Critique my power mods!

[ihavefingers]

I'm getting pretty bored with the stock m20. ive had the car for awhile and only have a remus cat-back which pretty much does nothing. i'm looking to get a bit more poewr, not looking for anything crazy, and want to keep it pretty daily driver friendly, reliable and hassle free. I've put a bit of work into the engine recently to freshen it up, which actually helped.

so here's what im thinking..
Miller MAF/pro street induction kit.
W.A.R. chip (or open to others??)
larger injectors
extrude hone intake
headers (not sure which, Ireland Engineering has some new ones, i saw korman has a header?)
cat-less center section, maybe resonator, keep my remus cat-back. (no emissions where i live)
lightweight flywheel
aluminum alternator pully cause its cheap

i feel like all that added up could make for a pretty decent change.

i know thats getting up there in price, to do ALL that. i want to keep the m20, wont consider a swap, ive driven an s50 e30 and didnt like what it did to the handling.

so what do you think?

[E30-325iS]

Cam?

[FLG]

small turbo will probably make you happier then doing all that other work for really not much return.

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[nando]

ditching the cat isn't going to make a lick of difference in power

the WAR chip is going to be a waste of time on a build like this - it's still pretty stock.

since you haven't changed the displacement of the motor or increased flow at the head, there's not much point in larger injectors. having yours rebuilt might be a better investment.

headers are always a good idea. I like the way the new IE ones look - like a cross between Stahl and bavauto headers (neither of which are available I don't think?). Just don't go too large on the primaries because your engine is still stock. anything less than 1 1/2" should be OK.

the extrude honed intake is pretty much a waste of time on a stock head/motor. and it's expensive.. if it's not ~$700, it's not really an extrude honed intake either.

lightweight flywheel, unless you're talking about shaving a few lbs off your stock one, it's going to suck in DD traffic to drive around with an 8lb flywheel.

the alternator pulley, I'm not sure is worth it even if it's cheap.

overall I'm underwhelmed but that's why you asked, right? :)

I think I'd take all that money and get a head built with a mild cam and a chip tuned for it, and leave the rest alone, with maybe the headers hooked up to your stock cat. the PSIK is nice but it's really expensive and I'm still quite skeptical on the power gains claimed. up to you.

[berlow94]

+1 for cam and head work.

[Cabriolet]

I think I'd take all that money and get a head built with a mild cam and a chip tuned for it, and leave the rest alone, with maybe the headers hooked up to your stock cat. the PSIK is nice but it's really expensive and I'm still quite skeptical on the power gains claimed. up to you.

This cannot be stressed enough. getting the engine rebuilt isnt all that costly. chances are you have nearly 200k on your engine. getting all new bearing, hone the block and new rings will be better than adding a chip to a warn engine. getting the top end rebuilt can be done for <2k and will offer more performance that almost any other bolt on mod. My old car with just a chip and rebuilt stock engine could pull 4+ car lengths on a stock carand engine from 0-80mph. my good friend with a 2.9L stroker, chip, headers, cam, m30 afm could pull ~4 car lengths on my old car. doing a refresh and then building on that is the only way to do up an M20.

[CabbE30]

^ agreed. A fresh M20 will run circles around a worn out one.
My recommendation would be to get IE HD rockers, a higher performance cam, a (MarkD) chip and larger injectors (17.5 or 19#), and headers. That would be the best bang for your buck.

[digger]

why would anyone rebuild a M20B25 to almost stock specs when they dont have to abide by some regulation rules for a racing category or similar? i wouldnt be touching the bottom end unless you have a decent budget that allows more cubes. stick to bolt ons rebuilding engines costs alot

best to stick to boltons if on a budget

[Cabriolet]

why would anyone rebuild a M20B25 to almost stock specs when they dont have to abide by some regulation rules for a racing category or similar? i wouldnt be touching the bottom end unless you have a decent budget that allows more cubes. stick to bolt ons rebuilding engines costs alot

best to stick to boltons if on a budget

Because, as stated before. A refreshed engine is really enjoyable and a considerable power increase from a worn out tired one. You can easily do a quality refresh for less than $2000. Once you start screwing around with the bottom end, custom pistons, getting another crank etc that's when the price skyrockets. At that point swap it for an S5x because, it's money more wisely spent. Since, I do nearly all my own work I’ve refreshed 6 m20s (not including other engines) back to stock and have been more than happy with the results, considering it's less than $1500. Slap new injectors, a chip and headers on them and you have a damn nice car.

Bolting on crap to a tired engine puts more stress on worn parts, chance of failure increases and you don’t get the full benefit of any of those mods due to blow-by, friction and buildup. As any of the people who have been here a long time know, do maintenance first, then modification.

