Skimming, porting and polishing heads, enlarging inlet valves, putting in various sorts of better camshaft and so on, not to mention all the special manifolds, exhausts, carburettors etc., used to be a thriving aftermarket industry which seems to have disappeared anyway for current cars. The normal way to tweak a modern car seems to be to alter the fuelling and ignition timing by 'chipping' it.
Is there nothing to be gained by, for example, grinding the sharp edges off the sealing face of the inlet valves - profiling is it? - and slightly enlarging inlet tracts and ports, or has modern computerised design and manufacturing made everything so perfect that only immense expense will improve engines much?
Very hot engines used to be thirsty and I suppose extra polluting. I suppose it is because of emission regulations that this sort of thing isn't done any more. But does anyone know of a firm that fettles engines in a mechanical way, not just by chipping, without charging more than the cost of a new engine? I have been wondering about this for some time. Cars and Car Conversions, an old favourite of mine, doesn't seem to exist these days.
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I forgot to mention engine balancing. Again, I suppose most engines are better balanced new than they used to be, but does anyone still do this just to improve their road machine?
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Far too much hassle Lud. Chipping's a piece of cake.
Although do you reckon i can drop a 2.0 lump out of a Primera into my Almera?
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The engineering is probably so much better today that there is little to be gained by those methods. In addition stripping down a modern engine would be prohibitively expensive in most cases, unlike the days when you could whip the head off yourself in about half an hour. It would take that long now before you could clear enough gear out of the way so that you could even see the lump.
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In those days lud, you had 90 bhp stock, and teaking this and porting that would get you 2 bhp here, 3 bhp there, possibly 15 bhp in total with a lot of work.
These days you have 130 bhp stock, and with a quick "chipping" you can get to 170bhp.
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TourVanMan TM < Ex RF >
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Most performance mods these days seem to be based around chipping as you point out, and altering intake / exhaust. I suppose one factor is that modern cars are so much more powerful than they used to be, that there is less significance in gaining a few extra HP the 'old' way. It's interesting though - say you had an old carl like a Capri or something, how much gain was there to be had from carying out the proceedures you outlined in the OP?
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But a fully balanced motor that ran perfectly was always better than a random production unit unless it was a miraculously good one.
Point taken about the tiresome complexity of modern units (and they get brain damage too if you so much as look at them). But: can anyone tell me whether a full balance and a lick at the edge of the inlet valves and a few other 'blueprinting' moves will make a worthwhile improvement?
A properly put together unit used to last longer in press-on conditions than a thrashed production one. Felt better too, and that made the whole operation of going quickly faster and safer.
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>But: can anyone tell me whether a full balance and a lick at the edge of the inlet valves and a >few other 'blueprinting' moves will make a worthwhile improvement?
No, not when control of the whole burn process is outside the engine internals and in a black box.
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TourVanMan TM < Ex RF >
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Obviously when necessary you get some teenage witches with Ipods or whatever theyare called to tweak the black box too TVM... Indeed that's what most people do isn't it?
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I recently did a 'head job' on, what I suppose is now, an old Fiat 'FIRE' engine because the emissions were dodgy due to too close tolerances on exhaust valve clearances. One exhaust valve was burnt (but 'ground in' ok), all other valves were re-ground using grinding paste, and a wooden tool with suckers on the end. Particular attention was paid to cleaning up the inlet valves. I didn't de-coke the pistons.
The re-shimmed end result was very satisfactory, with clean emissions, smooth running (I could balance a pound coin on the engine at tick-over) and much better 'drive-ability'.
I expect it would cost a fortune at a garage - far more than the fiscal value of it.
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In answer yes with all this chipping etc
Mind you there is a firm advertising tuning for series landrover 2 1/4 petrols in varoius stages up to a claimed reliable 120BHP.......mmmmm
But as i can't see one chip, electronic or otherwise near my S111 landy, then this will be very much of the old school
Porting, different Distributer, cam. carb & exhaust manifold... The list goes on
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You want to tweak an engine, buy a motorcycle.
