Closed loop boost control

Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.

Moderators: The Dark Side of Will, Series8217

Post Reply
CincinnatiFiero
Posts: 2908
Joined: Thu Dec 20, 2007 2:47 pm
Location: Columbus, Ohio

Closed loop boost control

Post by CincinnatiFiero »

Turbotech, not Fierotech, but it'll be fine.

I own a fair number of turbo cars, but most of them are factory turbo cars that I haven't modified, so pardon my ignorance.

I was watching a video on Haltech's youtube channel about closed loop boost control and holding a wastegate shut longer to decrease turbo lag and increase power under the curve.

https://www.youtube.com/watch?v=2ZpCYe_0Azs

The results are pretty impressive, on a ~310HP car they saw gains of around 20HP throughout the range, and on a higher boost setting they saw up to 60HP gains.

I do not have Haltech, nor do I have standalone. But GFB (and many others I'm sure, GFB happens to get good reviews and the price is good) offers an electronic boost controller that claims to do closed loop boost control.

Are any of you running an electronic boost controller? On my Skyline I have always thought the car was laggy, and was curious if I could employ this technology to make the car more responsive. Car currently has a turbonetics bleed valve on it, but its wound all the way shut because the car has 1bar wastegates on it and ~15psi is all the more I wanted to run untuned (have a Blitz chipped ECU in the car). The car does NOT have stock ceramic turbines on it, it has larger than stock steel wheeled twins.

This is a long post, but basically what I'm asking is, could I see any increase in response using an electronic boost controller on turbos operating at their wastegate pressure? Or does this strategy only work with a custom tune and running boost pressures above wastegate pressure.
User avatar
Shaun41178(2)
Posts: 8358
Joined: Fri Nov 19, 2004 7:12 pm
Location: Ben Phelps is an alleged scammer

Re: Closed loop boost control

Post by Shaun41178(2) »

Short answer is yes it can help with spool. Even with your stock or modified turbos and 15 lbs wastegate springs you can see better spool at lower rpm and higher loads like 4th or 5th gear

I think there are reasons for this however. Ebcs need additional vacuum lines. These vacuum lines need to be pressurized by the turbo. This time allows the wastegate to stop from cracking open before target boost is reached. This adds tq as spool is increased.

A cheap way to help spool without an ebc is to change the reference point to the wastegate. I am assuming that your upgraded turbos have their boost reference line directly off the turbo. Yes? What you can do is move that reference line on the opposite side of the intercooler just before the throttle body/bodies as I think you have itbs

So lets say your wastegate started cracking open at 8 psi, your compressor housing on the turbo sees 8 psi before the tb sees it due to pressure drop through the intercooler and piping itself. Move your wastegate signal off the compressor housing and now 8 psi at the tb might be 10 psi at the turbo compressor housing. Its not much but its a gain in response.

I have my wastegate fed off my plenum before my itb butterflies.

This videos shows 4 boost controllers on a skyline and the response. It looks quicker for sure with the ebcs.

https://youtu.be/LZWpdww8XdE
The Dark Side of Will
Peer Mediator
Posts: 15610
Joined: Wed Nov 24, 2004 11:13 pm
Location: In the darkness, where fear and knowing are one
Contact:

Re: Closed loop boost control

Post by The Dark Side of Will »

The vacuum lines don't impact spool times.

Moving the reference connection is a good idea.

Electronic boost controllers have been better than mechanical boost control ever since the Greddy Pro-Fec B days of the early '00's. Modern digital ones are probably better, as the PFB was an analog system. It included an adjustment to balance how rapidly boost came up vs. how much overshoot of the baseline boost level you were comfortable with. For example, if you're targeting 15 psi, the adjustment could get you there quicker if you allowed a transient overshoot to 17 psi, with the level quickly dropping back to 15.

Any external boost controller is going to be fairly primitive compared to ECU boost control.
CincinnatiFiero
Posts: 2908
Joined: Thu Dec 20, 2007 2:47 pm
Location: Columbus, Ohio

Re: Closed loop boost control

Post by CincinnatiFiero »

I am looking at running Nistune for programmable engine management and I do not know that Nistune supports a boost control solenoid.

I also don't know that I am ready to go to Nistune yet, so I was considering buying that GFB product in the meantime if I will get a noticeable improvement out of it. If I go Nistune and they support a boost control solenoid now, or I go with Haltech or similar that does, I could always move the GFB unit to my GTFour, dads Soarer, or the GTS Skyline I have enroute.

Right now my GTR is taken apart, I am port matching the stock turbo manifolds to the larger inlets on the N1 Turbos that are on my car, and I am fitting larger turbo outlets to the turbos. Both of those things should help the car come on a little faster as well.
User avatar
Shaun41178(2)
Posts: 8358
Joined: Fri Nov 19, 2004 7:12 pm
Location: Ben Phelps is an alleged scammer

Re: Closed loop boost control

Post by Shaun41178(2) »

You could always try a cheap manual controller as well and see if that helps.

I would change your wastegate reference line though. Cheapest option and will show gains
Post Reply