[Nimish anthony]

At the outset let me congratulate you for the time and effort you dedicate to the T jet. DIY is the icing of the cake and glad to see that you have received substantial gains by changing the inter cooler. Would suggest to plonk an M32 GB to get the max out of the ride.

[i74js]

Just wanted to ask about the additional drop in pressure with the use of large IC? If the drop is in excess of 1 PSI against the original IC that has been replaced, will it not deteriorate the performance of the car?

There is a trade off between size of IC (reducing the temperature) and the pressure drop. Picking up up just about anything bigger without appropriate research may not result in intended gains.

Even change in plumbing, increasing / decreasing size of intake pipe, additional bend etc will have impact on the final performance.

Not sure if this is truly a DIY activity the way members are discussing about replacement with SX4 IC as a plug & play option for their cars.

[scorpian]

Any upgrade has a risk factor whether it will work better or worse. However this is personally my take on it, if i am willing to spend a certain amount and risk it to see if its going to help me gain something then i am fine with going ahead with it. There is already a positive change seen as posted by the person who has started this thread.Also a bigger IC is seen in other parts of the world for the same car.
There must be a reason why maruti decided to give a bigger IC for the sx4. I mean how much does one lose, cost of the inter-cooler plus some hoses,for 4k if you can get a better efficiency and better drive then why not try it?You never know it may be better like the thread opener has experienced.

Again this is totally my personal opinion.

[PatchyBoy]

Originally Posted by i74js

Just wanted to ask about the additional drop in pressure with the use of large IC? If the drop is in excess of 1 PSI against the original IC that has been replaced, will it not deteriorate the performance of the car?

There is a trade off between size of IC (reducing the temperature) and the pressure drop. Picking up up just about anything bigger without appropriate research may not result in intended gains.

Even change in plumbing, increasing / decreasing size of intake pipe, additional bend etc will have impact on the final performance.

Not sure if this is truly a DIY activity the way members are discussing about replacement with SX4 IC as a plug & play option for their cars.

Glad you brought that up. Let me elaborate -

Modern engines are different from what they used to be. The turbocharged cars of the present times need an intercooler because of the much higher power and efficiency demands.

The major difference of present day engines from the older models is that today the factory computer with numerous sensory inputs is watching what is happening and if the ECU senses a change, it alters the tune to correct it. It also means that for the intercooler its unlikely to get a gain in power, even if you do get a significant gain in efficiency.

Nevertheless, the fitting of a bigger intercooler is still quite valid for two reasons. One – The actual power gain from an efficient intercooler design over OEM could be between 5% and 10% with a temperature drop of 35 to 40 degree C. As this largely depends on the ambient temperature, we can conclude that the smaller the difference between intake temperature and ambient temperature, the better the cooling effect. Although it will not really change the stresses and strains on the engines, the cylinder temperatures are lowered a bit. However, this might not be enough to impact engine longevity and the like.

But, our focus is on the second – a reduction in pressure drop. There is always a pressure drop across an intercooler. Since the ECU has its boost pressure sensor after the intercooler, it means that it accounts for the pressure drop, whatever it may be. By running a more efficient intercooler, we won’t gain any more boost because the factory ECU will be pulling the turbo back. Yet, therein lies the main benefit.

Even though there are additional advantages like slightly better combustion, they are barely noticeable. The main advantage is that it will have a significant impact on the turbos’ longevity because the turbo will be spinning at lower RPM. As a result, the machine will last longer.

All turbo cars can benefit from intercoolers and modifications/improvements can be made on the factory fit intercoolers. You would want as much air to be sucked into the engine as possible. If the intercooler hinders the airflow, there is a risk of you actually losing power. Normally, the larger the intercooler, the longer it resists heat soak, but can create throttle lag and can be too large to physically fit. Therefore, for maximum benefit, you need to get the optimum sized intercooler. I guess I have done just that. I could have gone for a 230 mm intercooler - the largest that would fit, albeit with some cutting of the bumper. I did not, because I did do my homework first.

