its an M30B34
and the comp is 8.0:1
... and its NA

i dont see any high comp pistons for these motors, tops ive seen is in the 9's
why is that?

hondas run 11.2+ fine?

Find some piano top pistons from an m90 L block (or the whole block). I actually had one of these engines that had a bad valve. I sold the head and junked the rest. I did save one piston because I thought it looked cool. Ignorance!!! Mine was an 80 euro e23. I was/am so ignorant I still don't know what it was. I didn't have any paper work and it didn't have any designations anywhere on it. I only bought the car because I needed the blower motor and the whole car was $200.

m90? whats that?
tried looking for it on VAC but didnt see anything

but do you know why the comp is so low on these motors?

Because they were turbo'd in the 745i? :cool

m90? whats that?
tried looking for it on VAC but didnt see anything

but do you know why the comp is so low on these motors?

Emissions. Back in the day, a high CR meant a high NOx content. (still does, but the cats help to minimize this, along with an EGR)

On pump gas, to compensate for the vagaries of both temperature and gas quality, I wouldn't go above 9.5:1. The main reason for this is because the M30 never got knock sensors. Much better to be safe and get ~5 less hp than to get those 5hp and end up stranded on the side of the road, no?

If it had knock sensors, then 10 to 10.5:1 would be perfectly fine.

The M90 is a derivative of the M88, the engine in the M1. It uses a block with the same bore and stroke pattern, with a regular SOHC head. No, the S38 or M88 heads will not bolt bolt up. The M30 and S38 blocks are different.

The advantage of the M90 is that it is oversquare, giving it excellent responsiveness and a wide torque curve. It is also much easier to stroke out to 3.8L or so, as no block machining is required.

23.6:1 :d

ooo okay
that would only get me 5 hp? lol

i think ill keep the same engine and pistons if its only a 5hp increase

ooo okay
that would only get me 5 hp? lol

i think ill keep the same engine and pistons if its only a 5hp increase

I think you read it wrong. The 5 horsepower was the difference between the unsafely high compression pistons and the safely high compression pistons.

I think you read it wrong. The 5 horsepower was the difference between the unsafely high compression pistons and the safely high compression pistons.

Exactly.

Bumping the CR from 8 to ~9:1 will net you perhaps 10rwhp. Valves are good for another 10 or so up top. Most B35s lay out ~170-180rwhp. B34s lay out ~160 rwhp.

So, it is the cost of a set of custom pistons (which is cheaper than getting OEM pistons) for ~10-20 rwhp. Plus, then you have to get a tune made. Probably at least a 2k endeavour if you did everything yourself.

The M30 is not a SBC, a modular Ford, or a 442. Those engines are hampered by lousy induction, exhaust, and fueling systems from the factory, which is why replacing them usually gives such good gains. (Ex: SBC + headers, intake, throttle, and a Holley Avenger (properly jetted, of course) will lay out 350+ all day long.) The M30 has all those systems tuned pretty darn well from the factory, which is why doing the same mods will only get you perhaps 5-10 rwhp.

If you want to go fast, take a driving class. Fixing what is behind the wheel will work far better than trying to make the car faster.

If you want to go fast, take a driving class. Fixing what is behind the wheel will work far better than trying to make the car faster.

Ditto.

You (OP) have several posts floating around and all of them have to do with improving the performance of a 20 year-old car. There is no problem with this except that you need to recognize that you have...a 20 year-old car.

The only real way to gain significant improvement in E23 HP is via FI. Yes, a chip, proper intake, and exahust will help, but you have inherent limitations with your car...

Note that I used to have an E28 535i (same engine as yours) and I modded the hell out of it (no FI, though) and had a blast. I didn't focus only on HP, though, and made a full suspension change, front brakes, SS kit (it was a 5-speed), lights, body, etc.

And, as mentioned above, improving the driver is a great place to start.

Have fun.

http://www.turbochargingdynamics.com/product-39-6-14-e32_735i_Stage_1.php

http://www.turbochargingdynamics.com/product-40-6-14-e32_735i_Stage_2.php

That would be fun :devillook

DO IT!!

http://www.bmwe34.net/E34main/Other/Racing/Turbo.htm

yea lol
but i mean, its a 3.5L
and only churning out 160-180bhp?
makes me mad knowing my friends integra is a 1.8 and makes 195 crank

i think it handles well, especially for a 4700lb boat at that

i just dont have that oomph! i need
ill be trying to get to 35 and it feels like its taking forever, and im pressing the pedal down a good inch to an inch and a half

and on my moms honda, i let my foot barely sit on the pedal, and it leaps to 35?
idk maybe its just me

hahaha i wish i could afford a TCD kit
they are clean

but i need to save my money for my project car in the summer

EG6 hatchback, K20A2 (type s) motor swap, intake, exhaust, K-PRO, and a good tune
and a bunch of other this and thats for the car

i think it handles well, especially for a 4700lb boat at that

Uh, the E38 weighs about 4,250...Not sure what an E23 weighs, but it's certainly less than mine...

yea lol
but i mean, its a 3.5L
and only churning out 160-180bhp?
makes me mad knowing my friends integra is a 1.8 and makes 195 crank

i think it handles well, especially for a 4700lb boat at that

i just dont have that oomph! i need
ill be trying to get to 35 and it feels like its taking forever, and im pressing the pedal down a good inch to an inch and a half

and on my moms honda, i let my foot barely sit on the pedal, and it leaps to 35?
idk maybe its just me

hahaha i wish i could afford a TCD kit
they are clean

but i need to save my money for my project car in the summer

EG6 hatchback, K20A2 (type s) motor swap, intake, exhaust, K-PRO, and a good tune
and a bunch of other this and thats for the car

It is a 3.5L from 1968 that doesn't like to rev much beyond 5. That means, unless you have a huge displacement motor, no matter what kind, it will not make more power than torque. (hp/tq=5250, if memory serves) The Hondas also have an absuredly high diff ratio, which is why their transmission gearing is spaced so wide.

