45 replies to this topic

[Dave E]

That option has not been overlooked

[Duncan VXR]

Now the audi v6 tfsi 3.0 supercharged conversion I could accept in the vx 450 bhp without opening engine and sounds like a v8 with decent exhaust DG

[Dave E]

So could I however, regrettably, I don't have enough spare internal organs/ limbs to pay for it

[CraigyT]

I have run a garrett on standard management for 4+ years. Started off with a gt2860 and then changed to a gt2871. Personally the 2871 is far better further up the Rev range with better torque and the difference down low is hardly even noticeable so I would Defo go for a 2871. I run the standard management but use a apexi avc-r boost controller so i can easily adjust how the boost comes in with the touch of a few buttons. It also has the option for gear based boost. Such as 0.6 bar in 1st and 2nd then 1 bar or whatever in 3,4,5. I'm only on vxr injectors and they are at their limit. but at 1 bar of boost it makes 330 bhp with same torque.

[Bumblebee]

That's interesting that you have a boost controller as I've been told By a lot of company's that I can't run one on std management, can't remember why now though........

[Ormes]

That's interesting that you have a boost controller as I've been told By a lot of company's that I can't run one on std management, can't remember why now though........

Control of AFR?

[CraigyT]

It's no problem to use a boost controller.
You just need to leave the standard boost solenoids plugged in electrically.

Pic is a bit messy as I had the dash apart when fitting.

[Cookies220]

So does this smooth out power delivery on part throttle CraigyT?

[CraigyT]

Sorry,not sure what you mean by power delivery on part throttle? I would have thought that depended on how much you are pressing the pedal?

[P11 COV]

Sorry,not sure what you mean by power delivery on part throttle? I would have thought that depended on how much you are pressing the pedal?

 

On a stage 4 turbo with the standard turbo (300bhp ish) it is fine when accelerating hard (full throttle) and obviously when off throttle, but when you need to balance the throttle (hold a steady speed/boost) it can dump the boost/boost/hic up/chatter, basically not be very smooth and controllable.

 

I find if I accelerate with the throttle say 30/40% open it gets to a certain point in the rev range when it just dumps boost momentarily causing a hiccup in the acceleration. The only way to circumvent that is to adjust the throttle. 

 

The question is, with the Garrett is that the case or not?

[doctorfrag]

I've only had my stage 4 for a short time but this is exactly the issue I have or should say had until the chargecooler went! You cannot moderate part boost and hold it. I've been looking at the threads regarding turbo stall and it seems Nevs mod of adding an external dump valve is a good solution, also at hornet suggest using an HKS boost controller also. All other turbo cars I've had it was possible to hold the cars boost at 1 bar 1.2 bar whatever depending on the throttle so I'm sure this would be possible on this engine. I want to be able to hold constant torque to the rear whilst negotiating bends otherwise I'm going to spin if I don't get this sorted, so I'm going to do Nevs mod first off before thinking any further. Joe

[doctorfrag]

Should of said at Thorney!, this will teach me to post from a phone

[CraigyT]

Ah I see. No that's not the case for me personally, it holds boost fine. Next time im out a drive I could film it I guess so you can see. Surely that would be down to boost control and not the actual turbo?

[doctorfrag]

Hi, presumably you've got a dump valve with your garret turbo anyhow as you wouldn't have the old diverted valve? Sorry I'm new to the car so not sure of the exact plumbing! Joe

[P11 COV]

Ah I see. No that's not the case for me personally, it holds boost fine. Next time im out a drive I could film it I guess so you can see. Surely that would be down to boost control and not the actual turbo?

 

Yes...I would guess its the result of the recirculation (internal dump) valve just being open or shut and not being able to modulate that finely enough?

 

The issue is that at oem levels of boost its is fine, and at 230 -250 bhp (stage 2/3). It seems to be at stage 4 levels it becomes an problem.

Edited by P11 COV, 03 September 2014 - 10:15 PM.

[CraigyT]

no dump valve installed. Just lots of chatter👍

[YorkieAndrew]

I've only had my stage 4 for a short time but this is exactly the issue I have or should say had until the chargecooler went! You cannot moderate part boost and hold it. Joe

Me too. Pleased to read i'm not alone. Fantastic on full throttle though

Edited by YorkieAndrew, 03 September 2014 - 10:29 PM.

[Dave E]

There are two issues, one is the inability to select and hold a desired boost level. The other is the inability to dump part boost, it's all or nothing and unfortunately one compounds the other. Accelerating up to 0 psi is obviously no problem, it is then possible, with a delicate touch, to select between 0 -10psi but this is where the problems start. ANY further pressure on the throttle pedal will see full boost, end of. Doesn't matter how light you are on the throttle, that's it. So what happens is when you reach the tipping point, all of a sudden you find yourself on full boost so naturally you lift a little but because it'll only dump all or nothing your then fully off boost. This ain't subtle either, the massive shunt it puts through the transmission can't be doing it any favors. It probably why modded turbo drivers go everywhere like a scolded cat I've tried every combination of internal and external recirc valves with different spring rates and to be honest I've reverted to just the internal forge one as there's minimal difference.

[TFD]

Never had this problem on my Garrett - Nissan cars. Sounds like you guys have a boostcontrole problem. 

The blow-off-valve will not be the problem. When on partial throttle accelerating the bov will be shut. It only opens when vacuum is seen in the intake manifold (so also when cruising, no boost).

You might have a problem with higher boost levels and the way it is controlled by the tiny flapvalve/wastegate in the turbo. Hence why people use an external wastegate. Larger exit so better and more steady boostcontrol. Adding an electronic boostcontroller to an EW will make things even better.

 

My greddy EBC on my GT2871R did very nice things in ways of smoothness.

 

@CraigT: What 2871 housing did you run? Had a .86 on my sr20det and that thing was an on/off switch at 4500 rpm. Not a thing I would want on a VX 

 

[doctorfrag]

Hi Dave, That's a great description, anything up to 10psi is moderateable, but above that the turbo goes into a tipping point and you get full boost. Thorney suggested an HKS boost controller http://www.hks-power.../evc/index.html This would link into the throttle position and adjust boost level to suit. So as far as the oem engine management is concerned you would be running full boost but the level of that full boost would then be determined by the boost controller. Vaux Pop whom sold me the car said he had heard this could be dealt with through mapping, but others have tried with this and failed. At least a boost controller would take the Engine management out of the equation. Joe