TurboXS Dump Pipe and Recode Tuning for Golf R

[dave_r]

I seem to remember APR before releasing their unit conducted tests using both designs, and found the divorced set up superior.?

I think you need to do your own testing. You like to change wheels and intakes more than socks, why not DP's as well

[parso_rex]

Trying not to start a s@#tfight . That MRT article really applies to the TD04 and VF series turbochargers used on the rexies both of which have a pretty ordinary wastegate flapper position relative to the turbine outlet flow. The problem with these is that the wastegate flap opens up in the direction of the turbine outlet. It forces the gasses from the wastegate directly into the gasses exiting the turbine and its not good at all.

This isn't the case for the K04's, as you can see from the pics above it opens in opposite direction. It will never be an issue.

The problem with many divorced setups (and no I don't mean this one think the Subaru once again seeing as that's what is being mentioned atm) is that when the wastegate flap opens the exhaust gasses hit the wall of the tube which hurts flow badly leading to boost control issues as the now less effective wastegate tries to get things back under control. You have to modify the tuned file to make the wastegate flap open to a much larger angle than it was previously usually by reducing values in boost solenoid duty cycle tables.
The K04 though is a bit different, its recessed slightly and the splitter is forcing it down the tube to some extent and it seems to work otherwise they wouldn't be selling them, of course the tuned file would have different wastegate duty cycles to accommodate this - and it is too !!. Superior - no chance but that's just my opinion I have to tune a number of cars so If I don't have to radically modify one bunch of maps then the old Keep it simple rule works for me. All these options including custom are better than the stock one, lets leave it at that.
The TXS dump offering is pretty good so I'll l be using them for now but I still need to find the best option for a mid and rear section so
I'm still looking.
I have another R coming in the next week or two with some nice non-rice mods APR pump, Big FMIC etc so we'll see how we go with that too. I believe Zbeast will be getting a pump soon too so we can finally get some decent boost happening down low

[Corey_R]

Thanks for the feedback parso_rex. For what it's worth, I wasn't trying to start a "s@#tfight" either. Neither am I saying that the Turbo XS is bad - you already know that I defended it previously against some people attacking its credibility. I really only started posting on this line of discussion as I believed the "mouse drawn red marks" on the photos which were indicating that the turbine exhaust flow of the K04 is blocked by the exhaust flange on the APR DP to be incorrect and misleading - but that is no reflecting on you or Turbo XS

[parso_rex]

Hi Corey,no I didn't take it that way at all and I know your fairly balanced about all this stuff its just that usually a few people get upset if I post anything that different to what they have assumed to be normal practice.

[zbeasty]

I wasn't trying to start a s@#tfight either so sorry if that was the impression. If you have a look at the divider on the MRT video it is very thin. Given the heat that a turbo is subjected to I would actually be concerned with the splitter disintegrating over time with heat cycling. There is only a very small gap between the turbine outlet and the wastegate on the K04. To put a splitter in would mean that you would again have to use very thin material which would not stand up over time and end up destroying your cat converter. One thing that you can't really see in the photo is that the diameter of the turbo where the turbine is is actually larger than at the flange. The red circle on the photo that I loaded indicates where the pipe would be if you could get a straight run. If someone is up for modifying the casting of the outlet they could get the full benefit of the divorced DP because you could fully isolated the wastegate from the turbine flow. The only other option is the external wastegate which means another turbo because it would be cheaper than modifying the K04.

[dave_r]

At the risk of de-railing the thread any more, what are the other options out there? Miltek's item looks to be a bellmouth. Who else makes one for the R? (Maybe need a sep DP topic?)

I been doing lots of searching of UK sites but really struggling to find a lot of off the shelf products for the cars to be honest. Given how long the car has been out in Europe, I'm really surprised there isn't more info from people who've tried various options before.

[zbeasty]

The only off the shelf options seem to be APR, Milltek and TurboXS. Given how long the S3 and R have been available in Europe I'm surprised there aren't more options either. I think there are a few cat back systems but not TBE's. I think the biggest issue we R owners face is that we have a MkVI with a MkV motor with a different turbo. The market probably just isn't big enough. Even Forge reckon they haven't been able to get their hands on an R to work out if their twintake and twintercooler will fit.

