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GTEC's PRV/PBV and all the other Jargon!
#22789
11/01/2006 04:12
11/01/2006 04:12
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Anonymous
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Anonymous
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Hi all, I am new to the whole coop owning / tuning thing so please forgive my stupidity. What is a GTEC 1 / GTEC 2? Where do they come from and where do they fit on the car. What is a PRV or PBV and where do they go? Also i have a decat and want to sort the induction out. Any ideas on how. I was thinking K&N but on some cars there crap and others there great? Any ideas are appreciated 
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Re: GTEC's PRV/PBV and all the other Jargon!
#22790
11/01/2006 04:20
11/01/2006 04:20
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Joined: Dec 2005
Posts: 17,367
Staffordshire
Nigel
Forum veteran
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Forum veteran
Joined: Dec 2005
Posts: 17,367
Staffordshire
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GrahamL writes his own tuning chips - for some reason, they got christened "G-Tec". G-Tec1 is his first attempt, suitable for lightly modded cars. Will give 20 - 30 bhp. G-Tec2 is for more heavily modded cars. Gives another 10bhp or so, but will not work well without supporting mods. EBV / PBV / PRV is the method of controlling boost. This is what i wrote a couple of weeks ago: Quote:
To understand the terms, here's a little lesson on the basic method of boost control - apologies if you know some of this already, but as the forum is trying to rebuild its library of useful threads, I thought it worth repeating.
The standard EBV (Electronic Bleed Valve) senses boost, and when it approaches a predetermined level (about 0.9 - 1.0 bar) an electronic device opens a valve, which sends boost pressure to the wastegate, which opens, allowing exhaust gasses to bypass the turbo, thus reducing the boost. The plus points of this device is that 1) it doesn't start sending boost to the wastegate actuator until it NEEDS to reduce boost, and 2) in the interests of engine longevity, its set fairly low.
A PBV (Passive Bleed Valve) is an adjustable screw valve, which can be preset to constantly bleed some of the boost pressure away from the wastegate actuator, resulting in a higher boost level (or "base boost" if you choose to). The plus point with this type of boost controller is that its a VERY cheap way of ramping up the boost to gain serious performance gains. The negative sides are numerous - 1) Its always bleeding SOME boost away, which is desirable when you need to control boost, but bad when you need all the boost you can get (eg when at higher revs). 2) As well as being a cheap way to increase performance, its a staggeringly simple way of killing your engine. many owners have been tempted to wind out the screw "just a little more", with predictable consequences.
A PRV (Pressure Relief Valve), is an adjustable spring loaded valve, designed to do exactly the same as the EBV, but with the boost level controlled by virtue of adjusting the spring preload screw. As with the EBV, it only bleeds boost to the wastegate actuator when it needs to reduce boost, and so can help the turbo spool up a bit quicker. the warning about overboost is just as valid with this type of controller as with the PBV.
Finally, the many types of electronic boost controllers are essentially PRVs, but with a method of setting and controlling the boost level from an in-car interface.
All non-standard methods of boost control MUST be used in conjunction with a boost gauge, otherwise you're really asking for trouble. Boost gauge is about £30 - £50. Engine is £1000 - to £4000.
![[Linked Image]](https://i.imgur.com/19K9lau.jpg)
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Re: GTEC's PRV/PBV and all the other Jargon!
#22791
11/01/2006 04:31
11/01/2006 04:31
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Anonymous
Unregistered
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Anonymous
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The gtec1 and 2 are up rated chips that you put in your ecu ( with no hp source  ) you can get them from grahaml for about £45 . The prv and pbv control your boost pressure, as far as induction kits go I recommend the ram air kit from torque Italia . I run the gtec1 , prv , ram air induction kit , decat , scorpion zorst 
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Re: GTEC's PRV/PBV and all the other Jargon!
#22792
11/01/2006 04:41
11/01/2006 04:41
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Anonymous
Unregistered
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Anonymous
Unregistered
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Some more explanations.
EBV
The standard Electronic bleed valve is a solenoid air valve that will bleed off the boost pressure to the intake or allow the air to continue the turbo wastegate, depending on whether the valve gets energized or not. Since it has only two possible states, it is pulsed by the ECU control unit in order to continuously control boost level. This methodology exploits the slow mechanical reaction of the solenoid to a position where it is in between ON and OFF, and thus obtaining a continously variable valve from this simple solenoid. There are around 30 pulses/second, and the length of time it is energized during each interval will determine the position and hence amount of air bled away, and ultimately boost level. It doesnt have any sensing capability and neither knows nor cares what boost level is being generated. Boost level is calculated by the ECU from a combination of Air flow sensor and throttle position outputs. This is one of the reasons why it is so poor and maintaining stable boost levels as no direct measurement is made within the boost circuit.
