|
|
May 13, 2012 10:56:39 GMT
|
I didnt think it was possible until i looked inside the 40BHP power chip that was fitted in the Saxo VTS that i've bought as a daily! Upon getting the car home and my girlfriend commenting on how it looked "like a drug dealers car" i thought i'd give it a good clean inside and out which is when i found this taped up under the dash on the passenger side: So i took it out and took it apart seeing as it looked like a childs toy And i found this at the heart of it: a plain old Variable resistor! Even though the manufacturer is charging £49+ for one of these new, you can make one for about 50p and a trip to maplins [joke] Proof that extreme power gains can be had for minimal costs [/joke] ;D ;D
|
|
Too many projects, not enough time.
|
|
|
|
|
May 13, 2012 11:13:36 GMT
|
what was it connected to? my brother got a VTS a couple of years ago (still sat in the garage...) that had been built as a road rally car, don't think it had actually done a proper road rally but was still full of mud and dents.... It had the MAP disconnected, NO lambda whatsoever! one of those godawful adjustable fuel pressure regulators, and a fecking paddle clutch! was a right curse word to manoeuvre about, needless to say it ran a lot better with a lambda boss welded to the 4 branch (bright spark had filled the original with weld instead of getting a 50p bung!) the MAP sensor connected, and the FPR reverted to standard is it something about the typical Saxo owner maybe?
|
|
|
|
|
|
May 13, 2012 11:16:10 GMT
|
its amazing how much you can pay for a variable resistor. the throttle position sensor for a polo 3f engine is just a variable resistor, but vw were asking over £75 for them last time I heard.
|
|
|
|
|
|
May 13, 2012 11:18:43 GMT
|
And of course the cliche Saxo owner neither cares nor probably knows about the problems of bore wash from overfueling...
|
|
|
|
|
|
May 13, 2012 11:23:05 GMT
|
Or running horribly lean from the eco setting! I think it was connected to the engine temp sensor so it confuses the ecu by fiddling the results. Needless to say, i wont be using it If anone wants it its £20 +p&p. Fair discount from the manufacturer price haha ;D ;D
|
|
Too many projects, not enough time.
|
|
|
|
May 13, 2012 11:24:13 GMT
|
|
|
|
|
|
|
May 13, 2012 11:47:31 GMT
|
Yeah, mine was fitted there. I've taken it out now though and noticed no difference in power!
Interesting article on the Honda though! You'd think they would have done it from the factory though if there wasn't any issues with it....
|
|
Too many projects, not enough time.
|
|
|
|
May 13, 2012 12:01:35 GMT
|
As the bloke says, the factory have tuned it to be able to run on lower octane fuel without pinging, and probably left in a fair bit of extra safety factor just in case. So, if you only use high-octane fuel you can turn the ignition timing up with no real penalty. If you then put in regular fuel it will probably ping, although it has a knock sensor to save you there anyway.
|
|
|
|
|
|
May 13, 2012 12:20:27 GMT
|
As I suspected I'm afraid, along with electric superchargers there's no easy road to more power. And in a complete turn around of my above statement, 40+bhp for 50p IS possible if you happens to already have a few plumbing fittings, some rubber pipe, and a Volvo turbo, laying around in your garage.
|
|
Volvo back as my main squeeze, more boost and some interior goodies on the way.
|
|
bortaf
Posted a lot
Posts: 4,549
|
|
May 13, 2012 16:27:01 GMT
|
And of course the cliche Saxo owner neither cares nor probably knows about the problems of bore wash from overfueling... Surely it wont do anything just overiding one sensor when there 3 or 4 more that govern the fueling makes no differance, the only system it will work on is an older non lambda one surely ?
|
|
R.I.P photobucket
|
|
|
|
|
May 13, 2012 16:51:51 GMT
|
Full throttle mixture is governed by a mix of the MAF, TPS, engine speed and temperature. The Lambda is only used on light-throttle cruise/idle/gentle acceleration really - if you tried to run an engine at lambda=1 at high speed and power you'd melt things quite quickly. So yes, by tricking the ECU into thinking that the engine is cold, you can make it add a lot more fuel.
I'm fairly sure that the Saxo (complete with obligatory fart cannon) I saw on the A1(M) that was chucking out more black smoke than a old lorry had one of these installed. It was so rich it was misfiring like nothing I've ever heard - no doubt the owner thought it sounded 'sporty'.
