Power Secrets (useful Reading & Perhaps Advice)

[DrSarty 90 1 Cars]

Hi all:

 

There was a US tuning magazine in the barber's shop at the US Marine Corps camp I visited (called Leatherneck) in Helmand Province in Afghanistan. It had quite a down to earth, non-Yank article which I am happy to reproduce here in part, and will add more if people ask.

 

What I liked about it was that it was a classic European car (a BMW E30 M3), and the tests were done in a methodical, back-to-back fashion showing the improvements (if any) of several basic checks and then alleged performance enhancing modifications, namely:

 

> Basic HT component upgrade/refresh (plugs, leads, rotor arm)

 

> Valve clearance check

> 'Performance' fluid swap

> 'Performance' Air filter

> Fuel filter refresh

> Injector 'upgrade'

> 'Sports' exhaust

> Chip 'upgrade'

 

The tests were all done with oil and cylinder head temps checked and nominally the same. The mods were also done one at a time. This is what also made it a good test which showed down to earth, non-manufacturer Max Power-esque biased results, which I feel justify many of the recurring and mature comments appearing on this wise forum in 'getting more power' topics/threads.

 

If you wish me to reproduce snippets of the relevant sections on each of the modifications above I will, but for now I thought I'd just leave you with the conclusion.

 

What did we learn?

Our parts bill topped $2,000 (about £1,500) and we spent half a day on the dyno. We picked up about 5bhp and 5lbft of torque. Outwardly, it doesn't seem like we got our money's worth.

 

True, we could've skipped the exhaust upgrade and lived with the whimpy stock exhuast note and that would've saved us about £400. Likewise, staying with the OE injectors would've saved us even more.

 

Similarly, swapping the injectors, the HT tune-up components and fuel filter only proved to us that the items on the car were working fine anyway. (Sarty note: a bloody expensive way to find that out!)

 

In short we needed the time on the dyno to prove that our already fitted components were working fine. A harsh reality, but you don't know if something's working until you test it.

 

The silver lining to our test is that while our maximum numbers didn't increase this much, we picked up a lot of area under the curve. At some RPM points we saw double-digit horsepower and torque increases.

 

Additionally, the numbers don't indicate how much better the car now drives. Our M3 has been transformed. It now sounds right (*Sarty cough*) and makes more power everywhere. Part-throttle performance is also significantly improved.

Ask if you'd like to know more from the article on the individual elements of the test.

 

No seriously. If this turns into a decent thread, perhaps it can be pinned to help people on the hunt for more power from their engines, as there's some good advice here, backed up by sound evidence.

 

The bottom line in my opinion is that a good healthy engine is actually a very good thing to have; make sure you have that first. Performance modifications that really bring benefit, not only cost reasonable money (i.e. they are NOT cheap) but involve fundamentally changing the engine. This in turn means that most of these aftermarket mods in themselves are a waste of time, money and effort.

 

*Flame suit on. Flame proof socks, gloves and boots on. Helmet donned; visor down; awaiting a barrage of abuse*

 

Edited March 28, 2010 by DrSarty

[Guest steveontwin40s]

Good topic to bring up, just as iv posted a 'more power' topic!

so really be happy with what you got or get something faster in the first place!

For me though i like bolting shiny, noisy and exspencive parts onto my pug for the hell of it, half the fun.

is a fair comment though, peugeot spent years developing the 205 gti as its mile stone car that really pulled them from certain boxy boring doom (505, 305 ect..) and made people think 'crist they know what there doin, what a high tech lil car' (or sumin like that) and all we wana do is bolt stuff on from ebay and such- guilty.

 

So lets all stand up and say NO theres no point!

 

Standard Cars Rule!!!!! - No? didnt think so!!

 

(not abuse btw, just a opinion!)

 

 

Steve

Edited March 28, 2010 by steveontwin40s

[rescue dude 0]

What was the magazine?

Just wondering if I could find the article on T'internet.

[large 33]

I have to agree with the Dr on this. We all know an air filter on its own will not give you 10bhp.

 

I think how a lot of company’s get away with misleading info is to tune and engine to a pretty high level leaving the std air filter in place. Run it on the rollers then change there item (I have no idea why I am picking on air filters) and all being well they get a 10 bhp increase.

 

I had a GTi6 with exhort, k&n and ecu remapped. When I put it on the rollers the engine had 1K on it and it made 176bhp. the rollers I used are known to be a bit optimistic with the fly wheel readings but I can't remember the ATW fig. If the reading is right the bhp to £ ratio worked out as 1bhp:£100. I think this is the sort of money a lot of people spend on trying to get a little more power,

is it worth it? No. I would have been much better off going on holiday and getting a sun tan. .

