On my 93 wrx, which i assume is a td05, the lag seems very prolonged, i dont get full boost until about 4.5k, but i can hear the turbo spooling up from about 3k, is this right?? i suspect i have a small air leak anyway, pre turbo, but i cant find it. Is there anything i can do to bring the lag time down. Its kinda handy in a way because it makes the car very easy to drive sensibly, but at the same time if i want to get anything out of it i have to make lots and lots of noise!! The noise in itself isnt a major issue, i didnt buy it cos it was quiet and understated! However, i would quite like the boost to come in a bit earlier. I have an mr2 aswell and that hits full boost 1bar by 3k, and i dont think there is a huge difference in size.

thanks Mike

 

does sounds like you may have a leak somewhere and that may be causing it, one way to bring th elag down is a remap, but i'd cure the leak before doing that

 

Too loose bost, the leak is more likley post turbo, although it could be back into the inlet (say a leaky BOV), a TD05 should be on boost by 3K rpm, and once boost starts to build it should go just about straight away to full boost.

If your leaking boost to atmosphere you will also be overfuelling (for the airflow your leaking) which will do nothing for fuel economy, power or the state of the engine and cat etc!

MR2's are a smaller turbo (slightly) and are a shorter manifold and twin scroll, so even if it were the same size it would come on boost earlier!

Simon

 

Are you still running a standard exhaust? If so, my 93 WRX didn't come on boost until around 4k rpm. This wasn't too much of a problem when pushing on, becuase the engine / turbo will happily work to 7k rpm, and gears were nicely spaced to keep the engine above 4k.

However, a decat will lower the revs where the boost starts to build by around 500rpm, and enable a slightly more relaxed level of driving (always needing to be in the right gear before overtaking started to become a bit tiresome).

 

thanks for the replies, its decatted and running a 3 inch pipe to the exhaust, the dv wasnt leaking, i have since put it on the mr2 cos that one was leaking! i have the intercooler off now and the associated pipework so i will be checking that, it doesnt make full boost straight away, it climbs to about 0.5 then shoots to full, over about 500rpm. the turbo feels ok, there is no shaft play and it doesnt smoke, there is a tiny, i mean tiny amount of oil in the intercooler but nothing to make me worry. I have just put a z4 ecu on so i am gonna see if that makes a difference when i get it running again.
It was over fuelling like mad before it broke, maxed out the emissions machine, 9.99 across the board!! i have changed the lambda, but didnt help and i have since changed the coolant temp sensor. Hopefully that should cure it.
But as for the boost, i am not sure, i will have to check the pipe work, i know the feed to the turbo was split, and i have done a bodge repair with self vulcanising rubber tape, which should hold it, but i might replace that and see where i stand. the only other place is the turbo to intercooler, the intercooler to manifold is fine.
Thanks