[PatchyBoy]

I bought a 2010 Linea T-Jet, from the first batch. I was and still am in love with the car. After pampering her with OZ Racing alloys, Alcantara & real leather upholstery, DIY Cruise Control install, DIY quad projector headlights and a switchable remap from WolfMoto, I was under the impression that there is nothing more to do. That is till I met @Keroo1099, @adneo and @wildy.

We are members of a WhatsApp group and the topic for discussion was fitting a bigger intercooler in the T-Jet. I reached out to my friends in Poland & Russia - the guys who helped me with the cruise control install - and bombarded them with questions. They were kind enough to answer all my questions. I was surprised that the IC in the European T-Jet seemed to be more efficient and assumed it was due to the colder climates there.

I missed asking one critical question - a picture of the IC. When that realization dawned on me and I did ask, I was sent this pic by a friend from Russia and it took me several minutes to pick my jaw off the floor

So, Fiat in all its wisdom had given a bigger IC to a colder climate and a matchbox sized IC for the tropics. Meanwhile, @Keroo1099 had got a bigger IC installed and was pleased with the results. So it was time to go shopping.

As the car was approaching 90K Kms, I decided to club the IC install with the service. Since I had recently moved to Kolkata, decided it was going to be a DIY. After searching a lot, I decided to get an IC from AliExpress (yeah, I know, cheap chinese stuff). The shipping was more expensive than the IC itself, but still worked out cheaper than some performance ICs offered by name brand establishments.

The new IC arrived surprisingly well packed (this box was inside another box) with zero damages -

I also ordered a few pieces of silicone couplers, 2" aluminum piping and some T-bolt hose clamps

Not to forget the reducers, as the new IC comes with 2.5" inlet & outlet, but Fiat's plumbing is 2"

Now that I had everything needed, it was time to roll up my sleeves and get to work. Once I opened up the bumper and removed the stock IC, I was shocked to find that it was a tube & fin type IC, weighing in at 1.5 kg.

The replacement I had bought was a bar & plate type, weighing in at 3.4 kg.

The OE and the new IC side-by-side

I had to design a robust bracket to hold up the IC. There are two holes in the crash bar and I decided to use them and came up with this design

Once mounted in the car, it will look like this.

After the dry fit, I took it apart again, painted the bracket and mounted it. I had to make some modifications to the bracket to push the IC back a bit.Then proceeded to complete the plumbing. The final outcome looked like this-

Once I had the bumper back on, I decided to do a run of the same route I did before changing the IC, almost under similar driving circumstances. Of course I also completed the regular service of Engine Oil change with all filters change.

The FE had improved by almost 17%

With Old IC

With New IC

Also plotted IAT graphs after logging the drives using an ELM327 dongle and TorquePro App

Stock IC Chart

New IC Chart

The total cost for the install was around $200, incl shipping. If the 17% FE gains remain, this is going to pay for itself very soon.

Observations after the install -

1. Low end grunt has improved tremendously. Most of the drive charted above are in narrow village roads. I was now able to drive in 3rd gear instead of the usual 2nd.
   
2. Driving character has improved and the car feels eager to pull
   
3. The moment I cross 40 kmph, the IAT starts dropping and continues dropping reasonably, as long as I don't go back to crawling
   
4. Even when I do have to crawl, the IAT remains stable and doesn't shoot up quickly like it used to do with the stock IC
   
5. FE has improved by 17%. Even if we take away some portion as due to the new oil & filters and a slightly lower ambient temperature, I am sure more than 10% is contributed by the bigger IC
   

I would only like for Fiat to explain themselves for doing this to unsuspecting Indian customers. What were they thinking? How does it make any sense to give a bigger IC to colder climates and a small IC to the tropics? This small tweak could have saved the fate of the T-Jet. An absolute engineering disaster leading to the demise of an advanced product for its times. The car got continuously hammered for the poor FE and other car makers happily laughed away with customers.

