Katech 103mm throttle body control

[ccrp]

Has anybody played much with the 103mm throttle bodies and their response?

have one on my stock cammed LT1 with headers/MSD/ported heads and throttle response up is great, but it is slow in coming down. It doesnt hang it is just slower coming down.

in the old days that would playing with RAF but those tables dont exist in a torque based control anymore. Played with DD tables but it doesnt seem to have much effect at all.

throttle body area limits has been set to 7250 (caluclated from size minus shaft).

where to start it making it snappier on the way down?

[Mez]

Has anybody played much with the 103mm throttle bodies and their response?

have one on my stock cammed LT1 with headers/MSD/ported heads and throttle response up is great, but it is slow in coming down. It doesnt hang it is just slower coming down.

in the old days that would playing with RAF but those tables dont exist in a torque based control anymore. Played with DD tables but it doesnt seem to have much effect at all.

throttle body area limits has been set to 7250 (caluclated from size minus shaft).

where to start it making it snappier on the way down?

What is ignition advance doing at off idle RPM to 2800?

[MIKE91B]

I have been trying to confirm a solution for this but have not had much time to play. My first though is the external load table in the idle window. With torque being calculated by air flow, lowering the torque values in the higher rpm ranges in this table may command the throttle to close faster when returning back to idle. That table uses RPM and engine oil temp and remember that there is a lot of other tables in the idle window that are effecting engine warm up etc etc. I would start by lowering the negative values only and above 1200-1500 rpm. I would think lowering it by 5% at a time would be a good starting point. Let me know what you find. Watch the torque command and see if it is actually commanding less when you apply the reduction as in my mind that will tell you if you are actually effecting the command. If I find out anything else ill be sure to share it.

[MIKE91B]

Played with this a little bit last night and think I made some headway. I did notice a slightly faster return to idle with the before mentioned changes. I'll be straight forward and and say this was by no means a giant leap. I didn't have the chance to go as far as I would have liked. I referenced the tables from a gen 5 zo6 and adjusted only the 1600+ negative values. Im now curious if the added volume of the LT1 throttle body will require more aggressive torque reduction on the smaller L83, relative to the LT1. Still not sure if I see delivered tq dropping any more than normal. that's all I got as of now.

[MIKE91B]

Well you can scratch my idea. After further testing I have come to the conclusion that my recommendations did nothing to correct the issue. I don't have any good ideas as of now but if that changes I will post them. You live you learn and the E92 wins again.

[ccrp]

i got it sort of done with increasing negative values in DD table. A big difference made entering -7 in DD in the 0/0 cell. Not it returns nicely with no hanging....

[GrannySShifting]

Has anybody played much with the 103mm throttle bodies and their response?

have one on my stock cammed LT1 with headers/MSD/ported heads and throttle response up is great, but it is slow in coming down. It doesnt hang it is just slower coming down.

in the old days that would playing with RAF but those tables dont exist in a torque based control anymore. Played with DD tables but it doesnt seem to have much effect at all.

throttle body area limits has been set to 7250 (caluclated from size minus shaft).

where to start it making it snappier on the way down?

How did you calculate this?

Stock is 90mm @ 6362, ecu value is 74% of that or around 1650 less at 4704
103 is @ 8332 74% being 5832, or if you want to say shaft size is the same, plus the extra distance it has to span which is most logical would be 1888 less than calc =