Fiat 124 Spider Forum banner

1 - 20 of 319 Posts

·
Vendor
Joined
·
3,124 Posts
Discussion Starter #1 (Edited)
I am getting a lot of questions from forum members about the GFB DV+

It's a good product, but I think it's a bit misunderstood. Let's take a look at it.



The GFB DV+ is a direct replacement part for the stock diverted valve. It differs only slightly in design from the stock part, but significantly in quality of components.

So what is a Diverter Valve? In the old days it was called a bypass valve, or a blow off valve, but it's a little more sophisticated. The diverter valve is an ECU controlled valve that relives air pressure in the intercooler and associated piping by opening up under specific conditions and venting that air back into the turbo's intake port. It does this in two situations. First it opens up when the car is on boost and the driver closes the throttle. Second it happens of the ECU feels it needs to open the valve to protect the engine. For example it would do this if the boost line came off of the wastegate actuator, or some other malfunction caused an overboost. (I'm simplifying here)

The factory diverter valve works pretty well. It responds fast enough to offer the protection it should, and when it's closed it doesn't leak too badly. However it does leak, meaning that the turbo has to work a little harder than it otherwise would to create air pressure that's wasted.This leaking causes a very small delay in the time it takes the turbo to spin up, and costs a very small amount of power when on boost.

The GFB valve when closed leaks less than the stock valve. Thus the turbo can spin up a little faster and at least in theory power on boost will be a little higher. However as compared with a stock valve that's in good condition and operating properly, the differences are very slight, so slight that only people really in tune with their car will have a chance of noticing.

Now, IF the stock valve, which is pretty low quality, isn't perfectly healthy, you will notice a difference when swapping in the GFB part. When you hear about someone putting in a GFB and raving about the improvement, it's usually because there was something wrong with the stock valve. The GFB valves seem to last forever so they give very consistent reliable performance.

In the 500 Abarth world the GFB valves are very popular. They are also very popular on a lot of other European turbo cars. It's a good product, just don't expect a big change in power as compared with a properly working stock valve.

We have them at EC, they are here: https://shopeurocompulsion.net/collections/fiat-124/products/go-fast-bits-dv

Greg
 

·
Registered
Joined
·
23 Posts
Hey Greg - question.

How difficult is the install? Been debating whether I should get this now, or wait until I get more familiar with the car. Would you recommend a first-timer doing the install themselves?
 

·
Registered
Joined
·
189 Posts
Hey Greg - question.

How difficult is the install? Been debating whether I should get this now, or wait until I get more familiar with the car. Would you recommend a first-timer doing the install themselves?
I am at home with dynamos, point and SU carbs ( ask your Dad ).
These new engines need a laptop more than my tool kit - but I have just fitted the GFB DV+ 15 mins from start to finish. It as easy as it gets on modern engines. My expectations were exactly as Greg indicated - Not an increase in power but a more consistent response especially at low revs. It works for me.
Danny
 

·
Vendor
Joined
·
3,124 Posts
Discussion Starter #6
I am at home with dynamos, point and SU carbs ( ask your Dad ).
I'm old enough to know what all that stuff is, although we never had SU carbs on Fiats or Alfas, that was a British car thing.

These new engines need a laptop more than my tool kit - but I have just fitted the GFB DV+ 15 mins from start to finish. It as easy as it gets on modern engines. My expectations were exactly as Greg indicated - Not an increase in power but a more consistent response especially at low revs. It works for me.
Danny
I'm glad you like it. You used the term "more consistent" that's a very good way to put it. As the stock valve opens and closes it doesn't always close consistently, the GFB is much more consistent. I forgot to point that out.

Greg
 

·
Registered
Joined
·
958 Posts
I'm old enough to know what all that stuff is, although we never had SU carbs on Fiats or Alfas, that was a British car thing.



I'm glad you like it. You used the term "more consistent" that's a very good way to put it. As the stock valve opens and closes it doesn't always close consistently, the GFB is much more consistent. I forgot to point that out.

Greg
I added the GFB to my Lusso and find that boost seems to come on a little earlier and smoother. Does that make sense?

The only difficulty in the installation was that I had to remover the V1 intake tube because it is thicker than stock and made the GFB a tight fit. Once the GFB was on, the V1 intake tube went back on with only a little coaxing into the narrowed gap between the GFB and the turbo.
 
  • Like
Reactions: NYProf

·
Vendor
Joined
·
3,124 Posts
Discussion Starter #8
I added the GFB to my Lusso and find that boost seems to come on a little earlier and smoother. Does that make sense?
That does make sense. It's not so much that it's giving you more power, but it gives it too you a little sooner, and smoother.

