tazman

I still have my factory cat also.

NZ951

The factory cat is not restrictive. It only has an influence if its clogged, I am not sure that the big fluctuations in your curve would be that promounced with a moderatley used factory cat.

Danno

Yeah, the US-spec cars with cats got the same power-rating as the Euro cars without catalytics. But over time, they do tend to melt and clog up the exhaust.

"I can tell you last time I looked at the AVC-R's duty cycle it is running 55% around 3500rpm and 86% around 6000rpm."

Yeah, I think it's the mechanical boost-control mechanism that's causing this boost-drop. The manual controller really only outputs a fixed duty-cycle based upon incoming boost-pressure. So at 19psi max-boost at 4500rpm, it sends a certain signal to the wastegate to open it. But at 5500rpm, it still sends this same signal. You need to back off pressure going to the wastegate as RPms increase in order to compensate for exhaust pressure. The GURU wastegate has a spring that's 2x as stiff as stock. Plugging in one as a direct replacement for the stock one will give 20-22psi of boost. So a controller is needed to turn it down. I think a 3x stiffer spring than stock would work better.

"I know you can adjust boost levels by 500rpm in the link, but how does that make for a flat curve?"

You may have a 47% duty-cycle at 4000rpm. Then program in 35% at 4500rpm, then 25% at 5000rpm, then 20% at 5500rpm. Something like this will reduce the wastegate opening in the upper-RPMs to compensate for exhaust-pressure.

gmonsen

Certainly the 300 number is great, but the exhaust is screwing you up. The turbo has its performance characteristics that will determine how quickly it will spool up, like blade angle of attack, weight, shaft balance and weight. Get a bigger pipe and gut the cat or get a race cat and you get on boost a lot lower. I think the boost spike up high looks like a wastegate issue and not anything with ignition. Also, where you get on boost isn't related to the wastegate or controller. While there are other factors, its basically the turbo and exhaust. If you do some pulls with just the downpipe, you get an idea of what you can do.

NZ951: You get the control and ability to hold a specific boost level by varying the duty cycle of the wastegate solenoid, which is either venting pressure to atmosphere or controlling a second gate port. I think the AVC-R and TiAL gate is a great setup. Add a big pipe and you're there.

Gordon

superjet.1

Those are impressive numbers for not having a cat bypass or digital boost controller. Put those in and youll s$#t your pants on what a differance itll make. Again congrats!!!

NZ951

You cant do that Danno.... You set the base and sens values, but no where for adjusting the duty cycle on the PCL files... unless I am missing a huge function of the software. Maybe I am?

Sam Lin

NZ, he's referring to setting the AVC-R, which has considerably more ability than the basic boost controller in your Link.

Sam

NZ951

Really so why did he quote me referring to my Link computer? How do you determine the ability of the AVCR having more ability than the link software? As its the software that control the boost essentially. The AVCR seems more manual if anything.

Sam Lin

Read dude, just read.

Sam

NZ951

Sam, did you read my post?

How do you think I came up with the question about varying the duty cycle with rpm? I take it you have never seen or used the link pcl file software.

JustinL

Well, It certainly looks like I know what I have to do to keep up now

What is the most cost effective method of electronic boost control? I don't think I need all the little features of the AVC-R, is there something more simple for a more reasonable price? Anybody got a used one for sale???

Justin

Danno

"Really so why did he quote me referring to my Link computer? How do you determine the ability of the AVCR having more ability than the link software? "

The EBC upgrade to the MAP-computers have the same functionality as the Link-1/2 standalone EFI boxes. Just that the Link-1 & 2 can be programmed from your PC. Run the PC-Link software, then pull down SETTINGS --> BOOST CONTROL and you get a 2D RPM-based table for programming duty-cycle in 500rpm increments. I'm running the C4-05113 version of the PC-Link software.

"What is the most cost effective method of electronic boost control? "

You can get your MAP-computer upgraded with the EBC feature for $100. It will actually control the stock CV to manage boost if you still have it. Otherwise, you can get an electronic boost-solenoid from BoostSciences for about $30. Another possibility is the ND solenoid used with the AVC-R controller.

NZ951

Sorry Danno, you only enter the desired MAP in that table, not the duty cycle... maybe you have an older version...

Danno

Hmm, ok. So you would enter higher map values (Kpa?) in the boxes which have dropping boost on the dyno.

NZ951

I just dont think that would help, I think the software would take the kpa from the MAP, say ok boost is not at desired level, and signal the solenoid accordingly, I would not think increasing values there would increase boost. A mate I went to Uni with wrote the software so I will ask him if you are interested.