Achieving Maximum Boost?

[Smo]

My R is a 2.2 stroker mapped @ 1.7bar on a GT28RS turbo.

My question is this - why is it that my car rarely ever reaches 1.7bar boost? Most of the time I only manage 1.4/1.5bar on WOT all through the rev range. It's very frustrating as I'm not getting the potential from my car that I want. Sometimes it does reach 1.7bar but I want it to achieve this every time, not occassionally!

Cheers fellas.

 

[gtirjoey]

do you run a electronic boost controller? could be this playing up,
actuator spring possibly....
take it youve checked all your hose clamps are tight no vacuum leaks etc...

 

[Smo]

Yes mate, the car runs on an AVCR. Although now you mention it I have a funny feeling I noticed a jubilee the other day. I'll go over the whole lot and check.

 

[noriek2003]

what turbo ?

 

[Smo]

My R is a 2.2 stroker mapped @ 1.7bar on a GT28RS turbo.

My question is this - why is it that my car rarely ever reaches 1.7bar boost? Most of the time I only manage 1.4/1.5bar on WOT all through the rev range. It's very frustrating as I'm not getting the potential from my car that I want. Sometimes it does reach 1.7bar but I want it to achieve this every time, not occassionally!

Cheers fellas.

5 Characters.

 

[riske]

Hmmm. could be a number of things. could be boost controller, boost pipes, actuator spring. That 1.7 bar is quite high for that turbo but managable. i would check your boost guages first. quite hard too check the controller. What controller you have? its gain settings seem a bit off. to be loosing 0.2bar somewhere is quite a big thing. Explain in more detail and frequency of it hitting and missing. 1 out of 10 it hits or what?

 

[frp]

Are you sure the avc-r is set at 1.7bar or is it that its 1.5 and was peaking to 1.7 on the display? Might seem a silly question but some people dont know the difference (no offence to you). Im sure that turbo should hold 2-2.2bar at a push and i cant see 1.7bar been too much for it.
Could be actuator or the avc-r solenoid playing up?? has anything else been altered on the car recently?

steve

 

[campbellju]

Simple answer, if you want more hp, fit a bigger turbo. You can see at the top of the map the turbo doesn't really hold much above 1.5Bar (Minus 1.0Bar of the Y-Axis to get the turbo boost pressure). At a certain point in the rev range it might get to 1.7bar but will then get breathless. This is not how you use a compressor map properly but it gives a good guide.

Also, if you have a 2.2Bar stroker kit then it will generate higher hp at a lower boost pressure anyway.

On that turbo you will struggle to get past 360hp at whatever boost/cams you run. Again this isn't high you use a compressor map but look at the far right of the flow, multiple it by 10 and that gives a reasonable maximum for the achievable hp.

Garrett show all the maths on their website but it gets complicated quickly.

Quite a few people on here are downsizing their turbos to make their car more responsive on the street and track. Having a stroker with a small turbo will make the car very responsive which some will like but if you don't then fit a bigger turbo. Personally I wouldn't bother overboosting the turbo as it gives a spikey power delivery like a diesel where you get a big shove followed by a breathless feeling. So either turn your boost down, be happy with what you've got or fit a bigger turbo.

Jim

 

[Smo]

I figured the turbo might not be up to job! Luckily I've found a 3071r at a reasonable price so I think I know what to do

Thanks for the help guys!