I still do not understand the design logic of Fiat. I was able to install Cruise Control for less than ₹ 5000 and a bigger IC for approximately ₹ 10000. Fiat could have at least offered the Cruise Control & a bigger IC in their then flagship product. Guess they weren't too keen on the product success. They never seem to be.

[SDP]

Thread moved out from the Assembly Line. Thanks for sharing!

[adneo]

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At the outset, I would like to thank Raaj aka wildy for getting like-minded people together - people who would not call you crazy even when you go overboard. Then of course, I am immensely grateful to both Kedar Sir and Rajan Sir for believing in our theories and putting in both, time and money into something which was based on just a hunch.

So, the Mahabharata behind this starts like this. I know wildy is still waiting for my TJet purchase Mahabharata, but that's still getting compiled.

So, I bought a TJet going totally against wisdom and sanity, just because I loved the way it drove and couldn't get any car below 20 lakhs offering similar pleasure.

During my initial days of ownership I hadn't worried too much about the FE, since i was mostly driving within city limits and 10 km/l was pretty good for me on stretches where my Alto K10 gave 12/13 km/l.

Now comes the twist: I was on a tour of Ooty and I was mentally ready to see abnormally low FE figures, but wait, I was actually seeing similar FE figures even on the slopes while driving most of the time in 2nd gear. Err... something not adding up man! On my return trip, another discovery was that after running for long periods the car seemed to lose power and became sluggish.

I discussed both these issues with Kedar Sir and he was initially skeptical, since he never thought the TJet, a car known for bad mileage would give similar to better mileage in the hills both, while going up and down. Fortunately, his friend was on a trip to Ooty on that day and was on the Wolf Map 2 going uphill. He called him and bang came the reply - 11.4 km/l!

Well, we knew either something wasn't right, or we were missing something in the equation. We started breaking down the components affecting both power and mileage and it was also reported by a few owners in the past.

So, how is this car different from a NA? it uses forced induction and an intercooler to cool down the charge air. As we already know, Fiat had made a mega mistake by taking out the intake snorkel from above the radiator into a position behind he headlights so that it keeps sucking in the hot air from the engine bay, we thought of targeting that.

One day I took my trusted high RPM table fan to Kedar Sir's place and blew air both in the air or the intake and the IC. We noticed that though at the intake position the fan did make a minor difference, the air flow near the IC had zero impact.

We split up the approach, Kedar Sir would try a jugaad cold air intake while I targeted the IC. We also got an ELM OBD scanner to log data.

While Kedar Sir started accumulating parts to put up a CAI, I went through the internet to discover that indeed high IAT could result in drop of FE and loss of power. By that time Kedar Sir had put up a custom CAI and we did a couple of runs while logging them, the data showed that the CAI was helping the engine breathe better, but the heat was taking away the leverage. Next, we thought of doing something really crazy.

Initially, I wanted to spray the IC with spirit during a run, but was worried it might catch fire as it easily reached temperatures of 60+. So, the next best effervescent thing which was cold as well, was soda. Yes, you read it right, I sprayed Kinley soda water out of the fridge onto the IC and did couple of runs alone. It seemed a little silly to myself as well, but man did the car change its character when the spray went on the IC! I was shocked to see the data. I have a video of a run and will upload in sometime. When I called Kedar Sir, initially, he was also shocked. I still remember him saying, "You sprayed soda on your IC?!" We both went for a run and as expected came back amazed. Now, we knew that we were onto something.

But how do we benchmark it against a production car? Enter the Baleno RS with a pure manual transmission. I got a TD setup and coaxed then SA to let me plug-in the scanner. Good chap; he was very excited and had never seen a crack customer like me! Initially, I saw the IAT was high just like the TJet while we stood at a signal, and I was thinking now everyone will say I sent them on a wild goose chase. But once we started rolling, I was so shocked that the TD continued for 5 kilometres in peak city traffic. The Maruti IC brought down the IAT drastically on the move and just at 40 km/h, it went down from 60 to 28! OMG Fiat, what have you done! No wonder the Baleno has such a good FE. We did another test with a Ford Aspire and got the same result - IAT kept going down where the TJet got heat soaked, stayed at 60 and even went past 65.

