Turbos and timing

[JIMP]

Hello Humble

on a T1 turbo but carburated we made some tests and at 1.1bar boost it made it the best with 20o, we went through 18-26o and it liked better the 20, with the higher settings -even 26- not detonating but not helping the engine to rev fast through the rpms. If the whole setup of yours is handmade, please consider the following: I had a similar problem with a Golf G60 which I converted to turbo, as the piping and turbo sizing was made by me without any previous experience, I had a very similar problem in 5500 with the engine literally dropping in a hole without wanting to do anything until I backed off the gas pedal. Same as you free revving no problem, the cause was 1) to small turbo housing which in 5th gear and 5500 couldn't pass the gasses. I put a bigger one and oh! it was another car already. now the hole moved to about 6500 but hadn't any sense to enlarge it more because of the lag, so.. I adreesed my self to someone working with turbos for years and he started laghuing when he saw my setup. The problem after his guess was that I had a 180 turn in the turbine exit for the gases (with a very big radius though in my opinion like 4"). indeed this was the problem as I completely inverted the turbo so as the exit to come to the other side so as not forming a 180o turn and voila! every problem dissapeared in a magic way, letting me to thought that I could save the turbo housing that I changed, maybe it wasn't needed. That's all hope I help you for a little brainstorming..

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Dimitrios