club.liberty.asn.au

As part of my mod list for running the pump e85 (viewtopic.php?f=18&t=23635) I have been looking into switching to a 3 port boost controller at the same time but I have had mixed feedback.

I know there are a few people in the ARC running stock factory boost controllers who say it's perfectly adequate but I am also getting the exact opposite opinion and without first hand experience I am not certain what I can expect to achieve given my use and setup.

My car is an every day driver and I don't plan on doing track events with it anytime soon. I would switch to the 3 port controller if it enabled boost to come on at lower RPM and/or allow for greater boost level stability throughout the load/rpm range. I am not necessarily aiming for higher peak boost pressure (stock head and internals after all) but flat torque curve and boot level across a wider rpm range.

Thoughts, suggestions most welcome!

Cheers

Ive heard many times that the factory controller cant bleed the boost off enough to adequately control the boost coming onto boost and then up top.!!

There is a forum member and a mate that has one and i did drive his car for a short period and didnt notice much difference to my stock controller, but our cars differ in mods too so its hard to say what causes what !!

For the sake of $100 i think they are a good investment.!!

I will be going one when my motor is built and when it goes in for a tune checkup after the run in period!

Dan

Thanks Dan. It does seem like a sensible mod, but for some reason not one that is mentioned often. I have never entered a rally event so I cant speak with any experience but I am guessing a large portion of the time is spent at w.o.t. which is nothing like my usage, much like your example of different mods making it hard to make a comparison. Given the negligible cost and the fact that changing injectors and fuel will need a tune anyway i figured if it was going to be beneficial I will add the 3 port controller at the same time. Having said that, I am not someone who mods purely for the sake of it so if there isn't going to be some benefit from it then I will not bother.

Stock boost pressure? Then don't bother.

Running more boost, tuning with a falling boost curve, attempting to boost a fraction earlier, then consider it.

For $100 you'd might as well put it on, simply for the assurance of possibly more stable boost management

GT-B Spec R Pilot wrote:I am aiming for flat torque curve and boost level across a wider rpm range.

I was thinking this too, but this strategy does seem at odds with using any turbo at its peak efficiency, across all rpm and gear ranges.

Indeed I asked this question of one of our most respected tuners, and got this response.

Question:
The aim for my tune is simply driveability & reliability on low max boost 16psi on 98 to suit VF46.

Response:
What is your reason for 16psi?

My rationale:
I'd assume the VF46 is not particularly efficient above 16psi?
After 16psi isn't it just producing more heat?
Lower max boost to allow for occasional spikes due to variances in
fuel quality, air temperature etc.
Lower max boost for more long term reliability.
Happy to admit I'm wrong on all counts

Response:
Turbo can run to 165,000rpm before it goes over the edge, and at this rpm it
can make 18-19psi at low rpm, but at high rpm where engine consumes more air
it will only make 12-13psi, so you end up with a rolling boost curve.

Fuel quality does nothing to change boost levels.
If ecu is setup right, targets will be max boost in taller gears, low gears
don't load the engine enough to make max boost, and with heat sink max boost
is not reached either.
End Quote

I took the advice on board and my tune peaks at 18.5 in third gear which feels just great.
I do recommend an upgrade BOV with the correct spring: my GFB GT Hybrid is just perfect and prevents the higher gear, on the freeway spiking (to around 20psi) I was experiencing on the stock BOV.

On the other hand, Coyote detuned his GT-B on e85 down to 12psi at 180ish atw for a combination of great driveability and reliability.
Its a strategy I'm very interested in, and I'm definitely installing a Prodrive 3 port EBCS regardless.

Cobb one is a fantastic 3 port solenoid as well, new to the market but the coil windings offer fast response. VF46 was 18psi at 2500rpm , good luck getting that out of a stock solenoid

Thanks for the feedback guys, much appreciated. Techworks are fitting a GFB BOV (full plumback) to my car today along with a service. When I am ready to go down the e85 path I will add the 3 port boost controller to the mod list.
What is interesting to me is how much of a difference there is between tuning a turbocharged car engine to a turbocharged main engine on a ship...not just in terms of size & power output but the different factors that need to be considered to achieve an optimal result.
Cheers

GT-B Spec R Pilot wrote:What is interesting to me is how much of a difference there is between tuning a turbocharged car engine to a turbocharged main engine on a ship...not just in terms of size & power output but the different factors that need to be considered to achieve an optimal result.
Cheers

For example being able to stand inside the compressor inlet?

Yes, a lot of the regular cleaning & inspection routines involve climbing inside the engine. The last t/c I overhauled had a 1.2t rotor & the engine had 3 of them, 9 cylinders, 1200mm bore, 2400mm stroke. Flat out was a whopping 78 rpm but it could run stable down to 11 rpm with 6 the absolute minimum although not very stable. I am 6ft tall & I could walk inside the exhaust manifold standing up with a hard hat on & not hit my head. MCR was a bit over 8000bhp/cylinder.