Throttle Body Conversion.

[krede]

I get the feeling, that poor Anders won't rest until I have posted something about my recent TB conversion.
I was gonna (eventually) But would have liked to wait a bit, and get some better pictures.
Also, though the car is in service , there is still some work left to be done.
And I would have preferred to present you fine gentlemen with a "finished" product, rather then the current "work in progress".

So where to start?.
Well.. as some of you might know, my car was running a set of 40mm Dellorto sidedraughts with an aftermarket manifold, when I bought it.
While I liked the sound, I quickly grew tired of the constant gurgle and banging hissing and spitting.
I had a friend of mine who has more then a fair bit of experience with twin carbs, have a look at them, but I never got them to run as smooth as I wanted.
Also the carbs would suck hot air from the enginebay as I had removed the airbox due to space issues..
After having driven Mr.Diensens car witch has a normal carb and manifold, but a somewhat hotter camshaft then my "s"  spec, I have come to agree with Roy, that sidedraughts are not really necessary.. and in the case of the aftermarket ones.. very impractical for use in a murena due to the acute lack of space.
IF you are going to run them anyway... you need a real "s" manifold or similar, as this will allow the  carbs to clear the fueltank and give proper room for a decent airbox, and cold air inlet.

But.. to be honest I have never liked carbs, and have from the very start wanted fuel injection to be fitted.
I chose to go for TB's instead of a more common "plenum manifold", because the difference in price wasn't that big, the TB MIGHT give a bit more power, I allready had the manifold to fit them, and, If at some point I (god forbid) should be forced to sell the car, I can fit the old carbs and use the TB's for something else.
I also  saw the switch to Injection as the first step to fitting a turbo, though I have recently learned that this might not be legal to do In Dk.. but that is a different issue altogether.

The specifications are as follows :

-Stock 2.2 bottom.

-Stock cylinder head, but with S spec camshaft.

-40mm manifold ported to take a set of 45mm tb's ( I originally intended to use 40mm TB's as well, but these could not be had with the flanges I wanted)

-25mm inlet "air horns" or "bell mouths"

-Distributor from a Peugeot 505 turbo.
I got one of these as they have a build in hall sensor that can be used by the ECU instead of having to fit a timing ring to the crank, as space Is limited,its a lot of work, and they can cause a lot of agony and grief if not set up just right.
At first I wanted to go on with a distributor ignition system, since this was the simplest solution. Also distributor-less ignition required, a better signal then the Hall sensor in the 505 Distributor could deliver.
However, during the installation it was discovered that the Murena coil was in bad shape.. and it was decided to have a go at modifying the Distributor with some opel parts, to allow a distributor-less system after all.

- Thermostat housing from a 505 turbo.
The standard Murena can easily be modified as well, but with the 505 it was a matter of plugh & play.. (plugh plugh plugh and play actually as it has a tremendous amount of fitting points for sensors, pipes , hoses etc etc)

- Home made "in tank " fuel pump assembly. using an EFI pump from a ford escort cosworth.
This is still an "experiment" and I want to see how well it works before deciding if improvement of the design is needed.
As of now I haven't fitted the fuel gauge sender, so I'm running "bingo fuel" all the time.... no big deal though as I just refuel every 300 km as I have always done. Btw It now on 95 unleaded... easier to come by.. but it doesn't smell HALF as nice as true 98  

- Wolf3D v4 Programmable enginemanagement system.
I found a nice spot for the ECU above the glove compartment behind the dash, but had to lengthen ALL the wires, as I didn't dare to fit it in the boot due to heat.
 

The system is set up to use input from water/air temperature, Hall sensor and TPS sensor.
No lambda or map sensor was needed.. though I thought I would need both.
     
The first agreement was that no more time then necessary would be spend on the "artistic" impression as I can fit the wires and stuff myself.
All the guys at the shop should worry about was getting it to work, and setting up the ECU on the rolling road.
As a result I had to drive half way across Denmark with an enginebay looking like this:



The new ignition amplifier had been fitted the same place as the original one (or at least where it was in my car... right had side, under the vacuum bottle)
However it had been fitted with the wires turning UP, and the two unused terminals left UNPLUGGED (you can see where this is headed).
Much to my surprise the spot chosen for the amplifier is NOT a safe or "dry" spot... .. so.. about 45 minutes into the journey home, as I was switching lanes and hitting a pool of water on the road.... a wave drenched my ignition amplifier....my ENTIRE ignition amplifier.. and NOTHING but my ignition amplifier!!
The open terminals in the socket let in the water very nicely, and the way the amplifier was mounted meant that what ever water DID go into the socket STAYED in the socket!!
I was saved from complete embarrassment, only because the amplifier had been mounted with a slight angle, keeping a couple of the terminals above water... leaving me 2 working cylinders to reach the nearest motorway exit and limp to a parkinglot!!.
However ½ an hour, and 2 phonecalls later, I was on my way again.Luckily nothing got fried.
I have since fitted the amplifier the RIGHT way up...a "safer" place, and plugged the unused terminals.. and have not have any problems with it since.

