Latest petrol experiments

[hogweed]

I'm spending a lot of time trying to figure out what factors (apart from my right boot) affect consumption, and will keep posting the results here as I know peeps are interested.

It's a 325, with K@N panel filter, big throttle body, and Viper 2 chip...

1) Ecotek valve - made consumption very slightly worse, about 1mpg. It also made the car run a bit roughly when trying to just cruise slowly on a low throttle opening. DON'T waste your money.

2) Ran several tankfuls through her with injector cleaner, and find it hard to believe the results. I had been getting 20-24mpg depending on conditions, with maybe 26/27 on a long run - I'm now getting 26/27. And yesterday, after a long (150 miles) run the average had risen to 31mpg!!!

This is totally unknown to my motor... it would appear that blocked injectors are a real issue. The following from

http://www.teamdfl.com/bmw/e30/fuel/fueldflhtml.html :

" The problem with the Bosch 715 injector is in the flow rate: only 149cc/minute.

Why is this bad? Well, for the real answer, go to sdsefi.com (go there for the real answers to questions you may not even know you had and a lot of other really cool stuff) but suffice it to say we're running out of fuel. At stock fuel pressure levels, a 149cc/min injector can only support 29.8hp per cylinder, or 178.8 hp. Now, this is assuming a 14.7:1 AFR, a 100%duty cycle and NO clogging or dirt.

Your injectors are clogged 5% or more if they have over 20000 miles on them. "

When I went to the rolling road day near Brum, the guy said mine was underfuelling by about 20% at the top end... and it was still producing 171bhp, so what would it manage with clean injectors...

Be interested in opinions on all this...

[320Touring]

sounds like you have some tangible proof there mate!

what injector cleaner did you use?!may give mine a 'treat'

currently running a log of my fuel consumption (thanks for the idea Zayyan )

will post the results after about 1k miles so can show what the fuel costs of an 2.0 m20 is...

[Wilson325i]

mine was underfuelling by about 20% at the top end... and it was still producing 171bhp, so what would it manage with clean injectors...

Be interested in opinions on all this...

20% ??? efin hell!!!!!!!

[hogweed]

...that's what the rolling road guy said, they measure your gases as your car's on the rollers. But that may only be at the very top end. If you look at that link I posted, you'll see some interesting stuff - they guy that wrote that reckoned that the standard injectors can only deliver sufficient fuel for a maximum 178.8 bhp.

Now if that's true, a standard 325 producing 170-odd is fine... IF the injectors aren't blocked.

I seem to rememebr that ant of Zone fame had Bexley Motors fit a Schrick 272/284 cam to his Sport, and it ran lean at teh top end even with clean injectors, so they put E36 M3 ones in, which have a higher flow rate.

I have a set of them, but never got around to fitting them. When I get my Schrick, they'll go in then, see what happens!

It was just some cleaner I got out of Halfraud's - probably their own brand, 'cos old Hogweed is a cheapskate.

I'm very wary of claims people post on here for all sorts of things, so for everybody's information, the way I measure my mpg is like this: fill the car to the neck. Drive till near empty. Measure mileage covered; fill to the neck again, and measure how much fuel was used. Litres divided by 4.544 = gallons; divide mileage covered by this number to get mpg.

The OBC bears no relatonship whatsoever to reality - on my car anyway.

[Karan]

my sport runs stock injectors to make 213hp..... this can be acheived by fitting a remote fuel pressure regulator and upping the fuel pressure....

Karan

[hogweed]

my sport runs stock injectors to make 213hp..... this can be acheived by fitting a remote fuel pressure regulator and upping the fuel pressure....

Yeah... I know you can do it that way too. I don't really know the pros and cons of each method to be honest.

[Zayyan]

currently running a log of my fuel consumption (thanks for the idea Zayyan )

It's not an "idea"....it's a miser's way of life!

I'll be interested to find out the results of these experiments considering that by just making my driving style more "mature" I got just under 40mpg on average over 1,500 miles from my 1.6i.

When it's back on the road I wonder if I can get 50

[Andy_magic]

I keep an eye on my cars fuel consumption too. It's a 320i with 186k on it.

On friday I drove to Cambridge, picked a mate up, then onto Milton Keynes, back to cambridge and then back home.