[Corey_R]

There are actually heaps of products out there. We found at least 10 products back ages ago in one of the threads. Maybe someone can remember where those posts were. Many are brands which are 1) not available here, 2) people have never heard of, 3) are from europe, 4) cost basically as much as the APR stuff by the time you got it here :/

As I mentioned before, Milltek are unfortunately NOT a DP option - only a TBE option. So in general availability in Australia right now for downpipes, you only have two options, APR and TurboXS.

[dave_r]

Yeah I'm sure we've been though it before but I can't find the info. Supersprint are bloody expensive, I found them. Even searching the OzAudi forums nets little info.

But while the Milltek has to be done TBE, the full system is $2k before freight. Now I know it won't be cheap to ship but it would most likely end up around the same price as the APR DP so pretty good value (if you're not going the APR route that is so the software has no relevance)

[Fab_R]

Yeah I'm sure we've been though it before but I can't find the info. Supersprint are bloody expensive, I found them. Even searching the OzAudi forums nets little info.

But while the Milltek has to be done TBE, the full system is $2k before freight. Now I know it won't be cheap to ship but it would most likely end up around the same price as the APR DP so pretty good value (if you're not going the APR route that is so the software has no relevance)

Bank on about $300 via FedEx, which still makes it a reasonable price landed!

[Guy_H]

I wasn't trying to start a s@#tfight either so sorry if that was the impression. If you have a look at the divider on the MRT video it is very thin. Given the heat that a turbo is subjected to I would actually be concerned with the splitter disintegrating over time with heat cycling. There is only a very small gap between the turbine outlet and the wastegate on the K04. To put a splitter in would mean that you would again have to use very thin material which would not stand up over time and end up destroying your cat converter. One thing that you can't really see in the photo is that the diameter of the turbo where the turbine is is actually larger than at the flange. The red circle on the photo that I loaded indicates where the pipe would be if you could get a straight run. If someone is up for modifying the casting of the outlet they could get the full benefit of the divorced DP because you could fully isolated the wastegate from the turbine flow. The only other option is the external wastegate which means another turbo because it would be cheaper than modifying the K04.

zbeasty,

can you please let me know your engineering credentials (especially those relevant to exhaust design). I mentioned on another thread, I would be very happy to test one of your downpipes, side by side with our downpipe, I'll even pay for one, but would like a money back guarantee if we don't get the same wheel increase you claim with yours.

You are claiming 28.9 all wheel KW gain over our pipe, (no calibration change) - do you think that is repeatable?

Do you understand where we get our quicker spool up from divorcing the wastegate gas? Do you know what speed the exhaust gas exists the turbine & the wastegate & why its beneficial to separate them? (let us know what speeds you calculate @ 20psi, that will keep it simple).

This is a well proven product that has been sold into at least 10 countries around the world, and making an average of 15 all wheel HP with APR software (over a stage 1 tune). Your dyno is showing an extra 40 whp (add that to our gains & you are getting 55 hp @ the wheels! - that's the most incredible gain I have ever heard of).

P.S. - Have you measured the cross sectional area of your turbine wheel & the dump pipe? I can see you have drawn nice red circles, how about you put some dimensions on them?

[parso_rex]

I think Zbeast made a mistake posting that figure (did he post that here anywhere??) but to be fair I think he'd just gone off what he thought was on the car at the time. Looking at that I can tell It had a tuned file in there and its plainly obvious but at that time we had been jumping between various files stock and modified while we tried a few things to skirt round the stock HPFP issue prior to the dyno day. I think if you look on the TXS site they mention much more reasonable figures but I can't be ar$ed looking atm
A dump pipe - anyones dump pipe for that matter, only makes a gain if there was a flow related problem in the factory setup. I wouldn't lose any sleep over it nobody really seems to worry about this stuff it would seem

[Guy_H]

This is a quote from another frum that he has posted these pictures & results on:

The tune that was run was the same both times, the only difference was the change from the APR to the TurboXS downpipe. The red circle on the APR shot was put there to show where the pipe should be. The problem is that the outlet flange on the K04 is offset to the internal outlet for the turbine. To do the divorced pownpipe you have to compromise the flow of the turbine and as you can see a fair section of the outlet is covered by flat plate. On something like a GT series or some of the older Subaru turbos you can get a proper seal on both the turbine and the wastegate but on the K0 series you can't without modifying the housing significantly.

Fairly convenient he forgets some of the information.

[zbeasty]

zbeasty,

can you please let me know your engineering credentials (especially those relevant to exhaust design). I mentioned on another thread, I would be very happy to test one of your downpipes, side by side with our downpipe, I'll even pay for one, but would like a money back guarantee if we don't get the same wheel increase you claim with yours.

