General Fiat Stilo Abarth 2.4L 20v Turbo!

[D4nny8oy]

I'm not trying to rip the p***, it's just that you see so many people who've read a few Max Power magazines and think they can build/do anything.

If it all works out ok, then respect where it's due- I converted my XR3i to an RS Turbo despite many telling me it wasn't worth it, especially spending about a year collecting various parts, checking wiring diagrams and so on.

A wastegate controls the speed of the turbo (and therefore the boost). When the preset pressure is reached, say 15psi/1 bar, the diaphragm in the actuator overcomes the spring holding the wastegate closed and opens it, allowing exhaust gases to bypass the turbine wheel thus preventing the turbo from speeding-up further.
A controlling solenoid can be used to manage the actuator electronically- making it hold maximum boost right to the red-line, or gently tail-off to prevent the risk of leaning-out, or 'bleed' the boost in gently to cut down on wheelspin. It can also be used to provide a short period of extra power for overtaking ('Overboost'- like in modern JTD's).

It's possible to run without a solenoid, plumbing the actuator straight into the compressor side of the turbo (I ran my RS like this for 2 years at 20psi, I only went over to a boost controller recently for more stability), only problem is it would probably leave the management lamp on, and maybe run in "Limp mode".

A dump valve is different altogether. When the throttle is wide open, the 15psi is flowing through easily no problem. When the throttle is then snapped shut (for a gear change) the pressurized air is now up against a wall (throttle butterfly) and backs-up until it ends up going backwards through the compressor vanes, this creates a 'chatter' sound as the blades 'chop up' the air and can cause the turbo to stall, creating lag when the throttle is reopened. A dump valve can be used to help relieve the pressure. They can be atmospheric- where the boost is released to the outside air, or recirculating- where the boost is directed through a pipe back into the inlet side of the turbo, where it loops around without disrupting the compressor wheel.

Many, including yourself I'm guessing, regard the atmospheric version as a little 'chavvy'. I'm certain Coupe's had the recirculating system as standard so you could use this, though some creative plumbing would be needed for a Stilo.
Or you could forget the dump valve, and enjoy some 'chatter'.:devil:
It shouldn't cause problems unless you're running high boost or a roller-bearing turbo.

Incidently, what ECU are you going to be using? I wouldn't think the standard Stilo ECU and MAP sensor can handle positive (boost) pressure as there's no need to in standard N/A trim. And I'm almost certain the Coupe ECU wouldn't be compatible with the CAN network, causing multiple errors.

Have you made sure it all fits in the engine bay?- there's not a lot of room for the standard manifold/Cat assembly from memory.

Let us all know how it goes.

 

[Dax]

I'm not trying to rip the p***, it's just that you see so many people who've read a few Max Power magazines and think they can build/do anything.

If it all works out ok, then respect where it's due- I converted my XR3i to an RS Turbo despite many telling me it wasn't worth it, especially spending about a year collecting various parts, checking wiring diagrams and so on.

A wastegate controls the speed of the turbo (and therefore the boost). When the preset pressure is reached, say 15psi/1 bar, the diaphragm in the actuator overcomes the spring holding the wastegate closed and opens it, allowing exhaust gases to bypass the turbine wheel thus preventing the turbo from speeding-up further.
A controlling solenoid can be used to manage the actuator electronically- making it hold maximum boost right to the red-line, or gently tail-off to prevent the risk of leaning-out, or 'bleed' the boost in gently to cut down on wheelspin. It can also be used to provide a short period of extra power for overtaking ('Overboost'- like in modern JTD's).

It's possible to run without a solenoid, plumbing the actuator straight into the compressor side of the turbo (I ran my RS like this for 2 years at 20psi, I only went over to a boost controller recently for more stability), only problem is it would probably leave the management lamp on, and maybe run in "Limp mode".

A dump valve is different altogether. When the throttle is wide open, the 15psi is flowing through easily no problem. When the throttle is then snapped shut (for a gear change) the pressurized air is now up against a wall (throttle butterfly) and backs-up until it ends up going backwards through the compressor vanes, this creates a 'chatter' sound as the blades 'chop up' the air and can cause the turbo to stall, creating lag when the throttle is reopened. A dump valve can be used to help relieve the pressure. They can be atmospheric- where the boost is released to the outside air, or recirculating- where the boost is directed through a pipe back into the inlet side of the turbo, where it loops around without disrupting the compressor wheel.

Many, including yourself I'm guessing, regard the atmospheric version as a little 'chavvy'. I'm certain Coupe's had the recirculating system as standard so you could use this, though some creative plumbing would be needed for a Stilo.
Or you could forget the dump valve, and enjoy some 'chatter'.:devil:
It shouldn't cause problems unless you're running high boost or a roller-bearing turbo.

