0-60 time in a 325i

[DRIFTBOY]

Yes, only more concise!

The amount of equivalent bhp per kg lost depends how much the car weighed to start with.

In this case (assuming it starts at 1150kg for example) each kg lost is worth the same as 0.14 bhp!

[march109]

Weight saving, in my opinion, is about the best modification there is.
Mainly because it is free - or even profitable if you sell some parts you take off!
It also helps cornering, braking and fuel consumption!

Forgot to say I agree totally. But would add, smaller wheels make more of a difference than you would think.

If you changed your alloys for ones that weighed 2kg less, (reputable sport wheel manufacturers qoute wheel masses, halfrauds don't) you would save 8kg all round the car, since this is worth 4 times as much in sprung weight terms this is 32kg. or about 10BHP.

So next time you see a chavved up nova on 17's driven by some racing god wanna be remember hes made his car slower because he knows nowt,

[Turbo-Brown]

<Alex starts to wish he'd not quoted blindly from AutoCar>

[DRIFTBOY]

Indeed!
Different size wheels and tyres make a difference.
As do diff ratios, tyre compound, road surface and it's temperature, condition of the clutch, air temperature and like has been mentioned the driver!

Magazines are often brutal when testing cars and will do repeated clutch burning, gearbox smashing, driveshaft snapping standing starts to get the absolute best results. Most journalists are quite handy behind the wheel too! Which certainly helps!

[t5psr]

I have a e30 2.7 stannard conversion (ex 325isport) was his son's car and has a full conversion reckoned to be putting out approx 215-220bhp I have an magazine with the my car in from oct94 it list's the 0-60 at 5.9secs and 0-100 at 14.9secs do you think these figurees ring true. thanks phil

[Gravy]

Weight saving, in my opinion, is about the best modification there is.
Mainly because it is free - or even profitable if you sell some parts you take off!
It also helps cornering, braking and fuel consumption!

Forgot to say I agree totally. But would add, smaller wheels make more of a difference than you would think.

If you changed your alloys for ones that weighed 2kg less, (reputable sport wheel manufacturers qoute wheel masses, halfrauds don't) you would save 8kg all round the car, since this is worth 4 times as much in sprung weight terms this is 32kg. or about 10BHP.

So next time you see a chavved up nova on 17's driven by some racing god wanna be remember hes made his car slower because he knows nowt,

LOL, you are so right!!!

[march109]

Also forgot to add, its not weight loss but mass loss.

Weight does not exist as a constant, it is a force derived from gravity

If an object had a mass of 1kg on earth it would have a mass of 1kg on the moon, even though it would weigh only 1/6 as much.

I had a physics teacher who was a petrol head, it was great!

[DRIFTBOY]

I have a e30 2.7 stannard conversion (ex 325isport) was his son's car and has a full conversion reckoned to be putting out approx 215-220bhp I have an magazine with the my car in from oct94 it list's the 0-60 at 5.9secs and 0-100 at 14.9secs do you think these figurees ring true. thanks phil



I think that is feasable to be honest.
I had a Nissan 200sx which was dynod at 201 bhp and I got that to 60mph in 6.1 seconds.
Did 1/4 mile in 14.9 also with dodgy clutch hydraulics and cheap tyres.
I think a Sierra Cosworth does low 6s with about 203bhp. ?

[DRIFTBOY]

Also forgot to add, its not weight loss but mass loss.

Weight does not exist as a constant, it is a force derived from gravity

Quite!

Maybe this 0-60 time was recorded at a massively high altitude with less gravity!

Oh, but the air would be less dense there!

This is getting silly now!

[march109]

Also forgot to add, its not weight loss but mass loss.

Weight does not exist as a constant, it is a force derived from gravity

Quite!

Maybe this 0-60 time was recorded at a massively high altitude with less gravity!

Oh, but the air would be less dense there!

This is getting silly now!

I was gonna say that!

[DRIFTBOY]

Anyway, because of all the variables that have been mentioned I personally think that 0-100mph or 1/4 mile times are a more accurate reflection of a car's accelaration.
Some cars will do 60 in second (some even in first) while some need to go to 3rd gear. Yet they may be in the same gear by 100.

For example - a car that will rocket to a max of 58mph in second gear will have a 0-60 time giving a misleading representation of it's performance because of having to change to third at the last minute!

