After the Flash Tune - Add a Dump pipe

[Timbo]

Since the Sydney dyno day in April, I had a 3" 'dump' (turbo outlet to cat) pipe fitted by Raff and Neil at Fyshwick Exhaust Centre.

At the subsequent ACT dyno day last month, my l'il Pog poured out 135KwATW; but I also recorded 107KwATW when I switched to the 'stock' REVO tune using the SPS. Hmmm.....what did it all mean

I have to admit that despite the large number, I was highly sceptical about the dyno results of the recent event here in Canberra, and decided to verify against another dyno where I had had earlier runs

Here's the sequence of dyno charts:

This is the first run, at Mainline in Sydney in April. Running VPower 100 and a 100 tune


Then, the infamous ACT dyno day. Here's what the sheep's entrails produced for me (again, VPower 100, 100 tune


Puzzled, and disbelieving, I took my car back to Mainline....and here's what it shows (same fuel, same tune)



Let's leave aside the absolutes: it's the deltas that impress me. Adding this small mod to the exhaust system gains 11-12Kw ATW in a chipped car...I'm happy =)

BTW, I ran the REVO 'stock' tune on the Mainline dyno last week, for 97KwATW. Other stock Polos seem to be around 93Kw....so maybe there's 5Kw in the dump on an unchipped car...or maybe it's the 100 fuel....or who knows how stock the REVO 'stock' tune is.

For your information and comment

[Spec83]

Was this an off the shelf part or a custom dump pipe??? What was the approximate damage to the wallet???

[ACTGTI]

I just noticed that the Mainline dyno has you running in 3rd gear, I'm fairly certain the ACT one was done in 4th gear. Would that make any difference?

Anyway, nice gain.

[Timbo]

Answering some questions:

This was a custom 3" dump, built for me by Fyshwick Exhaust. Cost less than $500. It runs from the turbo outlet ball joint to the stock cat (ie, stock cat retained)....I'll post a pic sometime

GT3, I don't understand your question. I have deliberately posted results that are as close as I can get to a controlled environment, with the dump pipe being the only change....so I think it is fair to attribute the gain to the dump.

ACTGTI -- the use of a different gear can be argued to affect results. That's why I went back to the original dyno. In any case, with dynos, the key is to observe the deltas achieved by different mods, not the absolute numbers.

The evidence above suggests the mods have achieved the following power gain deltas:

- a 32% power gain at the wheels from the REVO flash over stock
- a further 9% power gain at the wheels by adding the dump pipe to the REVO flash....giving a total power gain from all mods of 44% over stock

It may be that there is some gain from the dump for a stock car....possibly 5%....but I don't have a real before "stock' run to objectively support this (ie, FLOODY's car ran 92KwATW on the Mainline dyno back in April; my REVO 'stock' tune with the dump is 97KwATW)....so I don't want to suggest to anyone they'll get great gains just by adding the dump to an otherwise stock car. I am pretty sure the real benefit requires a flash tune of some type.

[Timbo]

Timbo, there is quite a difference between 3rd and 4th on a dyno, on a pogo that would be approx 5kw

I don't understand why that would be the case. Power is power is power; the dyno computer should just convert is back to a common base.

If there is 5Kw, how can the close relationship between the 2nd sheet above (run in 4th) and the last one (run in 3rd) be explained?

Why I said I am "pretty sure" about the need for the flash is the obvious logic: a flash tune will, among other things, increase boost; a dump pipe will enable that boost to be achieved and used more easily

[Timbo]

I had a few PMs from people, which indicate some confusion as to why I made this post, so I will post publicly my most recent reply, hoping this will clarify my motives.

I am a keen advocate of information sharing on these forums. It helps people make good mod investment decisions, avoid making the same mistakes, and identifies some 'best practices' in modding certain cars. I am not trying to be the biggest ***** in a p!ssing contest!

In the case of the Polo, my point -- supported by some good objective data -- is that you can get excellent power output improvements through (a) a flash tune....and I couldn't care which one...I went for REVO because no one seemed to know much about them, yet REVO's credentials seemed as good as anyone else's and (b) a custom dump pipe (rather than a full exhaust)

In my case, these two mods have cost me less than $2k. This is a key point given we're discussing a $27k car. I understand 135KwATW is about the output limit of the KO3 turbo, so any gains beyond that will be relatively expensive for not much gain --- and, in any case, traction is now a bigger limiting factor!!

If my replies above seemed defensive, this was not my intention, but simply because I just wasn't quite sure people had read and understood my original post, as some of the issues raised were addressed in the original post (ie, I was using the same fuel and tune in all three).

Actually, I have a lot more data, but many people may not understand it if I post it (hence it may confuse), but I am more than happy to share it with people who are genuinely interested and understand the concepts. The data includes boost pressures and injector duty cycles as well as AFRs for the REVO tunes.

I am aware of other Polos with tunes and exhaust mods....all being full exhausts. In fact, they are making, at best, the same or less power than mine (ok, that's "according" to different dynos )-- my point again is not a p!ssing contest, but to identify further evidence which seems to confirm the early work Guy Harding did on Polo exhausts: the major restriction is in the OEM dump pipe; the rest flows pretty free (or at least as free as is required by the KO3 turbo -- it may be different with a KO4).

In conclusion, based on the evidence, this I believe : if you are modding the Polo for better performance, you will be well advised to spend your money on a flash tune and a dump pipe.

[awestonvp]

Timbo, great objective data to have, thanks for posting!

[Vieussuex]

Nice timbo really good results.
Want to group buy some LSD's

[ryan_GTI]

damn 135kw power figures is definately impressive with just the flash tune and a dump pipe..! well done!

... i've seen dynos of cars with a branded TBE and a flash tune only making about 125-130kw; but that also comes back to the different environment and dyno

[Timbo]

Nice timbo really good results.
Want to group buy some LSD's

Thanks Ash...yep, group buy on LSDs could be the go...as long as we can persuade Seb or Derek or someone to give a good rate for fitting

damn 135kw power figures is definately impressive with just the flash tune and a dump pipe..! well done!

... i've seen dynos of cars with a branded TBE and a flash tune only making about 125-130kw; but that also comes back to the different environment and dyno

Thanks ryan...actually, you've hit the nail on the head. There's more than a few vendors who are keen to sell you a branded TBE....for $2.5k+...+ fitting! I'd really want BIG gains for that

But perhaps this might stir someone to produce a reasonably priced dump + sports cat for the Polo......allow, say, $600-$700 and it would be hot mod...for everyone.