The benefits are very visible to me. Here are the FE numbers from today's run. 14 kms on good roads, 3 kms village roads, with reasonable surface. Rest really bad broken roads. This is all city run, with ACC at 22 degrees. The ambient was lower due to a shower and hailstorm in the evening.




Here is a graph plotted based on this data. The stock IC would run hotter in winter, when the ambient was around 15 degrees. I also added intake manifold pressure for you.



Hope this addresses your observation.

[deathwalkr]

Nice DIY. Hope you keep updating this thread and new findings if any along the way

Has there been any performance drop?

[dhanushs]

Originally Posted by PatchyBoy

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

Stock IC Chart

Attachment 1740409

New IC Chart

Attachment 1740408

Hi,

Are you sure the IAT stays same across the rpm/load or rather boost?
Wondering for a turbo vehicle, at what point is the IAT constant?
Also, do you know if the IAT's in this graph is measured before the turbo or after the turbo till intercooler, or from intercooler till manifold?
What is the delta drop in temp across both ends of the InterCooler?

Ideally, a bigger intercooler will mean a slower response time to build boost. Hence a slightly delayed throttle response and hence a sluggish kind of 'seat-of-the pants' feel. However, will give bigger numbers on a dyno.

[keroo1099]

Originally Posted by dhanushs

Ideally, a bigger intercooler will mean a slower response time to build boost. Hence a slightly delayed throttle response and hence a sluggish kind of 'seat-of-the pants' feel. However, will give bigger numbers on a dyno.

If you are in Bangalore you are welcome to come and try my Jet with a bigger IC (same size as Rajan's) and tell me if it feels sluggish compared to a regular Jet even on the stock map (I have a wolf remap). Forget the Jet, you can drive and decide if it feels sluggish compared to any car with a forced induction.

[dhanushs]

Originally Posted by keroo1099

Forget the Jet, you can drive and decide if it feels sluggish compared to any car with a forced induction.

wow. So much power after fitting an intercooler ? Good for you.

I’m still trying to figure when the power is developed and delivered to the wheels.

[keroo1099]

Originally Posted by dhanushs

wow. So much power after fitting an intercooler ? Good for you.

I’m still trying to figure when the power is developed and delivered to the wheels.

It's not the power it's the power delivery which has become a lot more linear post IC mod and a DIY cold air intake. It has almost eliminated the turbo lag which makes the car more drivable in the city aided by a sharper throttle response. I have no idea if it develops more top end power with the new IC and I don't really care. All I know is that the engine sounds a lot happier when I drive it with this combination of IC and CAI.

All the good bits move up a couple of notches if I switch to the remap mode.

[venkyhere]

lovely thread.
Has the new IC improved power output (discount any remaps) ?
- actually thats not easy to answer. Due to the following reason :

When fiat advertised XX bhp and YY Nm peak numbers, how was it measured ?

while on a dyno where the IC will definitely get heat soaked (experiments' data proves it), but no air drag
OR
while on actual high speed running (less chance of heat soaked IC, but definitely pulled back by air drag)

unless we have a clear answer to above, nothing can be said about power gain in real world.

what we definitely know, is that the quality of air entering is closer to how the whole system is meant to work. This will mean, for the same throttle input as before, the combustion happening is more efficient. This will in turn mean :
1. better FE.
2. better low end grunt as more bang for buck since at low speeds, when the charge air is low on boost, still the benefits of lower IAT than stock, will make a difference

[PatchyBoy]

Originally Posted by dhanushs

Are you sure the IAT stays same across the rpm/load or rather boost?

In a normal city run, it shouldn't vary much. I do need to do a highway run and check the behavior over various load conditions.

Wondering for a turbo vehicle, at what point is the IAT constant?

I doubt if it will ever be constant. IAT would creep up when stopped and will get lower as the car picks up speed.

