3B boostlevels stock and 280 bhp

[1975DCS]

Ok just searched through 500 hits about boost, but still not found...

What kind of boostlevels will you about to see on a stock or 280 bhp 3B engine. Please with a given gear or rpm as this is of major influence...

[Ross]

I can't say much about stock 3B's as I've never driven one. I understand that 0.8bar is about the max you should see, at what revs I'm not sure.

As for a remapped 3B, that I do have a little experience with

In 1st gear, I've never kept much of an eye on it as it goes so quickly, but around 1bar seems possible. 2nd gear, I've seen 1.4bar for a very period of time at bout 5.5k rpm. usually it needs a hill to load the engine enough to get to full boost in 2nd before it's time to shift again...

3rd-5th I hit 1.4-1.5bar usually from about 2,800rpm. I've seen as much as 0.5bar at 2000rpm and full boost about 2500rpm if you floor it from low revs. I dont think this is too good for the car though...

usually I see max boost (and it gets there pretty quick) flooring it around the 3-4k mark. Flooring it above 4k, it often doesn't get much more than about 1.2bar; I have seen 1bar at the redline once (!) but usually somewhere around 6-6.5k it drops off below 1bar and I shift.

Hope this helps.
Ross

[1975DCS]

This is very handy information indeed! I think mine is ok above 3500 rpm as I do see about 1.2 bar that falls to about 1.0 bar at about 6000 rpm.

In the workshop manual for the standard 3B I only found this information:
Push the pedal at 60 km in 4th (just below 1900 rpm) and when the engine hits 3000 rpm (96 km) it should be reading the following pressures:
Sea level: 0.78 - 0.85 bar
600 m: 0.84 - 0.91 bar
1200 m: 0.90 - 0.95 bar
1800 m: 0.94 - 0.98 bar
2400 m: 0.97 - 1.03 bar

[1975DCS]

Extra info needed

Lately I only had 0.7 bar overboost at 3500 rpm and only 0.4 bar at 6000 rpm.
It turned out to be not getting full throttle.
Now it is 0.95 bar at 3500 and 0.55 at 6000 rpm. Somehow this still seem low for a chipped 3B, especially if the original is supposed to go 0.80 bar all the way (is it?)...

[s2 rich]

hi m8 my 3b is 313 bhp and that was at 6800rpm in fourth if that any help

[1975DCS]

Cheers man! But how do get this so high with the std turbo? 313 and 6800 seems quit high for stock turbo, according to what I have read on this forum before... Sure you not got some secret turbo?

[LHD_Kid]

Mine is a mapped 3B, 1.4 or just over (less than 1.5 though) bar at about 4000 in 3rd, dropping to about 1 bar by 6200-6500
appprox 280 BHP
any use?

[1975DCS]

Do you perhaps have an 3B mapped with a different mapsensor (250 KPA or so)? So you can have chipped ABY results...
Good figures!

[LHD_Kid]

mine is 250KPA map sensor, mesh cone filter on dahlback intake, also with aluminum airbox and cold air feed. decat and Scorpion exhaust... standard wastegate spring....

[audiman]

Lately I only had 0.7 bar overboost at 3500 rpm and only 0.4 bar at 6000 rpm.

No 3B's had overboost.

[1975DCS]

I think that extra overboost on yours will make it much nicer to drive... How much torque? But I think I should at least have the 0.95 at 5.500 rpm too... Otherwise I don't have 275 bhp I think...

[1975DCS]

No 3B's had overboost.

I know there is no such thing as a temporarily raise in boostlevel on a 3B like on the ABY. But i THOUGHT a mapped one can result in curve with a constant higher boost at some desired rpm? Like 0.95 bar at 4000rpm, 0.85 bar at 5000 rpm and 0.75 bar at 6000. I assume it all can be mapped to whatever the "customer" wants?

[audiman]

I assume it all can be mapped to whatever the "customer" wants?

As long as the turbo is capable of producing those levels of boost. If the turbo is too small then it will try and boost until it dies.

[1975DCS]

As long as the turbo is capable of producing those levels of boost. If the turbo is too small then it will try and boost until it dies.

Ofcourse! So no 3 bars of overboost then...