 months now. The open diffs just can't handle the power or torque. I am at about 300bhp and 320lbft and this diff seems quite good. I am still looking/waiting to find something unbreakable so I can up the boost and got for about 400bhp. Anyone help me in that area?

-Curtis

[KFunk]

Keep her rear end lubed up good, and she can handle quite a bit!

Sorry, I can't be the only one that read the thread title that way.

[winstontj]

Nice KFunk... Real nice....

Curtis what about an ///5 rear end? or something out of a 7? They have to handle what you push out right? It can't be all that hard to fit onto the subframe. If you can convert to an M20 you could do that right? I would think the hardest part will be the diff spacing between the spindles/hub and the diff....

Have you gone down that road? Also WTF are you doing to blow out these rear ends? Are you doing brake stands? Laying strips? Drag racing? The torque shouldn't be a problem when you are moving, even if the wheels are turning slightly... so you must be going through tires and clutches too????

[M20Curtis]

I've been looking for what diff's look similar to an '02 diff and none look too easy. If I break another, I'll make something big fit that I can't destroy.

Most of the diffs break in burnouts and launches. The number one cause would be trying to shift quick or slamming a gear so I haven't done that in months, just get it in gear and when boost is built, it catches 99/100 cars on the road pretty quickly. Only one has broken under moving load and that was a VERY loud boom and lots of grip. I like wheelspin because it just makes smoke and such, no big breakage.