Alfa Romeo 4C Forums banner

1 - 13 of 13 Posts

·
Vendor
Joined
·
1,112 Posts
Discussion Starter #1 (Edited)
Hello 4C fellas,

As most of you know, among other projects we were also working on GMS Stage I ECU tune for Alfa Romeo 4C. We are a bit late to the game with all the different tunes flooding the market, but I wanted a map to fully utilize my current supporting power mods (GMS 3" exhaust, GMS prototype CAI, Scara73 intercooler), so we decided to go with our own tune.

GMS Stage I engine tune, was developed in cooperation with Slovenian tuner - Enigma motorsport and provides potent and reliable power and torque figures from 1.75 TBi 4C engine.

Arguably the ultimate engine tune on the market, for stock or lightly tuned Alfa Romeo - 4C engine. Why? Because we believe there is more to an engine tune than just dyno horsepower chart.

Our tune reduces mid range turbo surge. All the engine tunes we have tested and compared, were providing maximum turbo boost ASAP but the restrictive exhaust and limited engine head flow caused so much backpressure that turbo surge was noticeable in the low-mid range. Boosting more air into the engine than it can take and choking the turbo is useless and it's affecting turbo life.

We have reduced lower rpm boost to flatten torque and decrease torque spikes for extended transmission life. We have revised camshaft overlapping for reduced EGR effect, lower combustion temperatures and more peak power at higher rpm range. We have optimized boost for higher peak power, with expected power of up to 280hp on 100% stock engine and up to 334hp with supporting mods (GMS 3" exhaust system, Scara73 intercooler or Eurcompulsion intercooler - haven't tested). We have revised and set higher RPM limit at 7250 for wider powerband coming strong out of the corners. We have provided optional high flow cat / decat option (no check engine light) and fuel overrun option for GMS signature throttle lift off exhaust sound effects. Ignition timing is optimized to run with 98 RON or 93 AKI or higher fuel grade. For user with only lower grade fuels available, custom map can be provided upon request.

So what are the power figures? Well this is something we can argue about in endless discussions. Measurements will vary from dyno to dyno, ambient conditions, drivetrain powerloss etc. Low power figures won't sell the products and high power figures will leave you disappointed when you will go for independent dyno measurement or loose against same hp car, so I'll try to be as objective as possible.

We were using a braked dyno, able to simulate road resistance and used efficient fan blowers directed into the intercooler. Ambient temperature was between 10°C - 15°C. We could say that conditions were perfect, not something you get on a hot track day.

Stock 4C (stock ECU) - 345 Nm, 246 hp
Stock 4C (GMS Stage I ECU) - 421 Nm, 300 hp
Modded 4C (GMS Stage I ECU + GMS 3" Modular exhaust w/ decat + Scara73 Intercooler + GMS prototype CAI) - 423 Nm, 334 hp

This were the max values we got on first pulls when intake air temperature (IAT) was low and no heat soak has yet affected the car. I would call this dyno queen car runs. After a few pulls the power is down and keeps falling down, hand in hand with increasing IAT, which in one test case, where we ran without external fan, got as high as 70°C. At this IAT temps, no engine map will yield anywhere near 300hp as the ECU starts retarding the timing as much as it can to prevent engine knocking. This I would call the worst case scenario run. Let's say a hot track day with extreme ambient temps and a cover over side flank intake ducts. Probably not gonna happen but to get the idea between ideal and not so ideal conditions. We are talking about 40-50hp difference here only due to different conditions, not to mention the importance of fuel quality. So what's the point?