The car now runs MUCH more smooth, with no banging or spitting what so ever.
Throttle response has picked up considerably, and Idle (once the alternator has kicked in) is a real peach compared to before.


Its a crappy clip.. but it was late, and I had been at it in the engine bay for 11 hours straight with only tea and biscuits for substance. 


The power:


As you can see its a small gain over a carburetted "s", but no rocket ship.
In fact I am a little disappointed.. Not that I expected much more really, but 145 hp doesn't fell like much in a Murena, and you never get any real sense of acceleration. 
One thing though...
This graph is with only 2.5cm air horns bolted straight on the TB's.
My fist plan was to fit a home made airbox with the airhorns inside, straight to the TB's... This is possible as the TB's are actually a few centimetres shorter then the Dellortos they replace.. leaving roughly 7cm of clearance between the TB mouths and the fueltank.
The guy who programmed my ECU said that this car could really benefit from some longer inlet ducts.
Also.. since I found it IMPOSSIBLE to get my paws inside my home made airbox to fit the airhorns, I decided on a different solution:



These will bolt on to the TB's in such a way that the airbox(a new and IMPROVED model I will have to make) will be right over the TB's themselves.
Hopefully the longer inlet should move the power further down the rev range, and improve the torque.(though the car needs to go on the rolling road again to have it set up... but it is a quick job)

I just got these pipes today, so I cant tell if they are any good, or show you any pictures of them fitted on the car... as I said ... work in progress.....

more to follow.

Krede

 
 




 

   

[Bart_Maztra]

WOH impressive.
Which throttle body's did you use? I need those aswell.

[krede]

Dbilas...they are ok, but nothing special.
But a friend of mine has just bought a set of Jenveys .. they are more expensive... but I'd cough up the extra money if I had to buy another set.

[Anders Dinsen]

I get the feeling, that poor Anders won't rest until I have posted something about my recent TB conversion.

Well thought... I could finally sleep after reading your post!!

Your airbox pipes look very good congrats on them.

Cheers,
Anders





 

   
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[michaltalbot]

Hm, as I am not a big friend of all matra conversions, THIS seems to be VERY interesting to me! Krede, hats off  I'm really wondering about final results from your project - power, torque, acceleration, top speed and price of all.

[krede]

Well I really dont want to think about the price, as it has already become much more expensive then I expected....but from my experience that's true to most everything when it comes to cars... it always end up costing more then you ever thought it would. ...

Another couple of pictures showing the inlet pipes.. I test fitted them today.. :


They are stainless though they dont look like it... I will see if I can polish them up a bit.

My plan is to fit an aluminium backplate behind the airhorns, and then build an airbox (possibly from fiberglas) and connect it to the standard airfilter box.
On this lower picture you can also spot the "repositioned" Ignition module/amplifier in the top center, and the two Ignition coils. (its running a "wasted spark" setup).
The Spark plugh leads,has been bought from Bosch, and is supposed to fit a 505 turbo(as it has the same layout as the murena).
But surely two of the leads would NEVER have been able to reach the distributor.!

[Anders Dinsen]

The pipes look very good on the TB's I think. It looks like the dip stick is in risk of being covered under the airbox.
What is the vacuum hose that interconnects the TB's for?

[krede]

There is at least 15 cm for an airbox.... thats plenty.

The hoses is just a fancy way of plugging the vacuum pipes.
It kept "shooting " the blinds that came with the TB's off resulting in poor idling.. so I made this instead.

[Megatech]

This is indeed an interesting project. Please keep us updated frequently.
I am a little dissapointed about the output you have gained so far. It is no better than a good 142s, and you only gain extra power above 6500 rpm - which hardly is usable. Compared to Politecnic 180 HP and 190 Nm should be the target.
I have planed this change also, but lack of courage and time have stopped me so far. I have purchased TB 45's with injectors, TPS and linkage, a Lumenition brain with W.loom. What I need is fuel pump, pressure regulator and catch tank - and an experienced person to guide me through the installation and programming.