|
|
|
|
Copey
Posted a lot
Posts: 2,845
|
|
May 13, 2012 22:44:21 GMT
|
As I suspected I'm afraid, along with electric superchargers there's no easy road to more power. And in a complete turn around of my above statement, 40+bhp for 50p IS possible if you happens to already have a few plumbing fittings, some rubber pipe, and a Volvo turbo, laying around in your garage. home made bren device for the win
|
|
1990 Ford Sierra Sapphire GLSi with 2.0 Zetec 1985 Ford Capri 3.0 (was a 2.0 Laser originally)
|
|
RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
|
|
|
Surely it wont do anything just overiding one sensor when there 3 or 4 more that govern the fueling makes no differance, the only system it will work on is an older non lambda one surely ? As James says, the sensors don't work as back-ups for each other, but in conjunction to provide a more accurate result. Obviously it varies from make to make, but my understanding is that most systems use a series of primary sensors to determine the engine's position within the map, which is a function of load and engine speed, and then a set of secondary sensors that make small corrections to improve the efficiency further. The primary sensors are the crank speed and, and then some method of determining the load, which tends to be either a mass air flow sensor, or a manifold pressure sensor. The secondary sensors then provide a correction function, which can either be a fixed linear adjustment to the maps output (such as the air intake temperature), or it can be an additional correction map. (such as throttle position). Air intake temperature is usually required for systems that use MAP for their loading, as they need to know the density of air to determine how much is entering, while a MAF based system would only need it for extra fine tuning of the timing. Lambda is one of these secondary sensors, it just provides a correction factor to get the engine to aim for its target air fuel mix if it sees a problem. Engines with a wideband lambda can correct under load, but like James says, engines with narrowbands can only do it at cruise when you're aiming for stoichiometric to keep the cat happy. Obviously quite a few of them do more than one job, and some sensors aren't anything to do with the initial map, but may effect things, like a boost sensor on a MAF based engine which may control the actuator, but not have any real say over the fueling or timing. In the case of that Honda in the link, the air intake sensor tricked it into thinking it was taking in nice cold air, which made the timing advance, suiting the higher octane fuel. But it also tried to richen the mixture, as it was applying a correction to the fuel map thinking the air's more dense, so needing more fuel. But then then at cruise the lambda sensor was kicking in and correcting things back to stoichiometric. When they put their foot down things were getting richer though, because the narrowband lambda couldn't measure the intentionally richer mixtures under load, and the changes often happen too fast for the lambda to keep up with. (Plus fuel evaporation from the inlet ports walls screws things up under changing loadings.) (Sorry, I may have gone a bit ott with that reply, someone may find it useful/interesting anyway.) Tricking sensors with resistors can be an effective way of correcting the management when you've moved away from factory in other areas, but as with any other mod, it only works if you know what you're doing.
|
|
|
|
|
|
|
I take it you guys haven't heard of the potentiometer mod for diesels fitted with an electric pump then
|
|
|
|
scruff
Part of things
Posts: 621
|
|
|
dude: Nope - enlighten us
|
|
1994 Lotus Esprit - Fragile red turbo with pop up lights. 1980 Porsche 924 - Fragile red turbo with pop up lights.
I spy a trend...
|
|
cianha
Part of things
aka VDubbin
Posts: 923
|
|
|
I know on VW TDs as found in 90s Jettas (pre- PD engines) you could turn up the fuel pump for extra power, though your economy took a hit and it could get smoky!
|
|
|
|
|
|
|
Dude is on about the 'everymod' for tdi engines.
There are simple DIY insstructions all over the web for most makes and models - it's basically a resistor in line with the fuel pump which moves the rack in the pump further than the standard setting, so you get more fuel.
You can use a potentiometer to tweak things, or add an override for idle - as this mod upsets the idle if you push it too far.
Did it on my caddy - and it perked it right up - puts the management light on quite a bit though! Cost about £1! You can get exactly the same off the bay for around the £30-£40 mark!
Joe
|
|
|
|
|
|
May 14, 2012 10:28:07 GMT
|
I've got a similar "instant gain" mod on my mechanical diesel pump - Cost a couple of quid for the vac tube, but everything else was just junk/spare parts The LDA portion of the pump has boost fed into the top - the more boost there is, the further it gets pushed down. The further it's pushed down, the more fuel it will let you add. On mechanical pumps, fuel is merely limited by this action, so with no boost, the throttle is only actually doing anything for the first 1/5th of travel at most. After that point, it's just pulling against a spring, and not adding any extra fuel. What this mod does, is use the existing N75 solenoid from the EGR valve, and adding a switchable "suction" to the underside of that diaphragm, pulling it down, letting me shove in extra fuel for a faster getaway (Does make quite a bit of smoke too!) bottom: Old delivery valve from pump head, with brake pipe union top: DV and female brake union welded together top union: Boost feed bottom (covered in a black boot) : vent Shove some flared brake pipe into the modded DV, and replace the vent with this Fit to the N75 solenoid, and activate via a switch Annoyingly, the thread fitment isn't a very common one, but the delivery valve on one end, had the correct one! Not quite 50p, but still damned cheap for the amount of extra acceleration it gives!
|
|
You're like a crazy backyard genius!
|
|
|
|
May 14, 2012 11:48:14 GMT
|
As I suspected I'm afraid, along with electric superchargers there's no easy road to more power. And in a complete turn around of my above statement, 40+bhp for 50p IS possible if you happens to already have a few plumbing fittings, some rubber pipe, and a Volvo turbo, laying around in your garage. home made bren device for the win I bought my MBC despite them being easy to make, for 15 quid its not going to break the bank and with petrol it probably would have cost that much to get round and find all the parts to make one, bought a boost gauge as well although strictly speaking not needed as the ECU will cut fuel well before the engine reaches its boost level. Cost me 50 quid with all new piping, but I have around 50bhp more than stock so far, next mod is just a resistor on the ECU to fool the fuel cut and i can probably dig out another 20bhp.
|
|
Volvo back as my main squeeze, more boost and some interior goodies on the way.
|
|
Copey
Posted a lot
Posts: 2,845
|
|
May 14, 2012 11:52:42 GMT
|
yeah, i just bought one too, but its nice to see some ingenuity
|
|
1990 Ford Sierra Sapphire GLSi with 2.0 Zetec 1985 Ford Capri 3.0 (was a 2.0 Laser originally)
|
|
|