hahahaha in the first link, I didn't even know the car was running until he reved it up LOL. The RB Turbo back is a no brainer, I just wish I had a Turbo II LOL

 

lol, jason.... just lol on first vid in the end.

 

I have it and I love it and I've owned several exhausts:

2.5" Bonez DP into custom 2.5" pipes into HKS Dragger: LOUD
3" SSautochrome turbo-back: LOUD
3" RB turbo-back: perfect

any exhaust that is large enough will increase the amount of boost but ONLY the RB system keeps it quiet and streetable but nice at WOT.

I can't vouch for the 59hp increase (since I had the loud, open exhausts before the RB) but I can vouch for it's noise level.

 

RB is a nice quiet exhaust that flows enough air for a 500 HP car. How do I know? I basically did it!

 

Ive got it and love it. Very good quality construction and of course it looks good.

 

i dont know what you guys consider quiet, but mine is quite loud, especially at WOT. The FD RB exhaust is definitely much quieter, even with a full midpipe

 

The 59 hp gain includes removing both cats, where a large percentage of the exhaust restriction lies. RB FTW!!!

 

Quick question, not meaning to hijack...

I have a large 2.5" - 3" exhaust on my car right now. My boost is set to what looks like 6-7 lbs, *which, I believe is higher than stock*...but would adding a RB to my car increase my HP or still, or has that already happened?

I've never dyno'd my car *don't know where to go for that...* and I've never driven a regular stock TII, so I can't compare.

 

is your wastegate ported?

 

That' I'm not sure of. I didn't get much info on the car when I bought it last year. It's an 88, so I figured if I was going to push 7 lbs, I'd have to have it ported. I don't have any boost creep or anything like that....so would that mean it's ported?

 

maybe that's why you don't see a boost spike. Do you have a boost controller? any other mods?

I don't think the RB kit will give you MORE POWER, LESS NOISE most likely.

 

Uhh, I don't know of any other mods that are big. I have a cone filter, no emissions, I'm not sure how they raised the boost level at all. Don't you have to keep that boost controller on there to keep the boost raised? Boy, I think I officially REALLY hijacked this thread.. SORRY OP!

 

well if your stock boost controller is still plugged then you'll open the wastegate at ~6.5 psi. ( can't recall stock boost on the S4's) and if it's got a ported wastegate you won't see the boost spikes that yield the HP that RB claims.

If you get a boost controller you can increase boost, get an FCD, fuel controller and maybe bigger injectors. You really shouldn't go past 10/11 psi on stock injectors. Maybe someone else can chime in and add/take away from my post.

 

I dont see more than 7.5psi at most with my rb. I have a ported wastegate, rtek 1.7 chipped ecu (built in FCD), 750cc secondaries injectors, walbro fuel pump.

 

Oh, that reminds me. I was told it's got a walbro 255, and FCD....would that help? :p

 

it will help deliver fuel and prevent fuel cut but you're not boosting enough to hit fuel cut yet.

 

isnt the stock fuel cut @ 8psi for S4?

 

When does boost creep start to hit for s4 without a ported wastegate? I'm wondering if it was done *though I really doubt it, would be a good thing to know, haha*

 

you don't hit fuel cut because you're not increasing boost. IF your wg isn't ported than you hit 10+ psi which is ~1.4psi. past fuel cut and you NEED the FCD. IF your WG is ported than it's opening at the stock psi and you won't see any spikes. You have a boost controller?

 

I'm not 100% sure if I do or not...I've not seen one, but then again I have never seen one before. I figure I'd see it plain as day, though if I looked in my engine bay. Are they big and noticeable by the turbo?

 

One year old thread and still kickin-

I'm a simpleton and a newbie, so please use small words-

If I install the RB Rev II 3" complete kit, downpipe-to-mufflers, on a fairly stock S5 1990 TII, is the RB FCD the only other mod I'd need?

Or is a new fuel pump required?
Porting of wastegate required? (and if so, how hard is that?)
New Injectors required?
Anything else?

Airpump/acv is removed, K&N filter on intake, calm driving to and from work with occasional "off the line" high revs or passing situations.

Thanks for any help in my exhaust planning-
steve

 

For the car's safety/reliability port your wastegate (not real hard, but takes some time under to pull the turbo, remove the hot side, port, weld a bigger flap on (you should do that), clean, reinstall), upgrade your fuel pump, and upgrade at least your secondary injectors which will require some sort of intelligent fuel management. I use the Rtek 1.7, it works nicely and doesn't require tuning. I plan on eventually buying this exhaust, but it's $$$$! For now I have a custom (done myself) mostly open and larger than stock exhaust that works well enough for the moment.

 

So it's not a simple plug and go answer.
thanks

 

It's not absolutely necessary to weld a bigger washer onto the flap on s5 wastegates. The s5 has 2 ports as compared to the s4's one. Here's mine ported:



While you're at it as an option you can polish the ports as I did: