What boost levels on Stage 3 are S4 oweners running!

[saf]

Leading on from Blue Thunder's interesting thread on boost leaks,

Would like to know what boost levels people with Straight Plain Jane K04's are running. Please state whether you are runnign with or without compression dropping, manifolds any RS4 inlet mods etc.

As memory serves me, the ideal that one shoud be running on stock compression is 1.6 bar tapering down to 1.3 bar. / 23psi to 19psi.

With usual compression dropping, 1.7 bar to 1.4 bar. 25 psi to 20psi roughly.

Use this converter if you need to:

http://www.centauro-owners.com/articles/psibar.html


Please comment on your boost levels if you know them and please also comment on how you got your reading, (via boost guage, or if you was told etc.)

Doug says that you should run 22 psi peak to 18 psi in Blue thunders Internal boost leak thread.

Why ar epeople stating they are runnign near 2 bar then?

[Blue_Thunder]

Well, just done my first logs and I am getting a peak boost only a fraction over 22psi (22.34).

I've got RS4 Airbox, MAF, Y-Pipe, hoses, coolers and injectors.

[mattsimis]

As per other thread 26-28PSI (its hard to tell 26-28 on my gauge). Ive mailed Doug about this after getting the remap (MRC) and he asked me to get a Boost Gauge to confirm. Which I did, and thats what it says. I mailed again but didnt get a reply, put it up here too several times and didnt note any specific response suggesting its dangerous (it is high obviously). 26.5 PSI is 1.82bar, Ive a feeling it closer to that under normal operation.

Incidentially it only boosts so high when Im holding it in 3rd and Ive never held it so high for more than 3sec. Im also running Water - Methanol Injection.

[saf]

have your turbo's always been recons?

why did you decide to go with the rs4 air box maf and y pipe for using stock heads?
I wouldnt have thought it would make much difference, but ive been contemplating doing it as a mod later on after ive had stage 3 for a while. My cars waiting to be upgraded at the moment. Waiting on parts.

someone mentioned that refurbished turbos have a habit of failing. Not sure what your view is on this.

Your turbo's should not be stressed at all with this boost as this is what stage 3 RS4's are running and I heard on only one fail. For this to happen toy ou nearly three times now is not good.

Back to the boost. Your peak boost is under 1.5 so should be fine. Unless they havent been rebuilt properly and thats why theyare whining.

[mattsimis]

Umm, is that reply meant in this thread Saf?!?

[Blue_Thunder]

Don't think you need to worry about your boost Matt, water-methanol injection allows you to run higher boost because it reduces the chance of pre-ignition by lowering IATs.

[saf]

no not totally, but as Blue was here I thought why not.

Julian (S4TAN) gets about 27 - 28 psi peak on his boost guage at times too. Not sure what its tapering down to though. Maybe the boost guages are faulty?

[Blue_Thunder]

Julian's been fiddling with his N75 though. Infact didn't he replace it for an RS2 unit?

[saf]

Don't think you need to worry about your boost Matt, water-methanol injection allows you to run higher boost because it reduces the chance of pre-ignition by lowering IATs.

Interesting. But is that controlled boost by the ECU purposely maped for the methanol injection?

[mattsimis]

Controlled by the ECU, but it basically acts like high Octane Fuel, keeps things cool (stops the ECU calling for Fuel "dumping") and should infact allow higher boost levels safely.

[saf]

Nice. Learn somethign new all the time.

You using the Aquamist kit?

Yes youre rght Julian is using the RS2 N75. I dont know much about using the RS2 N 75. Sounds scary.

[S4TAN]

RS2 N 75. Sounds scary.

Yes - it's not "recommended"* ...

* - but then neither is drinking, sex or smoking - and they're all good fun!

[saf]

RS2 N 75. Sounds scary.

Yes - it's not "recommended"* ...

* - but then neither is drinking, sex or smoking - and they're all good fun!

Drinking, driving full boost on your S4 whilst getting friendly with a lass and a ciggy of some sort stuck in your mouth all at the same time???

Now that is scary!!!!

[mattsimis]

Nice. Learn somethign new all the time.

You using the Aquamist kit?

Yep, just the basic 1S version. I just tested it again, definately getting 28PSI, on 95Octane with Water-Meth Injection. I also have the IPP I/Cs. Tests didnt favour them based on the fact the RS4 OEMs cooled better, but it seems the IPPs have less pressure drop than the RS4s.

Since my Aquamist is helping the cooling, I get the best of both worlds: low heat and minimal pressure drop.

However, Im totally open to you guys scaring me with warnings.. is such high boost symptom of anything bad?

[saf]

Who mapped it?

Mgiht be best to ask them, if youre blowing hot air instead of running in the efficiency zone of the K04 compressor map.

The higher the boost the easier it is for your turbos to pop right?

Im under the impression that K04's are good for 1.7 ish, no higher.

Im waiting for the likes of Doug or Mihnea or anyone else tha has far more knowledge than me to comment.