My ZRX 1100 would be around 95 - 100 bhp at the rear wheel in std form, a few tweaks (jetting / airfilter / Akrapovic titaniun exhaust) and it is 120! Reason - the engine is based on the 125 bhp (in std form) ZZR1100, a set of ZZR camshafts would raise it to (with the other tweaks) over 130bhp and stronger valve springs and an ECU tweak would raise the redline by 1000rpm, etc etc.
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Motorcycle engines suffer badly when forced to comply with increasingly vicious emissions and noise regulations. Hence they respond very well to aftermarket tuning which to all intents and purposes puts them back to how the engine designers wanted them.
Most modern fuel injected bike engines will yield a 10-15% power increase when fitted with a good aftermarket exhaust and a Power Commander (a device that plugs into the fuel injection system and alters the fuelling at different points in the rev range). Many bikes have to run almost dangerously lean to meet the regs, and devices like the Power Commander simply allow this forced leanness to be dialled out. For older carb'd bikes, a Dynojet kit and a good engine tuner can achieve something similar.
Then you have bikes like cheddar's which have engines which borrowed from sportsbikes and detuned heavily (for more midrange torque). This means theycan be put back to their standard state of tune quite easily and cheaply, in many cases yielding a fantastic power increase. Cheddar's projected increases are in fact conservative. I've seen ZZR1100s (same engine) making a dyno confirmed 160 bhp having had less than £1,000 spent on them.
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
97 Ford Fiesta 1.4 16v Chicane (for sale)
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All helped of course by the fact that the motorcycle MOT has no emissions check (yet!)
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
97 Ford Fiesta 1.4 16v Chicane (for sale)
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Have a look at Practical Performance Car magazine or Retro Cars (theres also a new one called Performance Tuner but I'm not familiar with it), it seems old style tuning still goes on but must be very much in decline. In PPC magazine a lot of the older cars featured have the traditional gas-flowing stuff done on the head, etc., but people don't seem to on newer cars as the gains are not worth bothering with.
Things that seem increasingly popular now are the use of aftermarket ECU's, bigger injectors, scrapping the inlet manifold in favour of motorbike throttle bodies; a recent development seems to be remapping to get the extra power potential from E85 fuel (not that you can buy it anywhere yet).
A lot of the cars featured in PPC mag tend to have engine swaps and tweaking rather than trying to squeeze maximum power out of an existing engine.
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This type of tuning is still fairly common for kit cars, as lots of them run relatively old engines where things like changing the cam or sticking on twin 45s can give decent gains and are fairly simple to do. Having a pre-90s registration also helps reduce the MOT emissions requirements, and a Q reg is something like pre-75 so visible smoke only. There are engine age based emissions checks during the SVA, but (currently) you can pretty much do what you want afterwards.
As more modern engines are becoming popular, like Rich says there's been a shift to reprogrammable ECUs and fuel injection, where tweaking the 3D map on a rolling road is the best way to start before modifying any of the engine's internals. There are even kit ECUs like the Megasquirt you can build yourself and modify the map on your home computer.
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That's a really good point - you see a lot of companies offering tuning parts and services for the likes of the Ford Zetec/Duratec and the K-series, but there are virtually no 2.0 LX Mondeos, Focuses or 1.8 Rover 400's screaming around with 200+ bhp. They must be going into kit cars.
For ordinary cars, I think it's a combination of strictly enforced emissions legislation (no such thing as a "lenient" MOT any more) and the sheer damn complexity of modern engine management systems with multiple interlinked and interdependent systems. If you disconnect or replace anything on a modern car, who knows what else it will break or cause to function differently? A whole round metal container of long wriggly things.....
Cheers
DP
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04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
97 Ford Fiesta 1.4 16v Chicane (for sale)
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There are even kit ECUs like the Megasquirt you can build yourself and modify the map on your home computer.
.....Then take it for a blast down the road and "blow it" in more ways than one....?
Have you any idea how much money I've made from sorting out the hapless victims of the "Chippers?"
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