Does anyone have experience with the Politecnic-TB-conversion?

[krede]

It is no better than a good 142s

Indeed it isn't..
that said.. it is more or less the same "hardware", only the venturies are replaced with injectors... the rest of the engine is exactly the same.
Once programmed, my ECU is pretty much as "blind" as a carb setup , as it doesn't measure the the fuel/air mixture or air mass/flow, as virtually all injection systems does.
The only improvements are, doing away with the distributor for more reliable ignition system, and the ECU's ability to make adjustments according to the air and water temperatures. (things that has little effect once the engine is hot) 
As you very correctly mention, the advantage of TB's (and twin carbs aswell ) is better "breathing" of the engine.... and this only has any effect at the top of the rev-band.´, and in combination with other engine modifications.
But... for an engine having done 150000+km... with a burned out exhaust silencer (though be it with a never cylinder head) Id say that its a good job to gain anything on a factory "S"

My best bet for more power, would be to have the head ported for better all round airflow(I doubt that there is space for larger valves? ).
Next step would be to have, light weight pistons and conrods fitted.. and maybe stiffer valvesprings (if necessary?.. I have read that the standard ones will take the engine to 7000rpm before giving up?)
And finally a hotter cam.. though here there is a trade off to consider as fitting too hot a cam will make the car unbearable in daily use.

If these mods are done properly, THEN the engine will benefit from having the TB's/twin carbs fitted.. otherwise its mostly the noise you gain.(and decreased fuel milage)
One final benefit of the multi throttleplate setup though...is that you can secure an "equal" flow to each cylinder...  hard to do with a standard plenum type manifold

I'm pretty sure that the politechnic kit is a somewhat "hardcore" solution, mostly minded on motorsport.
I seriously doubt that it is possible to get 180hp from the Murena 2.2 engine without spending some serious money and time on it, and making it unfit for everyday use.
190nm however should be within reach.

I considered a "catch tank" as well , but opted to go for an "pump in tank" design for 4 reasons.
First, it saves one fuel pump, leaving less things to go wrong, and keeping the wiring simple.
Second to save space in the engine room.
Third reason was the price and inconvenience of having a custom catchtank build.
And finally... unless mounted low, a catchtank holding 1 or 2 liters of fuel, will get hot in the enginebay of a murena, and hot fuel really hurts performance (I have been told)
I have ordered an even smaller EFI fuel filter, that will go into the tank with the pump, and thus leaving only the fuel hoses in the enginebay itself... It will be a little more work to service, but I can live with that. 

My advice if you want throttlebodies fitted, is to go to the workshop you want to do the work of installing/running in your system, and talk to them about the what parts you need ,and how to fit them(if you want to do some of the work yourself)
This will save you a a lot of headache, and avoid you ending up buying stuff you dont really need.

[Anders Dinsen]

6500 rpm - which hardly is usable. Compared to Politecnic 180 HP and 190 Nm should be the target.

I don't think Politecnic is getting 180 BHP from the standard S-cam and unmodified head, they are probably running something a good deal more aggressive, and as Krede points out - not suitable for the road...

Once programmed, my ECU is pretty much as "blind" as a carb setup , as it doesn't measure the the fuel/air mixture or air mass/flow, as virtually all injection systems does.

TB injection systems can't really rely on air flow meters or manifold vacuum measurements as it's pulsating far too much, especially on hot cams with large overlap - so it is quite common on EFi systems like yours to run "open loop" using only the throttle position sensor in combination with the RPM and knowledge of the engine's Ve over the rev-band to determine how much fuel is needed per stroke.

[krede]

Right... time for an update...

I had the ECU out, and send to Australia for a firmware update ,while I was in Kosovo, but something went wrong, and the "new" software didn't take to kind to having installed an engine map made with the "old" software...
As such, it messed up the LOAD curve to such an extend that it thought it was under foll load from 25% throttle and up!!.. Leaving me with an engine struggling to keep up with the massive amounts of fuel being forced upon it!...
This left me with some very charred spark plugs, and a dreadful fuel economy (about 5 km/l)

As I was going to have the longer inlet runners fitted anyway, I parked the car (for 3 WEEKS!!!) and went by bicycle until i could get both things fixed at the same time.
That time was this Tuesday, and I picked up the car yesterday.

