May 28, 2004
whats the stock boost on a 00 1.8T and whats the max it can go without upgrading turbo?
not sure about the stock boost, but there are 4 limits with turbos:
1) the engine compression ratio - there is a limit where knock with happen at any ignition setting - at this point you need to reduce the compression ratio of the engine to use higher boost
2) block and rod strength - above a certain torque (depends directly on boost) then the rods will break/bend or the block will be damaged
3) the intercoolers are usually crimped at the ends and tend to unwrap and explode above a certain pressure - most production cars have trouble above about 1.5 bar but this is only a rule of thumb
4) turbos produce more torque in the mid revs range, and their efficiency drops off higher up the revs range - outside of their optimum band they cant maintain boost - you get a great whallop of boost from 2500-3000 upwards until 4500-5000rpm then it trails off quite rapidly
if you set the boost very high, you get a big surge in the mid revs - most turbos can generate enough boost in the mid range to bend rods or blow up engines but then fade rapidly up the revs scale - from a practical point of view you use a boost pressure that is reasonably well maintained to give a good working revs range or you have to drop gears about 5k to 5.5k revs, and may go off boost a bit in the next gear.
the 1.8t engines are commonly run at between 1.35 and 1.4 bar generally but with smaller turbos the torque/boost will fade rapidly above 5.5k revs, and as much as 1.8 bar occasionally peak in the mid revs, although the intercoolers may go leaky above 1.4bar according to jabba.
Thanks Guys for you help.
Can I go above 8psi on a stock motor with no serious mods do just a DV valve.
I thought stock was at 9psi...
I really would like to turn up the boost just to see what would happen but I don't know the limit that the stock motor could handle. If stock is 9psi can i go 11 12 etc...
up too 14psi or will that plow something up.
You can get a electronic boost controller that hard wires in and you can turn the boost up and down when ever you feel like and it is designed for the drive by wire 1.8T engines..
Thanks alot my girl told me to buy it already and shutup. It was a wise choose and the feeling of boosting higher is great.
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