Death on sudden opening of throttle

[Bruce Plecan]

>Too much air? More fuel won't help. Is the intake just flat out too big?
>
>TK

Too big of butterflies play hell with cylinder filling, as they open.
Try dropping (maybe adding) some timing as they open.
For more/better help might send more data.  Eng cid/butterfly
size plenum vol. cam CR, all those little things that add up.
Not saying can pull the answer outta air, but maybe be able to better
help.
Cheers
Bruce


>-----Original Message-----
>From: Tony Bryant <Tony.Bryant at psc.fp.co.nz>
>To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>Date: Sunday, June 28, 1998 10:51 PM
>Subject: Death on sudden opening of throttle
>
>
>>I've finally rebuilt my intake system (welded up from steel exhaust 
>>tubing), but I've got the following problem:
>>
>>When the throttle is mashed at lowish RPMs i.e. <2000RPM
>>the engine dies for about 1/2 - 1 second, before getting its
>>act together and then pulling strongly. 
>>
>>Sounds like not enough throttle enrichment you say... Not so, 
>>I've tried enough enrichment to sink a battle ship, and no
>>noticeable difference (just get lots of black smoke). I've tried 
>>from no enrichment, way upto pegging the injectors at 16ms per 
>>injector per cycle (100% VE requires only about 7ms)
>>
>>My setup has a second set of injectors mounted on the runners,
>>if I switch to use these a the primaries the problem gets much 
>>worse. This indicates to me its something like fuel dropping out 
>>of suspension.
>>
>>Changing the injection timing (Sequential system) does help a little, 
>>but not much.
>>
>>FYI: I've got a reasonably small cam in it : 255deg @ .006", 40 deg 
>>overlap.
>>
>>FYI: I sample the revs & MAP sensors 16 times a second, so its not an 
>>ECU response problem.
>>
>>Q. Whats happening here? Theories anyone?
>>
>>Q. Do other people here have this problem? Whats the solution?
>>
>>Cheers.
>>
>
>