Incidently, what ECU are you going to be using? I wouldn't think the standard Stilo ECU and MAP sensor can handle positive (boost) pressure as there's no need to in standard N/A trim. And I'm almost certain the Coupe ECU wouldn't be compatible with the CAN network, causing multiple errors.

Have you made sure it all fits in the engine bay?- there's not a lot of room for the standard manifold/Cat assembly from memory.

Let us all know how it goes.

That's more like it, I will have to look at a coupe engine compartment to familiarise myself with the whole issue of pressure relief! I can only find the electric solenoid in the parts diagrams?
The turbo is just the standard T28 that's fitted to the Coupe, I'm not looking for 400BHP, I just want the 220BHP factory setup. I've contacted a company with regards to having a 'piggy-back' ECU fitted for the turbo.

I've done a dry fix of all the components and the only alterations so far have been altering the radiator fan to enable the turbo to fit, which is pretty easy and looks like an OEM part, drilled an oil pick-up in the block, which is already there and threaded, just needed completely drilling through, removing the existing water cooled oil cooler and pipes and replacing it with the Coupe air cooled one, replacing the thermostat housing with the Coupe one and blanking one of the sensor holes off, replacing the nearside inner plastic wheel arch with the Stilo diesel one as it allows the inter-cooler pipe to pass through, installed an inter-cooler on the nearside wheel arch, quite straight forward as its ready to accept one due to the Stilo diesel has one there, used a Coupe factory down pipe and altered it to meet the rest of the exhaust system, there are two cats on the 2.4, so I removed the first one which bolts to the exhaust manifold, I did buy an aftermarket down-pipe, which was half the price of an OEM one, but was poorly built and hit on the AC pump pipes, replaced the sump for a Coupe one, this is an expensive way just for an oil pick-up as the Stilo has the casting there, just needs drilling, threaded and a pipe end screwed in. However, you cannot buy this pipe end from Fiats separately, so I had no idea what it looked like, so I bought a complete sump.

I've also contacted a couple of companies today for prices of forged pistons and con-rods, they seem to range from £1000 - £1500 for a set, lot of money, but I bought this car new and it's not worth much now secondhand, so rather than buy another car and loose another load of money, I might as well spend it on this one, at least I will have something to show for it!

Just one other issue, do you think there will any issues with this having the selespeed gearbox?

 

[h2ypr]

I have asked about 2.4 forged pistons. Pm me for details.

Ross

 

[D4nny8oy]

The selespeed 'box is a standard box as used in the Alfa petrol engines (1.6/1.8/2.0 T Spark) and Fiat 1.8 petrol and 1.9 JTD engines, albeit with an automatic selection system bolted-on. The internals should be as strong as any other of these boxes in the ranges above.

The fact that it's been used in the JTD's for so long without serious issues suggests it should be ok coping with loads of torque!

Regarding PNL's comments on the suspension- I believe what he's questioning is not whether the shocks/springs can handle the power, but if the wishbone bushes can- remember they've got a lot of work to do, and now you're putting another 50bhp through them. I'd be thinking about maybe fitting poly bushes (if available- dunno about the details of suspension tuning on Fiats ) at the very least.

 

[dan-the-man]

you could probably reach 220bhp from a decent induction, exhaust, sports cat and a remap. Or not be far off.

The selespeed gearbox should be able to handle that amount of power

 

[J333EVO]

Really nice project, like it, like it lots.

TBH if you have already lowered the compression on the car and plan on running fairly low boost levels as the power gains you are after are modest from a turbo set up, so say up to 1bar (14.4PSi) then I believe in all honesty that the crank/rods/pistons will be fine, as if they were not built to be able to take an extra 50bhp there would be many many cars in scrap yards now broken as the tolerances would have been so low even standard cars would have gone by now, all car components are over engineered to cover many miles/driving styles, BUT how did you lower the compression?

As for solenoid, don't bother trying to replicate factory set up, you have the turbo and the waste gate which are mechanical, so if you need to control boost further than the waste gate does already then fit an after market boost controller from the likes of TurboSmart, Greddy as they are all better than the factory stuff on Coupe's, and in case of the turbosmart controller fits inside a standard gauge aperture and doubles up as boost gauge so can be made to look factory if you have a suitable place to put it.

You didn't say which piggy back you were using, but a good one that can work on cars that have been boosted is the Dastek Unichip, it's the piggy back of choice on Supercharged Suzuki Ignis's and Turbo/supercharged Saxo's etc has its own inbuilt MAP sensor and can control fuelling and I think, it has other functions as well.

