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The mkiv Supra Owners Club

Do we bother with dump valves anymore?


Nodalmighty

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I'm with jurgen, i'm running my stock recirculating bov. I've tried loads on my UK auto and all you get is stall between gear changes.yes it sounds cool but I've always recirculated for better pick up n smoother changes. You'd be surprised what the stock bov can handle

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I'm with jurgen, i'm running my stock recirculating bov. I've tried loads on my UK auto and all you get is stall between gear changes.yes it sounds cool but I've always recirculated for better pick up n smoother changes. You'd be surprised what the stock bov can handle

 

UK is diffrent as they are using AFM (air flow meter) whilst j-spec use MAP (manifold absolute pressure). and your EMS cant calculate for any loss of air whilst MAP just messure pressure and not flow.

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You need one if you run a decent amount of boost or you will split the IC/blow off pipes, HKS racing is the only one ive found that opens quick enough, turbosmart is rubbish, tial is pretty slow an all.

 

Jamie I am considering the twinwaste gate turbo kit from garage whiffbitz which comes with two turbosmart wastegates, and I wanted the valves to be from one brand so wanted to change my greddy type-s bov for an turbosmart raceport aswell, did you had the turbosmart valves in the past, as I heard they were also very good quality valves. I never heard they were rubbish.

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Jamie I am considering the twinwaste gate turbo kit from garage whiffbitz which comes with two turbosmart wastegates, and I wanted the valves to be from one brand so wanted to change my greddy type-s bov for an turbosmart raceport aswell, did you had the turbosmart valves in the past, as I heard they were also very good quality valves. I never heard they were rubbish.

 

I still have the turbosmart fitted, the delay between that opening and the HKS opening is laughable, the turbosmart is very slow to open,

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I still have the turbosmart fitted, the delay between that opening and the HKS opening is laughable, the turbosmart is very slow to open,

 

Oke good to know, thanks for letting us know, so better stick with an HKS Racing type II bov then.

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If intercoolers can split from not running a bov does this happen in motorsport? I'm assuming in wrc and such like they dont run as high a pressure so maybe they dont have to deal with it, intercooler's must be rated to more than 1.6bar surely?. What about I/C pipes in motorsport, do they weld them together or do they use silicone couplers like us? I was looking at a synapse bov but then I'm not to sure about the ptshhhh sound around town, everyone thought I was trying to race them when all I was doing was accelrating to get into lane or something.

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I can't say for any other car, I only know what I've seen with single turbo supras.

 

 

Oke good to know, thanks for letting us know, so better stick with an HKS Racing type II bov then.

 

I would, also a heads up on the turbosmart wastegates, the paint fell off mine after 1 week.

Edited by JamieP (see edit history)
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Sums up what I would do if I had a turbo'd car. My rule of thumb is, "unless you know why you should perform a modification that changes a car from standard spec, then don't."

 

Stock TT supras have bov's as standard so thats your theroy blown out of the water.

 

No Jamie. If I had a stock TT supra, then what I said dictates that I'd need a damn good reason to remove it. If I didn't have such a reason, I'd keep it on. :)

 

I would trust that Toyota's R&D engineers knew what they were doing when they decided the standard TT car needed a BOV.

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We will have to agree to dissagree here as Ive run with no BOV loads of times, i had to run the black car without and even at over 2 bar never had a problem, no pipes blown etc. Daywalker wont make any difference as the shift is full nthrottle so there is no chance of stall. I know CW also has not run them on any of his turbo cars. Also over the years the amount of cars Ive had of all makes running around with seized BOV's both stock and aftermarket is pretty large, these all ran fine with the ownwers none the wiser.

Edited by dude (see edit history)
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If I/C's are splitting and pipes blowing off it's more down to unsuitable I/C's and piping systems being used than no blow off valves, per se. If you DO choose to believe they help spool then you would certainly need a recirculating BOV to achieve any hope of this. A proper intercooler designed for the higher boost pressures a few here are running will not split, nor will pipework joined by proper Wiggins fittings blow off.

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Andy Frosts Red victor didn't run a dump valve and that was running well over 2 bar and 2600bhp. He did have about 5k worth of wiggins clamps on it though :)

 

Lyndon.

 

:)

 

RV2 had a Turbonetics "Godzilla" BOV

 

RV3 has turbosmart BOV's

 

Red Victor 3 is better, faster and meaner than its predecessor. It is also now powered by a turbocharged 539ci (8.8litre) GM Chevrolet V8. Look closely and you’ll find Turbosmart BOV and wastegates lurking underneath the bonnet.
Edited by JamieP (see edit history)
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I haven't had one fitted for years and I'm running full power bpu :) Not had a problem and its probably covered 30k miles without one. If my oem hadn't packed in I would still be running it, I have other things that need sorting that are financially draining so at the moment its having to live without one. I can see the point if you are running higher boost than 1.2-1.4bar but at bpu I'm not so sure they are a worthwhile investment unless you like the pffft noise. I would like to clarify that I am neither for or against but just stating the fact that running mine without hasn't caused any issues.

 

R.

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Much as I hate to disagree with CW... :)

 

Compressor surge is caused by too large a turbo (something ported compressor housings came about to combat) and the throttle plate shutting while on boost.

 

Now, bearing in mind Chris's assertation that a lot of garbage is written about BOV and stall/surge on the internet (and the fact that's probably true), I decided to leave the world of car tuning. I found these:

 

http://www.waset.org/journals/waset/v34/v34-2.pdf

http://www.gmrc.org/documents/GMRCSurgeGuideline_000.pdf

 

GMRC is the Gas Machinery Research Council. They certainly aren't trying to sell shiny BOVs, so I doubt there is any ulterior motive or recycling of previously-written-internet-garbage.

 

This is a quote from page 11 of the GMRC paper:

"Any surge event can cause severe damage to the thrust bearings, seals, and the impeller. The extent of the damage due to surge occurrence is somewhat a function of the compressor design."

 

The two papers show the amount of engineering that goes into industrial control mechanisms for gas turbines and the like, specifically to prevent surge. I can't see this amount of research, engineering, and capital expenditure being done just because someone read on a car forum that a BOV would be a good idea.

 

I'll continue to run a BOV :)

 

-Ian

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  • 1 month later...
If I/C's are splitting and pipes blowing off it's more down to unsuitable I/C's and piping systems being used than no blow off valves, per se. If you DO choose to believe they help spool then you would certainly need a recirculating BOV to achieve any hope of this. A proper intercooler designed for the higher boost pressures a few here are running will not split, nor will pipework joined by proper Wiggins fittings blow off.

 

True I am runing 1.6bar with no bov.

Never had an issue with splitting pipes.

I may fit one before I up the boost any more tho.

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  • 11 months later...

Just took the standard BOV off my BPU'd 1JZ.

 

Really for no other reason than I could make up a blanking kit for it out of a few bits lying around the garage so it cost me nothing to do it.

 

Won't get a chance to test it until my next trackday on the 10th of May but I'll bring the stock set-up with me, just in case.

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