Can someone post any link to the Gtech site? I just can't find any info regarding this chip other than the forum! <img src="/forum/images/graemlins/grin.gif" alt="" />
Also - and sorry : I'm new, don't blame me <img src="/forum/images/graemlins/tongue.gif" alt="" /> - what does PRV stands for <img src="/forum/images/graemlins/confused.gif" alt="" />

Does anyone have some link to the Gtech site? I just can't find any info regarding it other than the forum <img src="/forum/images/graemlins/confused.gif" alt="" />
And - I'm new, don't blame me <img src="/forum/images/graemlins/smile.gif" alt="" /> - what does PRV stands for?
Thanks

nelson,

you can PM GrahamL for the chip.

PRV : Passive Relief Valve

aka

PRV : Pressure Relief Valve.

cheers.

Like those dump valves from baieys?

Sorry again, but PM stands for???

Thanks for the shared info :-)

PM : private message (click on GrahamL's name).

DumpValve is different.

ok!!

Thanks once again :-)

Nelson, PRV : Pressure Relief Valves are used to control the boost, you should buy this along with the Gtech chip to increase your boost.

cheers

You don't actually need to have a PRV (or a boost gauge) to run a GTEC chip - it can be used with the standard EBV (electronic bleed valve) if desired. Many people use a PRV (which does need a boost gauge!) with aftermarket engine management chips to help control overboost.

I use a GTech 1 (1.2 bar) chip with the standard EBV and no problems. If you don't get overboost with the standard setup you should be fine. A boost gauge is always a good idea though. <img src="/forum/images/graemlins/smile.gif" alt="" />

So a PRV it's a diferent thing than a dump valve I assume from your posts!
Can you enlight me about what does what?
Do you consider that's best achieving both?
regards

Welcome to the forum Nelson - I was in exactly the same boat when I bought the Coop in August, so don't worry about it.

They are two very different things - here's what they do :

1. Dump valve : imagine the turbo is spinning and delivering boost, via the throttle, back into the engine. When you change gear, brake, or otherwise come off the throttle, you will close the throttle, effectively closing a door in this induction path.

All this compressed air would, in theory, have nowhere to go, and it would stop the turbo spinning very abruptly. This is extremely bad for both turbo lag (the turbo would stop and need to restart from zero) and for the turbo bearings (all of a sudden they'd go from 100k rpm to 0 rpm).

A dump valve provides an outlet for this compressed air, so as one path closes (i.e the route back into the throttle body) this path opens - the excess air is vented, the turbo keeps spinning and it makes for a much more smooth transition from on/off boost, whilst cutting lag and saving the turbo from stopping dead.

The fact that it also makes an excellent "PSSSSS-TSSSSSSSSSSSSH" noise with an atmospheric dump valve is neither here or there, of course <img src="/forum/images/graemlins/wink.gif" alt="" />

At least that's how I think of it <img src="/forum/images/graemlins/wink.gif" alt="" />

Seriously though, the only real reason to change the standard dump valve is that it is a fairly cheap, plastic item that can be prone to leak boost, which of course is not ideal. A boost gauge will let you know, unless you can actually hearing it mooing <img src="/forum/images/graemlins/wink.gif" alt="" /> You won't get any performance gain from an uprated DV if the standard one is working fine.

Click for fitting guide.

2. EBVs / PRVs / PBVs :

Click

And Click for a fitting guide

<img src="/forum/images/graemlins/smile.gif" alt="" />

Great post Jayell!
Thanks for the info and the links <img src="/forum/images/graemlins/wink.gif" alt="" />

Thanks Nelson. My last bit of advice is, only 6 months ago I was asking about a GTEC 1 chip, a PRV and maybe a dump valve. It's now 6 months and about 2.5k later............

