what boost should i get out of a normal 996tt

[cavanagh]

i am only getting 0.4 and 0.6 if i push the car what should i expect

[Glenn McMenamin]

I'm sure i've seen at least 0.7 from mine, any more than that and i couldn't take my eyes off the road to look anyway !!!!



For some reason, it does seem to vary from gear to gear

Only had it a couple of months though, and wife gets to drive it more than me

G.

[MOD500]

Think 0.7 is the max for a standard car with standard exhaust.

Boost levels can vary depending on the environment (temp, humidity, etc) though.

I am no expert on the 996, but could the ecu be in limp mode restricting boost due to some error code that has been triggered in the ecu? I know my 993 went in to limp mode when I had problems with the cats playing up.

HTH


Martyn.

Edited to say: I just had a look in your profile amd saw you are in Yorkshire, your office is very near me. I got our office photocopier from your company too! Small world. Mail me if you want to go for a run sometime.

>> Edited by MOD500 on Friday 8th October 14:21

>> Edited by MOD500 on Friday 8th October 14:24

[t urbo]

My previous car was a std tt and that used to hit 0.7.

I think if you are only getting 0.4-0.6 you should get it checked out. I agree that the boost varies on humidity,temp etc but not to that extent.

[cyrus1971]

.7 is absolute max and .6 is normal max. Conditions are important. Drive through fog this morning from Basingstoke to Newbury saw a rare .7 on my guage. 996TT is very linear and does vary boos for drivability reasons. The Australian (Steve?) at G-Force in Aylesbury is very knowledgable on the subject of boost design and related issues.

[ultra violent]

...that would be Chris and he no longer works there. Hot water law should tell you everything you need to know about boost...

[Marquis_Rex]

A couple of things, I wouldn't trust the gauge quite so exactlingly. It's difficult for it to be so accurate as it is looking at static pressures (not even absolutes), and we're talking about the difference of 0.6 to perhaps 0.7.
MOD500 is quite correct in that the Motronic FI decides (along with quite a few other variables) how much boost should go in , depending on other things such as fuel octane used, ambient temperature and humidity, volatility of the fuel used altitude etc etc.
However if the car had gone into some limp home mode you would surely know about it by the way it drives, there isn't an intermediate condition where there's a "slight-limp-home" mode.

[911 habit]

You might want to checkout a string I started a while ago:
www.pistonheads.com/gassing/topic.asp?f=48&h=&t=91642

Since then I've put a sports exhaust and airfilter on. This still allows 0.7 bar boost, however, it comes in 2-3k rpm higher now - which is a good thing

Next step is to chip it to get the safe max of 0.9.

Gerry