Welcome to my world, my world of turbos, tyre smoke, and tuning...
Tuning cars, driving cars, testing parts, and complaining about everything. It's my job, and a the majority of my non-work life too...
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This is another thing I see all too often, and that's people obsessing over creating a cold air feed for their turbocharged engine, and usually at the same time neglecting other things that have a far bigger effect on performance.
It's all well and good having a fully enclosed cold air feed to your turbo, but if it's too small, and in most instances it is, it doesn't matter how cold the air is, your car will perform worse in every way than if you had a totally nonrestrictive air feed, even if it sucked in full engine bay temp air. While a cold air feed is a bonus on a turbo car, it's really, truly, not a big deal, and not something I'd exchange for even the slightest restriction. Unlike with N/A, the air goes through the turbo compressor, heating it up hugely, regardless of how cool it is, and then, providing you've got a good setup, it goes through a highly efficient intercooler and exits at a very low temp indeed; way below 40degC. If 1deg increase in compressor inlet temp equaled 1deg increase in intercooler outlet temp, it would seem more useful, but unfortunately it doesn't work like that. Also, while under-bonnet air temps are high when static or on an engine dyno, in the real world, ie when you're flying down the road under full load, the engine bay air is moving so fast that any one portion of air is under the bonnet for such a tiny amount of time they don't get a chance to get hot, so, well, they're not... Finally, and perhaps most importantly, is any restriction. While you can't see or feel it until it's SO bad it's actually sucking your inlet pipe shut, trust me, fit a vac gauge to 80% of turbo inlet pipes and there will be a restriction. Any restriction at all decreases compressor efficiency, which in turn increases compressor outlet temps, totally negating the usefulness of any 'cold air feed', not to mention needing more 'power' on the turbine side to spin the compressor, which will increase pre-turbine backpressure, which then is bad for temps, performance, and reliability. BASICALLY, while cold air is always, always good, it comes a big big big second place behind having a massive and nonrestrictive air feed. Huge air filters and 4in inlet pipes for all! Performance camshafts are wonderful things, and play a massive part in how an engine drives, but one thing they do NOT do when fitted to a factory turbocharged engine, is help the turbo spool up faster.
Some of you reading this might be thinking "Duuh, no shit, tell us something even more obvious" but for years, over a decade in fact, especially in the Japanese car tuning scene in the UK (but it seems to spread elsewhere too; I've heard it a fair bit even with Renault 5 GT Turbo owners lately), I hear people saying this like it's a fact, despite it much more likely to do exactly the opposite! This does seem to be a UK-only thing; overly wild cams on turbo engines aren't common elsewhere in the world that I've noticed. Whether this is better knowledge elsewhere, or less unscrupulous tuners selling cams by telling bare faced lies to convince people it's needed to improve spool, you decide... Don't believe me? Well, there's enough dyno sheets out there to compare which prove it, but the production car world is a big hint that these magic 'anti-lag' cams are utter bollocks, as all production turbo engines are fitted with much milder cams than the production non-turbo version of that engine. From Fords to Porsches and everything in between, that's a fact. Do you really think they did it to make the cars laggier and have less low down grunt? No. The fact is, cams are very give and take, and increasing cam duration (and overlap) reduces low down power, not increases it, and instead improves performance higher in the rev range instead. A well-specced mildly uprated cam may well not noticeably slow spool over a factory turbo camshaft, and may indeed give a much stronger midrange when it's matched well to the turbocharger(s) fitted, but will it actually improve spoolup rpm? No. In fact, if you over-do the camshaft you can totally RUIN a turbo engines performance, both spool and top end power, and this is something I've experienced a number of times (not from my own choice, I must add!). I've seen (but wasn't consulted on, as if so I would've told them it was going to be a disaster) a magazine test of some "Fast Road" cams on a VAG 1.8T engine running the stock KKK K03 turbocharger. I knew even these fairly mild cams were far too big for the athmatic little K03, and lo and behold, the car lost a huge amount of performance from low rpm to high, compared to the standard cams. Another good example was