Twin Turbo

[Everhard Dawnwood]

Wanted to try it and went with a Walea UTE with the SL4 engine, installed the twin turbo manifold and the Walea turbos.

However, it doesnt reaally work, I tried the smallest turbos I could get and even with those, the engine had to pass 3000 rpm to build boost and it didnt provide much power, I couldnt make the car accelerate beyond 120 km/h, despite it said it developed over 300 bhp.

I then tried fiddling with bigger carb and other tubos, it didnt really change anything except the bigger the carb and turbos, the more bhp it showed having, but it drove exactly the same regardless. :-/

[Creative Pudding]

Did you tried to add extra air intakes? Twin turbo will use more air than the engine bay can provide, which will reduce the turbo output. It could be an issue. We will also investigate if this is a bug or bad setup.

[Everhard Dawnwood]

Yeah i used the small hood and small roof intake that I got with the DLC, I assumed it would be enough for the SL4? :-/

But ill give it a go with more/bigger intakes, I didnt really consider it, my bad though. :-)

[Everhard Dawnwood]

Did a little more tries, went with the LX4 engine instead and it works exactly the same as the SL4 with twin turbos.

Tried it with two 282cfm turbos, then the car had a hard time getting off tthe line and boost pressure didnt go up until it hit 3000 rpm.

I had the 1000cfm hood scoop and 1000cfm roof scoop along with the Walea intercooler installed on the car.

So I tried removing the scoops and the intercooler, the car acted exactly the same on the salt lake.

I then tried removing one of the turbos, written specs were updated with lower values and the boost pressure became lower, the car acted almost the same as with two turbos, top speed gone down from 183 to 178 though.

So I removed the twin turbo manifold and installed the stock L4 manifold, again written specs got lower, but the car would actually drive much better, with much more low end torque so it could actually pull itself off the line properly and the acceleration was just like when it had twin turbos, even the top speed was the same 183.

It seriously seems there are something weird happening with the twin turbo setup on the L4 engines or am I missing something?

[Creative Pudding]

Thanks for such an extensive report! We will investigate it and come back on this! You might just found a bug!

[Everhard Dawnwood]

No problem, anything to help :-)

[Doc]

I use a 400cfm turbo on the new SLE4 and its still a little boggy, a pair of 250s is a lot of air for the weaker 4 bangers. A pair of walea 250s is meant for the Walea V-6, which is double the power of the SL4/LX4.

[Everhard Dawnwood]

Thats what I been thinking too Doc, but I also tried with the smallest turbo as well and it didnt change anything.

In addition, the data sheet on the car shows some power and torque output, however the top speed remains the same 145 regardless of whether the car will actually do more or less than that.

Also, even if the turbo is too big, so the exhaust pressure wont drive it properly, the engine shouldnt lose all of its native torque, it should at least remain more or less the same as without the turbo.

[Creative Pudding]

Top speed on the data sheet does not change! It is the original state of the car, as you bought it. This will be later updated, when you actually go over that limit (but this is not yet in the game). We were thinking of updating it in the future, after you run a top-speed run on the bullet run. Think about it as the specs of the original car, not as a dynamic data yet. We also want to change the hp to use dynamo to actually test it instead of real time data...

I assume the problem with twin turbos is that they are connected "parallel" and not in linear, meaning they both need the air to fill the chambers and spin them up to working rpm. If we would change them to being in linear connection than the first would feed the 2nd and the charging would be much more effective and quicker. (Testing)

[Everhard Dawnwood]

Ok then, its just because the power and torque changed on the sheet there, but the idea of it being a static sheet is nice and maybe it would be neat to keep a static sheet and then have a dynamic one as well that will be updated when you do dyno runs etc, so that you can always compare the two against each other. :-)

[Creative Pudding]

yes, that is where we are going... just sometimes we get there a bit slow :P

[Everhard Dawnwood]

Haha no worries, you cant do everything at once, thats why we use versioning :-D

[Doc]

The power loss when the turbo isnt spooled does seem to high, like its a big supercharger dragging the engine down instead of a mild restriction in the exhaust.