And the longer the time and distance the acceleration is recorded over, the more accurate it becomes to compare car to car.

[march109]

Agree completly, I prefer 1/4 mile drag races.

American 1/8 mile is for pussies.

[DRIFTBOY]

Agree completly, I prefer 1/4 mile drag races.

American 1/8 mile is for pussies.

Agree with that too!

Damn - I've now got the urge to go to Santa pod.

Right this minute!

Do you think they'll be open?

[march109]

take the bolt cutters!

I'm trying to think of somewhere to go for a thrash too.

I need to buy a track slag.

[DRIFTBOY]

Double damn!

I'm on my 2nd tinny so I'm not driving anywhere!

The air is sooo cold and dense tonight too!

[Speedtouch]

K&N filters must make some improvement in airflow over standard paper type filters surely: the A-series tuning guru David Vizard rates them, and produced airflow graphs demonstrating pretty convincing stats compared to other types of filter. Even when dirty they still performed well. Being washable, they're good for 100,000 miles or so - hence are quite cost-effective too.

The Zone chip increases both torque and raises rev limit significantly: the two combined most definitely improved overall acceleration of my 325i.

[crazyenglishman]

No one has actually mentioned that a K&N won't drop the time by 0.5 second.
It will make it sound a bit throatier but make no difference to the time.
Sorry fella.

G

along with a better start i might loose .5

also got a welded diff now which would help.
i guess i will be running the strip on saturday then
i would hope for a mid 15 ish second run

[DRIFTBOY]

Yes, I have that A-series 'bible' too.
A fascinating book, and much of the theory relavant to any engine.

I think the problem that people have with K&N cone filters is that they can pick up a lot of under-bonnet heat in an E30, wheras a standard filter element is shielded quite well in it's air box.

It would be interesting to see a dyno comparison of standard and after market filters so that we could all know for sure what is what!

[dazleeds]

No one has actually mentioned that a K&N won't drop the time by 0.5 second.
It will make it sound a bit throatier but make no difference to the time.
Sorry fella.

G

along with a better start i might loose .5

also got a welded diff now which would help.
i guess i will be running the strip on saturday then
i would hope for a mid 15 ish second run

rwyb days sunday fella

dnt think youll get on the strip on saturday

[crazyenglishman]

hrm gutted
well i hope i can get on the drift track then

[Speedtouch]

DRIFTBOY, you can buy a K&N element that fits into the standard E30 airbox...around Ԛ£40.

[march109]

K&N filters must make some improvement in airflow over standard paper type filters surely:

No they don't, and when find the proof (other than ust my personal opinion I'll post it here, watch this space!

http://member.rivernet.com.au/btaylor/B ... dsE36.html
http://www.bolhuijo.com/airflowtest/
http://forum.e46fanatics.com/showthread.php?p=5065827


qoute: "Stock intake is a good design. It has the kidney snorkel feeding cold air to it AND a snorkel behind the driver side headlight also feeding some forced cold air for a ram type effect. How much better does it get. The cone filter-on-a-stick looses the pressurized design of the stock intake."

The general opinion os BMW air filters are like Porsche heads, they don't need any work. To get power gains from a K&N you would need a seriously large cold air feed, K&N qoute flow rates by testing in water this doesn't take account for air dynamics such as temperature.

The K&N is a cone and 360 degree field, therefore at least half of that cone is sucking up engine heated air, and your stock airbox has a torque improving cone that works just fine.

I just went back to stock after a brief flirt with cone filters.

[Speedtouch]

Like I told DRIFTBOY, you can buy a K&N element that fits inside the *standard* filter box - around Ԛ£40.

[DRIFTBOY]

I am aware of K&N panel filters, used one in my old Capri 2.8i. Thanks anyway though!
I'm using a K&N cone on my 335i at the moment because my donor 535i had it already.

Some interesting stuff there march109,
I think I might get a standard air box from a scrappy, a new oe (Mahle) element and try it.

And take it to a rolling road (which I want to do anyway) and try both there.

[Cotty]

checked the speedo on mine last week against the satnav and
mine only reads between 3&4mph over on the clocks

better than i expected tbh

On mine 80mph = 71mph on the GPS

Had the speedo reading 120mph a few time but obvioulsy well below that in reality

[Speedtouch]

Anyone know how much the OEM Mahle ones cost? (Just out of interest, as I'm quite happy with my K&N thanks!)

