Bleed Valve

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Discussion

M3EVO

Original Poster:

1,564 posts

256 months

Tuesday 4th March 2003
quotequote all
Many moons ago, I owned a Series 1 Escort RS Turbo. It was a standard car apart from a S/S exhaust. To acheive a performance gain I used the bleed valve concept to confuse the ECU into thinking that more boost was required by fitting a valve in the signal line from the inlet manifold to the amal valve (think that is correct). This would then hold the wastegate actuator so more boost was acheived.

My question is - Can this method of tuning a turbocharged car be used on more modern cars such as the VAG range of 1.8T's???

deltaf

1,384 posts

256 months

Tuesday 4th March 2003
quotequote all
Yes. There can be problems if you overdo it though.
Also, there may be an boost cut defence built in to the ecu.
The only way to be sure, would be to try it.
Another way of acheiving the same thing would be to shim the actuator spring, or buy an uprated and adjustable actuator.
Hope this helps.

markda

796 posts

257 months

Tuesday 4th March 2003
quotequote all
M3EVO

I doubt you'll get an increase in boost using *just* a bleed valve, more than likely the ECU will just cut all boost as a protective measure. Even my 91/J Fiesta RS Turbo required a re-map before any more boost could be run.

If your looking to increase the performance of one of these engines, there are a whole range of ECU re-maps available from AmD, Jabba, Forge Motorsport and APR.

A friend of mine just had his VW golf done (at Jabba). The performance figure of 150 bhp is apparently quite a modist one, even before re-chip his was running 162 bhp and after re-map was upto 220 bhp!

Apparently these cars are actually more efficient on fuel after a re-map for normal driving Obiously if your flat out everywhere then you'll get through slightly more.

Hope this provides a little insight in whatever it is you had in mind? Have you brought one, only I am sure i read a thread not long ago about an S2000???

-- Mark

M3EVO

Original Poster:

1,564 posts

256 months

Tuesday 4th March 2003
quotequote all
No the question is for a friend of mine who is looking to purchase a Seat Cupra. I drove the S2000 and it didnt really light my fire so to speak so the wife and I are still in limbo about what to do.

Thanks for the reply.

funkihamsta

1,261 posts

262 months

Wednesday 5th March 2003
quotequote all
I whopped a bleed and relief valve in line to boost 7 to 11 psi using the stock wastegate actuator. Holds boost very well and no remap required. (Engine management is Bosch LH2-Jetronic with EZK ignition).

M3EVO

Original Poster:

1,564 posts

256 months

Wednesday 12th March 2003
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What did you use to acheive this??

funkihamsta

1,261 posts

262 months

Wednesday 12th March 2003
quotequote all
There's an article on the net regarding a bloke who did the relief valve followed by a bleed valve on his S3 Audi.
I will have a look for the original article (i printed it out somewhere) but if you were to do a google search l'm sure you could turn it up in the meantime.

markda

796 posts

257 months

Thursday 13th March 2003
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funkihamsta

I dont suppose you have the URL for us yet? I am interested to see how this is achieved without the ecu flagging the extra boost as a fault and switching on the engine warning light... What model and year of car did you try this on?

I assume you connected a boost gauge as a tempary measure to adjust the bleed valve to regulate the boost to just 11 psi. Did you try anymore boost???? or find the cutoff point?

--Mark

funkihamsta

1,261 posts

262 months

Sunday 16th March 2003
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forums.audiworld.com/tt/msgs/781027.phtml

for starters. This isn't the url l was referring to however. I'll try to find the original one later today.
If you have a boost gauge in car then the whole process is not really risky, as long as you take the bit at a time approach, and don't try to save time by making large adjustments to either valve. I found that l was not able to get a responsive enough RN bleed valve (just ended up with very dodgey oscillating boost levels) and returned to the good 'ol brass t valve. This works very well. The relief valve seems to give a stabilty to the boost that would normally fall away under wastegate creep. It also give vicious spool up, again because there is no wastegate creep.

My car has a fuel cut boost protection at about 12psi which l studiously avoided testing out!

funkihamsta

1,261 posts

262 months

Monday 17th March 2003
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www.autospeed.com/A_0670/P_1/article.html

It was an audi S4.
You'll need to specify far weaker springs for the diaphragms than is normally available off the shelf. These valves are used for compressors and other large bits of machinery.
I couldn't get the set up as shown in the article to work. The bleed valve part did not seem to dump air, simply scale down what was presented to the wastegate. This did not work for me, and l couldn't get away from oscillating boost levels until l dumped it in favour of an infinitely less sexy brass bleed valve followed by the releif valve as used in the article.