PRV
A pressure relief valve works by preventing any air reaching the wastegate until set opening pressure (boost level) is reached. Once the excess pressure is vented the valve closes again. In theory this type of valve completely eliminates overboost. I said in theory. It can also be used in parallel with the standard EBV to eliminate overboost whilst maintaining the safety features of the ECU control.
PBV
The pressure bleed valve increases boost level by bleeding air away from the wastegate in order to reduce pressure reaching the wastegate. This works in a very similar way to the EBV albeit the setting is fixed and not altered continuously.
Typically PRV's give a much faster turbo spool up and more aggressive boost rise than the PBV. The drawbacks are that the EBV control is bypassed so the ECU cannot reduce boost in the event of a problem. You also have a reduced range of throttle in acheiving full boost so you need to careful in the wet.
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Re: GTEC's PRV/PBV and all the other Jargon!
#22793
11/01/2006 17:34
11/01/2006 17:34
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Anonymous
Unregistered
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Anonymous
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So what exactly does the chip (G-tech 1, 2 etc) do?
How does it work?
What effect does it have on the reliability/life of the engine?
Sorry for the stupid questions, but I have only had experience of chipping a golf to uprate the model (ie rather than paying for higher perf. I just bought the chip VW use anyway).
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Re: GTEC's PRV/PBV and all the other Jargon!
#22795
11/01/2006 22:09
11/01/2006 22:09
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Anonymous
Unregistered
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Anonymous
Unregistered
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Gtecs give you more boost and also increased fuelling which ensures your cars not running lean.
My Gtec1 removed the 'limiter' in 1st and 2nd and it increased boost from 1.0Bar to 1.2Bar in all the other gears. (1st and 2nd Boost to 1.2Bar as well which can be tricky in the wet).
Not sure of offical bhp increases but in the region of +20 Bhp.
All that said, it's advisable to have it on a rolling road to check the fuelling afterwards.
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Re: GTEC's PRV/PBV and all the other Jargon!
#22796
11/01/2006 22:13
11/01/2006 22:13
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Anonymous
Unregistered
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Anonymous
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Sure someone will correct me but basically both chips modify the fuel/ignition/boost maps - i.e little bit more fuel, more ignition advance and higher boost.
In terms of boost there is also a boost limit on the coupe in 1st/2nd gear. The GTECHs remove this limit.
Although both chips can be fitted in a car that still uses the fiat EBV, its recommended that they be fitted with a different boost controller (PRV/PBV/Electronic controllers) and also a boost gauge.
The GTECH will also increase the fueling, something which can have a massive affect with other modications.
As with all modifications there will be a differing affect on components. Done correctly within the tolerances of certain parts the performance can be increased and have no detremental affect on wear. Similarly you could upgrade many components to make the car easier to drive, smoother and potentially produce the same power as before easier/at lower boost.
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Re: GTEC's PRV/PBV and all the other Jargon!
#22798
11/01/2006 22:20
11/01/2006 22:20
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Anonymous
Unregistered
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Anonymous
Unregistered
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Hi Phil - Sadly I'm no expert, but previous setups i've seen have been a combination of PRV and Gtec1.
I just assumed that this was than the safest method as i'm not entirely sure how well the standard chip fuels the car when running higher boost.
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Re: GTEC's PRV/PBV and all the other Jargon!
#22799
11/01/2006 22:22
11/01/2006 22:22
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Anonymous
Unregistered
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Anonymous
Unregistered
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Yes. Upping the boost with a PRV, the Gtech1 will control the timing and fuelling (only) making it safer than the original.
(still wise to RR it tho)
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Re: GTEC's PRV/PBV and all the other Jargon!
#22800
11/01/2006 22:26
11/01/2006 22:26
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Anonymous
Unregistered
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Anonymous
Unregistered
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To make the Gtec-1 absolutely safe, along with any other mods you are considering, consider a Unichip too (mapped ontop of the Gtec-1) which is mapped on a rolling road to your specific car to ensure spot on fuelling. There's a group buy thread going on now which is very much worth considering...
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Re: GTEC's PRV/PBV and all the other Jargon!
