How much power should i expect?

[BobMarley]

I own a 1989 325is, currently in the shop for a 5spd swap. My plans for the car is an occasional track car but will mostly be driven daily. My first mod of course which i am in the process of ordering is Bilstein sports with IE stage 3 race springs so i can actually learn to control the car and drive it correctly (first RWD car) before i start doing power upgrades. As of now i am trying to figure out how much power i can expect from the parts i wish to purchase in the future.

Cone filter w/ heatshield
MarkD 93 octane chip (god bless FL for 93 octane)
Headers and straight pipe
M50 fuel injectors
4.10 diff
8lb flywheel
Schrick 288 cam

I know some of the mods wont show on a dyno, but how would the actual performance aspect improve over stock. Im only 17 so these parts will take me awhile to purchase, i just want an idea of what my car could be in the future

- James -

[Rob]

its almost impossible to predict dyno figures, there are way way too many variables. Instead, you should do a before and after dyno, and focus not on the Peak numbers, but the deltas (areas under the curves) and how they change.

[nando]

I'm not sure if I would do a 288 shrick on the street, my 284/272 is just at the edge of being streetable IMO. still idles smooth but there's a lot of lope in the idle, not to mentioned the increased valve noise of the cam+headers..

[mikeedler]

288 will be just fine! I had a 290 dibilias cam in a car over here, acts a little stupid once in a while, but all in all it was fine, just takes a little getting used to. I dont think those mods will make an insane amount of extra power, but they will def. make the car more fun to drive, and all the noise will make it seem alot faster too.

[Calvin Tan]

I own a 1989 325is, currently in the shop for a 5spd swap. My plans for the car is an occasional track car but will mostly be driven daily. My first mod of course which i am in the process of ordering is Bilstein sports with IE stage 3 race springs so i can actually learn to control the car and drive it correctly (first RWD car) before i start doing power upgrades. As of now i am trying to figure out how much power i can expect from the parts i wish to purchase in the future.

Cone filter w/ heatshield
MarkD 93 octane chip (god bless FL for 93 octane)
Headers and straight pipe
M50 fuel injectors
4.10 diff
8lb flywheel
Schrick 288 cam

I know some of the mods wont show on a dyno, but how would the actual performance aspect improve over stock. Im only 17 so these parts will take me awhile to purchase, i just want an idea of what my car could be in the future

- James -

With all these mods, probably you will get around 20+ hp more at the crank.
I'm using Schrick 288...bad idle good top speed... Since you are looking for Cone filter w/ heatshield why not try this Cool air intake

[Borat]

A decent, well tuned headers and exhaust system can do wonders for M20. Combined with chip and cam. You could probably expect around 160 - 170 rwhp. I have seen dyno plots from other M20 with just headers/exhaust/timing advance so don't flame please guys.

[JeffBij]

I own a 1989 325is, currently in the shop for a 5spd swap. My plans for the car is an occasional track car but will mostly be driven daily. My first mod of course which i am in the process of ordering is Bilstein sports with IE stage 3 race springs so i can actually learn to control the car and drive it correctly (first RWD car) before i start doing power upgrades. As of now i am trying to figure out how much power i can expect from the parts i wish to purchase in the future.

Cone filter w/ heatshield
MarkD 93 octane chip (god bless FL for 93 octane)
Headers and straight pipe
M50 fuel injectors
4.10 diff
8lb flywheel
Schrick 288 cam

I know some of the mods wont show on a dyno, but how would the actual performance aspect improve over stock. Im only 17 so these parts will take me awhile to purchase, i just want an idea of what my car could be in the future

- James -

James,

Finish the suspension upgrades first. Learn to drive the car first before worrying about power. Anyone can go fast in a straight line. Good drivers will catch them in the twisties. There are a lot of 2002 drivers out there that catch M3's in the corners and under braking. Keep the engine reliable and running smooth.