Also, do you know if the IAT's in this graph is measured before the turbo or after the turbo till intercooler, or from intercooler till manifold?

Quoting from the T-Jet engine training manual -
The intake manifold also carries

• The motorised throttle,
• The intake air pressure/temperature sensor,
• The injector rail and injectors

What is the delta drop in temp across both ends of the InterCooler?

I did measure with a hand held IR thermometer and here are the readings



Please do note that these are surface temperatures of the plumbing. Unless we have internal temp probes on the hot & cold side of the IC, we cannot get accurate readings. You can see that the IAT reading was a maximum of 53 degrees from the chart below.

Here are the stats from today's commute



And here is a chart plotted with today's log

[TheTeacher]

Awesome work, guys! What a fantastic detective spirit and what a great piece of engineering! Fiat should be ashamed!

Originally Posted by adneo

I went through the internet to discover that indeed high IAT could result in drop of FE and loss of power.

You answered a mystery for me. My T-Jet is now 5 years old. In the first couple of years, in peak summer in Bangalore, with the a/c on at 20C and sitting in bad stop and go traffic, my Jet has stalled 3-4 times with complete loss of power and a weird, loud noise. There was shuddering as well. Vecto Motors couldn't reproduce it (naturally) and didn't have a clue as to what the issue was. For whatever reason, the problem didn't recur. I don't use the car much (run < 28.5 k) and try not to go out in bad traffic. But it looks like too high temps for the air intake.

Once I'm in the car, the a/c is always on, and I've always had terrible mileage in city as well as highways. Maybe my driving style. Or maybe my air intake is in a worse position than normal.

Now I'd love to get the CAI and IC mods done. Problem is, I'm not a DIY guy. Anybody you know who can do it for me? I'd be happy to pay for quality work. Thanks.

[Wildy]

Awesome work Rajan Sir. Hearty congratulations. I'm glad to have you, Aditya (Adneo) and Kedar Sir (keroo1099) and few more great veterans in our whatsapp group

@folks, is there any professional garage/good mechanic who can do such work in Bangalore if we get all the necessary items for the installation?

If any leads, please share.

[adneo]

Originally Posted by TheTeacher

Awesome work, guys! What a fantastic detective spirit and what a great piece of engineering! Fiat should be ashamed!
You answered a mystery for me. My T-Jet is now 5 years old. In the first couple of years, in peak summer in Bangalore, with the a/c on at 20C and sitting in bad stop and go traffic, my Jet has stalled 3-4 times with complete loss of power and a weird, loud noise. There was shuddering as well.
Now I'd love to get the CAI and IC mods done. Problem is, I'm not a DIY guy. Anybody you know who can do it for me? I'd be happy to pay for quality work. Thanks.

Glad that our efforts helped in dispelling the doubts in the car. The simple equation is combustion is a combination of Petrol and Oxygen and this ratio is very crucial in ensuring optimum results in various scenarios. But another variable in the equation is the temperature which reduces the oxygen density hence forcing the ECU to compensate by pumping in more fuel to produce similar result. There are other issues as well like premature ignition and all. But this is the most basic explanation.

Given the TJet's nature, the car pulls in any gear till 3rd in stop and go traffic, but for best results please try not to lug the engine in higher gears and make generous use of the gears.

There are quite a few who are planning for this mod, and if you could PM me your contact, we could discuss further.

[TheTeacher]

Originally Posted by adneo

Given the TJet's nature, the car pulls in any gear till 3rd in stop and go traffic, but for best results please try not to lug the engine in higher gears and make generous use of the gears.

There are quite a few who are planning for this mod, and if you could PM me your contact, we could discuss further.

Thanks, adneo, sending PM now.

I really, really hate lugging, and have never done it purposely / consciously in my 42 years of driving. I occasionally miss shifting down, but that's because I drove an automatic for 2+ decades in the US, and when the brain is on auto pilot, it thinks the car will shift on its own :( If anything I am guilty of going to higher RPMs in each gear than the average driver before shifting up.