[MrG 3]

at the end of the day you get what you pay for I suppose, cheap ebay fixes and fold flat seats won't turn the car into a fire breather (despite what the ads say) but will give the libido affect of feeling faster, but I suppose if that's your aim then spend a day cleaning it and the feeling will be there all the same and you'd have saved about £60!

 

I think today many feel that a bolt on this and that will give the desired results where as Rich is right in saying that if the car is in poor health before, it'll still be in poor health after, so best start with a good base with a healthy engine and go from there. You hear a number of times where people have had a go at the traffic light grand prix with their 'tuned' motors only to find they can just about keep with the apparent std car and therefore question whether it is std. It probably just boiled down to the fact that it was a nice std looked after car in the first place.

 

Also sometimes a different way of driving may well improve things more than fitting bits to it, you see so many times a good driver driving a std car nice and smoothly and going damn fast, where as you also see the opposite, a 'tuned' car being driven badly and barely making progress on the other.

 

I found this the hard way by as well, and it cost me money, but now its done, I'm happy, the car provides all the laughs and does keep up with the apparent 'better' machinery, so I'm happy with my progress.

 

I like the std car, always have, but if you are prepared to do the research and accept that you may have to spend a lot more than you first anticipated then you won't go too far wrong.

Edited March 28, 2010 by MrG

[DrSarty 90 1 Cars]

Thanks for the comments.

 

If it's come across as a "Don't bother tuning you car" type of thread, it wasn't meant that way. It's more of a spend your money wisely type affair, highlighting that many of these aftermarket mods (however nice and shiny and easy to bolt on) are most likely a waste of your time and effort.

 

This doesn't mean leave it standard though; I'm just trying to help people get more bang for their buck.

 

What I am stressing is get your baseline/starting point right in the first place.

 

That said: if you want to spend £3,456 on shiny s*it from Halfrauds that makes you feel good and excites your arse dyno then crack on. It's your money.

 

Anyway: the magazine was 'Grassroots Motorsport'. I can't tell you the age/issue number as I tore the pages out; but the article is called 'Power Secrets'.

 

To show what I meant by more info:

 

1) OE 'S14' engine power spec (at the flywheel): 192bhp / 170lbft torque

 

2) Baseline test (no mods - at the rear wheels): 171.9bhp / 161lbft *Pretty good for an old engine that*

 

3) Basic HT component tune-up: 173bhp / no change

{i.e. New NGK spark plugs, new rotor arm and dizzy cap plus Magnecore HT leads (which have no power claim improvements BTW)}

 

4) Change to Redline synthetic lubricants: No change / 163.6lbft

{i.e. New engine, transmission and diff oil}

 

5) K&N OE replacement panel filter: 174.4bhp / 164.4lbft *So whilst I wait for a torrent of abuse on this one, that's £40-50 plus your time for.....1.4 horses!!*

{I'd also add that we don't know whether the OE paper filter - that costs about 12p - was in good condition or not, which makes the above doubly meaningless, if you only look at peak power figures.}

 

It goes on. But in summary, the fuel filter was swapped for a new OE one and gained nearly another 1lbft of torque. £80 spent on servicing the injectors (my apologies - I thought they were upgrades) actually dropped bhp and torque, as did a £400 exhaust system, in fact 2 digits on each measurement.

 

And I suppose the point about the exhaust is my real point. It makes the car sound 'nicer', but not be 'faster'.

 

And finally, the biggest improvement....(?)

[DrSarty 90 1 Cars]

...well it was a chip upgrade.

 

This yielded the largest improvement in one hit, of all of the other 'mods' or refreshes put together: 175.6bhp / 166.7lbft.

 

Naturally that's just peak; but I suspect this mod also contributed to the largest, average 'under the curve' increase, making the car not only quicker overall and in more situations, but more pleasing to drive.

 

I deduce/conclude from all this, that IF the car's components are sound - even if they're just OE - the best improvement you can make is fully mappable (or really well pre-mapped) fuelling and ignition.

 

The downside of this is of course that it means lots of people sell chips, as everything I've waffled on about here is not a revelation. I am not the Messiah!

 

I just attempted in one hit to summarise tuning principles at a very basic level, addressing what quick mods make any difference.

Edited March 29, 2010 by DrSarty

[RossD 43]

But what are the chances that the "increases" were all down to dyno innacuracy? Do 5 dyno runs, each an hour or so apart and chances are you will see slight subtle changes (i.e another bhp here or there).

 

The gist of the article is totally correct though and just confirms pretty much what we've all known for years anyway

[welshpug 1,626]

That's also assuming that the S14 engines actually do all make 192 bhp / 170 lbft when new.