Well the point is to offer an engine map that will extract the most out of our 4C engines and do that safely, without major mods. You can run it on a completely stock 4C, getting 300hp on a short dyno pull is doable, but the car just won't stay at 300hp due to too many restrictions (stock exhaust, stock intercooler) causing high IAT. Still on a trackday or backroads blast, running stable at about 270-280hp is a decent gain over stock tune and with optional burble it will get grin on your face everytime you release the throttle, for sure. If you are more track focused user and want to extract the most out of your 4C without too much of involvement then GMS Stage I tune with supporting mods of GMS 3" exhaust (decat in my case) and uprated aftermarket intercooler (Scara73 in my case) will push out up to 340hp in perfect conditions. On a track on a hot day you are probably looking into 290-300hp figures or perhaps a bit more with proper control of IAT. With GMS free flowing and wrapped 3" exhaust, GMS carbon side scoops and GMS carbon rear cooling hatch you can lower the engine bay temps, increase intercooler flow, decrease backpressure and while this sounds pretty much as a marketing, in the end it all adds up whether you like it or not. I do what I believe and my engineering understanding tells me it is right. I tune my car for myself in first place. Selling and making a revenue from sold parts is a bonus, allowing me / us / GMS further development. Some like us some not, I take that as a gift. A gift to compete, to get better, to work harder. It's a gift I thank motorsport gods for. We are the only on the market offering some unique solutions not available elsewhere and more are to come. I wanted the same with ECU tuning. I was running Alfaworks Stage I ECU and I was very happy with it, I'd recommend it to everyone, but as probably Jamie doesn't run GMS parts, neither I wouldn't Jamie's if at the time I had a chance to have our own tune, but I didn't back then. Well, the time has come, so I pushed the button. I couldn't do it myself so I got the best team I could in Slovenia and I'm honored they were willing to cooperate. Thank you Enigma Motorsport.

Now back to the red string. Whichever tune you run, you will end in the mentioned ballpark of the hp let it be GMS, Eurocompulsion, Scara73, Alfaworks or perhaps some other. It depends on your mechanical hardware, fuel grade and ambient conditions. Spending money on GMS Stage I ECU tune on a stock car that already has other ECU tune is probably useless unless you do it for overrun feature or because you like our products. For true gains, get the exhaust flowing, get intercooler working and get your engine bay well vented. It will do magic to hp figures.

Some say 0-100km/h is valid, others say dyno is, third say 100-200km/h is valid. Everything is valid if you ask me, but everything can be manipulated as well. For me lap times matter. GMS 4C will run same tracks, same driver, we'll see. We already proved in a past that we are competitive and I believe this upgrade won't slow us down either.

Thank you for your time guys and stay cool.

Regards,

Rudi

Here is the dyno run compilation and the strongest pull graph:

gale_4c_max_final.JPG

 

·
Vendor
Joined
·
1,112 Posts
Discussion Starter #2 (Edited)
And the long awaited dyno graphs.

100% stock 4C with stock ECU. This dyno was always a bit optimistic on torque figures, but that's not the key thing here.
STOCK ECU - TUNKKA.jpg

100% stock 4C with Alfaworks race ECU and provided base map.
ALFAWORKS RACE ECU - STOCK HARDWARE.jpg

100% stock 4C with Alfaworks race ECU and provided base map. 3 consecutive runs without any additional cooling to the intercooler. Here the IAT got to about 70 degrees and you can clearly see how the retarding of ignition timing to prevent knocking, caused significant power loss. The power went from 290hp to 256hp on same car in just 3 consecutive runs. It happens the same with tuned OEM ECU's just a bit less aggressive. Freeflowing exhaust, uprated intercooler and sufficient cooling would change the thing completely.
GMS - ALFAWORKS CONSECUTIVE RUNS.jpg

100% stock 4C with GMS Stage I ECU. It's par on with other tuners but we were measuring in quite cold conditions so it is a bit high on power compared to others. Also all the following dyno runs were run on other dyno, so the HP and NM figures are not directly comparable with the upper dyno graphs.
GMS STAGE I ECU -  STOCK HARDWARE.jpg

Modded 4C with GMS 3" Exhaust w/decat + Scara73 IC. Noticeably higher top end power with basically no increase in torque compared to previous graph. The reason for that is that with these two mods the backpressure is significantly reduced, allowing the hard working turbo (it's running out of its optimal efficiency range on tuned ECU's) to still provide enough of boost, to maintain the power all up to the rpm limiter. Reduced backpressure means more boost in the intake which means more high rpm power. Or explained in other words, it's how much of air can your engine flow through the head, not how much boost you run. Shitty engines need a lot of boost to generate horsepower. We had an old Renault 3.0 V6 engine that ran about 200ps stock and with 1.5 bar of turbo only gave about 300ps, because there was a lot of backpressure and poor flow, while BMW S50B32 engine which ran 300ps stock, ran over 400hp on 0.7 bar of boost. That's efficiency. I believe there is at least additional 20hp of HP hidden in the porting of the engine head of 4C.
GMS STAGE I ECU -  MODDED CAR.jpg