Some good info on what items do, for instance older turbo cars like Renault 5GTT's did not have any form of electronic boost controller it was all done with the wastegate settings.

Some older turbo cars did not even have a dump valve, but most modern, Audi/VW 1.8 20VT, integrale etc all use a Bosch plastic recirculating dumpvalve which many change to atmospheric.

As for suspension, get it running first any weakness' will soon become apparent and then you can work on them.

 

[Dax]

Really nice project, like it, like it lots.

TBH if you have already lowered the compression on the car and plan on running fairly low boost levels as the power gains you are after are modest from a turbo set up, so say up to 1bar (14.4PSi) then I believe in all honesty that the crank/rods/pistons will be fine, as if they were not built to be able to take an extra 50bhp there would be many many cars in scrap yards now broken as the tolerances would have been so low even standard cars would have gone by now, all car components are over engineered to cover many miles/driving styles, BUT how did you lower the compression?

As for solenoid, don't bother trying to replicate factory set up, you have the turbo and the waste gate which are mechanical, so if you need to control boost further than the waste gate does already then fit an after market boost controller from the likes of TurboSmart, Greddy as they are all better than the factory stuff on Coupe's, and in case of the turbosmart controller fits inside a standard gauge aperture and doubles up as boost gauge so can be made to look factory if you have a suitable place to put it.

You didn't say which piggy back you were using, but a good one that can work on cars that have been boosted is the Dastek Unichip, it's the piggy back of choice on Supercharged Suzuki Ignis's and Turbo/supercharged Saxo's etc has its own inbuilt MAP sensor and can control fuelling and I think, it has other functions as well.

Some good info on what items do, for instance older turbo cars like Renault 5GTT's did not have any form of electronic boost controller it was all done with the wastegate settings.

Some older turbo cars did not even have a dump valve, but most modern, Audi/VW 1.8 20VT, integrale etc all use a Bosch plastic recirculating dumpvalve which many change to atmospheric.

As for suspension, get it running first any weakness' will soon become apparent and then you can work on them.

Lowered the compression ratio with an 2mm aluminium spacer made to order from Ferriday Engineering in Stafford. Really good web site and really pleasant people to deal with. Could have used the thick steel Coupe Turbo one, but I think this would have only brought it down to 9.5:1? The aluminium one brings it down to 8.3:1.

 

[Dax]

Just ordered forged pistons and con-rods, which actually reduce the compression ratio to 8.5:1, so after spending £150.00 on this decompression spacer, I now no longer need it!, anyone one to buy it for an Abarth Turbo conversion!!

Also ordered the Turbosmart dual boost controller as recommended to overcome the factory solenoid issue.

Just a couple of pictures if anyone is interested?

http://i35.photobucket.com/albums/d171/parkermiles/IMG_2423.jpg
http://i35.photobucket.com/albums/d171/parkermiles/IMG_2422.jpg

 

[h2ypr]

At no point did I suggest that he doesn't know what he is doing. I am in contact with him and owe him a pint. He does a good job an what he is taking on and he definitively is oldschool.

Your qoute was:

...He might also be able to offer some real world advice on your project...

I am only for over 25 years in the tuning business and some others here have a lot of tuning and engineering expertise too. Your comments suggest that we are idiots who do not know what we are talking about.

I would also say that Guy Crofts knowledge is not in question. However, there are people that know more about an individual engine or setup.

Ross

 

[thepottleflump]

Trouble with forums, and any form of written text is all too easy to misinterept; I obviously wasn't careful enough in the way I phrased my comment. My main suggest was ask him about Forged Pistons and then he might also be able to tell the chap if he'd also had any experience himself doing something similar with one of these engines too. Was no way meant to berate or take away from any of the other posters on this thread and you've obviously got a great deal of experience tuning. Sounds like an interesting project, wish I had the time and experience to undertake something like this.

 

[Oldschool]

Trouble with forums, and any form of written text is all too easy to misinterept; I obviously wasn't careful enough in the way I phrased my comment. My main suggest was ask him about Forged Pistons and then he might also be able to tell the chap if he'd also had any experience himself doing something similar with one of these engines too. Was no way meant to berate or take away from any of the other posters on this thread and you've obviously got a great deal of experience tuning. Sounds like an interesting project, wish I had the time and experience to undertake something like this.

Misunderstanding cleared. No hard feelings.

It is an interesting project and I wish him well with it. Unfortunately Fiat have cut corners on the quality on the original engine.