The only difficulty in the installation was that I had to remover the V1 intake tube because it is thicker than stock and made the GFB a tight fit. Once the GFB was on, the V1 intake tube went back on with only a little coaxing into the narrowed gap between the GFB and the turbo.
That is true, The GFB valve is bigger than the stock valve. Our intakes are made from thicker materiel than the stock intakes, so when you combine them, there isn't much room left. They do fit together though. I suggest putting the clamp on first, then sliding the intake onto the turbo inlet and into the clamp. Coating the intake area near the clamp with dish soap and water makes it really slippery and it goes on easily.

Greg
 

·
Registered
Joined
·
76 Posts
I just got the GFB DV+ today and it took maybe 10 minutes to install. I did not even have to change out of work duds. You will need a 5mm hex driver and maybe an extension to get at that bottom screw. While I cannot claim any power gains, it does seem to have smoothed the power under boost out. I'm surprised as how ill fit the factory valve was. There was a lot of slop in the factory piston. Overall, I'm happy with the money spent and may do the same mod to my wife's N55 engine in her car. It looks like the same valve would fit that too.
 

·
Registered
Joined
·
249 Posts
@Greg: I'm thinking about ordering the GFB DV+. The order page has an option for 'Extended Bolts'. Do I need extended or standard bolts for a 124?

Thx, S
 

·
Registered
Joined
·
351 Posts
@Greg : I'm thinking about ordering the GFB DV+. The order page has an option for 'Extended Bolts'. Do I need extended or standard bolts for a 124?

Thx, S
Having installed one, I can tell you that you need the extended bolts. The housing for the DV+ is thicker than the stock, so the original bolts won't reach.
 

·
Registered
Joined
·
269 Posts
Having installed one, I can tell you that you need the extended bolts. The housing for the DV+ is thicker than the stock, so the original bolts won't reach.
don't recall that option about the extended bolts when I ordered mine, and haven't installed yet. Will I need these longer bolts? Don't want to start pulling things apart and find out I can't install.

tia,

Mark
 

·
Registered
Joined
·
351 Posts
don't recall that option about the extended bolts when I ordered mine, and haven't installed yet. Will I need these longer bolts? Don't want to start pulling things apart and find out I can't install.

tia,

Mark
The longer bolts came with it and weren't an option, so I don't know. Got mine from Eurocompulsion, for what it's worth. The last instruction was "be sure to use the supplied longer bolts to reinstall the valve."
 

·
Registered
Joined
·
269 Posts
The longer bolts came with it and weren't an option, so I don't know. Got mine from Eurocompulsion, for what it's worth. The last instruction was "be sure to use the supplied longer bolts to reinstall the valve."
purchased from Eurocompulsion and option wasn't there, but is now. I'll just measure the spacing adding in the gfb depth to be sure supplied bolts will reach.
 

·
Registered
Joined
·
351 Posts
purchased from Eurocompulsion and option wasn't there, but is now. I'll just measure the spacing adding in the gfb depth to be sure supplied bolts will reach.
Or just stick the bolts through the new valve housing and see how much thread extends beyond it.

Maybe they've changed the housing so it's not as thick and longer bolts aren't needed? Beats me. We need Greg's insight.
 

·
Vendor
Joined
·
3,124 Posts
Discussion Starter #17
@Greg: I'm thinking about ordering the GFB DV+. The order page has an option for 'Extended Bolts'. Do I need extended or standard bolts for a 124?

Thx, S

Use the standard bolts. The extended bolts are used when the DV+ is combined with a Forge blow off plate.

Greg
 

·
Registered
Joined
·
351 Posts
Use the standard bolts. The extended bolts are used when the DV+ is combined with a Forge blow off plate.

Greg
Now I'm curious as to what's changed. I didn't order a Forge blow off plate, just the DV+ valve. The plastic housing of the valve was significantly thicker than the stock housing and the longer bolts were needed.

The one pictured in the OP is about the size of the stock valve, and I was surprised how much larger the one I got was.

Not that any of this actually matters, of course. Just curious.
 

·
Registered
Joined
·
269 Posts
Use the standard bolts. The extended bolts are used when the DV+ is combined with a Forge blow off plate.

Greg
I see...so the bolts you originally provided allow for the added depth of the dv+ but nothing else. If something else is stacked on top as well, the longer bolts are then needed. Guess this will still be my weekend project :)

Thanks for clarifying,

Mark
 

·
Vendor
Joined
·
3,124 Posts
Discussion Starter #20
I see...so the bolts you originally provided allow for the added depth of the dv+ but nothing else. If something else is stacked on top as well, the longer bolts are then needed. Guess this will still be my weekend project :)

Thanks for clarifying,

Mark
That's exactly right. The DV+ comes with it's own bolts. However if you are ALSO adding in a plate to change it into a blow off valve, meaning it will vent to the atmosphere and make a "whoosh" sound, you will need the longer bolts.

Greg
 
1 - 20 of 319 Posts
Top