Most of my driving is quite hard really, I usually sit at about 75-85 mph with the odd blast up to 6000 rpm through the gears. My car sits at 4k rpm at 80mph.

Then yesterday I drove up to Norwich and collected a complete motorbike in bits and put it in the car and returned home. It averaged out at 31mpg, the OBC reckoned 27.3M/G.

This is with lots of sound deadening material, LOTS of tools, 5 boxes I think and a massive sub in the boot. The car is also due for a service.

[Zayyan]

When I started logging my car had last been serviced 14,000 miles before (lazy mechanix "forgot" to do it but just reset the service light ) and it has just over 185k on it now. I always have to carry a lot of rubbish in the boot as well.....odd that 2 cars in need of a service with high mileages seem to produce pretty decent MPG?

[naylor04]

Is this injector cleaner your talking about something that goes into your fuel tank to mix with petrol , like say...... Redex for example ?

[Andy_magic]

I put it down to the basics of the cars being good, coupled with the 'free revving' nature of our 'nicely matured' power plants.

[Zayyan]

Jesus's 35mpg run with 215k on the clock in the touring with family and bootful of stuff further supports this idea...

I wonder if engines do really "loosen up" over time though or if it's just a series of coincidences

[Guest]

am i the only person that gets well over 300 miles in my sw/auto 325 cab???

[Zayyan]

How many miles on it?

[hogweed]

Is this injector cleaner your talking about something that goes into your fuel tank to mix with petrol , like say...... Redex for example ?

Yes that's it - not sure if it's exactly the same as Redex, it's literally called Injector Cleaner.

[Richy325iTouring]

im lucky to get 240 miles to a tank
and thats with sensible driving not that i do a lot of that

see entertaing thread in gallary section cough

[Andy_magic]

Tescos had a special offer on redex, it was 60p for a small bottle.

Dunno if its still on offer though

[Karan]

Tescos had a special offer on redex, it was 60p for a small bottle.

Dunno if its still on offer though

i used to use it on my iS.....

i wouldnt put any additive sh1t in the sport though....

i think an ultrasonic clean, good fuel/oil are the way to go with oil changes every 3k miles!

[Andy_magic]

You can't beat doing it properly.

When a company ultrasonics injectors do they strip them down or just drop the whole injector in and run it?

The reason is I have an ultrasonic machine somewhere.

[hogweed]

im lucky to get 240 miles to a tank
and thats with sensible driving not that i do a lot of that

Yeah mate, that's about right!

But I got 301 miles the other day. Actually, that's quite a good rough-and-ready mpg guide - the tank hold about 10 gallons, so just divide your mileage by 10 and you get an approximate mpg figure... so you're getting about 24.

I hope some of you guys will try the injector cleaning route, and let me know if it's just me...

I think the injectors would have to be pulsed open and closed whil in the ultrasonic, otherwise the cleaning fluid might not be able to get at the crud with the injector closed? Don't really know though...

[Jhonno]

the tank hold about 10 gallons, so just divide your mileage by 10 and you get an approximate mpg figure... so you're getting about 24

the tank holds between 12 and 13.5 depending on whether is the 55 litre or 62 litre tank..

[hogweed]

the tank holds between 12 and 13.5 depending on whether is the 55 litre or 62 litre tank..

That's interesting... shows how much I know!

Mine always takes around 45 litres to fill up. I suppose I don't wait till the light comes on, so more accurately shoudl say that in PRACTICE it holds 10 gallons, if you see what I mean, because most people won't let it go to completely empty before filling up....

And it shouldn't affect the mpg calculation, because you're measuring the amount taken to fill it right up vs the distance covered...

[astondg]

I got my injectors ultrasonic cleaned about 6 to 8 months ago and I can't say it made any difference to my 323i. They were supposed to be flowing about 75% to 80% before they were cleaned and about 96% to 98% after but there was no noticable difference in performance or petrol consumption, although right now I think my petrol consumption is worse than when I bought the car. Odomoeter says about 260,000km (161,490 miles) now and it was about 250,000km (155,279 miles) when I got it about 1 1/2 to 2 years ago.

I guess it all depends on the specific car.

I have had the oil changed at least 4 times in that 10,000km (6,211 miles) as well (once when I first got it, again not long after, and two seperate occasions when I put hole in the sump, maybe a couple more times too) and it's had probably even more services, so it should be running perfectly.

