simple cheap n effective mods 325i

Post Fri Oct 13, 2006 5:22 pm

hi guys ive just brought my self a 325i again, and was just wondering if there are any tried n tested simple cheap but affective mods that can be done to give it a little bit more get up n go, i have allready stripped her out which i must say has made the world of difference and is prob the best way 2 start. im not after massive power just more low down grunt. cheers in advance
wayne

Post Fri Oct 13, 2006 5:26 pm

You can bypass the throttle body heater, shown in excessive detail here:

http://www.cutestudio.net/doku.php?id=c ... :induction

which I thought improved low-end torque a bit specially in traffic.

Post Fri Oct 13, 2006 5:27 pm

probably best to get a chip from Ant

Ãƒ”šÃ‚£55 and you can fit yourself.

If you are gonna mess with air filters then forget any cone filter crap unless you are going to isolate it from any underbonnet heat and create a good cold air flow. Even then best sticking with standard airbox with K&N panel filter.

Exhaust system, but not cheap and power gains are minimal.

In short, it is not cheap to get power increases out of the M20 mill

Post Fri Oct 13, 2006 5:36 pm

hello and welcome! ive bought myself a 325i and have fitted an induction kit and soon im hoping a zone chip will find its way into the ecu fairly soon. a chip wont cost a fortune and will make a noticable difference. have a look on the technical / tuning forum as you will find a huge amount of info that you could put into use on your own car. the guys on here are really helpful and a wealth of knowledge so im sure if u ask nicely you will come away enlightened and inspired. good luck with ur mods, im sure one thing will lead to another, you know what these e30's are like!

Post Fri Oct 13, 2006 5:40 pm

will give the throttle body heater bypass a go this weekend, is the chip a noticeable difference?
was gonna add a panel filter apose to a cone anyway as heard alot of bad things about cone filters.

cheers wayne

Post Fri Oct 13, 2006 5:40 pm

I have done the cold charge mod when fitting the BBTB, I have also fitted the ITG zone filter, Scorpion Exhaust system and a Alpina 6 Branch next thing to be fitted is my wild chip fromAnt which I got of Ben.

The car does fell alot more responcive but next off is a live re-map

As said above no mod's are cheap but the zoners do sell and buy alot on here and thats were i got most of my bargins.

Post Fri Oct 13, 2006 5:50 pm

i put the induction kit on very soon after buying the car so i couldnt say if there is a difference or not( im not sure if it being an auto has any effect on how the induction noise would sound). didnt realise cone filters could have an adverse affect so im keen to hear if fellow zoners have had good/bad results with them.

Post Fri Oct 13, 2006 6:36 pm

great, ive just got a kn cone filter, should i stick it in the dustbin ?

Post Fri Oct 13, 2006 6:44 pm

tomtomiS wrote:didnt realise cone filters could have an adverse effect

My view of these is that you suck in warm air (lower power), they don't filter as well (bigger particles are ingested) and they may disrupt any tuned intake length.

Tuning an M20 IS possible without spending too much, the Ant chip is good and one will be mine someday, plus there is some experimental head work possible to do that is described here:

http://mototuneusa.com/thanx.htm

which is a long but worthwhile read. Basically part 1 involves constricting the inlet flow near the valve face to induce supersonic flow and thus turbulence to better fill the cylinder (because the air has more momentum), which some cunning application of JB-weld. Which is cheap.
Part 2 involves welding the aluminium to restrict the exhaust for the same effect, and leaving a sharp edge there so exhaust is never tempted back into the cylinder.
Part 0 is also interesting - which involves how to run your car in properly in the first place, the track gains for motorbikes being worth 2-10% supposedly.

So if you start with 175BHP and add 10 from the chip, 2 from the TBH bypass, 2 from changing the fan to an electric one, 10 from running it in properly and 20 from supersonic porting you might end up with
175 + 10 + 2 + 2 + 10 + 20 = 219BHP if it all goes to plan.

Additionally with the better intake mixing from the porting you may find you can bump up the compression ratio a tad.....

I aim to test at least part of this theory next year with my spare head wot I've got!

Post Sat Oct 14, 2006 8:53 am

So if you start with 175BHP and add 10 from the chip, 2 from the TBH bypass, 2 from changing the fan to an electric one, 10 from running it in properly and 20 from supersonic porting you might end up with
175 + 10 + 2 + 2 + 10 + 20 = 219BHP if it all goes to plan.

Perhaps one of the most optimistic power related posts on an M20 ever! start with 165, could be 5 either side of this, add 5 from a chip, 0.5 from bypass, 2? from electric fan, 10 from running it in properly? Not sure what you mean here tbh, but there would be some very well run in cars if you got 10 bhp for doing it, and probably about 10bhp from that headwork, on a good day.

165 + 5 + 0.5 + 2 + 0 + 10 = 182.5bhp, thats more like the M20 figures were used to, although still seems to high to me!

Post Sat Oct 14, 2006 11:58 am

Theo325 wrote:10 from running it in properly? Not sure what you mean here tbh,

If I wasn't optimistic I'd never get anything done

Seriously though - read the site. Reading takes a while but running in properly can make a huge difference. There are dyno maps and dyno figures on there, and photos of various pistons illustrating blowby etc, and by the time you (eventually) make it to article 24 you have a blow-by-blow photo assisted explanation about why you don't need to run in bearings. The tissue paper experiment is a real eye opener for plain bearings, one you can try for yourself and compare to his photos of plain bearing shells at various usages.

Running in properly eliminates ring blowby. Blow-by is when the rings do not properly seal, and this has the effect of losing power, wasting fuel, and ruining your engine oil with acidic combustion products. Running in properly (HARD) in the 1st 20 miles gives you that vital ring seal, giving you power and reliability.
This is worth 2-10% by looking at the motorcycle dyno evidence from Motomans site.

