Uncontrollable Boost

[Fat-Tony]

id say bolt the orignal cat back in place if your after an exhaust restriction

[Romulus]

  ByeByeRB26 said:

the exhaust is off the turbo difilipo 3 1/2" dump with a 1" screamer pipe then a 3 1/2" hi flow cat and twin 2 1/2" from the cat to the back

I might have to bolt back on the original dump and then start with an 3 1/2" engine pipe off the origianl ford dumpdump

I never thought having no restriction could be an issue on a turbo car

I still want to make 350rwkw but just not everyday

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What kind of intake setup are you using? The stock intake and cross-over pipes?

Nizpro recommend a 3" cat with their Stage 2 Cobra kit for stock turbo's. I've installed the stock dump pipe on my F6, which then runs into a 3.5" dump and flows into twin 3" cats. With the Stage 2 Cobra kit being installed as I write this, the twin 3" exhaust is coming off the car and a twin 2.5" system is to be used from the cats back, in an attempt to build some restriction in the intake. If that doesn't work some 2.25" piping will be fitted in the system.

Edited 11/07/06 11:02 AM by M6 XR6T

[ByeByeRB26]

The whole intake piping system is now custom with intercooler and air box and battery swap over, all the factory cross over pipes have been removed.

Me 2 will have to try a different exhaust set up, I will put the factory dump back on and start the new 3.5" system off the factory dump instead straight off the turbo

hopefully that will solve the problem

[Eugene]

Can you say external wastegate?

Dont slow yourselfe down by building in a restriction, allthough easy enough with a thin stainless plate of the desired dia hole( to say drop it from 3.5 to 3 inch dia) between one of your exhaust flanges, leave the big pipes there and try that first.

otherwise, wire or clamp your factory wastegate shut, then fit a 45-50mm external wastegate into the dump pipe, still controlled by your factory setup, being driven by edit, this will allow much better control, it will dump faster (as goose said, a bigger hole is required when you get up there).

they are not too exp and are easy to fit, and would be cheaper than redoing a whole exhaust to build in restriction, as well as allowing the flow you want down low, but the boost control up top.

Just an idea.

I am hoping I wont have this drama, allthough boost seems to be controlabale at the moment.

I have as imilar set-up without the cooler piping yet, just waiting on a plenum, then its on.

[Romulus]

I think you'll find the cost of buying an external wastegate plus fitting and modifying the stock exhaust manifold outweighs bolting on the stock dump pipe and fitting a single 3 or 3.5 inch cat.

I do agree though it's a fine line between building a small amount of restriction in the exhaust and impeding performance due to a too restrictive exhaust.

[Xtreme F6]

oor u could just do what the geese suggested as this is quite simply the problem. You cant get the gasses out of that small waste gate fast enough to keep boost down to where you want it.

[F6 UTE]

I agree, get the wastegate hole ported and put a bigger swing valve on it. You have the upgraded spring to keep it shut, well you need a bigger exit hole to get rid of the extra volume.

Leave the exhaust in place as boost control will always stop you going further, and will have to be fixed eventually.

Personally, I'd go with Eugene on an external gate..

....

Just checked our favourite auction website.

38mm TIAL wastegates can be had for 350-380$$ About the same as a dump pipe, fitting would work out the same as rooting around with your exhaust that you lashed out good coin for..

Edited 11/07/06 02:19 PM by F6 UTE

[GOLDIE]

We are now running 350 rwkw's and do not have any boost control problems.

The turbo is standard except for 12 psi actuator,custom intercooler and piping.

The exhaust is 3.5 inch from turbo back to tail pipe with 2 mufflers that are straight though.

As I said there is no boost controll problems at all.

Ian

[Xtreme F6]

  GOLDIE said:

We are now running 350 rwkw's and do not have any boost control problems.

The turbo is standard except for 12 psi actuator,custom intercooler and piping.

The exhaust is 3.5 inch from turbo back to tail pipe with 2 mufflers that are straight though.

As I said there is no boost controll problems at all.

Ian

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yes but goldie what boost are y9ou unning down low as this makes all the differenance as does your max boost your willing to make