Introduction
The aim of this guide is to provide an insight into the world of tuning the C20LET engine found in Calibra Turbos. The engine is on the whole very strong, with some good fundamental design characteristics. That said, there are several components that are either badly designed or restricting when you want more power.

This guide has excluded nitrous oxide as it circumvents several traditional tuning requirements (ie a standard KKK16 cannot produce more than about 300bhp without silly EGT, except when using nitrous). A further guide may follow. However, it must be said that nitrous is a very effective way of adding horsepower to any of the below setups instead of other expensive upgrades!

Any questions just ask!

Before you begin
Make sure your engine is serviced. No matter how much boost you run, no matter how many trick parts you have... you will produce LESS power than you should be if your engine is not serviced.

Make sure your plugs are in good condition and gapped correctly. Inspect and test your leads. Fit a new genuine Bosch rotor arm and distributor cap. Check the voltage at your fuel pump and make sure your cambelt, rollers, fuel filter and water pump are not due a change. Also make sure your actuator can hold the amount of boost you are wanting to create. Get a boost gauge too, and better still a wideband AFR 

Stage 1, 200-250bhp, under

Very useful Chav, Karma'd, now can you do one for the Ecotec please?

No problems, will do one this week

Very good chav.  thank you.

No problems Will this be moved to the right forum at some point? Oh and is Ash still giving out credits for these Took me hours to write!!!

Requests and submission?

Thanks, now make Trigger do the rest

Very interesting guide.

One question: the stage 2 and up advocates changing to a bigger turbo. Is is possible to add twin turbos to the engine and would this bump up the powever significantly over a single turbo..??

Assuming they can be made to fit, I would ahve though twin turbos would be "better".

The standard turbo is perfect for up to around 300bhp. After that, it cannot flow enough without creating too much heat.

Twin turbos are possible, and if they are of different sizes you can use a smaller one for low-end torque and to help spool the larger one for making boost at higher RPM. Sounds great in theory but in practice it complicates plumbing, causes space and heat issues and requires a lot of calculation to get right. For the money and effort involved you would be better going for a large turbo that spools relatively quickly (ie Garrett GT series). Big turbos are getting better all the time and aren't as laggy as they were a few years back.

That said, Qrew is using a TT setup on his ~700bhp monster Calibra But he is
a) Very rich
b) Crazy

Stick a large FMI on.

What sort of size FMI would be ideal??
Ive been told that if its to large/small it will cause running problems..
Im not smart on this stuff, so im not sure if this is fact..

Seen some on ebay 27in x 7 in x 2.5 with 2.5in ports..

ye mate,im runnig eds phase1,i got front mounted intercooler.since intercooler has gone in,im getting alot off backfire and loss in power.would this be to do with a standard 3bar fuel reg?i got a fsc reg coming,will this cure my problem?

hhmm, the outlined 'Stage 2, 250-300bhp' using vmax evo5 chips needs a little tweaking.

Critically, your fuel pump must be uprated. Stock pump cant take the pressure...literally. particularly 10+ year stock pump on 10+ year wiring.
Seperated wastegate 70mm downpipe  essential to achieve best out of those chips.
Intercooler - 10 litres as quoted above? why? Design far more important than volume. I use a lower volume fmic at a higher power level in a very hot environment and have no charge temp problems.
Adjusted actuator? really needs upgrading to cope with the higher boost.

hhmm, the outlined 'Stage 2, 250-300bhp' using vmax evo5 chips needs a little tweaking.

Critically, your fuel pump must be uprated. Stock pump cant take the pressure...literally. particularly 10+ year stock pump on 10+ year wiring.
Seperated wastegate 70mm downpipe  essential to achieve best out of those chips.
Intercooler - 10 litres as quoted above? why? Design far more important than volume. I use a lower volume fmic at a higher power level in a very hot environment and have no charge temp problems.
Adjusted actuator? really needs upgrading to cope with the higher boost.

If you look in the guide I wrote for redline last year, I covered that as part of the 300bhp+ stage of tune, so I agree with you, Chav seems to be missing the fact that some people have problems at this level (for the reasons you mentioned) but I dont think that its worth worrying about too much, he's done a good job of copying over some of the more key bits of information from max-boost and TBH at the end of the day the site itself isnt really perfect so you cant really expect a guide written from it to be either, so I think he has done a reasonable job. I cant see anyone taking this guide totally literally anyway as its very clearly just a quick copy of some of the key stuff from maxboost, which in itself is mainly a collection of articles from elsewhere of little really specific LET relevance, as the person writing it has very limited experience of the LET himself (johna) so im sure most people wouldnt treat it as an ultimate reference anyway and would seek proper expert advice if they werent sure.


