I thought about making a poll, but I prefer to see some of the more detailed experiences those who've upgraded to the 90mm Magnusson J-tube. Weather the kit was purchased from us or pieced together elsewhere, sharing any and all feedback will help us and future customers decide on the benefits of this mod.
As of yet I don't believe anyone has solved the WOT issue that the '03-'05 trucks are experiencing. And the '06 and later trucks have a similar issue but require a different fix as they don't use a TAC module. It would be great to see results of some of the early '02 vehicles that aren't experiencing the WOT issue and how they run compared to the '03 and later trucks. It appears that the approach to the WOT issue is being dealt with in two different manners. I understand HP Tuners is working on a look up table that can rescale the throttle voltage values to allow 100% WOT. (I like this approach the best). The second method is to build an electronic converter that will output the proper voltage.
I'd also like to know about any idle and part throttle experiences good and bad. Some may be tuning related and some may not. Also is there a felt difference in overall response? If so, please comment and include your engine size and if any retuning was done or needed. Obviously any before and after dyno data and track times will be very helpful.

Thanks in advance for all your input. I really appreciate all your support.

Richard

 

This is for a cable TB, not sure if that's the kind of feedback you were looking for but I'll throw it in anyway.

I did the conversion at the same time as my motor/tranny swap, so I don't have good before and after conparisons unfortunately. I used a Nick Williams 90mm TB, told him it was for a truck, and the butterfly cam came notched correctly. F8LZ71 used an F-body Nick Williams TB, and he had to modify the throttle cable mount to get it to fit correctly.

The Nick Williams 3-hole TB almost fits the Radix j-tube, had to elongate the two bottom holes a bit. The cruise control cable mount is different as well, I ended up buying a non-ETC '02 F-body cruise control cable assembly for $35 from the dealer and removing the plastic clip and reinstalling on my cruise cable. I wish I had good before and after data, but with all the other changes it's not a good comparison.

 

I did the 90mm conversion from WCCH on my '03 SSS 6.0 LQ9. No idle issues at all, works flawlessly at idle. Part throttle after the 90mm conversion somehow changed my shifts points. my truck shifts later than it did before. i noticed this immediatly after doing the conversion. I did not notice any SOTP gains from doing this mod, though my throtle response in general is slightly better. I have not had any dyno or 1/4 comparisons yet. I did not notice ANY drop in IAT's either. Did not gain or lose any boost either. Tunning done before and after 90mm by zippy. WOT, the tb blade only opens to approx. 85%

 

Just a head up about the TPS issue, we are working on this problem every day. I hope to see a fix soon.

 

 

Huh? I have a TAC module don't I? What did I pull out and swap in place the TAC module you supplied? My experience is that, with a complete kit supplied by you, as soon as I go WOT the truck goes in to reduced power mode... and 3 codes pop... I started a thread on it... a search should find it and the codes. My truck is a daily driver so I don't have time to jack with the 90 setup on the truck. I have someone willing to help me on this issue but I need to provide a complete signal pinout from the PCM to the TB including the TB adaptor. I seriously doubt I will be first to the finish line with a fix for the 06's that is why I am hopeful that current folks working on this issue will get there in due time. I'm in no hurry... but would like to enjoy my 90 setup sooner rather than later...

Bill

 

I'm glad I waited on this mod.

Jim

 

Thanks for the input so far everyone.

My bad Bill. In a brain fart I was thinking truck instead of C6 Vette (or vise versa). If the TAC module I sold you won't work for your application, I'll swap out to one that will. I'm a bit suprised GM still insists on a TAC module for the '06 trucks. The Vettes are controlled by the PCM directly.

Holty, I believe the shift points are commanded by vehicle speed and throttle postition. If the throttle position is in fact being miss reported then the shift points will indeed change. Once a fix is found, this should return back to normal.

Richard

 

Thank you sir We gotta get this 90 setup working... I have a M122 I want to buy... and start building a forged block... and save for a 4L80E... and a diff... brakes to stop it all... and so on

Bill

 

I did the WCCH J-tube/90mm TB conversion on my 2005 5.3L Truck.
No idle issues . Part throttle after the 90mm conversion is also good. It changed all shifts points. The truck shifted later than it did before. I did notice Some gains, throttle response is slightly better. there is slightly more gms/sec airflow and a small but messurable drop in IAT's.

I noticed that the actual TB only opens about 85% at WOT.
I also noticed while watching my scanner that the scanner indicates the TB at 100% at about 75% throttle pedal and if you push the throttle more there is no change to the TB opening or scanner readings.