Help! M20B27 Performance Upgrades?

[squidrope]

^as much as i love the 2.7i and variants, i think he wants to keep it almost all ETA as far as engine internals go so that he can tell people hes beating them in an ETA.

This

[E30 Wagen]

So, are you against port matching with a 325i intake manifold?

I wouldn't be afraid to go to the extreme with lightening the conrods and pistons (and balancing).

[squidrope]

I'd like to keep it as "e" as possible. Teammates are also not wanting to spend much $. So it's no to the "I" stuff.

Hadn't thought of lightening the rods and pistons. Can you point me in the direction of where to find pics of lightened rods and pistons.

I'm assuming the crank counterweights would need to be lightened as well?

[E30 Wagen]

Sorry I've never seen pictures of m20 parts after lightening, but this guy has some videos of various rods being machined down:

https://www.youtube.com/watch?v=bThiGTY0-wA

https://www.youtube.com/watch?v=IbaOAVJiSpg

https://www.youtube.com/watch?v=z1693x0Rh9s

https://www.youtube.com/watch?v=3VjVV2a-_oU

Edit: not sure that tapering the top of the rod is a good idea..

Pistons being lightened:

https://www.youtube.com/watch?v=xZnWMGXsc-U

I'm not sure about lightening the crank; I would just check the balance and go from there. Would be interesting to see how much total mass could be shaved off.

[squidrope]

Thanks for the links. I should have been more specific, I thought someone might have pics of m20b27 rods or pistons modified. As I understand it each part on different cars have different strengths and weaknesses. What might work on a Honda won't work on a Subaru etc.

I'll do some digging to see if there is anything out there addressing the pistons and rods that I'll be moding.

Just guessing but that the mod of the top of the rod makes sense to me. Most force is on the power stroke which impacts the lower potion of the top. The top of the top keeps the piston from flying into the valves but shouldn't need to be as robust as the lower portion???

Wouldn't the crank counterweights need to be adjusted because they "counterweight" the lightened piston/rod assembly?

[Chuck Baader]

A couple of observation from my years of racing an eta motor. Install "i" vibration damper and go with a MegaSquirt PNP. (need an "i" engine harness, too.) Never run without the damper as it will kill the crank pulley key.

Headers...1.5" x 36" primary into two collectors, one 2.5" x 9.25" and the other 2.5" x 18.5" into a merge collector with a 3" outlet. Muffle as you wish from that point, but be aware of back pressure.

A good valve job with the above mods will yield in excess of 150 wheel hp and 185 wheel torque. Red line, with stock valve springs, needs to be 5600! If you switch to "i" springs, you can turn to 6500!!

3.91 gear is excellent for the eta motor. Gives a 122mph-ish top speed (5600rpm red line) but is buzzy for the street.

[darvo]

^^^^ Nice, Couldn't the head also be modded to run an I Cam?

[E30-325iS]

Pics of lightened rods, but never going to get as light as an after market rod.
http://www.e30tech.com/forum/showthread.php?t=80476

[squidrope]

Thanks to all for the suggestions and keep them coming.

My "team" exploded and I'm left building a new car.

Here's what's in the works:
More lightening than first car. Aiming for 1925 lbs. or less, and better f/r balance
Lightened flywheel
25% reduced water pump rpm
Smaller/lighter BMW motorcycle altenator (saves 5 lbs. and less work for motor)
Lightened Harmonic balancer (pulley machined off and smaller Alum pulley integrated)
AC/PS/ABS removed
Fixed drivers seat in rear seat footwell with movable pedals (better f/r bal. quicker driver changes, less weight)
Lightened rods, pistons, crank
Crank scraper
e-bay header
forced/cold air induction (thru headlight?)
Turner ETA chip
Vert (cage will be easier to fab and will more than compensate for lacking roof stiffness)
Clean up and balance ports
Adjust LSD ramp angles


Wish me luck, and I welcome any other suggestions to help this ETA beat up on the i's and 2.7i's

[digger]

The most restrictive part of engine is the inlet valve and port in this area up and down street about 1".