You are claiming 28.9 all wheel KW gain over our pipe, (no calibration change) - do you think that is repeatable?

Do you understand where we get our quicker spool up from divorcing the wastegate gas? Do you know what speed the exhaust gas exists the turbine & the wastegate & why its beneficial to separate them? (let us know what speeds you calculate @ 20psi, that will keep it simple).

This is a well proven product that has been sold into at least 10 countries around the world, and making an average of 15 all wheel HP with APR software (over a stage 1 tune). Your dyno is showing an extra 40 whp (add that to our gains & you are getting 55 hp @ the wheels! - that's the most incredible gain I have ever heard of).

P.S. - Have you measured the cross sectional area of your turbine wheel & the dump pipe? I can see you have drawn nice red circles, how about you put some dimensions on them?

Guy

No engineering or plumbing (fluid dynamics) credentials here but I am a bean counter so know how to use formuals. We were doing logs when I ran the numbers so I'll see if I can get IAT, EGT, MAF, MAP and AFR readings to do an exhaust flow calc at peak power. I'll have to make some assumptions about volumetric efficiency but I should be able to get a close enough number. I'll then have to ask either VW or Borg Warner what the pressure differential across the turbine is at that flow rate then I should be able to work out the exit speed of the exhaust gas from the turbine. I'll also need to know how far the wastegate is open at that point so I can work out cross sectional area and therefore the increase in pressure of the exhaust gas as it flows from the exhaust manifold through the wastegate and therefore increases speed. Then we can compare turbine exit speed with wastegate exit speed. I assume that there is a difference but how much (or how little) I don't know.

Ultimately though it is a combination of exhaust gas volume and speed that will affect performance not just the speed with which it is exiting the turbo. If you can't get all of the gas out it will increase back pressure and the ability of the turbo to spool. If you don't think the big section of flat plate in the middle of the outlet on the divorced design is reducing flow then we have a difference of opinion. I don't have the APR DP in my possession but I'll measure the cross sectional area of the twin pipes and see if it matches or exceeds the cross sectional area of the single pipe next time I'm at the workshop. I'll also be able to tell you what the diameter of the red circle is because it approximates the pipe on the other side of the flange. If you have a set of calipers handy and a pipe in stock you could probably tell us much faster though. The reason for boosting faster against the standard set up is that the factory 800 cell cat that sits at the exit is much more restrictive than the APR DP its just that the TXS DP is even less restrictive.

The other point you need to remember is that given this motor has electronic boost control the wastegate should only be open when it is trying to control the boost. If you aren't making the desired boost then there will be no wastegate gas flow to interrupt the flow from the turbine.

As to gains it was 201kw TXS vs 181kw APR which is 20kw or 27hp on my car. My car was never dynoed with just a tune so I don't know what it made therefore I can't comment about gains vs stg 1. My stock dyno run however was 150kw so I had a 30kw increase with your DP and the Recode tune. Does that sound about right for a Stg2 car? At the Sydney dyno day Lima's APR Stg1 S3 made 179kw and my car made 198kw with the APR DP and this tune. That is a 19kw difference which is slightly more than 15hp. The other APR 2+ car on the day also made 198kw (althought he has a Milltek exhaust). My car might just be a freak of nature and produces good numbers but they are repeatable. It did the 181kw or there abouts with the APR DP and this tune on a couple of different days on the same dyno. I've only run it once with the TXS DP but I'm confident it would produce the same numbers (201kw or there abouts) on that dyno.

As for sales in other countries, what design do APR US use for their K04 cars? Are they going to be borrowing your design once the R is released there later this year/early next year?

By the way Guy I am not having a go at the quality of your product or anything. You came to market with something that has been seen to work on other designs and should in theory work well. The design of the K04 however does not suit the divorced downpipe because the turbine exit is partially shrouded by the housing and you can't get a large enough pipe to match the size of the turbine exit and the flow requirements. If you could modify the housing on the K04 so that you could use the same design DP as used in the Stg3 kit then I'm sure that the power differences wouldn't be as great as they are now.

[dave_r]

Good discussion, hopefully it stays civil.

Zbeasty, I know you did a few runs at WSID with the APR DP and tune at the time. Have you managed to get back out here with the TurboXS DP being the only difference? One would expect that the power gains being talked about would translate directly to better times/mph?