×

Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

VE spike at 2500RPM 100%TPS

General Tuning Discussion

Forum Posts

Courses

Blog

Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads

Author
386 Views

Hi, No matter how much testing I get a VE spike at 2500RPM 100%TPS see zero "0 kpa" MGP row. I put in new columns in the VE table for my MX5 NB2 to narrow the spike down. So at 100%TPS, the VE goes from 69.4% at 2250RPM to 82.0 at 2500 and back to 71.4 at 2750, see screenshot. The VE can't shift that much as far as I know. The VE curve is otherwise smoothish so the 2500RPM blip doesn't make much sense to me. Could this be an injection issue where the injectors just don't deliver at that RPM or something else like the extrators (headers) I put on, burnt valves...? Thanks

Attached Files

That would usually be, if it's a true condition, down to a resonant frequency, or series of interacting frequencies, somewhere that cause a spike in cylinder filling and/or a critical frequency within the fuel rail that drops fuel pressure at that point.

As Gord mentioned, this is possible it's based on the actual engine behavior/airflow, but it could be the result of a quirk in the fuel system or something else. I love that you're questioning it Chris.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?