#22801
11/01/2006 23:11
11/01/2006 23:11
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Anonymous
Unregistered
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Anonymous
Unregistered
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As far as I'm aware, (although I'm sure GrahamL will be along soon to correct me if wrong) if you were to replace the standard chip with a GTEC 1 and still using the standard Fiat EBV, (see above posts for description EBV), then you would get approx 1.2bar boost in all gears with upto 1.4bar overboost. I also believe the GTEC1 does not adjust the ignition, it only changes the boost level on the standard EBV and has different fuel maps. Should be good for approx 30bhp. However on a standard coupe 1.2 bar will shorten the std turbo life quickly, and the standard intercooler will also struggle to cope. (In saying that I think quite a few coupe's on the forum have been running fine with this set up). You should get an engine health check done by one of the Fiat specialists, (Powerfiat, TorqueItalia, Motomech) however before fitting the chip and should also think of getting it rolling roaded to check the fueling is still ok with your particular car. GTEC2 chip I belive has similar levels of boost if you were to use the standard fiat EBV but also runs extra ignition advance and therefore gives more power, (maybe 40bhp+). However the extra ignition it gives means you will need aditional cooling to keep the combustion temperatures down, ie Front Mounted Intercooler / water injection etc. If you fit you own PRV/PBV/EBV then you will be able to set the boost level you want (usually somewhere between 1.0 - 1.4bar depending on which turbo you have and what intercooler/water injection). The Gtecs will then just set the fueling maps the car uses, (+ignition advance in the case of the Gtec2). The ideal route if you are looking for more power but safely is the Unichip/custom mapped chip. This will set the optimum fueling and boost levels that your particular coupe can safely habdle. Chris
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Re: GTEC's PRV/PBV and all the other Jargon!
#22802
11/01/2006 23:15
11/01/2006 23:15
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Anonymous
Unregistered
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Anonymous
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Quote:
However on a standard coupe 1.2 bar will shorten the std turbo life quickly
In the handbook it says the (std) turbo is rated to 1.20bar max.
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Re: GTEC's PRV/PBV and all the other Jargon!
#22803
11/01/2006 23:16
11/01/2006 23:16
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Joined: Dec 2005
Posts: 21,071
Chertsey in the Thames
bockers
Hon Club Member 007
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Hon Club Member 007
Forum Fossil
Joined: Dec 2005
Posts: 21,071
Chertsey in the Thames
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Re Boost limit in 1st and 2nd. I learnt form a post on the old forum that the Coupe ECU does not actually limit boost by gear, the ecu does not know what gear you are in IIRC. What is does do is limit the engine acceleration. This means that when the engine in accelerating too fast due to wheelspin (as is more likely in 1st and 2nd) then it will limit the max boost. So a steady acceleration on dry road with good tyres should see max boost in these gears too. May be of interest to someone JOhn
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Re: GTEC's PRV/PBV and all the other Jargon!
#22804
11/01/2006 23:31
11/01/2006 23:31
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Quote:
However on a standard coupe 1.2 bar will shorten the std turbo life quickly
In the handbook it says the (std) turbo is rated to 1.20bar max.
Thats max, (also for overboost), not to be run at 1.2bar all the time  . It was designed to run at around 1.0bar. With its 270bearing the turbo will wear quickly at 1.2bar and produce more heat.
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Re: GTEC's PRV/PBV and all the other Jargon!
#22805
11/01/2006 23:43
11/01/2006 23:43
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Anonymous
Unregistered
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Anonymous
Unregistered
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that's all right then, got my PBV set to 1.2 max which reduces to something like 1.0 - 0.9 as the revs climb Must say that the Gtec1 chip together with cosmograph's PBV feels a mighty improvement in the midrange compared to standard. A very worthwhile total investment of, what, under £70, plus £45 to get the fuelling checked on the Rolling Road on Saturday
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Re: GTEC's PRV/PBV and all the other Jargon!
#22806
12/01/2006 00:04
12/01/2006 00:04
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Anonymous
Unregistered
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Anonymous
Unregistered
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Quote:
Re Boost limit in 1st and 2nd.
I learnt form a post on the old forum that the Coupe ECU does not actually limit boost by gear, the ecu does not know what gear you are in IIRC. What is does do is limit the engine acceleration. This means that when the engine in accelerating too fast due to wheelspin (as is more likely in 1st and 2nd) then it will limit the max boost. So a steady acceleration on dry road with good tyres should see max boost in these gears too.
May be of interest to someone
JOhn
Thats my understanding too John. There is no actual boost limiter but a limit on how quickly the revs are allowed to rise. If they rise too quickly i.e (1st/ 2nd gear) boost level is reduced.
Not only does the ECU not know what gear you are in it doesnt know your boost level either. Both parameters are inferred from one or more of load, revs, road speed, throttle position and MAF inputs.
Last edited by cosmograph; 12/01/2006 00:05.
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