Engine bogging down with any swift throttle change

Rotary Evolution · 04-27-2013, 05:08 PM

it's less of a problem on stock cars, the Rtek puts more dependence of tuning on the pressure sensor for the lookup tables for load, the stock ECU mainly uses it solely for timing advance.

i have also seen similar results on many cars without a restrictor in the line, even running the pressure sensor as far up stream as possible you sometimes will get resonant spikes in the readings. the Rtek was actually showing a bounce of between 5"Hg and 2psi under WOT full load off the stock port by the ACV on a non turbo car. the readings smoothed out from a 7"Hg bounce to 3-4"Hg bounce by moving it to the throttle body, installing the factory restrictor lowered it to less than 1"Hg fluctuation.

on some cars even with a standalone on turbo engines i have seen 2-3psi fluctuations even locating the source line at the port i mentioned near the throttle body, i always recommend an orifice located near your map sensor to filter the signal. i suspect this also may be due to some lax filtering of the signal on the ECU side of some manufacturers. those were cars that had either no boost controller or manual boost controllers equipped, wastegate cycling was not the cause.. the result was AFRs bouncing from perfect to 1-1.5 points lean.

RETed · 04-28-2013, 02:05 AM

Quote:

Originally Posted by Rotary Evolution

on some cars even with a standalone on turbo engines i have seen 2-3psi fluctuations even locating the source line at the port i mentioned near the throttle body,

I've never had a problem with this, especially with Haltech systems.
I blame this on a badly tuned fuel map (at idle).

-Ted

Rotary Evolution · 04-28-2013, 09:09 AM

Quote:

Originally Posted by RETed

I've never had a problem with this, especially with Haltech systems.
I blame this on a badly tuned fuel map (at idle).

-Ted

how does a poor fuelling map translate to 2-3 psi fluctuations at 10-15psi @ 11:1 AFRs? note i mentioned it wasn't a common problem but something i have noticed before on a few cars. if the cars were misfiring due to overly rich conditions in the sub 10's i would tend to agree.

04-27-2013, 05:08 PM	#1
Rotary Evolution rotaryevolution.net Join Date: Feb 2011 Location: Las Vegas, NV Posts: 248 Rep Power: 15	it's less of a problem on stock cars, the Rtek puts more dependence of tuning on the pressure sensor for the lookup tables for load, the stock ECU mainly uses it solely for timing advance. i have also seen similar results on many cars without a restrictor in the line, even running the pressure sensor as far up stream as possible you sometimes will get resonant spikes in the readings. the Rtek was actually showing a bounce of between 5"Hg and 2psi under WOT full load off the stock port by the ACV on a non turbo car. the readings smoothed out from a 7"Hg bounce to 3-4"Hg bounce by moving it to the throttle body, installing the factory restrictor lowered it to less than 1"Hg fluctuation. on some cars even with a standalone on turbo engines i have seen 2-3psi fluctuations even locating the source line at the port i mentioned near the throttle body, i always recommend an orifice located near your map sensor to filter the signal. i suspect this also may be due to some lax filtering of the signal on the ECU side of some manufacturers. those were cars that had either no boost controller or manual boost controllers equipped, wastegate cycling was not the cause.. the result was AFRs bouncing from perfect to 1-1.5 points lean. __________________ http://rotaryevolution.net Last edited by Rotary Evolution; 04-27-2013 at 05:17 PM.