[fuzzy]

checked the speedo on mine last week against the satnav and
mine only reads between 3&4mph over on the clocks

better than i expected tbh

On mine 80mph = 71mph on the GPS

Had the speedo reading 120mph a few time but obvioulsy well below that in reality

i checked my speedo against my road angel gps and found the speedo to be roughly 10% out across the range 27@30,72@80 etc.i cant really believe a 325 with a k+n filter was timed in the 6 seconds though,a standard cossie with 204 bhp does 6.1 but that isnt held back with brick like aerodynamics

[rare]

Always have to take these kind of things with a pinch of salt.

You would be lucky to get mid 7's out of a strong 325i.

[csl]

Intresting thread,personally i can't see a virtually standard 325i pulling a 6 sec 0-62,however i've always got an open mind! I do think that a 325i (well maintained and favourable conditions) is faster than the 8.3 thats been posted(i know some r/tests suggest this 8.3 thou). I am a layman when it comes to hard timed figures thou,as i've never done a timed (offical) sprint,but know enough to know that there's loads of variables (such as driver skill etc.) and i respect this when people just blurt out a figure in a pub. Anyway , i thought you may be intrested in a few comparisons that i've got with my 325i (but please bear in mind these are my opinions only ) Figures in brackets are fastest-slowest 0-60 times from different mags at the time. FORD RACING PUMA(7.2/7.9)..........PUG.GRAND TOURISME(8.4/8.9) the 325i feels much quicker in straight line than these..............2WD+4WD COSWORTHS(5.7/6.2) 325i feels considerably slower.................. CLIO WILLIAMS(7.6) 325i feels on a par with this. Probably lots of worthless info to ya ,and these cars can't be compared in a like for like sense, but i just wanted to stick my 2 penarth in

[northloop]

This is quite a comical thread .......... I dont know alot about E30's but I know that a stripped one wont hit 60 in 6 seconds.

What size wheels do you have on your car? If you have changed them the speedo will of course be out, that can also change by running different profiles. I would suggest the speedo will be out by 10% anyway so your 60 is 54mph.

As a comparison a 172 clio weighing around the same as your E30 when stripped and with the same bhp makes the dash in 7.1 seconds. That will be with a test driver who has tried about 20 attempts to find the ultimate launch technicque.

Cheers for making me chuckle all the same

Gary

[ian325is]

Yip I agree. There is not a single magazine in the world that managed to to get a sub 8 sec time for the 0-100km/h dash. These are mostly scientific results with professional drivers. In SA we had BMW Motorsport developed 2.7's using lots of Alpina parts and lots of developments and these do the 0-100km/h dash in about 7.3 seconds. And let me tell you there is no comparison beween these cars and a standard 325i Sport. They are seriously quick! As a matter of interest, these 2.7's all came equiped with K&N panel filters, so they must work.

Ian

[march109]

http://209.85.135.104/search?q=cache:ZR ... =clnk&cd=9

Untill I see proof first hand I'm going to believe the people who have dyno'd K&N specifically on BMW engines, though someone has allready mentioned they will be testing soon.

And my point of view - K&N filters of all kinds feel like the increase HP when you first install them, because they do! You've ust taken out your dirtly filter and put in a new clean one, do it with OEM pieces you'll get the same result.

I'm very tempted myself to put it to the test but need to get mine running first, then theres the cost of the dyno runs and new filters to test.

[ian325is]

I've just read the article that you referred to. They lost horsepower when fitting a CONE filter and had minor gains with a K&N panel filter on a 318is. We all agree cones are not the way to go but BMW SA Motorsport would not have just stuck a K&N panel filter in without verifying the gains with plenty of dyno runs.

[DRIFTBOY]

Yeah, I intend to get my newly up and running 335i on a dyno soon, I hope. Just to get a power run and see if there are any problems that need looking at.

While I am there I'd like to swap my K&N cone filter (which came with my donor car) for a standard air box and standard element to compare the difference for myself.

I'm not expecting big increases or decreases or slashed 0-60 times but it would be interesting.

[awx]

I thought bigger wheels wouldnt put you speedo out. Thought bigger wheels affect the speed and acceleration, but your speedo would still remain the same as it gets calculated from the diff i thought?