when a frien bought a Renault 5 GT Turbo modified by the previous owner. The engine was a good spec and fitted with a Piper 285 cam, which I know from previous experience is a fantastic cam for the little C1J lump as long as you've got a decent size turbo fitted to it, but this car had a standard Garrett T2 running 15psi boost. While the turbo didn't really spool much slower than standard, the longer duration still reduced lower rpm power compared to the standard cam, and as revs increased the restrictive little turbine of the T2 combined with the increased overlap of the cam (high pre-turbine backpressure and big cams REALLY don't mix!) meant the engine was completely dead on it's ass by 5000rpm- Lower rpm with the standard cam, making for a slower car everywhere in the rpm range. When this exact same engine was fitted with a turbo of a more suitable size for the cam (A Garrett GT2560R running 23psi), the engine was transformed, and now makes well over twice the power, and revs hard all the way to 7500rpm, while only running 8psi more boost. Didn't spool faster though ;) "Turbo Cams" are one hell of a big subject, and one I'll be gradually covering on this website in various forms no doubt, but this 'lag thing is the biggest issue... Everyone seems to know me as that fountain of (pretty geeky) tech knowledge on tuning, especially anything turbo related, as well as the person who does unusual projects and goes against the grain when it comes to tuning. I'm contacted constantly by strangers asking for tuning advice as I seem to have become known for my no BS and 'Experience only' advice, and due to this people have, for years, said to me "You should start a website/business giving your advice, it would do really well".
The thing is, aside from total lack of time to do this, my question always has been "But how the hellfuckshit does a website of my knowledge, experiences, and opinions going to make me any money, regardless of its popularity?". Well to be fair I've yet to work that bit out, but I've came up with a plan of how I'd like the site to look and read, and I've got so many things that's worth sharing, I've decided it's worth a punt, and hopefully something worthwhile comes of it before I give up! So here's how it's gonna work... Basically, rather than the enormous tech features or reviews I write for magazines, which I will still do of course, what's going to be on here is going to be no less detailed or useful, in fact maybe more so, but it will be on one small subject at a time, so like "Turbine housing A/Rs" as one post, rather than the entire subject of turbos in one big lump. It won't just be straight up tech info either, it will be a LOT of reviews, but on things I've experienced, and very honest too, no cliches or bullshit; what I'm saying is what I've experienced of it. It will be car/tuning parts I've used, tuners I've dealt with, and of course cars I've driven, both standard and tuned. Reviews will be both things I've experienced years ago, plus anything new I experience. HOPEFULLY Stav-Tech becomes popular, and companies contact me asking if I'd like to review their parts/cars/whatever too, which will allow some more in-depth reviews with better pics too (as I have to go through my archive etc for old ones!) but we will see what happens. This website is going to be ME, and because of that it'll have some swearing, and no doubt WILL have controversial opinions, which to be fair is why a lot of people like my opinion, as it's not the usual cliche'd rubbish that most stuff regarding performance cars and performance tuning is! However, what I'm NOT though is some kind of awful shock jock, Katie Hopkins, type of person who says things are shit just to stir up controversy, as frankly that boils my piss and smacks of someone who can't become well known just for being good. What I am though is HONEST, and my controversial stuff will just as much be me saying things are far BETTER than popular myth says they are, as me saying they're worse. If something's better than people think, I'll say so, and if something's over-rated, trust me, I'll say it! So where do we go from here? Well, I suck at the internet, so bear with me when it comes to the website's layout, as I've a LOT to learn, so apologies this isn't the slickest most amazing looking website- It's not about that though, it's about good info. Regarding when I post, I'd hope to add something on here every day, or every other day, or a couple times a week, who knows, I've not tried yet, but every day if possible! I won't post stuff just for the sake of it though. All killer, no filler. Cheers! |
Hi, I'm Stav...You may or may not have heard of me, but I've spent the last 20 years working full-time in the tuning scene, and the last decade or so writing for various car magazines. Archives
March 2024
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