HP gain from chip, 2.5 exhaust, cam, and k&n panel filter?

[Adrian_Visser]

from what i've found searching (yes i did search before posting this) people are getting about 20rwhp from chip/ exhaust/ panel filter combos, without any headwork would a cam add much to this figure? also this is a car i'm about to buy and i never asked what chip it has, the cam is fairly mild it seems from the test drive.

[ethree]

What motor? Etas get a big boost from a chip "I" cars not so much. Either way I think 20whp is a bit optimistic.

[jlevie]

There's nothing to be gained from fiddling with the intake. The stock airbox and filter is just that good.

20rwhp from an M20B25 seems a bit optimistic to me, assuming we are talking about a street legal exhaust. You might get there with a race type exhaust (no cat's, 2-2.5" pipes, and terminated with a glasspack) and a chip, but it would really be too loud for the street. Great sound, but real loud.

[acefreely02]

with chip, cat delete and a good filter in stock airbox, mabe a straight throught muffler youl be able to see around the 10-13 whp mark,

a guy over on e30tech had done b4 dyno and after, total gain was only 13.6 hp at the wheels on a car 325i with around 120k on it

[nando]

the only way you're getting 20whp from chip/filter/exhaust is if you get real headers (stahl, supersprint, BTB, etc) and full custom exhaust (not a catback) which costs money. and most of the gains will be in torque, not HP.

[Adrian_Visser]

i guess i was being a bit liberal with my guesstimate lol. without headwork what would you see with a hotter cam (don't know what one to quote here the PO didn't know what exact cam it has in it) ?

ps. i'm sure this has been covered a zillion times i should proly spend more time searching

[MazterDizazter]

I've been searching also and all I get are people complaining about how it doesn't add any power..... I find this troublesome because I also own a Datsun 240Z and the L-series inline six can make 200bhp (starting from 150bhp or less) with about the same amount of work, and that engine doesn't even have a crossflow head design.

[nando]

i guess i was being a bit liberal with my guesstimate lol. without headwork what would you see with a hotter cam (don't know what one to quote here the PO didn't know what exact cam it has in it) ?

ps. i'm sure this has been covered a zillion times i should proly spend more time searching

it depends on the cam. also, it would be pointless to put a hot cam in the engine without doing headwork, exhaust, intake, and tuning. and bumping up the compression..

[StereoInstaller1]

BMW in general makes a vary balanced approach to their cars. The ETA is never gonna do much more in efficiency, as that is its goal. The "i" motor is never gonna make much more power without fairly serious mods, none of which will happen outside of the motor.

Want more power? Prepare for serious mods.

[wagonizzle]

Not to be all lame and boring about car modification, but do a comprehensive tuneup. It is true that this engine design was pretty well optimized form the factory. Make sure all of your ignition parts are new (plugs, wires, cap/rotor). Get a new air/fuel filter and change all your fluids. Dragging brake calipers and energy transfer loss through a sloppy drivetrain into resistant wheel bearings will lose as much power as you might get from 'modding' your intake and cam and exhaust stuff. You will have plenty of things to spend money on with maintenance, and while it may not be as sexy as a hot air intake, it will work better.

The only real decent mod per dollar on an 'i' car is a chip. Anything other than that is a waste of money if you are trying to gain power. If you have spent enough money to get your N/A m20 to make more than 25hp over stock at the wheels, you could have put that money towards a swap or FI and had 2-4x as much power.

Mod summary: It will never be fast in a straight line with a N/A m20 and that is why people who know more than me just say maintenance, chip, suspension rebuild and enjoy. Plus, it is more fun to drive a moderately powered car at 10/10ths than it is to drive a 'powerful' car 7/10ths because you/the road can't handle it.

[StereoInstaller1]

Mod summary: It will never be fast in a straight line with a N/A m20 and that is why people who know more than me just say maintenance, chip, suspension rebuild and enjoy. Plus, it is more fun to drive a moderately powered car at 10/10ths than it is to drive a 'powerful' car 7/10ths because you/the road or your drivers license can't handle it.

[wagonizzle]

haha good point luke

[n3nyongmini]

$/gains list?

Anybody do a $ to hp or tq gain list?

Something that starts with basics like chip then adds AFM, XX# injectors, cam etc ( I know there are alot of combos here) and then goes up to M5# or S5# swaps, metric mechanic units and beyond?

I searched and except for compiling my own I didn't see one.

If we could get real #'s I think it's make a great sticky FAQ.

Derek

[nando]

eh, it's not always about $/hp though. if it were we'd all be driving fox bodies.

[n3nyongmini]

eh, it's not always about $/hp though. if it were we'd all be driving fox bodies.

mulleticiuos

true, but at some point I will either need a rebuild or buy another e30 that needs one.

What the best bang for the buck if you had to replace an M20?

buy a few used one s and beat eh crap out of them?
rebuild it + bolt-ons?
bottom end /pistons/head /cam?
M5# or S5#?