We knew the Compass TJet ran a higher state of tune, but the engine core was the same. So, we took some data of the Compass TJet, an what a surprise, the air intake has been revised along with a bigger IC. We had also noticed that both the Baleno and the Ford ran a bigger IC and the one on the Jet looked like a wafer in comparison.

Based on a lot of data collection and lots of brainstorming based on contributions from all our friends, we had concluded with conviction that the IC was the weak link and no matter how many power tweaks or remaps you do, if you don't fix the air quality you can't get much out of it.

Following this, Kedar Sir took a really bold step of going for an upgraded IC and we can't thank him enough for this. After all, we were not mechanical engineers and at best, quacks trying to think smart based on some research. The effects were immediately noticeable - the mileage and linearity of power delivery went up by notches.

Following this, Rajan Sir thought of reaching out to his friends who had helped him with the CC mod from EU and the picture of that Linea with a huge OEM IC fell on us like a nuke!

The results speak for themselves and knowing Fiat's attitude, I doubt if anything will transpire out of this. We wanted Rajan Sir to script down his experience so that people could benefit from our collective research and understand a saying which my professor taught me during my engineering days, "there is nothing called a bad product, there are only bad engineers or engineering"

I hope our efforts will help instil trust and faith in the TJet for all those planning to sell the car due to poor FE. Trust me, if you get it right, there is still no other car like this in the market at this price point.

My wife wasn't happy when I took the risk of buying a Fiat, but when I tell her that this might have been the biggest gamble of my life, she tells me astutely like an HR, "anything in life which gives you pleasure is injurious to health! Have you ever heard healthy food being tasty? "

[extreme_torque]

10% gain in efficiency just by replacing the intercooler with a bigger one seems a little far fetched to me but I cannot argue with either the numbers or the stupidity of Fiat. Its not the first time. Back in the day I had a Fiat Palio 1.2 another car which was canned for fuel efficiency. Now I am not saying it was as fuel efficient as the wafer light Wagon-R but given its weight and engine, it was fairly okay. Fiat being Fiat did not calibrate the Odo meter properly so when gps'd the odo under read (yes you read it right!) by approx 5% compared to around 7 to 10% over reading on the competing cars. So essentially the car was atleast 5% more economical and about 12-15% more economical factoring in the 10% odo error that is generally considered acceptable. Good old Fiat and what a way to let down great products!

[Dr.Naren]

Good DIY and happy to read about the gains. I have S-Cross 1.6. IAT is always above 50 degrees in most of the driving conditions. I have also observed that engine is very sensitive to IAT. I have even timed my car (0-100) at IAT 35 degrees and 55 degrees. There was good 0.6 seconds difference. IAT in my car is always 20 degrees more than ambient temperature. It has touched even 65 degrees in Bangalore traffic .

[keroo1099]

Super post Rajan. Hope it gives others who understand the harm a high IAT does for performance and economy the confidence to make a relatively easy switch.

I haven't driven my Jet enough after the IC change but can concur with your comment on better bottom end grunt and eagerness to rev.

Cheers

[sandeepmohan]

Originally Posted by PatchyBoy

I was shocked to find that it was a tube & fin type IC, weighing in at 1.5 kg. The replacement I had bought was a bar & plate type, weighing in at 3.4 kg.

What is the difference? From pictures, I can't tell apart from the core size being bigger.

I had a 2011 edition and did miss cruise control from time to time but hey, you did not buy a Linea T Jet to flip a switch and stay at a fixed speed on the highway. You floored it.

Originally Posted by Dr.Naren

I have S-Cross 1.6. IAT is always above 50 degrees in most of the driving conditions.

