Boost drop

[gtirx2]

Does anyone else get boost drop in the high revs on the standed turbo?I have put a forge aculator on it and it still drops in the high revs the boost holds almost a perfect bar untill you get to 5000+revs (with avc-r off)then drops to 0.7-0.8:?
Even with the avc-r i have to set the duty pretty high 75+% in the high revs to hold a solid bar.I was wondering if it was because i am running lean or rich in the high revs?
Also i have notest it holds slightly more boost if the car is fully loaded or working harder going up hill or something :? I thought it could be the gasket between the turbo and manifold but it seems fine as do all the gaskets
Anyway surely if the aculator is set to a bar it should hold a bar all the way to the redline?
I want to run even more boost but i need to sort this first as i am worried it could be running lean or to rich would this cause boost drop?
Thanks for any help :smokin:
ps.i may not be able to reply straight away not near pc to often.

 

[Studlife]

are you running a front mount or a top mount? the line from the plenum that sends air to the actuator is it the standard line (including hard line from topmount frame?) i had similar problem got it all sorted

 

[AJ4]

It never occured that your turbo / inlet system just can't hold 1 bar at that rpm ? turbos dont produce boost for ever, they have an efficiency range that you can safely run them over, which is affected by the efficiency of your whole inlet system ( air filter etc. ).

Sounds like your standard tubby is just running out of steam, could be worn if its still the original 15 year old one

 

[gtirx2]

Tanks

 

[gtirx2]

Thanks for the replys,no the intercooler is the d2 power kit i did wonder if it could be that but i am pretty sure it did it on the top mount aswell,as for the hose it has been changed for samco hose and the pipe run is a fare bit longer than standed but the apexi boost solinoid is still pretty close to the aculator?
AJ4 yes i did wonder if it could be the turbos efficiency but people on here say the standed turbo is good for 1.4bar?Like you said it could be the age of the turbo but it don't smoke and i have also checked around the wastegate houseing and that seems fine aswell no cracks.
Also i have recently rebuilt the engine with 87mm wiseco pistons and this should help the turbo push more boost as the ccs should now be 2046 shouldent it?
Sorry about last post finger sliped!

 

[AJ4]

lol, no worries. Just because it doesn't smoke doesn't necessarily mean its not worn. The compressor blades could be worn down, maybe the previous owners ran it with no air filter, you just dont know really. For example, if the edges of the blades were worn down enough then you'd be lucky to see any boost at all..

Standard tubbies can go up to 1.4, if they are in good condition, but even then they add so much heat to the inlet charge its probably not worth it. Admittedly, 1 bar does sound a bit low though...

 

[gtirx2]

You may have a point i'll have a look at the compresser soon and see what it looks like.anyway what sort of duty cycle do ather Rs run in the high revs for a bar?

 

[AJ4]

I've seen about 80% before at 1 bar, maxed out at 1.2 bar, but everyone has their own opinions on what power the standard injectors max out at. Once again its down to how good or bad the 15 year old injector is and what other mods you have.

As a ( very ) general rule of thumb, divide the injector size by 5 to find the maximum power for each cylinder. So standard = 440 / 5 = 88 bhp, multiplied by 4 cylinders = 88 * 4 = 352 bhp ( at 100% duty cycle ). If you figure in a max duty cycle of 85%, then the max bhp is roughly 352 * 0.85 = 299 bhp which is what you get at approx 1.2 Bar boost.

From experience of other owners, the figures seem to be about right. Some people can only run 1 bar max, others up to 1.4 bar max, but 1.2 seems to be the general limit.

 

[gtirx2]

Yer i see what you are saying i knew 1.2bar would proberly be the max for the injectors without running silly fuel pressure, i proberbly have not got a problem then its just went people say 1.4bar it made me think i could push that too but it seems it all down to other factors like turbo condtion engine spec etc.Anyway thanks for the info its made me feel better about my boost drop as it seems ather people have the same trouble as me and not everyone is pushing 1.4 on the standed turbo.