Here is the result.


As you can see the power and torque is up right up until the high end of the revband. a 16nm increase is pretty good I'd say.. and something to think about for people who has to choose a set of inlet runners/trumpets for a similar setup... this engine likes long inlet runners..
That the power is down 6 hp is NOT solely a result of the longer inlet runners, as the old power curve was made with the engine running on 97 octane fuel, while it is now on 95 unleaded.
Cost me 2-3 degrees of ignition advance if I recall correctly...   

i fitted an airbox and a new oem replacement 2.2 exhaust while I was at it... though stainless exhausts might not corrode.. they can still burn out.. and burn through!.


The bad news is, that the brutal inlet roar has now been muffled quite a bit... it still has a nice grow, but NOTHING like before...

[Waldo]

Hi Krede,

Very nice job indeed... great to see someone also working on improving the drivetrain!

I got the impression you are having 2nd thoughts concerning the turbo installation.
What information have you recieved regarding this?

I'm aware that fitting a turbo charger is thought of as a construction change and more than 20% power increase by the danish MOT/TÜV.
Therefore you will need to talk with the danish tax people to get new registration papers... also you must document that the car can handle the extra power! (like the situation Jesper is in)

I'm asking as I would like to know if there's anything you have been told, that would give me a problem with my HDI 

I have a clear from the tax department that they don't wan't more money from me, and as I have documentation that the "new" engine is also producing 90bhp I hope there is no problem 

[Anders Dinsen]

Congrats on the improvement!

You won't notice the difference in power on the top band in street use, and the torque number is excellent. As you say: Long runners does wonders for torque.

But I don't agree that the ignition is to blame for the lower power output - it's the runners again, and your airbox. You will notice that the torque curve starts dropping at around 5500 rpm. Air management is the only thing that can improve that.

Go get your head polished!

[krede]

Go get your head polished!

Waste of money...
Though a good "head job" can work wonders (especially on older heads), my installation is far too "crude" for it to have any effect!
Cylinderhead mods MUST be matched with the rest of the parts used, and mine are mostly some half hearted "home cooking"..
But... if done right I have no doubt that 170hk on n/a would be in reach... but it would be far more expensive then fitting a turbo.

I got the impression you are having 2nd thoughts concerning the turbo installation.

If anything I am even MORE inclined to go ahead with the turbo build, after I have had the Throttlebodies fitted.!!
It is clear to me, that my murena will never be the car I want it to be without a turbo.
IMHO the 2.2 is a poor engine, and serious tuning options are few, and expensive.
 I think the fact that Matra never intended to use this engine in the first place, proves my point.

However...
If production had continued I'm pretty sure Matra would have fitted the peugeot n9t engine in it.. or at least offered it as an option, since it is a perfect fit!.

I'm aware that fitting a turbo charger is thought of as a construction change and more than 20% power increase by the danish MOT/TÜV.
Therefore you will need to talk with the danish tax people to get new registration papers... also you must document that the car can handle the extra power! (like the situation Jesper is in)

If you have to be brutally honest.. SO IS FITTING A SET OF THROTTLE BODIES!!.. though it is less obvious, if you read the legislation carefully you would also in theory have to pass emissions and noise tests AND provide documentation for the new power output!

As for the Turbo, I have investigated what is possible and what isn't.
In my case I'm in luck.
My car is a standard 2.2.. that has been taxed and registered as having the same power as an "S".. (142hk.).
This is more then an 20% increase in power...and as such is a construction change.. But since the rest of the car is 100% mechanically identical to the more powerful "s" Murena, it isnt a problem.
As you know you are always allowed to increase the power of a car up tp 20% without having to provide any documentation, pay extra tax etc etc...
Now... a turbo is always regarded as a power increase of more then 20% BUT!
My car already HAS a power increase of more then 20% in being approved with 142 hk.
So I am allowed to fit a turbo to the original 118hk engine, and increase the power up to 170hk (20% above the 142hk).
In Denmark 170hk is the ABSOLUTE limit a Murena can be approved with, without providing some sort of documentation..... documentation that can only be obtained by undergoing expensive Tüv tests.. (and even Tüv say that if you increase the power by more then 20% the tests will be much more rigorous)
The 20% rule regarding turbo charging also mean that you CANNOT
one to a Murena "S"!!..as this would automatically be regarded as more then 170hk!.. EVEN if you swap the engine for a standard 118hk first!!!