Way off topic, but still related

[SEB]

Ok i came here in hope that guys that have decent knowledge can help me.
I drive a BMW and most of the guys there havent even taken apart an engine, much less know how one works. Im a big fan of anything Dodge related, or muscle cars for that matter. Im not bashing young guys like myself (im 21) but most people on the boards i go to are morons and have the ricer mentality.

So here is my question.

Generally speaking, im working with a 2.7 liter SOHC engine. It produces 174 foot pounds of torque, and about 132 HP stock.
Compression ratio: 8.5:1
Bore/stroke: 84x81 mm
Now this engine was meant for economy, it uses a bigger stroke than its 2.5 liter counterpart, they share the same inline 6 cylinder motor.
Now ok i get this bigger stroke increases displacement obviously...but im trying to work with direct bolt ons.
The stock compression is 8.5:1.
My goal is to make it a low RPM powerplant, and put a bigger gear ratio like a 2.93 or 3.25 instead of a 4.10 to make up for the loss of revs, because the engine will be a low revving high torque engine. Thats my goal at least.

Ok basically, im asking these things:
How much more torque do you think you can achieve with 10.5:1 compression, a bigger cam like 292 duration, the stock is like 260 or something weak..dynamically balancing EVERYTHING, basically blueprinting, performance bearings to withstand the heat and friction, decking the head as much as it will safely allow, you can deck it .020 until its too much.

People say this wont get you from 173 to around 200....they are joking right?

I dont get it, either they dont know what they are talking about or is something wrong?

I know that even doing a cam and rockers on a muscle car is at LEAST 30 torque at the very extreme. Like a 454 or whatnot. Is asking for 240 torque too much?
I dont understand how it cant produce that much power.
I mean if a 502 cubic inch can produce at least 502 torque, why not a BMW with newer technology? 1988 car by the way.

I know this doesnt belong here but i want peoples opinions that have decent experience racing, building engines, that are at least my parents age or understand cars at least!
thanks for your help/opinions.

My first car would have been a challenger if the previous owner didnt wreck it 3 days before i was supposed to buy it

[ntstlgl1970]

Since it is an 88, the first thing I have to ask is, where do you live, and what smog laws do you have to contend with. Second, is there aftermarket support for your injection system if you change cams/compression/gear ratio? Might be a good idea to look over the Dinan website for some hints as to what they do to increase torque in these cars. Comparing performance increases between V8's/V6's and 4 cylinders is apples to oranges (or tomatoes).

[SEB]

unfortunately im in Cali....THE worst state to do anything in. But im going to just swap engines come time to smog like a lot of guys to. Im almost done restoring the interior of my car, and suspension, so im concentrating on doing the motor next.
I like the engine/block that is in there because its so light.
if a advanced fuel injection system is what you were talking about, there is a standalone fuel managment system, or megasquit, and there is a thing that me and another guy asked to make for his car, which is the same as mine, which controls fuel and spark as you please. I heard that tuning is what really unlocks the torque and horsepower to a huge degree, or running at the richest point before it no longer helps.
How did you know about Dinan? Thats a big BMW tuner!
the cam we used for his car was a 272 regrind, which is 272 duration, i know thats not too much but the schrick cam was like 400 bucks. I guess you cant put a price on power but he was on a budget.
On my car, i put a 3.73 LSD from the stock 3.25 LAS for more low end, it revs a lot obviously, but its a problem cause i cant get past 5300 RPM, and the power band is 3200 to 4800 RPM. Its a low revving high torque engine basically.
My main goal is to raise the torque specifically a lot more vs horsepower.

Also is it true that a inline 6 is more smooth than a V-8? thats what people say but i would think more cylinders is more smooth


here are some pics, not completely good quality. And not as nice as your guys' classics.
The interior, once i get my floormats back in after i clean it up, put in the glovebox again, and do the headliner, will be completely restored interior.
I put on a big 535is exhaust, and its super quiet and provides a lot of back pressure, makes acceleration smooth and good on the bottom end.

[Bullitt-]

I don't know didly about BMWs or even hopping up a 6cyl. but it seems to me a reasonalbe aproach to this would be an overdrive unit. BTW good lookin car.

[Chryco Psycho]

inline 6 may or may not be smoother , that really comes down to balancing but they will produce more torque
changing cams is science , more duration will increase RPM generally depending on the CL & overlap designed into the cam & still be smog friendly as well but you would need to have the cam carefully designed to do what you need
How much power could be gained specifically is hard to say , porting the heads ,free flowing exhaust / headers can make a huge difference , I have worked with the Mopar slant 6 & seen some decent gains with mild work but they are never a powerhouse engine

[SEB]

Yeah my goal is at LEAST 220 foot pounds of torque at the wheels.
I hope thats not too much asking with a redesgined cam, higher compression pistons, custom forged rods. There is a direct replacement crankshaft that is forged. I wonder if that really is better.
From a respectable company called metric mechanic, they have proven, ported a head to flow like 16% better as well.
Also they have a direct bolt on throttle body and intake manifld, which are bigger. I would think that, that means more top end though.
So will the cam (getting a custom one) change specifically where the torque comes and and how much?
I was always told like on V-8 engines that a bigger stroke for displacement generally increases low RPM torque, and the cam controls the powerband, specifically where power will be produced.
thanks for your help

[Chryco Psycho]

cam design can help build cylinder pressure at any rpm depending what it is designed for ,other factors like rod ratio & stroke will make a difference in torque output as well
Ported heads Can increase power at almost any RPM as well depending if the heads is enlarged or just cleaned up to reduce torbulence in the flow ,same is true of the intake
forged cranks are stronger but in your case I doubt it would be needed ,unless the cranks are known to be weak

[Stacked440]

Well...my  on the whole thing is head work?  Everything else in the motor is just there to keep it together , a good flowing head makes for one hell of a runner.  But on a BMW like that, I'd start with maybe a new exhaust(or just a high flow Catalytic Converter) and maybe a bigger throttle body and or air intake, bigger injectors, etc etc.  The fact that you live in California can be a problem but also, you might want to look for an air injector.  It injects air into your exhaust diluting the over-all EPA un-friendlies that come out of your tailpipe.  Essentially the air injector doesn't do anything except help you pass emission inspection.  All Volvo 850's shipped to California had them equipped.  It really depends how you go about it, there is a plethora of parts out there to do all kinds of stuff to computer controlled cars(SuperChips, OBDII tuners, etc etc).  By the way, that is one CLEAN 88' BMW.  Seats look brand new!

[SEB]

thanks! ive put a couple grand into the interior to bring it back to stock.
im so close now, im just trying to get a torquey motor until i find a decent challenger i can restore or thats near restored.
thanks guys!