Carrera GT

http://cgi.aol.ebay.com/ebaymotors/w...oDisplayType=2

This listing on eBay caught my eye.

Has anyone had experience with this Greddy boost controller?

viperbob

The only experience I have with the Protec is watching it sit on the floor of my garage. The one shown might be an old model. The one I have has a small LCD screen. This is why I have not installed it yet as I can not find a spot to mount it.

This was recommended by Todd at Protomotive to go along with the other work that I have done to my car. Can't give any more info than that right now.

KRA993tt

I drove a 96TT that had that unit installed when I was shopping for a 993TT and it seemed like a fairly simple and cockpit adjustable instrument. The only problem I had was that was the only modification done to the engine no aux oil cooler nothing. It just seemed like they tacked it on to bump up the boost. Bottom line the idea of being able to make adjustments from the cockpit sounded like a good idea and it definitely bumped up the boost.

ScottMellor

I too would be concerned about a car that has had the boost turned up as it's only mod.
Big intercoolers and oil coolers are a "must have" for a 993TT to make big power for any length of time. I would be terrified of an Autothority modded car making 1.3 bar of boost and 570 hp without any other longevity mods.
Sounds like a hand grenade.

Jeff 993TT

The previous owner had installed one on my car. It wasn't installed/set correctly, so I am hoping that it didn't do any damage. I removed it promptly.

My recommendation would be to avoid it. Dialing up the boost ( without the ECU knowing about it ) can be a dangerous thing. You're just asking for detonation.

And I'll also echo the other's comments about the other sub systems ( intercooler, oil cooler, fuel pressure regulator, fuel injetors, etc ) need to be upgraded as part of a whole package. Doing just one thing is a bit risky, imho.

Garrick Louie

I agree with many of the things that Jeff has said. The pursuit of extra power almost always has an effect on engine life - nothing is free.

However, the ecu still is aware of the amount of boost since it is getting this information from the MAF and extrapolating the airflow into boost based on a set of maps. The ecu no longer has direct control over the boost whereas before it could alter the boost control frequency valve directly. The ecu is never able to directly 'control' or meter exact amounts of boost since boost is dependent under so many more factors then wastegate control.

Normally if the ecu detects knock it will pull timing, reduce boost, and cut fuel if all else fails in order to save the motor. Unless you have bad gas and really poor running conditions the ecu will never have to reduce boost. By installing a boost controller you take away the car's ability to control the wastegates but the car may still cut fuel and/or pull timing which in turn will reduce boost.

Now if you really want a functional boost controller you also have to eliminate the ecu's fuel cut ability...on factory ecus the fuel cut occurs at about .9bar. If you try to raise boost past .9bar the ecu will sense an overboost situation and it will limit boost by altering the signal to the frequency valve (it will open the valve) to force the wastegates open. Since you have bypassed this valve the boost will not cut and then the ecu will cut fuel which will esssentially limit your boost to .9bar

So a properly installed boost controller will only work properly if it is set to boost below the fuel cut or if you bypass fuel cut which will limit the ecu's ability to save the motor should something go wrong.

I believe the Unichip system is able to raise beyond the factory boost limit because it uses a fuel cut interceptor as part of it's piggyback computer system. To get 20% more boost it must 'fool' the ecu into thinking it is getting 20% less airflow from the MAF signal and this causes the car to run lean which is why really tuned systems add yet another box like an AFC to piggyback additional injectors. A proper interceptor should not change the signal until it reaches the signal threshold where boost cut occurs.

TB993tt

Garrick Louie
Excellent appraisal on the workings of the ECU and the effect of this type of boost controller. I ran one on my tt a few years ago (before current motor) and whilst the boost went up, as you say, the ECU cut the fuel when it decided there was too much air mass and its signal to the turbos wastegate wasn't having the desired effect - it feels like a stuttering similar to a stock 993tt rev limiter.

Michael-Dallas

It's actually called Profec (don't think GReddy makes a "Protec"). If it's a Profec B, then it is a fairly simple, reliable, and good boost controller (at least in Japanese turbo cars). IIRC, there are 3 *****, one to control gain and 2 to control boost (one for low boost and another for high boost). The only catch is that you need a boost gauge to properly set boost.

Another good boost controller I would recommend would be the Blitz SBC-id or SBC-DC. These two have built-in boost gauges (so you don't necessarily need to buy an aftermarket one or rely on the factory one if it's inaccurate). The display and control unit is separate (unlike many other boost controllers) so you can mount the display virtually anywhere (it's 1/2 DIN and somewhat thin).

Keep in mind that I recommend these out of my experience w/ them in Japanese cars.

Michael.

Garrick Louie

TB993tt,

You pretty much have it down when you describe the behavior of boost controllers in our cars if we try to boost past .9bar on the stock ecu.

To effectively raise boost beyond .9bar with a controller we either need modified ecu or a piggyback ecu.

To my knowledge Unichip and other piggyback ecus are in our cars is problematic b/c we need to trust that the motor will have enough fuel. To avoid fuel cut we tell the ecu we only have about 40lbs of air per minute but in reality we are pushing 50-60lbs then we will have a lean condition even with a rising rate fuel pressure regulator.

So it might be 'okay' to fool the ecu if you are running the small stock turbos which are not really capable of flowing enough air to break anything but for more serious mods I am not sure how you can get by without extra injectors or a modified ecu. I think the modified ecu route would be the most ideal and simple.

Carrera GT

Thanks for the comments. Yes, it's "Profec" and Greddy shows some newer units on their site, but nothing specific to the 993TT.

The subtext to my question has come out in this thread: unless the ECU manages all the usual controls and parameters (air/fuel, throttle, boost, 02) it's practically impossible to take the engine beyond normal settings without some, let's say, "less than sophisticated" tweaks.

Aside from one positive note on Protomotive, I don't see the sort of "plug and play" solution I'd expect to find for the 993 Turbo.

Maybe Andial?

Is there a Ruf option?

Garrick Louie

Well on any turbo car you pretty much have to defeat fuel cut to turn up the boost with a boost controller. This is not unique to 993s.

You can install the boost controller without any doing anything else but you will be limited to setting boost somewhere below right below.9bar.

If someone had a stock turbo they could defeat the factory fuel cut and run a controller on the dyno and check the A/Fs to see if the motor is getting enough fuel...most factory turbo cars running stock turbos will have enough fuel but I do not know for sure on the 993s.