Digital Tuning Question About Recent Tune

[03_Vortech_GT_Conv]

I was hoping someone might be able to provide a bit of info. I recently purchased a 03 GT Vert with a V3 Vortech Blower (pushing about 8 psi of boost).

I piped a CXRaxing FMIC, pullied down to a 3.33 (changed out for the next size down belt, etc.). Vehicle has new plugs and fluids throughout.

I recently sent it out for the my first dyno tune on the car (it did a respectable 365 hp and 355 tq). Since getting it back though I find that the vehicle is running rough right around 2300 RPM or so ... within 300 rpm or so. It's fine below and above that ... but if I hover right around there it feels almost like the car is missing.

The car idles well and pulls hard. Any thoughts would be greatly appreciated.

 

[squeak93]

Did you check all the clamps/connections for loose or blown off ones?

 

[03_Vortech_GT_Conv]

Did you check all the clamps/connections for loose or blown off ones?

Thanks squeak ... I did; that's usually my go-to. I have a set of fittings one side with tire valves on it. I pressurized the pipe and make sure it holds steady (listened and sprayed all the connections). Everything is tight. The system is making the boost i'd expect (where i'd expect to make it). I'm still running the stock intake (I don't have a powerpipe or anything yet). It's weird that it's missing in the same spot. I don't notice it during a pull, but then again I blow past there so fast I figure I wouldn't notice it anyway.

I notice it more when I'm cruising through my neighborhood slowly in second gear.

 

[03_Vortech_GT_Conv]

Thanks squeak ... I did; that's usually my go-to. I have a set of fittings one side with tire valves on it. I pressurized the pipe and make sure it holds steady (listened and sprayed all the connections). Everything is tight. The system is making the boost i'd expect (where i'd expect to make it). I'm still running the stock intake (I don't have a powerpipe or anything yet). It's weird that it's missing in the same spot. I don't notice it during a pull, but then again I blow past there so fast I figure I wouldn't notice it anyway.

I notice it more when I'm cruising through my neighborhood slowly in second gear.

It's running in that spot almost like as if the timing were off ... and I should say it's the stock Vortech intake ... lol

 

[a91what]

It could be a hiccup in the tune, call the tuner and ask if they will take a look.

 

[03_Vortech_GT_Conv]

It could be a hiccup in the tune, call the tuner and ask if they will take a look.

Thanks for the suggestion.

I gave him a call, and that was his thought too. I'll bring it by and he's going to tweak the tune.

 

[03_Vortech_GT_Conv]

One more thing on this. I'm relatively new to forced induction vehicles. After the intercooler was piped the vortech bypass valve is now pointing up, and I noticed a bit of a kink in the piping that returns to the intake. Based on the sound I'm hearing, I'm thinking I may be getting some compressor surge.

Please excuse the idiotic question, I know I need to eliminate that issue pronto ... but beyond that; my understanding was that surge would cause flutter only after closing the throttle ... not under power (at a low RPM range) ... am I correct in that assumption?

 

[squeak93]

I have a procharger but I had to eliminate the recirculation part. I was trying to push to much bypass air through the hose and back into the intake. Now that it's correctly venting to the atmosphere a lot of my issues I was chasing are now solved. (I have the big red race procharger valve)

To answer your question if you can't get the air out of the way it can still cause issues and flutter.

 

[03_Vortech_GT_Conv]

I have a procharger but I had to eliminate the recirculation part. I was trying to push to much bypass air through the hose and back into the intake. Now that it's correctly venting to the atmosphere a lot of my issues I was chasing are now solved. (I have the big red race procharger valve)

To answer your question if you can't get the air out of the way it can still cause issues and flutter.

Thanks squeak for the explanation, it makes sense. I have been contemplating getting rid of the recirculation part.

To do so I would need to switch up to a blow-through MAF to do so correct? My FMIC is piped with 2.75", as I undersand it I would need a MAF with the same diameter?