It is a Fiat Motor under the hood. For all you know, it must be using the IC Fiat have specified, which is flawed.

To me, all this sounds like some cost cutting measure. They must have decided to use the same IC found in the 1.3l Multijet, for the T Jet. To Fiat, its like, why bother manufacturing another IC for a car that isn't going to sell all that much anyway.

For those who own a Abarth, there is a possibility for the car to perform even better.

I still feel the IAT needs to come down more but I guess a lot has to do with the fact that the air being sucked by the intake is already hot to some degree and there is only so much a better IC can do.

While I no longer own a T Jet, I have been in conversation with keroo a lot on the subject. I never did think it was the IC. Having said that, I still believe the air intake is located at the worst place possible.

[PatchyBoy]

Originally Posted by sandeepmohan

What is the difference? From pictures, I can't tell apart from the core size being bigger.

That is the difference. A bigger core cools better.

I still feel the IAT needs to come down more but I guess a lot has to do with the fact that the air being sucked by the intake is already hot to some degree and there is only so much a better IC can do.

Agreed. Rerouting the air intake to suck colder air from the front grille is in the works.

[sandeepmohan]

Originally Posted by PatchyBoy

That is the difference. A bigger core cools better.

Yes but what is bar and plate vs tube and fin? Are they not both tube and fin type IC?

[scorpian]

Have you had a look at the inter-cooler from Sx4 ddis?
Its bigger then the one in your stock fiat, infact the one you have purchased from aliexpress looks very identical to the one that's mounted on the sx4 ddis. Comparatively maruti has installed a bigger inter-cooler on the same unlike the one made by fiat.

For anybody else who wants to try this could walk in to MGP and buy the stock sx4 ddis inter-cooler and mount it.Would save a lot of downtime from ordering on aliexpress.The hoses etc could also be picked from sx4 parts bin.

Part number for intercooler is 13620M69K50 costing 3694.00
Part number for hose is 13663-55KDO and 13664-55KDO

Regards,
Manoj

[anand.shankar]

@Scorpion
I assume the same would fit the MJD as well, wouldn't it ? I have a 75 mjd Punto, thinking of this would make any difference. Time to take out the ELM adaptor and install the Torque app.

[blackwasp]

Originally Posted by PatchyBoy

We are members of a WhatsApp group and the topic for discussion was fitting a bigger intercooler in the T-Jet.

Thanks for sharing, your results are key to convince me to get a new intercooler on my Abarth. At the 45k service, I will have a word with my SA and get his opinion as well on the same.

Originally Posted by scorpian

Part number for intercooler is 13620M69K50 costing 3694.00
Part number for hose is 13663-55KDO and 13664-55KDO

Thanks Manoj for sharing. This route seems more logical considering it will be easily available at local Maruti workshops. I will give it a go soon...

[scorpian]

Parts link for the intercooler.

http://oriparts.com/7/53/1586/485755

@ Anand.Shankar
If its at the same location as the linea, then it should definitely be possible to mount. It would for sure make a difference.I would say if you can fir this with minor mods, go for it.

@blackwasp
Buying from MGP will save time/cost,even quality of product would be at par.Replacement in future would also be straight forward. Would just be as simple as buying the sx4 IC,and the two hoses,then remove the bumper,mount this and refit the bumper. Could be done in less then a hour if all parts/tools are at hand.

Regards,
Manoj

[PatchyBoy]

For starters, the inlet & outlet for the T-Jet IC are parallel to the core, but are perpendicular in the SX4. Secondly, we will have to check if there is enough clearance to mount the IC ahead enough to be able to plumb. Finally we also need to evaluate the effect of adding an additional 90° bend.

[raghu.bramha]

@PatchyBoy, Wow Bro, just the coolest DIY with so much value for money. Hats off to your perseverance. Keep us posted on the performance in the coming days. Will surely get it done for my 1.3 MJD as well with your inputs.