SLP DD TVS2300 issue and resolve
07-27-2014, 01:10 PM
#1
On The Tree
Thread Starter
Join Date: Aug 2011
Location: Indiana
Posts: 187
Likes: 0
Received 0 Likes
on
0 Posts
SLP DD TVS2300 issue and resolve Since going to a 3.2" pulley and 10 psi on my TVS I have on occasion had a situation on rapid 2-3 and/or 3-4 shifts (no power shifts) where it would develop a high boost condition to 20+ psi until I could react and lift the throttle. Of course the AFR was all over the place and I was afraid of mucho damage, spark blowout & KR ensued, ect.
Logs showed the throttle was not oscillating, just the boost was very high. Looking at the design of the SLP internal bypass valve (BPV) I realized upon testing that there was no dampening on the vacuum actuator at all. As soon as vacuum was released it would slam open. When boost builds I presume it slams shut the same way. The design is such that the BPV opens to recirc the blower as soon as the intake is in vacuum and closes as soon as vac drops to near zero allowing boost to build. I suspect that in extreme cases the 'bounce' of the actuator slamming was producing the boost issue, perhaps by causing it to stick shut or oscillate open and shut rapidly? I'd need a high speed camera under the hood to know I guess.
My solution was to insert a restrictor in the vacuum line to the BPV actuator. I have a .030 welding tip I used as an experiment and found that now instead of slamming shut entering boost it takes ~.4 sec to go from full vac to full boost. A little slow so I will try a .045 restrictor next time out hoping for about .2 sec but the problem is solved. I ran it through the gears 4-5 times this morning without issue.
I'll try and post some log screen shots. Hopefully this can help others if they encounter the same situation.
Logs showed the throttle was not oscillating, just the boost was very high. Looking at the design of the SLP internal bypass valve (BPV) I realized upon testing that there was no dampening on the vacuum actuator at all. As soon as vacuum was released it would slam open. When boost builds I presume it slams shut the same way. The design is such that the BPV opens to recirc the blower as soon as the intake is in vacuum and closes as soon as vac drops to near zero allowing boost to build. I suspect that in extreme cases the 'bounce' of the actuator slamming was producing the boost issue, perhaps by causing it to stick shut or oscillate open and shut rapidly? I'd need a high speed camera under the hood to know I guess.
My solution was to insert a restrictor in the vacuum line to the BPV actuator. I have a .030 welding tip I used as an experiment and found that now instead of slamming shut entering boost it takes ~.4 sec to go from full vac to full boost. A little slow so I will try a .045 restrictor next time out hoping for about .2 sec but the problem is solved. I ran it through the gears 4-5 times this morning without issue.
I'll try and post some log screen shots. Hopefully this can help others if they encounter the same situation.
Last edited by Iam Broke; 07-27-2014 at 01:43 PM.