Aston

[Andy_magic]

I know what you're saying about the injectors being pulsed while being cleaned.

I can probably take care of this as I have a complete spare engine managment system in the workshop, I could hook it up and feed signal into the crankshaft position sensor input to fool the ECU that the engine is running..

I think on the real high milers that things like valves & valve seats, bores, pistons & rings are going to be pretty worn so we won't see optimum fuel consumption. Anything over 30mpg is pretty good for such a low tech car.

[Widge]

And Magic if you go to the trouble of setting up an ultrasonic cleaning system, I'd happily pay you to do mine, and I've got a spare set so there ould be no hurry. If you have the time this could be a service that can be offered in the zone shop, when it's up and running, rather like the BBTB thingy. If you don't have time I'd be happy to do it too.

[Andy_magic]

what I'm going to do is test the rig out before I say yes, just to see if it works and if it's a worthwhile benefit to the injectors.

If it works as well as Im hoping then I'll put a post up.

[320Touring]

what I'm going to do is test the rig out before I say yes, just to see if it works and if it's a worthwhile benefit to the injectors.

If it works as well as Im hoping then I'll put a post up.

result mate! top bloke and lets hope it all goes well

[doug325i]

I get between 310 -330 miles out of about 48 litres in my 325i touring, one week got up to 350!

I too will post my misers chart!


Doug

[TOURINGDADDY]

mine has 200000 on the clock and last week i got just short of 370 ou of a tank. Blackpool-Hull-home (portsmouth)

[hoshy]

The Lucas ASNU injector cleaner has a sonic tank with witres to pulse the injectors, when they're running the muck comes out of the top which is not submerged. You sometimes need to need to use an eye dropper to help the flow. some kind of capilery action guess... dunno.

May also be worth taking 6 tubes and an old injection rail to hook up a pressure tester and spray pattern tester. Leaky injectors are never good as are one with a bad spray pattern. the tuebs can also be marked to check that each injector flows within a few ml of the others.

You should also replace the filters in the injectors and when my father does them in the ASNU he replaces the filters, o-rings (top and bottom) and end caps. I think the end caps are done to expose the needle for better cleaning.

Incedentally I spent a couple of hours doing mine on 120k, m40 and they flowed just the same before and after and it made no difference to the car. I was a bit disappointed really

[zaust]

mine has 200000 on the clock and last week i got just short of 370 ou of a tank. Blackpool-Hull-home (portsmouth)

Thats nearly double my juice drinking companion. and im still not putting
enough fuel in at the top end.
as for injector cleaning, theres no sub for taking them out and doing properly. red x waist of time your better off buying a good octane booster
and runnig half a bottle every 10k (after cleaning the injectos though)

[JoeP]

mine has 200000 on the clock and last week i got just short of 370 ou of a tank. Blackpool-Hull-home (portsmouth)

Thats nearly double my juice drinking companion. and im still not putting
enough fuel in at the top end.
as for injector cleaning, theres no sub for taking them out and doing properly. red x waist of time your better off buying a good octane booster
and runnig half a bottle every 10k (after cleaning the injectos though)

Off topic. Have you spelt Hertfordshire wrong on purpose?

[buster]

" The problem with the Bosch 715 injector is in the flow rate: only 149cc/minute.

Why is this bad? Well, for the real answer, go to sdsefi.com (go there for the real answers to questions you may not even know you had and a lot of other really cool stuff) but suffice it to say we're running out of fuel. At stock fuel pressure levels, a 149cc/min injector can only support 29.8hp per cylinder, or 178.8 hp. Now, this is assuming a 14.7:1 AFR, a 100%duty cycle and NO clogging or dirt.

Your injectors are clogged 5% or more if they have over 20000 miles on them. "

When I went to the rolling road day near Brum, the guy said mine was underfuelling by about 20% at the top end... and it was still producing 171bhp, so what would it manage with clean injectors...

Be interested in opinions on all this...

This is why i was using 535 injectors in my sport.It did make a differance as at full throttle they were only working at approx 70%

cheers
andy

[zaust]

Yes that is spelt wrong for a reason and u are the first to notice,

did not think it was off topic ??

[JoeP]

Yes that is spelt wrong for a reason and u are the first to notice,
did not think it was off topic ??

Really, how is the spelling of Herts related to petrol experimentation?