Author Topic: Boost return removal  (Read 4032 times)

Offline XRrich

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Boost return removal
« on: March 02, 2010, 06:24:50 pm »

Hi i have heard about this, and have the guide, just wondering whether to do it or not.

Is it worth it?
What is gained?

Pros and cons

Any info on this would be appriciated

Thanks
Rich

Offline Puncharado

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Re: Boost return removal
« Reply #1 on: March 02, 2010, 06:47:57 pm »
This has been covered loads of times. Run a search from the forum home page, plenty of posts.

Offline XRrich

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Re: Boost return removal
« Reply #2 on: March 02, 2010, 07:01:12 pm »
Sorry.
I have had a search and only found guides on how to do it.
Cant seem to fine anything on ,power gain, pros and cons

Thanks
Rich

Offline Puncharado

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Re: Boost return removal
« Reply #3 on: March 02, 2010, 07:56:57 pm »
Sorry.
I have had a search and only found guides on how to do it.
Cant seem to fine anything on ,power gain, pros and cons

Thanks
Rich

No worries!

Pros: -oil and fuel vapour don't enter the intake air and alter the mixture. Only colder, denser air is drawn into the charger. Personally I'm not convinced this is much of an issue as the return air has already been through the intercooler, and although still warmer than fresh air I can't see it getting any hotter during it's fleeting pass of the engine. Plus all the intake air gets heated through compression by the charger anyway.
Cons: - No oil mist to lube the charger hence the need to periodically spray PTFE into the charger. Polar bears and penguins will die due to the increase in global warming because of the extra pollution you've created from the oil and fuel vapour on top of your exhaust emissions.
Adding a catch tank could be considered a pro or a con, depends on you.

Offline XRrich

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Re: Boost return removal
« Reply #4 on: March 02, 2010, 10:46:24 pm »
cheers buddy
Do you gain power from it?

Might give it a go and see how it goes.

Offline Justin14100

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Re: Boost return removal
« Reply #5 on: March 02, 2010, 11:31:55 pm »
cheers buddy
Do you gain power from it?

Might give it a go and see how it goes.

power gain is very small. prehaps not worth the money of the catch tank. I'm not sold on this mod. some say it makes your charger last longer ect.

spend the time / money on something else that adds power IMO. makes it louder too, which is shit for motorway runs!

Offline XRrich

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Re: Boost return removal
« Reply #6 on: March 03, 2010, 08:10:47 am »
Its no cost to me as im fabricating my own catch tank. luckily im doing welding and fabrication at college ;)
So yeah im not sure if im keen on it.

Offline Justin14100

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Re: Boost return removal
« Reply #7 on: March 03, 2010, 09:55:17 am »
some say it makes your charger last longer ect.

hummm.... i'd say it doesnt last as long, as with the PTFE spray people (from what i've seen) tend to spray too much in....

and if i can find a picture of the charger i rebuilt which had a boost return mod, you wouldnt like the look of the inside of the charger!



i just dont rate the mod, as ive said before. im sure vw knew what they were doing

Offline hayesey

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Re: Boost return removal
« Reply #8 on: March 03, 2010, 10:26:04 am »
yeah VW were making it run as quiet as possible and using the only lubrication method possible for them, they couldn;'t expect the orioginal buyers of new g40s in the early 90s to spray the right amount of ptfe lube in every 1000 miles or so could they?  They also needed a way of silencing the boost return as again, a lot og people paying £11k in 1991 for a polo wouldn;'t be too happy it if was dead noisey.

Personally, I think it is to keep the charger in better order which is the best advantage of this.  The proper PTFE lube applied in correct quantities (i.e. 2 or 3 short, half second sprays every 1000 miles) will keep it in much better condition than the horrible watery shite that comes out of the oil breather, ever emptied a catch tank out? 


Then the other benefit is that the charger is only sucking in cold, fresh air instead of warm air re-circulating.  Colder intake air is always good for power as it contains more oxygen per unit of volume and that allows you to burn more fuel.  The difference in temp between air coming back through the boost return and fresh air will be significant, esp in the UK where it's fecking freezing half the time!

You can damage the charger by pouring miles too much PTFE into it but you can also damage the charger by pouring pennies into it, just don't do that and you'll be fine.

Offline Jezza-7

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Re: Boost return removal
« Reply #9 on: March 03, 2010, 05:13:36 pm »
I agree with hayesey with this. I have never known anyone to have problems with this mod.

I think it alos tidy's up the engine a bit too.

Rich how are you desinging your tank? I have just made one and its a good fit so if you want measurements let me know. You want pics of tank?

Offline XRrich

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Re: Boost return removal
« Reply #10 on: March 03, 2010, 05:25:40 pm »
I was just desinngin it now. i wasnt sure whether to make a "groovey" one or just standerd.. was just looking at ideas.
Yeah send some pics and emasurments that would be greatt  ;D

Offline Puncharado

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Re: Boost return removal
« Reply #11 on: March 03, 2010, 05:45:35 pm »
I'm on the fence with it too. Personally, I like the look of the pipework in the engine bay. I don't want the shitty crankcase oil in the charger (or collecting in the intercooler ;)), but as I'm not entirely sold on the hot air opinion I'm thinking of a halfway house. My plan is to junk the diaphragm valve, one way valve, and carbon canister, and fit a catch tank but keep the re-circ air. But when the car is finally back up and running I'll thermocouple it up and try both ways and see if there is a difference. Then I'll know for sure and can make a final decision.

Offline XRrich

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Re: Boost return removal
« Reply #12 on: March 03, 2010, 06:16:59 pm »
Too much PTFE?

Offline Puncharado

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Re: Boost return removal
« Reply #13 on: March 03, 2010, 06:30:00 pm »
Looks like far more than a couple of short squirts every 1k! But charger could have done 100k, any idea of the mileage since the previous rebuild Rae?

Offline Jezza-7

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Re: Boost return removal
« Reply #14 on: March 03, 2010, 06:34:13 pm »
Ok, this is where i mounted it so i didnt have to drill holes in the engine bulkheads.








Only got 1 bolt holding it in place but its not excatly gonna be heavy and move much.

Got the design from a good mate on here antony.

Was made from 2 pieces of ally, both cut into a "c" shape with about 2 inches longer on piece for mounting.

Has a baffle inside that was tac welded. All the fittings were done on a lathe. I had mine welded on the outside where as my mate had his welded from the inside. It looks neater having welds on the inside but i kinda messed up.

Here is a rough diagram, its not the best but has taken me a while to do.

The dotted line in the 1st diagram is a bend on the 1st piece of ally for attachment.



Hope this is ok.

Measurements are

120mm across

150mm long

90mm depth
           
« Last Edit: March 03, 2010, 06:36:38 pm by Jezza-7 »