You must have met supposedly identical cars, where one goes better than the other?

Running in properly ALSO means changing the oil after the first 20 miles too. Otherwise all the tiny aluminium particles go round and burnish various surfaces which can affect plain bearings. When a plain bearing gets smaller due to burnishing you get a thinner oil film than designed - so your new 'blueprinted' engine becomes one of higher friction - costing power and efficiency. The guy explains on the website how a lot of his blueprinting work involved scraping off this layer - and anyway, the first 20 miles of bedding in the rings is going to give you the highest metal content in the oil anyway - not good enough to leave it in for the next 1000 miles!

New engines are obviously not a major concern of the M20 owner, but a rebored engine or a new cam etc. will be just the same. Cams are especially sensitive to running in poorly - the first 20minutes running a new cam should be above 2,000rpm or you'll spoil them. Luckily the cam instructions tell you this too!

The message is, for max power, run it in hard. This is free too

Post Sun Oct 15, 2006 10:20 am

explain how running an electric fan would gain you 2hp, how do you think the fan turns? it is turned by electrical power which is generated by the alternator, which is turned by the engine, more consumption from the battery (thanks to additional fan) will mean the alternator has to turn harder to compensate, thus where you gain by no clutch fan, you loose at the alternator.

furthermore the fan is on a clutch system so at higher engine speed it is practically disconnected from the engine, an electric fan will always draw power if its on, thus always sap engine power.

mrlee

Post Sun Oct 15, 2006 10:41 am

mrLEE30 wrote:explain how running an electric fan would gain you 2hp, how do you think the fan turns? it is turned by electrical power which is generated by the alternator, which is turned by the engine, more consumption from the battery (thanks to additional fan) will mean the alternator has to turn harder to compensate, thus where you gain by no clutch fan, you loose at the alternator.

furthermore the fan is on a clutch system so at higher engine speed it is practically disconnected from the engine, an electric fan will always draw power if its on, thus always sap engine power.

mrlee

Thank you, MrLEE. I couldn't be bothered to explain all that again.

Post Mon Oct 16, 2006 7:46 am

anytime mr moooore, although the simple answer it to put the fan on a switch and turn it off when you need the 2hp (or a realistic 0.2hp) boost, but then again your engine will run hot due to no cooling and rob you of power, so yes it really is true, one cannot break the laws of physics and principle of conservation of energy

shame really or else i simply use the engine to charge the battery and run each wheel from a 75kW fan motor and have a 4WD 400hp E30, easy when you ignore the boundries

mrlee

Post Mon Oct 16, 2006 8:08 am

Guess the arguement is that the fan only cycles in and out in slow or stop-start traffic and therefore only draws it's power for short periods, and when you're making full power, i.e. when going fast, the fan's not needed.

That said, my guess would be that the air blowing through the rad at 70mph pretty much makes the viscous draw no power as it is so the whole arguement's a load of poo really

Post Mon Oct 16, 2006 8:36 am

I was not saying an electric fan is not better, in theory it could be on a switch set to come on and off more precisely then the viscous clutch on a fan ever could thus engine temp would be more exactly controlled, what i was pointing out that swapping electric fan for viscous fan would not result in a 2hp gain. i would imagine even an electric fan at any speed over 40-50mph even if permanantly on would not draw any, or much, current to turn the blades, in fact by removal of pesky diodes etc you could set up the fan to charge the battery at higher speeds, now that may gain some power as the alternator would not have to work as hard, only thing to overcome at this point is air resistence due to turning the blades

mrlee

ps hows the GT6 coming on?

Post Mon Oct 16, 2006 8:37 am

At 70 MPH the air speed could even be driving the fan, adding power to the engine!

Post Mon Oct 16, 2006 9:12 am

didn't Ant put up a better TBH bypass thread connected to teh BBTB, cant find it anywhere, anyone?

Post Mon Oct 16, 2006 9:36 am

mrLEE30 wrote:explain how running an electric fan would gain you 2hp, how do you think the fan turns?

OK, the 2hp was just thrown into the pot, although looking how much power it takes to spin a similar sized fan round at 5,000rpm or so (can't recall the crank/fan gearing) I wouldn't be suprised!

If you look at the viscous coupling you'll notice that it has cooling fins on it, which dissipate heat. BMW didn't put the fins on for fun, so the heat must come from somewhere - there's nothing like a free lunch here.

Most of the time a fan is really needed when you're travelling very slowly - even in traffic or stopped. You don't care about losing power then.

When you're whizzing along (or accelerating at full power) at 40mph + the wind is enough to cool the rad - so you don't need to power the fan at all. You can therefore use the power you'd be spending powering the fan into going along.

The power difference might not be noticeable on it's own - but it will be there, quite how you'd measure it however I've no idea, rolling roads are stationary!! It's probably in the noise along with pumping up your tyres properly...

Post Mon Oct 16, 2006 9:42 am

Globulator wrote:

If you look at the viscous coupling you'll notice that it has cooling fins on it, which dissipate heat. BMW didn't put the fins on for fun,

These fins are to make the thing responsive to coolant temperature changes.

Post Mon Oct 16, 2006 10:51 am

Brianmoooore wrote:These fins are to make the thing responsive to coolant temperature changes.

Well I've learnt something today then

I'm guessing the viscous clutch grips more at higher temperatures - as it needs to move more air? I must take one apart one day and see what makes it tick...

P.S. Description found here:
http://www.freepatentsonline.com/4662495.pdf

Very interesting how it actually works, I'll have to say now that it is unlikely to waste much power if all is working correctly.