Conclusion. It's all written in the previous post, the graphs here are just to back up the theory. Long story short. Free flowing exhaust and efficient intercooler are by far two most important things to look for if you want power. Pushing stock engine on restrictive exhaust, cat and undersized IC won't make you faster on the track. At least not for long. Before going for a bigger turbo, I'd rather have my engine head ported than stuffing even more air in it than it can take. More boost = higher temp and higher temp = less hp. But as friend of mine once said. You are not making car faster without sacrificing something else. You are just moving the balance slider from comfort <> race and wise versa. And I tend to agree. Exhaust gets louder with free flow, semislick tires get louder and extra grip kills the brakes, so you install BBK and race pads and then you get a squealing brakes, and then the rubber bushings start to give up and you install the uniballs, then you drop the AC to gain the edge on weight and power and then you take off everything you don't need from a car and add aero and by the time you start seriously outpacing other 4C's your car is pretty much "barely" street legal. But, it's how I always ran all my cars and the only way I know it and I love it. Who cares about audio system and comfort. the 4C is not about that, it never will be. It's just so raw, intimidating. I like it just the way it is coming all together. A seriously fast, analogue-digital, mid-engined bolide that I'm afraid of everytime I sit in it.
 

·
Registered
Joined
·
307 Posts
I have one question, you have used AW Race ECU as well. Are you able to replicate/get close to the throttle control of AW Race? Maybe the only positive surprise for my part... To me, throttle control was superior to OEM ECU. OEM throttle is very sensitive in the lower region, making it harder than needed when you are on the limit. Throttle is simply does not feel linear, quite sure its a trick AR used to make the car feel faster in a straight line.
 

·
Registered
Joined
·
307 Posts
I tried the Pogea tune on a fellow owners 4C, it seems like that had the same "curve", but have not tested Pogea on track.

Did you notice the same on AW Race, a improved throttle control? And is it something you would consider looking into for your project?
 

·
Vendor
Joined
·
1,112 Posts
Discussion Starter #7
I drove stock ECU, AW race ECU, AW Stage I ecu, GMS stage I ecu, EC Stage II ecu. Scara73 ecu and unknown tune on a customer's car and didn't notice much of a throttle response difference between these to be honest, but as mentioned, I wasn't focusing on it so I cannot really say. I always drive DNA in "R" and I did change it to "N" and "AW" a few times just to see what it does and it kills the throttle response greatly, so I'd say it has to do more with the throttle pedal sensor and DNA selector than the engine map itself.
 

·
Registered
Joined
·
307 Posts
AW race had more the feeling of "All weather", you had more pedal travel.

I think OEM tune feels "lumpy" at throttle adjustments, but when thinking about it, AW race had less torque(yes, surprise!) up to 2500+RPM, so maybe your intentional reduction of mid range boost unintentionally improve this.
 

·
Registered
2016 Spider
Joined
·
142 Posts
Is there a way to make the tune gets activated in Dynamic and Race mode? Would be nice to keep it the way it is in Natural mode so we do not stress out the power plant when we do not want to.
 

·
Vendor
Joined
·
1,112 Posts
Discussion Starter #10
DNA pretty much only affects throttle response and ESP, so it would be very hard to make it affect the engine maps. How much you stress the powerplant depends solely on how you drive it. You can have Stage I tune and cruise around without any additional stress to the car compared to OEM engine maps. When you push it, the tear and wear is increased as it is with every power increase.
 

·
Registered
Joined
·
973 Posts
DNA pretty much only affects throttle response and ESP, so it would be very hard to make it affect the engine maps.
Squadra Tuning does that. They lower the power in A, by the way, to make it more safe in the rain.
 

·
Vendor
Joined
·
1,112 Posts
Discussion Starter #12 (Edited)
I would say the engine map remains the same, but depending of the DNA selector, the accelerator pedal at 100% only partly opens the throttle body and is limited at A an N, so it doesn't ever get to 100% open and therefore the boost is limitrd and so are the power and torque are lowered. At D and R with accelerator pedal at 100%, the throttle body opening is 100% and full boost is available. If they sorted it out with different engine maps, they have some serious mindpower in their team to do that as this would require a serious engineering. I doubt it, but nothing is impossible.
 

·
Registered
2016 Spider
Joined
·
142 Posts
I thought about the capabilities of ECU as well which of course is question for me, selecting different maps using DNA switch means the ECU should have more banks to hold different mappings and with the position of DNA the appropriate mapping to be called on the fly. Not even sure if it is even possible as I do not have the tech specs of the Bosch ECU nor I am an ECU programmer.
 
1 - 13 of 13 Posts
Top