Lag and loss of boost between shifts

[Ajmalian]

Hey guys,

I'm kinda new to this so please try and bare with me. I have an SS with a 2.9L whipple s/c and a stage 2C cam from Livernois. My car is a 6 speed manual and the problem I seem to face is that I tend to lose quite a bit of boost if not all during my gear changes...and I mean during fast shifting during races or aggressive driving. There seems to be a significant lag of some sort in the supercharged boosted power return when shifted into the higher gear. Anybody else facing this problem? Any idea what it is and how this could be solved?

I look forward to your feedback. Any help would be appreciated.

[SUKXOST]

check with your tuner. See if the fuel is being commanded too late....my last tune did the same thing and a new tuner fixed it by having the fuel shifted to the left/earlier.

[Chris@Livernois]

Originally Posted by Ajmalian

Hey guys,

I'm kinda new to this so please try and bare with me. I have an SS with a 2.9L whipple s/c and a stage 2C cam from Livernois. My car is a 6 speed manual and the problem I seem to face is that I tend to lose quite a bit of boost if not all during my gear changes...and I mean during fast shifting during races or aggressive driving. There seems to be a significant lag of some sort in the supercharged boosted power return when shifted into the higher gear. Anybody else facing this problem? Any idea what it is and how this could be solved?

I look forward to your feedback. Any help would be appreciated.

Who tuned the car for you?

[Ajmalian]

Originally Posted by Chris@Livernois

Who tuned the car for you?

My tuner...at a garage here in Dubai by the name of DynoKing. Why do you ask who tuned my car?

[Andy@Livernois]

Originally Posted by Ajmalian

My tuner...at a garage here in Dubai by the name of DynoKing. Why do you ask who tuned my car?

I am sure chris was making certain the car indeed was dyno tuned, rather than using the standard whipple tune. Unfortunately, I do not think it is going to be something we can figure out without having the car here. It will need to be recreated on the dyno, or while datalogging it to sort that out, that will tell you if it is tune, or mechanically created.

[Ajmalian]

Originally Posted by Andy@Livernois

I am sure chris was making certain the car indeed was dyno tuned, rather than using the standard whipple tune. Unfortunately, I do not think it is going to be something we can figure out without having the car here. It will need to be recreated on the dyno, or while datalogging it to sort that out, that will tell you if it is tune, or mechanically created.

Hey Andy,

I was told by my tuner that it was a common problem in Whipple sc and its apparently the bypass valve which causes this problem. He's worked on many Camaros with Whipples, mostly automatics (lucky bastards don't lose boost during gear changes!! ) and it's usually an odd one here and there in the manual ones where the car doesn't seem to have this lag or delay issue. Now the issue also is the fact that we are in UAE. If I were in the US, I would've personally driven down to you guys and let you have a look. Also, unfortunately I'm not very good with technical terms but what basically it feels like when shifting hard and fast, is that when you get back on the gas, the power comes back (NA kinda power) but there is literally almost a 1 second, if not more before you can feel the boost punch back in.

I'm not saying I'm the best shifter there is but I know I can shift well enough and what's upsetting is that I am rating at 608 RWHP and a mildly modified, automatic CTS-V coupe rating at 548 RWHP on the very same dyno handed my a$$ over to me just because I was losing boost during shifts... He would inch up or rather metre up every time I shifted..

So is there anything we can do at our end to diagnose the situation or perhaps send some kind of logs or observations across to you so as for you to possibly study and analyze what the problem is?

[Andy@Livernois]

maybe see if your tuner can send you a data log of the situation? it would be interesting to see what is going on during this.

BTW, you wouldn't be the first person to ship his car from that region to have us tune/perform work on their car but I do realize that is an unlikely scenario. See if he can give you a data log.

[simon.w]

If you think it is the actuator opening the bypass valve between shifts, you could try a restrictor in the vacuum line. Mine was having the opposite issue because of the lack of vacuum with my big cam ... closing too quickly on accel. Mike at Whipple sent me the restrictor which fixed the issue. Initially the hole was too small, which created what was almost like turbo lag ... so I got a tiny drill bit set and opened up the hole slightly. Now it's perfect.

There's no reason why it wouldn't work in reverse ... slow the opening of the valve.

It is a 1" long step-tapered cylindrical brass that pushes into the vacuum pipe on the actuator, with a tiny hole in it. Looks a bit like a jet out of a holley carburetor that has been stretched. (minus the thread and screwdriver notch)

[bct10985]

Pm Ayousef, he seems to know a lot of technical info and has a Whipple. I think he is from Dubai also

[Ajmalian]

Originally Posted by bct10985

Pm Ayousef, he seems to know a lot of technical info and has a Whipple. I think he is from Dubai also

As funny as it may sound bro....Yousef is the guy who owns the garage in partnership with my tuner where I got all the jobs carried out in my car. That is if we are talking about the same Yousef. Yousef Al Matar??

[TOSTO RACING]

Originally Posted by Ajmalian

Hey Andy,

I was told by my tuner that it was a common problem in Whipple sc and its apparently the bypass valve which causes this problem. He's worked on many Camaros with Whipples, mostly automatics (lucky bastards don't lose boost during gear changes!! ) and it's usually an odd one here and there in the manual ones where the car doesn't seem to have this lag or delay issue. Now the issue also is the fact that we are in UAE. If I were in the US, I would've personally driven down to you guys and let you have a look. Also, unfortunately I'm not very good with technical terms but what basically it feels like when shifting hard and fast, is that when you get back on the gas, the power comes back (NA kinda power) but there is literally almost a 1 second, if not more before you can feel the boost punch back in.

I'm not saying I'm the best shifter there is but I know I can shift well enough and what's upsetting is that I am rating at 608 RWHP and a mildly modified, automatic CTS-V coupe rating at 548 RWHP on the very same dyno handed my a$$ over to me just because I was losing boost during shifts... He would inch up or rather metre up every time I shifted..

So is there anything we can do at our end to diagnose the situation or perhaps send some kind of logs or observations across to you so as for you to possibly study and analyze what the problem is?

I experienced the same thing tonight at the track its bad in my car almost feels like i shut the key off, I even powershifted the car and never let off the gas anyone ever figure this out I have a whipple also and cam etc?

Car doessn't seem to do it on the street at all which has me stumped only at the track where it is hooking everytime???

I'm pretty bummed out my car is running like a cam only car Hopefully there is a fix out there