Discuss all things tuning in this section. News, products, problems and results.
hey guys ive built a 4cyl N/a engine with high comp pistons and made an ITB manifold. I had decided to blank off all the vacuum ports and switch the microtech ECU to the TPS tuning option (which doesn't use the MAP sensor at all). The problem I have is that at only a touch of the throttle, lets say 5%, the rpm greatly increases. I can understand this is due to 4x throttle bodies letting in a lot of air. but on HWY driving... it doesn't really matter if your at 60% throttle or 100% it just goes... I cant really see how the ECU gets a load signal from the engine if its only using TPS... I mean on a flat road it would work well, but what about going up or down a big hill?
its being difficult to tune, should I just hook up a vacuum box to all of the throttle bodies and use the map sensor function instead of only TPS? would that be easier to tune?
also can anyone recommend runner lengths and diameters and how they affect top end? im looking for top end power 5000-8000
TPS will work far better than MAP in almost all ITB engines. Im not sure how configurable the Microtech is but typically you want to configure your load axis break points so that you have fine resolution at small throttle openings where airflow can change dramatically with a small throttle angle change, then at larger throttle openings you can have much larger jumps. So for instance typical TP break points I use might be something like 0%, 2%, 4%, 7%, 10%, 15%, 20%, 30% 50%, 70%, 100%.
As for runner length, every engine is different, but a good place to start that works pretty well on a wide range of engines is 300mm measured from valve seat to trumpet face.
hey Adam thanks for the reply. ill give it a go