 

Something quite similar happened with my 205, ran like a bag of nails due to a handful of shafted Jetronic components and poor wiring, I gradually replaced more and more components, getting an exhaust and a K&N fitted along the way.

 

In its last guise with Jetronic it made 121.8 bhp and 116 lbft, the only change between then and the next RR run at the same place was the fitment of Motronic and the return of the o.e airbox, it made 132.7 bhp and 123 lbft.

 

And not just different peak figures, under 3k was a vast improvement, torque shifted up the rev range 700 rpm but power peak exactly the same place (no difference in cam timing at all)

 

Granted it was on different days but that's quite a difference to simply put down to margin of error.

[GilesW 41]

I think the first thing about tuning a car is maximising what you already have.

A point proved on a re-run of top gear on Dave the other day - they had to make a renualt avent (?) thingy lap as quick as an evo.

 

They eventually rolling roaded it - 150.7bhp, when the standard out the factory (5 years earlier) is just over 200!

So a good service and a check to make sure things are working right would instanatly gain them 33% more power - an amazing amount for likely very little £'s, especially when you look at how much it costs to start improving power from the standard starting point.

[Batfink 201]

You can look at maximum figures and be disappointed but you have to look at the bigger picture.

The silver lining to our test is that while our maximum numbers didn't increase this much, we picked up a lot of area under the curve. At some RPM points we saw double-digit horsepower and torque increases.

 

to me this is the interesting part.

 

My engine had throttlebodies fitted and was only 15bhp up on standard but across the whole curve I saw some very good gains over standard.

[brumster 135 1 Cars]

I'd also wonder about the ~1bhp differences and consider that even a dyno environment cannot be perfectly controlled in terms of air temperature, density, pressure and other factors that are simply out of the control of anyone on God's earth. So that percentile here or there might be down to the component, or might not, or might be partially. You see 1bhp from doing this or that, but in reality the air temperature was a couple of degrees cooler, or some bearing grease in the dyno had moved, yada yada

 

Don't get me wrong, you've got to go with what you can do, and this sounds about as methodical as they could physically achieve. Sounds like a good article, and nothing surprising. Let's face it, as you well know Dr.S (and many others on here with what I'd call "high spec" engines), the sort of power increases we enjoy don't come cheap. When you've paid £aaargh for that extra 90bhp over standard and someone comes along and says they can get another 20 horses from just spending a few hundred quid, sometimes there's no telling them.

 

Shame they didn't do a fuel comparison. I'd love to see some practical, methodical results on stepping up to VMax for example. I'm fairly confident there is a gain to be seen there, but would be interesting if they'd have included that. "Hey, do nothing to your car, just put this in and presto...!"

 

Mind you at todays prices, probably still an expensive £/bhp!

[Tom Fenton 1,526]

The numbers don't always tell the whole story as is alluded to above.

 

My shared 205 Mi track day car was rolling roaded ages ago and made a solid 170bhp and I think 131ft/lb with a decent exhaust and an air filter. Whether this was right or wrong isn't really important.

 

With the addition of throttle bodies and an ECU, it made 177bhp and 145ft/lb last summer. To say my mate Phil who had put many many hours into making a job of the conversion was disappointed is an understatement.

 

However some of this disappointment has gone away with a trip to Cadwell last week. I had driven a lot of laps of Cadwell with the engine in its original guise, so had a number of benchmarks to do a real comparison with. To put it simply the car is now far faster than the numbers alone would suggest. Previously Coppice (left hander at end of straight) with enough bollocks could be taken flat in 4th at circa 100mph. Now the car will pull 100mph about 2/3 of the way down the straight on to nearly 110 and needs a good dab of brake before turning in.

Previously it would maintain its speed climbing up the Park straight in 4th gear but not accelerate. Now it will pull all the way up the straight. etc etc.

[DrSarty 90 1 Cars]

I am really delighted people have seen this thread for what it was meant to be. Namely the importance of the area under the curve, and that many tuning mods are basically nonsense.

 

Again: this wasn't supposed to be something people didn't know, only it all thrown into one thread to perhaps answer some of the recurring questions concerning tuning from some newer members. I hope it doesn't disappoint them.

 

Incidentally regarding fuel types. A friend of mine with a digital TV box had a few old recording which I waded through, and it included the 5th Gear 'episode' where they tested fuels back to back, and the Shell Optimax did actually bring about a large improvement, but ONLY on the really newer, hyper-managed, top spec cars (IIRC). BP Ultimate didn't fare as well actually.

 

I'm not sure, but with many of our cars on here (mine included) that do have (expensive) aftermarket management, I suspect it makes a difference too.

 

Anyone have any comments on that? Anyone say they really, truly notice a difference in using these more expensive fuels (Optimax / BP Ultimate), or is it just arse-dyno and wallet glow?