With the suspension, don't forget the bushings, shock mounts, sway bars, stress bars, camber plates, AND BRAKES! Also, watch getting springs that are to stiff for a daily driver. You can always start with something like H&R Sport springs. You can always sell them and replace them with stiffer ones later. Also, as you drop the ride height, you will increase the negative camber. Nice on the track, but your tire wear will increase dramatically.

A Cone filter w/ heat shield will get you a maybe 5-8 hp to the wheels. The chip, if it is a good one, a few more, usually at the higher rpm ranges however. Biggest benefit from both of these, will be improvements in torque and throttle response.

Headers and straight pipe 3 to 5??? Realize that you WILL loose torque if you drop the back pressure on the exhaust to far. I have a friend who built a Lo-cost 7 with a Miata engine and had to put a cat on it just to get back some of the torque.

A 4:10 diff won't add power, what it does is get you into the power band (4000-5500 rpm) quicker. The sacrifice here is lower top speed and some streetability as you will be shifting sooner and more often in daily driving.

Lightweight flywheel will help the hp TO THE WHEELS some since you aren't using it to turn the additional rotational mass. Also nice with heel/toe shifts since it allows faster rev matching. The trade-off is typically a rougher idle (the additional mass of the stock flywheel will smooth out the variation is idle rpm) and it is alot easier to stall the car.

Bigger injectors (i.e. higher fuel flow) are typically only needed when you start leaning out because of improved air flow (low restriction filter, headers, porting the intake manifold, extrusion honing the manifold, bigger throttle body, etc.). Also, if you get to the point of freeing up the air flow that much, you may need to get custom burned chip because the parameters will be to far out of the "stock" upgrade chip's ranges. Get a air/fuel mix gauge and determine if you are leaning out before going with the larger injectors.

As for the cams, they can be a big improvement. Just remember, the greater the duration, the rougher (and typically the higher) the idle. If your streeting the car most of the time, I would stay with maybe the 272 or 276 cam. You will probably need to replace the valve springs and retainers if you change the cam out. And watch the rocker arms. This is a common failure point on M20's, especially if you stress them more with the longer durations. If they break, it can be expensive.


Just my 2 cents.


Jeff B.
Roanoke, VA
1989 325i dedicated and fully prepared track car
2000 328Ci daily driver

[Dave]

James,

Finish the suspension upgrades first. Learn to drive the car first before worrying about power. Anyone can go fast in a straight line. Good drivers will catch them in the twisties. There are a lot of 2002 drivers out there that catch M3's in the corners and under braking. Keep the engine reliable and running smooth.

I agree with him. Having spent last weekend on the track for the first time in my 220+Hp car, and having to let Civics pass at times, and at times getting pointed by to pass a 'vette and Mustang 5.0, Hp is not all where its at.

Get the suspension sorted and learn to drive the car to its limits.

[BobMarley]

Wow guys thanks for all the info... It has been very helpful:). The twisties are way more fun anyways!

[PeaveyBassist]

To further emphasize the point, I rode with Alex Shchipkov in his '89 325i on c5 corvette's the track. He has about 165rwhp and we rode a c5 corvette's ASS for an entire lap until he pointed us by. Learn to drive.

Will

[nando]

I wouldn't waste money on a 272 cam.. it costs the same amount as the more agressive cams and won't give that much of a performance boost. I don't have experience with the 288, I just assumed it would be rougher, but my car runs pretty damn smooth with the 284 (better than it ever did stock, actually). my idle is stock as well (~600rpm, automatic).

[Slick92GS-R]

what part of Fla u located ?..

[King Luis]

i just like to point out that this is one of the best new user posts. a young guy wanting to know some basic performance mods and knowing that he has to learn how to drive a rwd car first. welcome to R3V.

[BobMarley]

what part of Fla u located ?..

I live in Deltona. It is like 40 min from Orlando

[BobMarley]

i just like to point out that this is one of the best new user posts. a young guy wanting to know some basic performance mods and knowing that he has to learn how to drive a rwd car first. welcome to R3V.

Thank You! Not all of us youngins are ricers:) . Even though it seems that way..