Paul Mcgill

Hi all i have a 2.0 dohc efi sierra and i would like to put a turbo on it its no my daily driver just a classic used at weekends iv been doing alot of research and just havent been able to find anyone to help

i no turbo technics used to build a kit but no longer do so i would just like to make my own
I have the basic idea with manifold turbo intercooler and pipeing just cant get my head around the fueling and mapping side of it

iv heard alot o people using a 5th injector and upgraded map sensor and others using a aftermarket ecu and getting it mapped
anyone have any idea help much aprechianted

JFB Tech

The standard ECU can't handle a boost signal from the MAP sensor. The sensor is a frequency rather than voltage type. As the ECU isn't expecting to see a boost signal, it goes into Limited Operating Strategy, fixing the ignition timing and injector pulse length as a "get you home" fix. This will result in a very lean mixture on boost as well as completely the wrong ignition advance, resulting in head, head gasket and piston damage due to severe detonation. Turbo Technics got round this by fitting an electronic frequency limiter to the MAP sensor wiring so that the ECU never saw the boost signal. They also used a digital control unit to fire a 5th injector when on boost (using the coil pulse signal and the voltage from an additional MAP sensor to determine injector pulse width requirement). To manage the ignition timing, they simply shorted both of the ignition timing adjust pins in the octane adjust plug to ground.

I used to run a DOHC with the Turbo Technics kit on it. It made 174 bhp at the flywheel running through a Scorpion stainless exhaust.

Paul Mcgill

Hi thanks for the reply do u no its there a way the replicate the that or do u no were i could get the bits i need

Paul Mcgill

Like can u buy the 5th injector setup and the map sensor frequance controler

oldford

Or use an aftermarket programmable ecu. Then you have complete control over fueling and ignition timing.
It won't be cheap as you will probably need a wiring loom, some sensors and 4 bigger injectors also.

Paul Mcgill

And by going down this route dose this mean i dont need to fool the map sensor? Do u have any recomendations to a aftermarker ecu? Or what do u think is my best opption another lad from another form has a diy kit that he made up few years ago using a 5th injector for fueling but he didnt menshion anything bot the frequency limiter or if he dosent have one could i just use a 2bar map sensor from a cosworth and ground the timimg pins myself

oldford

You can use a 2 bar map sensor from a Weber-Marelli (if still available) or any other major manufacturer (like Bosch) that produces a 0-5V signal (most of them do) in combination with a aftermarket programmable ecu. I would strongly recommend you to use one in this case.
In this case you also don't need to fool the original map sensor as you would not be using it at all.
In this case you have complete control over ignition timing also means different timing for different loads.
You don't have to retard the ignition moment very much for only 0.1 bar of boost, whereas you would retard it more for say 0.7 bar of boost.
So, ther'es absolute no need for grounding the timing pins on the ecu.
The same goes for fueling, you would have complete control over fueling with all possible loads.
So, with bigger injectors you don't need the 5th injector.

You cannot use any 2 bar map sensor in combination with the original ecu, because this will cause under fueling over the complete range, including off boost driving. Not to mention that you cannot use the Cosworth 2 bar map sensor or any other map sensor with a 0-5 volt signal in combination with the original ecu because the ecu would not recognize it's signal at all.
Grounding the timing pins on the original ecu is ONLY done when driving on boost, otherwise you would ruin the fuel economy off boost and also loose power when driving off boost. So, you cannot permanently ground these timing pins. That's what they use the 2nd map sensor for.

With a aftermarket ecu you can also control the turbo boost if you would like to and various other things like cooling fans.
These capabilities have a positive effect on safety and durability of the engine.

You are probably not capable of programming the aftermarket ecu yourself.
So, I would suggest use the one the tuner that will do the mapping recommends.

Paul Mcgill

Perfect so basicly make up a turbo kit use my standard map sensor and bigger injectors and get a aftermarket ecu and get it all mapped to suit? Have u any idea what the best ecu to use would b?

oldford

NO, you CANNOT use your standard map sensor.
First of all because it is NOT capable of measuring turbo boost, it's only capable of measuring pressure up to atmospheric pressure and not above.
Secondly because the signal is a frequency signal that aftermarket may not understand.

Paul Mcgill

Ok so upgrade the map senson to the one u said in your last post and that combined with the new ecu and a remap will work

oldford

Yes, provided this ecu can cope with the standard coolant and intake air temperature sensors.
But don't forget the injectors and that you probably will need a new wiring loom.
Especially if you want turbo boost control or coolant fan control or anything else that is not present on the standard ecu.
You will also need a valve for the turbo boost control.

First select a tuner somewhere nearby, then find out what he recommends.
Or select a system yourself (with all possible risk of mistakes) and end up with a tuner a few hundred miles away.
Sometimes you may need a new fuel pump as well, depending on how much the standard fuel pump will flow and how much the engine will need.

costina

iTrader: (1)

Why not find a 2.3 16 valve mk3 scorpio and use all that in the sierra. Then turbo that.

Caddyshack

Paul Mcgill

I have found a lad that has a homemade version of the turbo techics kit custom manifold and turbo cossie rad and intercooler and a 5th injector set up that ran off map sensor he said he had it running perfect at low boost abot 5psi only prob he had was a slight hesatation on half throttel when boost kicked it
but that it ran fine for ages until he upped the boost to much abot 15psi and it blew after a few months im lookn at getting this kit off him do u no do i need anything else to go along with it ie. Retard the timing or frequancy limiter and if so where can they b bot

JFB Tech

If you are running the standard ECU and MAP sensor then you will HAVE to have the frequency limiter. I know the frequency limiters are not available any more but I am looking into making them myself. I made a copy of the Turbo Technics 5th injector controller as mine died. Turbo Technics had the octane adjust pins grounded continuously but I found that it works a lot better if they are shorted through an adjustable vacuum switch. You set it so that it only grounds the pins when the inlet vacuum doesn't exist any more (i.e. you're coming on boost). This way you don't loose any of the off boost performance.

Paul Mcgill

Ok cool and when do u think ul have to frequancy limiter and retarded timing switches

JFB Tech

I have the enquiry regarding the frequency limiter circuitry in place and can look out the details I have for the vacuum switch I used. Not sure how long the enquiry will take, or sourcing the components.

Paul Mcgill

Can u keep me informd as id b very intrested

stevieturbo

The best ecu is the one you can get local support for and a competent tuner !

So the best isnt always the best.....as it requires more than just the ecu. And of course your budget will dictate a lot.

Isnt there some tuners in Galway ? Couture or something ?

Robert in Powermax in Cookstown has run a couple of DOHC turbos for many years now, so might be worth a shout

serg1ortega

Sorry for the up
I am adapting a Mercedes SLK supercharger to my Sierra Dohc and I am trying to delay the ignition by taking the two octane adjustment pins to ground but I do not notice that it delays the advance, I am measuring it with a strobe lamp and I do not notice anything.
(My idea is to use an Arduino to connect those pins to ground when it goes over 0.15 bars and activate a 5th injector, more or less like turbotechniks did)
What I can be doing wrong? I am joining the two wires (brown/blue and brown/red from the 3-pin connector that are next to the coil) to each other and then to ground.
Thanks in advance! And sorry for my low level of English