Modifying really fccuks you up <img src="/forum/images/graemlins/laugh.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" />

wakakaa

<img src="/forum/images/graemlins/smile.gif" alt="" />

Yes, I know! <img src="/forum/images/graemlins/crazy.gif" alt="" />

It's so so bad to the wallet... but puts a so so big smile on your face <img src="/forum/images/graemlins/laugh.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" /> <img src="/forum/images/graemlins/laugh.gif" alt="" />

Nice post mate, and thanks for your PMs!!

i was running STD for more than 5 years and i have started with the Damp Valve (Dv26),,,, it has a perfect sound and i lov my car more and more each time I put it on road!

Now i have got the PRV & Gtech1 chip (thanks to graham & Robin!) and i need to install them. i know it is an easy job as the Damp Valve, but, can i fit the PRV first and rise the boost to 1.2 bar without installing the chip?? Can my fuel pump be capable to provide the required fuel to sustain this increase in boost without using the chip?? <img src="/forum/images/graemlins/confused.gif" alt="" />

Cheers <img src="/forum/images/graemlins/smile.gif" alt="" />

dont think so mate, as far as i know the chip is needed to tell the pump to pump more fuel, you could increase the boost but the fuelling will stay the same.... not good

Just install the chip mate, it's the chip that enables you to use the PRV to increase the boost. It's a really easy job and when I say easy, I mean I was able to do it without fccuking it up <img src="/forum/images/graemlins/laugh.gif" alt="" /> 30 mins tops, doddle.

The chip alters the fueling and ignition needed to run at 1.2bar

Aye exactly Dan <img src="/forum/images/graemlins/smile.gif" alt="" />

just a quick question , can the standard T28 turbo unit
run a sustained 1.2 Bar of boost ?

.

nope - it will tail off to 0.9 or 0.8 bar at 6000 rpm.

Not recommended running even roller bearing turbos at this level at redline, that's right isn't it suba ? Charge temps and all that malarkey

as long as you have the right turbo to hold the boost with a boost controller + the right cooling + the right fuelling then you can run 1.2 bar at the redline....

With the standard intercooler and turbo 1.2 bar tailing off to 0.8 is about the upper limit before the charge temps get too high in 4th / 5th gear. with the same boost profile accross the rev range you'll get less heat generated from a roller bearing turbo, and so you demand for cooling will be less as well....however roller bearings + hybrids usually hold more boost so on the standard IC the general rule is not to boost them over 1.0 or 1.1 bar until the cooling is upgraded.

What do you mean!! <img src="/forum/images/graemlins/confused.gif" alt="" />
so why we are using PRVs, if the STD turbo cant be used for 1.2 bar!!??

cheers

http://photobucket.com/albums/a198/suba11/?action=view&current=coopdyno209.jpg

See link for the typical boost profile for a standard turbo and standard actuator at 1.2 bar. You get 1.2 bar peak and midrange, but the wastegate can't keep that pressure as the revs increase - so the boost tails off as the revs rise, though as the revs rise you get more N/A power anyway which compensates for this. The peak power is generated more or less at 6000 revs - so this figure is largely depenant on the boost level at this point.

hence why cars with better turbos have a stronger top end.

ok, i got your point, but we will still get the 1.2 bar. i mean that we can rise the boost of the STD turbo up to 1.2 bar (but it will hold it only for 6000rpm as you have mentiond) ryt??

yes - pretty much.

when people talk about 1.2 bar this is generally the sustained max boost level at about 3500 rpm with the car under load and throttle wide open. You can run more overboost depending on your set up. the car wont hold 1.2 bar and then suddenly drop off to 0.8 on a standard turbo - it will drop off progressively - see the link to my old power / boost graphs for an example of how/when the boost drops off on the standard turbo throughout the rev range.

cheers Suba, <img src="/forum/images/graemlins/wink.gif" alt="" />

Another helpful post suba, cheers. Favour please - check out my sig (assuming everything has been installed, which it will be soon) and tell me what boost level you would run, both and @ redline <img src="/forum/images/graemlins/smile.gif" alt="" />