Did you eliminate your Secondary Throttle Vacuum System? - ZR-1 Net Registry Forums

RussMcB · 11-19-2017

One of the first things I did with my ZR-1 was to disable the secondaries, using chip mods by Haibeck. I was happy with the results. Simplified the system and the car ran well.

About a year later DIY Tune (aka Megasquirt) asked if they could use my car to try and finish up their MS3-Pro ECU for the LT-5. I said sure!

When they found out my secondaries were removed, they asked me if I could add them back in. I did, lent them my car, got it back a month later and it ran great. It was noticeably stronger. I'm sure that is because they had the luxury of running many iterations of tune and were able to reach an optimum tune.

They said they found that working secondaries helped the engine run better. I don't remember the details about why they believed that. My memory fails me. Perhaps it was the transition stage (a guess).

My hunch is, the computing power available today (compared to the late 1980's) allows them more control over the injectors and butterflies.

I'm certainly not knocking the removal of secondaries. I'm just sharing this experience to the thread.

View Poll Results: Did you eliminate your Secondary Throttle Vacuum System?
Yes.	21	55.26%
No.	17	44.74%
Voters: 38. You may not vote on this poll

11-19-2017	#11
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: Did you eliminate your Secondary Throttle Vacuum System? One of the first things I did with my ZR-1 was to disable the secondaries, using chip mods by Haibeck. I was happy with the results. Simplified the system and the car ran well. About a year later DIY Tune (aka Megasquirt) asked if they could use my car to try and finish up their MS3-Pro ECU for the LT-5. I said sure! When they found out my secondaries were removed, they asked me if I could add them back in. I did, lent them my car, got it back a month later and it ran great. It was noticeably stronger. I'm sure that is because they had the luxury of running many iterations of tune and were able to reach an optimum tune. They said they found that working secondaries helped the engine run better. I don't remember the details about why they believed that. My memory fails me. Perhaps it was the transition stage (a guess). My hunch is, the computing power available today (compared to the late 1980's) allows them more control over the injectors and butterflies. I'm certainly not knocking the removal of secondaries. I'm just sharing this experience to the thread. __________________ Russ McBride, [COLOR="Red"]Car Sold 8/2020[/COLOR] #1635, Marietta, GA USA, 1991 ZR-1, #766 (bought 1/1/2015) MS3-Pro, OBX, SW X-Pipe, Borla, Hurst, SLP, Goodyear F1 GS-D3, Kenwood. HOTB 2016Q3 [IMG]http://zr1.net/forum/picture.php?albumid=316&pictureid=2873[/IMG] [IMG]http://zr1.net/forum/picture.php?albumid=336&pictureid=2985[/IMG]