Also, the 1.8 makes how much torque, and when does it do it? The M30 makes 90% of max torque from 2k-5k. Smaller engines making similar power are much peakier and have zero torque.

Considering your car isn't operating correctly, before upgrading, fix what is wrong. Based on your description, you would get a good bit of performance back.

Some darn good qadvice on here..

Also, some advice form my albuquerque locals:


THere is absolutely no comaprison between an e23 with an auto and an e23 with a manual. ABoslutley none. The techs described it as having 100 foot pounds of torque and 50 horsepower. THe old autos, especially the EH models as I have, are brutally heavy, enneficient, and absorb tons of power. According the the BMW guys, they never even shifted right from the factory.


I told you about that 733 I bought? It runs like a raped ape and feels about 500 pounds lighter although it isnt.


Buy an old manual 733 car and swap the the transmission...most bang for your buck and its just not that tough. I think the hardest part is removing the damn 12' cooler lines.

Uh, the E38 weighs about 4,250...Not sure what an E23 weighs, but it's certainly less than mine...

Wrong, I weighed mine...

Brace for impact:

IN Roswell, with gas in the tank: 4310 pounds.

Wrong, I weighed mine...

Brace for impact:

IN Roswell, with gas in the tank: 4310 pounds.

Not trying to start a battle, but something is wrong with the weight figures being thrown around here...

The numbers I see have the E23 at a max of about 3,900 pounds. This makes sense, as it shares many of the same pieces (though it has a longer wheelbase) as the former E28 535i I had - a car that weighed about 3,300 pounds.

Even with the extra leather on the L7, I just don't see how it could weigh 4,300+ pounds, unless there were either live people in the seats or dead ones in the trunk...?

Could be the extra leather , the extra power seats, power headrests, insulation in the trunk, rubber mat, ABS system, Airbag system, huge factory cat..stuff adds up, Ive had it out, and its heavy


I wish it was 3900 pounds


Of course, 20 gallons of fuel is 120 pounds so that puts a 3900 pound car at 4020 pounds right there

yea, its a 7, id wayy rather have tq than hp

his type r motor makes peak tq at 7000 and hp at 8000-8400?

i like my tq down low

i looked on the side of my door for the weight lol
it was more around 46**lbs
idk if thats with gas and BS

Lol raped ape, im going to start saying that now
yea theres so many junked up 733i's in the bay area, no prob finding one
the years dont matter right?

actually, do you know anyone in cali who would do the whole swap for me? find the tranny, and do all the BS?
i dont want to put my uncle through it, and i dont have the time?

Hey you could always go up to 12:1 compression if you want to add octane boosters with every fill up since if memory serves correct Cali only has 91 octane gas max. That should add some power!:devillook:rolleyes

FI cheaper than compression and yeilds more power

umm lol yea forget that
yea, stupid cali, 91 octane max
i run 87 anyways :P
with 8.0:1 comp, it should be happy

Fuel Injection?
Forced Induction?
lol sry

anyone think i would pass smog if i got a tcd kit? not the visual part lol, the actual smogging part?
maybe with 2 cats or something?

Forced Induction is the better way because it can be turned down for better mileage and when I was in Cali with the 93 740 I had to constantly add octane boosters because my car pings and detonates if you give it less than 93 octane gas.

i looked on the side of my door for the weight lol
it was more around 46**lbs
idk if thats with gas and BS

I believe the 46xx number is a gross (max) vehicle weight - fuel, passengers, etc.

ooo lol
i dont really know what detonation sounds like?

ooo haha got it
so it doesnt say how much the car weighs?

I really didn't notice the noise but rather the vibration from the detonation because it made a weird sensation.:stickoutt But really, it vibrated the hell out of my car just going down a block and coming back.:nono

You should use empty weight most of the time for weight comparing because it is the most accurate for when it is just you with an almost completely empty trunk. Gross vehicle weight is a 150 pound person in each seat, 150 pounds in the trunk, and a full tank of gas which is why mine is like 5400 something.

You could pull off a trans swap in less than 1 weekend, if you get all the parts.

ooo, my car misfires during cold startups, and when i hold the gas and rev it to 1k-1.5k the engine shakes like crazy, and it idles pretty rough, but i dont think i feel any vibrations once its warmed up and not idling?

so it doesnt say the empty weight anywhere on the car?


thats the thing, im not sure exactly what parts i need and what problems might come up, im more of a honda person, if theres something wrong with my car, i just take it to my uncle, but he lives 70 miles away and is busy most of the time, how much do you think it would cost to do the swap? and i cant seem to find any manual 733i's or 735i's?

The labor in the swa, if you want to pay somebody..would go like this

Remove and install pedal box and master cylinder.
Remove automatic transmission
Remove auto trans control module (like .3)
Remove auto trans cooler lines
Plug radiator holes
Install new clutch
Install shifter
Install new driveshaft
Install New interior shifter boot

lol you make it sound easy
i wish someone would just sell the whole kit haha

(i thought this was kind of funny)

i was driving up the driveway in reverse today, and the rpm's were at 1k
i get out of the car and there is two black tire marks going up the entire driveway, its uphill lol

heavy ol f*cks haha

Still cant figure out why I am driving mine when I have my 740

id drive whichever one id rather not care about if it got in an accident as much, if i had a choice, i only have one car lol

im trying to convince my dad to work on another e30 325i
he used to love his old one until he totaled it, hasnt suped up any of his cars ever since, sucks