We are looking into this engine for quite some while and I am rather angry with the Fiat management to use such a brilliant concept to save money rather than to give Fiat back what it used to be.

Most important is to sort out the float, which is the reason why a number of the 2.4 blew even in standard configuration.

 

[Dax]

Misunderstanding cleared. No hard feelings.

It is an interesting project and I wish him well with it. Unfortunately Fiat have cut corners on the quality on the original engine.

We are looking into this engine for quite some while and I am rather angry with the Fiat management to use such a brilliant concept to save money rather than to give Fiat back what it used to be.

Most important is to sort out the float, which is the reason why a number of the 2.4 blew even in standard configuration.

I understand crankshaft float as the measurement taken at the thrust washers, is this correct? If not could you explain and do you have any ideas?

 

[Oldschool]

I understand crankshaft float as the measurement taken at the thrust washers, is this correct? If not could you explain and do you have any ideas?

Yes and the same problem is with the conrods.

As the modifications we are looking at meant to be for more than just one engine we heve not finished the job, which will take some more time.

 

[sediciRich]

Speak to Guy Croft if you're after fordged pistons & conrods for a Fiat. He might also be able to offer some real world advice on your project http://www.guy-croft.com/

Thank you for branding us idiots.

Reading this for the first time seems a slightly odd, perhaps brash reply, it took another page before I got an idea of why you replied in such a way. Still a little unjustified in my view.

Good luck with the 2.4 turbo. Personally if you want to do it properly and with potential I would budget for a proper mappable ecu. Of course there are alternatives to this cheaper, but certainly not as good.

As for the chassis, I would imagine its far superior to a chassis designed in the mid eighties on computers the size of a room.

Rich

 

[Dax]

Reading this for the first time seems a slightly odd, perhaps brash reply, it took another page before I got an idea of why you replied in such a way. Still a little unjustified in my view.

Good luck with the 2.4 turbo. Personally if you want to do it properly and with potential I would budget for a proper mappable ecu. Of course there are alternatives to this cheaper, but certainly not as good.

As for the chassis, I would imagine its far superior to a chassis designed in the mid eighties on computers the size of a room.

Rich

Thanks and it will be completed no matter what it costs me!! looked at your link for your vehicle and you seem to have completed it to a quality standard.

Where would one get such an ECU and who would do the remap, obviously not something I can do myself!

 

[jug]

As for the chassis, I would imagine its far superior to a chassis designed in the mid eighties on computers the size of a room.

hahaha, you've obviously never driven a stilo
the tipo chassis is far more capable.

 

[sediciRich]

True jug, but I cant imagine how it can be as poor as the tipo floor pan. If you look at each incarnation of the mitsubishi lancer they find whopping percentage rigidty increases in torsional rigity every release. <ust be down to improve FEA. Since computing power is so much greater between model's develpment periods I cant imagine a regression in design objectives??

Rich

 

[jug]

i agree, but it happened with the stilo, they took a step backwards. they got the chassis dynamics wrong.

the tipo gave us the dedra, delta, tempra, coupe, bravo, brava, marea, 145, 146, 155, 156, 147, (even gtv & spider with only minor changes to rear suspension), and there are others i'm sure i'm forgetting. all of the tipo family have good chassis dynamics. thats widely acclaimed.

the stilo was a completely fresh start, and it didn't work out, which is why there are no other cars based on it, why the platform is now dead, and why the grande punto and new bravo had to be started from scratch (although secretly the new bravo is a tweaked stilo platform hence the speed of development, but shhh , that tweaked stilo will be used for the 147 replacement). stilo was such a mistake fiat cant even use the name on a new car for fear it would put people off.

even wiki says "Critics also attacked the car's excessive weight and its semi-rigid rear axle which was seen as a step backwards from the acclaimed set-up used in the Bravo/Brava and which resulted in handling many found uninspired and uninvolving."

i hate to sound like yet another stilo hater, but there are reasons for its failure.
i'd rather have a tipo every day of the week, especially if you're talking about a platform on which to base a 2.4 20v turbo. stilo isnt up to the job imo.

 

[sediciRich]

perhaps my mkV golf isnt so bad!!

rich

 

[sediciRich]

Thanks and it will be completed no matter what it costs me!! looked at your link for your vehicle and you seem to have completed it to a quality standard.

Where would one get such an ECU and who would do the remap, obviously not something I can do myself!

For 5 cylinders you have a number of options, real world ecu sometihng like the omex 710 will do. If you have a wish to go for something even better then the pectel sq6. You will notice a huge price jump thats it with ecu's. But dont talk about it here on a forum call the guy who mapped mine Phil Lanes at GandG motorsport 07717885420 .

rich