[ihavefingers]

My engine currently has around 115k miles, so not super high, and its had a decent amount of recent maintenance done. I think the miller PSIK, its not cheap, but for the claimed power gain, it definitely seems like the most bang for your buck if you really end up anywhere close. plus im coming from an AFM and no chip. I'd still like to do headers and a cat-less center section, if nothing else for the sound.

I dont have the time or money yet for a rebuild, and if i do rebuild, i figure i'll do it well and put a little more money into it. some of the rebuilds ive seen costing people in the 4-5k range seem like a pretty significant improvement. if I could have around 200whp out of a daily driver friendly, reliable engine id be very happy. I didnt buy this car for straight line performance, thats not really what im looking for, im more concerned with having a very usable engine, where you have good power available whenever you need it in the twisty stuff.

[ihavefingers]

Because, as stated before. A refreshed engine is really enjoyable and a considerable power increase from a worn out tired one. You can easily do a quality refresh for less than $2000. Once you start screwing around with the bottom end, custom pistons, getting another crank etc that's when the price skyrockets. At that point swap it for an S5x because, it's money more wisely spent. Since, I do nearly all my own work I’ve refreshed 6 m20s (not including other engines) back to stock and have been more than happy with the results, considering it's less than $1500. Slap new injectors, a chip and headers on them and you have a damn nice car.

Bolting on crap to a tired engine puts more stress on worn parts, chance of failure increases and you don’t get the full benefit of any of those mods due to blow-by, friction and buildup. As any of the people who have been here a long time know, do maintenance first, then modification.

And what wheel size, offset, and tire size are you running in that sig pic? just curious, looks perfect to me!

[nando]

You aren't getting 200whp out of your M20 with headers and an intake. even 200bhp isn't going to happen (a good reason Miller's claims of power increases are so suspect).

I still maintain a cat delete is pointless.

[Cabriolet]

And what wheel size, offset, and tire size are you running in that sig pic? just curious, looks perfect to me!

they are BBS RS's 16x8 et11 i believe. flush mounted. the back need about 10mm spacers tires are 225/45ZR16 i think.

nando is right. you are probably getting something close to 140whp now. the most you can really expect would be 155ish with a cam you could get to 170whp. but 200whp is very out of range in a NA build with a small budget. i think it cost my friend $6k to get to ~200whp and that was with him doing most of the work.

[digger]

Because, as stated before. A refreshed engine is really enjoyable and a considerable power increase from a worn out tired one. You can easily do a quality refresh for less than $2000. Once you start screwing around with the bottom end, custom pistons, getting another crank etc that's when the price skyrockets. At that point swap it for an S5x because, it's money more wisely spent. Since, I do nearly all my own work I’ve refreshed 6 m20s (not including other engines) back to stock and have been more than happy with the results, considering it's less than $1500. Slap new injectors, a chip and headers on them and you have a damn nice car.

Bolting on crap to a tired engine puts more stress on worn parts, chance of failure increases and you don’t get the full benefit of any of those mods due to blow-by, friction and buildup. As any of the people who have been here a long time know, do maintenance first, then modification.

if you consider 15whp significant.....the engine has 115k (apparently) and if so there is no point refreshing it if maintenance and oil changes have been done and a compression test is decent.

who said anything about custom pistons? get a M52 crank, the sleeve, eta rods, use your original pistons and for maybe $500-800 extra all up over a 2.5L build you have a 2.8L just as fresh and higher CR, more cubic inches, real gains...i say this only if you are redoing the bottom end why stay 2.5L over a 2.8L, BFYB is there,

[ihavefingers]

yeah i didnt mean i was expecting 200whp WITHOUT a rebuild. I meant that seems like a pretty good # when everythings done, rebuild, intake, exhaust and tuning. im not really concerned with the # anyway's i just want a pretty noticeable jump in power, response, and drivability.

i think a chip or PSIK will tide me over for the time being..

the stock m20 actually feels damn good, especially when you think its a 25 year old car, small 6cyl, im at a high elevation, etc.. ive driven a couple e30's, mine, a 325i with 160k miles, and an ix with over 200 and a chip. and mine feels like its got the most pep.
but it just feels sluggish in general, you get on the power out of a corner and there's not much kick, if your a little too low in the rev's you really notice it. I want to get rid of that, when i get on the power hard i want it to really respond.

speaking of the PSIK, it comes with its own software, but can you run any other chip with it? it seems like there's some debate whether the mark d chip or MAF conversion is the better mod. of course theres the W.A.R chip, but id like to avoid having to tune it, for now at least.