[Tom Fenton 1,526]

The fuel can only really make any difference on an engine equipped with a knock sensor, that can advance the ignition timing to take advantage of the octane in the fuel.

 

Anything without a knock sensor needs to be mapped on the intended fuel to take advantage of it. Our Mi16 was mapped on super so we use super.

[brumster 135 1 Cars]

Anyone have any comments on that? Anyone say they really, truly notice a difference in using these more expensive fuels (Optimax / BP Ultimate), or is it just arse-dyno and wallet glow?

 

It's more a case of it was mapped on it, and without a knock sensor I don't want to risk running it on anything lower-spec. Longman told me not to, as have many others.

 

I know guys who run WRC fuel. Their engine builders have told them it's not really so much about power, but that it burns cleanly and quickly and is just better for the engine internals in the long run - ie. it will save them money in engine rebuilds. Can't vouch for the truth myself, but I guess it makes sense when you're running a £10k+ engine, why scrimp on the fuel !

 

I know a guy who runs a 205 rally car who swears by Tesco 99.

[MrG 3]

Mines not the most highly tuned 8v in the world but it performs incredibly well on Tesco's 99. At Snetterton I used BP in the morning (as that was in the tank) and then used the cans I took with me and that was Tesco's finest, and the difference was marked. Pulled better, felt crisper and cleaner in fact better all round. But then again it was set up to run on Tesco's 99 when being sorted on the RR.

[harryskid 193]

I use to run a Ford RS turbo back in the 80s and spent £250 on a chip upgrade. It was money well spent, 1600 with no turbo lag and shed loads of power. It never went on a rolling road so i don't know how many bhp it made but it sure use to piss off a lot of BMW drivers.

[24seven 104]

Interesting results. Chip upgrades are a dark dingy corner in the tuning room in my mind. When done properly they work, and there is a very good reason for them to work as well (efficiency vs performance vs stoichiometric ratio vs emissions regulations and all that), but it's because they work that you get all these bogus eBay specials and so on that do nothing.

 

That's also assuming that the S14 engines actually do all make 192 bhp / 170 lbft when new.

 

Something quite similar happened with my 205, ran like a bag of nails due to a handful of shafted Jetronic components and poor wiring, I gradually replaced more and more components, getting an exhaust and a K&N fitted along the way.

 

In its last guise with Jetronic it made 121.8 bhp and 116 lbft, the only change between then and the next RR run at the same place was the fitment of Motronic and the return of the o.e airbox, it made 132.7 bhp and 123 lbft.

 

And not just different peak figures, under 3k was a vast improvement, torque shifted up the rev range 700 rpm but power peak exactly the same place (no difference in cam timing at all)

 

Granted it was on different days but that's quite a difference to simply put down to margin of error.

 

 

Since converting my Mi16 from 2 row to 3 row motronic with knock sensor it runs incredibly smoother all through the range. Much more low RPM performance, idles perfectly all the time, uses less fuel and to some extent feels faster at full throttle (though that may just be my arse dyno telling lies just because it's happier with everything else). This first hand experience coupled with a lot of the stuff we've been studying at uni recently has actually really enlightened me as to how our engines (more specifically motronic managed) are controlled.

 

Yesterday driving back from Swansea to Llandudno (circa 180 miles) I put £20 of normal Tesco 95 in (the light wasn't on yet) instead of the usual 99 because I'm skint atm. Last time I did this run I put £20 super in at 115.9p, but since then 95 has gone up to the same price. Though the car didn't run any worse, I coughed to a stop with just enough momentum to pull into a petrol station 4 miles from home. the same amount of super always easily sees me home, and then another 30 or so motorway mile round trip on top of that to go to my mates place and back. Coupled to that I spent the whole drive taking it easy because I've a couple of mechanical woes atm whereas usually I give it the beans on 1/2 of the better roads on the trip, the MPG difference really surprised me! On the 2 row ecu I didn't compare mileage between different fuels, because without a shadow of a doubt the car ran better (less kangarooing, smoother idle etc) on Tesco 99 than anything else, V-power, Ultimate, Esso 97 included. Over the summer when money's not as tight I'll compare the different brands of super and see which one comes out best.

[CaptainK 11]

I am really delighted people have seen this thread for what it was meant to be. Namely the importance of the area under the curve, and that many tuning mods are basically nonsense.

Agreed, its all about the useable power across the whole rev range. When I got Sandy to fit my ITBS and map it I asked for a more punchier low to mid range map with more useable power across the rev range, rather than a "Look at me, I've got tons of pub talking peak BHP" map. The car drives so much more quickly now and is an absolute hoot at any rev in the range, instead of previously waiting for the big power higher up the rev range.