So I boosted my car and went with a nistune setup all at once. I have a 95 240sx with a ka-t and a t25 sr turbo. The turbo is clearly too small for the engine but it's what i have. The car builds boost remarkably fast, and I could be seeing full boost by 1400rpm. I tend to build boost at very low throttle angles and as such I now generally drive it with a very light foot to hold it back.
When shifting the car at those light throttle angles the rpm tends to drop so insanely fast that I am slamming through the gears and find it near impossible to consistently rev match. This is very rough and I am sure hard on the car.
Is there something I can do with my tune to help compensate for this phenomenon? any tips? (other than get a bigger turbo) Some sort of decel delay at low rpm or throttle? Looking for tips.
low throttle angle rpm drops WAY too fast, small turbo car
Moderator: Matt
Re: low throttle angle rpm drops WAY too fast, small turbo car
have a look at decel timing tables.
Maybe checking mixtures when you shut throttle will give you more clues.
(enrichment is an upshot of fast throttle close action, check that BOV recirculation is responding quickly enough).
If your speedo isn't working, this can prevent decel injection cut from occuring.
maybe lifting the rpm in which this occurs will help the engine recover earlier combined with a gradual ign timing drop.
Maybe checking mixtures when you shut throttle will give you more clues.
(enrichment is an upshot of fast throttle close action, check that BOV recirculation is responding quickly enough).
If your speedo isn't working, this can prevent decel injection cut from occuring.
maybe lifting the rpm in which this occurs will help the engine recover earlier combined with a gradual ign timing drop.
Re: low throttle angle rpm drops WAY too fast, small turbo car
In addition to the above, are you using a BOV? Is it plumbed back pointing to the turbo. Any reversion hitting the AFM backwards can cause overfuel spikes and also cause stalling