RS2 Bottlenecks

[murat]

Tried to search if there is a similar topic.

What are the bottlenecks when modifying the stock RS2.

Rougly how much HP can handle

1- RS2 Turbo
2- RS2 Exhaust Manifold
3- Downpipe and exhaust
5- Intercooler
6- Intake Manifold
7- MAF
8- Stock Airbox

I am tying to prepare a route. This will help a lot.

[aRtiS]

There is only one bottleneck: finance resources available
Accordingly - anything is possible, up to 1200 HP from such a engine

Stock engine set: as much as I know - 400 HP, after rods have to be changed

[re2500]

I would say rods and downpipe are your first real bottlenecks.

[Sonic]

Not definitive, but hopefully this helps a little -

1- RS2 Turbo - 360-380 bhp maxed out, you'll want to look at a k26/27 hybrid for an OEM-k26 bolt-on or an alternative from other manufacturers which typically require changing the inlet and oil lines.

2- RS2 Exhaust Manifold - I think these can go up to about 500bhp, will probably do more but become restrictive. The best alternative is the direct replacement from Wagner.

3- Downpipe and exhaust - RS2 exhaust is 2.75" and i think limits above ~350bhp, i'd certainly be going for a 3" stainless replacement for anything more.

5- Intercooler - Not really a question of "how much hp can it handle" but people have made good use of the RS2 IC with it being completely drop-in. Most people seem to run larger for anything more than RS2 power (350bhp+). The Wagner intercooler is a good direct replacement.

6- Intake Manifold - Not sure of the limits, i'd expect quiet high as it's not so much a limiting factor, but you'll get better flow from a replacement like the Wagner reverse inlet manifold, which drastically reduces the length of inlet hose between the IC and IM.

7- MAF - Ross is running an RS2 MAF with his 450bhp setup, but has already snapped one. I'd suggest anything above RS2-power gets upgraded to Dmitri (prj) new RS4 combination.

8- Stock Airbox - I'm running an RS2 airbox with close to 500bhp (from initial estimates), and i'm not sure you'd want to take it might higher.

[Avantus]

Downpipe also only up to 350hp?

I still have the original downpipe on my K26/27 RS2, and Prj said it wasn't worth it... other opinions?

[Sonic]

As i say, it's not going to stop you running more, but it is going to become a restriction.

But please post your own experiences, that's what the forum is all about

[Rusty]

May be better to say what power / torque you want or what turbo you have in mind and then people can post up what they have and discuss the suitability of the RS2 kit for that requirement.

[murat]

I am not sure,
I am thinking of a GT/GTX
GT/GTX30R or GT/GTX3071 maybe
I prefer a bb turbo as early spoolup always help.

Any suggestions?

[Rusty]

So you're looking at 450-500bhp then? In that case, the RS2 turbo is not suitable.

Based on that sort of power requirement -

Depending on what EM and hot side flange you need / decide to use, you'll need to get the DP modified anyway, so might as well go for a 3" DP.

The RS2 IC is going to be at its limit for that power and the RS2 EM is going to limit what turbo you can use, so is worth replacing. If you replace the IC then you might as well go the whole way and get a short intake too.

Your clutch is also going to be at the limit and you'll be best off having the engine rebuilt to take the extra torque.

The RS2 MAF is also at its limit there, so you'll need to get it mapped carefully or upgrade with a kit like prj's.

Your RS2 injectors are also not suitable for that power, and you'll need to consider an 044 fuel pump too.

RS2 airbox can be modified to fit with some of the larger turbos but if you go for a tubular EM, you'll have to rework all of the inlet pipework.

Bassically, you're looking at replacing most of the parts to fit anything bigger than a GT3071 and allow it to make the power than it should do.

For lower power requirements or a k26/27 like Ross or Sonic have, you could retain more parts.

[Avantus]

As i say, it's not going to stop you running more, but it is going to become a restriction.

But please post your own experiences, that's what the forum is all about

The thing is that it's running good and I don't notice any problems with it... but
then again I don't know how the 3" downpipe would feel like
And I do have the Wagner ex mani and 3" decat from the stock 2.75" downpipe on.

[EspenW]

Out of the 8 stock parts that you list, the only parts that I don't run is the turbo and exhaust after the Cats.
The alcohol fuel boosts the numbers, though.
I recently snapped the MAF wire, so that is the only component that I'm worried about. They seem to go at airflows that produce around 450 true WHP.
440+ true hp at the wheels and 620+ true nm at the wheels, the less meaningful numbers at the flywheel are likely around 530-550hp and 720-750nm.
After seeing that my car is faster in the real world than a friends E85 650-680hp B4 Audi that is both slightly lighter and slightly shorter geared, I completely stopped focusing on peak numbers. Unless the car in question has a CVT or dual clutch gearbox that can keep the rpm right around peak hp, the fatness of the hp curve for the speed interval in question is what determines the outcome.

Stock RS2 IC and downpipe vs. aftermarket: Here is a post that I had in the VDR thread:


Here are two 3rd gear pulls that gave some surprising results back in the day. My RS2 on 99 octane vs a friends RS2 on the same fuel. Both had peak boost set by the same type Turbotech MBC at approx 1.8bar. Very similar turbos, but mine is a T04E50 with stage 3 wheel vs. Super T04E50 with Stage 5 wheel on the other car. Same KKK #8 hotside on both. The comparison RS2 had full 3" turbo back without cats, while mine has stock RS2 downpipe and stock cats with a 3" Milltek Catback. In addition, the comparison RS2 had Wagner IC, but mine has the stock unit. Similar Jonus developed software on both cars. Testweight was 3550lbs on mine vs 3850 on the other, so it had a better load for the turbo as well. Based on hardware, one would have expected the results to be reversed, but not so in real life during these tests. 18" wheels on the comparison car didn't help it, though.

[murat]

I can go with the stock RS2 Em with one of these

http://www.034motorsport.com/turbochargers-and-accessories-turbocharger-housings-turbine-housing-audi-i5-k24k26-style-for-garrett-gtgtx-turbochargers-p-22220.html

Of course, I know downpipe should be changed to a 3" one.

I already have a walbro pump in car. I will need new injectors, I know.

GT3071 or GTX3071, which one for ADU?