Here is the one that I wrote for redline magazine, it was out at about april 2007 IIRC, but I dont know the exact month:
http://www.clubcalibra.com/index.php?topic=14584.0

Indeed, just slightly concerned that the fuel side of things was dismissed so lightly. For the sake of 90 odd quid tis the difference betweening actually achieving the performance or losing your engine.
A key design facet of both EDS & Vmax chips is for 'fuel cooled pistons' (9.1 a/f at full boost...) - the standard LET pump just cannot provide that flowrate, certainly not when pushed at 4.5 to 6 bar depending on injectors.

 "virtually nobody uses a separated wastegate "
and virtually nobody gets the stated 310bhp & torque line either...

He's just going by what he has read I think mate, but yes you are totally correct, so I dont suppose it hurts to mention it.
I reckon based on what ive seen firsthand probably 80% of cars cope ok on a standard pump setup at "normal" (ie standard or mild hybrid k16) evo5 levels of tune (which realistically is about 280bhp for most people), but obviously a 1 in 5 chance of an expensive meltdown isnt ideal when like you say 90 quid can stop it.

Chip I don't think anything you've ever typed hasn't already been said before, by somebody, somewhere. Except maybe that brilliant time you said that Japanese people aren't Asian, lol.

Ive never invented my own word, I just use english ones normally, so yes each one has indeed been said before.
What I actually write about though, is my first hand knowledge and experience not just copied off a website that some bloke wrote mainly by copying off other websites, so in that respect is very different to what you have put here of course.

What on earth are you on about with japanese and asian people? Is this another one of those things where you have followed me around the internet trying desperately to find a mistake ive made in one of the 10s of thousands of mainly technical posts Ive written? If so have the same response as last time cause I cant really be arsed to write you a new one TBH, lol

You really do seem very desperate to try and prove me wrong on just something *anything* purely for the sake of doing so, presumabley cause you are still sore that you get banned from sites for giving bad tech advice whilst I get approached by admin of the same site and asked if i will consider being an official tech adviser for them? (MIG I mean)

Its very sad that just because I point out that there are MASSIVE technical errors in the rubbish you chat because I want to make sure that people dont get misled by your pseudo technical nonsense that you spout without understanding it that you somehow want to "get revenge" by desperately trying to find something *anything* in fact to trry and pull me up on no matter how trivial.
I dont do it to make you look stupid, you make YOURSELF look stupid, my only motivation for correcting you on things is so that others arent misinformed about stuff that will potentially damage their car a great deal.

You really need to just get over it, I know a sh*tload more about cars, and specifically tuning than you do, big deal, that doesnt mean your life is over, just get used to it, as someone who has worked as a technical consultant to car companies, technical writer for various magazines and is 10 years older than you, its pretty inevitable that its going to be the case, so instead of getting so wound up when I give you the benefit of my advice, why not just have the sense to learn from me instead, after all thats partly how I know as much as I do, from listening to others who know far more than me, I still do so even to this day in fact as im privledged enough to count as friends some of the countries most knowledgeable people, and instead of spending my entire life desperate to correct them on some minor technicality (which invariabley you seem to get wrong more often than right anyway ironically) I just learn from them and appreciate them taking the time to tell me stuff.

You two dont half get annoying.
Can you just settle this with violence instead of making the rest of us read through your drivvle,

Yeah it really is annoying!

Chip doesn't have the ability to let things go by the looks of it, always has to come on with a smart-arse-know-it-all answer to most technical threads. 

If you look up, I was only actually responding (mainly defending chav as at least he has tried his best even if his knowledge is obviously a bit lacking) to posts by another user, it wasnt me bringing anything up at all.

This is where I would go for LET tuning advice : http://www.wallaceperformance.co.uk/vehicle_specific.htm

As far as im aware, WP wont do much in the way of giving out free advice, rather unsurprisingly for a business, but they certainly know what they are doing, Russ's mk2 has been an entrant for the last couple of years in the TOTB team that I manage  and is a testament to their talents.

Old thread alert!

But for what chips to go for, eds or vmax ? I want phase2/evo280 level of power, but in doubt what to use.